Image-sensing-system booster circuit for driving image sensor

摘要

In a drive circuit of a solid-state imaging device, no specific voltage source exclusively used to set a substrate voltage is required. An external circuit required when the entire drive circuit is fabricated as an integrated circuit can be eliminated. An image sensing system has a solid-state imaging device formed on a semiconductor body. The solid-state imaging device includes a plurality of photo sensors formed in a major surface of the semiconductor body. The photo sensors receive light incident thereon and generate charges corresponding to the incident light and accumulating the charges therein. A video signal output outputs a video signal corresponding to the accumulated charges, and a charge drain discharges charges from the photo sensors. A timing generator generates a timing signal. A first power supply source provides a first voltage to the solid-state imaging device. A second power supply source provides a second voltage to the solid-state imaging device. The second voltage is higher than the first voltage, and a driver for the solid-state imaging device includes a driving circuit for driving the video signal output in response to the timing signal. A booster circuit receives the first and second voltages and provides a third voltage higher than the second voltage. The booster circuit is driven in synchronism with the timing signal, and a voltage setter sets a drive voltage of the charge drain based on the third voltage.