TOP252-262
Section List
Functional Block Diagram
....................................................................................................................................... 4
Pin Functional Description
...................................................................................................................................... 6
TOPSwitch-HX Family Functional Description
....................................................................................................... 7
CONTROL (C) Pin Operation .................................................................................................................................... 8
Oscillator and Switching Frequency.......................................................................................................................... 8
Pulse Width Modulator ............................................................................................................................................ 9
Maximum Load Cycle .............................................................................................................................................. 9
Error Amplifier .......................................................................................................................................................... 9
On-Chip Current Limit with External Programmability ............................................................................................... 9
Line Under-Voltage Detection (UV).......................................................................................................................... 10
Line Overvoltage Shutdown (OV) ............................................................................................................................ 11
Hysteretic or Latching Output Overvoltage Protection (OVP)................................................................................... 11
Line Feed-Forward with DC
MAX
Reduction .............................................................................................................. 13
Remote ON/OFF and Synchronization.................................................................................................................... 13
Soft-Start ............................................................................................................................................................... 13
Shutdown/Auto-Restart ......................................................................................................................................... 13
Hysteretic Over-Temperature Protection ................................................................................................................. 13
Bandgap Reference ............................................................................................................................................... 13
High-Voltage Bias Current Source .......................................................................................................................... 13
Typical Uses of FREQUENCY (F) Pin
...................................................................................................................... 15
Typical Uses of VOLTAGE MONITOR (V) and EXTERNAL CURRENT LIMIT (X) Pins
.......................................... 16
Typical Uses of MULTI-FUNCTION (M) Pin
........................................................................................................... 18
Application Examples
.............................................................................................................................................. 21
A High Efficiency, 35 W, Dual Output – Universal Input Power Supply ..................................................................... 21
A High Efficiency, 1500 W, 250-380 VDC Input Power Supply ................................................................................ 22
A High Efficiency, 20 W Continuous – 80 W Peak, Universal Input Power Supply ................................................... 23
A High Efficiency, 65 W, Universal Input Power Supply ........................................................................................... 24
Key Application Considerations
.............................................................................................................................. 25
TOPSwitch-HX vs.TOPSwitch-GX
.......................................................................................................................
. 25
TOPSwitch-HX Design Considerations .................................................................................................................. 26
TOPSwitch-HX Layout Considerations ................................................................................................................... 27
Quick Design Checklist .......................................................................................................................................... 31
Design Tools .......................................................................................................................................................... 31
Product Specifications and Test Conditions
.......................................................................................................... 32
Typical Performance Characteristics
.................................................................................................................... 39
Package Outlines
.................................................................................................................................................... 43
Part Ordering Information
........................................................................................................................................ 47
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Rev. F 01/09
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