In electronics, an LED circuit or LED driver is an electrical circuit used to energy a gentle-emitting diode (LED). The circuit must present enough current to light the LED at the required brightness, however should restrict the present to prevent damaging the LED. The voltage drop across a lit LED is roughly constant over a variety of working present; therefore, a small increase in applied voltage enormously increases the current. Very simple circuits are used for EcoLight home lighting low-power indicator EcoLight LEDs. Extra advanced, present supply circuits are required when driving excessive-energy LEDs for long-life LED illumination to achieve appropriate current regulation. The only circuit to drive an LED is thru a series resistor. It is often used for indicators and digital displays in many consumer appliances. Nevertheless, this circuit shouldn't be power-environment friendly, because vitality is dissipated within the resistor as heat. With a sufficiently high provide voltage, multiple LEDs in series may be powered with one resistor.

The voltage versus present characteristics of an LED is much like any diode. Current is roughly an exponential operate of voltage based on the Shockley diode equation, and a small voltage change could lead to a big change in current. If the voltage is under or equal to the threshold no present flows and the result is an unlit LED. If the voltage is just too high, the current will exceed the maximum score, long-life LED overheating and potentially destroying the LED. LED drivers are designed to handle fluctuation load, providing sufficient current to attain the required brightness while not allowing damaging ranges of current to circulate. Drivers may be constant present (CC) or fixed voltage (CV). In CC drivers, the voltage adjustments while the present stays the same. CC drivers are used when the electrical load of the LED circuit is both unknown or fluctuates, for instance, a lighting circuit the place a variable number of LED lamp fixtures may be installed. This will encourage the current to extend.

An lively constant present supply is commonly used for high power LEDs, stabilizing gentle output over a variety of input voltages which might increase the helpful life of batteries. Energetic constant present is usually regulated using a depletion-mode MOSFET (metal-oxide-semiconductor area-impact transistor), which is the best present limiter. Low drop-out (LDO) constant current regulators additionally permit the overall LED voltage to be a higher fraction of the ability supply voltage. Switched-mode energy supplies (e.g. buck, long-life LED increase, and buck-boost converters) are utilized in LED flashlights and household LED lamps. Power MOSFETs are sometimes used for switching LED drivers, EcoLight which is an efficient answer to drive excessive-brightness LEDs. Energy integrated circuit (IC) chips are broadly used to drive the MOSFETs immediately, without the necessity for long-life LED added circuitry. Sequence resistors are a simple strategy to stabilize the LED present, but energy is wasted in the resistor. Miniature indicator LEDs are usually driven from low voltage DC via a current-limiting resistor.

Currents of two mA, 10 mA and 20 mA are frequent. Sub-mA indicators could also be made by driving extremely-shiny LEDs at very low present. A hundred μA are nonetheless sensible. In coin cell powered keyring-type LED lights, the resistance of the cell itself is usually the only current limiting gadget. LEDs with built-in sequence resistors can be found. These may save printed circuit board space, EcoLight solutions and are particularly helpful when building prototypes or populating a PCB in a way aside from its designers meant. However, the resistor worth is set on the time of manufacture, removing certainly one of the important thing strategies of setting the LED's intensity. Strings of a number of LEDs are usually connected in series. In one configuration, EcoLight the source voltage must be larger than or equal to the sum of the person LED voltages; sometimes the long-life LED voltages add as much as around two-thirds of the provision voltage. A single current-limiting resistor may be used for long-life LED each string.