DRV8313: Determining H-Bridge Efficiency/Losses

Aram Dergevorkian

Part Number: DRV8313

Hi,

I'm trying to determine the power dissipated in a pair of these ICs I'm using to drive a stepper motor. The datasheet provides some information that would be useful with a purely resistive load, however, each coil is about 33Ω and 29mH making things more complicated.

My first thought was to model my circuit with this part, but there isn't a SPICE model of this part (I have checked with TI support). A simulation constructed from discrete generic FETs might work, but I don't know if I have enough information to model the internal gate drivers and FETs representatively.

Any suggestions on determining the losses analytically?

Thanks!

over 3 years ago

0 Adam Sidelsky over 3 years ago

TI__Guru 61360 points

Aram,

The datasheet shows how to calculate this in section 10.4 Power Dissipation and mentions RDSON which is listed in the electrical table. All you need is the average output current.

Regards,

-Adam

0 Aram Dergevorkian over 3 years ago in reply to Adam Sidelsky

Prodigy 35 points

Hi Adam,

I saw this in the datasheet, but was concerned that this oversimplified the switching characteristics to some extent.

I hesitate to look at the outputs as transitionless resistive switches. If you're saying that the gate drivers are robust enough for this to be assumed given my use case, then I'll look at it as a slightly generous approximation.

Thanks,
Aram

0 Adam Sidelsky over 3 years ago in reply to Aram Dergevorkian

TI__Guru 61360 points

Aram,

The information I have provided you above is the best we have and should be accurate. If you have another question, please let me know.

Regards,

-Adam

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DRV8313: Determining H-Bridge Efficiency/Losses