DRV8231: Is Fast Decay going to rise the VM?

Kei Kuwahara

Part Number: DRV8231

Hello team,

I have read App note: Current Recirculation and Decay Modes.

And current is going to flow from GND to VM in Fast Decay mode.

I am assuming that the VM is going to rise because current is back flowing into VM (switching regulator).
Is my assumption correct?

If VM is going to rise when using Fast decay, is it going to damage the switching regulator of VM?
How can I protect it? Should I insert clamping diode between VM and GND?

Best Regards,
Kei Kuwahara

over 1 year ago

0 David Medis over 1 year ago

TI__Mastermind 19740 points

Hi Kei,

VM pumping, is what it's called when the motor voltage, VM, is pumped back to the supply. It is also referred to as motor regeneration, which is caused by regeneration of the motor during the deceleration process.

However, this will not occur while using Fast decay. In fact, Fast decay is actually one of the methods used to alleviate VM pumping.

Please see the following Technical Article that explains this process more fully:

Motor Drive forum Top FAQs Part 2: How to estimate motor regeneration and VM pumpi

Best,

David

Motor drivers

Motor drivers forum

DRV8231: Is Fast Decay going to rise the VM?