3 Replies Latest reply on Nov 19, 2018 7:07 PM by ShifangZ_26

    Direction of MOSFET in CCG3

      Hello,

       

      I am checking the circuite described in CCG3 datasheet.

      Compairing Figure 2 and Figure 15, there are two MOSFETs connecting to VBUS_P_CTRL but the diection is different.

       

      In Figure 2,   DC-DC <-> Source-Gate-Drain <-> Drain-Gate-Source.

      In Figure 15, DC-DC <-> Drain-Gate-Source <-> Source-Gate-Drain.

       

      Which flow is correct or recommend?

       

      Best regards,

        • 1. Re: Direction of MOSFET in CCG3
          ShifangZ_26

          Hi ,

           

          We are recommend to DC-DC <-> Drain-Gate-Source <-> Source-Gate-Drain.

          Below circuits for your reference.

           

          Best Regards,

          Lisa

          • 2. Re: Direction of MOSFET in CCG3

            Hello Lisa-san,

             

            Thank you for your prompt response.

             

            I think the following is general inquire but please let me know the reson.

             

            Q1) Why do you recommend the order, D-G-S, S-G-D?

             

            Q2) Why do we need 2 MOSFET on the line?

             

            Q3) The current on N-MOS flows Drain to Sorce because gate voltage should be higher than source voltage.

                 Why 2nd MOFET conneting to VBUS_P_CTRL1 is sorce is connected to DCDC?

             

            Best regards,

            • 3. Re: Direction of MOSFET in CCG3
              ShifangZ_26

              Q1) Why do you recommend the order, D-G-S, S-G-D?

              >> If I recommend to use S-G-D, D-G-S. there are two cases and fake (The current will streaming through body-diode) one of N MOS FET in this case:

              The current from left to right, the first N MOS FET is fake.

              The current from right to left, the second N MOS FET is fake.

               

              Q2) Why do we need 2 MOSFET on the line?

              >> If there is only one MOS FET, you will lose above explain for both direction. This is the risk. We only design with best practice.

               

              Q3) The current on N-MOS flows Drain to Sorce because gate voltage should be higher than source voltage.

                   Why 2nd MOFET conneting to VBUS_P_CTRL1 is sorce is connected to DCDC?

              >> Please kindly notice that all of VBUS_P_CTRL1/2 of CCG3 is connected to CCG3.

               

              Best Regards,

              Lisa