MEAN WELL LDH-25 Series: DC-DC Step-Up Constant Current LED Driver

Product Description

The MEAN WELL LDH-25 series is a 25W DC/DC LED driver featuring constant current output. It operates from a 9.5~32VDC input and offers models with rated currents ranging from 250mA to 700mA. With high efficiency up to 95.5%, the fully-potted silicone enhances heat dissipation, making this series suitable for solar LED street lighting. The LDH-25 is equipped with various dimming function options, providing optimal design flexibility for DC source LED lighting systems.

Product Styles

Available in two styles:

• Pin mounted style: Compact design for direct PCB mounting.
• Lead wire style: Features flexible lead wires for easier connection.

Features

• Wide DC input voltage operation: 9.5~32V
• DC/DC step-up converter
• Constant current output: 250mA to 700mA
• Wide output LED forward voltage up to 84V DC
• High efficiency up to 95.5%
• 2-in-1 dimming (0-10V, PWM)
• Protections: Short circuit / Over voltage
• Cooling by free air convection
• Fully encapsulated
• 3 years warranty

Applications

• DC battery source lighting
• Portable lighting
• LED solar street lighting
• LED greenhouse lighting
• LED Low-bay lighting

GTIN Code

For GTIN code information, please visit: MEAN WELL GTIN Search

Model Encoding

The model encoding follows the pattern: LDH-25-[Output Current] [Style].

• LDH-25: Series name
• Output Current: 250, 350, 500, or 700mA
• Style: Blank for Pin mounted style, 'W' for Lead wire style.
• Rated wattage: Typically 25.2W.

Specifications

Mechanical Specifications & Pin Configuration

LDH (Pin Style)

Dimensions: 52.4mm (Length) x 27.2mm (Width) x 24mm (Height). Tolerances: ±1mm.

Pin Configuration:

• Pin 1: Vin+ (DC Supply)
• Pin 2: Vin- (DC Supply, do not connect to Vout-)
• Pin 3: Dim+ (2-in-1 dimming)
• Pin 4: Dim- (2-in-1 dimming)
• Pin 5: Vout- (LED connection)
• Pin 6: Vout+ (LED+ connection)

LDH (Lead Wire Style)

Dimensions: 52.4mm (Length) x 27.2mm (Width) x 24mm (Height). Tolerances: ±1mm.

Pin Configuration:

• Pin 1 (Red): Vin+ (DC Supply)
• Pin 2 (Black): Vin- (DC Supply, do not connect to Vout-)
• Pin 3 (Blue): Dim+ (2-in-1 dimming)
• Pin 4 (White): Dim- (2-in-1 dimming)
• Pin 5 (Black): Vout- (LED connection)
• Pin 6 (Red): Vout+ (LED+ connection)

Derating Curve

This graph illustrates the maximum load percentage versus ambient temperature (Ta) for different input voltage ranges (12-18V and 18-32V). For 12-18V input, the derating starts around 50°C. For 18-32V input, derating begins around 60°C, with both curves reaching 25% load at 70°C.

Static Characteristics

This graph shows the relationship between input voltage and output load percentage. The output load is maintained at 100% across a wide input voltage range, typically from 12V up to 32V, indicating stable operation.

Standard Application: 2-in-1 Dimming Function

The output constant current level can be adjusted using one of two methodologies between the DIM+ and DIM- terminals: 0-10VDC or 10V PWM signal (frequency range 1KHz ~ 3KHz). Direct connection to LEDs is suggested; use with additional drivers is not recommended.

Applying Additive 0-10VDC

A diagram shows the DIM+ and DIM- terminals connected to an "Additive Voltage" source. A note states: "DO NOT connect 'DIM-' to Vo-". The corresponding graph shows output current percentage versus dimming input voltage. At 0V, output current is approximately 10%; at 10V, it is 100%.

Applying Additive 10V PWM Signal

A diagram shows the DIM+ and DIM- terminals connected to an "Additive PWM signal" source. A note states: "DO NOT connect 'DIM-' to Vo-". The corresponding graph shows output current percentage versus the duty cycle of the PWM signal. At 0% duty cycle, output current is approximately 10%; at 100% duty cycle, it is 100%.

Notes on Dimming:

• Minimum dimming level is approximately 8%. Output current is not defined for levels between 0% and 8%.
• When dimming input is 0Vdc or 0% duty cycle PWM, the output voltage is approximately equal to the input voltage. To achieve complete darkness, luminaires should be turned off externally.

Efficiency vs. Load Graphs

Multiple graphs display the efficiency (%) of different LDH-25 models (250mA, 350mA, 500mA, 700mA) across various input voltages (12VDC and 24VDC) and numbers of LEDs. Generally, efficiency is high, often exceeding 90-95%, and remains relatively stable across the tested load ranges.

• LDH-25-250: Efficiency shown for 12VDC input (Vf=3.05V) and 24VDC input (Vf=3.05V).
• LDH-25-350: Efficiency shown for 12VDC input (Vf=3.14V) and 24VDC input (Vf=3.14V).
• LDH-25-500: Efficiency shown for 12VDC input (Vf=3.18V) and 24VDC input (Vf=3.18V).
• LDH-25-700: Efficiency shown for 12VDC input (Vf=3.29V) and 24VDC input (Vf=3.29V).

Application Notes

1. The positive and negative input terminals must be connected correctly. Applying negative voltage can damage the power supply.
2. Due to the high input current, pay attention to the voltage drop in the wiring to ensure proper power supply operation.
3. At dim off, the LDH output voltage will drop to the same level as the input voltage. To achieve complete darkness, luminaires should be turned off externally.

Application Notes of EMC

EMC Compliance:

• If the LDH-25 is powered by a battery, it complies with BS EN/EN55015 without additional input filters or capacitors.
• If the LDH-25 is powered by a DC Bus, additional EMC filter parts are required to meet BS EN/EN55015. The recommended circuit is shown in Figure 1.

Recommended EMC Filter Circuit (Figure 1)

The circuit includes a DC Bus input (positive and negative), connected through an electrolytic capacitor (C1: 100uF/35V) and a Common Mode Choke (LF1: 11.5mH, with specific winding and ferrite details). This filtered input then connects to the DC/DC converter's VIN+ and VIN-, with the output going to the LED Load via Vo+ and Vo-.