Patent ID: 7511652
Filing Date: 2009-03-31
Classification: H03K,H03M

Abstract:
1. A comparison device with calibration, comprising: a first comparator, having a first input terminal, a second input terminal, and an output terminal generating a first comparison result; a chop switching unit, transmitting a first signal and a second signal to the first input terminal and the second input terminal of the first comparator respectively during a first period, and transmitting the first signal and the second signal to the second input terminal and the first input terminal of the first comparator respectively during a second period, wherein the chop switching unit switches the operation states of the first period and the second period according to a control signal; a first compensation unit, coupled between the chop switching unit and the first input terminal of the first comparator for compensating a third signal outputted from the chop switching unit to the first terminal of the first comparator according to a first digital control code and a step-size; and a delta-sigma modulation unit, calculating a differential code between the first comparison result and a second comparison result with the awareness of the operation states of the chop switch unit, and generating the first digital control code and the second digital control code; a second comparator, having a first input terminal receiving a compensated signal, a second input terminal receiving the second signal, and an output terminal generating the second comparison result; and a second compensation unit, coupled between the delta-sigma modulation unit and the first input terminal of the second comparator for compensating the first signal according to the second digital control code and the step-size, and generating the compensated signal.