My picaxes love IGBT's!

[andrewpro]

I always see alot of talk of MOSFETS and drivers and all kindsa things on the boards here, and wanted to share an experience I had/am having.

I was never one ot really buy into Insulated Gate Bipolar Transistors because Iw as content with power mosfets and drivers, etc. I recently came into posetion of a number of IGBT's and I gotta tell ya...I'm half tempted to jsut give away my power mosfets!

The specific device I'm talking about here is from Fairchild Semiconductor, part number ISL9V3040P3 (whew, that's a mouthfull!!). It's designed for automotive ignition circuits technically, but the more I paly with them, the more I love them. They've got logic level switching of up to 25 amps, and I've PWM'ed 10 amps continuously straight off of a picaxe pin and had no problems what so ever. I dont have a 25 amp ps, otherwise I'd give it a shot. A resistor between the picaxe pin and the gate isn't a bad idea either.

Just thought I'd share this, as it takes the best of both worlds with BJT's and power MOSFETS, and rolls them up into one hell of a device!

--Andy P

 

[evanh]

Yep, their gate capacitance will be lower compared to the equivalent powerMOS. IGBT losses are better at high(mains) voltages but notably worse at low(vehicle) voltages. There is the clean resistive like action of the MOS where as an IGBT is diodic and dalington-like to boot. I doubt IGBTs ever get used for their linear mode.

The gate resistor is vital driver protection for both transistor types in a switching circuit and so is a snubber, placed across the gate-source pins, transorbs are weapon of choice here.


Evan

 

[andrewpro]

Yeah...The more I play with them, the more I find their lmitations and strengths. I dont want to leave the impression to anyone that they're a drop in replacement for setups youve already got going. There is alot of caveats, etc, but I'm finding that for alot of big power applications, these little guys (sorta little...I've got TO-220's) are very nice. Right now I'm working on the drive system for my radio telescope dishes which use 90 volt 200 watt motors, and they're seeming ot be the cats meow. Still taking some getting used to, experimentation, and playing though.

--Andy P