US 11,838,665 B2
Comparator, ad converter, photoelectric conversion device, imaging system, and movable object
Hideo Kobayashi, Tokyo (JP); and So Hasegawa, Kanagawa (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Feb. 16, 2021, as Appl. No. 17/176,395.
Claims priority of application No. 2020-030600 (JP), filed on Feb. 26, 2020.
Prior Publication US 2021/0266485 A1, Aug. 26, 2021
Int. Cl. H04N 25/75 (2023.01); H03K 5/24 (2006.01); H03M 1/06 (2006.01)
CPC H04N 25/75 (2023.01) [H03K 5/2481 (2013.01); H03M 1/0607 (2013.01)] 30 Claims
OG exemplary drawing
 
1. A comparator comprising:
a comparison circuit that performs comparison between an input signal and a reference signal and changes a level of a signal to be output to a first node in accordance with a result of the comparison; and
a positive feedback circuit including an amplifier unit that includes a current source load and outputs a signal in accordance with a potential of the first node to a second node, and a feedback unit that positively feeds back a signal in accordance with a potential of the second node to the first node,
wherein the feedback unit includes a first transistor to which output of the amplifier unit is fed back and a switch that controls turning on or off of the first transistor, and
wherein the amplifier unit of the positive feedback circuit includes a second transistor of a first conductivity type whose first main node is connected to a first voltage node supplied with a first voltage and whose control node is connected to the first node and a first current source load connected between a second voltage node supplied with a second voltage, which is different from the first voltage, and a second main node of the second transistor.