Patent ID: 8203779

Claim:
A readout circuit for an image sensor, comprising: at least one column amplifier (CA), which generates a CA reset signal when the column amplifier is reset; a capacitor and a switch configured to receive signal from column of the image sensor; a multiplexer coupled between (a) the capacitor and the switch and (b) an input of the column amplifier; a correlated double sampling (CDS) circuit for controllably receiving an output of the column amplifier, wherein the CDS circuit comprises; a sample-and-hold-reset signal (SHR) switch for sampling the CA reset signal: a SHR capacitor coupled to the SHR switch for holding the CA reset signal; a sample-and-hold-image signal (SHS) switch for sampling an image signal of the image sensor; a SHS capacitor coupled to the SHS switch for holding the image signal; and a switch network coupled between the CDS circuit and another amplifier other than the CA amplifier, wherein the switch network is configured such that outputs of the CDS circuit are controllably sent in sequence to the another amplifier.