LED Driver manufacturers
LED driver is an electrical device which regulates the power to an LED or a string (or strings) of LEDs. An LED driver responds to the changing needs of the LED, or LED circuit, by providing a constant quantity of power to the LED as its electrical properties change with temperature. An LED driver is a self-contained power supply which has outputs that are matched to the electrical characteristics of the LED or LEDs. The power level of the LED is maintained constant by the LED driver as the electrical properties change throughout the temperature increases and decreases seen by the LED or LEDs. Without the proper driver, the LED may become too hot and unstable, therefore causing poor performance or failure.
Our LED driver is designed for energy efficient, long lasting, high quality, professional lighting applications. Including a wide range of switchable and dimmable LED drivers, they can be used as part of a simple standalone lighting system or bigger building management systems. Our driver is completely customizable based on user requirement. Our Drivers also offer dimming of LED light by means of pulse width modulation (PWM) circuits.
Classification of LED Drivers:
The classification of LED driver in the terms of LED power by driving method can be divided into two categories:
• constant current type:
A ) constant current drive circuit, the output current is constant, while the output DC voltage along with load resistance of different sizes in a certain range, the resistance of the load is small, the output voltage is low, the resistance of the load is bigger, the output voltage is higher also;
B) A constant current circuit is not afraid of a load short circuit, but forbidden to load a completely open.
C) Constant current driving circuit for driving the LED is ideal, but the relatively high price.
D) Should pay attention to the use of maximum current and voltage value, which limits the amount of use of the LED;
• constant voltage type or regulator type:
A) When the voltage regulator circuit parameters to determine the future, output voltage is fixed, and the output current with load change changes;
B) Voltage stabilizing circuit is not afraid of open load, but no load full short-circuit.
C) To power driving circuit for driving the LED, every string together with the appropriate resistance can make each string LED display brightness average;
D) The brightness will be affected by the rectifier and voltage change.
In constant voltage type, according to the circuit structure classification
(1) Resistance, capacitor step-down ways: through the capacitor, the flashing when in use, due to charge / discharge effect, through the LED instantaneous current great, easy to damage the chip. Vulnerable to the impact of network voltage fluctuation, low efficiency, low reliability of power supply.
(2) Through the resistance voltage dropping resistor step-down, caused by the voltage variation of the interference is larger, not easy to make a regulated power supply, a dropping resistor to consume the most energy, so the power supply power supply efficiency is very low, and the system reliability is low.
(3) The conventional transformer: small volume, weight, power on the power efficiency is very low, generally only 45% ~ 60%, so seldom use, reliability is not high.
(4) Power electronic transformer low efficiency, voltage range is not wide, generally 180~ 240V, wave interference.
(5) The RCC buck mode regulated switching power supply: wider scope, power efficiency is relatively high, generally can be 70% ~ 80%, the application is wide. The control mode of the frequency of oscillation is not continuous, the switching frequency is not easy to control and load voltage ripple coefficient is relatively large, abnormal load adaptability.
(6) PWM control mode switching power supply is mainly composed of four parts, an input rectifier filter part, the output rectifying filter part, PWM stabilizing control part, switching energy conversion part. PWM switching principle is the input voltage, internal parameters and the external load changes, the control circuit by the control signal with a reference signal based closed-loop feedback, regulation of main circuit of power device turn-on pulse width of the switching power supply, the output voltage or current is stable (that is, the corresponding power supply or a constant current power supply). Power efficiency is very high, generally can be 80% ~ 90%, the output voltage, current and stability. This general circuit are perfect protection measures, is of high reliability power supply.
LED driver is classified into two on the basis of input voltage provided:
• dc- dc driver
• ac – dc driver
DC-DC driver -A DC-to-DC converter is an electronic circuit which converts a source of direct current (DC) from one voltage level to another. It is a class of power converter. DC to DC drivers offer a method to increase voltage from a partially lowered battery voltage thereby saving space instead of using multiple batteries to accomplish the same thing. This conversion can be done using buck converter, boost converter and buck-boost converter. A buck converter is a voltage step down and current step up converter. A boost converter (step-up converter) is a DC-to-DC power converter with an output voltage greater than its input voltage. The buck–boost converter is a type of DC-to-DC converter that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is equivalent to a flyback converter using a single inductor instead of a transformer. Buck boost converter works in continuous mode and discontinuous mode which is fully related on the inductor.
AC-DC driver – AC-DC drivers are Switched Mode Power Supply (SMPS). This is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently Unlike a linear power supply, the pass transistor of a switching-mode supply continually switches between low-dissipation, full-on and full-off states, and spends very little time in the high dissipation transitions, which minimizes wasted energy. Ideally, a switched-mode power supply dissipates no power. The main advantage of the switching power supply is greater efficiency because the switching transistor dissipates little power when acting as a switch. Other advantages include smaller size and lighter weight from the elimination of heavy line-frequency transformers, and lower heat generation due to higher efficiency. AC – DC driver is classified into two on the basis of isolation
• Isolated drivers
All isolated topologies include a transformer, and thus can produce an output of higher or lower voltage than the input by adjusting the turn’s ratio. For some topologies, multiple windings can be placed on the transformer to produce multiple output voltages. Some converters use the transformer for energy storage, while others use a separate inductor. Different types of isolated drivers we commonly use are flyback, half bridge, H Bridge, forward and push-pull converter.
• Non Isolated drivers
Non-isolated converters are simplest, with the three basic types using a single inductor for energy storage which are buck, boost and buck boost. Different types of Non Isolated drivers we commonly use are buck, boost, buck-boost and SEPIC.
Advantages Of LED Drivers:
o High efficiency
o PWM dimming
o High Power Factor (PF> 0.9)
o Low Total Harmonic Distortion (THD< 15%)
o Overvoltage protection
o Small size
o Wide Wattage ranges