CE66058 - Dynamically Switch CSD Bleed Resistor | Cypress Semiconductor
CE66058 - Dynamically Switch CSD Bleed Resistor
You can achieve the proper sensitivity for sensors in an end system that have a considerable difference in parasitic capacitance (Cp) by tuning the raw counts of each sensor to 60 to 70 percent of the maximum value. This code example describes a method that compensates for differences in sensor raw counts due to variations in Cp by scanning the sensors with different bleed resistors.
In some CapSense® designs, the dimensions of the sensing elements vary widely, which in turn causes variations in the Cp of the different sensors. For example, the Cp may vary because of a difference in size or the length of the trace from the button to the CapSense pin of the device.