A Reconfigurable Hybrid Low Dropout Voltage Regulator for Wide-Range Power Supply Noise Rejection and Energy-Efficiency Trade-Off

A scan-reconfigurable hybrid low dropout (LDO) macro with four operating modes to support tuning across a wide range of power supply noise rejection and power efficiency is presented. The configurations include: 1) a full-digital LDO; 2) an analog loop in parallel with a digital loop in switched mode control; 3) an analog LDO in parallel with discrete current sources; and 4) discrete current sources with an analog LDO in shunt with the load. Measurements on a 130-nm CMOS test chip show a wide power supply noise rejection range of -9 dB to -34 dB and a corresponding power efficiency range of 87% to 56%.