Analog signal conditioning with diagnostics for capacitive sensor elements

摘要

A system includes multiple capacitive sensors, a multiplexer, a programmable gain amplifier, an oscillator, a switch, and a controller. The sensors are coupled to the multiplexer, the multiplexer is coupled to the switch, and the switch is coupled to the amplifier and the oscillator. The controller may control the multiplexer to select each of the sensors. The controller may control the switch to activate the amplifier or the oscillator. The controller may measure voltage output by the amplifier or frequency output by the oscillator. The system may be included in an occupant support such as a vehicle seat.