Dual-mode synchronous rectification control circuit for DCM and CCM

The invention provides a dual-mode synchronous rectification control circuit for a DCM and a CCM, belonging to the technical field of power management. The structure of the circuit is simple, the rectification conduction loss can be effectively reduced, and high efficiency of synchronous rectification is realized. Minimum dead time control is realized by a second negative level detector. A turn-off time shielding module prevents the wrong turn-on of a synchronous rectifier tube M2, and a turn-on time shielding module prevents the wrong turn-off of the synchronous rectifier tube M2. Drain electrodes of LDMOS and DEMOS high voltage devices are used by a first sampling end to bear high voltage, the clamping of a drain end VD of the synchronous rectifier tube M2 by a Zener is avoided, and the current leakage to the ground by the drain end VD of the synchronous rectifier tube M2 is prevented. The high efficiency of synchronous rectification is realized by the above measures together. In addition, a synchronous con