The technical requirements for LED street lights mainly include constant current accuracy, power supply voltage and current design, series-parallel configuration of the power board, isolated vs. non-isolated power selection, LED board and power supply matching, series-parallel connection and power factor, electrolytic capacitor configuration, and power supply efficiency. Details are as follows:
Constant Current Accuracy
LED street lights must maintain constant current accuracy to counteract the effects of environmental factors such as temperature and voltage fluctuations on the working current. Some power supplies on the market have poor constant current accuracy, with errors as high as ±8%, whereas the overall requirement should be controlled within ±3% to ensure the stability and service life of LED street lights.
Power Supply Voltage and Current Design
The working voltage of an LED is typically between 3.0–3.5V, with most operating at 3.2V, so calculations based on 3.2V are reasonable. The total voltage for N LEDs in series = 3.2 × N.
The working current design of the LED street light power supply must account for heat generation. For example, if the LED's rated working current is 350mA, designing it at 320mA is more ideal, as it reduces heat generation and allows more electrical energy to be converted into visible light energy.
Series-Parallel Configuration of the Power Board
For LED street light power boards with a wide input voltage range (AC85–265V), the series-parallel configuration is important. Wide voltage ranges should be avoided where possible; it's better to separate AC220V and AC110V to ensure power supply reliability.
Wide-voltage solutions such as APFC (Active Power Factor Correction) can be used in special cases - first using an L6561/7527 to boost the voltage to 400V, then stepping it down to match the level of two switching power supplies.
Isolated vs. Non-Isolated Power Selection
For a standard isolated power supply rated at 15W, if placed inside an LED street light power housing, the transformer would be too large to fit. Isolated designs generally max out around 15W; beyond that, they become rare and very expensive.
Non-isolated designs are more mainstream, as they can be made smaller - as thin as 8mm in height. If proper safety measures are implemented and space allows, isolated power supplies can also be used.
LED Board and Power Supply Matching
When designing the LED board, customers should communicate with the power supply manufacturer to customize it according to power requirements, or manufacture the power supply themselves to ensure a proper match between the power supply and the LED board.
Choose an appropriate series-parallel configuration so that the voltage and current across each LED are consistent, maximizing power supply performance. Avoid situations where the current is too high and voltage too low, or current too low and voltage too high, as these can cause excessive heat, low efficiency, or insufficient input voltage range.
Series-Parallel Connection and Power Factor
For LED street light power supplies, it's advisable to keep the number of LEDs in series under 45 to achieve a higher power factor.
For isolated power supplies, the number of series connections is related to the number of secondary winding turns, and the required power output must meet output power demands.
Electrolytic Capacitor Configuration
Electrolytic capacitors are used to maintain voltage and minimize AC ripple at the output. The capacitance at the low-voltage end should not be too small - a ratio such as 1μF per 1.5mA relative to output current should be appropriate; otherwise, the LED may flicker.
For non-isolated designs, the input-end high-voltage electrolytic capacitor selection is the same as for isolated designs, with the output end typically at 1μF per 6mA. For dimmable LED power supplies, the output electrolytic capacitor should be around 1μF per 0.5mA.
Power Supply Efficiency
The greater the difference between input power and output power, the lower the efficiency - meaning a larger portion of input power is converted into heat. Efficiency is therefore the most fundamental factor determining the power supply's lifespan.
Non-isolated designs generally offer higher efficiency than isolated ones, typically above 80%. However, the efficiency of isolated designs depends on how they are matched with the LED board.
Conclusion
In summary, the technical requirements for LED street lights cover multiple aspects - constant current accuracy, voltage and current design, power supply matching, series-parallel configuration, electrolytic capacitor setup, and power supply efficiency. Only by rigorously controlling every detail can a stable, durable, and energy-efficient LED street light be achieved. Luxsky Lighting is committed to high technical standards and strict quality control, delivering LED street lights with excellent constant current accuracy, long service life, and stable light output. If you're looking for a reliable LED street light supplier, choose Luxsky Lighting - let quality light your way.
