drv2605L problem driving ERM (overcurrent)

Sasa Milovanovic

Prodigy 30 points

Other Parts Discussed in Thread: DRV2605L

Hi!

I am having trouble driving two ERM vibration motors:

This one
And this one

Overcurrent bit appears to be set.

I am trying to drive them in open-loop mode. Rated voltage and overdrive clamp are correctly set.

This and this ERM works fine.

Thank you in advance.

Best regards!

over 7 years ago

0 JP over 7 years ago

TI__Expert 3200 points

Hello Sasa,

Unfortunately the links you provided are not working correctly, can you please update the post with working links?

Best Regards,

Javier Palomo

0 Sasa Milovanovic over 7 years ago in reply to JP

Prodigy 30 points

Hi!

Sorry for the bad links...

These are the working ones:
www.precisionmicrodrives.com/.../20mm-vibration-motor-25mm-type-0
www.precisionmicrodrives.com/.../312-108-12mm-vibration-motor-3mm-type

And here are overcurrent ones:
www.precisionmicrodrives.com/.../310-002-10mm-vibration-motor-15mm-type
www.precisionmicrodrives.com/.../307-002-7mm-vibration-motor-17mm-type

Thank you!

0 JP over 7 years ago in reply to Sasa Milovanovic

TI__Expert 3200 points

No worries, and thank you for the updated links. I will look into this and get back to you.

Best Regards,
Javier Palomo

0 JP over 7 years ago in reply to Sasa Milovanovic

TI__Expert 3200 points

Sasa,

The DRV2605L's overcurrent protection is triggered once the impedance across the output is too low ( ≈ 4 Ohms) to prevent a short circuit.

After looking at the actuators specifications, it appears that the ERM's triggering the Overcurrent bit both have an impedance below 1.5 Ohms. Can you measure the resistance across the ERM's to verify this?

Best Regards,
Javier Palomo

0 Sasa Milovanovic over 7 years ago in reply to JP

Prodigy 30 points

Well, you are absolutely right. Impedance is slightly lower than 4ohms.

In detail:

Smallest ERM has large resistance, and there is no problem with it. Largest motor has impedance around 4.5ohm, and every once in a while it raises OC bit. Other two motors have impedance below 4ohm, and they won't even start.

I guess we have to choose another ERM with better parameters.

Thank you so much for your help!

Best regards!

0 JP over 7 years ago in reply to Sasa Milovanovic

TI__Expert 3200 points

Happy to help, and let us know if there is anything else we can help you with!

Best Regards,
Javier Palomo

0 Takumi Suzuki1 over 7 years ago in reply to JP

Mastermind 8420 points

Hi Javier-san,
Let me confirm the current.
I suppose the overcurrent protection value is around 1.3A (4ohm/5.2V:VDD), correct?
0.65A (8ohm/5.2V) is within apecification, right?

Thanks!

0 Kelly Griffin over 7 years ago in reply to Takumi Suzuki1

TI__Expert 8691 points

Hi Takumi-san,

Yes, 8ohms is within the specification.

0 Takumi Suzuki1 over 7 years ago in reply to Kelly Griffin

Mastermind 8420 points

Thank you Kelly-san!
I understood.
Regards,

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drv2605L problem driving ERM (overcurrent)