We know that all LEDs must be powered by a constant current source, but many street lamp manufacturers are currently looking for suitable constant current modules when the LED modules have been designed. As everyone knows, this design method is problematic, at least making this design not optimal. It is possible to redesign the LED module.
I often receive a phone call from the customer. How much power can your constant current drive module bring? This kind of problem is actually unanswerable. Because the power that a constant current module can carry is related to many factors. From the constant current module itself, it is mainly related to the heat dissipation requirements and heat dissipation conditions, and of course to the current drive capability of the driver chip. However, even if these have been determined, for example, the SLM2842 constant current module has been selected, then his driving ability seems to be completely certain! actually not! Although its ultimate drive capability is known, for example, its maximum switching current, its maximum input current, its maximum input voltage and maximum output voltage. However, the driving power of a constant current module is related to its heat dissipation capability, and its main efficiency is related to its working efficiency. And its work efficiency is related to many external factors, especially the user's use. Therefore, when designing or selecting LED modules, we must consider the requirements and characteristics of constant current sources.
one. LED connection architecture
There are some considerations related to constant current modules and other requirements when designing and selecting LED modules.
1. The number of LEDs in series should be less than 10, because there is a safety requirement as an LED luminaire. According to the European Union IEC 61347-2-13 (5/2006) standard, for LED modules with DC or AC power supply, the voltage in the LED luminaire must not exceed the maximum safety extra low voltage (SELV), that is, its working output voltage ≤ 25 Vrms (35.3 Vdc), so the total number of LEDs in series must not exceed 10.
2. As street lamps, LED modules are usually used for repair and replacement. Each module is usually designed in a rectangular shape, and a constant current module is also designed. It is recommended that the power of each module be less than 30W. Thus, 3-4 LED modules are used for street lamps of about 100 W, and 5-6 LED modules are used for 150W LED street lamps. For high power, you can use 7-8 modules.
3. In each LED module, a 1W LED is usually used, and the connection mode is serial-parallel. If the LED has a protection diode, then it can be stringed first, and if there is no protection diode, then it must be followed by a string, so as not to damage one string.
4. To use a few strings, it is necessary to further understand the performance and characteristics of the constant current module.
two. Constant current module performance and characteristics
The ordinary regulated power supply is that the output voltage does not change when the load changes. The constant current module is a type of power supply that maintains a constant output current when the input voltage changes. Before using it, you must understand its various characteristics.
1. Current setting: Generally, the output current of the constant current module can be adjusted according to the user's requirements in a large range. Simply change the output current setting resistor.
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