Integrated tracking voltage regulation and control for pmuic to prevent latch-up or excessive leakage current

Abstract

A tracking and control method and circuit for use in a power management unit integrated circuit (PMUIC) that enables multiple voltage regulator outputs to maintain a same voltage or a ratiometric relation to a reference voltage source. When the reference voltage source is powered down or falls below a prescribed level, the tracking power supplies are automatically switched to their internal bandgap reference voltage. Accordingly, outputs of the tracking power supplies are prevented from introducing large transient excursions that might result in malfunctions in the circuitry of the load such as latch-ups. Ratiometric tracking further provides coordinated preservation of logic interface levels, and reduces leakage current.