Capacitance measurement circuit and capacitance measurement method thereof
First Claim
1. A capacitance measurement circuit for measuring a capacitor under test, the capacitance measurement circuit comprising:
- a capacitance to time unit for generating a first clock signal and a second clock signal reverse to the first clock signal according to a first charge time of the capacitor under test and a second charge time of a variable capacitor;
a continuous time integrator for receiving the first clock signal and outputting an integral signal according to the first clock signal; and
an analog to digital converter for outputting a digital signal corresponding to a capacitance difference between the capacitor under test and the variable capacitor according to the integral signal when the number of clocks of the second clock signal is equal to a default value.
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Abstract
A capacitance measurement circuit and a capacitance measurement method thereof. The capacitance measurement circuit for measuring a capacitor under test includes a capacitance to time unit, a continuous time integrator and an analog to digital converter. The capacitance to time unit generates a first clock signal and a second clock signal reverse to the first clock signal according to a first charge time of the capacitor under test and a second charge time of a variable capacitor. The continuous time integrator receives the first clock signal and outputs an integral signal according to the first clock signal. When the number of clocks of the second clock signal is equal to a default value, the analog to digital converter outputs a digital signal corresponding to a capacitance difference between the capacitor under test and the variable capacitor according to the integral signal.
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Citations
15 Claims
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1. A capacitance measurement circuit for measuring a capacitor under test, the capacitance measurement circuit comprising:
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a capacitance to time unit for generating a first clock signal and a second clock signal reverse to the first clock signal according to a first charge time of the capacitor under test and a second charge time of a variable capacitor; a continuous time integrator for receiving the first clock signal and outputting an integral signal according to the first clock signal; and an analog to digital converter for outputting a digital signal corresponding to a capacitance difference between the capacitor under test and the variable capacitor according to the integral signal when the number of clocks of the second clock signal is equal to a default value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A capacitance measurement method for measuring a capacitor under test, the capacitance measurement method comprising the steps of:
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(a) setting an integral signal, outputted from a continuous time integrator, to be equal to an initial voltage; (b) generating a first clock signal and a second clock signal reverse to each other according to a first charge time of the capacitor under test and a second charge time of a variable capacitor; (c) outputting the first clock signal to the continuous time integrator and outputting the integral signal according to the first clock signal; and (d) outputting a digital signal corresponding to a capacitance difference between the capacitor under test and the variable capacitor according to the integral signal when the number of clocks of the second clock signal is equal to a default value. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification