A SWITCH MODE POWER SUPPLY HAVING A STANDBY MODE

摘要

PURPOSE: A switching mode power supply(SMPS) is provided to be capable of reducing an input power by performing a switch operation of the SMPS during a predetermined interval of time and stopping the switching operation during a predetermined interval of time, at a standby mode. CONSTITUTION: A power supplying part(100) receives an input power(Vin) to supply a desired output voltage(Vout) to a load(500) according to a duty of a main switch(SW1). A feedback circuit part(200) senses an output voltage of the load(500) to output a feedback voltage(Vfb) corresponding to the sensed output voltage. A current supplying part(300) supplies a current to a capacitor(Cfb) of the feedback circuit(200) and consists of two current sources(I1,I2) and a switch(SW2). In the case where a system is at a normal operating mode, the switch(SW2) is switched on/off. A switch driving part(400) is supplied with the feedback voltage(Vfb) from the feedback circuit(200) to control the main switch(SW1) according to the feedback voltage.