Datasheet TOP242R, TOP242GN Specification

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TOP242-249

TOPSwitch -GX

Extended Power, Design Flexible,

EcoSmart

Product Highlights

Lower System Cost, High Design Flexibility

• Extended power range to 250 W

• Features eliminate or reduce cost of external components

• Fully integrated soft-start for minimum stress/overshoot

• Externally programmable accurate current limit

• Wider duty cycle for more power, smaller input capacitor

• Separate line sense and current limit pins on Y/R packages

• Line under-voltage (UV) detection: no turn off glitches

• Line overvoltage (OV) shutdown extends line surge limit

• Line feed forward with maximum duty cycle (DC

reduction rejects line ripple and limits DC

• Frequency jittering reduces EMI and EMI filtering costs

• Regulates to zero load without dummy loading

• 132 kHz frequency reduces transformer/power supply size

• Half frequency option in Y/R packages for video applications

• Hysteretic thermal shutdown for automatic fault recovery

• Large thermal hysteresis prevents PC board overheating

EcoSmart

• Extremely low consumption in remote off mode (80 mW @ 110 VAC, 160 mW @ 230 VAC)

• Frequency lowered with load for high standby efficiency

• Allows shutdown/wake-up via LAN/input port

Description

TOPSwitch-GX uses the same proven topology as TOPSwitch, cost effectively integrating the high voltage power MOSFET, PWM control, fault protection and other control circuitry onto a single CMOS chip. Many new functions are integrated to reduce system cost and improve design flexibility, performance and energy efficiency.

Depending on package type, the TOPSwitch-GX family has either 1 or 3 additional pins over the standard DRAIN, SOURCE and CONTROL terminals. allowing the following functions: line sensing (OV/UV, line feedforward/DC max reduction), accurate externally set current limit, remote on/off, and synchronization to an external lower frequency and frequency selection (132 kHz/66 kHz).

- Energy Efficient

, Integrated Off-line Switcher

Family

at high line

MAX

)

Figure 1. Typical Flyback Application.

TOP242 P or G

TOP243 P or G

TOP244 P or G

TOPSwitch-GX

OUTPUT POWER TABLE

PRODUCT

TOP242 R TOP242 Y

TOP243 R TOP243 Y

TOP244 R TOP244 Y

TOP245 R TOP245 Y

TOP246 R TOP246 Y

TOP247 R TOP247 Y

TOP248 R TOP248 Y

TOP249 R TOP249 Y

230 VAC ±15%

Adapter

CONTROL

Open

Frame

85-265 VAC

Adapter

9 W 15 W 6.5 W 10 W 10 W 22 W 7 W 14 W 10 W 22 W 7 W 14 W

13 W 25 W 9 W 15 W 20 W 43 W 15 W 23 W 13 W 45 W 15 W 30 W

16 W 30 W 11 W 20 W 28 W 52 W 18 W 28 W 30 W 65 W 20 W 45 W

33 W 58 W 20 W 32 W 40 W 85 W 26 W 60 W

37 W 65 W 24 W 36 W 60 W 125 W 40 W 90 W

41 W 73 W 26 W 43 W 85 W 165 W 55 W 125 W

43 W 78 W 28 W 48 W

105 W 205 W 70 W 155 W

45 W 82 W 30 W 52 W

120 W 250 W 80 W 180 W

OUT

PI-2632-060200

Open

Frame

All package types provide the following transparent features: Soft-start, 132 kHz switching frequency (automatically reduced at light load), frequency jittering for lower EMI, wider DC

MAX

hysteretic thermal shutdown and larger creepage packages. In addition, all critical parameters (i.e. current limit, frequency, PWM gain) have tighter temperature and absolute tolerance, to simplify design and optimize system cost.

Table 1. Notes: 1. Typical continuous power in a non-ventilated enclosed adapter measured at 50 °C ambient. Assumes 1 sq. in. of 2 oz. copper heat sink area for R package. 2. Maximum practical

continuous power in an open frame design at 50 °C ambient. See Key Applications for detailed conditions. Assumes 3 sq. in. of 2 oz. copper heat sink area for R package. 3. See Part Ordering Information.

4. 230 VAC or 100/115 VAC with doubler.

July 2001

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TOP242-249

Section List

Functional Block Diagram......................................................................................................................................... 3

Pin Functional Description........................................................................................................................................ 4

TOPSwitch-GX Family Functional Description ........................................................................................................5

CONTROL (C) Pin Operation .................................................................................................................................6

Oscillator and Switching Frequency .......................................................................................................................6

Pulse Width Modulator and Maximum Duty Cycle ................................................................................................. 7

Light Load Frequency Reduction............................................................................................................................7

Error Amplifier......................................................................................................................................................... 7

On-chip Current Limit with External Programmability.............................................................................................7

Line Under-Voltage Detection (UV) ........................................................................................................................ 8

Line Overvoltage Shutdown (OV)...........................................................................................................................8

Line Feed Forward with DC

Remote ON/OFF and Synchronization................................................................................................................... 9

Soft-Start ................................................................................................................................................................9

Shutdown/Auto-Restart ..........................................................................................................................................9

Hysteretic Over-Temperature Protection ................................................................................................................9

Bandgap Reference................................................................................................................................................9

High-Voltage Bias Current Source........................................................................................................................10

Using Feature Pins.................................................................................................................................................... 11

FREQUENCY (F) Pin Operation........................................................................................................................... 11

LINE-SENSE (L) Pin Operation............................................................................................................................ 11

EXTERNAL CURRENT LIMIT (X) Pin Operation ................................................................................................. 11

MULTI-FUNCTION (M) Pin Operation .................................................................................................................. 12

Typical Uses of FREQUENCY (F) Pin ......................................................................................................................15

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins.......................................................16

Typical Uses of MULTI-FUNCTION (M) Pin ............................................................................................................. 19

Application Examples............................................................................................................................................... 21

A High Efficiency, 30 W, Universal Input Power Supply........................................................................................21

A High Efficiency, Enclosed, 70 W, Universal Adapter Supply..............................................................................22

A High Efficiency, 250 W, 250 - 380 VDC Input Power Supply.............................................................................23

Multiple Output, 60 W, 185 - 265 VAC Input Power Supply..................................................................................24

Processor Controlled Supply Turn On/Off ............................................................................................................25

Key Application Considerations ..............................................................................................................................27

TOPSwitch-II vs. TOPSwitch-GX..........................................................................................................................27

TOPSwitch-FX vs. TOPSwitch-GX.......................................................................................................................28

TOPSwitch-GX Design Considerations ................................................................................................................ 29

TOPSwitch-GX Layout Considerations.................................................................................................................31

Quick Design Checklist.........................................................................................................................................31

Design Tools ......................................................................................................................................................... 33

Reduction ..............................................................................................................8

MAX

Product Specifications and Test Conditions.......................................................................................................... 34

Typical Performance Characteristics ...................................................................................................................... 41

Part Ordering Information ........................................................................................................................................45

Package Outlines ......................................................................................................................................................45

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CONTROL (C)

EXTERNAL

CURRENT LIMIT (X)

LINE-SENSE (L)

FREQUENCY (F)

SHUNT REGULATOR/

ERROR AMPLIFIER

CURRENT

LIMIT

ADJUST

LINE

SENSE

+ V

1 V

5.8 V

I (LIMIT)

ON/OFF

OV/UV

START

5.8 V

4.8 V

SOFT

STOP LOGIC

MAX

OSCILLATOR WITH JITTER

INTERNAL UV

COMPARATOR

STOP

MAX

HALF FREQ.

SOFTSTART

CLOCK

MAX

SAW

LIGHT LOAD FREQUENCY REDUCTION

SOFT START

÷ 8

SHUTDOWN/

AUTO-RESTART

HYSTERETIC

THERMAL

SHUTDOWN

PWM

COMPARATOR

TOP242-249

INTERNAL SUPPLY

CURRENT LIMIT

COMPARATOR

CONTROLLED

TURN-ON

GATE DRIVER

SRQ

LEADING

EDGE

BLANKING

DRAIN (D)

Figure 2a. Functional Block Diagram (Y or R Package).

CONTROL (C)

MULTI-

FUNCTION (M)

SHUNT REGULATOR/

ERROR AMPLIFIER

CURRENT

LIMIT

ADJUST

LINE

SENSE

5.8 V

SOFT

MAX

4.8 V

STOP LOGIC

INTERNAL UV

COMPARATOR

5.8 V

I (LIMIT)

START

ON/OFF

+ V

OV/UV

OSCILLATOR WITH JITTER

STOP

MAX

SOURCE (S)

PI-2639-060600

INTERNAL SUPPLY

SOFT-

START

MAX

CLOCK

SAW

LIGHT LOAD FREQUENCY REDUCTION

SOFT START

÷ 8

SHUTDOWN/

AUTO-RESTART

HYSTERETIC

THERMAL

SHUTDOWN

PWM

COMPARATOR

SRQ

CURRENT LIMIT

COMPARATOR

CONTROLLED

TURN-ON

GATE DRIVER

LEADING

EDGE

BLANKING

DRAIN (D)

Figure 2b. Functional Block Diagram (P or G Package).

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PI-2631-061200

PI-2641-061200

SOURCE (S)

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TOP242-249

Pin Functional Description

DRAIN (D) Pin:

High voltage power MOSFET drain output. The internal startup bias current is drawn from this pin through a switched highvoltage current source. Internal current limit sense point for drain current.

CONTROL (C) Pin:

Error amplifier and feedback current input pin for duty cycle control. Internal shunt regulator connection to provide internal bias current during normal operation. It is also used as the connection point for the supply bypass and auto-restart/ compensation capacitor.

LINE-SENSE (L) Pin: (Y or R package only) Input pin for OV, UV, line feed forward with DC remote ON/OFF and synchronization. A connection to SOURCE pin disables all functions on this pin.

EXTERNAL CURRENT LIMIT (X) Pin: (Y or R package only) Input pin for external current limit adjustment, remote ON/OFF, and synchronization. A connection to SOURCE pin disables all functions on this pin.

reduction,

MAX

connected to SOURCE pin and 66 kHz if connected to CONTROL pin. The switching frequency is internally set for fixed 132 kHz operation in P and G packages.

SOURCE (S) Pin:

Output MOSFET source connection for high voltage power return. Primary side control circuit common and reference point.

2 MΩ

VUV = IUV x R V

OV = IOV x RLS

For RLS = 2 MΩ

= 100 VDC

= 450 VDC

@100 VDC = 78%

MAX

@375 VDC = 38%

MAX

For R I

= 69%

LIMIT

See fig. 55 for other resistor values (R to select different I values

Input

Voltage

CONTROL

12 kΩ

Figure 4. Y/R Package Line Sense and Externally Set Current

Limit.

= 12 kΩ

PI-2629-040501

)

LIMIT

MULTI-FUNCTION (M) Pin: (P or G package only) This pin combines the functions of the LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) pins of the Y package into one pin. Input pin for OV, UV, line feed forward with DC

MAX

reduction, external current limit adjustment, remote ON/OFF and synchronization. A connection to SOURCE pin disables all functions on this pin and makes TOPSwitch-GX operate in simple three terminal mode (like TOPSwitch-II).

FREQUENCY (F) Pin: (Y or R package only) Input pin for selecting switching frequency: 132 kHz if

Y Package (TO-220-7C)

Tab Internally Connected to

SOURCE Pin

7 D 5 F

4 S 3 X 2 L 1 C

R Package

(TO-263-7C)

P Package (DIP-8B)

G Package (SMD-8B)

Figure 3. Pin Configuration (top view).

8 7

12345 7

CLX SF D

PI-2724-033001

VUV = IUV x R V

OV = IOV x RLS

2 MΩ

For RLS = 2 MΩ V

= 100 VDC

OV =

@100 VDC = 78%

MAX

@375 VDC = 38%

MAX

For R

LIMIT

For R

LIMIT

See fig. 55 for other resistor values (R to select different I

values

LIMIT

Input

Voltage

CONTROL

Figure 5. P/G Package Line Sense.

Input

Voltage

Figure 6. P/G Package Externally Set Current Limit.

CONTROL

450 VDC

PI-2509-040501

= 12 kΩ

= 69%

= 25 kΩ

= 43%

PI-2517-040501

)

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TOP242-249

TOPSwitch-GX

Family Functional Description

Like TOPSwitch, TOPSwitch-GX is an integrated switched mode power supply chip that converts a current at the control input to a duty cycle at the open drain output of a high voltage power MOSFET. During normal operation the duty cycle of the power MOSFET decreases linearly with increasing CONTROL pin current as shown in Figure 7.

In addition to the three terminal TOPSwitch features, such as the high voltage start-up, the cycle-by-cycle current limiting, loop compensation circuitry, auto-restart, thermal shutdown, the TOPSwitch-GX incorporates many additional functions that reduce system cost, increase power supply performance and design flexibility. A patented high voltage CMOS technology allows both the high voltage power MOSFET and all the low voltage control circuitry to be cost effectively integrated onto a single monolithic chip.

Three terminals, FREQUENCY, LINE-SENSE, and EXTERNAL CURRENT LIMIT (available in Y or R package) or one terminal MULTI-FUNCTION (available in P or G Package) have been added to implement some of the new functions. These terminals can be connected to the SOURCE pin to operate the TOPSwitch-GX in a TOPSwitch-like three terminal mode. However, even in this three terminal mode, the TOPSwitch-GX offers many new transparent features that do not require any external components:

Auto-restart

132

Frequency (kHz)

Auto-restart

Duty Cycle (%)

CD1

IL = 190 µA

IC (mA)

IL = 125 µA

Slope = PWM Gain

= 125 µA

IL < I

L(DC)

1. A fully integrated 10 ms soft-start limits peak currents and voltages during start-up and dramatically reduces or eliminates output overshoot in most applications.

2. DC

of 78% allows smaller input storage capacitor, lower

MAX

input voltage requirement and/or higher power capability.

3. Frequency reduction at light loads lowers the switching losses and maintains good cross regulation in multiple output supplies.

4. Higher switching frequency of 132 kHz reduces the transformer size with no noticeable impact on EMI.

5. Frequency jittering reduces EMI.

6. Hysteretic over-temperature shutdown ensures automatic recovery from thermal fault. Large hysteresis prevents circuit board overheating.

7. Packages with omitted pins and lead forming provide large drain creepage distance.

8. Tighter absolute tolerances and smaller temperature variations on switching frequency, current limit and PWM gain.

The LINE-SENSE (L) pin is usually used for line sensing by connecting a resistor from this pin to the rectified DC high voltage bus to implement line overvoltage (OV), under-voltage (UV) and line feed forward with DC

reduction. In this

MAX

mode, the value of the resistor determines the OV/UV thresholds and the DC

is reduced linearly starting from a line voltage

MAX

above the under-voltage threshold. See Table 2 and Figure 11.

