| 摘要 |
A pulse is applied through a capacitive touch key sensor to a sampling capacitor of an analog-to-digital converter (ADC). The voltage charge arriving at the sampling capacitor will be maximum when there is substantially no shunt capacitance between the capacitive touch key sensor and the sampling capacitor. However, a object such as an operator's finger when in close proximity to the capacitive touch key sensor will create a capacitive shunt to ground that diverts some of the charge that is supposed to go to the sampling capacitor and thereby reduces the voltage charge on the sampling capacitor. This change in charge voltage when the capacitive touch key sensor is activated (touched) may be easily detected with the ADC. In addition, light emitting diodes (LEDs) may be integrated with the capacitive touch key sensors and use the same connections on an integrated circuit device in a time division multiplexed manor. |
