This section provides overview, applications, and principles of led drivers. Also, please take a look at the list of 8 led driver manufacturers and their company rankings.
A LED driver is an integrated circuit (IC) that stably drives and safely controls LEDs. LEDs emit varying amounts of light depending on the current value, and the current value varies depending on the color of the LED, so stable driving requires highly accurate current control. For this reason, control by a constant-current circuit is extremely important, and this is the main function of LED driver.
As the name suggests, LED drivers are used to drive and control LEDs. In recent years, however, LEDs with low power consumption and long life have become the mainstream for lighting fixtures instead of fluorescent lamps, and many LED drivers are sold for lighting applications.
Lighting fixtures often require brightness control, and especially in the case of LED drivers, strict current control is important. Recently, there are many needs to switch to LEDs for lighting from the viewpoint of promoting energy conservation, as typified by the SDGs, which also requires highly efficient lighting.
In addition, LEDs are also being used as indicator lamps in home appliances and automobiles, and LED drivers dedicated for these applications are being developed.
LED stands for "Light Emitting Diode" and refers to a semiconductor device that emits light when a forward bias is applied to its PN junction. The LED drivers incorporates a constant-current generation circuit integrated on an IC, and depending on the product, a PWM control circuit and SPI or I2C interface are also built in.
In general, the amount of light emitted by an LED varies with the amount of current applied, but the color (emission wavelength) of the LED also changes in accordance with the current value. In addition, too much current will have a significant impact on the life of the device. Therefore, it is necessary to accurately control and apply the optimum current value for the LEDs used, taking into consideration the light intensity, hue, and luminous efficiency according to the luminous characteristics of the LEDs, and LED drivers are used for this purpose.
For single function LED drivers, a combination of discrete Zener diodes, MOSFETs, etc. can be used, but when multiple LEDs are connected in series or parallel and LEDs of various colors with different optimum current values are to be operated in combination, ICs are used to meet the required specifications.
There are various types of drivers used in LED drivers, such as linear type and step-up/step-down type.
This circuit type does not incorporate a DCDC converter, but uses a MOSFET and resistors for constant-current control. The single function allows for miniaturization and cost reduction, but has the disadvantage of high MOSFET loss at high input voltages.
This circuit type can operate with high efficiency by suppressing the increase in loss during the step-up and step-down functions that can accommodate an increase in the number of LED stages. However, since the circuit is complex and the cost is high, LED drivers that can only support boost or buck are also widely used, depending on the application.
PWM control is widely used in LED drivers for dimming. This is because the method of adjusting the driver's DC current value has the problems of heat generation due to lower efficiency and wavelength change (emission color change) accompanying the current change.
In the case of PWM-control led drivers, the apparent voltage can be varied by adjusting the width of rectangular pulses (duty ratio), and there is no power loss associated with dimming. In such a driver, LED dimming is often performed with a semi-fixed resistor. If the semi-fixed resistor is removed and replaced with a volume, LED drivers that can be adjusted with the volume can be realized.
The brightness of LEDs is proportional to the duty cycle of the pulse, but if the ON/OFF cycle is too slow, it can be discerned by the human eye, leading to flickering of the lighting. Therefore, care must be taken with the set frequency of the PWM control.
It is common for several LEDs of different colors to be used in home appliances and automobile instrument panels. Depending on the type and quantity of LEDs to be controlled, IC connection may be difficult if only analog signals for ON/OFF and bias values are exchanged. In such cases, a serial interface with digital control over a few wires, such as SPI or I2C, is used.
LED drivers with serial interface functionality include large-scale products capable of controlling several hundred LEDs simultaneously, as well as products capable of controlling brightness and diagnostics for each channel.
*Including some distributors, etc.
Sort by Features
Sort by Area
This is the version of our website addressed to speakers of English in the United States. If you are a resident of another country, please select the appropriate version of Metoree for your country in the drop-down menu.