DRV8313: Min On time of PWM

Hirokazu Takahashi

Expert 8420 points

Part Number: DRV8313
Other Parts Discussed in Thread: DRV8312

Dear Support team,

Could you let me know the min on time of PWM pulse?

Best Regards,
Hirokazu Takahashi

over 5 years ago

0 Adam Sidelsky over 5 years ago

TI__Guru 65370 points

Takahashi-San,

Please let me check this and get back to you.

Regards,

-Adam

0 Hirokazu Takahashi over 5 years ago in reply to Adam Sidelsky

TI__Expert 8420 points

Hello Adam-san

I haven't gotten any proper answer from you yet.
It passed over 10 days until now.
Could you please response ASAP?

Best Regards,
Hirokazu Takahashi

0 Adam Sidelsky over 5 years ago in reply to Hirokazu Takahashi

TI__Guru 65370 points

Takahashi-San,

I need to measure this and I do not have an EVM in hand so I have ordered one, please allow me a few days to receive the board and test this.

Regards,

-Adam

0 Hirokazu Takahashi over 5 years ago in reply to Adam Sidelsky

TI__Expert 8420 points

Hello Adam-san

Thanks for your reply. I'll wait for your response regarding min on time.

I have one more question of DRV8313/12.
Could you let me know the min/max value of output dead time of DRV8313 and 12?

Best Regards,
Hirokazu Takahashi

0 Hirokazu Takahashi over 5 years ago in reply to Hirokazu Takahashi

TI__Expert 8420 points

Hello Adam-san

I haven't gotten any response yet.
Could you please support my inquiries?

Best Regards,
Hirokazu Takahashi

0 Aaron Barrera over 5 years ago

TI__Mastermind 26046 points

Hi Hirokazu,

Adam and I measured on a DRV8313 EVM the min on time of a PWM pulse to be 200ns in order to see a positive width pulse on an output pin.

For a PWM frequency of 20kHz, this equates to a duty cycle of 0.41%.

For a PWM frequency of 40kHz, this equated to a duty cycle of 0.82%

We will get back to you later today in regards to min/max value of output dead time of DRV8313 and DRV8312.

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

TI__Mastermind 26046 points

Hi Hirokazu,

I have measured the dead time to be about 75 ns. Because the DRV8313 is an integrated MOSFET device, the best approximation of measuring the dead time of the device is by measuring the body voltage drop on the phase nodes of OUT1 and OUT2. The body diode experiences a -0.7V drop when current is being sourced from ground and through the body diode during the dead time period of the switching event (GHX and GLx are off), so this equates to the dead time of the internal MOSFETs.

I have attached a couple of oscilloscope screenshots below of OUT1 (yellow) and OUT2 (pink), both showing a -0.7V magnitude of about 75 ns.

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DRV8313: Min On time of PWM