Therefore, the transistor cannot turn on. The requirements of a lighting application often dictate what type of circuit can be used, but if given the choice, the most efficient way to run high power LEDs is using a series circuit with a constant current LED driver. LED Driver Circuit. Sir is this circuit suitable for 9 watt and 12 watt As I want to use 9 parallel led of 1.2 watt and want to operate circuit at for 12 volt battery source led spec is 9- 10 Voff and 120 MA current please tell me what change is exaxtky required and Lm 338 required heat sink or suggest any other good ckt for different combination like strings of 4 led 3 volt Voff and 3 parallel series of this These capacitors are connected line to line and are designed for high voltage AC circuits. 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. So we consider 3.4volts as optimal voltage, and thus the 1 watt LED is running at 3.4×0.3=1.02 watts.

Finally here’s the simplest high power LED driver circuit diagram. Running a series circuit helps to provide the same amount of current to each LED. C1 together with the inductor L0 and C2 make up a pie filter network for cacelling EMI disturbenaces. the formula is: LED current in amps = 1.25 / R3 so for a current of 550mA, set R3 to 2.2 ohms you'll need a power resistor usually, R3 power in watts = 1.56 / R3 this circuit also has the drawback that the only way to use it with a micro-controller or PWM is to turn the entire thing on and off with a power FET. Bipolar junction transistors need base current and sufficient positive voltage to the collector in order to provide amplification. 230v LED Driver Circuit Principle. While the ratings of a 3 watt LED are Forward Voltage: VF 3.4V , Forward Current: 700mA . The main component is the X-rated AC capacitor, which can reduce the supply current to a suitable amount. The schematic of the LED driver circuit we will build is shown below: When the switch of the circuit is open, no current flows to the base of the transistor. The basic principle behind the 230V LED Driver circuit is transformer less power supply. For a 3 watt LED it's approximately 2.38 watts.