Passive RC averaging of the TSENSE output yields the analog position output
| Authors | Stephen Woodward |
| Main Document | Article «Capacitive position sensor with linearized output» |
| Description | Figure 2 |
| File Format / Size | PDF / 19 Kb |
| Document Language | English |
Other Materials from the Main Document
- Article «Capacitive position sensor with linearized output»
- Figure 1. The U1a and U1b cross-coupled Schmidt trigger timers form a ~1 MHz RC multivibrator. The TSENSE pulse width is inversely proportional to sensor displacement
- Figure 2. Passive RC averaging of the TSENSE output yields the analog position output
- Figure 3. This graph shows the sensor performance when OUT is connected to a 12 bit ADC using +5 V for its reference. The black curve (left axis) equals the plate separation (d) in millimeters. The red curve (right axis) equals the ADC lsb resolution in micrometers
- Figure 4. Averaging integrator A1 linearizes the displacement sensing response. R5 is shown as a precision type, albeit just out of force of habit. It, like the ON resistances of U2's switches, actually cancels out
- Figure 5. In this graph of the enhanced circuit results, the black curve equates to the sensor readout d in mm, with red at a constant 1 mV per micron resolution