Patent ID: 7408392
Filing Date: 2008-08-05
Classification: H03K

Abstract:
1. A converter circuit for converting a pulse-width modulated input signal into a voltage output signal, comprising: a reference current source of a first polarity; a reference current source of a second, opposite polarity; a switch array controlled in response to the pulse-width modulated input signal; and a pair of channels, each with an operational amplifier that has differential inputs and differential outputs, a first capacitor in each channel connected for providing a negative feedback from a first output to a first input, and a second capacitor in each channel connected for providing a negative feedback from a second output to a second input; wherein each channel of the pair is configured and adapted to be conditioned by the switch array to be selectively operated in an integration mode, a sampling mode or a reset mode; so that, for each channel, in the integration mode, the switch array selectively connects the reference current source of first polarity either to the first or to the second input of the operational amplifier, and connects the reference current source of second polarity to the other of the first and second inputs; in the sampling mode, the switch array selectively disconnects the reference current sources of first and second polarity, and the outputs of the operational amplifier provide the voltage output signal; and, in the reset mode, the switch array selectively disconnects the reference current sources of first and second polarity and short-circuits the first and second capacitors.