This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65218: TPS65218 don´t start if VBAT over 4.4Vdc

Part Number: TPS65218

I´m using the same configuration of SK AM437x, with processor AM4376BZDNA100.

The main power suplly is 5Vdc

To power ON I used the PB signal, but the board just come up if VBAT < 4.4Vdc.

See my schematic sheet

6038.Schematic.pdf

  • I don't see VBAT on your schematic and the PDF is not searchable.

    The diagram in Figure 5-35 of the datasheet (on page __) shows that when power is first applied, the only condition is that "VIN_BIAS > UVLO + hysteresis" .

    In your schematic, IN_BIAS is connected to +5VDC, so the TPS65218 PMIC will turn on when the +5VDC voltage > UVLO + hysteresis, which is a max value of 3.45V + 400mV = 3.85V
  • Hi;

    I fixed VBAT as +5VDC . There is no variation on power supply.

    +5VDC > 3.85V !

    What need I to change to PMIC start ? Not clear

  • In your first post you said "the board just come up if VBAT < 4.4Vdc."

    To me, this means the PMIC has started.

    You will need to clearly define the problem so that I can assist further.

    If the output rails of the PMIC are not turning on or staying on, then you will need to verify that the PWR_EN pin is asserted High (logic '1'). The PWR_EN pin is typically set high by the processor "PMIC_PWR_EN" signal after the "nWAKEUP" output of the PMIC has been asserted Low (logic '0') due to a wake-up event. This is a handshake between the PMIC and Processor that occurs during every start-up sequence.