• Simple heat sink mounting using clip provides thermal
impedance equivalent to a TO-220
™
-12 package:
• 66 W universal input output power capability
• Low profile surface mounted for ultra-slim designs
• Heat transfer to PCB via exposed pad and SOURCE pins
• Supports wave or reflow soldering
Figure 1. Typical Flyback Application.
eSIP-7C (E Package)
Figure 2. Package Options.
eSOP-12B (K Package)
eDIP-12B (V Package)
Description
TOPSwitch-JX cost effectively incorporates a 725 V power
MOSFET, high-voltage switched current source, multi-mode
PWM control, oscillator, thermal shutdown circuit, fault
protection and other control circuitry onto a monolithic device.
Typical Applications
• Notebook or laptop adapter
• Generic adapter
• Printer
• LCD monitor
• Set-top box
• PC or LCD TV standby
• Audio amplifier
Output Power Ratings
See next page.
+
-
www.powerint.com August 2012
This Product is Covered by Patents and/or Pending Patent Applications.
Page 2
TOP264-271
Output Power Table
85-265 VAC
Adapter
1
Open
2
Frame
3
Product
5
Adapter
TOP264EG/VG30 W62 W20 W43 W
TOP265EG/VG40 W81 W26 W57 W
TOP266EG/VG60 W119 W40 W86 W
TOP267EG/VG85 W137 W55 W103 W
TOP268EG/VG105 W148 W70 W112 W
TOP269EG/VG128 W162 W80 W120 W
TOP270EG/VG147 W190 W93 W140 W
TOP271EG/VG177 W244 W118 W177 W
PCB Copper Area
4
Open
Frame
3
Product
5
230 VAC ±15%
Adapter
2
TOP264VG21 W34 W12 W22.5 W
TOP264KG30 W49 W16 W30 W
TOP265VG22.5 W36 W15 W25 W
TOP265KG33 W53 W20 W34 W
TOP266VG24 W39 W17 W28.5 W
TOP266KG36 W58 W23 W39 W
TOP267VG27.5 W44 W19 W32 W
TOP267KG40 W65 W26 W45 W
TOP268VG30 W48 W21.5 W36 W
TOP268KG46 W73 W30 W50 W
TOP269VG32 W51 W22.5 W37.5 W
TOP269KG50 W81 W33 W55 W
TOP270VG34 W55 W24.5 W41 W
TOP270KG56 W91 W36 W60 W
TOP271VG36 W59 W26 W43 W
TOP271KG63 W102 W40 W66 W
Table 1. Output Power Table.
Notes:
1. See Key Application Considerations section for more details.
2. Maximum continuous power in a typical non-ventilated enclosed adapter measured at +50 °C ambient temperature.
3. Maximum continuous power in an open frame design at +50 °C ambient temperature.
4. 230 VAC or 110/115 VAC with doubler.
5. Packages: E: eSIP-7C, V: eDIP-12, K: eSOP-12. See Part Ordering Information section.
Metal Heat Sink
230 VAC ±15%
Open
2
Frame
1
4
3
85-265 VAC
Adapter
Open
2
Frame
3
2
Rev. E 08/12
www.powerint.com
Page 3
TOP264-271
CONTROL (C)
EXTERNAL CURRENT
LIMIT (X)
VOLTAGE
MONITOR (V)
FREQUENCY (F)
Z
C
SHUNT REGULATOR/
ERROR AMPLIFIER
I
FB
Figure 3. Functional Block Diagram.
-
+
CURRENT
LIMIT
ADJUST
V
1 V
LINE
SENSE
V
C
+
5.8 V
-
4.8 V
STOP LOGIC
INTERNAL UV
COMPARATOR
STOP
DC
MAX
OSCILLATOR
WITH JITTER
66k/132k
F REDUCTION
F REDUCTION
SOFT START
I
FB
I
PS(UPPER)
I
PS(LOWER)
5.8 V
V
I (LIMIT)
ON/OFF
+ V
BG
T
OV/
OVPV
UV
DC
MAX
K
PS(UPPER)
K
PS(LOWER)
PWM
SOFT
START
SOFT START
D
MAX
CLOCK
OFF
0
1
÷ 16
SHUTDOWN/
AUTO-RESTART
HYSTERETIC
THERMAL
SHUTDOWN
INTERNAL
SUPPLY
SRQ
K
PS(UPPER)
K
PS(LOWER)
CURRENT LIMIT
COMPARATOR
CONTROLLED
TURN-ON
GATE DRIVER
-
+
-
+
-
+
SOURCE (S)
LEADING
EDGE
BLANKING
PI-4511-012810
DRAIN (D)
SOURCE (S)
Pin Functional Description
DRAIN (D) Pin:
High-voltage power MOSFET DRAIN pin. The internal start-up
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.
EXTERNAL CURRENT LIMIT (X) Pin:
Input pin for external current limit adjustment remote-ON/OFF
and device reset. A connection to SOURCE pin disables all
functions on this pin. This pin should not be left floating.
VOLTAGE MONITOR (V) Pin:
Input for OV, UV, line feed-forward with DC
overvoltage protection (OVP), remote-ON/OFF. A connection to
the SOURCE pin disables all functions on this pin. This pin should
not be left floating.
FREQUENCY (F) Pin:
Input pin for selecting switching frequency 132 kHz if connected
to SOURCE pin and 66 kHz if connected to CONTROL pin. This
pin should not be left floating.
reduction, output
MAX
NO CONNECTION (NC) Pin:
Internally not connected, floating potential pin.
E Package
(eSIP-7C)
V
7D5S4F3C2X1
Exposed Pad (On Bottom)
Internally Connected to
SOURCE Pin
Exposed Pad
(Hidden)
Internally
Connected to
SOURCE Pin
S 12
S 11
S 10
S 9
S 8
S 7
V 1
X 2
C 3
F 4
D 6
Exposed Pad Internally
Connected to SOURCE Pin
V Package
(eDIP-12B)
K Package
(eSOP-12B)
1 V
2 X
3 C
4 F
6 D
12 S
11 S
10 S
9 S
8 S
7 S
PI-5568-061011
SOURCE (S) Pin:
Output MOSFET source connection for high-voltage power return.
Primary-side control circuit common and reference point.
www.powerint.com
Figure 4. Pin Conguration (Top View).
3
Rev. E 08/12
Page 4
TOP264-271
V
X
R
IL
12 kΩ
VUV = IUV × R
V
=
OV
For R
4 MΩ
VUV = 102.8 VDC
V
DC
MAX
DC
MAX
C
For RIL = 12 kΩ
I
See Figure 37 for
other resistor values
(R
I
I
×
OV
= 4 MΩ
LS
= 451 VDC
OV
@100 VDC = 76%
@375 VDC = 41%
LIMIT
) to select different
IL
values.
LIMIT
+
R
LS
DC
Input
Voltage
D
CONTROL
S
-
Figure 5. Package Line-Sense and Externally Set Current Limit.
LS + VV
R
LS + VV
= 61%
(IV = IUV)
(IV = IOV)
TOP264-271 Functional Description
Like TOPSwitch-HX, TOP264-271 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 6.
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 and thermal shutdown, the TOP264-271 incorporates many additional functions
that reduce system cost, increase power supply performance
and design flexibility. A patented high-volta ge 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, VOLTAGE-MONITOR, and
EXTERNAL CURRENT LIMIT have been used t o implement
some of the new funct ions. These terminals can be connect ed
to the SOURCE pin to operate the TOP264-271 in a TOPSwitchlike three terminal mode. However, even in this three terminal
mode, the TOP264-271 o ffers many transparent features that do
not require any external components:
1. A fully integrated 17 ms soft-start significantly reduces or
eliminates output overshoot in most applications by sweeping
both current limit and frequency from low to high to limit the
peak currents and voltages during start-up.
2. A maximum duty cycle (DC
storage capacitor, lower input voltage requirement and/or
higher power capability.
3. Multi-mode operation optimizes and improves the power
supply efficiency over the entire load range while maintaining
good cross regulation in multi-output supplies.
4. Switching frequency of 132 kHz reduces the transformer size
with no noticeable impact on EMI.
5. Frequency jittering reduces EMI in the full frequency mode at
high-load condition.
) of 78% allows smaller input
MAX
Auto-Restart
PI-5579-111210
Figure 6. Control Pin Characteristics (Multi-Mode Operation).
7. Packages with omitted pins and lead forming provide large
drain creepage distance.
8. Reduction of the auto-restart duty cycle and frequency to
improve the protection of the power supply and load during
open-loop fault, short-circuit, or loss of regulation.
9. Tighter tolerances on I2f power coefficient, current limit
reduction, PWM gain and thermal shutdown threshold.
The VOLTAGE-MONITOR (V) pin is usually used for line sensing
by connecting a 4 MW resistor from this pin to the rectified DC
high-voltage bus to implement line overvoltage (OV), undervoltage (UV) and dual-slope line feed-forward with DC
MAX
reduction. In this mode, the value of the resistor determines the
OV/UV thresholds and the DC
is reduced linearly with a dual
MAX
slope to improve line ripple rejection. In addition, it also
provides another threshold to implement the latched and
4
Rev. E 08/12
www.powerint.com
Page 5
TOP264-271
hysteretic output overvoltage protection (OVP). The pin can
also be used as a remote-ON/OFF using the IUV threshold.
The EXTERNAL CURRENT LIMIT (X) pin can be 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 input.
The FREQUENCY (F) pin sets the switching frequency in the full
frequency PWM mode 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 the CONTROL pin
instead. Leaving this pin open is not recommended.
