Low Power Management Unit with Load Regulation using DC-DC Switched Capacitor Converters in 0.18μm CMOS

Abstract

A power management unit (PMU) with battery extender and output load regulation is presented using 0.18$\mu$m CMOS technology. For designing few sub-circuits of the PMU, subthreshold region of MOSFET is utilized, which significantly contributes to achieve low power operation. The proposed PMU consists of a voltage regulator, a voltage monitor, a battery backup module and two DC-DC Switched Capacitor (SC) Converters. The regulator output voltage V OUT is regulated at 0.95 V and 0.968 V at input voltages of 0.98 V and 1.33 V respectively. To ensure continuous operation at the load circuit, a battery extender module is implemented in case of unavailability of EH source. The power consumption of the PMU at input voltages of 0.98 V and 1.33 V is 46nW and 1.567 $\mu$W respectively. Near threshold operation is ensured at the load side by further regulating the voltage at the output to 0.67 V and 0.5 V using 3:2 and 2:1 SC Converters respectively. The current consumption of the 3:2 and 2:1 SC Converters is 748 nA and 751 nA respectively. The proposed PMU can deliver output current up to 1 mA at 1.33 V of input voltage and is suitable for numerous applications where low power operation is essential as it consumes a small amount of power.