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TDA4VH-Q1: PMIC startup issue for TDA4VH

wang kun
Prodigy 140 points
Part Number: TDA4VH-Q1
Other Parts Discussed in Thread: TDA4VH

Tool/software:

TI experts：

TDA4VH power supply design with 3A PDN.But the main domain power startup is abnormal .By using GUI tools read register configuration ,display the buck3 overvoltage interrupt. 

Obtain the waveform of buck3 as below.

Disconnect both load of VDD_RAM_0V85 power supply and find that the actual output voltage of buck3 is 3V3 with 15 pulse.15 pulse are caused by abnormal load .but why is the voltage 3V3 when there is no load?

by checking the TPS6594 register configuration ,BUCK3_VSET1  = 0x41,which is the same as the configuration in PDN.

  • 0
    TI__Mastermind 25665 points
    wang kun said:
    Disconnect both load of VDD_RAM_0V85 power supply and find that the actual output voltage of buck3 is 3V3 with 15 pulse.15 pulse are caused by abnormal load .but why is the voltage 3V3 when there is no load?

    This sounds like a problem with the BUCK3 FB connection. If the pin is shorted to ground or measuring a low voltage, the output will match the input as the high-side FET will open up. 

    Can you share the portion of the schematic around BUCK3 and it's FB pin?