Capacitance difference detecting method

Abstract

A capacitance difference detecting method, comprising: (a) utilizing a voltage control unit to cooperate with a first capacitor to be detected and a second capacitor to be detected to generate a first voltage and a second voltage; and (b) computing a capacitance difference between the first capacitor to be detected and the second capacitor to be detected according to the first voltage, the second voltage and a parameter of the voltage control unit.

1 . A capacitance difference detecting method, comprising:
 (a) utilizing a voltage control unit to cooperate with a first capacitor to be detected and a second capacitor to be detected to generate a first voltage and a second voltage; and   (b) computing a capacitance difference between the first capacitor to be detected and the second capacitor to be detected according to the first voltage, the second voltage and a parameter of the voltage control unit.   
     
     
         2 . The capacitance difference detecting method of  claim 1 , wherein the step (a) further comprises comparing the first voltage and the second voltage, and changing the parameter of the voltage control unit according to a comparison result, to control the first voltage and the second voltage respectively to be a predetermined value. 
     
     
         3 . The capacitance difference detecting method of  claim 1 , wherein the voltage control unit is an adjustable capacitor, and a capacitance value of the adjustable capacitor is controlled by the control signal; where capacitance values of the voltage control unit, the first capacitor to be detected and the second capacitor to be detected determine the first voltage and the second voltage. 
     
     
         4 . The capacitance difference detecting method of  claim 3 , wherein capacitance values of the voltage control unit, the first capacitor to be detected and the second capacitor to be detected cause the first voltage and the second voltage to be the same. 
     
     
         5 . The capacitance difference detecting method of  claim 1 , further comprising:
 providing a first constant capacitor and a second constant capacitor, wherein the step (b) computes capacitance difference between the first capacitor to be detected and the second capacitor to be detected according to voltage values of the first voltage and the second voltage, a parameter of the voltage control unit, the first constant capacitor and the second constant capacitor.   
     
     
         6 . The capacitance difference detecting method of  claim 5 , wherein the first constant capacitor and the second constant capacitor are parasitic capacitors.