Abstract: A fast signal response circuit with hysteresis control includes a switch element and a comparator. The switch element includes a first and a second input terminals and a control terminal, the first terminal is configured to receive a first reference signal, the second terminal is configured to receive a second reference signal, the control terminal is configured to receive a control signal, and the switch element is configured to output the first or the second reference signal through a first output terminal according to the control signal. The comparator includes a third input terminal, a fourth input terminal and a second output terminal, the third input terminal is connected to the first output terminal, the fourth input terminal is configured to receive a sensing signal corresponding to a light input, and the second output terminal is connected to the controller and is configured to output the comparison result.