Application features of the LDDS-H series from MEAN WELL

LDDS-H series LED drivers are popular power supplies for track lights and/or individual LEDs and modules, so it is important to understand the features of this series for the most efficient use. A detailed description of the LDDS-H drivers is provided here.

A special feature of LED lighting systems is the requirement to stabilize the output parameters of their power sources – voltage or current. Since the luminance of LEDs (individual semiconductor devices) directly depends on the level of current flowing, current stabilization is required to ensure a constant luminance. Power supplies that provide a fixed current level are commonly referred to as current-stabilized LED drivers (or Constant Current, CC).

The output current is the stabilized parameter in LED drivers, and its level does not depend on changes in the input voltage and/or load resistance, that is, the output voltage changes, which "adjusts" to the rated current level. However, the nominal output current level is the average current value, and pulsed LED drivers are characterized by the presence of ripples _out. The ripple level Δi _out is determined by the design features of the LED driver and the selected topology.

The shape of the LED driver output current and the ripple level Δi _out

Due to the small overall dimensions of the LDDS-H series driver and the fairly wide ranges of its operating modes, the price for these advantages is a fairly high ripple level of the order of 20% or higher. Therefore, if it is important to ensure a low level of pulsation, it is advisable to use other, more specialized LED power sources for the operating conditions.

The second feature of the LDDS-H series drivers is a very wide output power range from 2 to 45W, which can be set by the input voltage level for the rated current. For example, for LDDS-1000HW(B), at an input voltage level of 30V, the output power will be about 15W (rated output current of 1000mA). At the maximum input voltage level (56V), the output power will also be maximum – about 45W. Separately, it can be noted that due to the very high efficiency, its own power losses are minimal, and therefore additional cooling is not required even at maximum power.:

Output and input parameters of LDDS-H LED drivers

The third feature of the LDDS-H series drivers is the presence of a built–in dimmer (in the HWB modification), which allows you to change the output current level by setting the brightness of the connected LEDs. Dimming is performed using PWM (pulse width modulation) at a fixed frequency from 100 Hz to 1 kHz (the frequency is set for the model and there is no way to change it). This PWM control frequency is sufficient so that light pulsations are not detected by the human eye, but in some cases (for example, photo or video shooting) these pulsations may be noticeable.

The shape of the output current in the dimming mode

The average value of the output current Iout_dim (shown as a dotted line) is determined by the fill factor D (duty cycle) – the ratio of the duration of the tdim output current supply to the PWM period Tdim. Accordingly, the shorter the duration of the output current, the lower the average value of the output current and the lower the brightness level of the LED. The dimming parameters are fixed throughout the LDDS-H series, and do not depend on the input voltage level and/or load resistance.

Main technical characteristics and features of LDDS-H series DC/DC converters:

• Standard output current range: 250/300/350/500/700/1000 mA.
• DC/DC converter type: DC/DC step-down.
• Wide input voltage range: 12-56V (DC).
• Output voltage: 2-45V (DC), always lower than the input.
• High efficiency: up to 96%.
• Modifications: remote ON/off function (Power ON/OFF control); built-in 3-in-1 dimmer.
• Cooling due to natural ventilation.
• Full silicone filling of the case.

For more detailed technical specifications, see the Specifications for LDDS series DC/DC converters, and for questions related to the selection and use of MEAN WELL products, please contact the email address Meanwell@chipdip.ru .