A Power-Efficient LDO with Slew-Rate-Enhanced Amplifier and Buffer for Biomedical Applications with High-Frequency Load Transient

In this paper, a low-power, fast-transient and low dropout regulator (LDO) is proposed for high-frequency load transient in biomimetic electrical stimulation medical devices. The implementation of a dynamic recycling folded cascode (DRFC) amplifier alone with a dynamic rail-to-rail adaptive buffer (DRAB) reduces power transistor’s dimension and enhances the transient performance. The LDO is implemented with 55 nm CMOS process. With an output capacitor of $2.2 \mu \mathrm{~F}$ and under the load step between 0 and 150 mA, post-simulation results show that the undershoot and overshoot of high-frequency load transient ($10 \mu \mathrm{~s}$ heavy/light load duration) is 43 mV and 35 mV, respectively. The proposed regulator consumes $5.1 \mu \mathrm{~A}$ quiescent current, achieving 99.97% equivalent current efficiency at 150 mA load current.