A fingerprint sensor is disclosed. The fingerprint sensor includes a sensor plate, a voltage source, a control circuit and a first conductive plate. The sensor plate detects a first capacitance in response to a touch event on the fingerprint sensor. The voltage source establishes a predetermined voltage difference between a first node and a second node. The control circuit, connected to the sensor plate via the first node, charges a first capacitor associated with the first capacitance during a charge period, and discharges the first capacitor during a discharge period. The first conductive plate, separated from the sensor plate, is coupled with the voltage source via the second node. During the charge period and the discharge period of the control circuit, a voltage difference between the sensor plate and the first conductive plate is maintained at the predetermined voltage difference.