一种快速瞬态响应的无片外电容LDO

A Capacitor-Less LDO with Fast Transient Response

设计了一种快速瞬态响应的无片外电容低压差线性稳压器（LDO）。采用具有摆率增强作用的缓冲级电路,可以在不额外增加静态电流的同时检测输出端电压,在负载瞬间变化时增大功率器件栅极电容的充放电电流。缓冲级电路还引入了简单的负反馈技术,增加了环路的相位裕度。采用SMIC 180nm的CMOS工艺进行设计和仿真。仿真结果表明,当输入电压为1.4-5V时,该LDO的输出电压为1.2V,最大负载电流为300mA;负载电流在1mA和300mA间变化时,最大过冲电压为76.5mV,响应时间仅为1.5μs。

A capacitor-less low-dropout linear regulator （LDO） with fast transient response was designed. A slew rate enhancement buffer was adopted to detect the output voltage without additional quiescent current, and the charging and discharging current of gate capacitance of the power devices was increased when the load varied instantaneously. A simple negative feedback technique was introduced in the buffer stage to increase the phase margin of the loop. The circuit was designed and simulated under SMIC 180 nm CMOS process. Simulation results showed that the LDO＇s output voltage was 1.2 V, the maximum load current was 300 mA under 1.4-5 V input voltage. As the load current varied between 1 mA and 300 mA, the circuit could response within 1.5 9s, and the maximum overshoot voltage was 76.5 mV.