Switching mode power supply and its control method

The switched mode power supply and its control method are disclosed. Each channel in the switching mode power supplies to support the multi-channel outputs to produce a pulse signal for each switching operation. Control is fed back to the in sync with the pulse signal to generate a blanking time, the pulse other channel blanking signal for filtering the signal for a reference channel, if the transition between the high level and the low level occurs in the pulse signal of the other channel around the reference channel by prevents the noise caused by the switching at the time of non-reference channels generated pulse signal of the reference channel. The controller is the noise generated by its own internal signal by feedback to create further input filter itself blanking signal of the pulse signal during the blanking time when a transition between a high level and a low level in the pulse signal of the reference channel generation It prevents. According to this structure, a desired output voltage to effectively remove the switching noise between channels, and can operate the system stably.