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  • TI Thinks Resolved

TPS65094: TPS65094 CH4 damage.

Part Number: TPS65094

Dear Sir

Please check TPS650941 circuit which is designed by my customer.

Conditions Vin = 6V and Vin = 12V

After downloading firmware, board power on make CH4 damage.

The pin24(PVIN4) become to 0 ohm. ( short to GND )

If enable CH3, the chip is not working

If not use the CH3 and CH4, the chip work normally with other channels.

Please help us to check what's problem.

Attached files are circuit and PCB layout.

tps65094x_EVM_v1.0.pdfTPS65094x_EVM_top.pdfTPS65094x_EVM_bottom_mirrored.pdfTPS65094x_EVM_top_silk.pdf

  • Thank you for your question. I need more clarification of the issue. When you mentioned DCDC4 is damaged, is it external component issue or PMIC issue. Can you double check if the external cap is shorted on DCDC4. Also, on the schematic you had provided, it looks like FBVR4 is labeled FB2. Can you double check.

    Are you enabling the rails by PMICEN pin and SLP_S4 signals? Can you also provide screen shots of DCDC3 output to check if the SW mode is trying to switch.

    Regards,
    Jay
  • In reply to Jayanth Kruttiventi:

    Hi Jay :

    We checked the schematic several times.
    We didn't find any problem.
    You say "it looks like FBVR4 is labeled FB2"
    means the schematic shown below ???
    If it is true, R36 open make FB4 dosen't connect to FB4_O.

    I think is PMIC issue. Is it possible the problem comes from soft?
    The soft download from TI link, right ?
    http://www.ti.com/tool/ipg-ui

  • In reply to Terry Tseng:

    the chip is tps 650941 k 1 it looks like FBVR4 is labeled FB2. Can you double check.// i did not found FBVR4 ,,Whether does the FB2 mean the FBVOUT2 ?

    2Can you double check if the external cap is shorted on DCDC4//no short
    3 Can you also provide screen shots of DCDC3 output to check if the SW mode is trying to switch//What is it ?
    4 .Are you enabling the rails by PMICEN pin and SLP_S4 signals?//YES see the r1 and r5 in the sch
    5 by the way if the pgnd_buck3 and pgnd_buck4 are not well soldered to system dgnd of board , whether will it result the error of buck3 and buck4 But the buck5 is working well

    6 there is no switching signal with buck 3 when set the vr_ctrl1 register to 0X27 , set the vr_ctrl2 to 0XB7
  • In reply to user5165638:

    1. I think the FBVR4 Jay is referring to is the J9 jumper that you pointed out. It looks like the wire is labeled correctly so I don't think it should cause an issue. From what I can tell it looks like it is connected correctly in the layout as well.

    2. Can you check C4, C6, and C20 as well as C5? All of those caps are connected to the PVIN4 pin through the VIN_BUCK345_ANA net so if any of them are bad it could cause a short on PVIN4.

    3. The switch node Jay is referring to is LX3.

    5. When you say pgnd_buck3 and pgnd_buck4 do you mean the ground connections to their output caps? I don't see any pgnd_buck3 or pgnd_buck4 in the schematic. Also if PVIN4 is shorted then I would expect BUCK5 shouldn't be working either. BUCK3,4,5 are all connected to the same supply so if the input to one was shorted then they should all be shorted.

    I don't think it would be a software issue. If you can send a register dump from IPG-UI after the issue occurs on BUCK3 that might help us identify what is happening.

    Thank you,
    Nick
  • In reply to Nick Jakse:

    1  yes  FBVR4 connection is ok  

    2 The c4 ,c6,c20 and c5  are  ok 

    3 There is no switching signal  with lx3

    4 The  pgnd_buck3 and pgnd_buck4  are  drew   in the block   diagram  of  tps65094x

    5 when enable buck3., the Other bucks  arenot working ( include buck1,2,,5,6)

    6 when 3 channel buck is not enabled , the buck 1.2..5 are ok 

    7  when the initial code downloaded .The channel 4 buck is  enabled  for some  seconds ,then the  4 buck  is always short  .  so two boards are burned off  with the chip , . We must cut the buck4 input power  trace  with other boards

    6 can you send the tps65094x initial code to us .  we want to compare it  with our code 

    thank you 

  • In reply to user5165638:

    The best place to see what the initial code is for the device is to look at the datasheet in section 6.7 "Register Map". This shows what all of the registers should be set to as soon as you turn on the device.

    www.ti.com/.../tps65094.pdf

    You can also connect to the PMIC and click the "Read All" button in IPG-UI and then go to Report>Dump Registers to create a file with all of your register contents. This would help us see what the PMIC is reporting after the issue occurs.

    I would also check to see if LX3 is getting shorted to GND. I am not sure how that would cause PVIN4 to short to GND, but it might explain why turning BUCK 3 off causes the other BUCKs to work.

    Thank you,
    Nick
  • In reply to Nick Jakse:

    1  According to the  spec ,write the  registers ,Because other bucks are  good ,but   the 3 buck and 4 buck  .are bad  What  is the writing  register sequence for tps65094*? please send it to us

    2 There are no  read button and IPG_UI  ,can you send the initial code of  TPS65094* to us? or you can download the dump registers from the IPG_UI  to us ?

    thank you .

  • In reply to user5165638:

    There isn't a default register writing sequence. The registers are written during manufacturing to default settings that should be there as soon as the device is turned on. Just in case there is an issue I took one of our EVMs, read all of the registers and put them into a register dump for you to compare to your device. 

    E2E_regdump.txt

    I also put these registers into a project file so you can open this project, and then click "write all" to set all of your device's registers to the default values.

    E2E.json

    To send us a file with your register dump you can follow the pictures below.

    Thank you,

    Nick

  • In reply to Nick Jakse:

    1The  *.txt file is about the  tps65086? Whether does the tps65086 comptabile with  the  TPS65094

    2  we checked the register  ,which mee the spec  .

    can you send the  TPS65094"S setting to us ?

    thank you 

  • In reply to user5165638:

    I just did another register dump to confirm this register dump is from the TPS54094.

    The TPS65094 is the same device as the TPS65086 with a different OTP. When you start a new project in IPG-UI, you need to select "TPS650860-1.1" as the device.

    If you could send a register dump from your device after the error occurs on BUCK3 I can look at what the PMIC is reporting as the issue. Also, have you tried probing the LX3 pin to see if it is shorted?

    Thank you,
    Nick

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