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Re: Driver for IGBT? (-ve off and +ve on from CMOS)

Subject: Re: Driver for IGBT? -ve off and +ve on from CMOS
From: Fred Bloggs
Date: Mon, 10 Oct 2005 11:01:21 GMT
Newsgroups: sci.electronics.basics, sci.electronics.design
I would like to drive an IGBT from a microcontroller (CMOS).
Is there a driver circuit that can outputs around  +15v (on) and a -5v (off)
for  switching frequencies around 40Khz.
I think -ve voltage supply is avaliable
What is this type of circuit called?

Surprisingly it is called a gate driver circuit. IGBTs imply large power switching so that even though the switching frequency is a modest 40KHz, the driver is still required to switch the device through ON/OFF transitions quickly to reduce losses and component heating. Micrel at http://www.micrel.com manufactures a line of powerful gate driver products capable of handling nearly any situation. The most basic part in their line-up is the MIC4120, a non-inverting driver capable of supporting 6A peak gate drive currents. A high speed interface to a microcontroller might look like this:
             View in a fixed-width font such as Courier.
 .
 .
 .   CMOS>-[1.5K]-+-[10K]-+                 +15V
 .                |       |                  |
 .                 >|     |                  |
 .           BC557  |-----+    +-----+-------+---------+
 .                 /|     |    |     |       | MIC4120 |
 .                |      ---   |     |   -----------   |
 .                |      ///   | 0.1u|  |   1,8     |  |0.1u
 .                |            |    === |   |\      | ===
 .                |            |     |  |2  | \  6,7|  |
 .                +---------------------|---|  >----|----[10]-> To
 .                |            |     |  |   | /     |  |
 .                |            |1u   |  |   |/      |  |    IGBT GATE
 .              [1.2K]        ===    |  |   4,5     |  |
 .                |            |     |   -----------   |
 .                |            |     |       |         |
 .                +------------+-----+-------+---------+
 .                                           |
 .                                           |
 .                                         -5V
 .
 .


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