UCC21750: DESAT protection

abhishek deshmukh

Part Number: UCC21750

Hi,

I come across the following DESAT protection link on e2e.ti.com forum.

[FAQ] UCC21750: How can we Increase DESAT Charging current for faster Short-circuit detection time in UCC217xx and ISO5x5x? - Power management forum - Power management - TI E2E support forums

A the end below matlab solution on above link, there is equation 8 as below -

Here, what is the base of the logarithm? Is it natural log at base e or common logarithm at base 10??

Regards,

Abhishek D.

over 1 year ago

+1 Sasikala Thangam over 1 year ago

TI__Expert 6000 points

Hi Abhishek,

Thanks for your interest on UCC21750

Its natural log at base e.

Thanks

Sasi

0 abhishek deshmukh over 1 year ago in reply to Sasikala Thangam

Prodigy 220 points

Hi Sasi,

We are implementing DSAT protection with UCC21750-Q1 driver as in below snap -

Here, the OUTH pin is connected to a resistor R121 & DESAT pin connected to R123 & C82. C82 is blanking capacitor, In order to prevent false triggering, the blanking cap value selected as 1000pF. D6 is the ultrafast diode with 1000V rating connected to drains of MOSFET full bridge & blocks 700V at MOSFET drain.

This configuration is done to effectively have DESAT protection as mentioned in below link -

[FAQ] UCC21750: How can we Increase DESAT Charging current for faster Short-circuit detection time in UCC217xx and ISO5x5x? - Power management forum - Power management - TI E2E support forums

With this configuration, will there be any issue? Any suggestion for further improvement or this is sufficient?

Regards,

Abhishek

0 Richard Herring over 1 year ago in reply to abhishek deshmukh

TI__Mastermind 21305 points

Hello Abhishek,

Sasi is out of the office at the moment but will address your question within the next business day.

Regards,

+1 Sasikala Thangam over 1 year ago in reply to Richard Herring

TI__Expert 6000 points

Thanks Richard for your support.

Hi Abhishek,

Overall it looks good. Can you please share what is the system voltage, how much is the DESAT blanking time you would like to achieve and what is the threshold voltage at the Drain you want to detect.

I believe you have considered all these in your component selection.

If you are not comfortable sharing the details in the open forum, we can continue the conversation in the email thread and close this ticket. I will share you my email

Thanks

Sasi

0 abhishek deshmukh over 1 year ago in reply to Sasikala Thangam

Prodigy 220 points

Hi Sasi,

Thanks for confirming.

Mail sent to you.

Regards,

Abhishek