An Instantaneously Triggered Short-Circuit Protection Architecture for Boost Switching DC/DC Converters

This paper presents a protection circuit architecture that helps us to reduce the chances of damages in a boost switching converter due to fault conditions of output short-to-ground or power-switch short-circuits. Those two short-circuit faults can cause the inductor current to run away and result in damages. The proposed protection circuit can detect those two fault conditions within a few microseconds and then isolate the converter from its power supply. The fault detection is implemented by sensing the voltage drop across the primary inductor in a 1:1 coupled transformer which replaces the single-winding inductor in a boost converter. If a short-circuit fault happens at either the output load or at the power switch, the secondary inductor will shoot current to turn off a pass PMOSFET, which disconnects the primary inductor from the input supply. The protection circuit was built on the top of a commercial boost converter and was verified under short-circuit faults over a wide load current range. The proposed protection structure effectively reduced the inductor current overshoot during short-circuit event at the expenses of 1.2% drop of the peak efficiency during normal operation.