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
drain peak current and switching frequency from a low starting
value to the maximum drain peak current at the full frequency
over approximately 17 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 undervoltage 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 an
NMOS current mirror as shown in Figure 3. The output current
of that NMOS current mirror 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 undervoltage comparator keeps VC within a window of
typically 4.8 V 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-sixteen counter, which prevents the output
MOSFET from turning on again until sixteen discharge/charge
cycles have elapsed. This is accomplished by enabling the
output MOSFET only when the divide-by-sixteen counter
reaches the full count (S15). The counter effectively limits
TOP264-271 power dissipation by reducing the auto-restart
duty cycle to typically 2%. Auto-restart 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
triangular waveform for the timing of the pulse width modulator.
This oscillator sets the pulse width modulator/current limit latch
at the beginning of each cycle.
The nominal full switching frequency of 132 kHz was chosen to
minimize transformer size while keeping the fundamental EMI
frequency below 150 kHz. The FREQUENCY pin, when shorted
to the CONTROL pin, lowers the full 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 FRE QUE NCY pin should be
connected to the SOURCE pin for the default 132 kHz.
To further reduce the EMI level, the switching frequency in the
full frequency PWM mode is jittered (frequency modulated) by
approximately ±2.5 kHz for 66 kHz operation or ±5 kHz for
132 kHz operation at a 250 Hz (typical) rate as shown in Figure 7.
The jitter is turned off gradually as the system is entering the
variable frequency mode with a fixed peak drain current.
Pulse Width Modulator
The pulse width modulator implements multi-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 6).
The feedback error signal, in the form of the excess current, 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.
To optimize power supply efficiency, four different control
modes are implemented. At maximum load, the modulator
operates in full frequency PWM mode; as load decreases, the
modulator automatically transitions, first to variable frequency
PWM mode, then to low frequency PWM mode. At light load,
the control operation switches from PWM control to multi-cyclemodulation control, and the modulator operates in multi-cyclemodulation mode. Although different modes operate differently
to make transitions between modes smooth, the simple
relationship between duty cycle and excess CONTROL pin
current shown in Figure 6 is maintained through all three PWM
www.powerint.com
5
Rev. E 08/12
Page 6
PI-4530-041107
Switching
Frequency
TOP264-271
f
+
OSC
f
-
OSC
4 ms
Maximum Duty Cycle
The maximum duty cycle, DC
, is set at a default maximum
MAX
value of 78% (typical). However, by connecting the VOLTAGEMONITOR t o t he r ectified DC hi gh-voltage bus through a resistor
with appropriate value (4 MW typical), the maximum duty cycle
can be made to decrease from 78% to 40% (typical) when input
line voltage increases from 88 V to 380 V, with dual gain slopes.
V
DRAIN
Time
Figure 7. Switching Frequency Jitter (Idealized V
Waveforms).
DRAIN
modes. Please see the following sections for the details of the
operation of each mode and the transitions between modes.
Full Frequency PWM mode: The PWM modulator enters full
frequency PWM mode when the CONTROL pin current (IC)
reaches IB. In this mode, the average switching frequency is
kept constant at f
cycle is reduced from DC
(pin selectable 132 kHz or 66 kHz). Duty
OSC
through the reduct ion o f t he on -time
MAX
when IC is increased beyond IB. This operation is identical to the
PWM control of all other TOPSwitch families. TOP264-271 only
operates in this mode if the cycle-by-cycle peak drain current
stays above k
and I
(set) is the current limit externally set via the EXTERNAL
LIMIT
PS(UPPER)
× I
LIMIT
(set), where k
is 55% (typical)
PS(UPPER)
CURRENT LIMIT (X) pin.
Variable Frequency PWM mode: When peak drain current is
lowered to k
PS(UPPER)
× I
(set) as a result of power supply load
LIMIT
reduction, the PWM modulator initiates the transition to variable
frequency PWM mode, and gradually turns off frequency jitter.
In this mode, peak drain current is held constant at k
I
(set) while switching frequency drops from the initial full
LIMIT
frequency of f
frequency of f
(132 kHz or 66 kHz) towards the minimum
OSC
(30 kHz typical). Duty cycle reduction is
MCM(MIN)
PS(UPPER)
×
accomplished by extending the off-time.
Low Frequency PWM mode: When switching frequency
reaches f
(30 kHz typical), the PWM modulator starts to
MCM(MIN)
transition to low frequency mode. In this mode, switching
frequency is held constant at f
and duty cycle is reduced,
MCM(MIN)
similar to the full frequency PWM mode, through the reduction
of the on-time. Peak drain current decreases from the initial
value of k
k
PS(LOWER)
× I
PS(UPPER)
(set), where k
LIMIT
× I
(set) towards the minimum value of
LIMIT
is 25% (typical) and I
PS(LOWER)
LIMIT
(set)
is the current limit externally set via the X pin.
Multi-Cycle-Modulation mode: When peak drain current is
lowered to k
PS(LOWER)
× I
(set), the modulator transitions to
LIMIT
multi-cycle-modulation mode. In this mode, at each turn-on,
the modulator enables output switching for a period of T
at the switching frequency of f
at 30 kHz) with the peak drain current of k
(4 or 5 consecutive pulses
MCM(MIN)
PS(LOWER)
and stays off until the CONTROL pin current falls below I
This mode of operation not only keeps peak drain current low
× I
(set),
LIMIT
MCM(MIN)
C(OFF)
.
but also minimizes harmonic frequencies between 6 kHz and
30 kHz. By avoiding transformer resonant frequency this way,
all potential transformer audible noises are greatly suppressed.
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 CONTROL pin dynamic
impedance ZC sets the gain of the error amplifier. The CONTROL
pin clamps external circuit signals to the VC voltage level. The
CONTROL pin current in excess of the supply current is
separated by the shunt regulator and becomes the feedback
current IFB for the pulse width modulator.
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
with a threshold voltage. High drain
DS(ON)
to exceed the threshold voltage and turns
DS(ON)
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 TOP264-271 is preset internally.
However, with a resistor connected between EXTERNAL
CURRENT LIMIT (X) pin and SOURCE pin, current limit can be
programmed externally to a lower level between 30% and 100%
of the default current limit. By setting current limit low, a larger
TOP264-271 than necessary for the power required can be used
to take advantage of the lower R
for higher efficiency/
DS(ON)
smaller heat sinking requirements. With a second resistor
connected between the EXTERNAL CURRENT LIMIT (X) pin
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. This is due to dynamic
characteristics of the MOSFET. During start-up and fault
conditions the controller prevents excessive drain currents by
reducing the switching frequency.
Line Undervoltage Detection (UV)
At power-up, UV keeps TOP264-271 off until the input line
voltage reaches the undervoltage threshold. At power-down,
6
Rev. E 08/12
www.powerint.com
Page 7
TOP264-271
~
~
V
UV
V
LINE
0 V
~
~
~
~
~
~
~
~
S14
S15
V
C
0 V
V
DRAIN
0 V
V
OUT
0 V
1
Note: S0 through S15 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.
2
UV prevents auto-restart attempts after the output goes out of
regulation. This eliminates power-down glitches caused by
slow discharge of the large input storage capacitor present in
applications such as standby supplies. A single resistor
connected from the VOLTAGE-MONITOR pin 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 44% 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
S13 S12S0S15S13 S12S0S15S14
~
~
~
~
~
~
3
~
~
~
~
~
~
In order to reduce the no-load input power of TOP264-271
designs, the V pin operates at very low currents. This requires
careful layout considerations when designing the PCB to avoid
noise coupling. Traces and components connected to the V pin
should not be adjacent to any traces carrying switching currents.
These include the drain, clamp network, bias winding return or
power traces from other converters. If the line sensing features
are used, then the sense resistors must be placed within 10 mm
of the V pin to minimize the V pin node area. The DC bus
should then be routed to the line-sense resistors. Note that
external capacitance must not be connected to the V pin as this
may cause misoperation of the V pin related functions.
loses regulation before reaching the UV low threshold, the
device will enter auto-restart. At the end of each auto-restart
cycle (S15), 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 the OV feature.
Hysteretic or Latching Output Overvoltage Protection (OVP)
The detection of the hysteretic or latching output overvoltage
protection (OVP) is through the trigger of the line overvoltage
threshold. The V pin voltage will drop by 0.5 V, and the
controller measures the e xternal a ttached impedance immediat ely
after this voltage drops. If IV exceeds I
Line Overvoltage Shutdown (OV)
The same resistor used for UV also sets an overvoltage
threshold, which, once exceeded, will force TOP264-271 to
stop switching instantaneously (after completion of the current
switching cycle). If this condition lasts for at least 100 ms, the
TOP264-271 output will be forced into off state. When the line
voltage is back to normal with a small amount of hysteresis
provided on the OV threshold to prevent noise triggering, the
state machine sets to S13 and forces TOP264-271 to go
through the entire auto-restart sequence before attempting to
switch again. The ratio of OV and UV thresholds is preset at
4.5, as can be seen in Figure 9. When the MOSFET is off, the
rectified DC high-voltage surge capability is increased to the
voltage rating of the MOSFET (725 V), due to the absence of the
reflected voltage and leakage spikes on the drain. The OV
feature can be disabled independent of the UV feature.
longer than 100 ms, TOP264-271 will latch into a permanent
off-state for the latching OVP. It only can be reset if IX exceeds
I
= -27 mA (typ) or VC goes below the power-up reset
X(TH)
threshold (V
exceed I
OV(LS)
will initiate the line overvoltage and the hysteretic OVP. Their
behavior will be identical to the line overvoltage shutdown (OV)
that has been described in detail in the previous section.
