Rev. B 03/10

2

TOP264-271

www.powerint.com

Section List

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

Pin Functional Description ...................................................................................................................................... 3

TOP264-271 Functional Description ........................................................................................................................ 4

CONTROL (C) Pin Operation.................................................................................................................................... 5

Oscillator and Switching Frequency.......................................................................................................................... 5

Pulse Width Modulator ............................................................................................................................................ 5

Maximum Duty Cycle ............................................................................................................................................... 6

Error Amplifier .......................................................................................................................................................... 6

On-Chip Current Limit with External Programmability ............................................................................................... 6

Line Undervoltage Detection (UV)............................................................................................................................. 6

Line Overvoltage Shutdown (OV).............................................................................................................................. 7

Hysteretic or Latching Output Overvoltage Protection (OVP)..................................................................................... 7

Line Feed-Forward with DC

Remote ON/OFF ..................................................................................................................................................... 8

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

Shutdown/Auto-Restart (for OCP, SCP, OPP)......................................................................................................... 10

Hysteretic Over-Temperature Protection (OTP) ....................................................................................................... 10

Bandgap Reference ............................................................................................................................................... 10

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

Typical Uses of FREQUENCY (F) Pin ...................................................................................................................... 12

Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins .......................................... 13

Application Examples .............................................................................................................................................. 15

Low No-load, High Efficiency, 65 W, Universal Input Adapter Power Supply

..................................................................... 15

Very low No-load, High Efficiency, 30 W, Universal Input, Open Frame, Power Supply .............................................................. 17

Key Application Considerations .............................................................................................................................. 18

TOPSwitch-JX vs.TOPSwitch-HX

........................................................................................................................ . 18

TOP264-271 Design Considerations ..................................................................................................................... 18

TOP264-271 Layout Considerations ...................................................................................................................... 20

Quick Design Checklist .......................................................................................................................................... 21

Design Tools .......................................................................................................................................................... 21

Product Specifications and Test Conditions .......................................................................................................... 23

Typical Performance Characteristics .................................................................................................................... 30

Package Outlines .................................................................................................................................................... 34

Part Ordering Information ........................................................................................................................................ 35