Fingerprint detection circuit and fingerprint recognition system

A fingerprint identification system, which transmits a first signal to a finger, the fingerprint identification system comprising:

• a plurality of fingerprint detecting circuits, each fingerprint detecting circuit comprising:
• a conductive layer, configured to couple a touch from the finger;
• and
• an amplifier, comprising:
• a first input terminal, coupled to the conductive layer;
• a second input terminal, configured to receive a second signal;
• and
• an output terminal, wherein a first capacitance is formed between the output terminal and the first input terminal;
• wherein a first phase of the first signal is inverse to a second phase of the second signal;
• a fingerprint determining module, coupled to the plurality of fingerprint detecting circuits, configured to determine whether each fingerprint detecting circuit corresponds to a finger ridge or a finger valley.

A fingerprint detecting circuit, comprising:

• a conductive layer;
• and
• an amplifier, comprising a first input terminal, a second input terminal and an output terminal;
• wherein the first input terminal is coupled to the conductive layer, and a first capacitance is formed between the first input terminal and the output terminal;
• the conductive layer is configured for forming a second capacitance with a finger, and the second capacitance is configured to couple a first signal transmitted to the finger to the first input terminal;
• the second input terminal is configured to receiving a second signal which has a phase inverse to that of the first signal.