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WEBENCH® Tools/TPSM53603: The output current of TPSM53603 does not reach 3A, or even 2.3a, what is the reason?

Part Number: TPSM53603

Tool/software: WEBENCH® Design Tools

Hi Ti
    Figure 1 is the circuit schematic diagram of 24V input and 5V output designed by weBench Power Designer using TPSM53603 chip. Figure 2 Is the schematic diagram designed by SNVU627B document. I bought components and welded them to the PCB board, and measured the output voltage 5V after adding 24V voltage to the input end.When I added a resistance of 2.2 ohms and 200 watts to the output, the voltage dropped from 5V to 4.66V.Figure 3 is the photo of another test power supply I fixed at 5V output and connected to this resistor. It can be seen from the photo that this resistor flows through 2.3A.FIG. 4 shows that I fixed the test power supply as constant current output 2.18A, because the output current was not enough, the power supply dropped from 5V to 4.5.This situation is the same as that of TPSM53603, indicating that TPSM53603 does not output 3A current at all, that is, it outputs about 2.2a current. It is said in the manual that TPSM53603 can output 3A current. I would like to ask why there is no output even of 2.5a.Using the above load resistance can output 2.3A, the output voltage will not drop.


  • HI

    1. can you show me how you measure the output voltage of TPSM53603, pls make sure you test the votlage at R139 to GND. 

    2. if resistor is 2.2ohm for 5V output , it only delveir 2,2A, if you have connecting resistor between the load and module, current will be lower.


  • Hi

    According to your suggestion, after inspection, it was found that the wires loaded to both ends of the chip output were too thin to bear the current of 2A. The problem was solved after line replacement.Thank you for your quick reply.