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I used a TTP223 IC operating on 5 V. I use the touch IC output (when high) to turn on the LED and (when low) to dim the LED. The LED is operated by the external 5 V. It uses only the touch IC output as a signal. I used a blue LED. What is the problem?

It works fine when turned on, but after several days the touch output hangs.

enter image description here

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1 Answer 1

Reset to default
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ESD can be a latchup problem.

Place a thin film (tight) over the sensor, adjust shunt cap for sensitivity then retest.

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  • \$\begingroup\$ I also try 30 PF shunt cap in parallel with Touch Input pin but sensitivity going down , any other Ideas? that helps to solve out the problem. \$\endgroup\$
    – Jaimin
    Commented Sep 17, 2019 at 4:29
  • \$\begingroup\$ Eliminate caps for max sensitivity and use glass for lower capacitance. But eliminate static discharge somehow. Separate issues \$\endgroup\$
    – D.A.S.
    Commented Sep 17, 2019 at 7:35

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