Datasheet MC33365P Datasheet (MOTOROLA)

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The MC33365 is a monolithic high voltage switching regulator that is specifically designed to operate from a rectified 240 Vac line source. This integrated circuit features an on–chip 700 V/1.0 A SenseFET power switch, 450 V active off–line startup FET, duty cycle controlled oscillator, current limiting comparator with a programmable threshold and leading edge blanking, latching pulse width modulator for double pulse suppression, high gain error amplifier, and a trimmed internal bandgap reference. Protective features include cycle–by–cycle current limiting, input undervoltage lockout with hysteresis, bulk capacitor voltage sensing, and thermal shutdown. This device is available in a 16–lead dual–in–line package.

• On–Chip 700 V, 1.0 A SenseFET Power Switch

• Rectified 240 V ac Line Source Operation

• On–Chip 450 V Active Off–Line Startup FET

• Latching PWM for Double Pulse Suppression

• Cycle–By–Cycle Current Limiting

• Input Undervoltage Lockout with Hysteresis

• Bulk Capacitor Voltage Comparator

• Trimmed Internal Bandgap Reference

• Internal Thermal Shutdown

HIGH VOLTAGE

OFF–LINE

SWITCHING REGULATOR

SEMICONDUCTOR

TECHNICAL DATA

16

1

P SUFFIX

PLASTIC PACKAGE

CASE 648E

(DIP–16)

AC Input

Regulator

Output

8

6

R

T

C

7

T

Mirror

Osc

PWM

Thermal

Gnd 4, 5, 12, 13

Simplified Application

Startup Input

Startup

Reg

PWM Latch

Driver

S

Q

R

I

pk

LEB

EA

1

UVLO

BOK

V

CC

3

BOK

11 16

Power Switch Drain

Compensation

9

10

Voltage Feedback Input

DC Output

PIN CONNECTIONS

Startup Input

V

CC

Gnd

R

T

C

T

Regulator Output

ORDERING INFORMATION

Device

116

3 4 5 6 7 8

(Top View)

Operating

Temperature Range

Power Switch Drain

13

Gnd

12

BOK

11

Voltage Feedback

10

Input Compensation

9

Package

MOTOROLA ANALOG IC DEVICE DATA

MC33365P DIP–16

 Motorola, Inc. 1999 Rev 1

TJ = –25° to +125°C

1

MAXIMUM RATINGS

Á

ÁÁÁ

ÁÁÁ ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

Rating Symbol Value Unit

Power Switch (Pin 16)

Drain Voltage

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Drain Current

Startup Input Voltage (Pin 1, Note 1)

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Pin 3 = Gnd Pin 3 ≤ 1000 µF to ground

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Power Supply Voltage (Pin 3) Input Voltage Range

Voltage Feedback Input (Pin 10)

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Compensation (Pin 9) Bulk OK Input (Pin 11)

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RT (Pin 6)

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CT (Pin 7)

Thermal Characteristics

P Suffix, Dual–In–Line Case 648E

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Thermal Resistance, Junction–to–Air Thermal Resistance, Junction–to–Case

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Operating Junction Temperature Storage Temperature

NOTE: ESD data available upon request.

V

DS

ÁÁ

I

DS

V

in

ÁÁ

V

CC

V

IR

ÁÁ

R

θJA

R

ÁÁ

θJC T

J

T

stg

MC33365

700

ÁÁÁ

400 500

ÁÁÁ

–1.0 to V

ÁÁÁ

–25 to +150 –55 to +150

1.0

40

80 15

reg

V

Á

A V

Á

V V

Á

°C/W

Á

°C °C

ELECTRICAL CHARACTERISTICS (V

= 20 V, RT = 10 k, CT = 390 pF, C

CC

= 1.0 µF, for typical values TJ = 25°C,

Pin 8

for min/max values TJ is the operating junction temperature range that applies (Note 2), unless otherwise noted.)

