DRV8301 PWM input questions

Edward Averill

Other Parts Discussed in Thread: DRV8301

I'm a DRV newbie, so here are some clueless questions:

- I'm sweeping the PWM inputs from 0 to 100% duty cycle as az test (no motor connected) - shouldn't I see the voltage sweep up and down on at lest one of the 3 outputs? All I see is a static output equal to my input voltage

- Is there an optimal PWM period to use with the DRV8301?

I'll re-red the data sheet, but all info, manual refs, etc. appreciated!

Ed Averill

over 11 years ago

0 Nicholas Oborny over 11 years ago

TI__Mastermind 21320 points

Hi Ed.

What mode are you in, 3PWM or 6PWM. In 6 PWM you must provide the inverse signal as well.

Ensure EN_GATE is high.

The DRV8301 will switch the output from low to high and vice versa. 0V -> PVDD. The duty cycle and frequency will depend on the PWM inputs.

What frequency are you switching at? Motor usually switch anywhere from 20kHz to 50kHz. The DRV8301 can support 0Hz to 200kHz.

0 Edward Averill over 11 years ago in reply to Nicholas Oborny

Genius 3100 points

It's in default 6 PWM mode.. I guess I don't understand motor control well enough.. Google should save me! I was feeding in slightly different PWMs in the HIGH/LOW slots.. inverse, nope, so there's one issue.

The period is around 35KHz, but I think I've identified my issue here... lack of knowledge on my part!

Does TI have any good learning resources for motor control? I'll start with Google...

Again, thanks a TON for educating me!

Ed Averill

0 Nicholas Oborny over 11 years ago in reply to Edward Averill

TI__Mastermind 21320 points

Ed,

You will find tons of resources on the web. Please see the following link that will take you to information on BLDC solutions from TI:

http://www.ti.com/solution/motor_control_brushless_dc#Application

You can also just type in www.ti.com/motors to find other resources.

0 Edward Averill over 11 years ago in reply to Nicholas Oborny

Genius 3100 points

Thanks! I'm going to spend the rest of the week doing research and figuring out what I need to throw together something to hook up to the DRV boost board and my MSP430.

Have a great rest of the week and a good weekend!

Ed Averill

0 Rick Duncan over 11 years ago in reply to Edward Averill

TI__Guru** 114905 points

Hi Ed,

Another application note available is http://www.ti.com/lit/an/slaa503/slaa503.pdf.

This was written by the MSP430 group.

0 Edward Averill over 11 years ago in reply to Rick Duncan

Genius 3100 points

Wow, excellent! You guys are great!

This is why I recommended TI silicon for this project - the excellent level of support. When I was working at Danger on the Sidekick, and at Palm on the Pre and Pixi, TIs support was uniformly great.

Time for some serious research and the purchase of a small BLDC motor to prototype with.

Again, thanks!

Ed Averill

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DRV8301 PWM input questions