Technique for combining in-rush current limiting and short circuit current limiting

Abstract

A circuit that protects from high power-on in-rush currents and short circuits. The circuit has a pass transistor and a parallel smaller transistor. A comparator senses when an output voltage crosses a reference and turns off the pass transistor and turns on the parallel smaller transistor. The parallel smaller transistor has a higher 'on' resistance so that the short circuit or the in-rush current does not harm the electronics. When the short circuit or in-rush current condition is removed, the comparator senses this condition and returns to the normal operation where the pass transistor is on and the parallel small transistor is off.