Patent ID: 11886666
Assignee: HIMAX TECHNOLOGIES LIMITED
Field: Basic communication processes (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 12:
13. A detection circuit adaptable to a fingerprint detection system, the detection circuit comprising:
an integrating amplifier coupled to receive a photo-detected voltage from a sensor panel and configured to generate time integral of the photo-detected voltage, thereby resulting in a time-integral signal;
an analog-to-digital converter (ADC) that converts the time-integral signal into a digital form;
a first coupling capacitor with a first plate connected to receive the first common-mode voltage and a second plate electrically coupled to a non-inverting input node of the integrating amplifier;
wherein a first common-mode voltage of the sensor panel is coupled to the integrating amplifier to prevent noise occurred in the first common-mode voltage from affecting the time-integral signal;
a buffer amplifier that provides a reset voltage;
a detection switch; and
a second coupling capacitor with a first plate connected to receive the first common-mode voltage and a second plate electrically coupled to a non-inverting input node of the buffer amplifier via the detection switch.