Silicon Laboratories Inc.

Erik Pankratz

Axel Thomsen

Kenneth Wilson Fernald

Dazhi Wei

Jinwen Xiao

Praveen Kallam

Gang Yuan

Arnab Dutta

Imranul Islam

A POR circuit for a secondary supply domain of an IC. A bias and reference circuit provides startup current and a reference voltage for a comparator. The comparator compares the reference voltage with a primary supply voltage and develops a bias current. The bias and reference circuit and the comparator includes a VGS loop which mirrors the bias current to develop the reference voltage. When the comparator switches, the bias current is at the low quiescent current level. A level shift and isolation circuit initially isolates a primary POR signal from the secondary domain. When the comparator switches, the primary POR signal is detected and level shifted to control the reset state. The delay circuit senses ramping of the secondary supply voltage and provides a delayed secondary POR signal a predetermined time period after the secondary supply voltage achieves a predetermined voltage threshold to additionally control the reset state.

Power-on reset system for secondary supply domain

In one embodiment, an apparatus includes a controller to control a voltage regulator. The controller may have a first comparator circuit to compare a first reference voltage to a feedback voltage. In turn, the first comparator circuit may include: a first comparator having a first input terminal to receive the feedback voltage and a second input terminal to receive the reference voltage and an output node to output an error signal based on the comparison; and a first pre-charge circuit coupled between the first input terminal and the output node configured to pre-charge a first portion of a compensation network to a pre-charge level. The first controller may further include a second comparator circuit coupled to the first comparator circuit compare the error signal to a ramp signal and to generate a first control output to control a power train of the voltage regulator in a first mode of operation.

Pre-charge technique for a voltage regulator

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Austin, TX, United States of America

Erik Pankratz