TOP242/5 1.6 2.0 TOP246/9 2.2 2.6

IC (mA)

Note: For P and G packages IL is replaced with IM.

Figure 7. Relationship of Duty Cycle and Frequency to CONTROL

Pin Current.

5.2 6.0

5.8 6.6

PI-2633-060500

The pin can also be used as a remote ON/OFF and a synchronization input.

The EXTERNAL CURRENT LIMIT (X) pin is usually used to reduce the current limit externally to a value close to the operating peak current, by connecting the pin to SOURCE through a resistor. This pin can also be used as a remote ON/OFF and a synchronization input in both modes. See Table 2 and Figure 11.

For the P or G packages the LINE-SENSE and EXTERNAL CURRENT LIMIT pin functions are combined on one MULTIFUNCTION (M) pin. However, some of the functions become mutually exclusive as shown in Table 3.

The FREQUENCY (F) pin in the Y or R package sets the switching frequency to the default value of 132 kHz when connected to SOURCE pin. A half frequency option of 66 kHz can be chosen by connecting this pin to CONTROL pin instead. Leaving this pin open is not recommended.

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TOP242-249

CONTROL (C) Pin Operation

The CONTROL pin is a low impedance node that is capable of receiving a combined supply and feedback current. During normal operation, a shunt regulator is used to separate the feedback signal from the supply current. CONTROL pin voltage VC is the supply voltage for the control circuitry including the MOSFET gate driver. An external bypass capacitor closely connected between the CONTROL and SOURCE pins is required to supply the instantaneous gate drive current. The total amount of capacitance connected to this pin also sets the auto-restart timing as well as control loop compensation.

When rectified DC high voltage is applied to the DRAIN pin during start-up, the MOSFET is initially off, and the CONTROL pin capacitor is charged through a switched high voltage current source connected internally between the DRAIN and CONTROL pins. When the CONTROL pin voltage VC reaches approximately 5.8 V, the control circuitry is activated and the soft-start begins. The soft-start circuit gradually increases the duty cycle of the MOSFET from zero to the maximum value over approximately 10 ms. If no external feedback/supply current is fed into the CONTROL pin by the end of the soft-start, the high voltage current source is turned off and the CONTROL pin will start discharging in response to the supply current drawn by the control circuitry. If the power supply is designed properly, and no fault condition such as open loop or shorted output exists, the feedback loop will close, providing external CONTROL pin current, before the CONTROL pin voltage has had a chance to discharge to the lower threshold voltage of approximately 4.8 V (internal supply under-voltage lockout threshold). When the externally fed current charges the CONTROL pin to the shunt regulator voltage of 5.8 V, current

in excess of the consumption of the chip is shunted to SOURCE through resistor RE as shown in Figure 2. This current flowing through RE controls the duty cycle of the power MOSFET to provide closed loop regulation. The shunt regulator has a finite low output impedance ZC that sets the gain of the error amplifier when used in a primary feedback configuration. The dynamic impedance ZC of the CONTROL pin together with the external CONTROL pin capacitance sets the dominant pole for the control loop.

When a fault condition such as an open loop or shorted output prevents the flow of an external current into the CONTROL pin, the capacitor on the CONTROL pin discharges towards 4.8 V. At 4.8 V, auto-restart is activated which turns the output MOSFET off and puts the control circuitry in a low current standby mode. The high-voltage current source turns on and charges the external capacitance again. A hysteretic internal supply under-voltage comparator keeps VC within a window of typically 4.8 to 5.8 V by turning the high-voltage current source on and off as shown in Figure 8. The auto-restart circuit has a divide-by-8 counter which prevents the output MOSFET from turning on again until eight discharge/charge cycles have elapsed. This is accomplished by enabling the output MOSFET only when the divide-by-8 counter reaches full count (S7). The counter effectively limits TOPSwitch-GX power dissipation by reducing the auto-restart duty cycle to typically 4%. Autorestart mode continues until output voltage regulation is again achieved through closure of the feedback loop.

Oscillator and Switching Frequency

The internal oscillator linearly charges and discharges an internal capacitance between two voltage levels to create a sawtooth

LINE

0 V

DRAIN

0 V

OUT

0 V

Note: S0 through S7 are the output states of the auto-restart counter

Figure 8. Typical Waveforms for (1) Power Up (2) Normal Operation (3) Auto-restart (4) Power Down.

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S1 S2 S6 S7 S1 S2 S6 S7S0

S1 S7

S6 S7

5.8 V

4.8 V

PI-2545-082299

Page 7

waveform for the pulse width modulator. This oscillator sets the pulse width modulator/current limit latch at the beginning of each cycle.

The nominal switching frequency of 132 kHz was chosen to minimize transformer size while keeping the fundamental EMI frequency below 150 kHz. The FREQUENCY pin (available only in Y or R package), when shorted to the CONTROL pin, lowers the switching frequency to 66 kHz (half frequency) which may be preferable in some cases such as noise sensitive video applications or a high efficiency standby mode. Otherwise, the FREQUENCY pin should be connected to the SOURCE pin for the default 132 kHz.

TOP242-249

Switching

Frequency

DRAIN

Figure 9. Switching Frequency Jitter. (Idealized V

136 kHz

128 kHz

4 ms

waveform)

DRAIN

PI-2550-092499

Time

To further reduce the EMI level, the switching frequency is jittered (frequency modulated) by approximately ±4 kHz at 250 Hz (typical) rate as shown in Figure 9. Figure 46 shows the typical improvement of EMI measurements with frequency jitter.

Pulse Width Modulator and Maximum Duty Cycle

The pulse width modulator implements voltage mode control by driving the output MOSFET with a duty cycle inversely proportional to the current into the CONTROL pin that is in excess of the internal supply current of the chip (see Figure 7). The excess current is the feedback error signal that appears across RE (see Figure 2). This signal is filtered by an RC network with a typical corner frequency of 7 kHz to reduce the effect of switching noise in the chip supply current generated by the MOSFET gate driver. The filtered error signal is compared with the internal oscillator sawtooth waveform to generate the duty cycle waveform. As the control current increases, the duty cycle decreases. A clock signal from the oscillator sets a latch which turns on the output MOSFET. The pulse width modulator resets the latch, turning off the output MOSFET. Note that a minimum current must be driven into the CONTROL pin before the duty cycle begins to change.

The maximum duty cycle, DC

is set at a default maximum

MAX,

value of 78% (typical). However, by connecting the LINESENSE or MULTI-FUNCTION pin (depending on the package) to the rectified DC high voltage bus through a resistor with appropriate value, the maximum duty cycle can be made to decrease from 78% to 38% (typical) as shown in Figure 11 when input line voltage increases (see line feed forward with DC

MAX

reduction).

Light Load Frequency Reduction

The pulse width modulator duty cycle reduces as the load at the power supply output decreases. This reduction in duty cycle is proportional to the current flowing into the CONTROL pin. As the CONTROL pin current increases, the duty cycle decreases linearly towards a duty cycle of 10%. Below 10% duty cycle, to maintain high efficiency at light loads, the frequency is also reduced linearly until a minimum frequency is reached at a duty

cycle of 0% (refer to Figure 7). The minimum frequency is typically 30 kHz and 15 kHz for 132 kHz and 66 kHz operation, respectively.

This feature allows a power supply to operate at lower frequency at light loads thus lowering the switching losses while maintaining good cross regulation performance and low output ripple.

Error Amplifier

The shunt regulator can also perform the function of an error amplifier in primary side feedback applications. The shunt regulator voltage is accurately derived from a temperaturecompensated bandgap reference. The gain of the error amplifier is set by the CONTROL pin dynamic impedance. The CONTROL pin clamps external circuit signals to the V voltage level. The CONTROL pin current in excess of the supply current is separated by the shunt regulator and flows through RE as a voltage error signal.

On-chip Current Limit with External Programmability

The cycle-by-cycle peak drain current limit circuit uses the output MOSFET ON-resistance as a sense resistor. A current limit comparator compares the output MOSFET on-state drain to source voltage, V current causes V

DS(ON)

with a threshold voltage. High drain

DS(ON)

to exceed the threshold voltage and turns the output MOSFET off until the start of the next clock cycle. The current limit comparator threshold voltage is temperature compensated to minimize the variation of the current limit due to temperature related changes in R

of the output MOSFET.

DS(ON)

The default current limit of TOPSwitch-GX is preset internally. However, with a resistor connected between EXTERNAL CURRENT LIMIT (X) pin (Y or R package) or MULTIFUNCTION (M) pin (P or G package) and SOURCE pin, current limit can be programmed externally to a lower level between 30% and 100% of the default current limit. Please refer to the graphs in the typical performance characteristics section for the selection of the resistor value. By setting current limit low, a larger TOPSwitch-GX than necessary for the power required can be used to take advantage of the lower R

DS(ON)

for

higher efficiency/smaller heat sinking requirements. With a

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TOP242-249

second resistor connected between the EXTERNAL CURRENT LIMIT (X) pin (Y or R package) or MULTI-FUNCTION (M) pin (P or G package) and the rectified DC high voltage bus, the current limit is reduced with increasing line voltage, allowing a true power limiting operation against line variation to be implemented. When using an RCD clamp, this power limiting technique reduces maximum clamp voltage at high line. This allows for higher reflected voltage designs as well as reducing clamp dissipation.

The leading edge blanking circuit inhibits the current limit comparator for a short time after the output MOSFET is turned on. The leading edge blanking time has been set so that, if a power supply is designed properly, current spikes caused by primary-side capacitances and secondary-side rectifier reverse recovery time should not cause premature termination of the switching pulse.

The current limit is lower for a short period after the leading edge blanking time as shown in Figure 52. This is due to dynamic characteristics of the MOSFET. To avoid triggering the current limit in normal operation, the drain current waveform should stay within the envelope shown.

Line Under-Voltage Detection (UV)

At power up, UV keeps TOPSwitch-GX off until the input line voltage reaches the under voltage threshold. At power down, UV prevents auto-restart attempts after the output goes out of regulation. This eliminates power down glitches caused by the slow discharge of large input storage capacitor present in applications such as standby supplies. A single resistor connected from the LINE-SENSE pin (Y or R package) or MULTIFUNCTION pin (P or G package) to the rectified DC high voltage bus sets UV threshold during power up. Once the power supply is successfully turned on, the UV threshold is lowered to

40% of the initial UV threshold to allow extended input voltage operating range (UV low threshold). If the UV low threshold is reached during operation without the power supply losing regulation the device will turn off and stay off until UV (high threshold) has been reached again. If the power supply loses regulation before reaching the UV low threshold, the device will enter auto-restart. At the end of each auto-restart cycle (S7), the UV comparator is enabled. If the UV high threshold is not exceeded the MOSFET will be disabled during the next cycle (see figure 8). The UV feature can be disabled independent of OV feature as shown in Figure 19 and 23.

Line Overvoltage Shutdown (OV)

The same resistor used for UV also sets an overvoltage threshold which, once exceeded, will force TOPSwitch-GX output into off-state. The ratio of OV and UV thresholds is preset at 4.5 as can be seen in Figure 11. When the MOSFET is off, the rectified DC high voltage surge capability is increased to the voltage rating of the MOSFET (700 V), due to the absence of the reflected voltage and leakage spikes on the drain. A small amount of hysteresis is provided on the OV threshold to prevent noise triggering. The OV feature can be disabled independent of the UV feature as shown in Figure 18 and 32.

Line Feed Forward with DC

Reduction

MAX

The same resistor used for UV and OV also implements line voltage feed forward which minimizes output line ripple and reduces power supply output sensitivity to line transients. This feed forward operation is illustrated in Figure 7 by the different values of IL (Y or R package) or IM (P or G Package). Note that for the same CONTROL pin current, higher line voltage results in smaller operating duty cycle. As an added feature, the maximum duty cycle DC

is also reduced from 78% (typical)

MAX

at a voltage slightly higher than the UV threshold to 38% (typical) at the OV threshold (see Figures 7, 11). Limiting

Oscillator

(SAW)

MAX

X, L or M Pin (STOP)

Figure 10. Synchronization Timing Diagram.

Enable from

E 7/01

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Time

PI-2637-060600

Page 9

at higher line voltages helps prevent transformer

MAX

saturation due to large load transients in forward converter applications. DC

of 38% at the OV threshold was chosen to

MAX

ensure that the power capability of the TOPSwitch-GX is not restricted by this feature under normal operation.

Remote ON/OFF and Synchronization

TOPSwitch-GX can be turned on or off by controlling the current into the LINE-SENSE pin or out from the EXTERNAL CURRENT LIMIT pin (Y or R package) and into or out from the MULTI-FUNCTION pin (P or G package) (see Figure 11). In addition, the LINE-SENSE pin has a 1 V threshold comparator connected at its input. This voltage threshold can also be used to perform remote ON/OFF control. This allows easy implementation of remote ON/OFF control of TOPSwitch-GX in several different ways. A transistor or an optocoupler output connected between the EXTERNAL CURRENT LIMIT or LINE-SENSE pins (Y or R package) or the MULTI-FUNCTION pin (P or G package) and the SOURCE pin implements this function with “active-on” (Figure 22, 29 and 36) while a transistor or an optocoupler output connected between the LINE-SENSE pin (Y or R package) or the MULTI-FUNCTION (P or G package) pin and the CONTROL pin implements the function with “active-off” (Figure 23 and 37).

When a signal is received at the LINE-SENSE pin or the EXTERNAL CURRENT LIMIT pin (Y or R package) or the MULTI-FUNCTION pin (P or G package) to disable the output through any of the pin functions such as OV, UV and remote ON/OFF, TOPSwitch-GX always completes its current switching cycle, as illustrated in Figure 10, before the output is forced off. The internal oscillator is stopped slightly before the end of the current cycle and stays there as long as the disable signal exists. When the signal at the above pins changes state from disable to enable, the internal oscillator starts the next switching cycle. This approach allows the use of this pin to synchronize TOPSwitch-GX to any external signal with a frequency lower than its internal switching frequency.

TOP242-249

open). When the TOPSwitch-GX is remotely turned on after entering this mode, it will initiate a normal start-up sequence with soft-start the next time the CONTROL pin reaches 5.8 V. In the worst case, the delay from remote on to start-up can be equal to the full discharge/charge cycle time of the CONTROL pin, which is approximately 125 ms for a 47 µF CONTROL pin capacitor. This reduced consumption remote off mode can eliminate expensive and unreliable in-line mechanical switches. It also allows for microprocessor controlled turn-on and turnoff sequences that may be required in certain applications such as inkjet and laser printers.

Soft-Start

Two on-chip soft-start functions are activated at start-up with a duration of 10 ms (typical). Maximum duty cycle starts from 0% and linearly increases to the default maximum of 78% at the end of the 10 ms duration and the current limit starts from about 85% and linearly increases to 100% at the end of the 10ms duration. In addition to start-up, soft-start is also activated at each restart attempt during auto-restart and when restarting after being in hysteretic regulation of CONTROL pin voltage (V

), due to remote off or thermal shutdown conditions. This

effectively minimizes current and voltage stresses on the output MOSFET, the clamp circuit and the output rectifier during startup. This feature also helps minimize output overshoot and prevents saturation of the transformer during start-up.

Shutdown/Auto-Restart

To minimize TOPSwitch-GX power dissipation under fault conditions, the shutdown/auto-restart circuit turns the power supply on and off at an auto-restart duty cycle of typically 4% if an out of regulation condition persists. Loss of regulation interrupts the external current into the CONTROL pin. V regulation changes from shunt mode to the hysteretic autorestart mode as described in CONTROL pin operation section. When the fault condition is removed, the power supply output becomes regulated, VC regulation returns to shunt mode, and normal operation of the power supply resumes.

As seen above, the remote ON/OFF feature allows the TOPSwitch-GX to be turned on and off instantly, on a cycle-bycycle basis, with very little delay. However, remote ON/OFF can also be used as a standby or power switch to turn off the TOPSwitch-GX and keep it in a very low power consumption state for indefinitely long periods. If the TOPSwitch-GX is held in remote off state for long enough time to allow the CONTROL pin to dishcharge to the internal supply under-voltage threshold of 4.8 V (approximately 32 ms for a 47 µF CONTROL pin capacitance), the CONTROL pin goes into the hysteretic mode of regulation. In this mode, the CONTROL pin goes through alternate charge and discharge cycles between 4.8 V and 5.8 V (see CONTROL pin operation section above) and runs entirely off the high voltage DC input, but with very low power consumption (160 mW typical at 230 VAC with M or X pins

Hysteretic Over-Temperature Protection

Temperature protection is provided by a precision analog circuit that turns the output MOSFET off when the junction temperature exceeds the thermal shutdown temperature (140 °C typical). When the junction temperature cools to below the hysteretic temperature, normal operation resumes providing automatic recovery. A large hysteresis of 70 °C (typical) is provided to prevent overheating of the PC board due to a continuous fault condition. VC is regulated in hysteretic mode and a 4.8 V to 5.8 V (typical) sawtooth waveform is present on the CONTROL pin while in thermal shutdown.

Bandgap Reference

All critical TOPSwitch-GX internal voltages are derived from a temperature-compensated bandgap reference. This reference is

August 8, 2000

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Page 10

TOP242-249

also used to generate a temperature-compensated current reference which is trimmed to accurately set the switching frequency, MOSFET gate drive current, current limit, and the line OV/UV thresholds. TOPSwitch-GX has improved circuitry to maintain all of the above critical parameters within very tight absolute and temperature tolerances.

High-Voltage Bias Current Source

This current source biases TOPSwitch-GX from the DRAIN pin and charges the CONTROL pin external capacitance during start-up or hysteretic operation. Hysteretic operation occurs during auto-restart, remote off and over-temperature shutdown. In this mode of operation, the current source is switched on and off with an effective duty cycle of approximately 35%. This duty cycle is determined by the ratio of CONTROL pin charge (I

) and discharge currents (I

is turned off during normal operation when the output MOSFET is switching. The effect of the current source switching will be seen on the DRAIN voltage waveform as small disturbances and is normal.

CD1

and I

). This current source

CD2

E 7/01

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Page 11

Using Feature Pins

TOP242-249

FREQUENCY (F) Pin Operation

The FREQUENCY pin is a digital input pin available in the Y or R package only. Shorting the FREQUENCY pin to SOURCE pin selects the nominal switching frequency of 132 kHz (Figure 13) which is suited for most applications. For other cases that may benefit from lower switching frequency such as noise sensitive video applications, a 66 kHz switching frequency (half frequency) can be selected by shorting the FREQUENCY pin to the CONTROL pin (Figure 14). In addition, an example circuit shown in Figure 15 may be used to lower the switching frequency from 132 kHz in normal operation to 66 kHz in standby mode for very low standby power consumption.

LINE-SENSE (L) Pin Operation (Y and R Packages)

When current is fed into the LINE-SENSE pin, it works as a voltage source of approximately 2.6 V up to a maximum current of +400 µA (typical). At +400 µA, this pin turns into a constant current sink. Refer to Figure 12a. In addition, a comparator with a threshold of 1 V is connected at the pin and is used to detect when the pin is shorted to the SOURCE pin.

There are a total of four functions available through the use of the LINE-SENSE pin: OV, UV, line feed forward with DC

MAX

reduction, and remote ON/OFF. Connecting the LINE-SENSE pin to the SOURCE pin disables all four functions. The LINESENSE pin is typically used for line sensing by connecting a resistor from this pin to the rectified DC high voltage bus to implement OV, UV and DC

reduction with line voltage. In

MAX

this mode, the value of the resistor determines the line OV/UV thresholds, and the DC

is reduced linearly with rectified DC

MAX

high voltage starting from just above the UV threshold. The pin can also be used as a remote on/off and a synchronization input.

Refer to Table 2 for possible combinations of the functions with example circuits shown in Figure 16 through Figure 40. A description of specific functions in terms of the LINE-SENSE pin I/V characteristic is shown in Figure 11 (right hand side). The horizontal axis represents LINE-SENSE pin current with positive polarity indicating currents flowing into the pin. The meaning of the vertical axes varies with functions. For those that control the on/off states of the output such as UV, OV and remote ON/OFF, the vertical axis represents the enable/disable states of the output. UV triggers at IUV (+50 µA typical with 30 µA hysteresis) and OV triggers at IOV (+225 µA typical with 8 µA hysteresis). Between the UV and OV thresholds, the output is enabled. For line feed forward with DC the vertical axis represents the magnitude of the DC feed forward with DC from 78% at I

L(DC)

reduction lowers maximum duty cycle

MAX

(+60 µA typical) to 38% at IOV (+225 µA).

reduction,

MAX

. Line

EXTERNAL CURRENT LIMIT (X) Pin Operation (Y and R Packages)

When current is drawn out of the EXTERNAL CURRENT LIMIT pin, it works as a voltage source of approximately 1.3 V up to a maximum current of –240 µA (typical). At –240 µA, it turns into a constant current source (refer to Figure 12a).

There are two functions available through the use of the EXTERNAL CURRENT LIMIT pin: external current limit and remote ON/OFF. Connecting the EXTERNAL CURRENT LIMIT pin and SOURCE pin disables the two functions. In high efficiency applications this pin can be used to reduce the current limit externally to a value close to the operating peak current, by connecting the pin to the SOURCE pin through a resistor. The pin can also be used as a remote on/off. Table 2 shows several possible combinations using this pin. See Figure

LINE-SENSE AND EXTERNAL CURRENT LIMIT PIN TABLE*

Figure Number Three Terminal Operation

Under-Voltage Overvoltage Line Feed Forward (DC Overload Power Limiting External Current Limit Remote ON/OFF

*This table is only a partial list of many LINE-SENSE and EXTERNAL CURRENT LIMIT pin configurations that are possible.

Table 2. Typical LINE-SENSE and EXTERNAL CURRENT LIMIT Pin Configurations.

▲

MAX

16 17 18 19 20 21 22 23 24 25 26 27 28 29

✔

✔✔ ✔ ✔ ✔

✔✔ ✔✔✔

)

✔✔✔✔

✔

✔✔ ✔✔ ✔✔

✔✔✔✔✔✔ ✔

August 8, 2000

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TOP242-249

Figure Number

MULTI-FUNCTION PIN TABLE*

▲

30 31 32 33 34 35 36 37 38 39 40

Three Terminal Operation Under-Voltage Overvoltage Line Feed Forward (DC

MAX

)

✔

✔✔ ✔

✔✔

Overload Power Limiting External Current Limit

✔✔ ✔✔

Remote ON/OFF

*This table is only a partial list of many MULTI-FUNCTION pin configurations that are possible.

Table 3. Typical MULTI-FUNCTION Pin Configurations.

11 for a description of the functions where the horizontal axis (left hand side) represents the EXTERNAL CURRENT LIMIT pin current. The meaning of the vertical axes varies with function. For those that control the on/off states of the output such as remote ON/OFF, the vertical axis represents the enable/ disable states of the output. For external current limit, the vertical axis represents the magnitude of the I

. Please see

LIMIT

graphs in the typical performance characteristics section for the current limit programming range and the selection of appropriate resistor value.

TOPSwitch-GX to operate in a simple three terminal mode like TOPSwitch-II. The MULTI-FUNCTION pin is typically used

for line sensing by connecting a resistor from this pin to the rectified DC high voltage bus to implement OV, UV and DC reduction with line voltage. In this mode, the value of the resistor determines the line OV/UV thresholds, and the DC is reduced linearly with rectified DC high voltage starting from just above the UV threshold. In high efficiency applications this pin can be used in the external current limit mode instead, to reduce the current limit externally to a value close to the operating peak current, by connecting the pin to the SOURCE

MULTI-FUNCTION (M) Pin Operation (P and G Packages)

The LINE-SENSE and EXTERNAL CURRENT LIMIT pin functions are combined to a single MULTI-FUNCTION pin for P and G packages. The comparator with a 1 V threshold at the LINE-SENSE pin is removed in this case as shown in Figure 2b. All of the other functions are kept intact. However, since some of the functions require opposite polarity of input current (MULTI-FUNCTION pin), they are mutually exclusive. For example, line sensing features cannot be used simultaneously with external current limit setting. When current is fed into the MULTI-FUNCTION pin, it works as a voltage source of approximately 2.6 V up to a maximum current of +400 µA (typical). At +400 µA, this pin turns into a constant current sink. When current is drawn out of the MULTI-FUNCTION pin, it works as a voltage source of approximately 1.3 V up to a maximum current of –240 µA (typical). At –240 µA, it turns into a constant current source. Refer to Figure 12b.

pin through a resistor. The same pin can also be used as a remote on/off and a synchronization input in both modes. Please refer to Table 3 for possible combinations of the functions with example circuits shown in Figure 30 through Figure 40. A description of specific functions in terms of the MULTIFUNCTION pin I/V characteristic is shown in Figure 11. The horizontal axis represents MULTI-FUNCTION pin current with positive polarity indicating currents flowing into the pin. The meaning of the vertical axes varies with functions. For those that control the on/off states of the output such as UV, OV and remote ON/OFF, the vertical axis represents the enable/ disable states of the output. UV triggers at IUV (+50 µA typical) and OV triggers at IOV (+225 µA typical with 30 µA hysteresis). Between the UV and OV thresholds, the output is enabled. For external current limit and line feed forward with DC reduction, the vertical axis represents the magnitude of the I and DC

. Line feed forward with DC

MAX

maximum duty cycle from 78% at I

There are a total of five functions available through the use of the MULTI-FUNCTION pin: OV, UV, line feed forward with DC

reduction, external current limit and remote ON/OFF. A

MAX

short circuit between the MULTI-FUNCTION pin and SOURCE pin disables all five functions and forces

at IOV (+225 µA). External current limit is available only with negative MULTI-FUNCTION pin current. Please see graphs in the typical performance characteristics section for the current limit programming range and the selection of appropriate resistor value.

✔

✔✔✔✔✔

MAX

reduction lowers

MAX

(+60 µA typical) to 38%

M(DC)

LIMIT

E 7/01

August 8, 2000

Page 13

M Pin

TOP242-249

L PinX Pin

Output MOSFET Switching

Current

Limit

Maximum

Duty Cycle

(Enabled)

(Disabled)

(Default)

LIMIT

(78.5%)

MAX

-22 µA

-27 µA

REM(N)

Disabled when supply output goes out of regulation

+ V

Pin Voltage

-250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400

X and L Pins (Y or R Package) and M Pin (P or G Package) Current (µA)

Note: This figure provides idealized functional characteristics with typical performance values. Please refer to the parametric table and typical performance characteristics sections of the data sheet for measured data.

PI-2636-040501

Figure 11. MULTI-FUNCTION (P or G package), LINE-SENSE, and EXTERNAL CURRENT LIMIT (Y or R package) Pin Characteristics.

August 8, 2000

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Page 14

TOP242-249

CONTROL Pin

EXTERNAL CURRENT LIMIT (X)

LINE-SENSE (L)

240 µA

VBG + V

TOPSwitch-GX

(Negative Current Sense - ON/OFF,

Current Limit Adjustment)

(Voltage Sense)

1 V

(Positive Current Sense - Under-Voltage,

Overvoltage, ON/OFF Maximum Duty

400 µA

Cycle Reduction)

Figure 12a. LINE-SENSE (L), and EXTERNAL CURRENT LIMIT (X) Pin Input Simplified Schematic.

P and G Package

Y and R Package

CONTROL Pin

240 µA

TOPSwitch-GX

PI-2634-033001

(Negative Current Sense - ON/OFF,

VBG + V

MULTI-FUNCTION (M)

400 µA

Figure 12b. MULTI-FUNCTION (M) Pin Input Simplified Schematic.

Current Limit Adjustment)

(Positive Current Sense - Under-Voltage,

Overvoltage, Maximum Duty

Cycle Reduction)

PI-2548-092399

E 7/01

August 8, 2000

Page 15

Typical Uses of FREQUENCY (F) Pin

TOP242-249

Input

Voltage

CONTROL

PI-2654-071700

Input

Voltage

CONTROL

Figure 13. Full Frequency Operation (132 kHz). Figure 14. Half Frequency Operation (66 kHz).

Input

Voltage

QS can be an optocoupler output.

CONTROL

PI-2655-071700

20 kΩ

1 nF

47 kΩ

STANDBY

PI-2656-040501

Figure 15. Half Frequency Standby Mode (For High Standby

Efficiency).

August 8, 2000

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Page 16

TOP242-249

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins

CLXS F D

Input

Voltage

CONTROL

CS D

PI-2617-050100

Figure 16. Three Terminal Operation (LINE-SENSE and

EXTERNAL CURRENT LIMIT Features Disabled. FREQUENCY Pin can be tied to SOURCE or CONTROL Pin).

