一种带保护电路的低功耗LDO

为了保护芯片不受电源电压起伏的影响,设计了一种应用于移动多媒体广播(CMMB)的带保护电路的低功耗低压降线性调节器(LDO);为了保证LDO的反馈环路在所有负载电流下均稳定,采用低增益、低输出阻抗的buffer来驱动输出管,使环路的相位裕度都高于40°;为了避免输出管在过流和过热时损坏,设计了过流保护电路和过热保护电路:过流保护电路将过载的电流限制在150 mA;过热保护电路包含滞回功能,在温度高于145℃时,过热保护电路将LDO关断,当温度低于125℃时,LDO重新打开。LDO的输入电压范围为1.5～3.3 V,输出电压为1.2 V。LDO采用0.35μm CMOS工艺设计,共消耗30μA的静态电流,最大负载电流为80 mA。芯片面积为380.2μm×198μm。

A Low Power Low Dropout Regulator with Protection Circuits

This paper presents a low power low dropout regulator(LDO) with protection circuits which shield a chip from fluctuations in supply rails for CMMB application.By employing a low gain low output impedance buffer to drive the gate node of the pass device,phase margin with over 40° is achieved under any load current conditions.To avoid destroy the pass device by the over current and over temperature,the over current protection(OCP) circuit which limits the maximum load current at 150 mA,and the over temperature protection(OTP) circuit which turns off the LDO when the temperature is higher than 145℃,and turns on the LDO when the temperature is lower than 125℃ are designed.The input voltage range is 1.5~3.3 V,and the output voltage is 1.2 V.The LDO with protection circuits has been implemented in a 0.35 μm CMOS process.It dissipates only 30 μA quiescent current at no load condition and is able to deliver up to 80 mA maximum load current.The chip area of the LDO is 380.2 μm×198 μm.