DRV8812 slow decay seems not work - update

Hi Jose

Thank you for the answer.
Unfortunately there is no work-around (we can't PWMing PHASE), so the only solution is to replace DRV8812 by DRV8814 (I discovered it just yesterday on TI site) since we have 10 prototypes that must absolutely be running within 24/11 (our customer has an important demo on 26/11...)

We need 30 pcs. of DRV8814PWPR, but samples are not available fromTI site: should you kindly get us these samples by DHL or any very quick carrier? In case of need for any further information you can refer to Mr. Malfer or Bagarelli from Siverstar/Arrow group Milan, our distributor and support for this design (they are both complete knowledge of the problem).
If  this is possible, please send us the samples to following address:

NETTRONiX S.r.l.
Att.n Mr. Maurizio Canton
Via dei Novelli, 28
23899 ROBBIATE (LC) - ITALY

If instead this was not possible, please send samples to SIlverstar to the att.n of Mr. Malfer or Bagarelli.

Thank you very much, best regards

Maurizio

Hi Maurizio,

I am procuring the samples and we will try to ship as soon as possible.

It is a possibility we will not be able to ship directly to an address that is not a TI address. If so, who would the closest TI representative be? We will definitely shoot to get you these samples before November 26, 2010.

Best regards,

JIQ

Jose, Maurizio -

It looks from your address that you are quite close to our Milan office, which is in Vimercate.  Is that correct?

If so we , it should be fastest to send the parts to our office there.  We can probably arrange to bring them to your location.   I will also check to see if by any chance they already have some parts at the office there.

Sorry again for the trouble...

Hi Maurizio,

We are studying we can ship directly to you or to one of our sales representative in the region. Could you send me your telephone number to my email jquinones@ti.com?

I think we can close this matter and required shipping details outside of the forum. Thanks!

Best regards,

JIQ

Pete, Jose

It's correct, Vimercate is close to our offices.
If you can send the devices to your office in Vimercate we will go there to take them, there is no need that your colleagues bring them to us.

For any communication, they can contact me to following mobile #:

Maurizio Canton
(+39) 349 0785814

Thank you very much for your kindness and promptness.

Best regards

Maurizio

Hi Jose

I wrote you at the e-mail address you indicated me, but I still haven't received an answer: did you received my e-mail?

Best regards

Maurizio

Hi Maurizio,

Do not recall receiving a message to my email, but the parts were shipped from my office the very same date we had this discussion. It just takes quite a bit of time to clear our shipping department. Hopefully you get then in time. You may want to check with Ivan Dal Santo at the Italy office. Sorry for the delay.

Best regards,

JIQ

Does this problem also occur in the DRV8828? also when would we be able to start to buy the DRV8814?  

Thanks

Greg

Hi Greg,

The behavior of not being able to BRAKE a DC motor while using the DRV8812 device will also be present on the DRV8828. I understand this is a problem for applications trying to drive DC motors, but what we must understand is that this is a feature highly desired for stepper motor driving.

If the slow decay mode was engaged even after enable is de-asserted, as expected on a device intended for DC motor driving with BRAKE, then the stepper motor would be on slow decay at all times after disablement. This would place the windings under close to short circuit constraints which in turn will account for an increased torque requirement to move the shaft. In other words, the shaft will not move freely as easy as if the motor windings were completely floating, as is obtained by allowing the motor to remain on asynchronous fast decay. 

In order to meet all of our customer's needs, we are building respective DC motor counterparts. That is a device which is basically identical, except that the BRAKE function is put in place.

Following this guideline, we have re-defined the DRV8812/13/28/29 solely as stepper drivers. You can still use them to drive DC motors as long as the BRAKING function, or ENABLE PWM is not needed. If PHASE PWM is utilized to drive the motor, as in most servo application, the device will work perfectly.

The DRV8814, the counterpart to DRV8813, will be released to manufacturing later on this quarter. At the same time, DRV8840 will be released which is the counterpart for the DRV8829. That is, DRV8829 is a single H Bridge with 5A capabilities but no BRAKING. DRV8840 is the exact same device, but with BRAKING capabilities.

Hope the info helps. Let me know if there is anything else I can help you with. Best regards,

JIQ

Hi Jose,

I work locally with Greg. Greg required some DRV8812 samples. Will you now be able to provide any preliminary DRV8802 or DRV8814 silicon that can be used instead?

Thanks,

We can take this discussion offline if required.

Hi Leslie,

We have DRV8814 samples we can supply. Please contact me at jquinones@ti.com and we will set this up. Thanks!

Best regards,

JIQ

Thanks for your help.  When is the DRV8814 going into production so I can see if it will work with our product's release?

Thanks

Greg

Hi Greg,

The DRV8814 is scheduled to be released into manufacturing in between the very end of March and early April. I will work with Leslie to make sure we can help your design efforts.

Best regards,

JIQ