During a fault condition resulting from loss of feedback, output
voltage will rapidly rise above the nominal voltage. The increase
in output voltage will also result in an increase in the voltage at
the output of the bias winding. A voltage at the output of the
bias winding that exceeds of the sum of the voltage rating of the
Zener diode connected from the bias winding output to the V
pin and V pin voltage, will cause a current in excess of IV to be
injected into the V pin, which will trigger the OVP feature.
S14
2
) and then back to normal. If IV does not
C(RESET)
S13
S12
~
~
~
~
~
~
4
S0 S15
S15
(336 mA typical)
OV(LS)
5.8 V
4.8 V
PI-4531-121206
or exceeds no longer than 100 ms, TOP264-271
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TOP264-271
If the power supply is operating under heavy load or low input
line conditions when an open-loop occurs, the output voltage
may not rise significantly. Under these conditions, a latching
shutdown will not occur until load or line conditions change.
Nevertheless, the operation provides the desired protection by
preventing significant rise in the output voltage when the line or
load conditions do change. Primary-side OVP protection with
the TOP264-271 in a typical application will prevent a nominal
12 V output from rising above approximately 20 V under openloop conditions. If greater accuracy is required, a secondary
sensed OVP circuit is recommended.
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. 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) at a voltage slightly
MAX
lower than the UV threshold to 36% (typical) at the OV threshold.
DC
of 36% at high-line was chosen to ensure that the power
MAX
capability of the TOP264-271 is not restricted by this feature under
normal operation. TOP264-271 provides a better fit to the ideal
feed-forward by using two reduction slopes: -1% per mA for all bus
voltage less than 195 V (typical for 4 MW line impedance) and
-0.25% per mA for all bus voltage more than 195 V.
Remote-ON/OFF
TOP264-271 can be turned on or off by controlling the current into
the VOLTA GE- MONIT OR pin or out from the EXTERNAL CURRENT
LIMIT pin. In addition, the VOLTAGE-MONITOR pin has a 1 V
threshold comparator connect ed at it s input. This voltage
threshold can also be used to perform remote-ON/OFF control.
When a signal is received at the VOLTAGE-MONITOR pin or the
EXTERNAL CURRENT LIMIT pin to disable the output through
any of the pin functions such as OV, UV and remote-ON/OFF,
TOP264-271 alwa ys comple tes its current switching cycle before
the output is forced off.
As seen above, the remote-ON/OFF feature can also be used
as a standby or power switch to turn off the TOP264-271 and
keep it in a very low power consumption state for indefinitely long
periods. If the TOP264-271 is held in remote-off state for long
enough time to allow the CONTROL pin to discharge to the
internal supply undervoltage threshold of 4.8 V (approximately
32 ms for a 47 mF CONTROL pin capacitance), the CONTROL
pin goes into the hysteretic mode of regulation. In this mode,
the CONTROL pin goes through alt ernate 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 (<100 mW typical at
230 VAC with X pin open). When the TOP264-271 is remotely
Voltage Monitor and External Current Limit Pin Table*
Figure Number131415161718192021222324
Three Terminal Operation
Line Undervoltage (UV)
Line Overvoltage (OV)
Line Feed-Forward (DC
Output Overvoltage Protection (OVP)
Overload Power Limiting (OPP)
External Current Limit
Remote-ON/OFF
Device Reset
Fast AC Reset
AC Brown-Out
*This table is only a partial list of many VOLTAGE MONITOR and EXTERNAL CURRENT LIMIT Pin Configurations that are possible.
Table 2. VOLTAGE MONITOR (V) Pin and EXTERNAL CURRENT LIMIT (X) Pin Conguration Options.
MAX
)
3
33333
33333
3333
3
3
333333
333
333
3
3
8
Rev. E 08/12
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Page 9
TOP264-271
V PinX Pin
Output
MOSFET
Switching
Current
Limit
Maximum
Duty Cycle
(Enabled)
(Disabled)
I
(Default)
LIMIT
DC
(78%)
MAX
I
REM(N)
I
UV
Disabled when supply
output goes out of
regulation
I
OV
(Non-Latching) (Latching)
I
OV(LS)
I
I
I
V
BG
Pin Voltage
-250-200-150-100-500255075100125336
X and V Pins 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. For a detailed description of
each functional pin operation refer to the Functional Description section of the data sheet.
Figure 9. VOLTAGE MONITOR and EXTERNAL CURRENT LIMIT Pin Characteristics.
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 mF 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 turn-off sequences that may be required
in certain applications such as inkjet and laser printers.
Soft-Start
The 17 ms soft-start sweeps the peak drain current and switching
frequency linearly from minimum to maximum value by operating
through the low frequency PWM mode and the variable
frequency mode before entering the full frequency mode. 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 (VC), due to
remote-off or thermal shutdown conditions. This effectively
minimizes current and voltage stresses on the output MOSFET,
I
PI-5528-060409
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9
Rev. E 08/12
Page 10
TOP264-271
the clamp circuit and the output rectifier during start-up. This
feature also helps minimize output overshoot and prevents
saturation of the transformer during start-up.
Shutdown/Auto-Restart (for OCP, SCP, OPP)
To minimize TOP264-271 power dissipation under fault
conditions such as over current (OC), short-circuit (SC) or over
power (OP), the shutdown/auto-restart circuit turns the power
supply on and off at an auto-restart duty cycle of typically 2% if
an out of regulation condition persists. Loss of regulation
interrupts the external current into the CONTROL pin. VC
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.
Hysteretic Over-Temperature Protection (OTP)
Temperature protection is provided by a precision analog circuit
that turns the output MOSFET off when the junction temperature
exceeds the thermal shutdown temperature (142 °C typical).
When the junction temperature cools to below the lower
hysteretic temperature point, normal operation resumes, thus
providing automatic recovery. A large hysteresis of 75 °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) triangular waveform is
present on the CONTROL pin while in thermal shutdown.
Bandgap Reference
All critical TOP264-271 internal voltages are derived from a
temperature-compensated bandgap reference. This voltage
reference i s used to g ener ate all other internal current referen ces,
which are trimmed to accurately set the switching frequency,
MOSFET gate drive current, current limit, and the line OV/UV/
OVP thresholds. TOP264-271 has improved circuitry to
maintain all of the above critical parameters within very tight
absolute and temperature tolerances.
High-Voltage Bias Current Source
This high-voltage current source biases TOP264-271 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 (IC) and discharge currents (I
CD1
and I
CD2
).
This current source 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.
10
Rev. E 08/12
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Page 11
CONTROL (C)
EXTERNAL CURRENT LIMIT (X)
200 µA
VBG + V
TOP264-271
(Negative Current Sense - ON/OFF,
Current Limit Adjustment, OVP Latch Reset)
T
VOLTAGE MONITOR (V)
V
REF
400 µA
Figure 10. VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pin Input Simplied Schematic.
(Voltage Sense, ON/OFF)
1 V
(Positive Current Sense - Undervoltage,
Overvoltage, ON/OFF, Maximum Duty
Cycle Reduction, Output Over-
voltage Protection)
PI-5567-030910
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11
Rev. E 08/12
Page 12
TOP264-271
Typical Uses of FREQUENCY (F) Pin
+
DC
Input
Voltage
D
S
CONTROL
C
F
-
PI-2654-071700
Figure 11. Full Frequency Operation (132 kHz).Figure 12. Half Frequency Operation (66 kHz).
+
DC
Input
Voltage
-
D
CONTROL
S
C
F
PI-2655-071700
12
Rev. E 08/12
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Page 13
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins
PI-6119-061011
V Package (eDIP-12)
+
DC
Input
Voltage
-
D
S
E Package
(eSIP-7C)
V
CONTROL
XF
V X C SF D
C
C
S D
S 12
S 11
S 10
S 9
S 8
S 7
S
K Package (eSOP-12)
1 V
2 X
3 C
4 F
6 D
DC
D C
S
Figure 13. Three Terminal Operation (VOLTAGE MONITOR and EXTERNAL
CURRENT LIMIT Features Disabled. FREQUENCY Pin Tied to
SOURCE or CONTROL Pin.)
1 V
2 X
3 C
4 F
6 D
S 12
S 11
S 10
S 9
S 8
S 7
Figure 14. Line-Sensing for Undervoltage, Overvoltage and Line Feed-Forward.
+
DC
Input
Voltage
-
LS
D
CONTROL
S
TOP264-271
VUV = IUV × R
V
I
=
×
OV
OV
= 4 MΩ
For R
LS
= 102.8 VDC
V
4 MΩR
V
UV
V
=
OV
@100 VDC = 76%
DC
MAX
@375 VDC = 41%
DC
MAX
C
451 VDC
LS + VV
R
LS + VV
PI-4717-120307
(IV = IUV)
(IV = IOV)
+
DC
Input
Voltage
VUV = IUV × R
V
I
=
×
OV
OV
For R
= 4 MΩ
LS
= 102.8 VDC
V
UV
V
R
4 MΩ
LS
VR
OVP
DC
DC
451 VDC
=
OV
Sense Output Voltage
R
OVP
MAX
MAX
(IV = IUV)
LS + VV
(IV = IOV)
R
LS + VV
@ 100 VDC = 76%
@ 375 VDC = 41%
DV
CONTROL
-
S
C
R
>3kΩ
OVP
PI-4719-120307
Figure 15. Line-Sensing for Undervoltage, Overvoltage, Line Feed-Forward and
Hysteretic Output Overvoltage Protection.
+
4 MΩ
V
R
LS + VV
(IV = IOV)
= I
×
OV
OV
For Values Shown
V
= 457.2 VDC
OV
55 kΩ
1N4148
C
DC
Input
Voltage
R
LS
D
V
CONTROL
-
S
PI-4721-120307
Figure 17. Line-Sensing for Overvoltage Only (Undervoltage Disabled). Maximum
Duty Cycle Reduced at Low-Line and Further Reduction with
Increasing Line Voltage.
