US Patent 7271432 Image-sensing apparatus

In a solid-state image-sensing device, when image sensing is performed, in each pixel, MOS transistors T1 and T5 are turned on and a MOS transistor T6 is turned off so that a MOS transistor T2 operates in a subthreshold region. When resetting is preformed, in each pixel, the MOS transistors T1 and T5 are turned off and the MOS transistor T6 is turned on so that the gate voltage of the MOS transistor T2 is kept constant. In this state, the MOS transistor T2 is brought first into a conducting state and then, by turning a signal φVPS to a high level, into a cut-off state. This permits a signal proportional to the threshold value of the MOS transistor T2 to be output as compensation data.