For most non-synchronous rectification boost switching converters that use inductors, there is a DC path between its input and output, as shown in Figure 1. The existence of this pathway will cause two undesirable consequences:

First, once the output is short-circuited or the serious overload time exceeds several hundred milliseconds, the diode (usually a Schottky diode) will be overheated and damaged;

Second, when due to some reason, such as artificial shutdown, the switching oscillator circuit stops working, there is still voltage at the load end, but only one diode drop lower than the input end. At this time, the output will still consume energy. In addition, if the residual voltage is lower than the steady-state operating voltage range of the load, the circuit will be in an uncertain state.