ISOLATION-TYPE FLYBACK CONVERTER FOR LIGHT EMITTING DIODE DRIVER

摘要

PURPOSE: An insulation type flyback conversion circuit is provided to improve a power factor and to change brightness according to control of a conduction angle of a power supply. CONSTITUTION: A snubber circuit unit(300) is connected with the primary side of a transformer(20). The snubber circuit unit prevents overvoltage and overcurrent. A snubber power detection unit(400) detects snubber voltage of the snubber circuit unit. The snubber power detection unit generates reference voltage being proportional to snubber voltage. A source end of a switching unit is connected with a current sensing resistor. A drain end of the switching unit is connected with the snubber circuit unit. A control unit(100) controls the switching unit(200) and constantly maintains current of a secondary side. [Reference numerals] (102) Boundary mode timing generator