Characteristic

Symbol Min Typ Max Unit

REGULAT OR (Pin 8)

Output Voltage (IO = 0 mA, TJ = 25°C) Line Regulation (VCC = 20 V to 40 V) Load Regulation (IO = 0 mA to 10 mA) Total Output Variation over Line, Load, and Temperature

V

Reg

V

reg

load

reg

line

5.5

5.3

6.5 – –

30 44

–

7.5 500 200

8.0

V mV mV

V

OSCILLAT OR (Pin 7)

Frequency

CT = 390 pF

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TJ = 25°C (VCC = 20 V) TJ = T

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CT = 2.0 nF

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TJ = 25°C (VCC = 20 V) TJ = T

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Frequency Change with Voltage (VCC = 20 V to 40 V)

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ERROR AMPLIFIER (Pins 9, 10)

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Voltage Feedback Input Threshold

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Line Regulation (VCC = 20 V to 40 V, TJ = 25°C)

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Input Bias Current (VFB = 2.6 V, TJ = 0 – 125°C)

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Open Loop Voltage Gain (TJ = 25°C)

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Gain Bandwidth Product (f = 100 kHz, TJ = 25°C)

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Output Voltage Swing

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High State (I Low State (I

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NOTES: 1. Maximum power dissipation limits must be observed.

low

to T

(VCC = 20 V to 40 V)

high

(VCC = 20 V to 40 V)

high

= 100 µA, VFB < 2.0 V)

Source

= 100 µA, V

Sink

> 3.0 V)

FB

2.Tested junction temperature range for the MC33363B: T

= –25°CT

low

high

= +125°C

f

OSC

ÁÁÁ

∆f

/∆V

OSC

ÁÁÁ

V

FB

ÁÁÁ

Reg

line

ÁÁÁ

I

IB

ÁÁÁ

A

VOL

ÁÁÁ

GBW

ÁÁÁ

V

OH

V

ÁÁÁ

OL

ÁÁ

260 255

ÁÁ

60 59

ÁÁ

–

ÁÁ

2.52

ÁÁ

ÁÁ–ÁÁ

–

ÁÁ

70

ÁÁ

0.85

ÁÁ

4.0 –

ÁÁ

285

–

ÁÁ

67.5 –

ÁÁ

0.1

ÁÁ

2.6

ÁÁ

0.6 20

ÁÁ

82

ÁÁ

1.0

ÁÁ

5.3

0.2

ÁÁ

310 315

ÁÁ

75 76

ÁÁ

2.0

ÁÁ

2.68

ÁÁ

5.0

ÁÁ

500

ÁÁ

94

ÁÁ

1.15

ÁÁ

–

0.35

ÁÁ

kHz

ÁÁ

kHz

ÁÁ

V

ÁÁ

mV

ÁÁ

nA

ÁÁ

dB

ÁÁ

MHz

ÁÁ

V

ÁÁ

2

MOTOROLA ANALOG IC DEVICE DATA

MC33365

ÁÁÁ

ÁÁÁ ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á

ÁÁÁ

Á ÁÁÁ

ÁÁÁ

Á

ÁÁÁ

Á ÁÁÁ

ÁÁÁ ÁÁÁ

Á

ÁÁÁ

Á

ELECTRICAL CHARACTERISTICS (continued) (V

= 20 V, RT = 10 k, CT = 390 pF, C

CC

= 1.0 µF, for typical values TJ = 25°C,

Pin 8

for min/max values TJ is the operating junction temperature range that applies (Note 2), unless otherwise noted.)

Characteristic UnitMaxTypMinSymbol

BULK OK (Pin 11)

Input Threshold Voltage Input Bias Current (VBK < Vth, TJ = 0 – 125°C) Source Current (Turn on after VBK > Vth, TJ = 25°C – 125°C)

V

I

IB

SC

th

1.18 –

1.25 100

39

PWM COMPARATOR (Pins 7, 9)

Duty Cycle

Maximum (VFB = 0 V)

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Minimum (VFB = 2.7 V)

DC

(max)

ÁÁÁ

DC

(min)

48

ÁÁ

–

ÁÁ

POWER SWITCH (Pin 16)

Drain–Source On–State Resistance (ID = 200 mA)

