Linear LTC4222热插拔两路控制方案

Linear公司的LTC4222是两路热插拔控制器,采用外接的N沟通过MOSFET,板电源电流和浪涌电流能以可调整的速率慢慢增加.板内的10位ADC和I2C接口允许监视每路的电流,电压和故障状态.工作电压从2.9V到29V,可用在板卡的插拔,电路中断器,计算机,服务器和平台管理.本文介绍了LTC4222的主要特性,方框图, 典型应用以及两种案例应用电路图.

The LTC4222 Hot Swap controller allows two power paths to be safely inserted and removed from a live backplane. Using external N-channel pass transistors, board supply voltages and inrush currents are ramped up at an adjustable rate. An I2C interface and onboard ADC allows for monitoring of current, voltage and fault status for each channel.

The device features adjustable, analog, foldback current limit circuits and a Soft-Start circuit that sets the dI/dt of the inrush currents. An I2C interface may confi gure the part to latch off or automatically restart after the LTC4222 detects a fault on either channel.

The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card and power-up either
automatically upon insertion or wait for an I2C command to turn on.

LTC4222主要特性:
Allows Safe Insertion Into a Live Backplane
10-Bit ADC Monitors Currents and Voltages
I2C/SMBus Interface
Wide Operating Voltage Range: 2.9V to 29V
dI/dt Controlled Soft-Start
High Side Drive for External N-Channel MOSFETs
No External Gate Capacitors Required
Input Overvoltage/Undervoltage Protection
Optional Latchoff or Auto-Retry After Faults
Alert Host After Faults
Inrush Current Limit with Foldback
Available in 32-Pin (5mmx5mm) QFN and 36-Pin SSOP Packages

LTC4222应用:
Live Board Insertion
Electronic Circuit Breakers
Computers, Servers
Platform Management



图1.LTC4222典型应用



图2.LTC4222功能方框图



图3.LTC4222应用电路图(1)



图4.LTC4222应用电路图(2)(3.3V和12V应用,顺序打开光学绝缘I2C通信,5A限流,当12V空缺时,肖特基二极管打开3.3V开关)