Ramp generator for low noise image sensor

摘要

A readout circuit for use in an image sensor includes a sense amplifier circuit coupled to a bitline to sense analog image data from a pixel cell of the image sensor. An analog to digital converter is coupled to the sense amplifier circuit to convert the analog image data to digital image data. A ramp generator circuit is coupled to generate a first ramp signal. The analog to digital converter is coupled to generate the digital image data in response to the analog image data and the first ramp signal. A first capacitive voltage divider is coupled to the ramp generator. The first capacitive voltage divider is coupled to reduce an output voltage swing of the first ramp signal coupled to be received by the analog to digital converter to reduce noise in the first ramp signal.

主权项

1. A readout circuit for use in an image sensor, comprising:
a sense amplifier circuit coupled to a bitline to sense analog image data from a pixel cell of the image sensor; an analog to digital converter coupled to the sense amplifier circuit to convert the analog image data to digital image data; a ramp generator circuit coupled to generate a first ramp signal, wherein the analog to digital converter is coupled to generate the digital image data in response to the analog image data and the first ramp signal; and a first capacitive voltage divider coupled to the ramp generator, wherein the first capacitive voltage divider is coupled to reduce an output voltage swing of the first ramp signal coupled to be received by the analog to digital converter to reduce noise in the first ramp signal.