UCC21750: Combination of UCC21750 and SiC-MOSFET

Hi,

While it is possible to use the DESAT feature for short-circuit protection, the OC (overcurrent) feature of other gate drivers may be better suited for SiC MOSFETs as they can support lower short-circuit detection thresholds/detection times. Check out the UCC2173x-Q1 family or the UCC21710-Q1 to see this feature. 

Best,

Nancy

Hi Nancy

I understood that  desat function for sic-mosfet is possible even when using UCC21750.

Please explain why the overcurrent protection circuit of UCC21710-Q1 is more suitable when using SIC-MOSFET.

What are the main differences between SiC-MOSFET and IGBT during DESAT.

Best regards

f-kawashima

Hi,

IGBTs generally can withstand short-circuit conditions for longer than MOSFETs (up to 10 microseconds versus typically less than 5us). By using the overcurrent protection feature in the UCC21710, we can have shorter short-circuit detection times (hundreds of nanoseconds versus a few microseconds). Here is a link to download the calculator tool used to calculate the detection times for different UCC217xx detection schemes: https://www.ti.com/lit/zip/sluc695

Best,

Nancy 

Hellow Nancy

Thank you for your support.

I already checked calculator tool,as a result,tBLK is about 2us for the desat function of  the UCC21750

and about 200ns for the OC function of the UCC21710.

A difference of about 10 times can be confirmed.

So,how can I verify this time and whether the SiC-MOSFET is protected?

Best regards

f-kawashima

Hi,

The time the transistor can withstand should be a parameter given in the datasheet (usually denoted by SCWT, which stands for short-circuit withstand time). 

Best,

Nancy