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Original question:

DRV8873-Q1: For TEC application, may we know how to set up HW&SW?

DRV8873-Q1: DRV8873 power calculation issue.

Chen Bogey8
Mastermind 9990 points
Part Number: DRV8873-Q1
Other Parts Discussed in Thread: DRV8873, , DRV8412

Hi Sir

DRV8873 issue: VM power supply=6V@9.5W,  IN1/2 duty cycle setting 50%.

VOUT1/2 path add LC filter, TEC_VOUT1=5.29V, TEC_VOUT2=2.88V, IPROP status output=2A, but fault occurred.

TEC(V(V)) : Vout1-Vout2= 2.41 V(V), to check TEC current about 1.5-2.2A, as attached file .calculator TEC power loss around 3.62-5.3W.

but VM power is 9.5W, IC isn't hot, May we know how to calculater power loss? (we main concern is if TEC consume is 5W, then it is mean IC will having 4W power loss,is it normal in this kind application?)

                                                                        Bogey

 


  • 0
    TI__Guru** 114905 points
    Hi Chen,

    The DRV8873-Q1 power can be calculated using equation 2 in the datasheet. For 2.3A through the TEC, the DRV8873-Q1 power should be ~1.64W using Rdson of 155mOhms for both the high side and low side FETs.

    Is anything else connected to VM that could account for additional power?
  • 0 in reply to Rick Duncan
    Mastermind 9990 points

    Hi Rick

    The customer use EVB to test, Just add LC(like DRV8412) in out side.

    there have no add other component.

    is there some set up we need to notice?

                                                 Bogey

  • 0 in reply to Chen Bogey8
    TI__Guru** 114905 points
    Hi Bogey,

    Is it possible the power supply reading is incorrect? I have had power supplies that report almost 100mA current with no load.

    Please check the power supply with no load and then again with load.

    There are additional current load around the board, such as a LDO, MCU, and LEDs. Those loads should not affect the reading significantly.
  • 0 in reply to Rick Duncan
    TI__Guru** 114905 points
    Hi Bogey,

    Do you have any additional information?
  • 0 in reply to Rick Duncan
    Mastermind 9990 points
    Hi Rick
    There is no problem in no load.

    when we connect TEC, then fault pin will be high, but we still can control DRV8873.
    For TEC feature,when flow current more high, TEC impendence will reduce.
    For last question, we still check power calculation issue. and why fault pin on when we connected TEC.
    Bogey
  • 0 in reply to Chen Bogey8
    TI__Guru** 114905 points
    Hi Chen,

    Sorry for the delay.

    Which device is this (DRV8873S-Q1 or DRV8873H-Q1)?
    Can you confirm the fault light is on? If it is on and the device is still driving current, this is probably one of the faults that does not disable the outputs (OLP, OLA, overtemperature warning). Please try isolating the fault by disabling the open load detection, current regulation reporting, or any others that help identify the fault.

    Please refer to Table 13 for details.
  • 0 in reply to Rick Duncan
    TI__Guru** 114905 points
    Hi Chen,

    We have not heard from you in some time, and are assuming your issue has been resolved. If it has not, please reply to this post or if the post is locked select "Ask a related question" at the top right of the window.