SWITCHING MODE POWER SUPPLY USING FREQUENCY MODULATION TYPE AND PULSE WIDTH MODULATION TYPE

摘要

PURPOSE: A switching mode power supply using the frequency modulation method and the pulse width modulation method are provided to reduce the standby power in the low load by modifying the switching frequency of the main switch to the cascade type according to the feedback voltage using a frequency variation circuit. CONSTITUTION: A power supplying unit(100) supplies the DC voltage to a primary coil of a transformer. An output unit(200) outputs the output voltage through a secondary coil of the transformer. A feedback circuit unit(300) generates the feedback voltage from the output voltage. A switching controller(400) controls the switching of the main switch to the switching frequency provided from the pulse width modulator.