| BrianG |
04.04.2011 04:55 PM |
Quote:
Originally Posted by Pdelcast
(Post 403452)
Well, that's not really a good idea... Modern NPN power transistors won't take too much base current. Better to use two power schottky diodes.
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Lol, I guess my transistor bin needs updating! I mentioned it because a while back I wanted diodes that had the same thermal characteristics as a set of transistors I was using for a class AB amp and using the same transistors connected as a diode worked great. But, for higher currents, I suppose this wouldn't be advised. My bad.
Quote:
Originally Posted by Pdelcast
(Post 403453)
Also,
Brian, I disagree with your 2V dropout -- if you look at your chart there is practically no dropout. If there was 2V of dropout, a 7V input would yield a 5V output, and a 5V input would yield a 3V output. That's not the case.
The CC BEC uses a P-channel MOSFET for the power switch. The only dropout should be from the resistance of the MOSFET itself... So around 30 millivolts or so.
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I only said 2v because, if you look at the chart, that's the dropout value where the output voltage is most constant for the various loads. Also, not shown on the drop-out test, but I seem to remember there being more HF noise at the lower differential voltages. So, since this is going in a sensitive device, I erred on the side of caution just in case. |
