A Bandgap Diode-Based Voltage Band Detection Circuit With Fast Response Time and Low Vmin on Intel 4 Logic Technology

Abstract

A fast, accurate, single-rail voltage detection circuit (VDC) is presented. Low voltage operation is achieved by a variable gain Charge Pump (CP) followed by a Low-Dropout regulator (LDO). An Open-loop band gap reference (BGREF), passed to a dynamic comparator, achieves an undervoltage trip point of 0.62 V with 8.7 mV sigma, and an overvoltage trip point of 1.22 V with 12 mV sigma, demonstrated on Intel 4 silicon prototype. The design operates without any filter cap, allowing a fast, power-on ramp of $2~\mu $ s, and brown-out detection of <200 ns. A voltage band detection of 0.48–1.22 V is enabled through a finite-state machine (FSM) to modify CP and LDO gain depending on input voltage.