PROGRAMMABLE BAND-PASS FILTER CIRCUIT OF ANALOG FRONT-END USED FOR CAPACITANCE DETECTION

摘要

A programmable band-pass filter circuit, which is included by an analog front-end circuit and used for capacitance detection, includes an operational amplifier, an input resistor, a feedback resistor, and a feedback capacitor. The operational amplifier includes a first input coupled to a reference level, a second input, and an output. The input resistor has a first end coupled to a sensed capacitor and a second end coupled to the second input of the operational amplifier. The feedback resistor and feedback capacitor are connected between the second input of the operational amplifier and the output of the operational amplifier, respectively.

主权项

1. A programmable band-pass filter circuit included by an analog front-end circuit and used for capacitance detection, comprises:
an operational amplifier, having a first input, a second input, and an output, the first input being coupled to a reference level; an input resistor, having a first end coupled to a sensed capacitor and a second end coupled to the second input of the operational amplifier; a feedback resistor, coupled between the second input of the operational amplifier and the output of the operational amplifier; and a feedback capacitor, coupled between the second input of the operational amplifier and the output of the operational amplifier.