Chapter 6 - Power Management Integrated Circuits

Abstract

This chapter focuses on power management integrated circuits. The proliferation of power management functions in the typical mobile phone, and the volumes associated with each phone model, argues for customization and ASIC integration. While the need to manipulate voltages and currents are contrary to the use of fine geometry complementary metal-oxide-semiconductor (CMOS) and integration with the digital baseband or applications processor, PMICs with many voltage regulators on one chip can be constructed with bipolar CMOS and CMOS technologies. From a regulator perspective, power management integrated circuits (PMICs) generally offer one to three types of programmable regulators—LDO, buck, and boost—which convert battery voltage to a stable voltage for a particular component. LDOs with integrated pass field effect transistors (FETs) is are cost-effective, simple to use, and only need a filtering capacitor on the output. However, these conveniences come at the expense of efficiency. For advanced systems such as 3G WCDMA phones, PMICs offer multiple buck regulators to support independent high-efficiency zoning of multiple processors (core, baseband, application, etc.), memory, and/or high power peripherals. Programmable buck regulators are critical to further optimize power consumption through DVS, an increasingly important feature in advanced processors, which dynamically adjust their clock frequency and voltage, to reduce power consumption when the processor is not 100% utilized.