Buck type DC/DC convertor circuit with anti-ringing modular circuit

The present invention discloses a buck type DC/DC convertor circuit with an anti-ringing modular circuit. The anti-ringing modular circuit is integrated into a chip, and comprises an oscillator clockmodule, a charge pump module, a high-voltage level shift module and a high-voltage NMOS tube MSW. The operating principle of the system comprises that: under a light-load application, when an induction current when a DC/DC convertor works is smaller than 0, the system enters a DCM working mode, at the moment, upper and lower power tubes MTOP and MBOT are disconnected, internal logic signals ZCD and Mode enables the anti-ringing modular circuit, the high-voltage NMOS tube MSW is controlled to perform short circuit of an inductor so as to switch off an LC oscillation circuit so as to avoid generation of a ringing phenomenon when the DCM works in light-load and allow the system to be stable in a full load application. The NMOS tube is commonly used as a switching device and has advantages atthe aspects of the on resi