+
DC
Input
V
= RLS × I
UV
4 MΩ
For Values Shown
V
UV
R
LS
40 kΩ
UV + VV
= 103.8 VDC
Voltage
DV
6.2 V
CONTROL
-
S
C
PI-4720-120307
Figure 16. Line-Sensing for Undervoltage Only (Overvoltage Disabled).
+
DC
Input
Voltage
D
S
CONTROL
X
R
IL
For R
= 12 kΩ
IL
= 61%
I
LIMIT
For R
= 19 kΩ
IL
= 37%
I
LIMIT
See Figure 37 for other
resistor values (R
C
-
PI-5580-111210
Figure 18. External Set Current Limit.
(IV = IUV)
).
IL
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13
Rev. E 08/12
Page 14
TOP264-271
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins (cont.)
+
DC
Input
Voltage
-
2.5 MΩR
LS
D
CONTROL
S
X
R
6 kΩ
I
=
100% @ 100 VDC
LIMIT
53% @ 300 VDC
=
I
LIMIT
C
IL
PI-5465-061009
Figure 19. Current Limit Reduction with Line Voltage.
+
DC
Input
Voltage
-
D
S
CONTROL
X
can be an optocoupler
Q
R
output or can be replaced
by a manual switch.
For R
I
For R
C
R
IL
Q
I
R
16 kΩ
=
IL
= 61%
LIMIT
=
IL
= 37%
LIMIT
ON/OFF
PI-5531-072309
Figure 21. Active-On Remote-ON/OFF with Externally Set Current Limit,
and Latch Reset
12 kΩ
19 kΩ
+
DC
Input
Voltage
-
D
S
QR can be an optocoupler
output or can be replaced by
a manual switch.
CONTROL
Q
R
C
X
47 KΩ
ON/OFF
PI-5466-061009
Figure 20. Active-On (Fail Safe) Remote-ON/OFF, and Latch Reset.
V
X
VUV = IUV × R
V
I
=
OV
OV
@100 VDC = 76%
DC
4 MΩ
MAX
@375 VDC = 41%
DC
MAX
can be an optocoupler
Q
R
output or can be replaced
by a manual switch.
C
R
IL
Q
R
16 kΩ
R
×
For R
I
LS + VV
LS + VV
LIMIT
IL
ON/OFF
PI-5467-061009
+
DC
Input
Voltage
-
D
S
R
LS
CONTROL
Figure 22. Active-On Remote-ON/OFF with Line-Sense and External
Current Limit, and Latch Reset.
(IV = IUV)
(IV = IoV)
=
12 kΩ
= 61%
+
DC
Input
Voltage
-
D
S
R
LS
V
CONTROL
X
12 kΩ
4 MΩ
R
IL
VUV = IUV x R
V
I
=
x
OV
OV
For R
= 4 MΩ
LS
= 102.8 VDC
V
UV
= 451 VDC
V
OV
DC
@ 100 VDC = 76%
MAX
@ 375 VDC = 41%
DC
MAX
C
For R
IL
I
LIMIT
See Figure 37 for
other resistor values
) to select different
(R
IL
values.
I
LIMIT
LS + VV
R
LS + VV
= 12 kΩ
= 61%
(IV = IUV)
(IV = IoV)
PI-5565-111210
+
DC
Input
Voltage
-
Typ. 65 VAC brownout threshold.
<3 s AC latch reset time.
Higher gain QR allows increasing R1/
decreasing C1 for lower no-load input
power.
D
CONTROL
S
C
X
R
IL
Q
R
39 kΩ
R1
4 MΩ
R2
PI-5652-110609
1N4007
C1
47 nF
Figure 23. Line Sensing and Externally Set Current Limit.Figure 24. Externally Set Current Limit, Fast AC Latch Reset and Brown-Out.
14
Rev. E 08/12
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AC
Input
Page 15
PI-5667-030810
Application Example
TOP264-271
Low No-Load, High Efciency, 65 W, Universal Input
Adapter Power Supply
The circuit shown in Figure 25 shows a 90 VAC to 265 VAC
input, 19 V, 3.42 A output power supply, designed for operation
inside a sealed adapter case type. The goals of the design were
highest full load efficiency, highest a v era ge e fficiency (average of
25%, 50%, 75% and 100% load points), and very low no-load
consumption. Additional requirements included latching output
overvoltage shutdown and compliance to safety agency limited
power source (LPS) limits. Measured efficiency and no-load
performance is summarized in the table shown in the schematic
which easily exceed current energy efficiency requirements.
In order to meet these design goals the following key design
decisions were made.
PI Part Selection
• One device size larger selected than required for power
delivery to increase efficiency
The current limit programming feature of TOPSwitch-JX allows
the selection of a larger device than needed for power delivery.
This gives higher full load, low-line efficiency by reducing the
MOSFET conduction losses (I
RMS
2
× R
) but maintains the
DS(ON)
overload power, transformer and other components size as if a
smaller device had been used.
For this design one device size larger than required for power
delivery (as recommended by the power table) was selected.
This typically gives the highest efficiency. Further increases in
device size often results in the same or lower efficiency due to
the larger switching losses associated with a larger MOSFET.
Line-Sense Resistor Values
• Increasing line-sensing resistance from 4 MW to 10.2 MW to
reduce no-load input power dissipation by 16 mW
Line-sensing is provided by resistors R3 and R4 and sets the
line undervoltage and overvoltage thresholds. The combined
value of these resistors was increased from the standard 4 MW
to 10 .2 MW. This reduced the resistor dissipation, and therefore
contribution to no-load input power, from ~26 mW t o ~10 mW. To
compensate the resultant change in the UV (turn-on) threshold
resistor R2 0 w as a dded be tween t he CONTR OL and V OLTAGEMONITOR pins. This adds a DC current equal to ~16 mA into the
VOLTAGE MONITOR pin, requiring only 9 mA to be provided via
R3 and R4 to reach the VOLTAGE MONITOR pin UV (turn-on)
threshold current of 25 mA and setting the UV threshold to 95 VDC.
This technique does effectively disable the line OV feature as
the resultant OV threshold is raised from ~450 VDC to ~980 VDC.
However in this design there was no impact as the value of
input capacitance (C2) was sufficient to allow the design to
withstand differential line surges greater than 2 kV without the
peak drain voltage reaching the BV
rating of U1.
DSS
Specific guidelines and detailed calculations for the value of
R20 may be found in the TOPSwitch-JX Application Note (AN-47).
Clamp Configuration – RZCD vs RCD
• An RZCD (Zener bleed) was selected over an RCD clamp to
give higher light load efficiency and lower no-load consumption
The clamp network is formed by VR2, C4, R5, R6, R11, R28,
R29 and D2. It limits the peak drain voltage spike caused by
leakage inductance to below the BV
rating of the internal
DSS
L
N
Input Voltage (VAC)
Full Power Efciency (%) 86.689.1
Average Efciency (%)89.5
No-load Input Power (mW) 57.7
D1
GBU8J
600 V
L3
12 mH
R1
2.2 MΩR22.2 MΩ
C1
330 nF
275 VAC
L4
200 µH
F1
4 A
90 - 265
VAC
C2
120 µF
400 V
90230
115
88.4
89.8
59.7 86.7
R3
5.1 MΩR710 MΩ
R4
5.1 MΩ
R9
11 kΩ
1%
R8
10 MΩ
R11
300 Ω
2.2 nF
R24
2.2 Ω
C5
1 kV
VR2
SMAJ250A
R5
300 Ω
R29
300 Ω
TOPSwitch-JX
U1
TOP269EG
D
S
C4
1000 pF
630 V
R6
150 Ω
D2
RS1K
CONTROL
R28
300 Ω
D3
BAV19WS
R20
191 kΩ
V
FX
MMBT4403
1%
C
3
1
Q1
C9
220 nF
25 V
1 nF
250 VAC
RM10
C6
100 nF
50 V
C11
T1
FL1
FL2
5
BAV21WS-
7-F
4
R14
20 Ω
4.7 kΩ
ZMM5244B-7
Figure 25. Schematic of High Efciency 19 V, 65 W, Universal Input Flyback Supply with Low No-load.
www.powerint.com
D4
R12
VR1
1/8 W
6.8 Ω
1/8 W
470 pF
R25
20 Ω
R13
C7
47 µF
16 V
C15
50 V
C12
1 nF
100 V
V30100C
R10
100 Ω
PS2501-
MMBT3904
D5
C10
56 µF
35 V
U3B
1-H-A
R15
33 Ω
Q2
C13
470 µF
25 V
PS2501-
C22
100 nF
50 V
470 µF
U3A
1-H-A
C14
25 V
R16
20 kΩ
1.6 kΩ
6.8 nF
147 kΩ
R27
10 kΩ
C16
22 nF
50 V
U2
LMV431AIMF
1%
R22
C19
50 V
R17
1%
R19
20 kΩ
R18
10 kΩ
1%
C21
10 nF
50 V
19 V, 3.42 A
RTN
15
Rev. E 08/12
Page 16
TOP264-271
TOPSwitch-JX MOSFET. This arrangement was selected over
a standard RCD clamp to improve light load efficiency and no-load
input power.
In a standard RCD clamp C4 would be discharged by a parallel
resistor rather than a resistor and series Zener. In an RCD clamp
the resistor value is selected to limit the peak drain voltage
under full load and overload conditions. However under light or
no-load conditions this resistor value now causes the capacitor
voltage to di scharge si gnificant ly as both the leakage inductance
energy and switching frequency are lower. As the capacitor has
to be recharged to above the reflected output voltage each
switching cycle the lower capacitor voltage represents wasted
energy. It has the effect of making the clamp dissipation
appear as a significant load just as if it were connected to the
output of the power supply.
The RZCD arrangement solves this problem by preventing the
voltage across the capacitor discharging below a minimum
value (defined by the voltage rating of VR2) and therefore
minimizing clamp dissipation under light and no-loa d condit ions .
Resistors R6 and R28 provide damping of high frequency
ringing to reduce EMI. Due to the resistance in series with VR2,
limiting the peak current, standard power Zeners vs a TVS type
may be used for lower cost (although a TVS type was selected
due to availability of a SMD version). Diode D2 was selected to
have an 800 V vs the typical 600 V rating due to its longer
reverse recovery time of 500 ns. This allows some recovery of
the clamp energy during the reverse recovery time of the diode
improving efficiency. Multiple resistors were used in parallel to
share dissipation as SMD components were used.
Feedback Configuration
• A Darlington connection formed together with optocoupler
transistor to reduce secondary-side feedback current and
therefore no-load input power.
• Low voltage, low current voltage reference IC used on
secondary-side to reduce secondary-side feedback current
and therefore no-load input power.
• Bias winding voltage tuned to ~9 V at no-load, high-line to
reduce no-load input power.
Typically the feedback current into the CONTROL pin at
high-line is ~3 mA. This current is both sourced from the bias
winding (voltage across C10) and directly from the output. Both
of these represent a load on the output of the power supply.
To minimize the dissipation from the bias winding under no-load
conditions the number of bias winding turns and value of C10
was adjusted to give a minimum voltage across C10 of ~9 V.
This is the minimum required to keep the optocoupler biased.
To minimize the dissipation of the secondary-side feedback
circuit Q2 was added to form a Darlington connection with U3B.
This reduced the feedback current on the secondary to ~1 mA.
The increased loop gain (due to the hFE of the transistor) was
compensated by increasing the value of R16 and the addition of
R25. A standard 2.5 V TL431 voltage reference was replaced
with the 1.24 V LMV431 to reduce the supply current requirement
from 1 mA to 100 mA.
Output Rectifier Choice
• Higher current rating, low V
Schottky rectifier diode selected
F
for output rectifier.
A dual 15 A, 100 V Schottky rectifier diode with a VF of 0.455 V
at 5 A was selected for D5. This is a higher current rating than
required to reduce resistive and forward voltage losses to improve
both full load and average efficiency. The use of a 100 V Schottky
was possible due to the high transformer primary to secondary
turns ratio (V
= 110 V) which was in turn possible due to the
OR
high-voltage rating of the TOPSwitch-JX internal MOSFET.
Increased Output Overvoltage Shutdown Sensitivity
• Transistor Q1 and VR1 added to improve the output over-
voltage shutdown sensitivity.
During an open-loop condition the output and therefore bias
winding voltage will rise. When this exceeds the voltage of VR1
plus a VBE voltage drop Q1 turns on and current is fed into the
VOLTAGE MONITOR pin. The addition of Q1 ensures that the
current into the VOLTAGE MONITOR pin is sufficient to exceed
the latching shutdown threshold even when the output is fully
loaded while the supply is operating at low-line as under this
condition the output voltage overshoot is relatively small
Output overload power limitation is provided via the current limit
programming feature of the X pin and R7, R8 and R9. Resistors
R8 and R9 reduce the device current limit as a function of
increasing line voltage to provide a roughly flat overload power
characteristic, below the 100 VA limited power source (LPS)
requirement. In order to still meet this under a single fault
condition (such as open circuit of R8) the rise in the bias voltage
that occurs during an overload condition is also used to trigger
a latching shutdown.
16
Rev. E 08/12
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Page 17
TOP264-271
Very Low No-Load, High Efciency, 30 W, Universal
Input, Open Frame, Power Supply
The circuit shown in Figure 26 below shows an 85 VAC to
265 VAC input, 12 V, 2.5 A output power supply. The goals of
the design were highest full load efficiency, average efficiency
(average of 25%, 50%, 75% and 100% load points), very low noload consumption. A dditional r equir ements included la tching
output overvoltage shutdown and compliance to safety agency
limited power source (LPS) limits. Actual efficiency and no-load
performance is summarized in the table shown in the schematic
which easily exceed current energy efficiency requirements.
In order to meet these design goals the following key design
decisions were made.
PI Part Selection
• Ambient of 40 °C allowed one device size smaller than
indicated by the power table
The device selected for this design was based on the 85-265 VAC,
Open Frame, PCB heat sinking column of power table (Table 1).
One device size smaller was selected (TOP266V vs TOP267V)
due to the ambient specification of 40 °C (vs the 50°C assumed
in the power table) and the optimum PCB area and layout for
the device heat sink. The subsequent thermal and efficiency
data confirmed this choice. The maximum device temperature
was 107 °C at full load, 40 °C, 85 VAC, 47 Hz (worst-case
conditions) and average efficiency exceeded 83% ENERGY
STAR and EuP Tier 2 requirements.
Transformer Core Selection
• 132 kHz switching frequency allowed the selection of smaller
core for lower cost.
The size of the magnetic core is a function of the switching
frequency. The choice of the higher switching frequency of
132 kHz allowed for the use of a smaller core size. The higher
switching frequency does not negatively impact the efficiency in
TOPSwitch-JX designs due its small drain to source capacitance
(C
) as compared to that of discrete MOSFETs.
OSS
Line-Sense Resistor Values
• Increasing line-sensing resistance from 4 MW to 10.2 MW to
reduce no-load input power dissipation by 16 mW.
Line-sensing is provided by resistors R1 and R2 and sets the
line undervoltage and overvoltage thresholds. The combined
value of these resistors was increased from the standard 4 MW
to 10 .2 MW. This reduces the current into the VOLTAGE
MONITOR pin, and therefore contribution to no-load input po wer,
from ~ 26 mW to ~10 mW. To compensate the resultant change in
the UV threshold resistor R12 was added between the CONTROL
and VOLTAGE-MONITOR pins. This adds a DC current equal to
~16 mA into the VOLTAGE MONITOR pin, requiring only 9 mA to
be provided via R1 and R2 to reach the VOLTAGE MONITOR
pin UV threshold current of 25 mA and setting the UV threshold
to approximately 95 VDC.
This technique does effectively disable the line OV feature as
the resultant OV threshold is raised from ~450 VDC to ~980 VDC.
However in this design there was no impact as the value of
input capacitance (C3) was sufficient to allow the design to
withstand differential line surges greater than 1 kV without the
peak drain voltage reaching the BV
rating of U1.
DSS
Specific guidelines and detailed calculations for the value of R12
may be found in the TOPSwitch-JX Application Note.
Input Voltage (VAC)
Full Load Efciency (%) 81.2586.21
Average Efciency (%)85.13
No-load Input Power (mW) 60.8
L1
14 mH
C1
100 nF
275 VAC
F1
3.15 A
L
85 - 264
VAC
N
85230
115
83.94
84.97
61.98 74.74
D1
1N4007D21N4007
C3
82 µF
400 V
D3
1N4007D41N4007
R1
5.1 MΩR310 MΩ
R2
5.1 MΩ
10 MΩ
TOPSwitch-JX
R15
14.3 kΩ
1%
R4
U1
TOP266VG
P6KE180A
R5
10 kΩ
1/2 W
VR1
D
S
D5
FR107
CONTROL
C4
4.7 nF
1 kV
BAV19WS
191 kΩ
V
FX
D6
R12
C11
1 nF
250 VAC
6
4
NC
NC
T1
EF25
VR3
ZMM5245B-7
1%
C
C9
100 nF
50 V
7,8
11,12
1
2
D7
BAV21WS-
7-F
R16
6.8 Ω
1/8 W
C10
47 µF
25 V
C12
1 nF
200 V
R9
10 Ω
LTV817D
Figure 26. Schematic of High Efciency 12 V, 30 W, Universal Input Flyback Supply with Very Low No-load.
C7
47 µF
25 V
U2B
D8,9
SB560
R17
22 Ω
C14
680 µF
25 V
R18
110 Ω
C18
47 nF
50 V
C15
680 µF
25 V
3.3 µH
R19
470 Ω
D10
LL4148
U2A
LTV817D
U3
LMV431A
1%
L2
C20
33 nF
50 V
C16
100 µF
25 V
R21
86.6 kΩ
1%
R23
10 kΩ
1%
PI-5775-030810
12 V, 2.5 A
RTN
www.powerint.com
17
Rev. E 08/12
Page 18
TOP264-271
Clamp Configuration – RZCD vs RCD
• An RZCD (Zener bleed) was selected over RCD to give higher
light load efficiency and lower no-load consumption.
The clamp network is formed by VR1, C4, R5 and D5. It limits
the peak drain voltage spike caused by leakage inductance to
below the BV
rating of the internal TOPSwitch-JX MOSFET.
DSS
This arrangement was selected over a standard RCD clamp to
improve light load efficiency and no-load input power.
In a standard RCD clamp C4 would be discharged by a parallel
resistor rather than a resistor and series Zener. In an RCD
clamp the resistor value of R5 is selected to limit the peak drain
voltage under full load and overload conditions. However under
light or no-load conditions this resistor value now causes the
capacitor voltage to discharge significantly as both the leakage
inductance energy and switching frequency are lower. As the
capacitor has to be recharged to above the reflected output
voltage each switching cycle the lower capacitor voltage
represents wasted energy. It has the effect of making the
clamp dissipation appear as a significant load just as if it were
connected to the output of the power supply.
The RZCD arrangement solves this problem by preventing the
voltage across the capacitor discharging below a minimum
value (defined by the voltage rating of VR1) and therefore
minimizing clamp dissipation under light and no-loa d condit ions .
