3 Replies Latest reply on Nov 10, 2019 10:13 PM by RajathB_01

    CY4532 current limiting

    ShSt_4521256

      I have a CY4532 development kit and had a question on how current limiting is handled.  I can see for the type-C port the CYPD4126 monitors and controls the current for the type-C port.  My question is for the type-A port, is current limiting handled strictly by the regulator for the type-A port?  Our end application will use a different regulator for both ports and the integration for the type-C port seems straightforward, but I'm trying to get some clarity as to the different control options available from the CYPD4126 to the type-A regulator.    

        • 1. Re: CY4532 current limiting
          RajathB_01

          Hello,

           

          The Type-A port current sensing is done by a discrete circuitry and component INA199A3DCKR (U9 on the power board) that gives an overcurrent signal to the CCG3PA.

           

          The CYPD4126 does not do any current monitoring / limiting. Please note that it is only present for the function of CC - bootloading, over the Type-C port on the power board. The Power Delivery enabled Type-C port is the one on the main board, controlled by CYPD3171.

           

          Regards,

          Rajath

          • 2. Re: CY4532 current limiting
            ShSt_4521256

            Rajath,

             

            My apologies, in my haste I copy/pasted down the wrong part number but yes I was actually referring to the CYPD3171.  Sorry about that.  So the CYPD3171 monitors the output of the INA199A3DCKR, but my question is how the current limit is controlled as the I see the IPWM pin which controls the current limit of the SC8701QDER is connected to VCC_87, or essentially the bootstrap supply for that regulator.  So it appears the CYPD3171 monitors the current but doesn't actually control the current limit directly.

             

            In our application we are not likely to use the SC8701QDER as this part does not show up on any distributors websites so we need to find an alternate solution.  Most regulator solutions do not include a programmable IPWM current limit, so my issue is for most standard regulator solutions that do not have a programmable current limit, how is the CYPD3171 to control the current limit, are we to rely on the regulators internal current limit?  

            • 3. Re: CY4532 current limiting
              RajathB_01

              Hello,

               

              You are right that CCG3PA is only monitoring and limiting current at overcurrent thresholds for normal fixed contracts.

              For PPS contract, CCG3PA will be doing active current limiting, regulator will not be doing current limiting in any scenario.

               

              Regards,

              Rajath