Patent ID: 7977979

Claim:
A high-speed multi-stage voltage comparator, comprising: a multi-stage amplifier having a plurality of preamplifiers cascaded on multiple stages; a latch connected to an output terminal of the multi-stage amplifier; a plurality of capacitors storing voltages output from the respective preamplifiers; a plurality of offset-cancellation switches, each offset-cancellation switch being connected between a common node and a second end of a corresponding capacitor among the plurality of capacitors, to eliminate offset from outputs of the respective preamplifiers; and a plurality of reset switches, each reset switch being connected between the common node and a first end of a corresponding capacitor among the plurality of capacitors, to reset the outputs of the respective preamplifiers, wherein the reset switches reset the outputs of the respective preamplifiers in response to respective clocks maintaining an active state until after input voltages input to the respective preamplifiers are crossed.