Zener VR1 is shown as a high peak dissipation capable TVS
however a standard lower cost Zener may also be used due to
the low peak current that component experiences.
In many designs a resistor value of less than 50 W may be used
in series with C4 to damp out high frequency ringing and
improve EMI but this was not necessary in this case.
Feedback Configuration
• A high CTR optocoupler was used to reduce secondary bias
currents and no-load input power.
• Low voltage, low current voltage reference IC used on
secondary-side to reduce secondary-side feedback current
and no-load input power.
• Bias winding voltage tuned to ~9 V at no-load, high-line to
reduce no-load input power.
Typically the feedback current into the CONTROL pin at
high-line is ~3 mA. This current is both sourced from the bias
winding (voltage across C10) and directly from the output. Both
of these represent a load on the output of the power supply.
To minimize the dissipation from the bias winding under no-load
conditions the number of bias winding turns and value of C7
was adjusted to give a minimum voltage across C7 of ~9 V.
This is the minimum required to keep the optocoupler biased
and the output in regulation.
To minimize the dissipation of the secondary-side feedback
circuit a high CTR (CTR of 300 – 600%) optocoupler type was
used. This reduces the secondary-side opto-led current from
~3 mA to <~1 mA and therefore the effective load on the output.
A standard 2.5 V TL431 voltage reference was replaced with the
1.24 V LMV431 to reduce the supply current requirement of this
component from 1 mA to 100 mA.
Output Rectifier Choice
• Use of high V
allows the use of a 60 V Schottky diode for
OR
high efficiency and lower cost.
The higher BV
rating of the TOPSwitch-JX of 725 V
DSS
(compared to 600 V or 650 V rating of typical power MOSFETs)
allowed a higher transformer primary to secondary turns ratio
(reflected output voltage or VOR). This reduced the output diode
voltage stress and allowed the use of cheaper and more efficient
60 V (vs 80 V or 100 V) Schottky diodes. The efficiency
improvement occurs due the lower forward voltage drop of the
lower voltage diodes. Two parallel connected axial 5 A, 60 V
Schottky rectifier diodes were selected for both low-cost and
high efficiency. This allowed PCB heat sinking of the diode for
low cost while maintaining efficiency compared to a single
higher current TO-220 packaged diode mounted on a heat sink.
For this configuration the recommendation is that each diode is
rated at twice the output current and that the diodes share a
common cathode PCB area for heat sinking so that their
temperatures track. In practice the diodes current share quite
effectively as can be demonstrated by monitoring their
individual temperatures.
Output Inductor Post Filter Soft-Finish
• Inductor L2 used to provide an output soft-finish and eliminate
a capacitor.
To prevent output overshoot during start-up the voltage
appearing across L2 is used to provide a soft-finish function.
When the voltage across L2 exceeds the forward drop of U2A
and D10 current flows though the optocoupler LED and
provides feedback to the primary. This arrangement acts to
limit the rate of rise of the output voltage until it reaches
regulation and eliminates the capacitor that is typically placed
across U3 to provide the same function.
Key Application Considerations
TOPSwitch-JX vs. TOPSwitch-HX
Table 3 compares the features and performance differences
between TOPSwitch-JX and TOPSwitch-HX. Many of the new
features eliminate the need for additional discrete components.
Other features increase the robustness of design, allowing cost
savings in the transformer and other power components.
TOP264-271 Design Considerations
Power Table
The data sheet power table (Table 1) represents the maximum
practical continuous output power based on the following
conditions:
1. 12 V output.
2. Schottky or high efficiency output diode.
3. 135 V reflected voltage (VOR) and efficiency estimates.
4. A 100 VDC minimum DC bus for 85-265 VAC and 250 VDC
minimum for 230 VAC.
5. Sufficient heat sinking to keep device temperature ≤110 °C.
18
Rev. E 08/12
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Page 19
TOP264-271
TOPSwitch-HX vs. TOPSwitch-JX
Function TOPSwitch-HX TOPSwitch-JX TOPSwitch-JX Advantages
CONTROL current I
0% duty cycle
eDIP-12 / eSOP-12
packages
Breakdown voltage BV
Fast AC reset3 external transistor circuits
Table 3. Comparison Between TOPSwitch-HX and TOPSwitch-JX.
C(OFF)
at
I
= IB + 3.4 mA
C(OFF)
(TOP256-258)
IB = External bias current
Not availableAvailable
Min. 700 V at TJ = 25 °CMin. 725 V at TJ = 25 °C
DSS
using the V pin
I
= IB + 1.6 mA
C(OFF)
(TOP266-268)
1 external transistor circuit
using the X pin
6. Power levels shown in the power table for the V 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.
The provided peak power depends on the current limit for the
respective device.
TOP264-271 Selection
Selecting the optimum TOP264-271 depends upon required
maximum output power, efficiency, heat sinking constraints,
system requirements and cost goals. With the option to
externally reduce current limit, TOP264-271 may be used for
lower power applications where higher efficiency is needed or
minimal heat sinking is available.
Input Capacitor
The input capacitor must be chosen to provide the minimum
DC voltage required for the TOP264-271 converter to maintain
regulation at the lowest specified input voltage and maximum
output power. Since TOP264-271 has a high DC
limit and an
MAX
optimized dual slope line feed forward for ripple rejection, it is
possible to use a smaller input capacitor. For TOP264-271, a
capacitance of 2 mF per watt is possible for universal input with
an appropriately designed transformer.
Primary Clamp and Output Reflected Voltage V
OR
A primary clamp is necessary to limit the peak TOP264-271 drain
to source voltage. A Zener clamp requires few parts and takes
up little board space. F or g ood efficiency, the clamp Zener
should be selected to be at least 1 .5 times the output reflected
voltage VOR, as this keeps the leakage spike conduction 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 t he ra ted breakdown voltage
of the TOP264-271 MOSFET. A high VOR is required to take full
advantage of the wider DC
of TOP264-271. An RCD (or
MAX
RCDZ) clamp provides t i ghter clamp voltage tolerance than a
Zener clamp and allows a VOR as high as 150 V . RCD clamp
• Reduced CONTROL current
• Better no-load performance (<0.1 W)
• Better standby performance
• 66/132 kHz frequency option for DIP style heat sink
dissipation can be minimized by reducing the external current
limit as a function of input line voltage (see Figure 19) . 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 applicati on (including heat
sinking, air circulation, etc.). The higher DC
of TOP264-271,
MAX
along with an appropriate transformer turns ratio, can allow the
use of a 80 V Schottky diode for higher efficiency on output
voltages as high as 15 V.
Bias Winding Capacitor
Due to the low frequency operation at no-load, a bias winding
capacitance of 10 mF minimum is recommended. Ensure a
minimum bias winding voltage of >9 V at zero load for correct
operation and output voltage regulation.
Soft-Start
Generally, a power supply experiences maximum stress at
start-up before the feedback loop achieves regulation. For a
period of 17 ms, the on-chip soft-start linearly increases the
drain peak current and switching frequency from their low
starting values to their respective maximum values. 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 TOP264-271 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. Note that as soon as the
loop closes the soft-start function ceases even if this is prior to
the end of the 17 ms soft-start period.
EMI
The frequency jitter feature modulates the switching fr equency
over a narrow band as a means to reduce conducted EMI peaks
associated with the harmonics of the fundamental swit chi ng
frequency. This is particularly beneficial for average detection
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19
Rev. E 08/12
Page 20
TOP264-271
mode. As can be seen in Figures 27 and 28, the benefits of jitter
increase with the order of the switching harmonic due to an
increase in frequency deviation. The FREQUENCY pin offers a
switching frequency option of 132 kHz or 66 kHz. In applications
that require heavy snubber on the drain node f or r educing high
frequency radiated noise (f or example, video noise sensitive
applications such as VCRs, DVDs, monitors, TVs, 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 1 50 kHz,
above which the conducted EMI specifications get much tighter.
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 an
RCD clamp with current li mit r educt ion wit h line voltage (overload
protection). For designs where operating current is significant ly
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 18).
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. A typical TOP264-271 circuit automatically
enters MCM mode at no-load and the low frequency mode at
light load, which results in extremely low losses under no-load
or standby conditions.
High Power Designs
The TOP264-271 family contains parts that can deliver up to
162 W. High power designs need special considerations.
Guidance for high power designs can be found in the Design
Guide for TOP264-271 (AN-47).
TOP264-271 Layout Considerations
The TOP264-271 has multiple pins and may operate at high
power levels. 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 the 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 VOLTAGE MONITOR (V) pin or
EXTERNAL CURRENT LIMIT (X) pin should also be located
closely between their respective pin and SOURCE. Once again,
the SOURCE connection t ra ce 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 separate trace that is
not shared by t he component s connected to CONTROL ,
VOLTAGE MONITOR or EXTERNAL CURRENT LIMIT pins. This
is because the SOURCE pin is also the controller ground
reference pin. Any traces to the VOLTAGE MONITOR,
EXTERNAL CURRENT LIMIT or CONTROL pins should be kept
as short as possible and away from the DRAIN trace to prevent
noise coupling. Voltage monitor resistors (RLS in Figures 14, 15,
19, 22, 23, 26, 30) and primary-side OVP circuit components
V
in Figures (29, 30) should be located close to the
ZOV/ROV
VOLTAGE MONITOR pin to minimize the trace length on t he
VOL TAGE MONITOR pin side. Resistors connected to the
VOLTAGE MONITOR or EXTERNAL CURRENT LIMIT pin should
be connected as close to the bulk capacitor positive terminal as
possible while routing these connections away from the power
switching circuitry. In addition to the 47 mF CONTROL pin
80
70
60
50
40
30
20
-10
Amplitude (dBµV)
0
-10
-20
0.1511030
EN55022B (QP)
EN55022B (AV)
Frequency (MHz)
Figure 27. Fixed Frequency Operation without Jitter.
