Analog interface – the easiest way to control brightness of a luminaire
Analog interfaces are used in lighting industry only for dimming. It is the most used dimming system for retail (e.g. spot lights in shops). Drawback is that it is not possible to switch off luminaire via analog dimming.
There are two basic analog interfaces:
• TE/LE – trailing/leading edge (thyristor regulation) – only one luminaire can be dimmed.
• 0-10 V, 1-10 V dimming – supports more than one controlled luminaire (Figure 4.5.1).
Figure 4.5.1: 1-10V dimming.
Digital interface – sophisticated communication with luminaire
Digital interface offers possibility to connect more LED drivers via digital interface, and control them independently. It also supports reading the status of each luminaire. Digital interface supports dimming, presence sensor, remote control, tunable white, scenic light schemes, etc.
Digital interfaces used in lighting industry:
• DALI-Digital Addressable Lighting Interface – most used (Figure 4.5.2)
• Others/read more
Figure 4.5.2: DALI interface.
If we duplicate some electronic parts inside the driver, we can connect and control two types of LEDs with different CCT – cool white and warm white (Figure 4.5.3). This allows for “tuning” CCT of light emitted by a luminaire and use it in various well-being applications.
Figure 4.5.3: Tunable white.
Based on actual temperature of LEDs (Figure 4.5.4), driving current can be decreased in order to avoid overheating of LEDs in case of excessive ambient temperature. Lifetime of LED light source can be easily maintained by this way.
Figure 4.5.4: Thermal feedback.
LED driver can easily have implemented remote control function for wireless control of luminaire (Figure 4.5.5).
Figure 4.5.5: Remote control.
LED driver with emergency feature continuously monitor permanent power line (Figure 4.5.6) and in case of black out, driver starts to bias light source from battery pack. Emergency units with batteries are commonly used which can supply luminaire in emergency mode for 1 or 3 hours. It is one of the most important features required by law for all public installations.
Figure 4.5.6: Emergency unit.