DRV8872: OUT leakage current

Yusuke Mukuno

Expert 7395 points

Part Number: DRV8872

Hi Expert,

My customer have same question with following E2E session,

And, they have additional question for it.

(your comment)

The picture on the first page shows OUT1 switching from high to high-z while the outputs are unloaded. During this time, the output can have some small leakage causing the voltage to be at ~5V. This can be confirmed by placing a 10kOhm to GND on the outputs.

OUT2 was at 0V when switching to high-z and did not experience the same leakage.

(Question)

Could you please let me know the maximum leakage value of output?

Thanks

Muk

over 3 years ago

0 Ryan Kehr over 3 years ago

TI__Guru 54665 points

Mukuno-san,

I will need to investigate this number. I will update the post when I have a response.

0 Yusuke Mukuno over 3 years ago in reply to Ryan Kehr

TI__Expert 7395 points

Ryan-san,

Do you have any update?

Thanks

Muk

0 Ryan Kehr over 3 years ago in reply to Yusuke Mukuno

TI__Guru 54665 points

Mukuno-san,

I am sorry, but I still do not have a response from design yet. Last week was Thanksgiving holiday, so many people were out. I have requested again.

0 Ryan Kehr over 3 years ago in reply to Ryan Kehr

TI__Guru 54665 points

Mukuno-san,

In the the first picture that customer shared from the datasheet, the part is operating for more time in Reverse mode (Brake decays current more slowly than compared to High-Z state). So, the coil current is moving from OUT2 to OUT1.

When device transitioned from the FORWARD mode to HIZ, current is still entering into the OUT1 node of the device.

This residual current passes through a zener path between the gate of the internal MOSFET and source. So current in this case, which holds OUT1 at ~6.5V(Vz+Vd), is the residual coil current itself flowing into the OUT1 node.

The maximum current that can flow thru this zener path is ~25mA. Any additional current will flow throw the body diode of the FET.

0 Yusuke Mukuno over 3 years ago in reply to Ryan Kehr

TI__Expert 7395 points

Ryan-san, Thank you for your answer!!

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DRV8872: OUT leakage current