[Thatvalveguy]

Pass transistors shorting out shouldn't happen in a well designed supply, this supply uses the LT1084 5A regulator, the LT1076 internally limits the switch current which gives the ramp voltage on the output.

A diode anti parallel over both devices mean that if the HT would be inadvertently connected to the positive terminal of the regulator the current would be eaten up by the relatively low impedance of the supply.

The Sussex limits the output current, and if some load is connected to the supply, nothing should break.

The switcher keeps the voltage over the 1084 at about 1.2V, by taking a zener diode as opposed to the 1n4148 one can choose higher differential voltage over the regulator chip.

dissipation in the 1084 device is about 1.2 watts per amp of output current, overall efficiency depends mostly on the switcher used, if a newer device is used that uses Fets instead of bipolars an overal efficiency in excess of 85% should be possible.

I etched the prototype PCB, the circuit works much better without the long leads present, the main switching frequency is propagating into the output somewhat, however the optional output filter of 10uH 220uF seems to reject all the choppy harmonics.

All in all, it works relatively well, the LT1076 sometimes runs into switch current limiting starting into a cold heater, which is to be expected because the inductance 47uH instead of 100uH.