2 MΩ

Input

22 kΩ

Voltage

6.2 V

CONTROL

Figure 18. Line-Sensing for Under-Voltage Only (Overvoltage

Disabled).

VUV = RLS x I For Value Shown

= 100 VDC

PI-2510-040501

VUV = IUV x R V

OV = IOV x RLS

For RLS = 2 MΩ

2MΩR

= 100 VDC

OV =

@100 VDC = 78%

MAX

@375 VDC = 38%

MAX

450 VDC

PI-2618-040501

Input

Voltage

CONTROL

Figure 17. Line-Sensing for Under-Voltage, Overvoltage and

Line Feed Forward.

2 MΩ

= I

OV x RLS

For Values Shown

= 450 VDC

Input

Voltage

30 kΩ

CONTROL

1N4148

PI-2620-040501

Figure 19. Line-Sensing for Overvoltage Only (Under-Voltage

Disabled). Maximum Duty Cycle will be reduced at Low Line.

Input

Voltage

CONTROL

Figure 20. Externally Set Current Limit.

E 7/01

August 8, 2000

For R

= 12 kΩ

I For R

LIMIT

= 25 kΩ

LIMIT

= 69%

= 43%

See fig. 55 for other resistor values (R

PI-2623-040501

2.5 MΩR

)

Input

Voltage

CONTROL

R 6 kΩ

100% @ 100 VDC

LIMIT

63% @ 300 VDC

LIMIT

PI-2624-040501

Figure 21. Current Limit Reduction with Line Voltage.

Page 17

TOP242-249

T ypical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)

QR can be an optocoupler output or can be replaced by a manual switch.

Input

Voltage

CONTROL

47 kΩ

ON/OFF

Figure 22. Active-on (Fail Safe) Remote ON/OFF.

Input

Voltage

CONTROL

can be an optocoupler

output or can be replaced by a manual switch.

For R I

PI-2625-040501

12 kΩ

= 69 %

LIMIT

25 kΩ

= 43 %

LIMIT

QR can be an optocoupler output or can be replaced by a manual switch.

Input

ON/OFF

47 kΩ

45 kΩ

Voltage

CONTROL

PI-2621-040501

Figure 23. Active-off Remote ON/OFF. Maximum Duty Cycle will

be reduced.

Input

Voltage

ON/OFF

47 kΩ

CONTROL

45 kΩ

QR can be an optocoupler output or can be replaced by a manual switch.

47 kΩ

ON/OFF

PI-2626-040501

Figure 24. Active-on Remote ON/OFF with Externally Set Current

Limit.

Input

Voltage

ON/OFF

47 kΩ

CONTROL

2 MΩ

can be an optocoupler

output or can be replaced by a manual switch.

For RLS = 2 MΩ

= 100 VDC

= 450 VDC

PI-2622-040501

Figure 26. Active-off Remote ON/OFF with LINE-SENSE.

PI-2627-040501

Figure 25. Active-off Remote ON/OFF with Externally Set Current

Limit.

Input

Voltage

CONTROL

VUV = IUV x R V

OV = IOV x RLS

@100 VDC = 78%

2 MΩ

MAX

@375 VDC = 38%

MAX

can be an optocoupler

output or can be replaced by a manual switch.

47 kΩ

For R

Figure 27. Active-on Remote ON/OFF with LINE-SENSE and

EXTERNAL CURRENT LIMIT.

LIMIT

ON/OFF

PI-2628-040501

12 kΩ

= 69 %

August 8, 2000

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Page 18

TOP242-249

T ypical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)

2 MΩ

VUV = IUV x R V

OV = IOV x RLS

For RLS = 2 MΩ

= 100 VDC

= 450 VDC

@100 VDC = 78%

MAX

@375 VDC = 38%

MAX

LIMIT

= 12 kΩ

= 69%

For R I

See fig. 55 for other resistor values (R to select different I values

PI-2629-040501

Input

Voltage

CONTROL

12 kΩ

Figure 28. Line-Sensing and Externally Set Current Limit.

QR can be an optocoupler output or can be replaced by a manual switch.

)

LIMIT

Input

Voltage

300 kΩ

CONTROL

47 kΩ

PI-2640-040501

ON/OFF

Figure 29. Active-on Remote ON/OFF.

E 7/01

August 8, 2000

Page 19

Typical Uses of MULTI-FUNCTION (M) Pin

TOP242-249

Input

Voltage

CONTROL

CD S

PI-2508-081199

Figure 30. Three Terminal Operation (MULTI-FUNCTION

Features Disabled).

VUV = RLS x I For Value Shown

= 100 VDC

Input

Voltage

2 MΩ

22 kΩ

CONTROL

6.2 V

VUV = IUV x R V

2 MΩ

Input

Voltage

CONTROL

OV = IOV x RLS

For RLS = 2 MΩ

= 100 VDC

OV =

MAX

Figure 31. Line Sensing for Undervoltage, Over-Voltage and

Line Feed Forward.

450 VDC

@100 VDC = 78% @375 VDC = 38%

PI-2509-040501

Input

2 MΩ

30 kΩ

Voltage

CONTROL

= I

For Values Shown

= 450 VDC

1N4148

OV x RLS

PI-2510-040501

Figure 32. Line Sensing for Under-Voltage Only (Overvoltage

Disabled).

Input

Voltage

CONTROL

For R

= 12 kΩ

I For R

LIMIT

= 25 kΩ

LIMIT

= 69%

= 43%

See fig. 55 for other resistor values (R to select different I

values

LIMIT

PI-2517-040501

Figure 34. Externally Set Current Limit.

PI-2516-040501

Figure 33. Line Sensing for Overvoltage Only (Under-Voltage

Disabled). Maximum Duty Cycle will be reduced at Low Line.

100% @ 100 VDC

LIMIT

RLS2.5 MΩ

)

Input

Voltage

6 kΩ

CONTROL

Figure 35. Current Limit Reduction with Line Voltage.

August 8, 2000

63% @ 300 VDC

LIMIT

PI-2518-040501

7/01

Page 20

TOP242-249

Typical Uses of MULTI-FUNCTION (M) Pin (cont.)

QR can be an optocoupler output or can be replaced by a manual switch.

Input

Voltage

CONTROL

PI-2519-040501

ON/OFF

47 kΩ

Figure 36. Active-on (Fail Safe) Remote ON/OFF.

can be an optocoupler

output or can be replaced by a manual switch.

For R

12 kΩ

LIMIT

= 69 %

25 kΩ

= 43 %

PI-2520-040501

I For R

Voltage

ON/OFF

Input

47 kΩ

CONTROL

Figure 38. Active-on Remote ON/OFF with Externally Set

Current Limit.

QR can be an optocoupler output or can be replaced by a manual switch.

47 kΩ

45 kΩ

CONTROL

PI-2522-040501

Input

Voltage

ON/OFF

Figure 37. Active-off Remote ON/OFF. Maximum Duty Cycle will

be Reduced.

Input

Voltage

ON/OFF

12 kΩ

47 kΩ

CONTROL

can be an optocoupler

output or can be replaced by a manual switch.

24 kΩ

PI-2521-040501

Figure 39. Active-off Remote ON/OFF with Externally Set

Current Limit.

E 7/01

Voltage

Figure 40. Active-off Remote ON/OFF with LINE-SENSE.

August 8, 2000

Input

ON/OFF

47 kΩ

CONTROL

2 MΩ

QR can be an optocoupler output or can be replaced by a manual switch.

For RLS = 2 MΩ V

= 100 VDC

= 450 VDC

PI-2523-040501

Page 21

TOP242-249

Application Examples

A High Efficiency, 30 W, Universal Input Power Supply

The circuit shown in Figure 41 takes advantage of several of the TOPSwitch-GX features to reduce system cost and power supply size and to improve efficiency. This design delivers 30 W at 12 V, from an 85 to 265 VAC input, at an ambient of 50 °C, in an open frame configuration. A nominal efficiency of 80% at full load is achieved using TOP244Y.

The current limit is externally set by resistors R1 and R2 to a value just above the low line operating peak DRAIN current of approximately 70% of the default current limit. This allows use of a smaller transformer core size and/or higher transformer primary inductance for a given output power, reducing TOPSwitch-GX power dissipation, while at the same time avoiding transformer core saturation during startup and output transient conditions. The resistors R1 & R2 provide a signal that reduces the current limit with increasing line voltage, which in turn limits the maximum overload power at high input line voltage. This function in combination with the built-in soft-start feature of TOPSwitch-GX, allows the use of a low cost RCD clamp (R3, C3 and D1) with a higher reflected voltage, by safely limiting the TOPSwitch-GX drain voltage, with adequate

margin under worst case conditions. Resistor R4 provides line sensing, setting UV at 100 VDC and OV at 450 VDC. The extended maximum duty cycle feature of TOPSwitch-GX (guaranteed minimum value of 75% vs. 64% for TOPSwitch-II) allows the use of a smaller input capacitor (C1). The extended maximum duty cycle and the higher reflected voltage possible with the RCD clamp also permit the use of a higher primary to secondary turns ratio for T1 which reduces the peak reverse voltage experienced by the secondary rectifier D8. As a result a 60 V Schottky rectifier can be used for up to 15 V outputs, which greatly improves power supply efficiency. The frequency reduction feature of the TOPSwitch-GX eliminates the need for any dummy loading for regulation at no load and reduces the no load/standby consumption of the power supply. Frequency jitter provides improved margin for conducted EMI meeting the CISPR 22 (FCC B) specification.

Output regulation is achieved by using a simple Zener sense circuit for low cost. The output voltage is determined by the Zener diode (VR2) voltage and the voltage drops across the optocoupler (U2) LED and resistor R6. Resistor R8 provides bias current to Zener VR2 for typical regulation of ±5% at the 12 V output level, over line and load and component variations.

PERFORMANCE SUMMARY Output Power: 30 W

Regulation: ± 4% Efficiency: ≥ 79% Ripple: ≤ 50 mV pk-pk

BR1

600 V

20 mH

CX1

100 nF

250 VAC

3.15 A

C1 68 µF 400 V

4.7 nF 1 kV

UF4005

2 MΩ

1/2 W

4.7 MΩ

1/2 W

TOP244Y

9.09 kΩ

CY1

2.2 nF

68 kΩ

2 W

SXF

TOPSwitch-GX

CONTROL

47 µF

10 V

C14 1 nF

MBR1060

6.8 Ω

R15

150 Ω

1N4148

C10

560 µF

35 V

0.1 µF

C11

560 µF

35 V

150 Ω

3.3 µH

150 Ω U2

LTV817A

VR2 1N5240C 10 V, 2%

C12

220 µF

35 V

PI-2657-040501

12 V @ 2.5 A

RTN

Figure 41. 30 W Power Supply using External Current Limit Programming and Line Sensing for UV and OV.

August 8, 2000

7/01

Page 22

TOP242-249

A High Efficiency, Enclosed, 70 W, Universal Adapter Supply

The circuit shown in figure 42 takes advantage of several of the TOPSwitch-GX features to reduce cost, power supply size and increase efficiency. This design delivers 70 W at 19 V, from an 85 to 265 VAC input, at an ambient of 40 °C, in a small sealed adapter case (4” x 2.15” x 1”). Full load efficiency is 85% at 85 VAC rising to 90% at 230 VAC input.

Due to the thermal environment of a sealed adapter a TOP249Y is used to minimize device dissipation. Resistors R9 and R10 externally program the current limit level to just above the operating peak DRAIN current at full load and low line. This allows the use of a smaller transformer core size without saturation during startup or output load transients. Resistors R9 and R10 also reduce the current limit with increasing line voltage, limiting the maximum overload power at high input line voltage, removing the need for any protection circuitry on the secondary. Resistor R11 implements an under voltage and over voltage sense as well as providing line feed forward for reduced output line frequency ripple. With resistor R11 set at 2 MΩ the power supply does not start operating until the DC rail voltage reaches 100 VDC. On removal of the AC input the UV sense prevents the output glitching as C1 discharges, turning off the TOPSwitch-GX when the output regulation is lost or when the input voltage falls to below 40 V, whichever occurs first. This same value of R11 sets the OV threshold to 450 V. If exceeded, for example during a line surge, TOPSwitch-GX stops switching for the duration of the surge extending the high voltage withstand to 700 V without device damage.

Capacitor C11 has been added in parallel with VR1 to reduce Zener clamp dissipation. With a switching frequency of 132 kHz a PQ26/20 core can be used to provide 70 W. To maximize efficiency, by reducing winding losses, two output windings are used each with their own dual 100 V Schottky rectifier (D2 and D3). The frequency reduction feature of the TOPSwitch-GX eliminates any dummy loading to maintain regulation at no-load and reduces the no-load consumption of the power supply to only 520 mW at 230 VAC input. Frequency jittering provides conducted EMI meeting the CISPR 22 (FCC B) / EN55022B specification, using simple filter components (C7, L2, L3 and C6) even with the output earth grounded.

To regulate the output an optocoupler (U2) is used with a secondary reference sensing the output voltage via a resistor divider (U3, R4, R5, R6). Diode D4 and C15 filter and smooth the output of the bias winding. Capacitor C15 (1uF) prevents the bias voltage from falling during zero to full load transients. Resistor R8 provides filtering of leakage inductance spikes keeping the bias voltage constant even at high output loads. Resistor R7, C9 and C10 together with C5 and R3 provide loop compensation.

Due to the large primary currents, all the small signal control components are connected to a separate source node that is Kelvin connected to the source pin of the TOPSwitch-GX. For improved common mode surge immunity the bias winding common returns directly to the DC bulk capacitor (C1).

820 µH

0.1 µF X2

3.15 A

85-265 VAC

BR1

RS805

8A 600 V

RT1

10 Ω

1.7 A

C13

0.33 µF 400 V

t°

150 µF

400 V

L3 75 µH 2A

0.022 µF 400 V

C12

C11

0.01 µF 400 V

13 MΩ

20.5 kΩ

VR1 P6KE200

D1 UF4006

R11

2 MΩ

1/2 W

CONTROL

R10

CONTROL

SXF

C7 2.2 nF

Y1 Safety

D2 MBR20100

D3 MBR20100

D4 1N4148

TOPSwitch-GX

TOP249Y

0.1 µF 50 V

6.8 Ω

47 µF

16 V

4.7 Ω

PERFORMANCE SUMMARY Output Power: 70 W

Regulation: ± 4% Efficiency: ≥ 84% Ripple: ≤ 120 mV pk-pk No Load Consumption: < 0.52 W @ 230 VAC

C15 1 µF 50 V

820 µF

25 V

820 µF

25 V

PC817A

TL431

All resistors 1/8 W 5% unless otherwise stated.

