DRV8301 has fault in my board

amos lin

Other Parts Discussed in Thread: BOOSTXL-DRV8301, TMS320F28027F, MOTORWARE

Hi all,
    Now I am transplanting from "C2000 LaunchPad XL TMS320F28027F + BOOSTXL-DRV8301 REVB" to my board.

The attachment is my schematic and layout, and external MOSFET is AOD444.

I use MotorWare Lab3a to do adc calibration, no modify anything. I got some questions:

Q1. DTC Resistor
The original DTC resistor is 1 ohm, if I use 1 ohm, all input pwm(INH_A/INL_A/INH_B/INL_B/INH_C/INL_C) are strange.
The fig1 is 1 ohm, the fig2 is 150k ohm in attachment.
When DTC is 1 ohm, the fault is always lighting after system run.
When DTC is 150k ohm, the fault is blinking after system run.

if DTC is 150k ohm, the calibrated value are
        I_A_offset    0.7939509749
        I_B_offset    0.7900301218
        I_C_offset    0.8347318172

        V_A_offset    0.4812804461
        V_B_offset    0.4496791959
        V_C_offset    0.4856731892

Q2. PWM Clock
Condition: DTC is 150k ohm.

Then I run Lab2a to do parameter auto tune. In this mode, the current of power supply has overcurrent fastly.

If I modified (in HAL_setupPwms())
      PWM_setHighSpeedClkDiv(obj->pwmHandle[cnt],PWM_HspClkDiv_by_1);
      PWM_setClkDiv(obj->pwmHandle[cnt],PWM_ClkDiv_by_1);
to
      PWM_setHighSpeedClkDiv(obj->pwmHandle[cnt],PWM_HspClkDiv_by_4);
      PWM_setClkDiv(obj->pwmHandle[cnt],PWM_ClkDiv_by_4);

the fault is darked, and the calibrated value are
        I_A_offset    0.8521981239
        I_B_offset    0.8434513211
        I_C_offset    0.8367571831

        V_A_offset    0.5026167631
        V_B_offset    0.4560748935
        V_C_offset    0.4990658164

Then I run Lab2a to do parameter auto tune. In this mode, motor can be exciting, and rotate with low speed.
After some time, the current of power supply has overcurrent.

I don't know what happened, does anyone can help me?

Thank you.

demo.zip

over 8 years ago

0 Nicholas Oborny over 8 years ago

TI__Mastermind 21305 points

Amos,

The DTC resistor controls the dead time inserted into the outputs.

1 Ohm should be fine for most applications. I suspect some other issue may be at play.

Can you read what fault is being reported?

What do you mean by the inputs are strange? The DTC resistor should have no effect on the inputs? Can you post a scope capture? If the DTC resistor is having an effect then it might point toward shoot-through occuring?

Did you directly copy the Launchxl and boost schematics? What other changes were made?

Can you attach you schematic and layout in pdf format. I cannot read the format that is attached.