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  • TI Thinks Resolved

DRV10970EVM: no 5V VINT on the board

Intellectual 300 points

Replies: 5

Views: 700

Part Number: DRV10970EVM

I got my evaluation board and provided 12V power supply.  However VINT is only about 0.19V.  During my power ON and OFF through S1 switch, I did see the VINT =4.97 V at one point but that is.   The board is so simple and I have no clue what I should do.  This is the new board I just got.  Any suggestion of how to troubleshoot and any chance for me to get a replacement board?   

Note that I measure VINT at VIINT pin of J6, where VINT and V_HALL can be connected or not.

thanks, 

Hong 

  • Hong,

    It sounds like the device is in sleep mode. Can you turn the potentiometer (R1) to the middle and verify that there is a PWM signal applied to DRV10970? Monitor the test point TP 3 (PWM).

    Thanks,

    Brian

  • In reply to Brian Schmidt:

    Hello Brian,

    I double checked and the POT is in the Middle position.  There is no PWM signal either on test TP3 (zero V DC) .  And there is no trace on my oscillscope of PWM even if I recycle power using S1 switch.   by my reading the user guide of the evaluation board, the one board PWM generates 25Khz pwm signal with 5% to 95% duty cycle therefore it is NOT going to generate 0% duty cycle signal.     if there is no VINT, then there is no PWM as the timer chip using VINT as its VCC.    Or in another word, if PWM run into sleep mode, then it will never recover. 

    At one point, I did measure VINT=5V  consistently for a while when I removing CTMOD jumper and VINT = ~0V when I put the CTMOD jumper back at 1-2 position.   However later VINT=0 no matter what.  

    At this point nothing connected to the EVM board and none of jumper is put on.    POT is at its middle position.  VM=12 is present to the board.   Any tips how I should troubleshoot the problem?

    thanks,

    Hong

  • In reply to Hong Sun:

    Hong,

    Here's is what I would suggest:

    • Measure supply current (is it mA or uA)? Just trying to determine if the device is asleep or not.
    • Measure VM after the switch. Is it 0V or 12V?
    • If 0V check fuse.

    This is a pretty simple straight forward device so I don't see much else we can check. I guess there's a possibility that a device has gotten damaged.

    Let me know about the 3 items above.

    Thanks,

    Brian

  • In reply to Brian Schmidt:

    Hello Brian,

    Vm after the switch is 12V.     While trying to feed pwm through external DC to test if the circuit ends up in a dead loop: no PWM somehow --> sleep and no VINT  --> no VINT for sure gives no PWM  --> sleep mode, I changed the VM to 5V for my test and then everything behaves before my trying to test external PWM: there is PWM and VINT.   increase my VM to 12V then no PWM and VINT.     change VM between 12 to 5V several times and it always works with VM=5 . 

    I don't know what is going on with this board but it shouldn't behave like this.  any chance for me to get a replacement?

    thanks,

    Hong

  • In reply to Hong Sun:

    an update on the defected board or DRV10970 chip I got on the DRV10970EVM board.  and hopefully it might help the others who might get a defected board:

    using oscilloscope to check Vm and VINT on the board during S1 switch is switched ON:

    when Vm<=9 Volts, VM steps up to 9 V with Vint ramp up to 5 V in micro-seconds.

    when Vm=12 V, Vm steps up to 12 V with Vint stays zero.

    thanks,

    Hong 

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