DRV8243-Q1: Back-EMF protection of motor controller

Ole Anders Riiser

Part Number: DRV8243-Q1

Tool/software:

We want to use this motor for a bi-diretional dc motor application and want to make sure we handle back EMF issues. This driver seems to go into Hi-Z mode when sleeping and turned off. Are there any way of achieving brake mode or other similar protection methods while using this driver?

3 months ago

0 Shinya Morita 2 months ago

TI__Mastermind 44315 points

Hi,

Thank you for your questions.

Main concern is thermal. Based on current level and duration, we can estimate Ploss by Diode path during HiZ. Rtheta j-a by duration is available on datasheet.

regards

Shinya

0 Ole Anders Riiser 2 months ago in reply to Shinya Morita

Prodigy 20 points

Thanks for the reply Shinya. I did not see this diagram before i posted the question. Will this be the current path of the EMF in HIZ mode(depending on direction)? What is the characteristics of R-HIZ?

0 Shinya Morita 2 months ago in reply to Ole Anders Riiser

TI__Mastermind 44315 points

Thank you for your questions.

What I meant is following sequence. Left side is spinning motor with motor current. If H-Bridge changes to HiZ state, motor current keep flowing with Diode path like right side of picture. It will continue until the charged energy in motor will be zero.

RiZ is not main portion of thermal/Ploss.

regards

Shinya

0 Ole Anders Riiser 2 months ago in reply to Shinya Morita

Prodigy 20 points

Hello.

That would then send energy into VM if force is applied to the wheel, and may harm other electronics in the circuit? I would like to have a way of going into "brake mode" so the terminals of the motor is shorted either to high side or low side.

0 Shinya Morita 2 months ago in reply to Ole Anders Riiser

TI__Mastermind 44315 points

Hi,

Thank you for your questions. Will provide feedback in 2-3days

regards

Shinya

+1 Shinya Morita 2 months ago in reply to Shinya Morita

TI__Mastermind 44315 points

Hi,

Each mode (PH/EN, PWM. Independent) has braking mode by IN1/IN2 pins. Here is example in PWM mode.

regards

Shinya

0 Ole Anders Riiser 2 months ago in reply to Shinya Morita

Prodigy 20 points

Thanks alot Morita. I also would like to enter this mode whenever the motor starts spinning and external power is off. do You know of any application notes regarding this? I guess you could have a pull-up to VM to handle this or something similar

0 Shinya Morita 2 months ago in reply to Ole Anders Riiser

TI__Mastermind 44315 points

Hi Thank you for your questions. Will feedback to you ilater

0 Shinya Morita 2 months ago in reply to Shinya Morita

TI__Mastermind 44315 points

Hi,

If you set nSLEE=High, DRVOFF=Low, IN1/IN2=Low in PWM mode, OUTPUT will be H/H.

Please generate new post if you have further questions

regards

Shinya Morita

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DRV8243-Q1: Back-EMF protection of motor controller