1. An apparatus, comprising: a plurality of switches; and a controller coupled to the plurality of switches to configure the plurality of switches to: couple a first terminal of a sensing capacitor to a first supply voltage and couple a second terminal of the sensing capacitor to a second supply voltage to charge the sensing capacitor; couple the first terminal of the sensing capacitor to a first terminal of a second capacitor and couple the second terminal of the sensing capacitor and a second terminal of the second capacitor to the second supply voltage to transfer charge between the sensing capacitor and the second capacitor; couple the first and second terminals of the sensing capacitor to the second supply voltage to discharge the sensing capacitor; and couple the first terminal of the sensing capacitor to the second terminal of the second capacitor, couple the first terminal of the second capacitor to the first supply voltage, and couple the second terminal of the sensing capacitor to the second supply voltage to reverse couple the sensing capacitor to the second capacitor.