TI中文支持网Part Number:DRV8701
Hi TI team,
We've designed a motor circuit recently, something very crazy is that it may work or get short circuit on different PCBs with the same schematic and layout.
Details here:
The power supply is shorted without motor loading, it seems like the High fet and the low fet at the same side are working at the same time.
When the duty of the signal PWM is very low like 1%~2%, it is working normally, we can test that the drive signal for MOSFET are right, when the duty gets larger, problems happen like above. And the drive signal for MOSFET become chaos and we can't test it.
We get two same circuit on one PCB, they are only diffrent on the layout.
And here are our schematic and layout, in this version, it dosen't work.
In this version, it works perfectly.
We used a 5v signal to the nSLEEP pin.
We have been confused by this question for a really long time.
We sincerely hope some guide from you, thanks so much.
? ?：
Oh something I forgot to write, that without the PWM Input, the circuit doesn't get shorted.
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Annie Liu：
Sorry for the late reply due to the Dragon Boat Festival holiday.
I think the issue is that IDRIVE is connected to GND via C41 (1uF). This will cause improper reading of the resistance on the IDRIVE pin to GND which determines the IDRIVE to use.
To resolve the issue, remove C41 and C40 and connect IDRIVE to directly to GND or a resistor to GND depending on the desired sink and source current from the table below. Add C41 and C40 to AVDD instead as recommended by the datasheet.
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? ?：
Thank you so much for your reply! Last two days we tried to remove the C40 and it worked some times.
We will try the method as what you said as soon as possible. And we will give you the feedback once we test it.
And we are really graceful for your support.
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Annie Liu：
Ok, looking forward to your good results.
