DRV8701: ERGRE

Katherine Wang

Part Number: DRV8701

Hi Team,

On the schematic, the VM, with a voltage input of 40V, was to drive an 800W motor. When the load was connected to drive the motor, the chip turned very hot and burnt out immediately. Why did the chip burn out? In the cases of EN pin PWM control as well as gpio control, the chip burnt out directly.

Kind regards,

Katherine

over 2 years ago

0 Ryan Kehr over 2 years ago

TI__Guru 55605 points

Katherine,

I suspect the voltage on VM may be exceeded specification of the device when driving the motor. Is there a way to test the board at a lower voltage like 24V initially?

Also, I see no decoupling on the VM pin. There should be a small capacitor to GND (ceramic) plus a bulk capacitor in the range of 10uF. Finally, there should be some bulk capacitors near the outputs FETs from the DRAIN of each high-side FET to GND. I don't see those either. Without proper decoupling, the supply can be swinging quite a bit when driving a motor.

Regards,

Ryan

0 Katherine Wang over 2 years ago in reply to Ryan Kehr

TI__Intellectual 2210 points

Hi Ryan,

After I connected the capacitor, I could drive the motor. I have a new query. When driving the motor, the waveform of VM is not right. Why does the voltage increase (to about 48V)?

Regards,

Katherine

0 Ryan Kehr over 2 years ago in reply to Katherine Wang

TI__Guru 55605 points

Katherine,

Please read this blog:

https://e2e.ti.com/blogs_/b/industrial_strength/posts/art-of-stopping-the-motor-vm-pumping

Regards,

Ryan

Motor drivers

Motor drivers forum

DRV8701: ERGRE