A Capacitor-Less Ripple-Less Hybrid LDO With Exponential Ratio Array and 4000x Load Current Range

A hybrid low-dropout regulator (LDO) with exponential-ratio array (ERA) and analog based transient voltage compensation is implemented in 65-nm CMOS. The hybrid LDO (HLDO) is capable of reducing a voltage drop upon load change by more than 70%, and the ERA enables fast tracking time, enlarging dynamic range of the digital loop. The HLDO achieves 99.7% current efficiency with the output dynamic range of 0.01-to-40 mA (4000x) and obtains the transient output voltage drop of 55 mV for a load current jump of 0.55 mA from 20 mu A. When both the dynamic and the static performances are considered, the proposed HLDO shows the state-of-the-art performance among other recent digital LDOs and HLDOs.