Design of High PSR and Low Quiescent Current Low-Dropout Linear Regulator
A low-dropout linear regulator with high power supply rejection(PSR)and low quiescent current was designed using a 0.18 μm BCD process.A detailed analysis was conducted on the effects of multiple power ripple propagation paths on the PSR of the system.A three-stage error amplifier with a dual-rail power supply was designed to optimize the PSR at low-middle frequency.Additionally,a pre-regulator was introduced to reduce the influence of the voltage reference module on the low-frequency PSR of the system.An ultra-low quiescent current-voltage reference based on the depletion transistor was designed to lower the quiescent current of the system.Simulation results demonstrate that the quiescent current can be as low as 5 μA at different output voltages,and within a load current range of 250 mA,the PSR is below-110 dB at 1 kHz and below-55 dB at 1 MHz.
low-dropout linear regulator(LDO)power supply rejection(PSR)pre-regulatorlow quiescent current
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