I have a small LED lighting board which has a CY8CMBR3108 as a toggle switch to control the light. The board operates will within the temperature limits of all components. However, when the light is activated by a touch, the board heats up relatively quickly due to the LED power etc.
What seems to happen is that the raw count slowly climbs with temperature and the automatic calibration cannot keep up. Finally after about a minute or so, the capsense falsely senses a touch and turns the light off. I have included a screen shot of the raw count log to show what I mean.
I have played around with all of the configuration options that I can find with no real luck. I have also tried adding parasitic capacitance and series resistance to the sensor in different combinations. Nothing has seemed to help.
Is there anything I can do to resolve this issue?
Is MBR3 connected to other host through I2C BUS or just a single-chip design? If it is a single-chip design, seems there is no good way to fix it. You can try to reduce the temperature rise rate of the touch button(for example change FPC board to PCB board or use thick overlay), or replace it with a programmable chip.