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LDO具有高的纹波抑制和低噪声特点,在低输入输出压差以及RF领域应用广泛。在负载电流变化范围大的情况下,动态补偿成为必然选择。基于CSMC 0.5μm CMOS工艺,设计了一种利用MOS栅源电容实现动态补偿的LDO。采用反偏二极管模拟了寄生阱电容对系统稳定性的影响,并提出减小系统带宽、优化系统稳定性的方案。为了实现快速动态响应,设计前馈电容优化了系统。实验表明,设计的电路具有高PSRR和快速响应能力,适用于便携式设备供电。
LDO has a high ripple rejection and low noise characteristics, in the low input and output voltage and RF field widely used. In the case of large load current changes, dynamic compensation becomes the inevitable choice. Based on the CSMC 0.5μm CMOS process, an LDO with dynamic compensation of gate-source capacitance of MOS is designed. The influence of the parasitic well capacitance on the stability of the system is simulated with a reverse-biased diode. Proposals are made to reduce the system bandwidth and optimize the system stability. In order to achieve fast dynamic response, the feedforward capacitor is designed to optimize the system. Experiments show that the circuit design has high PSRR and fast response capability, suitable for portable device power supply.