First of all, let's talk about what is the LED driving power? It can convert the power supply into a specific voltage and current to drive the LED light voltage converter. Under normal circumstances: The LED drive power input includes high-voltage industrial frequency AC (ie, mains), low-voltage DC, high-voltage DC, low-voltage high-frequency AC (such as the output of electronic transformers) and so on. The output of the LED driver is mostly a constant current source that changes the voltage as the LED forward voltage drop changes.
The LED power core components include switch controllers, inductors, switching elements (MOSfets), feedback resistors, input filter components, output filter components, and the like. According to different occasion requirements, there must be input over-voltage protection circuit, input under-voltage protection circuit, LED open circuit protection, over-current protection circuit.
LED drive power features
(1) High reliability
In particular, the driving power source of LED street lights is installed at a high altitude, which is inconvenient to maintain and costs a lot for maintenance.
(2) High efficiency
LED is an energy-saving product, and the efficiency of driving power is high. It is very important for the heat dissipation of the power supply installed in the lamp. The efficiency of the power supply is high, its power consumption is small, and the heat generated in the lamp is small, which also reduces the temperature rise of the lamp. It is beneficial to delay the decay of the LED.
(3) High power factor
The power factor is the grid's load requirements. Household appliances below 70 watts are generally not mandatory. Although the single power device with low power has a low power factor, it has little impact on the power grid. However, the large amount of lighting used at night and the similar load is too concentrated can cause serious pollution to the power grid. For a 30-watt to 40-watt LED driver, it is said that in the near future, there may be certain indicators of power factor requirements.
(4) Driving method
There are two types of traffic now: one is a constant voltage source for multiple constant current sources, and each constant current source supplies power to each LED individually. This way, the combination of flexible, all the way LED failure, does not affect the work of other LEDs, but the cost will be slightly higher. The other is a direct constant current supply with LEDs running in series or in parallel. Its advantage is that the cost is lower, but the flexibility is poor, but also to solve a certain LED failure, does not affect the operation of other LED. Both forms coexist for a period of time. Multiple constant current output power supply methods will be better in terms of cost and performance. It may be the mainstream direction in the future.
(5) Surge protection
The ability of the LED to withstand surges is relatively poor, especially against reverse voltage capability. It is also important to strengthen this protection. Some LED lights are installed outdoors, such as LED street lights. Due to the start of the grid load and the induction of lightning strikes, various surges can be invaded from the grid system, and some surges can lead to LED damage.
(6) Protection function
In addition to the conventional protection function, it is better to increase the LED temperature negative feedback in the constant current output to prevent the LED temperature from being too high; it is necessary to comply with safety regulations and electromagnetic compatibility requirements.
Compared with the overall constant current, although the disadvantages are more, the cost is higher. But it can really protect the LED and extend the life of the LED, so the constant flow is the future trend.
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Classified by driving method
(1) Constant current
The output current of the constant current drive circuit is constant, but the output DC voltage varies with a certain range with the magnitude of the load resistance, the load resistance is small, the output voltage is low, the greater the load resistance, the output voltage is also The higher the
The constant current circuit is not afraid of load short circuit, but the load is strictly prohibited;
The constant current drive circuit drives the LED is ideal, but relatively high price;
Pay attention to the maximum withstand current and voltage used, which limits the number of LEDs used.
(2) Regulated
When the parameters in the voltage regulator circuit are determined, the output voltage is fixed, and the output current changes with the increase or decrease of the load;
The voltage regulator circuit is not afraid of the load open circuit, but the load is strictly prohibited;
With a constant voltage driver circuit to drive the LED, each string needs to add an appropriate resistor to allow each LED to display average brightness.
The brightness is affected by the voltage change from the rectification.
Boom Lift
Boom lift is widely used in municipal, power, street lamps, highways, docks, advertising, gardens, residential properties, factories and mines, workshops and other industries. High altitude operation can be carried out across obstacles. When the platform is lifted to any position, it can work while walking. The structure is compact and the steering is flexible. The width of the site can ensure that the equipment can enter the narrow channel and the crowded working area. Standby power unit, which can operate the working platform to reset, convenient transportation mode, and can be towed to any place. Easy to identify operation panel, multiple mechanical, electrical and hydraulic safety protection, advanced integrated hydraulic and electrical integrated system.
A multifunctional and multipurpose working device. Through the boom front-end bracket, the lifting device or manned platform can be quickly installed to realize the functions of material lifting, lifting and manned high-altitude operation, and provide an interface for the expansion of the working device and the rapid switching of various working devices.
It is easy to operate, easy to use and has a large working surface. In particular, it can be overhanging operation, cross certain obstacles or lift at one place, and can carry out large-scale multi-point lifting operation, which greatly improves the working efficiency.