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What Are the Common Terms of Led Drive Power Supply?

Apr. 28, 2020


1. Isolation and non-isolation

At present, in the general constant current led driver led driver market, there are non-isolated design and isolated drive power. The non-isolated design is limited to double-insulated products, such as bulb replacement products, where the LED and the entire product are integrated and sealed in non-conductive plastic, so there is no risk of electric shock for the end user. The secondary products are all isolated and relatively expensive, but where users can access the LED and output wiring (usually in the case of LED lighting and street lighting applications), this product is essential.

The LED driving power supply with isolation transformer or electrical isolation means that the LED can be directly touched by hand without electric shock. Although the LED driving power without isolation transformer can still achieve some mechanical insulation by means of the protective shell, the LED at this time cannot be directly touched during operation. Therefore, isolation has greatly improved compared to non-isolated security factors.

2. The original plan

The primary side scheme is to control the output power and current completely on the AC primary side, which can achieve 5% constant current accuracy, and the secondary side only needs a simple output circuit. The primary side mainly relies on the feedback of the auxiliary side to control the output voltage, and the current limiting resistor controls the primary side current, while multiplying the turns ratio to control the accuracy of the output current. The primary-side solution inherits various advantages of the isolated flyback circuit, and at the same time has a simple structure, can achieve small size and low cost, and has now become the mainstream driver.

The problem of constant current accuracy on the primary side: Because the production accuracy of the transformer is difficult to control, the primary current scheme has a large output current drift when using a low-quality transformer. Therefore, the primary side scheme improves the secondary side constant current control circuit by improvement, so that although it is more complicated than the ordinary primary side scheme, compared with the flyback scheme, the optocoupler can still be omitted, and the system is cost-effective.

3. Resistance-capacitance buck

Use the impedance of the capacitor under AC to limit the input current, so as to obtain the DC level to power the LED. This driving method has a simple structure and low cost, but the input non-isolated scheme has potential safety hazards. Moreover, the conversion efficiency is very low and constant current control cannot be achieved.

4. High power factor

The power factor is the load requirement of the power grid. Generally, there is no mandatory index for electrical appliances under 70 watts. Although the power factor of a single consumer with low power is a little low, it has little effect on the power grid, but everyone lights up at night, and similar loads are too concentrated, which will cause serious pollution to the grid. For LED drive power of 30 watts to 40 watts, it is said that in the near future, there may be certain index requirements for power factors.

5. High reliability

Especially like the LED street lamp power supply, it is installed at high altitude, which is inconvenient to maintain and the cost of maintenance is also large.

6. High efficiency

LEDs are energy-saving products, and the efficiency of CE LED drivers is higher. It is particularly important for the structure where the power supply is installed in the lamp. Because the luminous efficiency of LEDs decreases as the temperature of LEDs increases, the heat dissipation of LEDs is very important. The efficiency of the power supply is high, its power consumption 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 LED.

30w Led Driver

30w Led Driver

7. Surge protection

The ability of LED to resist surge is relatively poor, especially the ability to resist reverse voltage. It is also important to strengthen protection in this regard. Some LED lights are installed outdoors, such as LED street lights. Due to the induction 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. Therefore, the 30w LED driver must have the ability to suppress the intrusion of the surge and protect the LED from being damaged.

8. Protection

Protection mainly refers to external power supply, such as LED waterproof power supply, this power supply can meet the requirements of waterproof and moisture-proof, if you use outdoor street lamp floodlight housing, it should also be resistant to light.