Fairchild FSQ500L 5.1V/400mA紧凑型省电模式反激式设计

Fairchild公司的FSQ500L主要为替代线性供电电源而设计的低价格产品。芯片集成SenseFET的电流模式PWM，内建PWM控制器主要有以下特性：内置振荡器、欠压锁定保护、过载保护、内置前沿消隐电路、优化的门驱动开/关、磁滞热关断保护和温度补偿精密电流源。本文主要介绍FSQ500L的主要特性及器件框图，同时介绍一款基于FSQ500L芯片的2.04W输出的供电电源开发方案。主要介绍方案的主要特性、性能、方案原理图、方案PCB图及方案器件列表。

The FSQ500L is specially designed for a replacement of linear power supplies with low cost. This device combines current-mode Pulse Width Modulator (PWM) with a senseFET. The integrated PWM controller features include: a fixed oscillator, Under Voltage Lockout (UVLO) protection, Overload Protection (OLP), Leading-Edge Blanking (LEB), an optimized gate turn-on/turn-off driver, Thermal Shutdown (TSD) protection with hysteresis, and temperature-compensated precision-current sources for loop compensation. When compared to a linear power supply, the FSQ500L device reduces total size and weight, while increasing efficiency, productivity, and system reliability. This device provides a basic platform for cost-effective flyback converters.

FSQ500L主要特性：

Single Chip 700V SenseFET Power Switch

Precision Fixed Operating Frequency: 130kHz

No-load consumption 250mW at 265V_ACwith Burst Mode and Down to 60mW with External Bias

Internal Startup Switch

Soft-Start Time Tuned by External Capacitor

Under-Voltage Lockout (UVLO) with Hysteresis

Pulse-by-Pulse Current Limit

Overload Protection (OLP) and Internal Thermal Shutdown Function (TSD) with Hysteresis

Auto-Restart Mode

No Need for Auxiliary Bias Winding

FSQ500L应用：

· DVD

· STB

· Video Game Console

· Consumer Applicance


图1. FSQ500L内部方框图

FEBFSQ500L_H257v1主要特性：

Single-Chip700V SenseFET Power Switch

Precious Fixed Operation Frequency:130kHz

No-load consumption 250mW at 256VAC with Burst Mode and Down to 60mW with External Bias

Internal startup Swith

Soft-Start Time Tuned by External Capacitor

Under-Voltage Lockout with Hysteresis

Pulse-by-Pulse Current limit

Overload Protection and Internal Thermal Shutdown Function with Hysteresis

Auto-Restart Mode

No Need for Auxiliary Bias Winding

FEBFSQ500L_H257v1电路图：


图2. FEBFSQ500L_H257v1电路图