Rise/Fall Time Issue with STW3N170 in H-Bridge to test High dv/dt test setup for our sensor using driver used UCC21330

[Narana162]

I'm using MOSFET STW3N170 in an H-Bridge configuration along with TI’s gate driver UCC21330. During testing, observed an issue with the switching speed as the test is for high dv/dt

Observed Behavior:

• • Rise time ≈ 5 µs
  • Fall time ≈ 5 µs
• Test Conditions:
  • Gate resistance: 2.2 Ω
  • Gate driver isolated pulse rise time: ~30 ns
• Expectation:
  • As per the STW3N170 datasheet, the rise and fall times are specified in the nanosecond range, but the MOSFET switching is significantly slower.

This slower rise/fall is limiting dv/dt performance, which is critical for our H-Bridge application. Could you please advise:

1. If there are any specific considerations when using MOSFET STW3N170 with high-speed drivers like UCC21330.
2. Whether additional circuit or layout recommendations are required to achieve faster switching.

 

[Peter BENSCH]

Welcome @Narana162, to the community!

Well, the STW3N170 can certainly meet the specifications if the environmental conditions allow it, which includes not only the layout and the gate driver, but also the devices located between that driver and the gate. Perhaps someone can take a look if you insert the schematics and the layout excerpt here as an image. However, only the manufacturer or their support forum will be able to help you with the gate driver.

Regards
/Peter

[AScha.3]

30ns -> 5us .... Whats the test condition for the mosfet ? load ? circuit ?

Seems you look at a not loaded output, so you see the slow rise/fall, just charging the capacities.

You have to test it with some load !