80
70
60
50
40
30
20
-10
Amplitude (dBµV)
0
-10
-20
0.1511030
TOPSwitch-JX (with jitter)
EN55022B (QP)
EN55022B (AV)
Frequency (MHz)
Figure 28. TOPSwitch-JX Full Range EMI Scan (132 kHz with Jitter) with
Identical Circuitry and Conditions.
PI-2576-010600
PI-5583-090309
20
Rev. E 08/12
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Page 21
TOP264-271
capacitor, a high frequency bypass capacitor (CBP) in parallel
should be used for better noise immunity. The feedback
optocoupler output should also be located close to the
CONTROL and SOURCE pins of TOP264-271 and away from the
drain and clamp component traces. The primary-side clamp
circuit should be positioned such t hat the loop area fr om t he
transformer end (shar ed with DRAIN) and t he clamp capacit or is
minimized. The bias winding return node should be connected
via a dedicated trace directly to the bulk capacitor and not to
the SOURCE pins. This ensures that surge currents are routed
away from the SOURCE pins of the TOPSwitch-JX.
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. If the Y capacitor is returned to the negative end of
the input bulk capacitor (rather than the positive end) a dedicated
trace must be used to make this connection. This is to “steer”
leakage currents away from the SOURCE pins in case of a
common-mode surge event.
Heat Sinking
The exposed pad of the E package (eSIP-7C), K package
(eSOP-12) and the V package (eDIP-12) are internally electrically
tied to the SOURCE pin. To avoid circulating currents, a heat
sink attached to the exposed pad should not be electrically tied
to any primary ground/source nodes on the PC board. On
double sided boards, top side and bottom side ar eas connect ed
with vias can be used to increase the effective heat sinking
area. The K package exposed pad may be directly soldered to
a copper area for optimum thermal transfer. In addition,
sufficient copper area should be provided at the anode and
cathode leads of the output diode(s) for heat sinking. In Figure
29, 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
In order to reduce the no-load input power of TOP264-271
designs, the VOLTAGE MONITOR pin operates at very low
current. This requires careful layout considerations when
designing the PCB to avoid noise coupling. Traces and
components connected to the VOLTAGE MONITOR pin should
not be adjacent to any traces carrying switching currents.
These include the drain, clamp network, bias winding return or
power traces from other converters. If the line-sensing features
are used, then the sense resistors must be placed within 10 mm
of the VOLTAGE MONITOR pin to minimize the VOLTAGE
MONITOR pin node area. The DC bus should then be routed to
the line-sense resistors. Note that external capacitance must
not be connected to the VOLTAGE MONITOR pin as this may
cause misoperation of the VOLTAGE MONITOR pin related
functions. As with any power supply design, all TOP264-271
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.
TOP264-271 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 34) for the drain current waveform
at the end of the 220 ns blanking period.
3. Thermal check – At maximum output power, both minimum
and maximum voltage and ambient temperature; verify that
temperature specifications are not exceeded for TOP264271, transformer, output diodes and output capacitors.
Enough thermal margin should be allowed for the part-topart variation of the R
of TOP264-271, as specified in
DS(ON)
the data sheet. The margin required can either be calculated
from the values in the parameter table or it can be accounted
for by connecting an external resistance in series with the
DRAIN pin and attached to the same heat sink, 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 website: www.powerint.com
www.powerint.com
21
Rev. E 08/12
Page 22
TOP264-271
Maximize Copper Area
for Optimum Heat Sinking
DC
–
OUT
+
RLS1
RPL1
DC
IN
+–
J1
Input Filter
C4
U1
RIL
CBP
RPL2
RLS2
VZOV
R12
C10
ROV
CB
DB
R16
R5D5
C3
Clamp Circuit
VR1
U2
T1
Transformer
C11
Capacitor
Figure 29. Layout Considerations for TOPSwitch-JX using V Package and Operating at 132 kHz.
U3
Output Filter
Capacitors
Output
Rectifiers
Y-
Capacitor
J2
C16
C18
L2
C17
D8
D9
HF LC
Post-Filter
PI-5752-061311
Maximize Copper Area
for Optimum Heat Sinking
J1
DC
IN
+–
Input Filter
Capacitor
C4
U1
RPL1
RIL
RLS1
RIL
CBP
DC
+
–
OUT
J2
CB+
ROV
RPL2
RLS2
C10
DB
VZOV
R12
R16CBP
U2
T1
Output Filter
Capacitors
Transformer
U3
C17
C18
C16
L2
HF LC
Post-Filter
Output
D8
D9
D5
C3
R5
VR1
C11
Rectiers
Y-
Capacitor
Clamp Circuit
PI-6173-081412
Figure 30. Layout Considerations for TOPSwitch-JX using K Package and Operating at 132 kHz.
22
Rev. E 08/12
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Page 23
TOP264-271
HV
+
-
Input Filter
Capacitor
J1
C4
RLS2
RLS1
RPL1
CBP
ROV
Clamp
Circuit
HS1
S
C
V
Isolation Barrier
Y-
Capacitor
C16R12
D8
HS2
Output
R6
D5
C6
R7
T1
Rectifier
U1
D
F
X
VR1
C9
RIL
Transformer
C17
L3
Output Filter
Capacitors
HF LC
Post-Filter
PI-5793-030910
RPL2
R8
VZOV
DB
R9
R10
CB
JP2
U2
R15
U4
R17
R13
C21
C18
R21
R20
OUT
DC
C19
J2
+-
Figure 31. Layout Considerations for TOPSwitch-JX using E Package and Operating at 132 kHz.
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23
Rev. E 08/12
Page 24
TOP264-271
Absolute Maximum Ratings
(2)
DRAIN Pin Peak Voltage .....................................-0.3 V to 725 V
DRAIN Pin Peak Current: TOP264 ................................... 2.08 A
DRAIN Pin Peak Current: TOP265 ................................... 2.72 A
DRAIN Pin Peak Current: TOP266 ................................... 4.08 A
DRAIN Pin Peak Current: TOP267 ................................... 5.44 A
DRAIN Pin Peak Current: TOP268 ................................... 6.88 A
DRAIN Pin Peak Current: TOP269 ................................... 7.73 A
DRAIN Pin Peak Current: TOP270 ................................... 9.00 A
DRAIN Pin Peak Current: TOP271 ................................. 11.10 A
CONTROL Pin Voltage ............................................-0.3 V to 9 V
CONTROL Pin Current .................................................. 100 mA
VOLTAGE MONITOR Pin Voltage ...........................-0.3 V to 9 V
CURRENT LIMIT Pin Voltage ..............................-0.3 V to 4.5 V
FREQUENCY Pin Voltage ......................................-0.3 V to 9 V
Storage Temperature ...................................... -65 °C to 150 °C
Operating Junction Temperature ......................-40 °C to 150 °C
Lead Temperature
(1)
........................................................260 °C
Notes:
1. 1/16 in. from case for 5 seconds.
2. Maximum ratings specified may be applied one at a time
without causing permanent damage to the product. Expo
sure to Absolute Maximum Rating conditions for extended
periods of time may affect product reliability.
Notes:
(1)
1. Free standing with no heat sink.
(2)
2. Measured at the back surface of tab.
3. Soldered (including exposed pad for K package) to typical
(4)
application PCB with a heat sinking area of 0.36 sq. in. (232mm2),
(2)
2 oz. (610 g/m2) copper clad.
4. Soldered (including exposed pad for K package) to typical
application PCB with a heat sinking area of 1 sq. in. (645 mm2),
NOTES:
A. Derived during test from the parameters DC
B. 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.
C. Guaranteed by characterization. Not tested in production.
D. For externally adjusted current limit values, please refer to Figures 36 and 37 (Current Limit vs. External Current Limit Resistance)
in the Typical Performance Characteristics section. The tolerance specified is only valid at full current limit.
E. I2f calculation is based on typical values of I
pin connection. See f
specification for detail.
OSC
F. The device will start up at 18 VDC drain voltage. The capacitance of electrolytic capacitors drops significantly at temperatures below
0 °C. For reliable start-up at 18 V in sub-zero temperatures, designers must ensure that circuit capacitors meet recommended
capacitance values.
G. Breakdown voltage may be checked against minimum BV
minimum BV
DSS
.
LIMIT
, IB and I
MAX
and f
OSC,
at 132 kHz.
C(OFF)
i.e. I
2
× f
LIMIT(TYP)
specification by ramping the DRAIN pin voltage up to but not exceeding
DSS
, where f
OSC
= 66 kHz or 132 kHz depending on FREQUENCY
OSC
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29
Rev. E 08/12
Page 30
TOP264-271
CONTROL Pin Current (mA)
DRAIN Current (normalized)
HV
90%
t
2
t
1
90%
DRAIN
VOLTAGE
D =
t
1
t
2
10%
0 V
PI-2039-033001
Figure 32. Duty Cycle Measurement.
t
(Blanking Time)
120
1.3
1.2
100
80
60
40
20
Dynamic
Impedance
=
PI-4737-061207
1
Slope
1.1
1.0
0.9
0.8
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
56789
CONTROL Pin Voltage (V)
Figure 33. CONTROL Pin I-V Characteristic.Figure 34. Drain Current Operating Envelope.
LEB
I
INIT(MIN)
012683
457
Time (µs)
PI-4758-061407
Figure 35. TOPSwitch-JX General Test Circuit.
30
Rev. E 08/12
(X and V Pins)
S1
40 V
0-15 V
NOTES: 1. This test circuit is not applicable for current limit or output characteristic measurements.
