Part Number: UCC5390-Q1
Other Parts Discussed in Thread: UCC5390, UCC23525, UCC23711, UCC21750, UCC5350
Tool/software:
Hi TI
I am currently working on a SST project in this we using the SiC MOSFET from microchip( MSC025SMA330B4N) having the rating of 3300V and gate current of above 16A and we require the DESAT functionality also can you suggest the gate driver match above specification.
Hi Kayala,
Do you mean 16A of MSC025SMA330B4N drain current? There is a graph in that SiC FET's datasheet for expected switching loss vs. gate drive resistance for a 50A drain current. The 16A switching losses will be a fraction close to 16/50 of these 50A values:
The UCC5390 has an internal Roh of 12 ohms. It will make higher switching losses than the UCC23535, which has an output resistance of about 5 ohms. For lower resistance, you can add an external BJT totem pole buffer, which can provide resistances less than 1 ohm. However, this will slam the current on and off, resulting in high overshoot at the FETs. Your FET is extremely high voltage, so this might not be a problem.
If you need DESAT protection, we have a device with the same output resistance as UCC23525 with a DESAT feature, called UCC23711. Accelerated product launch samples will be available in September if you are interested. UCC21750 is a device with the same drive strength as UCC5390 with a DESAT pin.
Best regards,
Sean
No 16A is not drain current actually when you see the datasheet MSC025SMA330B4N
Total gate charge is 410 nano Columbs
Fall time (or) Rise time whichever is greater = 26 nano seconds
Gate current required is 410/26=15.77A
We require the gate drive circuit which able support peak output current is more than 16A and It able to work 2800V working voltage and more than 5000V
Withstand isolation voltage up to 1min in UL certified. And also, it should have DESAT feature, and above conditions work with Silicon carbide MOSFET mentioned. So please suggest the gate driver support and all this requirement so mention those drivers. Thank and waiting for your reply
Actually I am attaching some sample specification how it should look like please go through is make better idea
Hi Kayala,
Gate driver output current does not quite work that way. Below are the Id= 75A, 600V switching waveforms I measured for C3M0015065D, a similar SiC FET.
The 26ns voltage fall time is only the third of four periods in the full 410nC FET turn-on cycle. The first is the cutoff region, where Vgs is charged to Vth, second is the active/saturation region where Id ramps from 0A to the full Id, next is the saturation region (fall time), and then finally the Rdson region, where Vgs rises fully to 15V.
The gate driver output current is shown below in red. As you can see, it does not rise instantaneously from 0A to its peak value. It is limited in the cutoff region by its transconductance. An external BJT totem pole can have a faster rise time, but most gate drivers are made of lower cost CMOS devices. Increasing the supply voltage helps extract more Iout also.
More importantly, during the Id rise time an Vds fall time, which determine Eon, the gate driver's output voltage is already close to the positive rail, and Iout is limited by Roh, not the saturation current. You can derive Roh and Rol (for Eoff) from datasheet output low and output high levels. In this test, a small current like 20mA is injected into the output and the voltage change is measured.
UCC5350 (10A peak Iout): Measured max current is 2.2A, switching loss is 3mJ. The Roh is about 12 ohms.
UCC23525 (5A peak Iout): Measured max current is 2.3A, switching loss is 2.6mJ. The Roh is about 5 ohms when only 1 ohm is added externally.
The working isolation voltage is given in Vrms, but if you are using a DC rail, you should multiply this value by sqrt(2), or use the Vdc rating in the datasheet.
If you require a DESAT feature, the UCC23711 or UCC21750 will have this additional feature.
Best regards,
Sean
