CMOS Power Management Unit Along with Load Regulation Using Switched Capacitor Converters

Abstract

In this paper, a power management unit (PMU) with battery backup and output load regulation using switched capacitor converters using 0.18 m Complimentary Metal Oxide Semiconductor technology is presented. Low power consumption is obtained by employing subthreshold design methods. The main building blocks of the PMU are a voltage regulator, a voltage monitor, a battery backup and switched capacitor (SC) converters. The voltage regulator has an output voltage VOUT at 0.95 V and 0.968 V at input voltages of 0.98 V and 1.33 V, respectively. Perpetual operation at the load side is confirmed by implementing a battery backup module, which provides the battery voltage to the load circuit when the output voltage of the energy harvesting (EH) source is insufficient. The presented PMU consumes 46 nW at 0.98 V and 3.919 W with SC converters at 1.33 V. Different voltages can be tapped from the PMU from the 3:2, 2:1, 3:1, 4:1 and 5:1 down converters that provide output voltages of 0.67 V, 0.5 V, 0.33 V, 0.25 V and 0.2 V to the load, respectively. The maximum current that can be delivered by the PMU is 1 mA at an input voltage of 1.33 V and is adequate for many low power applications.