Classification of Led Lights:
Fluorescent light, panel light, down light, ceiling light, spot light, track light, etc Take a look at the directory of the index above, the lights are all on it, so be familiar with them.)

Classification of common lamp beads:

1. In-line low-power specifications include: straw hat/helmet, round head, concave, oval, tombstone type (2*3*4) bullet head, flat head, (3/5/flat head/bread type) piranha, etc.

2. SMD patches are generally divided into (3020/3528/5050, which are front-emitting)/1016/1024, etc. These are side-emitting light sources. The name is named according to the specifications of the patch. For example, 3020 is 30mm*20mm. .

3. High-power LEDs cannot be classified into SMD series, their power and current usage are different, and the optoelectronic parameters are very different. If a single high-power LED light source does not have a heat dissipation base (usually a hexagonal aluminum base), its appearance is not much different from that of ordinary patches. However, it is essentially different from SMD patches in terms of use conditions/environments/effects.

The voltage of a single lamp bead: the voltage of the general lamp bead is 2.8-3.6vf, and the middle value is 3.3vf when calculating in series and parallel.

Power classification:
According to the different output characteristics, it is divided into: constant voltage series (CV), constant current series (CC) (constant voltage refers to constant voltage output, constant current output, and one of them is the complementary power supply of constant voltage + constant current)

According to the different input characteristics, it is divided into: ordinary series, high power factor series (high power factor mainly refers to power factor, and a detailed introduction to this parameter will be given later)

According to different uses, it is divided into: waterproof series, non-waterproof series (this does not need to be explained, everyone understands)

According to different circuit structures, it is divided into: isolation series, non-isolation series (the difference between isolation and non-isolation here is mainly whether there is a transformer, because we know that the household voltage is 220v sinusoidal alternating current, and the isolated power supply design idea is to step down first through the transformer Re-rectification, this design can distinguish high voltage and low voltage, which is more advantageous than the power supply without transformer. For example, the output of our LED power supply is DC safe voltage, which can be directly touched by people (except for high-power power supplies), even if the low-voltage part is broken, It will not leak electricity, but the use of non-isolated ones is likely to cause electric shock)

According to different control methods, it is divided into: dimmable series, non-dimming series (the parameters of dimming will be introduced in detail later)

Series and Parallel:

First, confirm the sum of the forward voltage of each string of LEDs, plus the voltage drop of the constant current driver is about 2V

LED operating voltage per string = 3.5V X 12 pieces = 42V

Drive circuit voltage = 42V + 2V = 44V

LED current = 0.7A X 4 series parallel = 2.8A

Driver circuit wattage = 44V X 2.8A = 123.2W

LED power supply wattage/voltage selection should be greater than and closest to the desired wattage/voltage

First select the LED power supply based on the 150W/48V demand, and then confirm whether the actual wattage of the drive circuit meets the load requirement of PF>0.9 (123.2W /150W = 82.13%>75%)

For example, in this question, you can choose the CLG-150A-48 model and adjust the output voltage to 44V or apply it directly without adjusting the output voltage.

Note: Generally, the Vf voltage of the same batch of LEDs may be in a range (such as 3.4~3.6V), and each LED is different, so the influence of this difference should be considered in the selection of the power supply

PWM dimming:

The dimming methods of MW dimming power supply mainly include control signal (resistance/voltage/PWM) dimming current dimming and thyristor AC (phase shifting) voltage dimming.

1. Products that control signal dimming include ELN, LPF-XD, HLN-XB, HLP, HLG-XB, HVG(S)-XB, etc. Its adjustment range is 5/15% ~ 100/103% of rated current. There are three options for the control signal as follows

a). Potentiometer (100kΩ/1～2kΩ variable resistance, adjust the current value through the LED by changing the resistance value of the potentiometer

b).1～10V DC voltage, adjust the current value through the LED by changing the control voltage

c). PWM signal (pulse amplitude 10V, f: 100～3000Hz, duty ratio: 0～100%). By changing the duty cycle to adjust the average current value through the LED, this control method can keep the color temperature of the LED unchanged

Some specifications also have timing control function (such as HLG/HVG-D).

The dimming power supply with control signal dimming has good electromagnetic compatibility (EMS), and the dimming range is wide and smooth.

2. The thyristor AC (phase shift) voltage regulation and dimming products include PCD series. (The matching thyristor dimmer has a specified model, and other types of dimmers cannot guarantee the dimming effect). The thyristor voltage regulating dimming power supply has poor performance, and is generally used in the transformation of old systems and low-cost applications.

Power input voltage:
For example: 88-264V/AC, as long as the electricity voltage of each country is within this range, but it is worth noting that the frequency is 50 Hz in our country, so other countries may be different, so pay attention to this.

Power supply output voltage/current/power:
The output is generally a range. If the voltage required by the user is within this output range, it is fine. Of course, the output power must be enough.

