一种低功耗快速瞬态响应无片外电容LDOOA北大核心CSTPCD

In order to solve the problem of transient response of LDO without off-chip capacitance,an N-type power FET LDO based on Miller BICMOS OTA structure was proposed.As the intermediate stage of the circuit,BJT Push-Pull has the characteristics of low power consumption,high gain and high slew rate.The output disturbance was coupled to the intermediate stage through the capacitor,a fast feedback loop was formed,the bandwidth of the feedback loop was expanded and the load transient response speed was improved.Because the output stage is a source follower and the overall system is a two-stage op amp structure,good stability can be achieved just through the compensation of the Miller capacitor.The circuit was designed based on the Hynix 180 nm BCD process.The simulation results show that the quiescent current of the system is about 10 μA,the gain is about 102 dB,the bandwidth is about 800 kHz,and the phase margin is about 61°.The feedback loop bandwidth is about 30 MHz.When the input voltage is 5 V,no external capacitor is connected,the load capacitance is 5 pF,and the output current switches from 20 mA to 200 μA in 300 ps,the system response time is about 420 ps,and the overshoot voltage is about 253 mV.