TJ = 25°C

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TJ = T

low

to T

high

Drain–Source Off–State Leakage Current

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VDS = 650 V Rise Time Fall Time

R

DS(on)

ÁÁÁ

I

D(off)

ÁÁÁ

t

r

t

f

–

ÁÁ

–

ÁÁ

– – –

ÁÁ

OVERCURRENT COMPARATOR (Pin 16)

Current Limit Threshold (RT = 10 k)

I

lim

0.5

0.72

STARTUP CONTROL (Pin 1)

Peak Startup Current (Vin = 400 V) (Note 3)

VCC = 0 V

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VCC = (V

th(on)

– 0.2 V)

Off–State Leakage Current (Vin = 50 V, VCC = 20 V)

I

start

ÁÁÁ

I

D(off)

–

ÁÁ

– –

ÁÁ

UNDERVOLTAGE LOCKOUT (Pin 3)

Startup Threshold (VCC Increasing) Minimum Operating Voltage After Turn–On

V

th(on)

V

CC(min)

11

7.5

15.2

TOTAL DEVICE (Pin 3)

Power Supply Current

Startup (V

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Operating

NOTES: 3. The device can only guarantee to start up at high temperature below +115°C.

= 10 V, Pin 1 Open)

CC

I

CC

ÁÁÁ

–

ÁÁ

–

0.25

ÁÁ

50

15

0.2 50 50

2.0

2.0 40

9.5

3.2

1.32 500

–

53

V nA µA

%

52

0

ÁÁ

0

Ω

17

–

ÁÁ

39

ÁÁ

µA

ÁÁ

100

– –

0.9

ÁÁ

ns ns

A

mA

4.0

ÁÁ

11.5

4.0

200

18

ÁÁ

µA

V

mA

0.5

ÁÁ

5.0

ÁÁ

Figure 1. Oscillator Frequency

versus Timing Resistor

1.0 M

CT = 100 pF

500 k

CT = 200 pF

CT = 500 pF

200 k

CT = 1.0 nF

100 k

CT = 2.0 nF

50 k

, OSCILLAT OR FREQUENCY (Hz)

CT = 5.0 nF

20 k

OSC

f

CT = 10 nF

10 k

7.0

10 15 20 30 50

RT, TIMING RESISTOR (kΩ)

MOTOROLA ANALOG IC DEVICE DATA

VCC = 20 V

°

C

TA = 25

70

Figure 2. Power Switch Peak Drain Current

versus Timing Resistor

1.0

0.8

0.6

0.4

0.3

0.2

0.15

Inductor supply voltage and inductance value are adjusted so that Ipk turn–off is achieved at 5.0

, POWER SWITCH PEAK DRAIN CURRENT (A)

0.1

PK

7.0 10 15 20 30 40 7050

I

RT, TIMING RESISTOR (kΩ)

µ

s.

VCC = 20 V

µ

CT = 1.0 TA = 25

F

°

C

3

0.8

0.5

Figure 3. Oscillator Charge/Discharge

Current versus Timing Resistor

VCC = 20 V TA = 25

MC33365

°

C

Figure 4. Maximum Output Duty Cycle

versus Timing Resistor Ratio

70

60

RD/RT Ratio Discharge Resistor Pin 6 to Gnd

VCC = 20 V CT = 2.0 nF

°

C

TA = 25

0.3

, OSCILLAT OR

0.2

dscg

/I

0.15

chg

I

0.1

CHARGE/DISCHARGE CURRENT (mA)

0.08

7.0

100

80

60

40

20

, OPEN LOOP VOL TAGE GAIN (dB)

0

VOL

A

–20

10

50

40

, MAXIMUM OUTPUT DUTY CYCLE (%)

max

D

, OUTPUT SA TURATION VOLTAGE (V) V

sat

30

–1.0

– 2.0

2.0

1.0

1.0 TIMING RESISTOR RA TIO

Figure 6. Error Amp Output Saturation

V oltage versus Load Current

0

Source Saturation

(Load to Ground)

