AD CONVERTER, PHYSICAL QUANTITY DISTRIBUTION DETECTOR AND IMAGING APPARATUS

PROBLEM TO BE SOLVED: To solve the matter of a differential amplifier type comparator that the layout of a differential input section is extremely inefficient when the back gate of a differential pair transistor is connected with the source terminal in order to neglect back bias effect. SOLUTION: A plurality of differential amplifier type comparators for comparing an analog signal obtained from a unit pixel via column signal lines 14-1, 14-2, ..., 14-m with a ramp wave reference voltage Vref are arranged. With reference to the comparison output from these comparators 20(20-1, ..., 20-2, ..., 20-m), the analog signal is converted in the time axis direction and a digital signal is obtained by measuring that time. In such an AD converter, a back gate voltage VrefBG having an AC waveform similar to that of the ramp wave reference voltage Vref is applied to the back gate of differential pair transistors 31 and 32 constituting the comparators 20(20-1, ..., 20-2, ..., 20-m). COPYRIGHT: (C)2007,JPO&INPIT