Right here we research a very easy 120V/220V smps LED driver circuit that can be used for driving high watt LEDs rated any place between 1 watt to 12 watts instantly from any domestic AC mains outlet.
The offered smps LED driver circuit is exceedingly adaptable and in particular fitted to driving high watt LEDs, in spite of this being a non-isolated topology does not give safety from electric shocks at the LED side of the circuit.
Aside from the above disadvantage, the circuit is perfect and is practically guarded from all feasible mains surge related hazards.
Even though a non-isolated configuration may appear a little unwanted, it reduces the constructor from winding complex primary/secondary sections on E-cores, since the transformer here is restored with a few easy ferrite drum type of chokes.
The main element here to blame for the performance of all the capabilities is the IC VIPer22A from ST microelectronics, which has already been specifically made for such small transformerless compact converter applications.
The circuit working of this 1 watt to 12watt LED driver may be known as presented under:
The input mains 220V or 120V AC is half wave repaired by D1 and C1.
C1 together with the inductor L0 and C2 make up a pie filter network for cacelling EMI disturbenaces.
D1 ought to be ideally changed to two diodes in series for preserving the 2kv spikes bursts genareated by C1 and C2.
R10 guarantees some level of surge security and works similar to a fuse throughout catatrophic circumstances.
As may be seen in the above circuit diagram, the voltage acroiss C2 is aplied to the interal mosfet drain of the IC at pin5 to pin8.
An inbuilt continuous current source of the VIPer IC provides a 1mA current to pin4 of the IC which is the Vdd pin of the IC.
At about 14.5V at Vdd, the curent sources gets turned OFF and causes the IC circuitry into an oscillatory mode or initiates pulsing of the IC.
The parts Dz, C4 and D8 turn out to be the circuit regulation network, where D8 charges C4 to the peak voltage in the freewheeling period and when D5 is forward one-sided.
Throughout the above measures, the source or the referance of the IC is set to about 1V below ground.
For an extensive info regarding the circuit information of the 1 watt to 12 watt LED driver, make sure you undergo the following pdf document offered by ST microelectronics.
WARNING: PLEASE ADD A SMALL PIECE OF HEATSINK WITH THE IC, OTHERWISE THE LEDS WILL START FLASHING ON/OFF RAPIDLY AS SOON AS THE IC BECOMES TOO HOT...THEREFORE MAKE SURE THE IC IS NOT ALLOWED TO BECOME HOT, BY ADDING A SUITABLE HEATSINK.