Sink Saturation

(Load to V

0

IO, OUTPUT LOAD CURRENT (mA)

ref

)

10 15 20 30 70 2.0 3.0 5.0 7.0 10

RT, TIMING RESISTOR (kΩ)

50

Figure 5. Error Amp Open Loop Gain and

Phase versus Frequency

VCC = 20 V VO = 1.0 to 4.0 V

Gain

Phase

100 1.0 k 10 k 100 k 1.0 M 10 M 0.2 0.4 0.6 0.8 1.0

f, FREQUENCY (Hz)

RL = 5.0 M CL = 2.0 pF TA = 25

Ω

°

C

0

30

60

90

120

, EXCESS PHASE (DEGREES)

θ

150

180

RC/RT Ratio Charge Resistor Pin 6 to V

V

ref

VCC = 20 V TA = 25

Gnd

°

reg

C

1.80 V

1.75 V

1.70 V

4

Figure 7. Error Amplifier Small Signal

Transient Response

VCC = 20 V AV = –1.0 CL = 10 pF TA = 25

1.0 µs/DIV

Figure 8. Error Amplifier Large Signal

Transient Response

VCC = 20 V AV = –1.0

°

C

20 mV/DIV

3.00 V

1.75 V

0.50 V

1.0 µs/DIV

CL = 10 pF

°

C

TA = 25

0.5 V/DIV

MOTOROLA ANALOG IC DEVICE DATA

–20

MC33365

Figure 9. Regulator Output Voltage

Change versus Source Current

0

VCC = 20 V RT = 10 k C

= 1.0

Pin 8

°

C

TA = 25

µ

F

2.0

Figure 10. Peak Startup Current

versus Power Supply V oltage

V

Pin 1

TA = 25

= 400 V

°

C

–40

–60

, REGULAT OR VOLTAGE CHANGE (mV)

reg

V

–80

∆

0

4.0 8.0 12 16 20 2.0 4.0 6.0 8.0 10 12 14

I

reg

Figure 11. Power Switch Drain–Source

Ω

32

24

16

8.0

, DRAIN–SOURCE ON–RESISTANCE ( )

0

DS(on)

R

–50

On–Resistance versus T emperature

ID = 200 mA

–25 0 25 50 75 150100 10 100 1000

, REGULAT OR SOURCE CURRENT (mA)

Pulse tested at 5.0 ms with < 1.0% duty cycle so that TJ is as close to TA as possible.

125

TA, AMBIENT TEMPERATURE (°C)

1.0

Pulse tested with an on–time of 20 µs to 300 µs

, PEAK STARTUP CURRENT (mA)

at < 1.0% duty cycle. The on–time is adjusted at

pk

Pin 1 for a maximum peak current out of Pin 3.

I

0

VCC, POWER SUPPLY VOLTAGE (V)

Figure 12. Power Switch

Drain–Source Capacitance versus V oltage

160

120

80

40

, DRAIN–SOURCE CAPACITANCE (pF)

C

OSS

C

0

1.0

measured at 1.0 MHz with 50 mVpp.

OSS

VDS, DRAIN–SOURCE VOLTAGE (V)

VCC = 20 V

°

C

TA = 25

Figure 13. Supply Current versus Supply V oltage

3.2

2.4

1.6

, SUPPLY CURRENT (mA)

0.8

CC

I

0

10 20 30 40

VCC, SUPPLY VOLTAGE (V)

CT = 390 pF

CT = 2.0 nF

RT = 10 k Pin 1 = Open Pin 4, 5, 10, 11, 12, 13 = Gnd TA = 25

MOTOROLA ANALOG IC DEVICE DATA

Figure 14. DW and P Suffix Transient

Thermal Resistance

100

L = 12.7 mm of 2.0 oz. copper. Refer to Figure 15.

