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PSoC™ 6 Forum Discussions

jacintal
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Hi,

For PSoC 6, in order to bump the capacitance of our custom sensor to be above 5 pF which could be optimized for 4th Gen CapSense, we were trying to parallel a fixed value SMT capacitor (5pF) to our sensor(2.5pF Mutual-cap). Would this method work since measuring only our sensor using CSX seem quite insensitive? If so, would the method we showed in the image be the correct way to do that?

Also, is it possible to determine the best IDAC value other than auto-calibration if the baseline capacitance and resistance of our sensor are known?

Thank you so much!

Screen Shot 2022-07-15 at 12.46.49 AM.png

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PandaS
Moderator
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Moderator

Hi  @jacintal ,

Yes, you can use the parallel capacitor method to increase the Parasitic Capacitance(Cp) of the Sensor for CSD sensing. It is fine and it would work. We usually do this by having a common external capacitor connector to a free GPIO Pin and while measuring Raw Counts we gang up the sensor pin and GPIO Pin together to achieve a Higher Cp value. This helps if you face similar issue in multiple sensors, and it is dealt by the Firmware.

 

And for Best IDAC value, you can start off with the smart sense value and then manually tune it and observe the performance. 

You can refer to the CapSense Design Guide - Performance Tuning Section.

https://www.infineon.com/dgdl/Infineon-AN85951_PSoC_4_and_PSoC_6_MCU_CapSense_Design_Guide-Applicati...

 

Warm Regards

Sobhit

 

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PandaS
Moderator
Moderator 100 sign-ins 25 solutions authored 10 likes received
Moderator

Hi  @jacintal ,

Yes, you can use the parallel capacitor method to increase the Parasitic Capacitance(Cp) of the Sensor for CSD sensing. It is fine and it would work. We usually do this by having a common external capacitor connector to a free GPIO Pin and while measuring Raw Counts we gang up the sensor pin and GPIO Pin together to achieve a Higher Cp value. This helps if you face similar issue in multiple sensors, and it is dealt by the Firmware.

 

And for Best IDAC value, you can start off with the smart sense value and then manually tune it and observe the performance. 

You can refer to the CapSense Design Guide - Performance Tuning Section.

https://www.infineon.com/dgdl/Infineon-AN85951_PSoC_4_and_PSoC_6_MCU_CapSense_Design_Guide-Applicati...

 

Warm Regards

Sobhit

 

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