LED injection molding modules are often used in our daily life. Advertising light boxes in bus stations, subways, airports, and logos for corporate logos all require LED injection molding module lights as light sources. LED injection molding modules must be driven by professional power supplies, so how is the power supply of LED injection molding modules classified?

1. LED injection molding module power supply can be divided into two categories according to the driving method:

A. Regulator:

1. After the voltage regulator circuit determines various parameters, the output is a fixed voltage, but the output current changes with the increase or decrease of the load.

2. Although the voltage stabilizing circuit is not afraid of load open circuit, it is strictly forbidden to completely short circuit the load

3. The voltage change after rectification will affect the brightness of the LED injection molding module

4. In order to make each string drive the LED injection module with a voltage stabilizing circuit to display uniform brightness, it is necessary to add a suitable resistor.

B. Constant flow:

1. It is ideal to drive the LED injection molding module with a constant current drive circuit, but the disadvantage is that the price is high

2. Although the constant current circuit is not afraid of short circuit of the load, it is strictly forbidden to open the load completely.

3. The current output by the constant current drive circuit is constant, but the output DC voltage varies within a certain range with the load resistance.

4. To limit the number of LED injection molding modules, because it has the maximum withstand current and voltage values

2. LED injection molding module power supply can be divided into six categories according to the circuit structure:

1. Step-down of conventional transformer:

The advantage of this type of power supply is its small size, but the disadvantage is that it is heavy in weight and has low power efficiency, generally 45% to 60%. Because of its low reliability, it is rarely used.

2. Capacitor step-down:

The LED injection molding module in this way is easily affected by the voltage fluctuation of the power grid, and the power supply efficiency is low. The instantaneous current passing through the LED injection molding module is extremely large, which is easy to damage the chip.

3. Step-down of electronic transformer:

The disadvantage of this power supply structure is that the conversion efficiency is low, the voltage range is narrow, generally 180~240V, and the ripple interference is large.

4. Resistance drop:

The power efficiency of this power supply method is very low, and the reliability of the system is also low. Because the circuit is stepped down by a resistor, it is greatly disturbed by the change of the grid voltage, and it is not easy to make a regulated power supply, and the step-down resistor itself consumes a large part of the energy.

5. RCC step-down switching power supply:

The advantages of this method of LED injection molding module power supply are that the voltage regulation range is relatively wide and the power supply efficiency is relatively high, generally 70%~80%, which is widely used. The main disadvantages are that the switching frequency is not easy to control, the load voltage ripple coefficient is large, and the load adaptability is poor in abnormal conditions.

6. PWM controlled switching power supply:

At present, the LED injection molding module power supply designed by PWM control method is ideal, because the output voltage or current of this switching power supply is very stable. The power conversion efficiency is extremely high, generally as high as 80%~90%, and the output voltage and current are very stable. The LED power supply in this way is mainly composed of four parts: the input rectifier and filter part, the output rectifier and filter part, the PWM voltage regulation control part, and the switching energy conversion part. Moreover, this circuit has perfect protection measures and belongs to high reliability power supply.

Nine performance characteristics and requirements of LED injection molding module drive power

According to the electricity consumption rules of the power grid and the characteristic requirements of the LED injection molding module power supply, the following nine performance characteristics should be considered when selecting and designing the LED injection molding module power supply:

1. High reliability, especially like the driving power supply of street lamps, is installed at high altitude, maintenance is inconvenient, and the maintenance cost is also large.

2. High efficiency, LED injection molding module is an energy-saving product, and the efficiency of the driving power supply is high. It is especially important for the structure where the power supply is installed in the luminaire. Because the luminous efficiency of the LED injection molding module decreases with the increase of the LED temperature, the heat dissipation of the LED injection molding module is very important. The efficiency of the power supply is high, its power loss is small, and the heat generated in the lamp is small, which reduces the temperature rise of the lamp. It is beneficial to delay the light decay of the LED injection molding module.

3. High power factor Power factor is the requirement of the grid for the load. Generally, there are no mandatory indicators for electrical appliances below 70 watts. Although the power factor of a single electrical appliance with low power is low, it has little impact on the power grid, but everyone turns on the lights at night, and the same load is too concentrated, which will cause serious pollution to the power grid. For 30 watts to 40 watts of LED drive power, it is said that in the near future, there may be certain index requirements for power factor.

4. There are two types of driving methods: one is a constant voltage source for multiple constant current sources, and each constant current source independently supplies power to each LED injection molding module. In this way, the combination is flexible, and the failure of one LED injection module will not affect the work of other LED injection modules, but the cost will be slightly higher. The other is direct constant current power supply, and the LED injection molding modules run in series or in parallel. Its advantage is that the cost is lower, but the flexibility is poor. It also needs to solve the failure of a certain LED injection molding module without affecting the operation of other LED injection molding modules. These two forms coexist for a period of time. The multi-channel constant current output power supply method will be better in terms of cost and performance. Maybe the mainstream direction in the future.

5. Surge protection The ability of LED injection molding module to resist surge is relatively poor, especially the ability to resist reverse voltage. Strengthening this protection is also important. Some LED injection molds are assembled outdoors, such as street lights. Due to the start-up of the grid load and the induction of lightning strikes, various surges will invade from the grid system, and some surges will cause damage to the LED injection molding module. Therefore, the drive power supply of the LED injection molding module must have the ability to suppress the intrusion of surges and protect the LED injection molding module from being damaged.

6. Protection function In addition to the conventional protection function of the power supply, it is better to increase the negative feedback of the LED temperature in the constant current output to prevent the temperature of the LED injection molding module from being too high.

7. In terms of protection, the lamp is installed outside, the power supply structure should be waterproof and moisture-proof, and the shell should be resistant to sunlight.

8. The life of the driving power supply should be matched with the life of the LED injection molding module.

9. To comply with safety regulations and electromagnetic compatibility requirements.