DRV8873: Body diode current.

Ed Eeltink

Part Number: DRV8873

What is the maximum allowed continuous current through the body diodes of the output FETs.
It is not mentioned in the datasheet.
Only a voltage at 1A is given.

over 3 years ago

0 Pablo Armet over 3 years ago

TI__Mastermind 37683 points

Hi Ed,

The DRV8873 can handle up to 10-A peak before the device shutsdown due to over-current protection. As for the maximum continuous current, this will be limited by the PCB design. If there isn't enough PCB copper tied to the thermal GND pad or enough heatsinking to dissipate the heat, the device can go into temperature shutdown due to the high power dissipation. The following resources provide more information on IC thermal metrics and power calculations:

0 Ed Eeltink over 3 years ago in reply to Pablo Armet

Prodigy 10 points

Yes, the device can handle 10A via the FET, but can I assume the body diode is able to handle this current too?
I expect it can, but nothing tells me it is safe to do.
Suppose a motor connected to this device is mechanically driven by an external force. It will act as generator and force current via the body diodes into the power supply. The thermal protection does nothing to prevent that. Either external diodes that can handle the maximum expected current or the internal body diodes must pass this current. External (schottky) diodes are a safe solution but require board space and add cost.

+1 Pablo Armet over 3 years ago in reply to Ed Eeltink

TI__Mastermind 37683 points

Hi Ed,

Ed Eeltink said:
Yes, the device can handle 10A via the FET, but can I assume the body diode is able to handle this current too?

That's correct. The body diodes are rated to withstand 10-A plus a few more Amps of peak current for margin.

Ed Eeltink said:
Suppose a motor connected to this device is mechanically driven by an external force. It will act as generator and force current via the body diodes into the power supply. The thermal protection does nothing to prevent that.

The energy generated by the motor will flow back to the power supply through the body diodes of the FETs. The main concern when a motor is driven externally is the voltage rise on the power supply. The voltage can increase above the safe operating limits of the driver. One way to protect against it is to add a schottky diode on the main power supply.

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DRV8873: Body diode current.