Patent ID: 6734908
Filing Date: 2004-05-11
Classification: H04N

Abstract:
A correlated double sampling circuit comprising:an input changeover switch that has one input terminal connected to a signal line and the other input terminal receiving a fixed potential and selects and outputs either a signal of the signal line or the fixed potential; a first clamping means having a clamping capacitor that has one terminal on an input side connected to an output terminal of the input changeover switch and a clamping switch that has one terminal connected to the other terminal on an output side of the clamping capacitor and the other terminal to which a clamping potential is applied; a first sample hold means having a sample hold switch that has one terminal connected to the terminal of the output side of the clamping capacitor and a sample hold capacitor that has one terminal connected to the other terminal of the sample hold switch; and a control means for controlling the input changeover switch, the clamping switch and the sample hold switch so as to switch the input changeover switch to the signal line side in a first period, clamp the signal of the signal line in a first half of the first period by the first clamping means, thereafter sample and hold a signal on the output side of the clamping capacitor in the latter half of the first period by the first sample hold means, switch the input changeover switch to the fixed potential side in a second period subsequent to the first period, sample and hold the clamping potential on the output side of the clamping capacitor by the first clamping means with respect to the fixed potential in the first half of the second period and thereafter sample and hold a signal on the output side of the clamping capacitor by the first sample hold means.