ST VIPER26LD 基于VIPER26LD隔离反激式AC－DC电源参考设计方案
ST公司的VIPER26LD是一款具有最高达800V电源的雪崩强度，一个PWM控制器，用户自定义过流限制，防止反馈网络断开，滞后的温度保护，软启动和故障安全自重启功能的离线转换器。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及PCB元件布局图。
The device is an off-line converter with an 800 V avalanche ruggedness power section, a PWM controller, user defined overcurrent limit, protection against feedback network disconnection, hysteretic thermal protection, soft start up and safe auto restart after any fault condition.
Advance frequency jittering reduces EMI filter cost. Burst mode operation and the devices very low consumption both help to meet the standard set by energy saving regulations.
VIPER26LD主要特性：
■ 800 V avalanche rugged power section
■ PWM operation with frequency jittering for low EMI
■ Operating frequency:
– 60 kHz for L type
– 115 kHz for H type
■ Standby power < 50 mW at 265 VAC
■ Limiting current with adjustable set point
■ On-board soft-start
■ Safe auto-restart after a fault condition
■ Hysteretic thermal shutdown
VIPER26LD应用：
■ Auxiliary power supply for appliances
■ Power metering
■ LED drivers
■ SMPS for set-top boxes, DVD players and recorders
