Frequency Stop-Band Management System for DC-DC Converters

Ever complex electronic systems have pushed the requirements on power management to new limits, with applications needing to satisfy stringent operating frequency constraints while maintaining high efficiency. This article addresses the requirement to avoid any operation of a DC-DC converter in specific frequency bands when regulating light loads in discontinuous-conduction-mode (DCM) and operating in pulse-skip-mode (PSM). The presented stop-band-management-system (SBMS) is a versatile mixed-signal solution that has been designed for an inverting buck-boost (IBB) converter, which generates a programmable output voltage in the range of -1V to -9V from a Li-Ion battery. Targeting consumer Active-Matrix-Organic-Light-Emitting-Diode (AMOLED) display applications, a power-management-integrated-circuit (PMIC) has been fabricated in a 180nm bipolar-CMOS-DMOS (BCD) process, and the effectiveness of the proposed solution is shown with experimental results.