DRV8323: CPUV and GDF Error at 200A Phase Current

Martin Fuchs7

Part Number: DRV8323
Other Parts Discussed in Thread: TIDA-00774, TP120

Hi,

I have problem with the DRV8323 in my battery powered drill design. When the electronics reach 200A Phase current, the DRV reports errors. Most of the time the CPUV together with the GDF error of a high side. Do these 2 errors correspondent together => the charge pump undervoltage cause the “not” switching of the high-side?

I changed the tdrive time and the idrive current of the High-side (both to maximum), but it makes no difference.

Another question is, what can I change on the external components of the driver to improve the charge pump voltage stability? In you TIDA-00774 reference design, you only use 22nF for the CPH, CPL capacitor.

Or do I have to increase the input capacity of VM?

Kind regards

Martin

over 4 years ago

0 Adam Sidelsky over 4 years ago

TI__Guru 61380 points

Martin,

Could you show us some scope images of TP120 and the differential Vgs of the HS FETs when the fault occurs?

This could help us understand the issue more.

Regards,

-Adam

0 Martin Fuchs7 over 4 years ago in reply to Adam Sidelsky

Intellectual 255 points

Hi Adam,

I only could take a picture of the TP120 (green), VM (yellow), DRIVER_FAULT (blue) and Phase current (red)

I also have a picture where the yellow graph is the phase voltage of the current measured phase

Could this a problem, that my DC_Link voltage jumps over the Charge Pump voltage after a commutation?

Rgds Martin

0 Martin Fuchs7 over 4 years ago in reply to Martin Fuchs7

Intellectual 255 points

Here the pictures, they were deleted after reply.

The one with the VM voltage:

The one with the Phase voltage:

0 Adam Sidelsky over 4 years ago in reply to Martin Fuchs7

TI__Guru 61380 points

Martin,

I see both your VM and CP voltages are decreasing significantly when the phase current is high. Do you have any additional bulk capacitance near the VM pin of the DRV? What about bulk capacitance near the FETs?

Regards,

-Adam

0 Martin Fuchs7 over 4 years ago in reply to Adam Sidelsky

Intellectual 255 points

Hi Adam,

On VM I only have the recommended 10µ + 100n. Near the FET's I have 660µ electrolytic + 13.2µ ceramic capacitors.

Rgds, Martin

0 Adam Sidelsky over 4 years ago in reply to Martin Fuchs7

TI__Guru 61380 points

Martin,

Can you share the FET section of your schematic and the complete layout?

Regards,

-Adam

0 Martin Fuchs7 over 4 years ago in reply to Adam Sidelsky

Intellectual 255 points

Hi Adam,

I can't share these information in an open forum.

Regards, Martin

0 Adam Sidelsky over 4 years ago in reply to Martin Fuchs7

TI__Guru 61380 points

Martin,

Please email me in that case.

adamsidelsky(at)ti(dot)com

Regards,

-Adam

0 Martin Fuchs7 over 4 years ago in reply to Adam Sidelsky

Intellectual 255 points

Hi Adam,

In the meantime I found the problem caused the CPUV errors. In front of the capacitors C5 and C6 are two resistors to limit the inrush current. That’s necessary, because we switch this voltage “Akku_Power_geschalten” with a Mosfet.

Now, I have removed the resistor an assemble a Mosfet with a better pulse current specification (45A needed). Afterwards I don’t have any fault in the driver.

Regards, Martin

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DRV8323: CPUV and GDF Error at 200A Phase Current