DRV8312 Current limit behaivour during motor startup (inrush current)

Janusz Debski

Other Parts Discussed in Thread: DRV8312, DRV8301, DRV8307

Hello,

I'm planning to use DRV8312 for BLDC motor application. Driver will work with various motors from 12 - 48V and max constant current 2.5A. Inrush current could be up to 10x higher then normal current 25A. Additionality one motor 12V has normal current of 3.41A and starting current 29.8A.
Inrush duration is aprox 10ms.

I would like to set OVC to 11-12A. Will DRV8312 work (in CBC mode) with 25A of inrush current 10ms? Is it possible also to work with 29.8A inrush to for 12V motor? How will motor startup looks like if DRV8312 works in CBC mode?

Motor spec

www.aviton.spb.ru/.../145.pdf

Thanks,

Janusz

over 10 years ago

0 Janusz Debski over 10 years ago

Prodigy 70 points

If previous link doesn't work:
www.maxonmotor.com/.../14-178-EN.pdf

0 Rick Duncan over 10 years ago in reply to Janusz Debski

TI__Guru** 114905 points

Hi Janusz,

If you are seeing transients of >20A, you may experience latched shutdowns during startup. Please note page 12 of the datasheet:

During short to power and short to ground conditions, since the current limit circuitry might not be able to control the current to a proper level, a second protection system triggers a latching shutdown, resulting in the related half bridge being set in the high-impedance (Hi-Z) state. Current limiting and overcurrent protection are independent for half-bridges A, B, and C, respectively

Also, setting the OC at 11-12 A for the DRV8312 may result in overtemp conditions.

Suggest you look at the DRV8301/2/3 or DRV8307/8 as an alternative. These are gate drivers and allow the external FETs to be sized for the 20+ Amps startup current.

0 Janusz Debski over 10 years ago in reply to Rick Duncan

Prodigy 70 points

Hi Rick

Thank you for your answer and proposition.

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DRV8312 Current limit behaivour during motor startup (inrush current)