AN-6075 Datasheet, PDF (1/11 Pages) Fairchild Semiconductor – Compact Green-Mode Adapter

www.fairchildsemi.com
AN-6075
Compact Green-Mode Adapter Using FSQ500L for Low Cost
1. Introduction
This application note describes a detailed design strategy for
a compact flyback converter. Design considerations and
mathematical equations are presented, as well as guidelines
for a printed circuit board layout. The FSQ500L is designed
for a replacement of linear power supplies to achieve low
cost. This device combines current-mode Pulse Width
Modulator (PWM) with a single-chip 700V senseFET. The
integrated PWM controller features include: fixed operating
frequency (130KHz), under-voltage lockout (UVLO)
protection, soft-start time tuned by external capacitor,
overload protection (OLP), leading-edge blanking (LEB),
optimized gate turn-on/turn-off driver, thermal shutdown
(TSD) protection with hysteresis, and temperature-
compensated precision-current sources for loop
compensation. The no-load power consumption can be less
than 250mW without auxiliary bias winding and down to
60mW with auxiliary bias winding for universal AC input
voltage range to meet the power conservation requirements.
When compared to a linear power supply, the FSQ500L
reduces total size and weight, while increasing efficiency,
productivity, and system reliability. This device provides a
platform for cost-effective flyback converters.
Figure 1. SOT-223 Pin Configuration
Figure 2. Typical Application
© 2008 Fairchild Semiconductor Corporation
Rev. 1.0.0 • 9/11/08
www.fairchildsemi.com