UCC21710-Q1: Blank time measurement for desat protection

Ganesh K

Part Number: UCC21710-Q1

Hello team,

I have following questions regarding blank time measurement.

Please mark the blank time duration in the below wave form which is not mentioned in datasheet

2. I have attached my simulation results in which the blanking time is not matching with the calculated blank time(339.12ns). Please help me to calculate the proper blank time.

10 months ago

0 Sean Cashin 10 months ago

TI__Genius 17666 points

Hi Ganesh,

1. The blanking time is labeled "t_ocfil" in this Figure 7-10. It is the amount of time needed to charge the low-pass filter formed by R_flt and C_flt above V_octh.

2. The time will depend on how high the Vds is above 0.7V. The filter is there to prevent noise from creating a fault, not to create a strictly constant blanking time. In addition, there seems to be a period of time between the Vgs rise and the start of the V(oc) charging. I don't know how accurate this duration is in the model. I am currently working on a model refresh and will get back to you if I get a different result with the new model.

Best regards,

Sean

0 Ganesh K 10 months ago in reply to Sean Cashin

Prodigy 30 points

Thanks for the reply. If t_ocfil is the blanking time then I have taken the below image from an excel in which blanking time is different. I noted another one thing that OC pin has 6V during the gate pulse reaches steady state if the pin left open (Image also attached for this).

Hope you will share the good model as soon as possible

...

0 Sean Cashin 10 months ago in reply to Ganesh K

TI__Genius 17666 points

Hi Ganesh, I am working on it right now.

0 Sean Cashin 10 months ago in reply to Ganesh K

TI__Genius 17666 points

Hi Ganesh,

I have a first draft. Here is the .lib file and the schematic configuration you can use for a quick start. I am still verifying all of the correct behavior of the design.

Best regards,

SeanUCC21750.lib

0 Ganesh K 9 months ago in reply to Sean Cashin

Prodigy 30 points

Thanks

0 Sean Cashin 9 months ago in reply to Ganesh K

TI__Genius 17666 points

Hi Ganesh,

If you have any feedback, please reply to this thread. I have made a few edits and here is an updated version: 2477.UCC21750.lib

Best regards,

Sean

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UCC21710-Q1: Blank time measurement for desat protection