Patent ID: 9116188
Filing Date: 2015-08-25
Classification: G01R,H03K

Abstract:
1. 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; 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; and a touch screen, wherein the capacitor under test is disposed within the touch screen; wherein: the capacitor under test is inside a capacitance evaluation circuit; the capacitance evaluation circuit further comprises: a processing circuit, coupled to the ADC, for detecting the capacitance of the capacitor under test and the capacitance variation of the capacitor under test according to the digital output signal of the ADC and a parameter of the ADC; the parameter of the ADC comprises a resolution and a full scale of the ADC; and the processing circuit further detects the capacitance of the capacitor under test and the capacitance variation of the capacitor under test according to a voltage value of a first voltage source of the capacitance evaluation circuit, a voltage value of a second voltage source of the capacitance evaluation circuit, a capacitance of a known capacitor of the capacitance evaluation circuit, the resolution of the ADC, the full scale of the ADC and the digital signal of the ADC.