Correlated double sampler with single amplifier

A circuit for processing a raw sensor output signal from a CCD image sensor to generate an image signal indicative of a sensed image, said circuit including:

• a correlated double sampler having an input node coupled to receive the raw sensor output signal, wherein the correlated double sampler is configured to operate cyclically to process the raw sensor output signal to produce an analog image signal;
• a programmable gain amplifier coupled to receive the analog image signal and configured to produce from the analog image signal an amplified analog image signal;
• and
• analog-to-digital conversion circuitry, coupled to receive the amplified analog image signal and configured to convert a sequence of samples of the amplified analog image signal into the image signal such that said image signal comprises digital data,
• wherein the correlated double sampler includes switch and capacitor circuitry and a first amplifier, wherein the first amplifier has two input terminals and at least one output terminal, the switch and capacitor circuitry comprises switches and capacitors but not an amplifier, the switch and capacitor circuitry is coupled between the input node, the input terminals of the first amplifier, and each said output terminal of the first amplifier, the switch and capacitor circuitry is coupled to receive a first set of control signals followed by a second set of control signals during each cycle of operation of the correlated double sampler, and the switch and capacitor circuitry is configured to operate cyclically during processing of the raw sensor output signal such that a portion of the analog image signal produced at said at least one output terminal in response to the first set of control signals is indicative of the value of one pixel of the image and a subsequent portion of the analog image signal produced at said at least one output terminal in response to the second set of control signals is indicative of the value of a next pixel of the image.

A correlated double sampler circuit which operates cyclically to process a raw sensor output signal from an image sensor to generate an image signal indicative of a sensed image, said circuit including:

• an input node coupled to receive the raw sensor output signal;
• a first amplifier having two input terminals and two output terminals;
• and
• switch and capacitor circuitry comprising switches and capacitors but not an amplifier, wherein the switch and capacitor circuitry is coupled between the input node, the input terminals of the first amplifier, and the output terminals of the first amplifier, the switch and capacitor circuitry is coupled to receive a first set of control signals followed by a second set of control signals during each cycle of operation of the correlated double sampler circuit, and the switch and capacitor circuitry is configured to operate cyclically during processing of the raw sensor output signal such that a portion of the image signal generated in response to the first set of control signals is indicative of the value of one pixel of the image and a subsequent portion of the image signal generated in response to the second set of control signals is indicative of the value of a next pixel of the image.

A circuit for processing a raw sensor output signal from an image sensor to generate an image signal indicative of a sensed image, said circuit including:

• a correlated double sampler having an input node coupled to receive the raw sensor output signal, wherein the correlated double sampler is configured to operate cyclically to process the raw sensor output signal to produce an analog image signal;
• a programmable gain amplifier coupled to receive the analog image signal and configured to produce from the analog image signal an amplified analog image signal;
• and
• analog-to-digital conversion circuitry, coupled to receive the amplified analog image signal and configured to convert a sequence of samples of the amplified analog image signal into the image signal such that said image signal comprises digital data,
• wherein the correlated double sampler includes switch and capacitor circuitry and a first amplifier, wherein the first amplifier has two input terminals and at least one output terminal, the switch and capacitor circuitry comprises switches and capacitors but not an amplifier, the switch and capacitor circuitry is coupled between the input node, the input terminals of the first amplifier, and each said output terminal of the first amplifier, the switch and capacitor circuitry is coupled to receive a first set of control signals followed by a second set of control signals during each cycle of operation of the correlated double sampler, and the switch and capacitor circuitry is configured to operate cyclically during processing of the raw sensor output signal such that a portion of the analog image signal produced at said at least one output terminal in response to the first set of control signals is indicative of the value of one pixel of the image and a subsequent portion of the analog image signal produced at said at least one output terminal in response to the second set of control signals is indicative of the value of a next pixel of the image.