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Original question:

TPS65094: TPS650944 VNN, VCCRAM, VCCGI no power

TPS65094: TPS65094 BUCk2 have no output power when change LPDDR4 from 16Gb to 32Gb

steven hsu
Prodigy 180 points
Part Number: TPS65094

HI 

we are now using TPS650940A0 in out intel platform with Apollo Lake,

originally we use LPDDR4 (  16Gb ) for 2 PCs, it work

Now we would like to validate 32Gb for 2 PCs ( i believe the power consumption will increase), but it's strange that BUCK2 will have no output power after we change the LPDDR4 components

But all other voltages are work

can you knidly advice if anything we need to pay attention with the DDR change ( 16Gb to 32Gb) ? we have measured the i2c bus but it just have high level but no signal

thanks.

steven

  • 0
    Prodigy 180 points

    HI Expert:

    i found a very similar figure in datasheet ( please ref to attached file, Figure 6.3.5.3), how to implement the " SET the VID by host"?
    Please kindly advice, thank you,.

    steven

  • 0 in reply to steven hsu
    TI__Mastermind 27780 points

    Hi Steven, 

    Thank you for reaching out via E2E. For this device BUCK2 (VCCGI) output voltage is default = 0V. The expectation is the processor will set BUCK2 output voltage via I2C write to BUCK2CTRL register (address offset 21 hex). Below I have included the relevant section of the datasheet. Further information on the I2C interface in general can be found starting on page 48 of the TPS65094 datasheet.

    I recommend reading the status of all I2C registers when you observe no voltage at BUCK2 and all other outputs are working. This will help determine if BUCK2 voltage has simply not been set by your processor or if there is some other reason why it does not output. 

    Regards,

    Garrett