Split Rail Linear Power Supply

For step by step details see the application report creating a split rail power supply with a wide input voltage buck regulator charge pumps are a popular and easy way of inverting positive rails.

Split rail linear power supply.

I build up a simple low voltage supply to setup the framework for the l. This document outlines a step by stepmethod for designing the split rail power supply. The input supply voltage range is suitable for use with lithium ion batteries or from a fixed 3 3 v supply. I thought it would be interesting to do a theory video on linear power supply design.

Splitting a rail using the voltage reference will often mean compromising a bit on the symmetry of the split for example if a 3v3 rail is to be split then the closest would be to use the 1 8v output reference which gives a 1 8 1 5v asymmetrical supply. Only the ref3318 is available with a 1 8v output so it could be used. The split rail power supply uses a wide input voltage step downregulator as an inverting power supply to create the negative supply rail. This results in the load current of both regulators to be equal in magnitude.

The fly buck method is a more complex technique. The positive supply rail is created from a standard off the shelfcoupled inductor from coilcraft. The tps65133 is designed to supply any system requiring 5 0 v supply rails. Each output can supply up to 250 ma of output current.

Power supplies are available at mouser electronics from industry leading manufacturers mouser is an authorized distributor for many power supply manufacturers including artesyn bel power cosel cui inc delta mean well phoenix contact recom tdk lambda traco power vicor xp power more. In a split voltage power supply application the analog circuit is connected between the positive voltage rail and the negative voltage rail.