摘要
芯片设计中,为了降低芯片功耗,会将芯片划分为多个电源域.在芯片进入低功耗模式时,将不工作的电源域掉电,仅保留必须的电源域带电,达到降低芯片功耗的目的.芯片进入低功耗模式后,主机要和芯片通信,需要先将芯片退出低功耗模式,然后才能正常通信.12C作为主机和芯片间常用的通信的接口,是一种常用的芯片退低功耗模式唤醒源.常用的I2C唤醒电路中,采用同步电路方式,需要额外的一个高频时钟,用来采样SDA和SCL信号,识别到I2C的起始信号后,唤醒芯片.这种同步唤醒电路,高频采样时钟在低功耗模式期间需要一直工作,增加了唤醒电路的功耗,同时由于只检测START信号,会存在误唤醒的情况.本文介绍了一种I2C异步唤醒电路,该电路不需要高频时钟,也可避免误唤醒的发生.
Abstract
In chip design,in order to reduce power consumption,the chip will be divided into multiple power domains.When the chip enters low-power mode,the inactive power domains will be powered off,and only the necessary power domain is powered on,which can make power consumption as low as possible.Once enters low-power mode,the chip must exit low-power mode before it can communicate normally.12C,as a commonly used communication interface,is a commonly used chip wake-up source for low-power mode.In a common I2C wake-up circuit,a synchronous circuit is used,which requires an additional high-frequency clock to sample SDA and SCL signals.The chip will be waked up once detecting START symbol.This synchronous wake-up circuit requires the high-frequency sampling clock to operate continuously during low-power mode,which increases the power consumption of the wake-up circuit.At the same time,due to only detecting the START symbol,there may be false wake-up situations.This article introduces an I2C asynchronous wake-up circuit that does not require a high-frequency clock and can avoid the occurrence of false wake-up.
维普
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