270 Ω

200 µH

1 kΩ

4.7 nF 50 V

56 kΩ

820 µF

25 V

31.6 kΩ

0.1 µF

4.75 kΩ

C14

0.1 µF 50 V

562 Ω

C10

50 V

19 V @ 3.6 A

RTN

PI-2691-033001

Figure 42. 70 W Power Supply using Current Limit Reduction with Line and Line Sensing for UV and OV.

E 7/01

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Page 23

TOP242-249

A High Efficiency, 250 W, 250 – 380 VDC Input Power Supply

The circuit shown in figure 43 delivers 250 W (48 V @ 5.2 A) at 84% efficiency using a TOP249 from a 250 to 380 VDC input. DC input is shown, as typically at this power level a p.f.c. boost stage would preceed this supply, providing the DC input (C1 is included to provide local decoupling). Flyback topology is still useable at this power level due to the high output voltage, keeping the secondary peak currents low enough so that the output diode and capacitors are reasonably sized.

In this example the TOP249 is at the upper limit of its power capability and the current limit is set to the internal maximum by connecting the X pin to SOURCE. However, line sensing is implemented by connecting a 2 MΩ resistor from the L pin to the DC rail. If the DC input rail rises above 450 VDC, then TOPSwitch-GX will stop switching until the voltage returns to normal, preventing device damage.

Due to the high primary current, a low leakage inductance transformer is essential. Therefore, a sandwich winding with a copper foil secondary was used. Even with this technique the leakage inductance energy is beyond the power capability of a simple Zener clamp. Therefore, R2, R3 and C6 are added in parallel to VR1. These have been sized such that during normal operation very little power is dissipated by VR1, the leakage energy instead being dissipated by R2 and R3. However, VR1

is essential to limit the peak drain voltage during start-up and/ or overload conditions to below the 700 V rating of the TOPSwitch-GX MOSFET.

The secondary is rectifed and smoothed by D2 and C9, C10 and C11. Three capacitors are used to meet the secondary ripple current requirement. Inductor L2 and C12 provide switching noise filtering.

A simple Zener sensing chain regulates the output voltage. The sum of the voltage drop of VR2, VR3 and VR4 plus the LED drop of U2 gives the desired output voltage. Resistor R6 limits LED current and sets overall control loop DC gain. Diode D4 and C14 provide secondary soft-finish, feeding current into the CONTROL pin prior to output regulation and thus ensuring that the output voltage reaches regulation at start-up under low line, full load conditions. Resistor R9 provides a discharge path for C14. Capacitor C13 and R8 provide control loop compensation and are required due to the gain associated with such a high output voltage.

Sufficient heat sinking is required to keep the TOPSwitch-GX device below 110 °C when operating under full load, low line and maximum ambient temperature. Airflow may also be required if a large heat sink area is not acceptable.

+250 - 380 VDC

C1 22 µF 400 V

PERFORMANCE SUMMARY Output Power: 250 W

Line Regulation: ± 1% Load Regulation: ± 5% Efficiency: ≥ 85% Ripple: < 100 mV pk-pk No Load Consumption: ≤ 1.4 W (300 VDC)

VR1

P6KE200

R1 2 MΩ 1/2 W

68 kΩ

2 W

68 kΩ

2 W

BYV26C

2.2 nF Y1

4.7 nF 1 kV

TOPSwitch-GX

TOP249Y

CONTROL

SXF

0.1 µF 50 V

D2 MUR1640CT

560 µF

63 V

D2 1N4148

6.8 Ω C3

47 µF

10 V

C4 1 µF 50 V

C10

560 µF

63 V

C11

560 µF

63 V

LTV817A

100 Ω

C13

150 nF

63 V

VR2 22 V

BZX79B22

VR3 12 V

BZX79B12

VR4 12 V

BZX79B12

All resistor 1/8 W 5% unless otherwise stated.

3 µH 8A

56 Ω

C12

68 µF

63 V

D4 1N4148

C14

22 µF

63 V

48 V @ 5.2 A

RTN

10 kΩ

PI-2692-033001

Figure 43. 250 W, 48 V Power Supply using TOP249.

August 8, 2000

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TOP242-249

Multiple Output, 60 W, 185-265 VAC Input Power Supply

Figure 44 shows a multiple output supply typical for high end set-top boxes or cable decoders containing high capacity hard disks for recording. The supply delivers an output power of 45 W cont./60 W peak (thermally limited) from an input voltage of 185 to 265 VAC. Efficiency at 45 W, 185 VAC is ≥ 75%.

The 3.3 V and 5 V outputs are regulated to ±5% without the need for secondary linear regulators. DC stacking (the secondary winding reference for the other output voltages is connected to the cathode of D10 rather than the anode) is used to minimize the voltage error for the higher voltage outputs.

Due to the high ambient operating temperature requirement typical of a set-top box (60 °C) the TOP246Y is used to reduce conduction losses and minimize heat sink size. Resistor R2 sets the device current limit to 80% of typical to limit overload power. The line sense resistor (R1) protects the TOPSwitch-GX from line surges and transients by sensing when the DC rail voltage rises to above 450 V. In this condition the TOPSwitch-GX stops switching, extending the input voltage withstand to 496 VAC which is ideal for countries with poor power quality. A thermistor (RT1) is used to prevent premature failure of the fuse by limiting the inrush current (due to the relatively large size of C2). An optional MOV (RV1) extends the differential surge protection to 6 kV from 4 kV.

Leakage inductance clamping is provided by VR1, R5 and C5, keeping the DRAIN voltage below 700 V under all conditions. Resistor R5 and capacitor C5 are selected such that VR1 dissipates very little power except during overload conditions. The frequency jittering feature of TOPSwitch-GX allows the circuit shown to meet CISPR22B with simple EMI filtering (C1, L1 and C6) and the output grounded.

The secondaries are rectified and smoothed by D7 to D11, C7, C9, C11, C13, C14, C16 and C17. Diode D11 for the 3.3 V output is a Schottky diode to maximize efficiency. Diode D10 for the 5 V output is a PN type to center the 5 V output at 5 V. The 3.3 V and 5 V output require two capacitors in parallel to meet the ripple current requirement. Switching noise filtering is provided by L2 to L5 and C8, C10, C12, C15 and C18. Resistor R6 prevents peak charging of the lightly loaded 30 V output. The outputs are regulated using a secondary reference (U3). Both the 3.3 V and 5 V outputs are sensed via R11 and R10. Resistor R8 provides bias for U3 and R7 sets the overall DC gain. Resistor R9, C19, R3 and C4 provide loop compensation. A soft-finish capacitor (C20) eliminates output overshoot.

PERFORMANCE SUMMARY Output Power: 45 W Cont./60 W Peak

Regulation:

3.3 V: ± 5% 5 V: ± 5% 12 V: ± 7% 18 V: ± 7% 30 V: ± 8% Efficiency: ≥75% No Load Consumption: 0.6 W

2.2 nF

68 kΩ

2 W

D6 1N4937

2 MΩ 1/2 W

TOPSwitch-GX

CONTROL

1 nF

400 V

0.1 µF 50 V

.R2

9.08 kΩ

20 mH

0.8A

0.1 µF X1

14 mm

3.15 A

185-265 VAC

D1-D4

1N4007 V

RV1

275 V

VR1

P6KE170

C2 68 µF 400 V

TOP246Y

RT1

t°

10 Ω

1.7 A

10 Ω

UF4003

D8 UF5402

D9 UF5402

D10 BYV32-200

D11 MBR1045

1N4148

6.8 Ω C5

47 µF

10 V

47 µF

50 V

330 µF

25 V

C3 1 µF 50 V

C11

390 µF

35 V

C13

1000 µF

25 V

C20

22 µF

10 V

1000 µF

C14

1000 µF

25 V

C17

1000 µF

25 V

C16 25 V

150 Ω

LTV817

3.3 µH 3A

3.3 µH 5A

3.3 kΩ

U3 TL431

C18

220 µF

16 V

1 kΩ

C15

220 µF

165 V

C19

0.1 µF

R11

9.53 kΩ

R12 10 k

C12

100 µF

25 V

C10

100 µF

25 V

R10

15.0 kΩ

10 µF

50 V

30 V @

0.03 A

18 V @

0.5 A

12 V @

0.6 A

5 V @

3.2 A

3.3 V @ 3 A

RTN

PI-2693-033001

Figure 44. 60 W Multiple Output Power Supply using TOP246.

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Page 25

TOP242-249

Processor Controlled Supply Turn On/Off

A low cost momentary contact switch can be used to turn the TOPSwitch-GX power on and off under microprocessor control that may be required in some applications such as printers. The low power remote off feature allows an elegant implementation of this function with very few external components as shown in Figure 45. Whenever the push button momentary contact switch P1 is closed by the user, the optocoupler U3 is activated to inform the microprocessor of this action. Initially, when the power supply is off (M pin is floating), closing of P1 turns the power supply on by shorting the M pin of the TOPSwitch-GX to SOURCE through a diode (remote on). When the secondary output voltage VCC is established, the microprocessor comes alive and recognizes that the switch P1 is closed through the switch status input that is driven by the optocoupler U3 output. The microprocessor then sends a power supply control signal to hold the power supply in the on-state through the optocoupler U4. If the user presses the switch P1 again to command a turn off, the microprocessor detects this through the optocoupler U3 and initiates a shutdown procedure that is product specific. For example, in the case of the inkjet printer, the shutdown procedure may include safely parking the print heads in the storage

position. In the case of products with a disk drive, the shutdown procedure may include saving data or settings to the disk. After the shutdown procedure is complete, when it is safe to turn off the power supply, the microprocessor releases the M pin by turning the optocoupler U4 off. If the manual switch and the optocouplers U3 and U4 are not located close to the M pin, a capacitor CM may be needed to prevent noise coupling to the pin when it is open.

The power supply could also be turned on remotely through a local area network or a parallel or serial port by driving the optocoupler U4 input LED with a logic signal. Sometimes it is easier to send a train of logic pulses through a cable (due to AC coupling of cable, for example) instead of a DC logic level as a wake up signal. In this case, a simple RC filter can be used to generate a DC level to drive U4 (not shown in Figure 45). This remote on feature can be used to wake up peripherals such as printers, scanners, external modems, disk drives, etc., as needed from a computer. Peripherals are usually designed to turn off automatically if they are not being used for a period of time, to save power.

High Voltage

DC Input

27 kΩ

1N4148

1 nF

TOPSwitch-GX

CONTROL

Figure 45. Remote ON/OFF using Microcontroller.

(+5 V)

External Wake-up

Signal

Power Supply

ON/OFF

Control

6.8 kΩ

1N4148

6.8 kΩ

RETURN

PI-2561-033001

MICRO

100 kΩ

47 µF

LTV817A

PROCESSOR/ CONTROLLER

LOGIC

INPUT

P1 Switch

Status

LOGIC

OUTPUT

LTV817A

August 8, 2000

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Page 26

TOP242-249

In addition to using a minimum number of components, TOPSwitch-GX provides many technical advantages in this type of application:

1. Extremely low power consumption in the off mode: 80 mW typical at 110 VAC and 160 mW typical at 230 VAC. This is because in the remote/off mode the TOPSwitch-GX consumes very little power, and the external circuitry does not consume any current (either M, L or X pin is open) from the high voltage DC input.

2. A very low cost, low voltage/current, momentary contact switch can be used.

3. No debouncing circuitry for the momentary switch is required. During turn-on, the start-up time of the power supply (typically 10 to 20 ms) plus the microprocessor initiation time act as a debouncing filter, allowing a turn-on only if the switch is depressed firmly for at least the above delay time. During turn-off, the microprocessor initiates the shutdown

sequence when it detects the first closure of the switch, and subsequent bouncing of the switch has no effect. If necessary, the microprocessor could implement the switch debouncing in software during turn-off, or a filter capacitor can be used at the switch status input.

4. No external current limiting circuitry is needed for the operation of the U4 optocoupler output due to internal limiting of M pin current.

5. No high voltage resistors to the input DC voltage rail are required to power the external circuitry in the primary. Even the LED current for U3 can be derived from the CONTROL pin. This not only saves components and simplifies layout, but also eliminates the power loss associated with the high voltage resistors in both on and off states.

6. Robust design: There is no on/off latch that can be accidentally triggered by transients. Instead, the power supply is held in the on-state through the secondary side microprocessor.

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Page 27

Key Application Considerations

TOP242-249

TOPSwitch-II

Table 4 compares the features and performance differences between TOPSwitch-GX and TOPSwitch-II. Many of the new

vs.

TOPSwitch-GX

Other features increase the robustness of design allowing cost savings in the transformer and other power components.

features eliminate the need for additional discrete components.

