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Original question:

DRV8302: Buck converter output voltage issue

DRV8302: 3-Phase Driver internal regulator issue

Vijay pawar
Prodigy 120 points
Part Number: DRV8302

Hi,

I am using DRV8302 for Gate driver circuitry as well as Buck Regulator.

At the beginning the circuit was working OK, but during testing my motor stopped working and i found this issue.

The current sensing circuit was not working properly .The output voltage of Current sense amplifier (SO1 & S02) is showing 0V.??

where my reference voltage is 5V. So as per the datasheet the when the current is 0A the output of Current sense amplifier should be 2.5V, but here it is 0V ?? How ?? also the Voltage across GVDD and AVDD is 0V. 

The input voltage at PVDD is 24V. 

Kindly suggest any solution for this also any measure that need to take to avoid such issue in future

  • 0
    TI__Mastermind 18900 points
    Hey Vijay,

    An expert has been notified and should get back to you as soon as they can.

    I also encourage you to please provide some more information regarding the input of the current sense amplifier (SN, SP, and DC_CAL), including intended voltage levels if possible. The equation for the output of the current sense amplifier is given in the datasheet, what's your expected output?

    Best,
    -Cole
  • 0 in reply to Cole Macias
    Prodigy 120 points
    Hello Sir,

    Thanks for your valuable reply.

    DC_CAL pin is connected to MCU. and it is Logically LOW.

    I have connected SN1 and SP1 pins across Shunt Resister of value 0.020 Ohm. SP1 is connected to ground.
    For 2A load current , my expected output voltage at SO1 is 2.3V.

    As I am using my application in Single Shunt configuration , Only one current sense amplifier is Using , hence SN2 and SP2 pins are connected to ground.


    Regards,
    Vijay
  • 0 in reply to Vijay pawar
    TI__Guru 61380 points
    Vijay,

    Are you stating that your AVDD and GVDD pins each show 0V?

    Regards,

    -Adam
  • 0 in reply to Vijay pawar
    TI__Guru 61380 points
    Vijay,

    AVDD is an internal regulator, if the chip is working correctly then it should output 6V whenever the PVDD1 power is valid. GVDD is the same but it's voltage is closer to 11V.

    It seems your DRV might be damaged or not powered correctly. Can you try a second device?

    Regards,

    -Adam
  • 0 in reply to Adam Sidelsky
    Prodigy 120 points
    Hello Adam,

    The device is correctly powered. In my above queries i had mentioned it that, My device was working OK. but during my testing ,System stopped suddenly, after analyzing it i came to know that the voltages at the respective pins were 0V. I want to Know ,In what case does the internal voltage regulator can damage.??

    Supply voltage is 24V at PVDD1.
  • 0 in reply to Vijay pawar
    TI__Guru 61380 points
    Vijay,

    It is too difficult to predict why the device would have been damaged. We sometimes see devices being damaged if there are excess voltage spikes on the device pins due to overshoot or undershoot due to motor voltage or similar. If the motor is not slowed down correctly then the spinning motor can generate voltage back into the device that can damage it.

    Regards,

    -Adam