SWITCH MODE POWER SUPPLY APPARATUS

摘要

PURPOSE: A switch mode power supply apparatus is provided to reduce power consumption in standby mode and to switch the standby mode to the normal mode rapidly. CONSTITUTION: The first and second transformers(TRANS1,TRANS2) generate the first and second voltages upon application of power. The control device compares the sense voltage level with the feedback voltage level to modulate pulse width of the switching control signal and controls current flowing the primary winding of the first transformer. The standby mode sensing device allows the control device to generate the control signal during predetermined period repeatedly. The mode power sensing device allows the control device to control the pulse width of the switching control signal maximally when sensing that the second voltage is lower than the predetermined level.