A lighting device circuit comprising: a reference LED string, a mirror LED string coupled in parallel to the reference LED string, an operational amplifier based current mirror circuit coupled to the reference LED string and to the mirror LED string, and a window comparator circuit that includes only a single input that is coupled to a fault sense node. The fault sense node directly connects to a drain node of a transistor within the operational amplifier based current mirror and a LED within the mirror LED string.

An airfield runway lamp controller is described herein. One airfield runway lamp controller includes a current sense transformer configured to detect a failure of a light source of an airfield runway lamp, and an alternating current (AC) switch configured to shunt the light source of the airfield runway lamp upon the current sense transformer detecting a failure of the light source.

Disclosed is a backlight test circuit including N circuit blocks. Each circuit block includes M mini-LED circuits, and each mini-LED circuit includes L mini-LEDs and a switching circuit. The L mini-LEDs are connected in parallel or in serial as a mini-LED set. The switching circuit controls the turning on and the turning off of the mini-LED set according to a control signal. N, M and M are positive integers. During a backlight test, in each circuit block, at least one of the mini-LED sets is turned on. By using this backlight test circuit, the abnormal mini-LED circuit can be found. Thus, a producer can only execute a rework process for the abnormal mini-LED circuit without extra cost.

Devices, methods, and systems for alternating current circuits for airfield lighting are described herein. One system includes a circuit comprising an isolation transformer, a protection hardware circuit coupled to the isolation transformer, wherein the protection hardware prevents a voltage between an electrical contact of the circuit and a ground contact from meeting or exceeding a threshold voltage, and a load coupled to the protection hardware circuit to receive electrical energy from the isolation transformer.

Apparatus, methods and systems for providing power to light-emitting diode (LED) light sources are provided. The apparatus may include a plurality of power output channels. Each of the power output channels may provide a current to a plurality of LED modules. Each of the LED modules may correspond to one of the power output channels. The apparatus may include a protection circuit. The protection circuit may receive a conditioned voltage. The protection circuit may use the conditioned voltage to feed to the power output channels an output current that, in total, has a power no greater than a predetermined power limit. The apparatus may include a voltage conditioning circuit. The voltage condition circuit may receive line voltage. the voltage condition circuit may condition the line voltage. The voltage conditioning circuit may provide the conditioned voltage to the protection circuit.

Apparatus, methods and systems for providing power to light-emitting diode (LED) light sources are provided. The apparatus may include a plurality of power output channels. Each of the power output channels may provide a current to a plurality of LED modules. Each of the LED modules may correspond to one of the power output channels. The apparatus may include a protection circuit. The protection circuit may receive a conditioned voltage. The protection circuit may use the conditioned voltage to feed to the power output channels an output current that, in total, has a power no greater than a predetermined power limit. The apparatus may include a voltage conditioning circuit. The voltage condition circuit may receive line voltage. the voltage condition circuit may condition the line voltage. The voltage conditioning circuit may provide the conditioned voltage to the protection circuit.

An LED backlight (15) having a plurality of LED groups (19) each including a plurality of LEDs (17) connected in series is tested. The LED groups (19a to 19c) are driven with a constant current respectively, and operating voltages (Vf1 to Vf3) of the LED groups (19a to 19c) are measured respectively. The LED backlight (15) is determined as normal when all of differences between the operating voltages (Vf1 to Vf3) are less than a reference value, and is determined as abnormal otherwise. With this, an open circuit failure and a short circuit failure of the LED (17) can be detected. A leakage failure of the LED (17) may be detected by switching an amount of a drive current used for driving with the constant current, to a minute current. Thus, the LED backlight is tested certainly and easily.

An LED driving apparatus group in which first and second LED groups are connected in series is provided. The apparatus includes a voltage input unit that receives an input voltage from a vehicle power device and a current controller that generates a current with a predetermined level by adjusting the received input voltage and provides the current to an input terminal of the first LED group. A first feedback path feeds back a voltage applied to a first node, which is connected to an output terminal of the first LED group, to an input terminal of the current controller. A first switching unit is disposed on the first feedback path and is switched on or off based on a control signal. A second switching unit is disposed between an output terminal of the second LED group and ground and is switched on or off based on the control signal.

A lighting system includes a plurality of light fixtures. Each light fixture includes a sensor for performing a test on the light fixture an generating test data. The light fixtures also include a hardware processor and a radio communication module. The radio communication module can communicate the test data to a mobile computing device or to a node. A diagnostic software application can receive the test data, identify a malfunctioning component, and order a replacement component.

Programmable drivers (or power supplies) for solid state light sources are disclosed, on which output regulation is improved to expand the dimming range to 1% and reduce and/or remove flicker. Additional fault conditions are set up to avoid latching, and thus provide for a controllable restart feature. Such drivers include an isolated half bridge resonant converter with an improved control approach designed to regulate very low current though primary side in a feed-forward loop. Such drivers include both digital and analog loops that improve the performance in steady state and/or during transients, particularly for a lighting load, in comparison to a single full digital control.