Light-Powered Starter for Micro-Power Boost DC–DC Converter for CMOS Image Sensors

Abstract

The design of a starter for a low-voltage, micro-power boost DC-DC converter intended for powering CMOS image sensors is presented. A unique feature of the starter is extremely low current, below 1 nA, supplying its control circuit. Therefore, a high-voltage (1.3 V) configuration of series-connected photovoltaic diodes available in a standard CMOS process or a small external LED working in photovoltaic mode can be used as an auxiliary supply for the control circuit. With this auxiliary supply, the starter can generate a starting voltage from 1 to 2.7 V using 50-200 mV supply voltage. The starter was verified by simulations and measurements of a prototype chip fabricated in a standard 180-nm CMOS technology. The results of simulations and tests showed correct operation of the starter in the temperature from 0 to 50°C and under process parameters variation.