I picked up half a dozen devices at a garage sale, with the thought of a good opportunity to make a battery spot welder - data sheet attached. So I have an Arduino circuit that has programmable pulses (5v, 100ms duration, 50ms pause in between), a bridge rectifier rated at 300A, and a big power transformer that puts out 3.8v at 400amps. I'm not really versed in IGBT/Power transistor circuit design, but I do know that IGBT are voltage driven, vs a transistor's current. So I thought I'd do a bench test on one of the bricks before putting it all together. The data sheet shows the nominal Vbe as 3.5v, max 7v - so 5v should be perfect. So I put a test load on the device and powered the base via a 5v, current limited power supply. Ibe current was a surprising 3.5 amps. The datasheet shows the gain (hFE) as 100.
Am I to understand that expecting to switch a 300A current load, I have to supply 3 amps thru the base - or am I missing something here?
If so, why the low gain on a Darlington design?
Finally, would an IGBT work better here, with direct drive off the Arduino, or will it need a driver nonetheless?
Am I to understand that expecting to switch a 300A current load, I have to supply 3 amps thru the base - or am I missing something here?
If so, why the low gain on a Darlington design?
Finally, would an IGBT work better here, with direct drive off the Arduino, or will it need a driver nonetheless?
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