zoukankan      html  css  js  c++  java
  • External components provide true shutdown for boost converter

    The step-up switching-converter circuit in Figure 1 presents a familiar problem: If you shut down boost converter IC1 by pulling its  input low, external inductor L1 and forward-biased Schottky diode D1 allow the load to continue drawing current. For battery-powered applications that present a heavy load—300 mA, for example—this unwanted dc-current path may quickly drain the battery. Adding an N-channel MOSFET, Q1, and a 100-kΩ resistor, R1, solves the problem by opening the unwanted current path during shutdown. The resulting circuit is suitable for battery-powered-system applications in which a microcontroller handles the power management.

    Asserting a low logic level on the  input simultaneously shuts down the switching converter, a MAX756, and turns off the MOSFET, thereby blocking load current by removing the load's ground connection. When the  signal deasserts, the 100-kΩ pullup resistor turns on the MOSFET by pulling the MOSFET's gate high. With its ground reconnected, the load then draws current from the activated boost-converter circuit.

    For optimum results at high load currents, select a logic-level MOSFET for Q1 that presents a reasonably low on-resistance. The MOSFET's drain-to-source breakdown voltage should also be able to withstand at least twice the maximum output voltage you expect from the boost converter. If necessary, you can reduce the MOSFET's effective on-resistance by connecting two or more MOSFETs in parallel.

  • 相关阅读:
    是河南大学的悲哀???
    装完manjaro先要卸载
    技术博客
    VIM从入门到中级教程
    HTTP中GET与POST的区别
    AngularJS 拦截器实现全局$http请求loading效果
    angular指令监听ng-repeat渲染完成后执行自定义事件方法
    icheck如何修改样式大小
    Sublime text3 代码格式化插件
    代理模式小试
  • 原文地址:https://www.cnblogs.com/shangdawei/p/4128132.html
Copyright © 2011-2022 走看看