Patent ID: 8878556
Filing Date: 2014-11-04
Classification: G01D,G06F,H03K

Abstract:
1. A sensing device comprising: an oscillator comprising an input and an output, the input being coupled to a reference capacitor; a driver coupled to the reference capacitor, and input and the output of the oscillator, the driver alternately sourcing and sinking current in accordance with an oscillation signal outputted by the oscillator; a switch disposed between the reference capacitor and a sensing capacitor and configured to connect or disconnect the reference capacitor with the sensing capacitor; a counter coupled to the output of the oscillator and configured to count value for the oscillation signal; and a timer coupled to the counter and configured to count operation periods respectively when the switch connecting the reference capacitor with the sensing capacitor and when the switch disconnecting the reference capacitor with the sensing capacitor, the counter being configured to count values corresponding to conditions of the switch connecting and disconnecting the reference capacitor with the sensing capacitor during the operation periods, respectively.