DRV2667: No output signal is generated 2

Maxim Raznatovski

Part Number: DRV2667

Hello,

I am still waiting for a response (since 5 weeks!) about my issue (https://e2e.ti.com/support/motor-drivers/f/38/t/915224).

Since then I tried following things:

* decrease the boost voltage to 50V

* Attach capacitors to IN+ and IN-

* use various power supplies for VDD and REG

* Solder 5 different ICs/PCBs

* measure and compare every pin to the datasheet

* shorten the distance between FB and the two resisters

* analyse all I2C data with a logic analyzer

* use 2 platforms to send the I2C commands (ESP32 and Arduino UNO)

Best regards,

Maxim Raznatovski

over 3 years ago

0 Luis Fernando Rodriguez S. over 3 years ago

TI__Guru* 84915 points

Hi, Maxim,

For some reason I didn't get the notifications of your previous replies.Thank you for posting your issue again so we can properly follow up this case.

I have some questions regarding your application.

- Have you tested a different device configuration like the one showed in section 8.3.2.2? Or could you try increasing the number of cycles in your current example from 5 to 20 or more?

- Could you also start your configuration with the command "write_to_drv2667(0xFF, 0x00)"?

Please let me know any observation you have with these tests.

Best regards,
Luis Fernando Rodríguez S.

0 Maxim Raznatovski over 3 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 90 points

Hello, Luis,

Unfortunately adding "write_to_drv2667(0xFF, 0x00)" is not changing my results.

Changing the number of cycles is also not helping.

Additionally I just tried running the second example with the same result.

Best regards,

Maxim Raznatovski

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Maxim Raznatovski

TI__Guru* 84915 points

Hello, Maxim,

Have you compared your results with our DRV2667EVM? Have you ordered one of these in order to use it under the same test conditions?

Best regards,
Luis Fernando Rodríguez S.

0 Maxim Raznatovski over 3 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 90 points

Hello, Luis,

No, I have not ordered the EVM Board and probably will not, since I found the problem (maybe?).

If I increase R4 (The GND resistor to REXT) from 13kOhm to 30kOhm, the board is functional with up to 150vpp (around 75v on BST).

But changing the resistor to 20, 25 or 27kOhm does still not work (the used inductor supports up to 1.4A sat current).

Is it possible that my VCC or GND trace is too thin? It would be great to get 200vpp running. but 150vpp is also not bad.

Did somebody experience a similar issue?

Best regards,

Maxim Raznatovski

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Maxim Raznatovski

TI__Guru* 84915 points

Hi, Maxim,

Thank you for the information you provided. Have you gotten more results these weeks?

Have you tested your circuit with a different inductor with higher current capabilities to see if the problem is associated to it?

It seems that the inductor current cannot be higher than 0.5A based on the Rext resistor you are using. Does your power supply is limited to a lower current?

Best regards,
Luis Fernando Rodríguez S.

0 Maxim Raznatovski over 3 years ago in reply to Luis Fernando Rodriguez S.

Prodigy 90 points

Hello, Luis,

I am using the SRN3015TA-3R3M Inductor from Bourns which should
support a saturation current of 1.4 A. As a power source I use a Lab bench power supply (up to 5 amps).
I have not tried replacing the inductor yet
but some time later I will order a next revision of the PCB. If is still have problems, I can try a different Inductor.

Now I am getting around 180vpp.

Best regards,
Maxim Raznatovski

0 Luis Fernando Rodriguez S. over 3 years ago in reply to Maxim Raznatovski

TI__Guru* 84915 points

Hi, Maxim,

Thank you for your update, please let us know any feedback you have regarding the next PCB version and inductor once you have the results.

Best regards,
Luis Fernando Rodríguez S.

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DRV2667: No output signal is generated 2