UCC5350: VEE2 limts for Split Outputs version

Hi MB,

Voltage is just a measure of potential between two points. The output die is isolated, so usually voltage ratings for the output are referred to VEE itself. 

For the -E version, there is a VEE rating is referenced to GND2.  The GND2 pin is designed to connect to either a FET source or the IGBT emitter, mostly so that the UVLO can trigger if VCC2 enters a brown-out condition. VEE and GND2 can be shorted, since 0V is within the -17.5V to 0.3V rating. 

Most important is the VCC2-VEE2 recommended max rating of 33V.

For the split output, you can reference the VCC and VEE to the FET source=0V. In that case, you can have

VEE=0V, and VCC=33V, 

VEE= -3V, and VCC=30V, 

VEE=-17.5 and VCC=15.5

VEE= -33 and VCC=0V.

All of these will stay within the rated VCC-VEE power supply voltage range of the split output device.

For the E version, you would have to limit VEE-GND2 to 17.5, but that limit does not apply to devices without a GND2 pin/

Best regards,

Sean

Hi MB,

That is a lot of input decoupling! One capacitor should be enough for VCCI. Have you had issues in the past?

Also, there are many parallel Rg. Is this to reduce inductance or for to improve thermal sinking? I don't think that these will need to dissipate that much power, so you can probably get away with only one resistor.

Usually you need a 100nF capacitor across VDD and VSS to protect the gate driver from transient overvoltage. Also, usually you need a Zener circuit to reference the floating isolated power supply to the Vsource of the driven FET:

Best regards,

Sean