IGBT and power transistors - Page 1
Forum section: electronics / beginners

author: IanBerry
author_rank: Contributor
timestamp: August 03, 2016, 06:54:29 pm
content: When searching for some high voltage/high current BJT's online (about 5 amps at 500 volts) I came across a transistor called an IGBT (Insulated Gate Bipolar Transistor) and they came in a casing that looked like a brick. These IGBTs were rating for 200 amps at 1000 volts. I couldn't find a BJT or a MOSFET for that matter that could handle that kind of power. What makes them capable of doing that? Also, am I just looking in the wrong places for high power BJT's? I have been doing google searches and checking Ebay.

author: tautech
author_rank: Super Contributor
timestamp: August 03, 2016, 07:26:34 pm
content: Welcome to the forum.A description of what you're trying to do will help with appropriate recommendations.

author: MosherIV
author_rank: Super Contributor
timestamp: August 03, 2016, 07:40:33 pm
content: QuoteProbably. Use the regular quality suppliers like Element14, RS, Digikey, Mouser etcI doubt you will find BJTs that can do both high current and high voltage, they can do one but not both.FETs will do the 5 amp and 100V that you mentioned.QuoteAs I said, try Element14, RS, Digikey, Mouser.The TI web site has parametric search.When looking for high stress components like this, I would NOT trust ANYTHING from ebay, not even resistors!

author: Kremmen
author_rank: Super Contributor
timestamp: August 03, 2016, 07:52:29 pm
content: The high power capacity and voltage are the result of details of the device construction. Along with thyristors, IGBTs have the highest current capacity but unlike thyristors, an IGBT is a true transistor. It is a hybrid however, combining a bipolar main conduction path with an insulated control gate such as a MOSFET would have. This hybrid construction is part of the reason for the high current and voltage capacity, but explaining just why this is, would take us rather deep in the physics of electron devices. Suffice it to say that compared to true MOSFETS, the IGBT is a bipolar device where the combined majority and minority charge carriers make possible higher current densities that the MOSFET majority carriers alone. Also the epitaxial construction results in a depletion region that prevents a phenomenon called punch-through up to higher voltages than is usual in your regular BJTs. It is all rather complicated making a truly simple answer infeasible.There are IGBTs that come in at least TO247 package if not smaller and still capable of 1200V Vce and lots of amps. Unless you also need high switching frequencies those could be something for you. But you should be aware that IGBTs suck at prioperly high frequencies due to the long tail in the switch off as there is no way to expedite discharging the gate charge from the insulated part inside the BT.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 03, 2016, 08:08:36 pm
content: It may help to realize, they don't do that simultaneously. 200A * 1000V is a lot of continuous power, but they are operated under those conditions for a fraction of a microsecond at a time. The rest of the time, they are dropping 200A * 2V or so (whatever Vce(sat) is at that current, and temperature), or 1000V and <1mA (whatever C-E leakage current is).Indeed, they are designed exclusively to do this! The amount of power an IGBT can dissipate, while at high voltage, is severely reduced compared to other types. IGBTs are not recommended for linear operation, such as in linear regulators, power amplifiers, etc. They are only good for switching, and they are damned good at it, too!Tim

author: madires
author_rank: Super Contributor
timestamp: August 03, 2016, 08:39:32 pm
content: BU508A

author: danadak
author_rank: Super Contributor
timestamp: August 04, 2016, 12:16:22 am
content: These might help -http://www.ixys.com/documents/appnotes/ixys_igbt_basic_i.pdfhttps://www.fairchildsemi.com/application-notes/AN/AN-9016.pdfhttp://www.infineon.com/dgdl/choosewisely.pdf?fileId=5546d462533600a40153574048b73edchttp://www.irf.com/technical-info/apphandbook.pdfhttps://openlibrary.org/publishers/International_RectifierRegards, Dana.

author: David Hess
author_rank: Super Contributor
timestamp: August 04, 2016, 01:42:22 am
content: Quote from: T3sl4co1l on August 03, 2016, 08:08:36 pmMost power MOSFETs now made are intended for switching applications and share the same problem with linear operation; their temperature coefficient reverses at appallingly low Vds so they suffer from something like secondary breakdown in a bipolar transistor operated at high voltage.Toshiba at one point made a complementary IGBT pair (GT20D101 andGT20D201?) intended for big linear audio amplifiers. You can also find power MOSFETs intended for linear operation as well.As far as really big devices, bipolars, MOSFETs, and IGBTs can be found in ginormous packages for power switching and conversion applications but I think IGBTs have almost completely taken over that market.