| 摘要 |
A capacitive sensing device comprises an antenna electrode (12) for emitting an alternating electric field in response to an alternating voltage caused in the antenna electrode and a control and evaluation circuit (18) configured to maintain the alternating voltage caused in the antenna electrode equal to an alternating reference voltage on an alternating reference voltage node (22) by injecting a current into the antenna electrode (12) and to measure the current. The control and evaluation circuit (18) includes a microcontroller (30) with a digital output (28) for providing a digital signal and may include a low- pass filter (26) operatively connected to the digital output (28) for generating the alternating reference voltage by low-pass-filtering the digital signal. The control and evaluation circuit (18) further includes a first multiplexer (48) and a second multiplexer (200). |
