DRV8306: duty cycle resolution

EE Guy

Part Number: DRV8306

Hi, What is the duty cycle resolution for the PWM control input to the DRV8306? So for example if I have a PWM at 20kHz and I adjust the duty cycle from 50% to 50.01%, will the commanded speed change? Thanks.

over 5 years ago

0 Adam Sidelsky over 5 years ago

TI__Guru 65450 points

Gabe,

Let me check on this for you and get back to you. The increment will be time based so if you double the frequency then the same duty cycle change would cause a smaller increment in effective ON time.

Regards,

-Adam

0 Aaron Barrera over 5 years ago in reply to Adam Sidelsky

TI__Mastermind 26046 points

Hi Gabe,

I checked the duty cycle resolution using a DRV8306-EVM and sending a 20kHz PWM signal to the PWM pin.

I was able to see noticeable changes in the effective ON time for a 0.01% resolution. You may be able to get finer resolutions than 0.01%, but was limited to the resolution of the waveform generator.

0 EE Guy over 5 years ago in reply to Aaron Barrera

Intellectual 280 points

Hi Aaron, Thanks for the quick response. I'd like to dig a bit deeper. I'm assuming there is a DAC inside this thing that processes this incoming PWM symbol. If that's the case, how many bits resolution does the DAC have?

0 Aaron Barrera over 5 years ago in reply to EE Guy

TI__Mastermind 26046 points

Hi Gabe,

There is not a DAC inside the DRV8306. The input PWM is comparator-based and sends the comparator signal to internal logic. Overall, the DRV8306 control logic produces the gate driver voltages.

Motor drivers

Motor drivers forum

DRV8306: duty cycle resolution