°

10

, THERMAL RESISTANCE

JA

JUNCTION–TO–AIR ( C/W)

θ

R

°

C

1.0

0.01

0.1 1.0 10 100 t, TIME (s)

5

MC33365

Á

Figure 15. P Suffix (DIP–16) Thermal Resistance and

Maximum Power Dissipation versus P.C.B. Copper Length

100

Printed circuit board heatsink example

5.0

80

°

60

R

θ

JA

2.0 oz

L

Copper

L

Graphs represent symmetrical layout

40

JA

20

θ

JUNCTION–TO–AIR ( C/W)

R , THERMAL RESISTANCE

0

P

for TA = 70°C

D(max)

10 20 30 40 50

L, LENGTH OF COPPER (mm)

PIN FUNCTION DESCRIPTION

Pin Function Description

1

ÁÁÁ

2

ÁÁÁ

3

ÁÁÁ

4, 5, 12, 13

ÁÁÁ

6

ÁÁÁ

7

ÁÁÁ

8

ÁÁÁ

9

10

ÁÁÁ

11

14, 15

ÁÁÁ

16

ÁÁÁ

Startup Input

ÁÁÁÁ

–

ÁÁÁÁ

V

CC

ÁÁÁÁ

Ground

ÁÁÁÁ

R

T

ÁÁÁÁ

C

T

ÁÁÁÁ

Regulator Output

ÁÁÁÁ

Compensation

Voltage Feedback

ÁÁÁÁ

Input

ÁÁÁÁ

Bulk OK Input

–

ÁÁÁÁ

Power Switch Drain

ÁÁÁÁ

This pin connects directly to the rectified ac line voltage source. Internally Pin 1 is tied to the drain

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of a high voltage startup MOSFET. During startup, the MOSFET supplies internal bias, and charges an external capacitor that connects from the V

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This pin has been omitted for increased spacing between the rectified ac line voltage on Pin 1 and the V

potential on Pin 3.

CC

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This is the positive supply voltage input. During startup, power is supplied to this input from Pin 1.

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When VCC reaches the UVLO upper threshold, the startup MOSFET turns off and power is supplied from an auxiliary transformer winding.

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These pins are the control circuit grounds. They are part of the IC lead frame and provide a thermal path from the die to the printed circuit board.

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Resistor RT connects from this pin to ground. The value selected will program the Current Limit

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Comparator threshold and affect the Oscillator frequency. Capacitor C

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programs the Oscillator frequency.

connects from this pin to ground. The value selected, in conjunction with resistor R

T

This 6.5 V output is available for biasing external circuitry. It requires an external bypass capacitor of at least 1.0 µF for stability.

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This pin is the Error Amplifier output and is made available for loop compensation. It can be used as an input to directly control the PWM Comparator.

This is the inverting input of the Error Amplifier. It has a 2.6 V threshold and normally connects

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through a resistor divider to the converter output, or to a voltage that represents the converter output.

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This is the non–inverting input of the bulk capacitor voltage comparator. It has an input threshold voltage of 1.25V. This pin is connected through a resistor divider to the bulk capacitor line voltage.

These pins have been omitted for increased spacing between the high voltages present on the

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Power Switch Drain, and the ground potential on Pins 12 and 13. This pin is designed to directly drive the converter transformer and is capable of switching a

maximum of 700 V and 1.0 A.

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3.0 mm

pin to ground.

CC

4.0

3.0

2.0

1.0

0

, MAXIMUM POWER DISSIPATION (W)

D

P

,

T

6

MOTOROLA ANALOG IC DEVICE DATA

AC Input

MC33365

Figure 16. Representative Block Diagram

Regulator Output

6.5 V

8

6

R

T

C

7

T

I

Current

Mirror

4 I

Oscillator

PWM

Comparator

Thermal

Shutdown

2.25 I

Band Gap Regulator

PWM Latch

Current Limit

Comparator

4, 5, 12, 13Gnd

S

Q

R

405

270µA

Startup Input

Startup Control

UVLO

Driver

Leading Edge

Blanking

Error

Amplifier

1

14.5 V/

9.5 V

1.25 V

2.6 V

V

CC 3

BOK

11

16

Power Switch

Drain

8.1 Compensation

9

10 Voltage

Feedback Input

DC Output

Capacitor C

Compensation

Oscillator Output

Power Switch

Leading Edge Blanking Input (Power Switch Drain Current)

