MEAN WELL DC/DC LED Driver Applications

Buck, Boost and Buck-Boost

The AC power source of AC-DC LED drivers is directly linked to the mains, but the DC power source of DC-DC LED drivers can come from either an AC-to-DC power supply or a DC input, such as a centralized power supply bus or a battery.

Historically, when high-power LED luminaires were in their infancy of development, the LED chip production method and materials might have a significant impact on the LED forward voltage difference. As depicted in Figure 1 (below), each loop of the LED light string will be equipped with a linear constant current source to ensure the current range of each channel for a longer LED luminaire life. In the majority of instances, a constant current source is supplied by a linear IC or a DC-DC LED driver. Figure 2 (below) depicts that, as a result of the optimization of the LED process, the lowering of the LED forward voltage difference, and the demand for high-efficiency lamps, high-power lamps are predominantly "directly driven." DC-DC LED drivers are becoming more widespread in applications such as mobile illumination, solar streetlights, centralized power supply, and others.

LED Driver IC Schematic Figure 1: Constant current or constant voltage LED Driver with linear Driver IC

LED Driver Schematic Figure 2: LEDs drivern directly by the constant current LED driver

Based on their structure, DC-DC LED drivers can be divided into buck, boost, and buck-boost categories.

Classification Models Features
Buck LDD-L/H(DA)
The driving voltage of the LED light string is lower than the DC supply voltage.
It is generally used in centralized power supply lighting applications such as
48V power supply magnetic commercial track lights, 24V pool lighting or
landscape applications.
Boost LDH-25/45(DA)/65 The driving voltage of the LED light string is higher than the DC supply voltage.
It is generally used in single-string high voltage or large-wattage lamps, such as
solar street lighting that can be powered by 12V/24V batteries, then powered
by a boosted DC/DC power supply. The boosted voltage
is used for the LED light string to enlarge the range and wattage of the
LED driver voltage.
Buck-Boost LDB-L Ideal for low-wattage applications. Regardless of wheter the driving voltage
of the LED light string is lower or higher than the DC supply voltage.

Buck Application

As environmental awareness and demand for energy savings and carbon reduction increase, the prevalence of electric vehicles and green energy grows. High-voltage DC centralized power distribution is anticipated to be the future trend in power distribution. As depicted in Figure 3, the high-voltage DC power supply busbar is built into the room. The output voltage of MEAN WELL power supply includes the UHP-1500-HV and RST-7K5-HV series, as well as 380VDC. It can also be used with the step-down DC-DC LED driver, series NHDD-40, to power the room's illumination.

LED Driver House Diagram Figure 3: DC House Lighting Concept

Boost Application

Solar energy, which is portrayed as a limitless and eco-friendly new energy source, is one of the solutions to the energy crisis. Numerous low- and medium-powered streetlights are currently powered by solar energy. A boost type DC-DC LED driver can be used to increase the number of LEDs in series while decrease the number of LEDs in parallel when the power consumption for solar streetlights is high. In comparison to a buck-type DC-DC LED driver, the current is reduced, and hence, power loss is minimized. The overall energy efficiency has greatly boosted.

As seen in Figure 4, when sufficient sunlight is present, the solar panel charges the battery via the MPPT controller. Typically, a low-voltage battery, such as a 12VDC or 24V DC battery, is used for safety reasons because it has a more consistent charging performance. During the night, the boost DC-DC LED driver, LDH-25/45(DA)/65, within the lamp may enhance the battery voltage by 12V or 24V to power solar LED streetlights or mobile LED lighting fixtures with higher wattages. As demonstrated in Figure 5, increased LED driving power can also be applied to automotive or ship batteries as a DC-powered source.

LED Driver Street Lights Figure 4: Street Lamp Solar System Structure

LED Driver Auto Lights Figure 5: Interior Car Light Application

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MEAN WELL is the industry leader in the production of conventional AC/DC power supplies, LED drivers, DC/DC converters, and DC/AC inverters. As an industry pioneer, their products are renowned for their superior quality, dependability, and efficiency. Product copy and images provided by MEAN WELL.