SWITCHED MODE POWER SUPPLY WITH IMPROVED LIGHT LOAD EFFICIENCY

摘要

A control circuit operable to control the switching of switching elements in a switched mode power supply. The control circuit comprises a switching control signal generator operable to generate control signals for switching the switching elements such that the switched mode power supply converts an input voltage (Vin) to an output voltage Vout). The control circuit further comprises an operation mode setting module which is operable to receive a signal (I) indicative of a current flowing to a load that is connected to an output of the switched mode power supply, and operable to cause the switching control signal generator to generate the control signals so as to operate the switched mode power supply in a continuous conduction mode or a pulse skipping mode in dependence upon the current.

主权项

1. A control circuit operable to control the switching of switching elements in a switched mode power supply, comprising:
a switching control signal generator operable to generate control signals for switching the switching elements such that the switched mode power supply converts an input voltage (Vin) to an output voltage (Vout); and an operation mode setting module operable to receive a signal (I) indicative of a current flowing to a load that is connected to an output of the switched mode power supply, and operable to cause the switching control signal generator to generate the control signals so as to operate the switched mode power supply in a continuous conduction mode or a pulse skipping mode in dependence upon the current, wherein in the pulse skipping mode the switching elements are turned OFF for at least one switching period of the switched mode power supply but the switched mode power supply continues to supply power to the load; wherein the operation mode setting module is operable to monitor the signal (I) indicative of the current to determine whether the current exceeds a threshold, and is operable to control the switching control signal generator to generate the control signals such that, when the current exceeds the threshold, the switched mode power supply operates in the continuous conduction mode and, upon determining that the current has fallen to or below the threshold, operation of the switched mode power supply is changed from the continuous conduction mode to the pulse skipping mode so that the pulse skipping mode is entered from the continuous conduction mode.