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TPS65023: static current is too high , even if connected DCDC_EN1 DCDC_EN2 DCDC_EN1 DCDC_EN3 LDO_EN to GND. there still 60mA

Part Number: TPS65023
Other Parts Discussed in Thread: TMS320C5517,

Hi expert

I design a tms320c5517 system with TPS65023, but I find current is so high , so I disconnected power connection with DSP . static power is still high . Even if I  connected DCDC_EN1 DCDC_EN2 DCDC_EN1 DCDC_EN3 LDO_EN to GND.  there still 60mA.

what wrong with my design ? could you help me understand?

regards

Rafl

  • Your schematic has a lot of optional resistors labeled "nop" or "NO-POP" on your schematic.

    My guess is that one or many of these resistors were accidentally assembled on the PCB.

    I am especially worried about cases like R59 and R356, where one of the resistors is 0-Ohm and the other one has a "NO-POP" label. If R59 is installed with a 0-Ohm resistor accidentally, then you have a short from VIN_EVM to GND.
  • Hi Brian

    Thanks for your response.

    nop for not install. I have try to remove r569,r555,r551,r570,r552,r560,r577,r576,r56,r55

    and connected r338,r317,r321,r324 to GND ,it's should disable DC1 DC2 DC3 and ldo.

    but there sitll 60ma. 

    regards

    Rafl

  • Rafl,

    I plugged in a brand new TPS65023EVM-205 with all the jumpers installed in the default positions (LDOEN = DCDC1_EN = DCDC2_EN = DCDC3_EN = On), and I measure 20-30uA typically. Occasionally this number goes up to 60uA (micro-Amps), but never 60mA.

    I doubt that you are having a unit conversion issue (between uA and mA), so there are a few other possibilities:

    1) you have a real-time clock (RTC) connected in your system that is drawing current (up to 30mA typical) from VRTC
    *I think this is the most likely cause because I can tie VSYSIN to the main VIN and pull >60mA from VRTC on the EVM.

    2) there is I2C communication occurring that causes the SCL & SDA lines to toggle and burn current
    3) there is still a load attached somewhere in the system. VINLDO --> to VLDO1/2 is a separate path that may not have been disconnected
    4) the device has been damaged due to an electrical over-stress (EOS) event by applying >7V to one or more of the TPS65023 pins
  • Hi Brian

    Thanks for your support . it's nice to hear your can got 20-30uA,

    • I sure it is not 60uA,it 60mA.
    • r59 is removed ,vsysin to connected to GND
    • r56,r55,r335,r336 is disconnected , so there no connection with for I2C
    • I have carefully check VLDO1 &VLDO2 trace ,there no load connected.
    • as you know ,I already turn DC-DC & LDO off,(LDOEN = DCDC1_EN = DCDC2_EN = DCDC3_EN = GND), still find VRTC =3.0v, But it's floating .should not drink current.

    I have attach board photo ,current measurment result and PCB attachement please check  ARMOR_WIRELESS_EDB.brd

  • Thanks for sharing these images. Some of the attachments did not appear to go through and show up as dead links.


    In my opinion, this board would be difficult to debug because there is a lot of stray solder on the PCB. This solder should probably be cleaned up before debugging further. Not just stray solder, but solder on pads where the component is NOT populated.

    However, I did identify one location that should be No Connect where there is a solder bridge:
    R557

    R557 connects TPS65023_VCC_1V8 to VDD_NANFLASH

    Although it appears R576 has been removed, the resistor is still connected to one of the pads and could easily be shorted somewhere else.

    I cannot see any scope shots, if you attached them, but I believe DCDC2 is Enabled and current is flowing through R557 to an active load.


    To debug this further, I would need to be looking at a PCB that is free of stray solder and solder on un-used pads.