uSupply, Elektor Professional lab PS

[dougg]

In the September 2014 edition, Elektor have published a 'Professional Lab Power Supply' project. It takes a dirty 12 volt input, typically from a ATX desktop PS, inverts, transforms and rectifiers it to a voltage about 2 volts above what it wants, then sends it through a linear regulator. So it has electrical isolation between the input and output and claims up to 70% efficiency.

Is there anything uSupply could learn from this Elektor project? For example it gets around op amp voltage rail problems by using several DC/DC converters to obtain  +- 15 volts.

For those that can't see the schematic, it uses an Atmega32 for control, and opto-couplers for feedback. The output voltage is 0 to 30 volts, adjustable in 10 mV steps while the output current is 0 to 1 amp, adjustable in 10 mA steps. IMO more current (say up to 2 amps) at lower voltages would be useful.

[Marco]

It takes a dirty 12 volt input, typically from a ATX desktop PS, inverts, transforms

Really? I could see designing a bench supply by buck/boosting an ATX supply, but inverting to use standard transformer action seems a bit silly.

[mikerj]

Is there anything uSupply could learn from this Elektor project? For example it gets around op amp voltage rail problems by using several DC/DC converters to obtain  +- 15 volts.

The uSupply was supposed to be a reasonably simple design.  Adding in multiple switching regulators to move the supply rails outside an op-amps required output swing is fine, but it adds complexity and cost.