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CCS/TMS320F28379S: FET fail in H-Bridge for motor control

PaulLee
Intellectual 480 points

Part Number: TMS320F28379S

Tool/software: Code Composer Studio

Hi, Experts,

I am developing the motor control firmware on F28379S.

I attached the H-brdige circiut.

My DC motor's power spec. is 12Vdc and my hardware can accept 12~24Vdc power.

For 24Vdc, my firmware supply PWM signal with 50% duty and for 12Vdc, my firmware will supply PWM to the motor with 100% duty.

Attached circuit has not catch diodes, but real board has these diodes.

When I supplied 24Vdc with 50% duty PWM, FETs has been broken.

I think that 24Vdc PWM with 50% is same effect with 100% 12Vdc  PWM.

What causes the impact to FET to be broken when supply 50% 24Vdc duty?

FET switch, LTC4449, does not turn on both FETs, Q1, Q3,  at same time.

FET can endure 40Vdc.

BR

Paul    

  • 0
    TI__Guru** 117280 points
    1. Please check if the deadband is inserted between high and low sides, and the delay time is enough for FET.
    2. Please check if the FET has an embedded freewheeling diode.
    3. Please check if the gate driver can work well on this case, it seems like its power supply is just 5V.

    You might try the FET and its driver from TI that should have more options for you, even TI has some dedicated BDC module.
  • 0 in reply to Yanming Luo
    Intellectual 480 points

    Yanming,

    When I supply 12~14Vdc to H-Bridge, no happens any problem.

    But, up 15Vdc, FETs are damaged.

    I will consider your FET and driver ;)

    BR

    Paul