20 w triac dimmable led driver using LT3799 driver
A very simple triac dimmable led driver electronic circuit can be designed using the LT3799 isolated flyback controller with power factor correction specifically designed for driving LEDs.
This triac dimmable led driver electronic circuit design project is capable to provide a 20 watts power to LEDs .The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler.
Utilizing an onboard multiplier, the LT3799 typically achieves power factors of 0.97.
The circuit design is very simple requiring few external electronic parts .
The LT3799 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part.
This circuit operates over a wide range input voltage from 90 to 265 volts AC.
You can use this circuit for a standard input voltage ( 110 volts or 220 volts ) or you can use a an optimized configuration circuit that will work for a wide range input voltage .
To modify the circuit to a standard input voltage or for a universal configuration type you can select values for components that needs to be changed from the table bellow .
BR1 bridge diode can be HD06 type from DIODES, INC., D1 is CMR1U-06M from CENTRAL SEMICONDUCTOR ; D2, D3: BAV20W from DIODES INC. , DR: CMR1U-02M from CENTRAL SEMICONDUCTOR, Z1: SMBJ170A from FAIRCHILD Z2: CMZ5938B from CENTRAL SEMICONDUCTOR ,T1 transformer : JA4429-AL from COILCRAFT and M1 MOSFET: FDPF15N65 from FAIRCHILD .