keegi miki süvenes asjasse ja tegi kättesaadavatest juppidest uue ploki (jutt siis DELCO 16061602):
jutt ka juurde - ei viitsi ise sellisesse elektroonikasse eriti süveneda
Can't make it any simpler than this, just a NPN input driving three power MOSFET transistors with the input characteristics identical to the prototype. Seven resistors and four transistors. Why the TIP3055 for the input transistor instead of a cheap 2N3904? It's heat sink mounted like the other three and gives me three stiff terminals for mounted the loose components, the input circuit matches the OE and the circuit has a gain of less than unity. There is an advantage in this in that that low impedance input resistive circuit gives a much narrower trip point at the 2.8 V level like the OE. The 2700 ohm gate resistors give a gentle ramp in the turn on and off switching of the MOSFETS of about 20 microseconds. The resistive divider in the TIP 3055 cuts down the drain voltage for protection using the worse case value of 22 Volts with the Delco CS-144 alternator that is clamped at that voltage.
Was concerned about the MOSFETS operating in the linear mode, but forgot I was designing this thing for myself and not for production, the linear mode is where these transistors can be half on or half off causing excessive power dissipation and would have to do that if price were the object, only use one power MOSFET instead of three, so it cost me a couple of bucks, still much cheaper than anything on the market. And since the worse case power dissipation these three will see is only 70 watts, these three can handle 450 watts at 25*C, so who even cares if they go in the linear mode.
Valmis asi näeb tal välja selline - ja täitsa töötab:
kogu jutt siin - tegijaks NickD
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