Asus X550c - BQ24725A - low ACdrv signal

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  • ktmmotocross
    Boardkiller
    • Feb 2014
    • 3580
    • slovakia

    #1

    Asus X550c - BQ24725A - low ACdrv signal

    Hello.
    Have this laptop Asus x550c that wont switch dcline mosfets because of low ACdrv signal/0.93V/. ACdet=3V,ACOK=3V,VCC=19V. Looks like ic's/BQ24725A/ charger pump for ACdrv is broken but i change it and looks the same.

    How to get high acdrv signal?
    Attached Files
    Last edited by ktmmotocross; 05-26-2015, 01:56 PM.
  • meritosari
    Senior Member
    • Oct 2010
    • 774
    • Indonesia

    #2
    Re: Asus X550c - BQ24725A - low ACdrv signal

    I think you should try to replace new mosfet for AC_FET and BAT_FET

    Comment

    • ktmmotocross
      Boardkiller
      • Feb 2014
      • 3580
      • slovakia

      #3
      Re: Asus X550c - BQ24725A - low ACdrv signal

      i remove acfet and test it. it is good

      i read in datasheet that Vacdrv=Vcmsrc+6V but i have Vcmsrc=0.93V

      Comment

      • meritosari
        Senior Member
        • Oct 2010
        • 774
        • Indonesia

        #4
        Re: Asus X550c - BQ24725A - low ACdrv signal

        yes if you have the test results are not short, but in my opinion, gate charge problematic. maybe...

        Comment

        • saularciga
          Senior Member
          • Feb 2014
          • 55
          • mexico

          #5
          Re: Asus X550c - BQ24725A - low ACdrv signal

          posted diagram please

          Comment

          • saularciga
            Senior Member
            • Feb 2014
            • 55
            • mexico

            #6
            Re: Asus X550c - BQ24725A - low ACdrv signal

            Originally posted by ktmmotocross
            i remove acfet and test it. it is good

            i read in datasheet that Vacdrv=Vcmsrc+6V but i have Vcmsrc=0.93V
            Is true , In the gate should have 19 vcc + 6V

            Comment

            • saularciga
              Senior Member
              • Feb 2014
              • 55
              • mexico

              #7
              Re: Asus X550c - BQ24725A - low ACdrv signal

              Check the capacitor near area of mosfets

              Comment

              • meritosari
                Senior Member
                • Oct 2010
                • 774
                • Indonesia

                #8
                Re: Asus X550c - BQ24725A - low ACdrv signal

                Originally posted by ktmmotocross
                Hello.
                Have this laptop Asus x550c that wont switch dcline mosfets because of low ACdrv signal/0.93V/. ACdet=3V,ACOK=3V,VCC=19V. Looks like ic's/BQ24725A/ charger pump for ACdrv is broken but i change it and looks the same.

                How to get high acdrv signal?
                acdet a little high, i think must be arround 2.6v so check resistor first
                Last edited by meritosari; 05-28-2015, 11:26 AM.

                Comment

                • ktmmotocross
                  Boardkiller
                  • Feb 2014
                  • 3580
                  • slovakia

                  #9
                  Re: Asus X550c - BQ24725A - low ACdrv signal

                  acdet must be 2.4-3.15v

                  Comment

                  • dycc
                    Vision
                    • Nov 2011
                    • 625
                    • Côte d'Ivoire

                    #10
                    Re: Asus X550c - BQ24725A - low ACdrv signal

                    replace mosfet as metitosari said . they might seem good if you check, but can have gate issue

                    Comment

                    • ktmmotocross
                      Boardkiller
                      • Feb 2014
                      • 3580
                      • slovakia

                      #11
                      Re: Asus X550c - BQ24725A - low ACdrv signal

                      what is "gate issue", i test it with multimeter and works fine

                      Comment

                      • Esse
                        Badcaps Veteran
                        • Apr 2014
                        • 317
                        • TOGO

                        #12
                        Re: Asus X550c - BQ24725A - low ACdrv signal

                        dycc,what is it the gate issue

                        Comment

                        • whaldsz
                          Badcaps Veteran
                          • Apr 2013
                          • 395
                          • Philippines

                          #13
                          Re: Asus X550c - BQ24725A - low ACdrv signal

                          Could you check the resistance to GROUND of ACDRV and CMSRC pin?

                          Comment

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