TOP242-249
Section List
Functional Block Diagram ......................................................................................................................................... 3
Pin Functional Description........................................................................................................................................ 4
TOPSwitch-GX Family Functional Description ........................................................................................................ 5
CONTROL (C) Pin Operation ................................................................................................................................. 6
Oscillator and Switching Frequency ....................................................................................................................... 6
Pulse Width Modulator and Maximum Duty Cycle ................................................................................................. 7
Light Load Frequency Reduction............................................................................................................................ 7
Error Amplifier ......................................................................................................................................................... 7
On-chip Current Limit with External Programmability ............................................................................................. 7
Line Under-Voltage Detection (UV) ........................................................................................................................ 8
Line Overvoltage Shutdown (OV) ........................................................................................................................... 8
Line Feed Forward with DCMAX Reduction .............................................................................................................. 8
Remote ON/OFF and Synchronization ................................................................................................................... 9
Soft-Start ................................................................................................................................................................ 9
Shutdown/Auto-Restart .......................................................................................................................................... 9
Hysteretic Over-Temperature Protection ................................................................................................................ 9
Bandgap Reference................................................................................................................................................ 9
High-Voltage Bias Current Source........................................................................................................................ 10
Using Feature Pins.................................................................................................................................................... 11
FREQUENCY (F) Pin Operation........................................................................................................................... 11
LINE-SENSE (L) Pin Operation ............................................................................................................................ 11
EXTERNAL CURRENT LIMIT (X) Pin Operation ................................................................................................. 11
MULTI-FUNCTION (M) Pin Operation .................................................................................................................. 12
Typical Uses of FREQUENCY (F) Pin ...................................................................................................................... 15
Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins....................................................... 16
Typical Uses of MULTI-FUNCTION (M) Pin ............................................................................................................. 19
Application Examples ............................................................................................................................................... 21
A High Efficiency, 30 W, Universal Input Power Supply........................................................................................ 21
A High Efficiency, Enclosed, 70 W, Universal Adapter Supply.............................................................................. 22
A High Efficiency, 250 W, 250 - 380 VDC Input Power Supply ............................................................................. 23
Multiple Output, 60 W, 185 - 265 VAC Input Power Supply.................................................................................. 24
Processor Controlled Supply Turn On/Off ............................................................................................................ 25
Key Application Considerations .............................................................................................................................. 27
TOPSwitch-II vs. TOPSwitch-GX.......................................................................................................................... 27
TOPSwitch-FX vs. TOPSwitch-GX ....................................................................................................................... 28
TOPSwitch-GX Design Considerations ................................................................................................................ 29
TOPSwitch-GX Layout Considerations................................................................................................................. 31
Quick Design Checklist......................................................................................................................................... 31
Design Tools ......................................................................................................................................................... 33
Product Specifications and Test Conditions .......................................................................................................... 34
Typical Performance Characteristics ...................................................................................................................... 41
Part Ordering Information ........................................................................................................................................ 45
Package Outlines ...................................................................................................................................................... 45
E
7/01
August 8, 2000
2
POWERINT [ Power Integrations ]