T

PWM

Comparator

Output

PWM Latch

Q Output

Gate Drive

Figure 17. Timing Diagram

2.6 V

0.6 V

Current Limit Propagation Delay

Current Limit Threshold

Normal PWM Operating Range Output Overload

MOTOROLA ANALOG IC DEVICE DATA

7

MC33365

OPERA TING DESCRIPTION

Introduction

The MC33365 represents a new higher level of integration by providing all the active high voltage power, control, and protection circuitry required for implementation of a flyback or forward converter on a single monolithic chip. This device is designed for direct operation from a rectified 240 Vac line source and requires a minimum number of external components to implement a complete converter. A description of each of the functional blocks is given below, and the representative block and timing diagrams are shown in Figures 16 and 17.

Oscillator and Current Mirror

The oscillator frequency is controlled by the values selected for the timing components R programs the oscillator charge/discharge current via the Current Mirror 4 I output, Figure 3. Capacitor CT is charged and discharged by an equal magnitude internal current source and sink. This generates a symmetrical 50 percent duty cycle waveform at Pin 7, with a peak and valley threshold of 2.6 V and 0.6 V respectively. During the discharge of C pulse that holds the inverting input of the AND gate Driver high. This causes the Power Switch gate drive to be held in a low state, thus producing a well controlled amount of output deadtime. The amount of deadtime is relatively constant with respect to the oscillator frequency when operating below

1.0 MHz. The maximum Power Switch duty cycle at Pin 16 can be modified from the internal 50% limit by providing an additional charge or discharge current path to CT, Figure 18. In order to increase the maximum duty cycle, a discharge current resistor R decrease the maximum duty cycle, a charge current resistor RC is connected from Pin 7 to the Regulator Output. Figure 4 shows an obtainable range of maximum output duty cycle versus the ratio of either R

Figure 18. Maximum Duty Cycle Modification

R

, the oscillator generates an internal blanking

T

is connected from Pin 7 to ground. To

D

or R

C

Current

Regulator Output

1.0

C

R

T

C

D

T

8

6

7

Mirror

I

and C

T

with respect to RT.

D

4 I

Oscillator

2.25 I

Current

Limit Reference

. Resistor R

T

Blanking Pulse

The formula for the charge/discharge current along with the oscillator frequency are given below. The frequency formula is a first order approximation and is accurate for C values greater than 500 pF . For smaller values of CT, refer to Figure 1. Note that resistor RT also programs the Current Limit Comparator threshold.

I

chgńdscg

PWM Comparator and Latch

The pulse width modulator consists of a comparator with the oscillator ramp voltage applied to the non–inverting input,

T

while the error amplifier output is applied into the inverting input. The Oscillator applies a set pulse to the PWM Latch while CT is discharging, and upon reaching the valley voltage, Power Switch conduction is initiated. When C charges to a voltage that exceeds the error amplifier output, the PWM Latch is reset, thus terminating Power Switch conduction for the duration of the oscillator ramp–up period. This PWM Comparator/Latch combination prevents multiple output pulses during a given oscillator clock cycle. The timing diagram shown in Figure 17 illustrates the Power Switch duty cycle behavior versus the Compensation voltage.

Current Limit Comparator and Power Switch

The MC33365 uses cycle–by–cycle current limiting as a means of protecting the output switch transistor from overstress. Each on–cycle is treated as a separate situation. Current limiting is implemented by monitoring the output switch current buildup during conduction, and upon sensing an overcurrent condition, immediately turning off the switch for the duration of the oscillator ramp–up period.

The Power Switch is constructed as a SenseFET allowing a virtually lossless method of monitoring the drain current. It consists of a total of 1462 cells, of which 36 are connected to a 8.1 Ω ground–referenced sense resistor. The Current Sense Comparator detects if the voltage across the sense resistor exceeds the reference level that is present at the inverting input. If exceeded, the comparator quickly resets the PWM Latch, thus protecting the Power Switch. The current limit reference level is generated by the 2.25 I output of the Current Mirror. This current causes a reference voltage to appear across the 405 Ω resistor. This voltage level, as well as the Oscillator charge/discharge current are both set by resistor RT. Therefore when selecting the values for R and CT, RT must be chosen first to set the Power Switch peak drain current, while CT is chosen second to set the desired Oscillator frequency . A graph of the Power Switch peak drain current versus RT is shown in Figure 2 with the related formula below.

