Current Limiting for the MAX1864 Auxiliary Regulator

Abstract: The MAX1864 is a low-cost, multiple-output converter consisting of a switching buck circuit and two positive linear regulators. Although this integrated circuit's basic application circuit offers a low cost multiple output supply, designs that require current limited linear regulator outputs (the switching buck is already current limited) need to consult this application note. If shorts are expected at the linear regulator outputs, or where mishaps can cause the power dissipation of the external pass element to be exceeded, current limiting should be employed. Further protection can be had with a foldback current-limiting circuit. This application note details the design and implementation of current limiting for the MAX1864 positive linear regulators.