CAPACITANCE DETECTING SENSORS AND RELATED DEVICES AND SYSTEMS

摘要

Capacitance detecting circuit is disclosed for fingerprint sensing and other applications. The capacitance detecting circuit includes a first capacitor, an integrator, a second capacitor, a comparator, and a counter. The integrator can generate an integrating output voltage and includes a first single-ended amplifier and at least one integration capacitor. The first single-ended amplifier includes a first input terminal and an integrating output terminal. The comparator can generate a comparing output and include a negative input terminal coupled to the integrating output terminal of the first single-ended amplifier, a positive input terminal to receive a reference voltage, and a comparing output terminal to output the comparing output voltage. The counter is coupled to the comparing output terminal and can generate a counter output. A connection between the second capacitor and the first input terminal is controlled to be conducted or cutoff according to the comparing output.

主权项

1. A capacitance detecting circuit, comprising:
a pixel sensing circuit that includes a sensing conducting layer that interfaces with an object to form a capacitance with the object; a first capacitor coupled to the pixel sensing circuit; an integrator electrically coupled to the first capacitor and configured to generate an integrating output voltage, the integrator including:
a first single-ended amplifier, including:
an integrating output terminal configured to output the integrating output voltage, anda first input terminal coupled to the first capacitor, andat least one integration capacitor coupled to the first input terminal; and a comparator coupled to the integrating output terminal of the first single-ended amplifier and configured to generate a comparing output voltage indicative of the capacitance between the sensing conducting layer and the object.