+

5.4 R

T

f

I

[

chgńdscg

4C

T

R

– 1.077

PWM

Comparator

8

Ipk+

8.8

MOTOROLA ANALOG IC DEVICE DATA

ǒ

T

1000

Ǔ

MC33365

The Power Switch is designed to directly drive the converter transformer and is capable of switching a maximum of 700 V and 1.0 A. Proper device voltage snubbing and heatsinking are required for reliable operation.

A Leading Edge Blanking circuit was placed in the current sensing signal path. This circuit prevents a premature reset of the PWM Latch. The premature reset is generated each time the Power Switch is driven into conduction. It appears as a narrow voltage spike across the current sense resistor, and is due to the MOSFET gate to source capacitance, transformer interwinding capacitance, and output rectifier recovery time. The Leading Edge Blanking circuit has a dynamic behavior in that it masks the current signal until the Power Switch turn–on transition is completed. The current limit propagation delay time is typically 262 ns. This time is measured from when an overcurrent appears at the Power Switch drain, to the beginning of turn–off.

Error Amplifier

An fully compensated Error Amplifier with access to the inverting input and output is provided for primary side voltage sensing, Figure 16. It features a typical dc voltage gain of 82 dB, and a unity gain bandwidth of 1.0 MHz with 78 degrees of phase margin, Figure 5. The noninverting input is internally biased at 2.6 V ±3.1% and is not pinned out. The Error Amplifier output is pinned out for external loop compensation and as a means for directly driving the PWM Comparator. The output was designed with a limited sink current capability of 270 µA, allowing it to be easily overridden with a pull–up resistor. This is desirable in applications that require secondary side voltage sensing.

Bulk Capacitor Voltage Comparator

The Bulk Capacitor Voltage Comparator is included to sense the brown–out condition of the bulk capacitor line voltage. The non–inverting input, Pin 11, is connected to the voltage divider to sense the line voltage. The inverting input is connected internally to a threshold voltage of 1.25V. As the line voltage drops below 120V (Pin 11 drops below 1.25V), the reset signal is activiated from the PWM Latch to turn off the Power Switch. To prevent erratic switching as the threshold is crossed, hysteresis at Pin 11 is provided.

Undervoltage Lockout

An Undervoltage Lockout comparator has been incorporated to guarantee that the integrated circuit has sufficient voltage to be fully functional before the output stage is enabled. The UVLO comparator monitors the VCC voltage at Pin 3 and when it exceeds 14.5 V, the reset signal is removed from the PWM Latch allowing operation of the Power Switch. T o prevent erratic switching as the threshold is crossed, 5.0 V of hysteresis is provided.

Startup Control

An internal Startup Control circuit with a high voltage enhancement mode MOSFET is included within the MC33365. This circuitry allows for increased converter efficiency by eliminating the external startup resistor, and its associated power dissipation, commonly used in most off–line converters that utilize a UC3842 type of controller. Rectified ac line voltage is applied to the Startup Input, Pin 1. This causes the MOSFET to enhance and supply internal bias as well as charge current to the VCC bypass capacitor that connects from Pin 3 to ground. When VCC reaches the UVLO upper threshold of 15.2 V, the IC commences operation and the startup MOSFET is turned off. Operating bias is now derived from the auxiliary transformer winding, and all of the device power is efficiently converted down from the rectified ac line.

The startup MOSFET will provide a steady current of

1.7 mA, Figure 10, as VCC increases or shorted to ground. The startup MOSFET is rated at a maximum of 400 V with VCC shorted to ground, and 500 V when charging a V capacitor of 1000 µF or less.

