Author Topic: "Protecting" capacitive touch buttons from LED PWM signal  (Read 864 times)

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Offline 3dgeoTopic starter

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"Protecting" capacitive touch buttons from LED PWM signal
« on: February 26, 2019, 08:43:09 pm »
Hi,

I'm working on a project where I'm using cap touch buttons and RGB LED near them.
I found that it's recommended to use 10nF bypass capacitors on LED leads to reduce LED power lines influence on touch pads.
Each pin of a LED is PWMed – anode about 500 Hz, cathodes 100-200 kHz. Will 10nF cap do any good in this situation or it will mess things up?

Currently LEDs are in the middle of the Tpad, but on a next revision I will add on top of LEDs another PCB (will be 2.4mm gap between PCBs) with Tpads and ground on a bottom to reduce influence.

Don't know if this makes any different but TP ICs I'm testing is TTP229-LSF and TS20.

Ideas?


 


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