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All colleagues unite and focus their efforts to write a new chapter of developmentWhat factors should you consider when selecting an LED driver?
所属分类： Industry News
发布时间：2020-05-28
Based on the characteristics of grid electricity consumption, the requirements for LED performance, and relevant LED products, when selecting…
LED driver power supply The following points should be taken into consideration:
General Principles
a. Based on the current and voltage characteristics of LEDs, constant-current driving is generally preferred. It prevents current fluctuations caused by variations in the LED’s forward voltage, while a stable current ensures consistent brightness.
b. In addition, LED luminous flux is inversely proportional to temperature; therefore, during operation, it is advisable to minimize power‑supply heat generation and to design an effective thermal management system, thereby reducing the ambient operating temperature of the LED.
c. To ensure the overall lifespan of LED products, the LED junction temperature must be kept within a specified range, which requires proper control of the operating ambient temperature.
1. High reliability
LED products primarily consist of LED chips, power supplies, heat‑dissipating housings, and control circuits. The quality of the LED power supply directly affects the overall performance of the product. This is especially true for LED streetlights, which are installed at high altitudes, making maintenance difficult and costly.
2. High efficiency
LEDs are energy‑efficient products, and their driver power supplies must also meet energy‑saving requirements. This is especially true for power supplies integrated within the luminaire, as LED luminous efficacy declines with rising junction temperature. A highly efficient power supply dissipates less power, generating less heat inside the fixture and thereby reducing its temperature rise—both of which help to slow down LED lumen depreciation.
3. Constant-current drive method
To match the LED’s current–voltage characteristics, the LED power supply must employ constant-current driving.
4. Surge Protection
LEDs have relatively poor shock resistance, so robust protection in this regard is essential. This is especially true for outdoor‑mounted products, where power‑grid load switching and lightning strikes can both impose severe surges on the power supply. Consequently, the input stage of an LED driver should incorporate surge‑suppression circuitry to prevent instantaneous switching transients from damaging the LEDs.
5. Temperature protection function
In addition to standard protection features, it is advisable to incorporate negative temperature feedback for the LED chip in constant-current output mode to prevent excessive junction temperatures.
6. LED Power Supply Lifespan
To extend the lifespan of LED driver power supplies, improvements must be made on multiple fronts: using higher‑life‑rating capacitors, enhancing power efficiency, ensuring effective thermal management, and optimizing the luminaire’s heat‑dissipation design. LED power supplies are switching-mode power supplies, and their quality and reliability hinge on circuit design, manufacturing processes, and component quality. Electrolytic capacitors are an indispensable component in high‑power switching power supplies. Moreover, the operational life of a switching power supply is largely determined by the lifespan of its electrolytic capacitors, which in turn depends on both the capacitor’s intrinsic longevity and its operating temperature; the service life of electrolytic capacitors varies significantly across different temperature ranges.
7. Work Environment
Due to varying environmental conditions across different locations, it is essential to carefully consider the operating environment of LED luminaires, including factors such as temperature, humidity, and installation location.
Considering the power supply’s operating characteristics, without a soft-start circuit, the output will exhibit a voltage spike at the moment of power-up. To better protect the LED, a soft-start circuit is therefore necessary. This factor is precisely one of the key determinants of the driver’s stability.