the max1864 power-supply controller is designed for cost-effective applications such as cable modem consumer premise equipment (cpe), xdsl cpe and set-top boxes. it includes a current mode synchronized step-down controller and two positive regulator gain blocks.
this chip does not have a power-on-reset (por) function. this application note demonstrates how to add this function, using one of the linear regulator controllers to reset the microprocessor 140ms after the output voltage is within the regulated output voltage.
figure 1 shows the circuit schematic. por is used to monitor the main output, vout1. when the main output, vout1, reaches its specified output voltage, por becomes active-high with 140ms delay. the synchronized buck and one positive regulator gain block (b2 and fb2) controller in the max1864 provide two outputs, while the second regulator gain block (b3 and fb3) monitors the main output voltage. a resistor, r6, is connected between the output, vout1 and fb3, and a capacitor, c6, is connected from the fb3 pin to ground. a pull-up resistor, r5, is connected to the supply voltage (+5v) through b3, and the output from b3 can be used as the por output. when the output, vout1, is within the regulated range, the voltage at the fb3 pin gradually increases by charging the capacitor, c6, through the output, vout1. the voltage across c6 is dependent on the time constant of r6 and c6. with the values shown for r6 and c6, por will become high 140ms after the time where the voltage at the fb3 pin is high enough.
figure 1. two output with por function.
figure 2 shows the por and vout1 waveforms.
figure 2. experimental waveforms.
示波器真的是调试模拟电源最好工具?
ZEISS蔡司工业CT技术原理及其运用
VR/AR职位热门 企业市场需求旺盛
浅谈以太网变压器
我的PCB打样之旅:从失望到惊喜的一站式服务体验
Adding POR Function to the MAX
FPGA校企人才对接会参会企业邀请函
如何判断MOS管的工作状态
英伟达公司第二季度的收入轻松超过了预期
紫光展锐推出面向大众市场的5G移动平台T750
《肿瘤免疫治疗领域初创公司调研》
华为首款65吋电视或由京东方代工 推动4K、8K高质量内容
FPGA的原型介绍
无线跑步蓝牙耳机哪个牌子好,百元挂脖式蓝牙耳机推荐
5种让机器人提高业务性能的方法
国产OLED屏幕正在崛起 维信诺公开表示公司产品已进入一线品牌客户供应链
iPhone8、诺基亚8最新消息汇总:iPhone8与诺基亚8在外观、性能、续航、配色、发布时间、价格上谁是全场mvp?
高压气动三通球阀的适用领域和使用优势的介绍
零部件出口管控严厉 华为FPGA库存即将见底的消息传出
区块链中的节点和主节点的作用是什么