一种基于密勒倍增的高性能LDO的设计

Design of a High Performance LDO Based on Miller Capacitor Multiplier

基于零极点跟踪技术,提出一种新的LDO频率补偿架构。利用密勒电容倍增原理和零极点跟踪技术,在很小的补偿电容面积下使LDO获得全负载范围内的环路稳定。摆率增强电路的应用使系统具有优越的负载瞬态调整性能。基于0.5μm标准CMOS工艺,对LDO进行仿真验证。结果表明,系统空载下,静态电流为32μA,且能提供最大200 mA的负载电流;在输出电容为2.2μF、负载电流以200 mA/10 ns突变时,最大下冲电压仅为10 mV,没有明显的上冲。

A new frequency compensation topology for LDO was presented based on pole-zero tracking.By using Miller capacitor multiplier and pole-zero tracking,the LDO circuit was kept stable in full range of load conditions with only a small area for compensation capacitor.Excellent performance of load transient regulation was achieved for the system by using SR enhancement circuit.LDO with the proposed technology was simulated based on 0.5 μm standard CMOS process.Simulation results showed that the proposed circuit dissipated 32 μA of quiescent current with empty load and it was capable of delivering load current up to 200 mA.For an output capacitance of 2.2 μF and with a load step of 200 mA /10 ns,the circuit had a maximum undershoot voltage of only 10 mV and no remarkable overshoot.