Patent ID: 8319527

Claim:
An apparatus for voltage sampling, comprising: an analog to digital converter (ADC) configured to sample an input voltage, where the ADC comprises: a first switch having a first terminal of the first switch connected to the input voltage, a second switch having a first terminal of the second switch coupled to a second terminal of the first switch, a first capacitor having a first terminal of the first capacitor coupled to the first terminal of the second switch and a second terminal of the first capacitor coupled to a first voltage, the first capacitor being configured to provide a pre-charge voltage, substantially equal to the input voltage, at the second terminal of the first switch before the first switch is turned on; and a filter having an output coupled to a second terminal of the second switch, and a digital to analog converter (DAC) having an output coupled to an input of the filter and an input coupled to an output of a quantizer, where the quantizer generates the output of the quantizer based on an input coupled to the first terminal of the first capacitor.