Patent ID: 9612266
Date: 2017-04-04
CPC Classifications: G01D,G01R,H03M

Claim:
1. A capacity measuring circuit comprising: a measuring voltage source configured to feed a sinusoidal voltage signal to a first terminal of a capacity to be measured so as to cause a temporal change in a charge stored on the capacity to be measured; and a delta-sigma modulator, the delta-sigma modulator being configured to receive a charge from a second terminal of the capacity to be measured and to provide a digital output signal which depends on a quantity of the charge received from the capacity to be measured; wherein the capacity measuring circuit is configured to bring the capacity to be measured to a first charge state in a first phase using the sinusoidal voltage signal and to bring the capacity to be measured to a second charge state in a second phase using the sinusoidal voltage signal; and wherein the delta-sigma modulator is configured to receive an amount of charge equaling a difference between an amount of charge stored on the capacity to be measured in the first charge state and an amount of charge stored on the capacity to be measured in the second charge state and to provide the digital output signal in dependence on the amount of charge received.