Method for realizing pulse check through digital circuit

The invention relates to a method for realizing pulse check through a digital circuit, which belongs to the technical field of IGBT (insulated gate bipolar transistor) applications of power electronics. The technical scheme comprises the following steps of: (1) performing frequency division on a pulse signal returned by an IGBT via a D trigger, then comparing the pulse signal with an original pulse, enabling the signal after comparison and a power supply fault signal SO emitted by the IGBT to pass through an or gate and then outputting a series of 220ns short pulses; (2) removing the part from a rising edge to about 220-250nm from the series of the pulses to remove a time delay signal generated by pulse comparison, and performing broadening treatment on the remaining signal, wherein the broadening width is decided by the number of external CLK (clocks) and triggers; and (3) finally outputting a low-level zero signal if an FO (fiber optic) alarm or an SO alarm does not exist; and outputting the pulse signal de