Regulator

A low current 6.5 V regulated output is available for biasing the Error Amplifier and any additional control system circuitry. It is capable of up to 10 mA and has short–circuit protection. This output requires an external bypass capacitor of at least 1.0 µF for stability.

Thermal Shutdown and Package

Internal thermal circuitry is provided to protect the Power Switch in the event that the maximum junction temperature is exceeded. When activated, typically at 150°C, the Latch is forced into a ‘reset’ state, disabling the Power Switch. The Latch is allowed to ‘set’ when the Power Switch temperature falls below 140°C. This feature is provided to prevent catastrophic failures from accidental device overheating. It is not intended to be used as a substitute for proper heatsinking.

The MC33365 is contained in a heatsinkable plastic dual–in–line package in which the die is mounted on a special heat tab copper alloy lead frame. This tab consists of the four center ground pins that are specifically designed to improve thermal conduction from the die to the circuit board. Figure 15 shows a simple and effective method of utilizing the printed circuit board medium as a heat dissipater by soldering these pins to an adequate area of copper foil. This permits the use of standard layout and mounting practices while having the ability to halve the junction to air thermal resistance. The examples are for a symmetrical layout on a single–sided board with two ounce per square foot of copper.

CC

MOTOROLA ANALOG IC DEVICE DATA

9

MC33365

OUTLINE DIMENSIONS

P SUFFIX

–A–

R

16 9

–B–

18

P

F

C

S

H

K

G

D

13 PL

M

0.25 (0.010) T

B

PLASTIC PACKAGE

CASE 648E–01

(DIP–16) ISSUE O

L

–T–

SEATING PLANE

S

A

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. DIMENSION L TO CENTER OF LEADS WHEN FORMED PARALLEL.

4. DIMENSION A AND B DOES NOT INCLUDE MOLD PROTRUSION.

5. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.25 (0.010).

M

J

6. ROUNDED CORNER OPTIONAL.

DIM MIN MAX MIN MAX

A 0.740 0.760 18.80 19.30 B 0.245 0.260 6.23 6.60 C 0.145 0.175 3.69 4.44 D 0.015 0.021 0.39 0.53 F 0.050 0.070 1.27 1.77 G 0.100 BSC 2.54 BSC H 0.050 BSC 1.27 BSC J 0.008 0.015 0.21 0.38 K 0.120 0.140 3.05 3.55 L 0.295 0.305 7.50 7.74 M 0 10 0 10

____

P 0.200 BSC 5.08 BSC R 0.300 BSC 7.62 BSC S 0.015 0.035 0.39 0.88

MILLIMETERSINCHES

10

MOTOROLA ANALOG IC DEVICE DATA

MC33365

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty , representation or guarantee regarding the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “T ypical” parameters which may be provided in Motorola data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur. Should Buyer purchase or use Motorola products for any such unintended or unauthorized application, Buyer shall indemnify and hold Motorola and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part. Motorola and are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal Opportunity/Affirmative Action Employer.

MOTOROLA ANALOG IC DEVICE DATA

11

MC33365

How to reach us: USA/EUROPE/Locations Not Listed: Motorola Literature Distribution; JAPAN: Motorola Japan Ltd.; SPD, Strategic Planning Office, 141,

P.O. Box 5405, Denver, Colorado 80217. 1–303–675–2140 or 1–800–441–2447 4–32–1 Nishi–Gotanda, Shinagawa–ku, Tokyo, Japan. 81–3–5487–8488

Customer Focus Center: 1–800–521–6274 Mfax: RMFAX0@email.sps.mot.com – TOUCHTONE 1–602–244–6609 ASIA /PACIFIC: Motorola Semiconductors H.K. Ltd.; Silicon Harbour Centre,

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HOME PAGE: http://motorola.com/sps/

12

– http://sps.motorola.com/mfax/ 852–26629298

◊

MOTOROLA ANALOG IC DEVICE DATA

Mfax is a trademark of Motorola, Inc.

MC33365/D

Datasheet MC33365P Datasheet (MOTOROLA)

Specifications and Main Features

Frequently Asked Questions

User Manual