This document is a design guide of FSQ-series Fairchild Power Switch (FPS™) released by Fairchild Semiconductor Corporation.
The document introduces the FSQ-series Fairchild Power Switch (FPS), an integrated PWM controller and Sense FET designed for quasi-resonant off-line Switch Mode Power Supplies. It explains how this topology reduces electromagnetic interference and increases efficiency compared to conventional hard-switched converters by utilizing valley switching in discontinuous conduction mode.
| Switching Frequency Range (DCM) | 55kHz to 67kHz |
|---|---|
| Blanking Time (tB) | 15μs |
| Detection Time Window (tW) | 3μs |
The document suggests setting an estimated efficiency of 0.7 to 0.75.
The recommendation is to select a DC link capacitor of 2-3µF per watt.