I have just finished the power supply project.
Circuit supply can be done with 48 volt dc 150 watts smps or transformer. The circuit requires a 5 volt additional supply with 48 volts.
Mje3055 can be used instead of 2n3055. This transistor should be cooled with a 5 watt cooler. The 3055 transistor heats up to 5 watts maximum at each voltage in a 4 amp load current.
Voltage setting is done with 50k potentiometer and current setting is done with 1k potentiometer.
I have not yet implemented the circuit practically. I will do it. There may be a problem. Those who want to do can make the circuit. The circuit is working in a simulated environment.
The characteristic of the circuit is that it does not need a very large cooler and different supply voltages.
C3, C6 and C10 must be low esr (low impedance) type.
Extract the rar file to a folder.
You can run the ASC file with the free ltspice simulator.
The circuit is working in the high side step down topology. Pre-regulation. The goal is to produce 1.2 volts of the required 3055 emitter voltage. The 48 volt input voltage can be reduced to 40 - 45 volts. I chose it because it has a 48 volt standard smps output.
For minimum heating of the 3055, the Vce voltage had to be at a minimum. I think the best voltage is 1.2 volts. The collector power consumption of this transistor is 1.28 = 4.8 watts at 4 amps.
To make the output ampere 8 amps, we need to parallel the pair of bc 327 mje3055. I need to use 3 pairs for 12 amps. But in this case you need to increase your power in the step down section.