一种LDO极零点跟踪的频率补偿电路设计

针对LDO线性稳压器的稳定性问题，文章在分析传统LIX）频率补偿方法的基础上，提出了一种新颖的跟踪负载电流变化的动态频率补偿方法，相对于传统依靠输出电容ESR产生零点的频率补偿方式，该电路的频率补偿是在环路内部产生一个零点进行补偿，并给出其具体的电路实现。在SMICCMOS0．35μm工艺下的仿真结果表明，从0～100mA，整个系统相位裕度都均在65°以上，且负载瞬态过冲小于50mV，这与传统的LDO频率补偿方法相比，明显的提高了LDO的频率稳定性和瞬态响应。

A Pole-Zero Tracking Frequency Compensation for LDO Regulator

Based on analysis of traditional frequency compensation method of low dropout regulator （LDO）, a novel frequency compensation structure and its circuit implementation is presented to solve the problem of stability for LDO. Compared with the frequency compensation method relying on the zero generated by the ESR of the output capacitance, the proposed topology generates a zero internally for stability. The proposed scheme is implemented using SMIC 0. 35μm digital CMOS process and the simulation results indicate that the phase margin of the loop is above 65 degree and the overshoot of transient response is less 50mV for the load current being from 0mA to 100mA. Comparing with conventional frequency compensation methods, the proposed design indicate an improved frequency stability and better transient response.