Comparator implementation for processing signals output from an image sensor

摘要

An image sensor includes an analog-to-digital converter receiving a pixel signal output. The converter includes a first inverting amplifier circuit having an input and an output, the first inverting amplifier circuit including a first bias circuit having a control node and configured to source current for first inverting amplifier circuit operation. The converter further includes a second inverting amplifier circuit having an input and an output, the second inverting amplifier circuit including a second bias circuit having a control node and configured to source current for second inverting amplifier circuit operation. The output of the first inverting amplifier circuit is coupled to the input of the second inverting amplifier circuit. A positive feedback circuit couples the output of the second inverting amplifier circuit to the control node of the first bias circuit.

主权项

1. An image sensor, comprising:
an array of pixels; a first analog to digital converter (ADC) including a first inverting amplification stage and a second inverting amplification stage, wherein an output of the first inverting amplification stage is coupled to an input of the second inverting amplification stage; a bias line for the first inverting amplification stage of the first ADC; and a positive feedback coupling between an output of the second inverting amplification stage of the first ADC and the bias line.