Mains power factor:
The cosine of the phase difference (Φ) between the voltage and the current is called the power factor. Conceptual things are really troublesome. If you let a liberal arts person see it, you will definitely see that your head will explode or you will not understand. Let me put it this way. There must be voltage, voltage alone is not enough, but also current, because the voltage delivered by the power plant is a little slower than the current, so it leads to some complex concepts, but we are not going to learn this, then we just need to Knowing that the power factor is probably an efficiency thing, the closer the value is to 1, the better the effect. There is a parameter called PFC behind it. What is it used for? It is used to improve the power factor, you will know when you see the parameters behind.

surge:

Surge voltage/current: 1. Input surge current means that the input loop of the power supply has a large surge current during cold start due to its capacitive characteristics, generally 20~60A, and the time does not exceed 20mS. The inrush current of the power supply in the hot state is slightly smaller, and frequent switching of the machine should be avoided to reduce the frequent impact of the power supply and distribution system by high current and injury. 2. The surge withstand capability of the power supply refers to the surge voltage withstand capability of the input terminal (L to N or GND). The surge voltage withstand capability of a 220V power supply is generally 300Vac/5S.

Current accuracy

current harmonics

Output ripple:

Ripple voltage: The ripple voltage of the switching power supply contains two components, one is the double frequency component of the input power supply, with a larger amplitude, and the other is the switching frequency component with a higher frequency (up to several kHz) and its amplitude is smaller (Also known as noise signal). The two components have different effects on different loads. Usually, only the component with the greater impact is taken to deal with it. It is not common for the two components to have a significant impact on the load at the same time.

Safety:

Safety regulations are safety regulations, in order to prevent 6 dangers caused by poor materials, design errors, and misuse of parts (the six dangers are: 1) electric shock; 2) energy hazards; 3) fire hazards; 4) Mechanical and thermal damage; 5) Radiation; 6) Chemical damage. ) and established standards.

The safety regulations include two major product certification directions of the American system and the IEC system.

The American system is represented by UL and CSA (UL/CSA60950-1-03),

European IEC system (EN/IEC60950-1,

my country's GB4943-2001 is equivalent to IEC60950-1999) with CB as the general direction,

The most famous and the EU's CE certification is the most influential. Common safety certifications include CB, CE, UL, FC, TUV, IEC, CAS, CCC, etc.

The safety standards of UL and VDE are essentially different. The UL standard is more concerned with preventing the risk of fire, while the VDE standard is more concerned with the safety of operators. For power supplies, VDE is the most stringent electrical safety standard.

EMC:
EMC is the electromagnetic compatibility requirements of products. EMC=EMI+EMS, EMI is the electromagnetic interference limitation requirement of the product, and EMS is the requirement of the product's resistance to electromagnetic interference. These two requirements are to make the product and the surrounding products compatible with each other in terms of electromagnetic interference and not interfere with each other. The electromagnetic impact of EMC on products is mainly assessed from the EMS resistance to electromagnetic interference, including electrostatic discharge, electrostatic field, radio radiation, pulsed radiation, lightning, radio conduction, power frequency electromagnetic field, power transient resistance, etc. And from the assessment of EMI limit interference, including radio emission/conduction, voltage flicker, harmonics and other interference limits.

PFC

PFC (Power Factor Correction) power factor correction is mainly to improve the ratio of the effective power to the apparent power at the input end of the power supply. Generally, for models without PFC lines, the power factor at the input end is only 0.4~0.6, while those with active PFC lines can reach more than 0.95. The correlation formula is as follows:

Apparent Power = Input Voltage x Input Current (VA)

Active Power = Input Voltage x Input Current x Power Factor (W)

From the point of view of environmental protection: the power plant of the electric power company must generate electric energy greater than the apparent power, so that its generator set can stably supply the market electric energy demand, and the actual use of electric energy is the effective power. If the power factor is 0.5, it means that the generator set generates more than 2VA of electricity to safely supply the demand of 1W of electricity, and its energy operation efficiency is poor. Conversely, if the power factor is improved to 0.95, as long as the generator set of the power company generates more than 1.06VA of electricity, there is no problem in supplying 1W of electricity, and the energy operation efficiency is better.

MTBF:
Mean time between failures (MTBF) and life expectancy (Life Cycle) are important indicators of product reliability. The so-called MTBF (Mean Time Between Failure) is the expected value of reliability estimation, which refers to the average time when the reliability of a product drops to 36.8% after continuous operation for a period of time. MEAN WELL MTBF currently uses the MIL-HDBK-217F standard to estimate the expected value of product reliability (excluding fans) by the part counting method, which refers to the probability that the product can still work normally after continuous use for the counted time. is 36.8% (e-1=0.368). If the product is used continuously for twice the counted MTBF, the probability that it will still work properly is 13.5% (e-2=0.135).

The Life Cycle refers to the temperature rise of the electrolytic capacitor of the product under full load conditions, and the reference value for calculating the life of the electrolytic capacitor. For example, product SP-750-12 MTBF=769.3K hours, capacitor C108 Life Cycle=202.2K hours (Ta=45°C).

Ageing:
It is equivalent to the product coming out and testing whether it can work normally. This test does not mean that the test is OK and it is over, but a long-term test to see if the product can be stable, even in a room with abnormal temperature. The test, as for how long it will take, seems to be at least four hours, depending on the situation.