470 Ω
470 Ω
5 W
S2
5-50 V
0-300 kΩ
0.1 µF47 µF
S4
CONTROL
C
0-60 kΩ
V
S3
D
C
SFX
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Page 31
PI-5581-090309
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
-200-150-100-500
Normalized Current Limit
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
t
Typical
Notes:
1. Maximum and Minimum levels are
based on characterization.
2. T
J
= 0 OC to 125 OC.
Minimum
Maximum
Normalized Current Limit
Normalized di/dt
IX ( µA )
PI-5582-090309
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
051015202530354045
R
IL
( kΩ )
Normalized Current Limit (A)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
Normalized di/dt (mA/
µ
s)
Notes:
1. Maximum and Minimum levels are
based on characterization.
2. T
J
= 0 OC to 125 OC.
3. Includes the variation of X pin voltage.
Typical
Maximum
Minimum
Normalized Current Limit
Normalized di/dt
Typical Performance Characteristics
Figure 36. Normalized Current Limit vs. X Pin Current.
TOP264-271
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Figure 37. Normalized Current Limit vs. External Current Limit Resistance.
31
Rev. E 08/12
Page 32
TOP264-271
Junction Temperature (°C)
Breakdown Voltage
(Normalized to 25
Junction Temperature (°C)
Output Frequency
(Normalized to 25
Junction Temperature (°C)
(Normalized to 25
1.2
PI-4739-061507
(Normalized to 25
Junction Temperature (°C)
Overvoltage Threshold
(Normalized to 25
Junction Temperature (°C)
Undervoltage Threshold
(Normalized to 25
Typical Performance Characteristics (cont.)
1.1
PI-176B-033001
°C)
1.2
1.0
°C)
0.8
1.0
0.6
0.4
0.2
0.9
-50 -25025 50 75 100 125 150
Figure 38. Breakdown Voltage vs. Temperature.Figure 39. Frequency vs. Temperature.
0
-50 -25025 50 75 100 125 150
1.2
1.0
ϒC)
0.8
0.6
°C)
1.0
0.8
0.6
PI-4760-061407
PI-4759-061407
0.4
Current Limit
0.2
0
-50 -25025 50 75 100 125 150
Figure 40. Internal Current Limit vs. Temperature.
1.2
1.0
°C)
0.8
0.6
0.4
0.2
0
-50 -25 025 50 75 100 125 150
PI-4761-061407
0.4
Current Limit
0.2
0
-50 -25 0255075 100 125 150
Junction Temperature (°C)
Figure 41. External Current Limit vs. Temperature with RIL = 10.5 kW.
1.2
1.0
°C)
0.8
0.6
0.4
0.2
0
-50 -25025 50 75 100 125 150
PI-4762-100610
Figure 42. Overvoltage Threshold vs. Temperature.
32
Rev. E 08/12
Figure 43. Undervoltage Threshold vs. Temperature.
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Page 33
Typical Performance Characteristics (cont.)
VOLTAGE MONITOR Pin Voltage (V)
EXTERNAL CURRENT LIMIT
CONTROL Current
(Normalized to 25
Onset Threshold Current
(Normalized to 25
Drain Pin Voltage (V)
CONTROL Pin Current (mA)
Drain Voltage (V)
DRAIN Current (A)
TOP264-271
6
5.5
5
4.5
4
3.5
3
2.5
2
0100200500400300
VOLTAGE-MONITOR Pin Current (µA)
Figure 44. VOLTAGE-MONITOR Pin vs. Current.
1.2
1.0
°C)
0.8
0.6
PI-4740-060607
PI-4763-072208
1.6
VX = 1.354 - 1147.5 × IX + 1.759 × 106 ×
1.4
)2 with -180 µA < I
(I
X
< -25 µA
X
1.2
1.0
0.8
0.6
Pin Voltage (V)
0.4
0.2
0
-200-150-50-1000
EXTERNAL CURRENT LIMIT Pin Current (µA)
Figure 45. EXTERNAL CURRENT LIMIT Pin Voltage vs. Current.
1.2
1.0
°C)
0.8
0.6
PI-4741-110907
PI-4764-061407
0.4
0.2
0
-50 -25025 50 75 100 125 150
Junction Temperature (°C)
Figure 46. Control Current Out at 0% Duty Cycle vs. Temperature.
Figure 52. Remote-OFF DRAIN Supply Current vs. Temperature.
34
Rev. E 08/12
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Page 35
eSIP-7C (E Package)
TOP264-271
2
0.403 (10.24)
A
0.397 (10.08)
B
2
0.325 (8.25)
0.320 (8.13)
Pin #1
I.D.
0.070 (1.78) Ref.
0.050 (1.27)
FRONT VIEW
10° Ref.
All Around
0.378 (9.60)
Ref.
END VIEW
Notes:
1. Dimensioning and tolerancing per ASME Y14.5M-1994.
2. Dimensions noted are determined at the outermost
extremes of the plastic body exclusive of mold flash,
tie bar burrs, gate burrs, and interlead flash, but including
any mismatch between the top and bottom of the plastic
body. Maximum mold protrusion is 0.007 [0.18] per side.
3. Dimensions noted are inclusive of plating thickness.
4. Does not include inter-lead flash or protrusions.
1. Dimensioning and tolerancing per
ASME Y14.5M-1994.
most extremes of the plastic body exclusive of
mold flash, tie bar burrs, gate burrs, and interlead
top and bottom of the plastic body. Maximum
mold protrusion is 0.007 [0.18] per side.
3. Dimensions noted are inclusive of plating
thickness.
4. Does not include inter-lead flash or protrusions.
5. Controlling dimensions in inches [mm].
6. Datums A and B to be determined at Datum H.
7. Measured with the leads constrained to be
perpendicular to Datum C.
8. Measured with the leads unconstrained.
9. Lead numbering per JEDEC SPP-012.
10. Exposed pad is nominally located at the center line of Datums A and B. “Max” dimensions
noted include both size and positional tolerances.
0.023 [0.58]
0.018 [0.46]
0.010 [0.25] M C A B
BOTTOM VIEW
0.059 [1.50]
Ref, typ.
3 4
11×
PI-5556a-100311
36
Rev. E 08/12
Page 37
Pin #1 I.D.
(Laser Marked)
0.460 [11.68]
0.400 [10.16]
2
0.004 [0.10] C A 2X
0.059 [1.50]
Ref, Typ
0.059 [1.50]
eSOP-12B (K Package)
0.356 [9.04]
0.325 [8.26]
Max.
712
Ref, Typ
2X
0.004 [0.10] C B
0.350 [8.89]
2
Ref.
7
0.055 [1.40] Ref.
0.225 [5.72]
Max.
0.010 [0.25]
7
TOP264-271
°
°
8
0 -
0.034 [0.85]
0.026 [0.65]
DETAIL A (Scale = 9X)
0.010 [0.25]
Ref.
Gauge Plane
Seating Plane
H
C
0.008 [0.20] C
2X, 5/6 Lead Tips
0.098 [2.49]
0.086 [2.18]
0.006 [0.15]
0.000 [0.00]
Seating plane to
package bottom
standoff
0.028 [0.71]
1
2
0.067 [1.70]
1
2
3
4
6
3 4661
0.023 [0.58]
0.018 [0.46]
11×
3 4
0.010 (0.25) M C A B
B
0.120 [3.05] Ref
0.070 [1.78]
TOP VIEWBOTTOM VIEW
0.032 [0.80]
0.029 [0.72]
0.092 [2.34]
0.086 [2.18]
Seating
0.004 [0.10] C
SIDE VIEW
C
Detail A
0.306 [7.77]
Ref.
END VIEW
Plane
Land Pattern
0.217 [5.51]
Dimensions
Notes:
1. Dimensioning and tolerancing per ASME Y14.5M-1994.
12
2. Dimensions noted are determined at the outermost
extremes of the plastic body exclusive of mold flash,
11
tie bar burrs, gate burrs, and interlead flash, but
including any mismatch between the top and bottom of
the plastic body. Maximum mold protrusion is 0.007
10
0.321 [8.15]
9
[0.18] per side.
3. Dimensions noted are inclusive of plating thickness.
4. Does not include interlead flash or protrusions.
5. Controlling dimensions in inches [mm].
8
6. Datums A and B to be determined at Datum H.
7. Exposed pad is nominally located at the centerline of
7
Datums A and B. “Max” dimensions noted include both
size and positional tolerances.
0.429 [10.90]
0.028 [0.71]
Ref.
3
0.016 [0.41]
0.011 [0.28]
11×
0.020 [0.51]
Ref.
0.049 [1.23]
0.046 [1.16]
0.019 [0.48]
Ref.
0.022 [0.56]
Ref.
PI-5748a-100311
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37
Rev. E 08/12
Page 38
TOP264-271
Part Ordering Information
TOP 264 E G - TL
38
Rev. E 08/12
• TOPSwitch Product Family
• JX Series Number
• Package Identier
E Plastic eSIP-7C
V Plastic eDIP-12
K Plastic eSOP-12
• Pin Finish
G Halogen Free and RoHS Compliant
• Tape & Reel and Other Options
Blank Standard Configurations
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Page 39
TOP264-271
RevisionNotesDate
ARelease data sheet.01/10
BAdded eDIP parts.01/10
BPage 4 “latching” changed to “hysteretic”. Table 3 updated.03/10
BSentence in ‘Line-Sense Resistor Values’ section updated.07/10
CAdded K package parts.11/10
DUpdated K and V package drawings.06/11
EAdded eDIP-12B and eSOP-12B packages. Removed eDIP-12 and eSOP-12 packages.10/11
EUpdated Figure 2 and K package layout.08/12
www.powerint.com
39
Rev. E 08/12
Page 40
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