• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 30 subscribers
  • Views 454 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.

DRV8144-Q1: Thermal, slew rate, and application clarifications

Kyle Pall
Prodigy 550 points
Part Number: DRV8144-Q1
Other Parts Discussed in Thread: DRV8145-Q1

Hello,

I had a couple quick questions regarding this part:

1. Is there any reason why this device (or half bridge drivers in general) cannot be a driver for a heated seat solution? From what I can tell it should work fine.
2. I tried checking with the thermal calculator tool, but we wanted to confirm that the device will remain under thermal limit when there is a 1.5-ohm resistor on the low side, and it is being driven by 10A PWM at a very low frequency (<1Hz) with a duty cycle of 90%. Is this true?
3. Concerning the varying slew rate, would you recommend utilizing the SPI version or the hardware version for the 1.3 V/us slew rate in this application?

  • 0
    TI__Mastermind 19510 points

    Hi Kyle,

    The limiting factor to consider is the transient thermal impedance current capability. In the PWM mode the DRV8144-Q1 is only capable of driving 6.8 A DC, any higher and this could lead to damaging the device. 

    More information on this can be found in section 7.5.14 of the datasheet. I have included a screenshot below for convenience:

    Best,

    David

  • 0 in reply to David Medis
    TI__Prodigy 550 points

    Hi David,

    Thank you so much for the response. I have a few follow up questions:

    1. Would the move to the DRV8145-Q1 would be better to account for the higher current in this scenario?
    2. Will <1Hz PWM really add much switching losses to the system?

    Thank you for your assistance,

    Kyle 

  • +1 in reply to Kyle Pall
    TI__Mastermind 19510 points

    Hi Kyle,

    Kyle Pall said:
    Would the move to the DRV8145-Q1 would be better to account for the higher current in this scenario?

    Yes, the DRV8145-Q1 would be better suited for a higher maximum current, however the rms current would need to be considered. 

    The current capability of the DRV8145-Q1 with PWM DC can be thought of as the rms current capability. It is not recommended to run a continuous DC current with PWM higher than 7.9 A.

    Kyle Pall said:
    Will <1Hz PWM really add much switching losses to the system?

    The following app note will provide all the information needed to calculate power losses:

    https://www.ti.com/lit/an/slva504a/slva504a.pdf 

    Best,

    David