Self-calibration circuit and method for capacitors
AssigneeProlific Technology Inc.
InventorsKuo-Jen Kuo, Kang-Shou Chang, Yu-Lung Hung
Life of this patent
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Abstract
A self-calibration circuit and method for capacitors are provided. A capacitor array is calibrated to approximate a reference capacitor according to an average parameter generated by calibrating the capacitor array multiple times. Since the capacitance of the compensation capacitor required to be connected to the target capacitor in parallel is determined according to the average parameter generated by performing the calibration multiple times, the error caused by a single calibration can be reduced, and meanwhile the calibration error caused by a reference voltage error or noise is reduced.
Claims9
A self-calibration circuit for capacitors, comprising:
- a reference capacitor, coupled between a common terminal and a first input terminal;
- a capacitor array, comprising:
- a target capacitor, coupled between the common terminal and a second input terminal;
- and
- a plurality of compensation capacitors, one ends of the compensation capacitors being coupled to the common terminal, and other ends of the compensation capacitors being coupled to a first switch set, wherein the first switch set has a plurality of first switches respectively coupled between the compensation capacitors and the second input terminal;
- a calibration circuit, coupled to the reference capacitor and the capacitor array, and the calibration circuit comparing capacitances of the reference capacitor and the capacitor array to generate a parameter for determining conducting states of the first switches of the first switch set, so as to adjust a parallel connection relation between the compensation capacitors and the target capacitor for calibrating the capacitance of the capacitor array;
- a counting unit, coupled to the calibration circuit and the first switch set, for temporarily store the parameters corresponding to the conducting states of the first switches,
- wherein the calibration circuit repeatedly compares the capacitances of the reference capacitor and the capacitor array to generate a plurality of parameters, and the counting unit accumulates the parameters and calculates an average of the parameters to output a final parameter, so as to determine the conducting states of the first switches of the first switch set for calibrating the capacitance of the capacitor array.
A self-calibration method for capacitors, for calibrating a capacitor array, so that a capacitance of the capacitor array approximates to a capacitance of a reference capacitor, the capacitor array comprising a target capacitor and a plurality of compensation capacitors, and the method comprising:
- (a) comparing capacitances of the capacitor array and the reference capacitor to output a parameter;
- (b) adjusting a parallel connection relation between the compensation capacitors and the target capacitor according to the parameter, so as to calibrate the capacitance of the capacitor array;
- (c) repeating the steps (a) and (b) to generate a plurality of parameters;
- (d) accumulating the parameters and calculating an average of the parameters to output a final parameter;
- and
- (e) determining the parallel connection relation between the compensation capacitors and the target capacitor according to the final parameter.
Dependencies are inferred from the claim text.