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Linux/TPS659037: TPS6590376ZWSR/TPS6590377ZWSR SMPS9 output 3.3V

Wei He
Prodigy 200 points
Part Number: TPS659037
Other Parts Discussed in Thread: AM5728

Tool/software: Linux

I am now in the development of AM5728, PMIC is not working properly, the use of TPS6590376ZWSR chip, SMPS9 3.3V output is not working now, the measured voltage is 1.37V (voltage may be peripheral leakage over the other SMPS), the output voltage is normal (only +VDD_MPU SMPS1, +VDD_DSP SMPS5, do not work).

 I use the 5V supply that reference schematic, the need to use TPS6590377ZWSR?

 

The following is my PMIC schematic

  • 0
    TI__Genius 16410 points

    Hello Wei,

    The block diagram you show is for TPS6590377, but you mention you are using TPS6590376 on your board.  I expect this is the source of your issue.  In TPS6590376 (Figure 1 in the user's guide), you will see that SMPS7 and SMPS9 are not connected, since they remain off.  I expect if you replace your unit with TPS6590377, then you will see SMPS9 working at 3.3V as expected.

    Note that if you use TPS6590377, SMPS7 is enabled by default.  In this case, I recommend grounding SMPS7_FDBK, since floating it while SMPS7 is active can cause abnormal switching.

    Regarding SMPS1 and SMPS5, they are both part of a dual-phase configuration of SMPS12 and SMPS45.  SMPS2 and SMPS4 are the master phases, and at ligt load only one phase will be switching.  This is why you see SMPS1 and SMPS5 are off.  But if you measure the output voltage of the combined rail, you should see the expected output voltage.

    Regards,
    Karl