Capacitance measurement circuit and method
First Claim
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1. A capacitance measuring method for measuring a capacitance of an under-test capacitor, the measuring method comprising:
- pre-charging a storage capacitor;
performing a charge transfer between the under-test capacitor and the storage capacitor;
charging and discharging the storage capacitor, includingdischarging the storage capacitor when a voltage of the storage capacitor is higher than a reference voltage, andcharging the storage capacitor when the voltage of the storage capacitor is lower than the reference voltage; and
measuring the capacitance of the under-test capacitor according to the voltage of the storage capacitor.
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Abstract
A capacitance measurement circuit and method are provided. A storage capacitor is pre-charged. Charge transfer is performed between an under-test capacitor and the storage capacitor. The storage capacitor is discharged and charged according to a relationship between a voltage of the storage capacitor and a reference voltage. The capacitance of the under-test capacitor is measured according to the voltage on the storage capacitor.
48 Citations
22 Claims
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1. A capacitance measuring method for measuring a capacitance of an under-test capacitor, the measuring method comprising:
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pre-charging a storage capacitor; performing a charge transfer between the under-test capacitor and the storage capacitor; charging and discharging the storage capacitor, including discharging the storage capacitor when a voltage of the storage capacitor is higher than a reference voltage, and charging the storage capacitor when the voltage of the storage capacitor is lower than the reference voltage; and measuring the capacitance of the under-test capacitor according to the voltage of the storage capacitor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A capacitance measurement circuit for measuring a capacitance of an under-test capacitor, comprising:
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a storage capacitor; a switch circuit coupled to the storage capacitor, a reference voltage and a voltage source; a voltage detector coupled to the storage capacitor for detecting a voltage of the storage capacitor; a switch controller coupled to the voltage detector and the switch circuit for controlling the switch circuit; and a current source coupled to the switch circuit; wherein, under control of the switch controller, the reference voltage is coupled to the storage capacitor through the switch circuit to pre-charge the storage capacitor; the under-test capacitor is coupled to the storage capacitor and the voltage source for performing charge transfer between the under-test capacitor and the storage capacitor; discharging the storage capacitor by the current source when the voltage of the storage capacitor is higher than the reference voltage; and charging the storage capacitor by the under-test capacitor by charge transfer according to a relationship between when the voltage of the storage capacitor is lower than the reference voltage. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification