一种用于大功率音频功放的高稳定性LDO

A high stability LDO for high power audio amplifier

设计了一种用于大功率音频功放的高稳定性低压差线性稳压器(LDO),对其电路结构和工作原理进行了分析,重点讨论了上电预充模块、环路稳定性及电源抑制能力。采用0.18μm1P4M BCDMOS工艺,不同工艺角下,Cadence Spectre仿真表明,LDO的温度系数小于47.45 ppm/℃,瞬态响应最大变化量为50 mV,电源抑制大于71 dB@1 kHz,工作电压范围5 V-24 V,输出电压值为3.3 V;tt(渡越时间)模型下,工作电压为18 V时,对大功率音频功放进行系统仿真,LDO表现出约为30μs的启动时间,其输出电压值能很好地跟踪负载电流的变化。

A high stability Low Dropout Linear Regulator（LDO） is designed for high power audio amplifier. The structure and operational principle are analyzed, and the charging circuit, the stability of the loop and the power supply rejection are described in detail. The circuit is implemented in 0.18 μm 1P4M BCDMOS technology. Based on various corner models, Cadence Spectre simulation results show that the maximum temperature coefficient of the LDO circuit is 47.45 ppm/℃, the maximum overshoot of output voltage of 50 mV, the minimum Power Supply Rejection（PSR） of 71 dB@1 kHz, the operating voltage of 5 V-24 V, and the output voltage of the LDO of 3.3 V. Based on tt（transit time） models and the operating voltage of 18 V, the simulation results of the high power audio amplifier show that the output voltage of the LDO circuit comes to steady state within 30 μs and can track the load current changes of the LDO.