2 Replies Latest reply on Mar 7, 2019 5:43 PM by YuMa_1534086

    Regarding solution of PSoC4S(CY8C4045AZI) capsense Diff/IDAC saturation.

    YuMa_1534086

      Hello

       

       

      Q1)

      Could you please let us know solution in case diff count with finger-touch saturated because sensitivity is too high.

       

      I think that there are the following methods.

      Please check whether they are correct or not.

      And could you please let us know if there are other solutions.

       

      -----------------------------------------------------------------------------------------------------------

      [IC tuning]

      - Decreased calibration target        (increased IDAC value)

      - Disabled compensation IDAC      (increased CP => increased IDAC)

      - Disabled shield                             (increased CP => increased IDAC)

       

      [Hardware]

      - Increased CP                                (increased IDAC value)

      - Changed overlay                          (decreased sensitivity)

      -----------------------------------------------------------------------------------------------------------

       

       

      Q2)

      Could you please let us know solution in case IDAC saturated

       

      I think that there are the following methods.

      Please check whether they are correct or not.

      And could you please let us know if there are other solutions.

       

      -----------------------------------------------------------------------------------------------------------

      [IC tuning]

      - Increased calibration target          (decreased IDAC value)

      - Enabled compensation IDAC       (Increased IDAC drive ability)

      - Enabled shield                              (decreased CP => decreased IDAC)

      - “Inactive sensor connection” changes from GND to shield.  (decreased CP => decreased IDAC)

       

      [Hardware]

      - Decreased CP                              (decreased IDAC value)

      - mesh pattern changes from GND to shield (decreased CP => decreased IDAC)

      -----------------------------------------------------------------------------------------------------------

       

       

       

      Best Regards.

      Matsubara

        • 1. Re: Regarding solution of PSoC4S(CY8C4045AZI) capsense Diff/IDAC saturation.
          RuzheZ_36

          Hello Matsubara-san,

           

          Comments below are FYI.

           

          Q1)

          Solution in case diff count with finger-touch saturated because sensitivity is too high.

          -----------------------------------------------------------------------------------------------------------

          [IC tuning]

          - Decreased calibration target        (increased IDAC value)                           - Correct

          - Disabled compensation IDAC      (increased CP => increased IDAC)         - Correct, but CP not increased. Software changing will not change CP.  See Figure 5-12 in AN85951(https://www.cypress.com/documentation/application-notes/an85951-psoc-4-and-psoc-6-mcu-capsense-design-guide )

          - Disabled shield                             (increased CP => increased IDAC)         - Correct, at the same time, it is better to connect mesh pattern with GND. If leave them float, CP will not be increased effectively.

           

          [Hardware]

          - Increased CP                                (increased IDAC value)                            - Correct

          - Changed overlay                          (decreased sensitivity)                              - Correct

          -----------------------------------------------------------------------------------------------------------

          Increasing CP or decreassing sensitivity(CF) is the best choice to solve diffcount saturated.

           

           

          Q2)

          Solution in case IDAC saturated

          -----------------------------------------------------------------------------------------------------------

          [IC tuning]

          - Increased calibration target          (decreased IDAC value)                                                                   - Correct

          - Enabled compensation IDAC       (Increased IDAC drive ability)                                                           - Correct

          - Enabled shield                              (decreased CP => decreased IDAC)                                                - Correct

          - “Inactive sensor connection” changes from GND to shield.  (decreased CP => decreased IDAC)       - Correct

           

          [Hardware]

          - Decreased CP                              (decreased IDAC value)                                                                    - Correct

          - mesh pattern changes from GND to shield (decreased CP => decreased IDAC)                                  - Correct

          -----------------------------------------------------------------------------------------------------------

           

          Thanks,

          Ryan

          • 2. Re: Regarding solution of PSoC4S(CY8C4045AZI) capsense Diff/IDAC saturation.
            YuMa_1534086

            Ryan-san.

             

            Thank you for your support.

            I understand.

             

            Best Regards.

            Matsubara