• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 869 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8432: DRV8432 driving 2 TEC: Output duty cycle is limited in a very low level

user5140768
Prodigy 50 points

Part Number: DRV8432

Hi TI experts,

We are using DRV8432 to drive 2 TECs seperately, which supports both heating and cooling.  In our design, DRV8432 is set in mode 1(M1=M2=M3=0), dual full bridges with cycle-by-cycle current limit.

At first, it works so fine. Cooling/Heating power is controlled by the duty cycle of PWM input to DRV8432.

But somehow, in one of my board, the duty cylcle of OUT_X is fixed at a very low value (about 10%), no matter how we changed the PWM input duty cycle. And if the duty cycle is zero(PWM_X = low), the OUT_X will be low. This means DRV8432 is working. But the output duty cycle is limited in a very low level.

And the OTW and FAULY are still high, which means device is under normal operation.

Do you have any idear about this?

Thanks.

BR,

Jon

  • 0
    TI__Guru** 114905 points
    Hi Jon,

    "But somehow, in one of my board, the duty cylcle of OUT_X is fixed at a very low value (about 10%), no matter how we changed the PWM input duty cycle. "

    Does this mean you have some boards that work properly and one that does not?
    Have you monitored the current to see if the OC_ADJ could be causing this?
  • 0 in reply to Rick Duncan
    TI__Expert 4435 points
    Hi Jon,
    We haven’t heard back from you, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out) – thanks