Chopper die comparator null for serial-parallel die AD converter

摘要

PURPOSE:To realize a comparator with a stable hold function by providing 1st capacitor, driving 3rd switch in phase with the 1st switch, holding a signal potential and comparing it with a reference potential. CONSTITUTION:A switch 2 is subject to ON/OFF control so that it is turned on depending on a phase of a clock signal phis, e.g., at a high potential, and switches 8, 12 are subject to ON/OFF control in phase with the switch 2. Moreover, the switch 4 is subject to ON/OFF control so that it is turned on depending on the phase of a clock signal phir, e.g., at a high potential. When the switches 2, 8, 12 are turned on at a period of the high signal phis, a signal potential Vs is fed to the circuit, and capacitors 6, 9 are charged. When the signals phis, phir are at a low potential, the switches 2, 4, 8, 12 are all turned on the charging potential of the capacitors 6, 9 is held and when the signal phir reaches a high potential, the switch 4 is turned on, the potential Vs and the reference potential Vr are compared and an output is extracted from the terminal 14.