I need a constant current source able to deliver 15A. I know how to configure an LM317T as a CC source with the programming resistor between the output and adjust pins (and the power required, which in this case is 1.25v * 15A), and use a pass transistor to handle the extra current.
However, I'd like to use multiple PNP pass transistors to help spread the current (and thermal) load. I know that paralleling transistors directly is not advised without compensating for transistor variances by using a small value resistor. Most paralleled transistor circuits I've seen use this resistor in the emitter, but not sure exactly how it would work in this application.
BTW: I seem to have a ton of TIP127 PNP Darlington transistors for some reason, so I'd like to use those if I can.
Edit: Oh yeah, I did try the search, but the only results I seem to get are circuits for LED drivers - I know how to regulate lower currents...
However, I'd like to use multiple PNP pass transistors to help spread the current (and thermal) load. I know that paralleling transistors directly is not advised without compensating for transistor variances by using a small value resistor. Most paralleled transistor circuits I've seen use this resistor in the emitter, but not sure exactly how it would work in this application.
BTW: I seem to have a ton of TIP127 PNP Darlington transistors for some reason, so I'd like to use those if I can.
Edit: Oh yeah, I did try the search, but the only results I seem to get are circuits for LED drivers - I know how to regulate lower currents...
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