Power Transistor Question

[Verboten]

I have what I believe to be a couple of large power transistors (Toshiba MG200M1FK1). The packaging is similar tothis ebay auction but the 4 terminals are layed out and labeled like this : C | B1 | BX | E with C & E being very large terminals and B1 & BX being smaller.

I did a bit of searching and found this info:
Part Number = MG200M1FK1
Description = Darlington Independent Power Module - 3-Stage Darlington
Manufacturer = Toshiba
Isolated Case (Y/N) = Yes
Circuits Per Package = 1
V(BR)CEO (V) = 880
V(BR)CBO (V) = 1.0k
I(C) Abs.(A) Collector Current = 200
Absolute Max. Power Diss. (W) = 1.4k
R(thJC) (°C/W) = 89m
h(FE) Min. Static Current Gain = 100
@I(C) (A) (Test Condition) = 200
@VCE (test) = 5.0
V(CE)sat Max.(V) = 2.5
@I(C) (A) (Test Condition) = 200
@I(B) (A) (Test Condition) = 4.0
t(f) Max. (s) Fall time. = 5.0u
Package = MODULE-var

I would like to use a MOSFET or smaller transistor to trigger this one from my parallel port - I already know how to trigger a small mosfet. The goal would be to get a DC motor to be switched on by computer timer or outside switches that are fed into it - one direction would be just fine at first.

I think that this transistor came out of a large motor controller and I gather that its max is 880V 200A to a combination of 1.4kW - would there be a problem with running something as small as 90V 10A (1HP).

Why does this transistor have 4 terminals. I imagine that one of B1 or Bx is the B leg of the transistor - but which one and what does the other do?

I have had very little electronics education and almost all of those specs go way over my head. What voltage or current do I need to apply to trigger the larger transistor (is the information there to determine this)? Would this be considered a proper application for this type of part?

Any help or advice will be appreciated.
Thanks,
Jason

[Al_The_Man]

On large power transistors the common for the gate or base is also pinned out
For example on the ebay pic it shows the common as E & e. this is to prevent false triggering due to emitter currents in the trigger or signal input common lead.
You should find that b1 or bx is common to E.
Al.

[Verboten]

Al - thanks for the reply, it has helped but I am still quite a bit confused.

I have done more research and reckless fiddling but there is more that I want to understand. Here goes:

In the ebay picture e and E are connected without anything inbetween them? Why are there two terminals - convenience?

The diode over the transistor provides a pathway for current to flow from the emitter to the collector to correct a momentary situation where E might Become more positive than C- right?

I'm fairly sure that B1 on mine is the Base of the transistor. I triggered a load of a small 24 vdc motor by applying +5V to this terminal. Do I need to worry about connecting anything to BX?
There was a drop of about 1.5 V beween C and E would that be considered normal or was the 5 V that I applied to the base not enough to fully open the gate? I know that it is current that operates the gate but I measure 200 ohms resistance between B1 and E (without any power applied)- that makes for .025 A at 5 V right? Is that enough? too much? way too much?

[Al_The_Man]

If you have found that B1 is the base input then the drive signal common should be connected to BX and the power ground connected to E, although in theory they are the same potential, this avoids emitter currents affecting the base signal, this is due the very high current this transistor is capable of and there is the possibility of some volt drop in the emitter lead due to foil/wire resistance and this would effectively be in series with the base feed if it were not fed separately.
This is a high gain 100hfe (darlington) transistor, the specs. show a base current in test of 4amps. to determine the minimum current for saturation, place a load in the collector and feed the base BX & B1 with an increasing current until the volt drop from E to C drops to a minimum voltage until increasing the base current no longer causes further drop, this is a crude way of establishing the base current you will need for max. turn on.
The reverse diode prevents the collector moving more negative than the emitter.
Also an ordinary digital VOM on the resistance range will give you misleading readings on solid state device due to its own high internal resistance.
Al.

[Verboten]

Al, Thanks again for the help.

It makes a lot more sense to me now. I have it wired up correctly now.

Another question though: How quickly can this thing cycle from on to off? Could it be used for PWM?

Thanks,
Jason

[Al_The_Man]

Typically they are used in PWM switching servo amplifiers etc. The spec shows fast switching.
Al.

[mauriceduteau]

I learned a lot about motor control from the 'open source motor control' project.
http://groups.yahoo.com/group/osmc/
It was a while ago that we developed this controller for a DC powered floor cleaning machine, but I remember one important lesson was that a normal output like a parallel port or TTL pin doesnt have enough punch to turn a mosfet on quickly resulting in a lot of heat buildup. Use a mosfet driver chip in between your controller and the mosfet.