Switching power supply and intermittent power saving mode control circuit and method thereof

An intermittent power saving mode control method, comprising:

• controlling a switching power supply to operate alternately between a work mode and a sleep mode under a burst mode;
• controlling the switching power supply to operate in the sleep mode according a first reference voltage, the first reference voltage is constant;
• controlling the switching power supply to operate in the work mode according to a second reference voltage;
• monitoring an alternating frequency of the switching power supply in the burst mode, wherein the alternating frequency is a frequency value that the switching power supply changes from a current work mode to a next work mode or from a current sleep mode to a next sleep mode, wherein in the work mode, a power switch of the switching power supply is periodically turned on and turned off and in sleep mode, the switching power supply remains off;
• and
• adjusting the second reference voltage according to the alternating frequency, so that the alternating frequency is within a range of a first frequency to a second frequency.