Image sensors for advanced driver assistance systems utilizing regulator voltage verification circuitry to detect malfunctions

Abstract

A regulator voltage verification circuit for an Advanced Driver Assistance System (ADAS) enables testing of voltage regulators in a pixel array. The circuit generates test voltages representing expected black and white pixel values as a function of the regulator's output voltage. The test voltages are selectively passed to an analog-to-digital conversion circuit in a test mode, while pixel outputs are processed in normal mode. A voltage divider connected to the regulator output creates upper and lower test voltages, which are selected by a multiplexer. The test voltages are routed through a digital correlated double sampling switch to a comparator and ripple counter, converting the analog test values to digital data. By comparing the digital output to expected values, the system can detect regulator malfunctions and issue appropriate warnings. The circuit can be implemented across multiple rows of a pixel array, with test results optionally averaged for accuracy.