CAPACITANCE EVALUATION CIRCUIT AND ELECTRONIC DEVICE USING THE SAME
First Claim
1. A capacitance evaluation circuit, comprising:
- a capacitive voltage divider comprising a switch circuit, a first capacitor and a second capacitor, wherein the switch circuit is coupled to the first and second capacitors, the switch circuit is controlled by a first clock signal and a second clock signal, which is an inversion signal of the first clock signal, and a voltage variation of a first terminal of the first capacitor is coupled to a first terminal of the second capacitor based on a conduction state of the switch circuit;
an analog-to-digital converter (ADC), coupled to the capacitive voltage divider, converting a voltage of the first terminal of the second capacitor into a first digital signal; and
a processing module, coupled to the ADC, detecting a capacitance of the second capacitor and a capacitance variation of the second capacitor according to the first digital signal of the ADC and a parameter of the ADC.
1 Assignment
0 Petitions
Accused Products
Abstract
A capacitance evaluation circuit includes a capacitive voltage divider, an analog-to-digital converter (ADC) and a processing module. The capacitive voltage divider includes a switch circuit, a known capacitor and a capacitor under test. The switch circuit is controlled by first and second clock signals. A voltage variation at a first terminal of the known capacitor is coupled to a first terminal of the capacitor under test based on a conduction state of the switch circuit. The ADC converts a voltage on the first terminal of the capacitor under test into a digital signal. The processing module detects a capacitance and a capacitance variation of the capacitor under test according to the digital signal from the ADC and a parameter of the ADC.
-
Citations
7 Claims
-
1. A capacitance evaluation circuit, comprising:
-
a capacitive voltage divider comprising a switch circuit, a first capacitor and a second capacitor, wherein the switch circuit is coupled to the first and second capacitors, the switch circuit is controlled by a first clock signal and a second clock signal, which is an inversion signal of the first clock signal, and a voltage variation of a first terminal of the first capacitor is coupled to a first terminal of the second capacitor based on a conduction state of the switch circuit; an analog-to-digital converter (ADC), coupled to the capacitive voltage divider, converting a voltage of the first terminal of the second capacitor into a first digital signal; and a processing module, coupled to the ADC, detecting a capacitance of the second capacitor and a capacitance variation of the second capacitor according to the first digital signal of the ADC and a parameter of the ADC. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An electronic device, comprising:
-
a capacitor under test, outputting a voltage under test; a sensor, outputting a sensing signal; a multiplexer, coupled to the capacitor under test and the sensor, outputting one of the voltage under test and the sensing signal; and an analog-to-digital converter (ADC), coupled to the multiplexer, converting one of the voltage under test and the sensing signal into a digital output signal, which represents one of a capacitance of the capacitor under test and a capacitance variation of the capacitor under test, and a sensed result of the sensor. - View Dependent Claims (7)
-
Specification