Function

TOPSwitch-II TOPSwitch-GX

Figures

TOPSwitch-GX

Advantages

Soft-Start N/A* 10 ms • Limits peak current and voltage

component stresses during start-up

• Eliminates external components used for soft-start in most applications

• Reduces or eliminates output overshoot

External Current Limit N/A* Programmable 11,20,21, • Smaller transformer

100% to 30% of 24,25,27, • Higher efficiency default current 28,34,35, • Allows power limiting (constant overlimit 38,39 load power independent of line

voltage

• Allows use of larger device for lower losses, higher efficiency and smaller heatsink

MAX

67% 78% 7 • Smaller input cap (wider dynamic

range)

• Higher power capability (when used with RCD clamp for large VOR)

• Allows use of Schottky secondary rectifier diode for up to 15 V output for high efficiency

Line Feed Forward with N/A* 78% to 38% 7,11,17, • Rejects line ripple DC

Reduction 26,27,28,

MAX

31,40

Line OV Shutdown N/A* Single resistor 11,17,19, • Increases voltage withstand cap-

programmable 26,27,28, ability against line surge

31,33,40

Line UV Detection N/A* Single resistor 11,17,18, • Prevents auto-restart glitches

programmable 26,27,28, during power down

31,32,40

Switching Frequency 100 kHz ±10% 132 kHz ±6% 13,15 • Smaller transformer

• Below start of conducted EMI limits

Switching Frequency N/A* 66 kHz ±7% 14,15 • Lower losses when using RC and Option (Y and R RCD snubber for noise reduction in Packages) video applications

• Allows for higher efficiency in standby mode

• Lower EMI (second harmonic below 150 kHz)

Frequency Jitter N/A* ±4 kHz@132 kHz 9,46 • Reduces conducted EMI

±2 kHz@66 kHz

Frequency Reduction N/A* At a Duty Cycle 7 • Zero load regulation without dummy

below 10% load

• Low power consumption at no load

Table 4. Comparison Between TOPSwitch-II and TOPSwitch-GX. (continued on next page) *Not available

August 8, 2000

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Page 28

TOP242-249

Function

Remote ON/OFF N/A* Single transistor 11, 22, • Fast on/off (cycle by cycle)

Synchronization N/A* Single transistor • Synchronization to external lower

Thermal Shutdown 125 °C min. Hysteretic 130 °C • Automatic recovery from thermal

Current Limit Tolerance ±10% (@25 °C) ±7% (@25 °C) • 10% higher power capability due to

DRAIN DIP 0.037" / 0.94 mm 0.137" / 3.48 mm • Greater immunity to arcing as a Creepage SMD 0.037" / 0.94 mm 0.137" / 3.48 mm result of build-up of dust, debris and at Package TO-220 0.046" / 1.17 mm 0.068" / 1.73 mm other contaminants DRAIN Creepage at 0.045" / 1.14 mm 0.113" / 2.87 mm • Preformed leads accommodate PCB for Y and R (R Package N/A*) (preformed leads) large creepage for PCB layout Packages • Easier to meet Safety (UL/VDE)

TOPSwitch-II TOPSwitch-GX

or optocoupler 23, 24, • Active-on or active-off control interface or manual 25, 26, • Low consumption in remote off state switch 27, 29, • Active-on control for fail-safe

or optocoupler frequency signal interface • Starts new switching cycle on

Latched min. Shutdown (with fault

75 °C hysteresis) • Large hysteresis prevents circuit

-8% (0 °C to100 °C) -4% (0 °C to 100 °C) tighter tolerance

Figures

36, 37, • Eliminates expensive in-line on/off 38, 39, switch 40 • Allows processor controlled turn

TOPSwitch-GX

on/off

• Permits shutdown/wake-up of peripherals via LAN or parallel port

demand

board overheating

Advantages

Table 4 (cont). Comparison Between TOPSwitch-II and TOPSwitch-GX. *Not available

TOPSwitch-FX

Table 5 compares the features and performance differences between TOPSwitch-GX and TOPSwitch-FX. Many of the new features eliminate the need for additional discrete components.

Function

Light Load Operation Cycle skipping Frequency and Duty Cycle • Improves light load efficiency

Line Sensing/Externally Line sensing and Line sensing and externally • Additional design flexibility allows all Set Current Limit externally set set current limit possible features to be used simultaneously (Y and R Packages) current limit simultaneously

Current Limit 100-40% 100-30% • Minimizes transformer core size Programming in highly continuous designs Range

Table 5. Comparison Between TOPSwitch-FX and TOPSwitch-GX. (continued on next page)

vs.

TOPSwitch-GX

TOPSwitch-FX TOPSwitch-GX TOPSwitch-GX

mutually (functions split onto exclusive (M pin) L and X pins)

Other features increase the robustness of design allowing cost savings in the transformer and other power components.

Advantages

reduction • Reduces no-load consumption

E 7/01

August 8, 2000

Page 29

TOP242-249

Function

TOPSwitch-FX TOPSwitch-GX TOPSwitch-GX

Advantages

P/G Package Current Identical to Y TOP243P or G and • Matches device current limit to Limits packages TOP244P or G internal package dissipation capability

current limits reduced • Allows more continuous design to

lower device dissipation (lower RMS currents)

Y/R Package Current 100% 90% (for equivalent R

) • Minimizes transformer core size

DS (ON)

Limits (R package N/A*) • Optimizes efficiency for most

applications

Thermal Shutdown 125 °C min. 130 °C min. 75 °C • Allows higher output powers in

70 °C hysteresis hysteresis high ambient temperature

applications

Maximum Duty Cycle 90 µA 60 µA • Reduces output line frequency Reduction Threshold ripple at low line

• D

reduction optimized for

MAX

forward design

Line Under-Voltage N/A* 40% of positive (turn-on) • Provides a well defined turn-off Negative (turn-off) threshold threshold as the line voltage falls Threshold

Soft-Start 10 ms (duty cycle) 10 ms (duty cycle + current • Gradually increasing current limit

limit) in addition to duty cycle during soft-

start further reduces peak current and voltage

• Further reduces component stresses during start up

Table 5 (cont). Comparison Between TOPSwitch-FX and TOPSwitch-GX. *Not available

TOPSwitch-GX

Design Considerations

applications where higher efficiency is needed or minimal heat sinking is available.

Power Table

Datasheet power table represents the maximum practical continuous output power based on the following conditions: TOP242 to TOP246: 12 V output, Schottky output diode, 150 V reflected voltage (VOR) and efficiency estimates from curves contained in application note AN-29. TOP247 to TOP249: Higher output voltages used with a maximum output current of 6 A.

Input Capacitor

The input capacitor must be chosen to provide the minimum DC voltage required for the TOPSwitch-GX converter to maintain regulation at the lowest specified input voltage and maximum output power. Since TOPSwitch-GX has a higher DC TOPSwitch-II, it is possible to use a smaller input capacitor. For TOPSwitch-GX, a capacitance of 2 µF per watt is possible

for universal input with an appropriately designed transformer. For all devices a 100 VDC minimum for 85-265 VAC and 250 VDC minimum for 230 VDC are assumed and sufficient heat sinking to keep device temperature ≤ 100 °C. Power levels shown in the power table for the R package device assume

6.45 cm2 of 610 g/m2 copper heat sink area in an enclosed adapter, or 19.4 cm2 in an open frame.

Primary Clamp and Output Reflected Voltage V

A primary clamp is necessary to limit the peak TOPSwitch-GX

drain to source voltage. A Zener clamp requires few parts and

takes up little board space. For good efficiency, the clamp

Zener should be selected to be at least 1.5 times the output

reflected voltage V

TOPSwitch-GX Selection

Selecting the optimum TOPSwitch-GX depends upon required maximum output power, efficiency, heat sinking constraints and cost goals. With the option to externally reduce current limit, a larger TOPSwitch-GX may be used for lower power

time short. When using a Zener clamp in a universal input

application, a VOR of less than 135 V is recommended to allow

for the absolute tolerances and temperature variations of the

Zener. This will ensure efficient operation of the clamp circuit

and will also keep the maximum drain voltage below the rated

breakdown voltage of the TOPSwitch-GX MOSFET.

MAX

as this keeps the leakage spike conduction

than

August 8, 2000

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Page 30

TOP242-249

A high VOR is required to take full advantage of the wider DC

MAX

of TOPSwitch-GX. An RCD clamp provides tighter clamp voltage tolerance than a Zener clamp and allows a V

as high as 150 V. RCD clamp dissipation can be minimized by reducing the external current limit as a function of input line voltage (see Figure 21 and 35). The RCD clamp is more cost effective than the Zener clamp but requires more careful design (see quick design checklist).

Output Diode

The output diode is selected for peak inverse voltage, output current, and thermal conditions in the application (including heatsinking, air circulation, etc.). The higher DC

MAX

of TOPSwitch-GX along with an appropriate transformer turns ratio can allow the use of a 60 V Schoktty diode for higher efficiency on output voltages as high as 15 V (see Figure 41. A 12 V, 30 W design using a 60 V Schottky for the output diode).

Bias Winding Capacitor

Due to the low frequency operation at no-load a 1µF bias winding capacitor is recommended.

Soft-Start

Generally a power supply experiences maximum stress at startup before the feedback loop achieves regulation. For a period of 10 ms the on-chip soft-start linearly increases the duty cycle from zero to the default DC

at turn on. In addition, the

MAX

primary current limit increases from 85% to 100% over the same period. This causes the output voltage to rise in an orderly manner allowing time for the feedback loop to take control of the duty cycle. This reduces the stress on the TOPSwitch-GX MOSFET, clamp circuit and output diode(s), and helps prevent transformer saturation during start-up. Also soft-start limits the amount of output voltage overshoot, and in many applications eliminates the need for a soft-finish capacitor.

EMI

The frequency jitter feature modulates the switching frequency over a narrow band as a means to reduce conducted EMI peaks associated with the harmonics of the fundamental switching frequency. This is particularly beneficial for average detection mode. As can be seen in Figure 46, the benefits of jitter increase with the order of the switching harmonic due to an increase in frequency deviation.

The FREQUENCY pin of TOPSwitch-GX offers a switching frequency option of 132 kHz or 66 kHz. In applications that require heavy snubbers on the drain node for reducing high frequency radiated noise (for example, video noise sensitive applications such as VCR, DVD, monitor, TV, etc.), operating at 66 kHz will reduce snubber loss resulting in better efficiency. Also, in applications where transformer size is not a concern, use of the 66 kHz option will provide lower EMI and higher efficiency. Note that the second harmonic of 66 kHz is still below 150 kHz, above which the conducted EMI specifications get much tighter.

E 7/01

August 8, 2000

For 10 W or below, it is possible to use a simple inductor in place of a more costly AC input common mode choke to meet worldwide conducted EMI limits.

Transformer Design

It is recommended that the transformer be designed for maximum operating flux density of 3000 Gauss and a peak flux density of 4200 Gauss at maximum current limit. The turns ratio should be chosen for a reflected voltage (VOR) no greater than 135 V when using a Zener clamp, or 150 V (max) when using RCD clamp with current limit reduction with line voltage (overload protection).

For designs where operating current is significantly lower than the default current limit, it is recommended to use an externally set current limit close to the operating peak current to reduce peak flux density and peak power (see Figure 20 and 34). In most applications, the tighter current limit tolerance, higher

80 70 60 50 40 30

-10

Amplitude (dBµV)

-10

-20

0.15 1 10 30

Figure 46a. TOPSwitch-II Full Range EMI Scan

(100 kHz, no jitter)

80 70 60

50 40 30 20

-10

Amplitude (dBµV)

-10

-20

0.15 1 10 30

Figure 46b. TOPSwitch-GX Full Range EMI Scan (132 kHz,

with jitter) with Identical Circuitry and Conditions.

TOPSwitch-II (no jitter)

EN55022B (QP) EN55022B (AV)

Frequency (MHz)

TOPSwitch-GX (with jitter)

EN55022B (QP) EN55022B (AV)

Frequency (MHz)

PI-2576-010600

PI-2577-010600

Page 31

TOP242-249

switching frequency and soft-start features of TOPSwitch-GX contribute to a smaller transformer when compared to

TOPSwitch-II.

Standby Consumption

Frequency reduction can significantly reduce power loss at light or no load, especially when a Zener clamp is used. For very low secondary power consumption use a TL431 regulator for feedback control. Alternately, switching losses can be significantly reduced by changing from 132 kHz in normal operation to 66 kHz under light load conditions.

TOPSwitch-GX

As TOPSwitch-GX has additional pins and operates at much higher power levels compared to previous TOPSwitch families, the following guidelines should be carefully followed.

Primary Side Connections

Use a single point (Kelvin) connection at the negative terminal of the input filter capacitor for TOPSwitch-GX source pin and bias winding return. This improves surge capabilities by returning surge currents from the bias winding directly to the input filter capacitor.

The CONTROL pin bypass capacitor should be located as close as possible to the SOURCE and CONTROL pins and its SOURCE connection trace should not be shared by the main MOSFET switching currents. All SOURCE pin referenced components connected to the MULTI-FUNCTION, LINESENSE or EXTERNAL CURRENT LIMIT pins should also be located closely between their respective pin and SOURCE. Once again the SOURCE connection trace of these components should not be shared by the main MOSFET switching currents. It is very critical that SOURCE pin switching currents are returned to the input capacitor negative terminal through a seperate trace that is not shared by the components connected to CONTROL, MULTI-FUNCTION, LINE-SENSE or EXTERNAL CURRENT LIMIT pins. This is because the SOURCE pin is also the controller ground reference pin.

Any traces to the M, L or X pins should be kept as short as possible and away from the DRAIN trace to prevent noise coupling. LINE-SENSE resistor (R1 in figures 47-49) should be located close to the M or L pin to minimize the trace length on the M or L pin side.

Layout Considerations

Y-Capacitor

The Y-capacitor should be connected close to the secondary output return pin(s) and the positive primary DC input pin of the transformer.

Heat Sinking

The tab of the Y package (TO-220) is internally electrically tied to the SOURCE pin. To avoid circulating currents, a heat sink attached to the tab should not be electrically tied to any primary ground/source nodes on the PC board.

When using a P (DIP-8), G (SMD-8) or R (TO-263) package, a copper area underneath the package connected to the SOURCE pins will act as an effective heat sink. On double sided boards (Figure 49), top side and bottom side areas connected with vias can be used to increase the effective heat sinking area.

In addition, sufficient copper area should be provided at the anode and cathode leads of the output diode(s) for heat sinking.

In Figures 47, 48 and 49 a narrow trace is shown between the output rectifier and output filter capacitor. This trace acts as a thermal relief between the rectifier and filter capacitor to prevent excessive heating of the capacitor.

Quick Design Checklist

As with any power supply design, all TOPSwitch-GX designs should be verified on the bench to make sure that components specifications are not exceeded under worst case conditions. The following minimum set of tests is strongly recommended:

1. Maximum drain voltage – Verify that peak VDS does not exceed 675 V at highest input voltage and maximum overload output power. Maximum overload output power occurs when the output is overloaded to a level just before the power supply goes into auto-restart (loss of regulation).

2. Maximum drain current – At maximum ambient temperature, maximum input voltage and maximum output load, verify drain current waveforms at start-up for any signs of transformer saturation and excessive leading edge current spikes. TOPSwitch-GX has a leading edge blanking time of 220 ns to prevent premature termination of the on-cycle. Verify that the leading edge current spike is below the allowed current limit envelope (see Figure 52) for the drain current waveform at the end of the 220 ns blanking period.

In addition to the 47 µF CONTROL pin capacitor, a high frequency bypass capacitor in parallel may be used for better noise immunity. The feedback optocoupler output should also be located close to the CONTROL and SOURCE pins of

TOPSwitch-GX.

3. Thermal check – At maximum output power, minimum input voltage and maximum ambient temperature, verify that temperature specifications are not exceeded for TOPSwitch-GX, transformer, output diodes and output capacitors. Enough thermal margin should be allowed for

August 8, 2000

7/01

Page 32

TOP242-249

Input Filter Capacitor

PRI

BIAS

PRI

TOP VIEW

TOPSwitch-GX

BIAS

Figure 47. Layout Considerations for TOPSwitch-GX using P or G Packages.

Safety Spacing

Y1-

Capacitor

r a n s

f o

Opto-

coupler

SEC

Maximize hatched copper areas ( ) for optimum heat sinking

Output Rectifier Output Filter Capacitor

Out

PI-2670-042301

Input Filter Capacitor

TOPSwitch-GX

TOP VIEW

Heat Sink

Figure 48. Layout Considerations for TOPSwitch-GX using Y Package.

Safety Spacing

Y1-

Capacitor

r a n s

Opto-

coupler

Maximize hatched copper areas ( ) for optimum heat sinking

Output Rectifier Output Filter Capacitor

SEC

Out

PI-2669-042301

E 7/01

August 8, 2000

Page 33

TOP242-249

Solder Side Component Side

TOP VIEW

R1a - 1c

TOPSwitch-GX

Input Filter

Capacitor

Safety Spacing

Y1-

Capacitor

PRI

BIAS

a n s

Opto-

coupler

Output Filter Capacitors

SEC

f r

Out

Maximize hatched copper areas( ) for optimum heat sinking

PI-2734-043001

Figure 49. Layout Considerations for TOPSwitch-GX using R Package.

the part-to-part variation of the R

of TOPSwitch-GX as

DS(ON)

specified in the data sheet. The margin required can either be calculated from the tolerances or it can be accounted for by connecting an external resistance in series with the DRAIN pin and attached to the same heatsink, having a resistance value that is equal to the difference between the measured R

of the device under test and the worst case

DS(ON)

maximum specification.

Design Tools

Up to date information on design tools can be found at the Power Integrations Web site: www.powerint.com

August 8, 2000

7/01

Page 34

TOP242-249

ABSOLUTE MAXIMUM RATINGS

DRAIN Voltage ............................................ -0.3 to 700 V

DRAIN Peak Current: TOP242 ...............................0.72 A

TOP243 ...............................1.44 A

TOP244 ...............................2.16 A

TOP245 ...............................2.88 A

TOP246 ...............................4.32 A

TOP247 ...............................5.76 A

TOP248 ...............................7.20 A

TOP249 ...............................8.64 A

CONTROL Voltage .......................................... -0.3 to 9 V

CONTROL Current ...............................................100 mA

THERMAL IMPEDANCE

Thermal Impedance: Y Package (θJA) (θJC) P or G Package:

(θJA) ......45 °C/W

(θJC)

(1)

............... 70 °C/W

(2)

................ 2 °C/W

(3)

(5)

......................... 11 °C/W

; 35 °C/W

(1)

LINE SENSE Pin Voltage ................................ -0.3 to 9 V

CURRENT LIMIT Pin Voltage ..................... -0.3 to 4.5 V

MULTI-FUNCTION Pin Voltage .................... -0.3 to 9 V

FREQUENCY Pin Voltage............................... -0.3 to 9 V

Storage Temperature .....................................-65 to 150 °C

Operating Junction Temperature Lead Temperature

(3)

............................................... 260 °C

(2)

...............-40 to 150 °C

Notes:

1. All voltages referenced to SOURCE, TA = 25 °C.

2. Normally limited by internal circuitry.

3. 1/16" from case for 5 seconds.

Notes:

1. Free standing with no heatsink.

2. Measured at the back surface of tab.

(4)

3. Soldered to 0.36 sq. inch (232 mm2), 2oz. (610 gm/m2) copper clad.

4. Soldered to 1 sq. inch (645 mm2), 2oz. (610 gm/m2) copper clad.

5. Measured on the SOURCE pin close to plastic interface.

Parameter

Symbol

CONTROL FUNCTIONS

Switching Frequency (average)

Duty Cycle at ONSET of Fre-

quency Reduction Switching

Frequency near

OSC (DMIN)

0% Duty Cycle Frequency Jitter

Deviation Frequency Jitter

Modulation Rate Maximum Duty

Cycle

OSC

(ONSET)

∆f

MAX

Conditions

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V; TJ = -40 to 125 °C

= 3 mA;

TJ = 25 °C

IC = I

CD1

FREQUENCY Pin

Connected to SOURCE

FREQUENCY Pin

Connected to CONTROL

132 kHz Operation

66 kHz Operation

132 kHz Operation

66 kHz Operation

IL ≤ I

L (DC)

or IM ≤ I

IL or IM = 190 µA

M(DC)

Min Typ Max

124 132 140

61.5 66 70.5

30 15

± 4 ± 2

250

75 78 83 28 38 50

Units

kHz

Soft Start Time

7/01

SOFT

August 8, 2000

TJ = 25 °C; DC

MIN to DCMAX

10 15

Page 35

Parameter

Symbol

SOURCE = 0 V

CONTROL FUNCTIONS (cont.)

Conditions

(Unless Otherwise Specified)

See Figure 53

; T

= -40 to 125 °C

TOP242-249

Min Typ Max

Units

PWM Gain IC = 4 mA; T

PWM Gain Temperature Drift

External Bias Current

reg

See Note A

See Figure 7

CONTROL Current at 0%

(OFF)

TJ = 25 °C

Duty Cycle Dynamic

Impedance

IC = 4 mA; TJ = 25 °C

See Figure 51

Dynamic Impedance Temperature Drift

Control Pin Internal Filter Pole

SHUTDOWN/AUTO-RESTART

Control Pin Charging Current

C (CH)

TJ = 25 °C

= 25 °C -28 -23 -18 %/mA

%/mA/°C

Ω

%/°C

kHz

TOP242-245 TOP246-249

VC = 0 V VC = 5 V

-0.01

1.2 2.0 3.0

1.6 2.6 4.0

6.0 7.0

6.6 8.0

10 15 22

0.18

-5.0 -3.5 -2.0

-3.0 -1.8 -0.6

Charging Current Temperature Drift

Auto-restart Upper Threshold Voltage

Auto-restart Lower Threshold Voltage

Auto-restart Hysteresis Voltage

Auto-restart Duty Cycle

Auto-restart Frequency

C(AR)U

C(AR)L

C(AR)hyst

(AR)

See Note A

0.5

5.8

4.5 4.8 5.1

0.8 1.0

1.0

August 8, 2000

%/°C

7/01

Page 36

TOP242-249

Conditions

Parameter

Symbol

MULTI-FUNCTION (M), LINE-SENSE (L) AND EXTERNAL CURRENT LIMIT (X) INPUTS

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

= -40 to 125 °C

Min Typ Max

Units

Line Under-Voltage Threshold Current and Hysteresis (M or L Pin)

Line Over-Voltage or Remote ON/ OFF Threshold Current and Hysteresis (M or L Pin)

L Pin Voltage Threshold

Remote ON/OFF Negative Threshold Current and Hysteresis (M or X Pin)

L or M Pin Short Circuit Current

X or M Pin Short Circuit Current

L or M Pin Voltage (Positive Current)

X Pin Voltage (Negative Current)

M Pin Voltage (Negative Current)

L(TH)

REM (N)

(SC)

M (SC)

(SC)

M (SC)

VL, V

Threshold

TJ = 25 °C

Hysteresis

Threshold

TJ = 25 °C

Hysteresis

Threshold

TJ = 25 °C

Hysteresis

VX, VM = 0 V

VL, VM = V

lL or lM = 50 µA

Normal Mode

Auto-restart Mode

lL or lM = 225 µA

lX = -50 µA

lX = -150 µA

lM = -50 µA

lM = -150 µA

44 50 54

210 225 240

0.5 1.0 1.6

-35 -27 -20

300 400 520

-300 -240 -180

-110 -90 -70

1.90 2.50 3.00

2.30 2.90 3.30

1.26 1.33 1.40

1.18 1.24 1.30

1.24 1.31 1.39

1.13 1.19 1.25

µA

Maximum Duty Cycle Reduction Onset Threshold Current

Maximum Duty Cycle Reduction Slope

Remote OFF DRAIN Supply Current

E 7/01

August 8, 2000

L (DC)

M (DC)

D(RMT)

See Figure 70 V

DRAIN

TJ = 25 °C

IL > I

= 150 V

TJ = 25 °C

or IM > I

L(DC)

X, L or M Pin

Floating

L or M Pin Shorted

to CONTROL

M (DC)

40 60 75

0.25

0.6 1.0

1.0 1.6

µA

%/µA

Page 37

TOP242-249

Conditions

Parameter

Symbol

MULTI-FUNCTION (M), LINE-SENSE (L) AND CURRENT LIMIT (I) INPUTS (cont)

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V; TJ = -40 to 125 °C

Min Typ Max

Units

Remote ON Delay

Remote OFF Setup Time

FREQUENCY INPUT

FREQUENCY Pin Threshold Voltage

FREQUENCY Pin Input Current

CIRCUIT PROTECTION

Self Protection Current Limit

Initial Current Limit

Leading Edge Blanking Time

R(ON)

R(OFF)

LIMIT

INIT

LEB

TOP242 P/G TOP242 Y/R TJ= 25 °C

TOP243 P/G TJ= 25 °C

TOP243 Y/R TJ= 25 °C

TOP244 P/G TJ= 25 °C

TOP244 Y/R TJ= 25 °C

TOP245 Y/R TJ= 25 °C

TOP246 Y/R TJ= 25 °C

TOP247 Y/R TJ= 25 °C

TOP248 Y/R TJ= 25 °C

TOP249 Y/R TJ= 25 °C

From Remote On to Drain Turn-On

See Note B

Minimum Time Before Drain Turn-On

to Disable Cycle

See Note B

VF = V

Internal; di/dt=90 mA/µs

See Note C

Internal; di/dt=150 mA/µs

See Note C

Internal; di/dt=180 mA/µs

See Note C

Internal; di/dt=200 mA/µs

See Note C

Internal; di/dt=270 mA/µs

See Note C

Internal; di/dt=360 mA/µs

See Note C

Internal; di/dt=540 mA/µs

See Note C

Internal; di/dt=720 mA/µs

See Note C

Internal; di/dt=900 mA/µs

See Note C

Internal;di/dt=1080 mA/µs

See Note C

≤ 85 VAC

See

Note B

See Fig. 52

TJ = 25 °C

(Rectified Line Input)

265 VAC

(Rectified Line Input)

IC = 4 mA

2.5 µs

2.9 V

10 40 100 µA

0.418 0.45 0.481

0.697 0.75 0.802

0.837 0.90 0.963

0.930 1.00 1.070

1.256 1.35 1.445

1.674 1.80 1.926

2.511 2.70 2.889

3.348 3.60 3.852

4.185 4.50 4.815

5.022 5.40 5.778

0.75 x

LIMIT(MIN)

0.6 x

LIMIT(MIN)

220

August 8, 2000

7/01

Page 38

TOP242-249

Conditions

Parameter

Symbol

CIRCUIT PROTECTION (cont)

Current Limit Delay

IL(D)

Thermal Shutdown Temperature

Thermal Shutdown Hysteresis

Power-up Reset Threshold Voltage

C(RESET)

OUTPUT

ON-State Resistance

Off-State Current

DS(ON)

DSS

(Unless Otherwise Specified)

See Figure 53

; T

SOURCE = 0 V

Figure 53, S1 Open

TOP242

ID = 50 mA

TOP243

ID = 100 mA

TOP244

ID = 150 mA

TOP245

ID = 200 mA

TOP246

ID = 300 mA

TOP247

ID = 400 mA

TOP248

ID = 500 mA

TOP249

ID = 600 mA

VL, VM = Floating; IC = 4mA

VDS = 560 V; TJ = 125 °C

= -40 to 125 °C

IC = 4 mA

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

TJ = 25 °C

TJ = 100 °C

Min Typ Max

100

130 140 150

1.75 3.0 4.25

15.6 18.0

25.7 30.0

7.80 9.00

12.9 15.0

5.20 6.00

8.60 10.0

3.90 4.50

6.45 7.50

2.60 3.00

4.30 5.00

1.95 2.25

3.22 3.75

1.56 1.80

2.58 3.00

1.30 1.50

2.15 2.50 400 µA

Units

°C

Ω

Breakdown Voltage

Rise Time

Fall Time

7/01

DSS

August 8, 2000

VL, VM = Floating; IC = 4mA

ID = 100 µA; TJ = 25 °C

Measured in a Typical

Flyback Converter Application

700 V

100 ns

50 ns

Page 39

Conditions

TOP242-249

Parameter

Symbol

(Unless Otherwise Specified)

See Figure 53

SOURCE = 0 V

; T

= -40 to 125 °C

Min Typ Max

SUPPLY VOLTAGE CHARACTERISTICS

DRAIN Supply Voltage

Shunt Regulator Voltage

C(SHUNT)

Shunt Regulator Temperature Drift

Output

MOSFET Enabled

VL, VM = 0 V

Control Supply/

CD1

Discharge Current

CD2

NOTES:

A. For specifications with negative values, a negative temperature coefficient corresponds to an increase in

magnitude with increasing temperature, and a positive temperature coefficient corresponds to a decrease in magnitude with increasing temperature.

See Note D

IC = 4 mA

TOP 242-245 TOP 246-249

Output

MOSFET Disabled

VL, VM = 0 V

5.60 5.85 6.10

±50

1.0 1.6 2.5

1.2 2.2 3.2

0.3 0.6 1.3

Units

ppm/°C

B. Guaranteed by characterization. Not tested in production. C.For externally adjusted current limit values, please refer to Figure 55 (Current Limit vs. External Current Limit

Resistance) in the Typical Performance Characteristics section.

D.It is possible to start up and operate TOPSwitch-GX at DRAIN voltages well below 36 V. However, the

CONTROL pin charging current is reduced, which affects start-up time, auto-restart frequency, and auto-restart duty cycle. Refer to Figure 67, the characteristic graph on CONTROL pin charge current (IC) vs. DRAIN voltage for low voltage operation characteristics.

August 8, 2000

7/01

Page 40

TOP242-249

90%

DRAIN

VOLTAGE

Figure 50. Duty Cycle Measurement.

120

100

Dynamic

Impedance

CONTROL Pin Current (mA)

0246810

CONTROL Pin Voltage (V)

Slope

0 V

PI-1939-091996

10%

D =

PI-2039-033001

(Blanking Time)

1.3

LEB

1.2

1.1

1.0

0.9

0.8

0.7

0.6

INIT(MIN)

@ 85 VAC

@ 265 VAC

0.5

0.4

0.3

0.2

DRAIN Current (normalized)

0.1

LIMIT(MAX)

LIMIT(MIN)

@ 25 °C

012 6 83

45 7

Time (µs)

PI-2022-033001

Figure 51. CONTROL Pin I-V Characteristic.

Figure 52. Drain Current Operating Envelope.

Y or R Package (X and L Pin) P or G Package (M Pin)

470 Ω

5 W

0-100 kΩ

5-50 V

40 V

470 Ω

CONTROL

0-15 V

0.1 µF47 µF

NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements.

2. For P and G packages, short all SOURCE pins together.

0-60 kΩ

Figure 53. TOPSwitch-GX General Test Circuit.

E 7/01

August 8, 2000

0-100 kΩ

5-50 V

0-60 kΩ

TOPSwitch-GX

SFX

PI-2631-033001

Page 41

TOP242-249

BENCH TEST PRECAUTIONS FOR EVALUATION OF ELECTRICAL CHARACTERISTICS

The following precautions should be followed when testing TOPSwitch-GX by itself outside of a power supply. The schematic shown in Figure 53 is suggested for laboratory testing of TOPSwitch-GX.

When the DRAIN pin supply is turned on, the part will be in the auto-restart mode. The CONTROL pin voltage will be oscillating at a low frequency between 4.8 and 5.8 V and the drain is turned on every eighth cycle of the CONTROL pin oscillation. If the CONTROL pin power supply is turned on while in this auto-

Typical Performance Characteristics

1.1

1.0

0.9

0.8

0.7

0.6

0.5

Current Limit (A)

0.4

0.3

0.2

-250 -200 -150 -100 -50

Figure 54. Current Limit vs. MULTI-FUNCTION Pin Current.

restart mode, there is only a 12.5% chance that the CONTROL pin oscillation will be in the correct state (drain active state) so that the continuous drain voltage waveform may be observed. It is recommended that the V

power supply be turned on first

and the DRAIN pin power supply second if continuous drain voltage waveforms are to be observed. The 12.5% chance of being in the correct state is due to the divide-by-8 counter. Temporarily shorting the CONTROL pin to the SOURCE pin will reset TOPSwitch-GX, which then will come up in the correct state.

PI-2653-033001

Scaling Factors:

TOP242: .45 TOP243 P/G: .75 TOP243 Y/R: .90 TOP244 P/G: 1 TOP244 Y/R: 1.35 TOP245 Y/R: 1.80 TOP246 Y/R: 2.70 TOP247 Y/R: 3.60 TOP248 Y/R: 4.50 TOP249 Y/R: 5.40

IM (µA)

200 180 160 140

120 100 80 60 40

di/dt (mA/µs)

1.1

1.0

0.9

0.8

0.7

0.6

0.5

Current Limit (A)

0.4

0.3

0.2

Minimum

Typical

Maximum and minimum levels are based on characterization.

0 5K 10K 15K 20K 25K 30K 35K 40K

Maximum

Scaling Factors:

TOP242: .45 TOP243 P/G: .75 TOP243 Y/R: .90 TOP244 P/G: 1 TOP244 Y/R: 1.35 TOP245 Y/R: 1.80 TOP246 Y/R: 2.70 TOP247 Y/R: 3.60 TOP248 Y/R: 4.50 TOP249 Y/R: 5.40

External Current Limit Resistor RIL (Ω)

Figure 55. Current Limit vs. External Current Limit Resistance.

PI-2652-033001

45K

August 8, 2000

200 180

160 140 120 100 80 60 40

di/dt (mA/µs)

7/01

Page 42

TOP242-249

Typical Performance Characteristics (cont.)

1.1

1.0

Breakdown Voltage

(Normalized to 25 °C)

0.9

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 56. Breakdown Voltage vs. Temperature.

1.2

1.0

0.8

PI-176B-033001

PI-2555-033001

1.2

1.0

0.8

0.6

0.4

Output Frequency

(Normalized to 25 °C)

0.2

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 57. Frequency vs. Temperature.

1.2

1.0

0.8

PI-1123A-033001

PI-2554-033001

0.6

0.4

Current Limit

(Normalized to 25 °C)

0.2

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 58. Internal Current Limit vs. Temperature.

1.2

1.0

0.8

0.6

0.4

(Normalized to 25 °C)

Overvoltage Threshold

0.2

PI-2553-033001

0.6

0.4

Current Limit

(Normalized to 25 °C)

0.2

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 59. External Current Limit vs. Temperature

with R

1.2

1.0

0.8

0.6

0.4

(Normalized to 25 °C)

0.2

Under-Voltage Threshold

=12 kΩ.

PI-2552-033001

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 60. Overvoltage Threshold vs. Temperature.

E 7/01

August 8, 2000

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Figure 61. Under-Voltage Threshold vs. Temperature.

Page 43

Typical Performance Characteristics (cont.)

1.6

1.0

1.4

1.2

-240 -180 -60-120 0

EXTERNAL CURRENT LIMIT Pin Current (µA)

EXTERNAL CURRENT LIMIT

Pin Voltage (V)

PI-2689-102300

0.4

0.2

0.6

0.8

VX = 1.33 - IXx 0.66 kΩ

-200 µA

≤

-25 µA

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

LINE SENSE Pin Voltage (V)

2.0 0 100 200 300 400

LINE-SENSE Pin Current (µA)

Figure 62a. LINE-SENSE Pin Voltage vs. Current.

PI-2688-102700

PI-2542-102700

TOP242-249

Figure 62b. EXTERNAL CURRENT LIMIT Pin Voltage

vs. Current.

1.6

1.4

1.2

1.0

VM = 1.37 - IMx 1 kΩ

≤

-200 µA

-25 µA

PI-2541-102700

Figure 63a. MULTI-FUNCTION Pin Voltage vs. Current. Figure 63b. MULTI-FUNCTION Pin Voltage vs.

CONTROL Current

Figure 64. Control Current Out at 0% Duty Cycle vs.

See

MULTI-FUNCTION Pin Voltage (V)

-300 -200 -100 0 100 200 300 400 500

Expanded Version

MULTI-FUNCTION Pin Current (µA)

1.2

1.0

0.8

0.6

0.4

(Normalized to 25 °C)

0.2

-50 -25 0 25 50 75 100 125 150

Junction Temperature (°C)

Temperature.

PI-2562-033001

0.8

0.6

0.4

0.2

MULTI-FUNCTION Pin Voltage (V)

-300 -200 -150 -50-250 -100 0

MULTI-FUNCTION Pin Current (µA)

Current (Expanded).

1.2

1.0

0.8

0.6

0.4

(Normalized to 25 °C)

0.2

Onset Threshold Current

-50 -25 0 25 50 75 100 125 150

PI-2563-033001

Junction Temperature (°C)

Figure 65. Max. Duty Cycle Reduction Onset Threshold

Current vs. Temperature.

August 8, 2000

7/01

Page 44

TOP242-249

1.2

1.6

0 20 40 60 80 100

DRAIN Voltage (V)

CONTROL Pin

Charging Current (mA)

IC vs. DRAIN VOLTAGE

PI-2564-101499

0.4

0.8

VC = 5 V

Typical Performance Characteristics (cont.)

DRAIN Current (A)

T T

Scaling Factors:

TOP249 1.00 TOP248 0.83 TOP247 0.67 TOP246 0.50 TOP245 0.33 TOP244 0.25 TOP243 0.17 TOP242 0.08

02468101214161820

DRAIN Voltage (V)

Figure 66. Output Characteristics.

10000

1000

100

Scaling Factors:

TOP249 1.00 TOP248 0.83 TOP247 0.67 TOP246 0.50 TOP245 0.33 TOP244 0.25 TOP243 0.17 TOP242 0.08

CASE CASE

= 25 °C = 100 °C

PI-2645-033001

PI-2646-033001

Figure 67. IC vs. DRAIN Voltage.

600

Scaling Factors:

500

400

300

Power (mW)

200

TOP249 1.00 TOP248 0.83 TOP247 0.67 TOP246 0.50 TOP245 0.33 TOP244 0.25 TOP243 0.17 TOP242 0.08

PI-2650-033001

DRAIN Capacitance (pF)

0 100 200 300 400 500 600

Figure 68. C

vs. DRAIN Voltage.

OSS

7/01

August 8, 2000

Drain Voltage (V)

100

0 200100 400 500300 600

Figure 69. DRAIN Capacitance Power.

1.2

1.0

0.8

0.6

0.4

(Normalized to 25 °C)

0.2

Remote OFF DRAIN Supply Current

-50 0 50 100 150

Junction Temperature (°C)

Figure 70. Remote OFF DRAIN Supply Current

vs. Temperature.

DRAIN Voltage (V)

PI-2690-102700

Page 45

PART ORDERING INFORMATION

TOP242-249

TOPSwitch Product Family GX Series Number Package Identifier

TOP 242 G - TL

.146 (3.71) .156 (3.96)

.860 (21.84) .880 (22.35)

.400 (10.16) .415 (10.54)

.108 (2.74) REF

.467 (11.86) .487 (12.37)

G Plastic Surface Mount DIP

(242, 243 & 244 only)

P Plastic DIP Y Plastic TO-220-7C R Plastic TO-263-7C (available only with TL option)

Package/Lead Options

Blank Standard Configurations

TL Tape & Reel, (G Package: 1 k min., R Package: 750 min.)

TO-220-7C

.165 (4.19) .185 (4.70)

.236 (5.99) .260 (6.60)

7° TYP.

.095 (2.41) .115 (2.92)

.045 (1.14) .055 (1.40)

.570 (14.48) REF.

.670 (17.02) REF.

Y07C

PIN 1

.050 (1.27)

.200 (5.08)

PIN 1

.150 (3.81)

.026 (.66) .032 (.81)

.050 (1.27) BSC

.150 (3.81) BSC

.050 (1.27)

.180 (4.58)

.100 (2.54)

MOUNTING HOLE PATTERN

.010 (.25) M

PIN 7

.150 (3.81)

PIN 1 & 7

.015 (.38) .020 (.51)

.190 (4.83) .210 (5.33)

Notes:

1. Controlling dimensions are inches. Millimeter dimensions are shown in parentheses.

2. Pin numbers start with Pin 1, and continue from left to right when viewed from the front.

3. Dimensions do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15mm) on any side.

4. Minimum metal to metal spacing at the pack age body for omitted pin locations is .068 inch (1.73 mm).

5. Position of terminals to be measured at a location .25 (6.35) below the package body.

6. All terminals are solder plated.

PIN 2 & 4

.040 (1.02) .060 (1.52)

August 8, 2000

PI-2644-040501

7/01

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TOP242-249

-E-

.245 (6.22) .255 (6.48)

Pin 1

-D-

.128 (3.25) .132 (3.35)

-TSEATING PLANE

.100 (2.54) BSC

D S

⊕

.375 (9.53) .385 (9.78)

.014 (.36) .022 (.56)

.004 (.10)

T E D S

⊕

.048 (1.22) .053 (1.35)

.010 (.25) M

.057 (1.45) .063 (1.60)

(NOTE 6)

0.15 (.38)

MINIMUM

.125 (3.18) .135 (3.43)

DIP-8B

Notes:

1. Package dimensions conform to JEDEC specification MS-001-AB (Issue B 7/85) for standard dual-in-line (DIP) package with .300 inch row spacing.

2. Controlling dimensions are inches. Millimeter sizes are shown in parentheses.

3. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side.

4. Pin locations start with Pin 1, and continue counter-clock wise to Pin 8 when viewed from the top. The notch and/or dimple are aids in locating Pin 1. Pin 6 is omitted.

5. Minimum metal to metal spacing at the package body for the omitted lead location is .137 inch (3.48 mm).

6. Lead width measured at package body.

7. Lead spacing measured with the leads constrained to be perpendicular to plane T.

.010 (.25) .015 (.38)

.300 (7.62) BSC

(NOTE 7)

.300 (7.62) .390 (9.91)

PI-2551-101599

P08B

-E-

.245 (6.22) .255 (6.48)

Pin 1

-D-

.128 (3.25) .132 (3.35)

.032 (.81) .037 (.94)

D S

.004 (.10)

⊕

.100 (2.54) (BSC)

.375 (9.53) .385 (9.78)

.048 (1.22) .053 (1.35)

.372 (9.45) .388 (9.86)

E S

⊕

.057 (1.45) .063 (1.60)

(NOTE 5)

.009 (.23)

.010 (.25)

SMD-8B

Heat Sink is 2 oz. Copper

As Big As Possible

Pin 1

Solder Pad Dimensions

.004 (.10) .012 (.30)

.046

.060

.086

.186

.004 (.10)

.036 (0.91) .044 (1.12)

.286

.060

.046

.080

Notes:

1. Controlling dimensions are inches. Millimeter sizes are shown in parentheses.

2. Dimensions shown do not include mold flash or other protrusions. Mold flash or protrusions shall not exceed .006 (.15) on any side.

.420

3. Pin locations start with Pin 1, and continue counter-clock Pin 8 when viewed from the top. Pin 6 is omitted.

4. Minimum metal to metal spacing at the package body for the omitted lead location is .137 inch (3.48 mm).

5. Lead width measured at package body.

6. D and E are referenced datums on the package body.

0 -

PI-2546-040501

G08B

E 7/01

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Page 47

TO-263-7C

TOP242-249

.055 (1.40) .066 (1.68)

.638 (16.21)

.326 (8.28) .336 (8.53)

.208 (5.28)

Ref.

LD #1

.026 (0.66) .032 (0.81)

.380 (9.65)

.396 (10.06) .415 (10.54)

.315 (8.00)

.038 (0.97)

.580 (14.73) .620 (15.75)

.100 (2.54)

Ref.

Solder Pad Dimensions

.128 (3.25)

.050 (1.27)

.245 (6.22)

min.

.045 (1.14) .055 (1.40)

.225 (5.72)

min.

.000 (0.00) .010 (0.25)

.090 (2.29)

-A-

.050 (1.27)

.165 (4.19) .185 (4.70)

Notes:

1. Package Outline Exclusive of Mold Flash & Metal Burr.

2. Package Outline Inclusive of Plating Thickness.

3. Foot Length Measured at Intercept Point Between Datum A Lead Surface.

4. Controlling Dimensions are in Inches. Millimeter Dimensions are shown in Parentheses.

.110 (2.79)

.010 (0.25)

.017 (0.43) .023 (0.58)

8 -

.004 (0.10)

R07C

PI-2664-040501

August 8, 2000

7/01

Page 48

TOP242-249

Revision

Notes

1) Added R package (D2PAK).

2) Corrected abbreviations (s = seconds).

3) Corrected x-axis units in Figure 11 (µA).

4) Added missing external current limit resistor in Figure 25 (RIL).

5) Corrected spelling.

6) Added caption for Table 4.

7) Corrected Breakdown Voltage parameter condition (TJ = 25 °C)

8) Corrected font sizes in figures.

9) Figure 40 replaced.

10) Corrected schematic component values in Figure 44.

Date

11/00

7/01

For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others.

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and

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are registered trademarks of Power Integrations, Inc.

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E 7/01

August 8, 2000