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DRV8412 - Drive TEC

Jimmy ROUX
Prodigy 40 points
Other Parts Discussed in Thread: DRV8412

Hi,

I am looking to use DRV8412 chip to drive a TEC for both heating and cooling operations

Referring to the figure 17 (page 22) in the datasheet, there is two PWM signals that might drive two half bridges, so we should have typically 4 possible cases like below :

PWM A/B = 1 & PWM C/D = 0 => forward, TEC is cooling (for example)

PWM A/B = 0 & PWM C/D = 1 => reverse, TEC is heating (for example)

PWM A/B = 0 & PWM C/D = 0 => slow decay (is it necessary with TEC by the way or fast decay is acceptable ? Even with LC filter as suggested ?)

PWM A/B = 1 & PWM C/D = 1 => useless

Is that true ?

  • 0
    TI__Guru** 114905 points

    Hi Jimmy,

    jimmy rouc said:

    Referring to the figure 17 (page 22) in the datasheet, there is two PWM signals that might drive two half bridges, so we should have typically 4 possible cases like below :

    PWM A/B = 1 & PWM C/D = 0 => forward, TEC is cooling (for example)

    PWM A/B = 0 & PWM C/D = 1 => reverse, TEC is heating (for example)

    PWM A/B = 0 & PWM C/D = 0 => slow decay (is it necessary with TEC by the way or fast decay is acceptable ? Even with LC filter as suggested ?)

    PWM A/B = 1 & PWM C/D = 1 => useless

    Is that true ?

    Basically this is true, although PWM A/B = 1 & PWM C/D = 1 can also be used for slow decay, but not indefinitely.

    Slow decay allows the current ripple to be minimized. It should be considered if you are PWM'ing the outputs to maintain a desired current level. It you are running 100%, it may not matter.