COTS solutions for ±18V DC (or even ±20V) and ±30V PCB-mounted power supplies in the 3-5 Watt range

power supply

Most manufacturers make DC-DC converters with only ±15V or ±24V outputs for driving opamps. Opamps generally fall in several max-DC-supply classes. Typical are the ±22V ones (e.g. LM741 and a ton more), some of which do have reliable operation up to ±20V (e.g. the LM741A). Alas DC-DC converters in between ±15V and ±24V (e.g. ±18V) are extremely boutique items than can be very hard to source. So, what are practical solutions for building your own (on par with COTS devices in terms of characteristics) wile using as few components as possible? A ±9V with voltage doublers for example is a practical solution?

The same question applies to ±30V sources that would be useful for getting most output swing out of an OPA551 for example (which has its characteristics given at this supply voltage, by the way.)

Best Answer

Assuming you're doing the sort of thing that can live without galvanic isolation, there are plenty of easy solutions. If you don't mind a transformer, here is one of the lowest parts-count (and probably lowest cost) solutions, using the ubiquitous LM2577:

enter image description here

The simpler solutions (as with the cheaper DC-DC converters) tend to have so-so regulation, require a minimum load etc. Be mindful of this if you're up near the absolute maximum voltage input of the load semiconductors- the output voltage could be volts above nominal with a very light load.

Related Topic