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LED power supply, also called LED driver, is a power supply that converts external primary power into secondary power required by LED lighting and converts power supply into specific voltage and current to drive LED to emit light. The input power of the LED power supply includes AC and DC, and the output power is generally a constant current that can change voltage with the change of LED forward voltage.
The components of LED power supply mainly include input filter devices, switch controllers, inductors, MOS switch tubes, feedback resistors, output filter devices, etc.
The main parameters of LED power supply
Input Voltage: The input voltage is indicated on the label of each LED driver. It is necessary to know the local rated grid voltage before using the LED driver. For example, in the United States, the input voltage is AC 110V and AC277V, and in Europe, the input voltage is AC 230V.
Power Factor: it is important for LED drivers.
(the more knowledge of power factor, you can visit Understanding the Power Factor in LED lighting systems)
Output current: When using a constant current LED driver, the PCB with LED current needs to be available as the output current of the power supply.
Output power: Selecting an LED driver to match the power of the LED lamps is necessary, the output power of the LED driver is best to be slightly larger than the rated value of the LED lamps.
Output Voltage: This voltage is a DC output in volts (V). For constant voltage power supplies, note that the output voltage needs to be at the rated voltage of your fixture.
Lifespan: LED driver life is usually measured in thousands of hours. Also known as MTBF (Mean Time before Failure), is to run the driver until its failure time. Generally, the rated parameters of the use of LED drivers can ensure its lifespan and reduce maintenance costs.
IP rating: Outdoor LED lighting always uses IP65, IP66, IP67 and IP68.
(Maybe you are interested in The knowledge of IP Rating for LED lights)
Classified by performance: there are three types, constant current, linear IC, and RC step-down power supply.
Constant current power supply: A constant output current is achieved by adjusting the switching frequency and duty cycle. It has the characteristics of high efficiency, small size and low power consumption. The switching constant current source is suitable for applications that require stable constant current output, such as LED lamps, electric vehicle chargers, etc.
Linear IC power supply: The linear IC power supply uses a linear regulator to achieve voltage reduction and controls the current output through feedback. It has the characteristics of low noise, low ripple and high stability, and is suitable for applications with high requirements for power supply noise and ripple, such as audio amplifiers, precision measuring instruments, etc. However, the efficiency of linear IC power supplies is low and requires a larger heat sink.
RC step-down power supply: The RC step-down power supply uses resistors and capacitors to achieve voltage reduction, which is suitable for lower power and simple applications. It has a simple design, low cost, and no switching frequency interference. The RC step-down power supply is suitable for some lower-power consumer electronic devices, such as mobile phone chargers, USB power supply devices, etc.
Classified by output power: output different power by the different power supplies, for example, 1W 2W 5W 10W 20W 30W 100W 200W etc.
Classified by output voltage: will output different voltage by different power supply, for example, DC4V, 6V, 12V，24V， 35V， 54V，108V etc.
Classified by shape structure: LED power supply can be divided into PCBA bare board and within shell.
Classified by security structure: LED drivers can be divided into Isolated drivers and non-isolated drivers, The Isolated driver is safer because it converts high voltage to low voltage through a transformer, preventing electrocution.
Classified by power factor: LED power supply can be divided into with power factor correction and without power factor correction. High PF power supplies are more efficient and provide better power savings.
Classified by the waterproof performance: there are waterproof and non-waterproof LED power supplies, and the waterproof driver is suitable for outdoor lamps.
Classified by the excitation method: LED power supply can be divided into self-excitation type and other-excitation type.
Classified by circuit topology: LED power supply can be divided into RCC, Flyback, Forward, Half-Bridge, Full-Bridge, Push-PLL, LLC, etc.
Classified by the conversion method: there are two types, transform AC to DC and transform DC to DC.
In summary, there are many different kinds of LED power supplies for different applications, as TopSun Lighting is a professional manufacturer of LED lights, so we are mainly talking about the constant current power supply used in LED lamps.
LED constant current power supplies can be divided into many types according to different working modes and application requirements. The following are some common LED constant current power supply categories and their main functions:
Linear constant current power supply: Linear constant current power supply uses linear regulation to achieve constant current output. It is simple and low-cost and is suitable for some low-power application scenarios.
Switching constant current power supply: Switching constant current power supply uses switching regulation to achieve constant current output. It has the characteristics of high efficiency and good stability and is suitable for high-power and high-brightness LED applications.
Multi-channel constant current power supply: Multi-channel constant current power supply can drive multiple LEDs or LED groups at the same time, and realize independent control of different LEDs by independently adjusting each current.
Dimming constant current power supply: Dimming constant current power supply can adjust the brightness of LED according to demand to realize the dimming function of light.
The main function of an LED constant current power supply is to provide a constant current to ensure that the LED lamp can work normally and achieve the expected brightness and life. It can also protect LEDs to avoid current overload and overheating and improve the stability and reliability of LEDs.
The working principle of LED constant current power supply is based on a negative feedback control mechanism, which continuously adjusts the output current to keep it consistent with the set constant current value.
Current detection: The LED constant current power supply monitors the output current in real-time through the current detection loop, and compares the monitored current value with the set constant current.
Error amplification and comparison: If the detected current is inconsistent with the set constant current, the error amplifier will amplify the error signal and compare it with the reference voltage to generate a control signal.
Control and regulation: According to the control signal, the constant current control circuit will adjust the power supply output so that the output current is close to the set constant value. PWM (pulse width modulation) technology is usually used to control the conduction time of the switching element, to achieve precise regulation of the output current.
Stable output: The LED constant current power supply stably provides constant current to the LED through the above control and regulation process. Regardless of the influence of input voltage changes, temperature fluctuations or other factors, the LED constant current power supply can maintain the stability of the output current to ensure the normal operation of the LED.
The main function of the LED constant current power supply is to provide a constant current to ensure that the LED can work properly and achieve the expected brightness and life. It also protects the LED from problems such as current overload and overheating and improves the stability and reliability of the LED.
Choosing the right LED driver is essential to ensure the performance and life of LED lamps. Here are some key factors for choosing an LED driver:
Power requirement: You need to determine the power requirement of the LED lamp being driven first. Then select the corresponding driver capacity based on the total power of the lamp to ensure that the driver can meet the required power.
Input voltage: Understand the standard grid voltage range in your area and select a driver that can adapt to this range. Generally speaking, drivers on the market have a wide input voltage range, such as 100-240VAC.
Output current and voltage: According to the characteristics and requirements of the LED lamp, select the appropriate output current and voltage. Ensure that the driver can provide a stable current and a voltage that meets the requirements of the LED lamp.
Dimming function: If the dimming function is required, select a driver that supports the corresponding dimming method (such as PWM, 0-10V, etc.).
Protection level and durability: According to the environmental conditions and usage scenarios, select a driver with an appropriate protection level and good durability to ensure its reliable operation in harsh environments.
Quality and certification: Choose LED drivers with high brand awareness, reliable quality and relevant certifications (such as CE, UL, etc.) to ensure safety, reliability and compliance with relevant standards.
Power factor and harmonic distortion: Pay attention to the power factor and harmonic distortion level of the driver, and choose products with higher power factor and lower harmonic distortion to reduce pollution to the power grid.
The warranty period and after-sales service: Consider the warranty period and after-sales service of the driver, and choose suppliers that provide good technical support and after-sales service.
