An apparatus to drive a multi-channel light emitting diode (LED) array includes switching transistors connected to LED strings of the multi-channel LED array, error amplifiers connected to the switching transistors, each of the error amplifiers being configured to control current flowing through the LED string to have a target magnitude, and overheating protection circuits connected to the switching transistors, each of the overheating protection circuits being configured to regulate current flowing through a respective switching transistor to have a magnitude less than or equal to the target magnitude.

Disclosed is a rectifierless light string that uses bidirectional LEDs. Each LED is illuminated on both the positive and the negative portion of an AC signal so that the AC signal does not have to be rectified. In addition, LEDs are mounted on LED holder plugs, which are designed to allow the LEDs and bypass resistors to be automatically inserted in the LED holder plug. The LED holder plugs are inserted into a light string socket that contains a shunt switch that provides a conduction path when the LED holder plug is not firmly inserted in the light string socket. In this manner, conduction can occur in the light string when the LED holder plug is dislodged.

A load control device for controlling the amount of power delivered to an electrical load may include a rectifier circuit configured to receive a phase-control voltage and produce a rectified voltage. A power converter may be configured to receive the rectified voltage at an input and generate a bus voltage. An input capacitor may be coupled across the input of the power converter. The input capacitor may be adapted to charge when the magnitude of the phase control voltage is approximately zero volts. The power converter may be configured to operate in a boost mode, such that the magnitude of the bus voltage is greater than a peak magnitude of the input voltage. The power converter may be configured to operate in a buck mode to charge the input capacitor from the bus voltage when the magnitude of the phase-control voltage is approximately zero volts.

An electrical system can include first and second electrical loads. The electrical system can also include a first power supply coupled to the first electrical load, where the first electrical load receives first power from the first power supply at a first time. The electrical system can further include a second power supply coupled to the second electrical load, where the second electrical load receives second power from the second power supply at the first time. The electrical system can also include a first switch disposed between and coupled to the first electrical load and the second power supply. The first switch, when in an open position at the first time, can prevent the second power from being received by the first electrical load. The first switch, when in a closed position at a second time, can allow the second power to be received by the first electrical load.

A ballast circuit for a lighting system using an induction fluorescent lamp utilizes an AC-DC rectification circuit, a DC-DC boost power conversion circuit, a DC-AC half bridge inverter circuit, and a resonating circuit to ignite the lamp and maintain substantially constant power output of the lamp, while the DC-AC half bridge inverter circuit is further comprised of a gate isolation transformer connected in a half bridge inverter schematic which uses a ballast integrated circuit (IC) to drive a high side MOSFET and a low side MOSFET and the gate isolation transformer electrically isolates a gate signal to the high side MOSFET.

A portable solar power management system includes (i) a solar panel interface to one or more solar panels, (ii) an energy storage interface to one or more energy storage devices, (iii) a charging circuit which routes the electrical currents from the solar panels to the energy storage devices; (iv) a load interface to one or more load devices, the load devices being powered independently on primary and secondary load circuits; and (v) a controller for controlling the operations of solar panel interface, the energy storage interface, the charging circuit, and the load interface. In addition, a secondary load control circuit and a programmable controller may be provided which route the electrical currents from the energy storage devices to the load interface, wherein the programmable controller, based on the sensing signals, also activates and deactivates the secondary load circuit.

An LED tube lamp includes a glass tube, a plurality of LED light sources, two end caps respectively sleeving two end portions of the glass tube, a power supply in one of the end caps or separately in both of the end caps, and an LED light strip in the glass tube. The plurality of LED light sources is on the LED light strip. Each of the end caps comprises a plurality of openings formed thereon. The plurality of openings dissipating heat resulted from the power supply are divided into two sets. The two sets of the plurality of openings are symmetric to each other with respect to a virtual central axis of the end cap.

The disclosure is directed to an obstruction lighting and power line control system. The system includes at least one light source, at least one controller coupled to and configured to control the at least one light source, a power line cable providing power to the at least one light source, and a power supply coupled to the power line cable and configured to provide power to the at least one light source over the power line cable. The disclosure further includes a system controller configured to control the power supply to provide power over the power line cable to the at least one light source and the at least one controller that indicates at least one of the following: operating parameters and operating modes.

A light emitting diode system includes a light emitting diode lamp string, a signal voltage unit and a control unit. The light emitting diode lamp string includes a plurality of light emitting diode units. The control unit drives the signal voltage unit to adjust a voltage of the light emitting diode lamp string continuously and repeatedly so the voltage of the light emitting diode lamp string is a predetermined voltage, to form a light signal comprising a plurality of pulse waves to send the light signal to the light emitting diode lamp string. When each of the light emitting diode units receives the light signal, each of the light emitting diode units performs a conversion and a decoding for the light signal to obtain a lighting mode of the light signal, and then each of the light emitting diode units lights based on the lighting mode.

A system for providing power over Ethernet emergency lighting is disclosed. The system includes a rechargeable battery pack that is charged without interfering with data signals present on a power over Ethernet link that provides normal lighting. The system includes a power loss monitor for monitoring the presence of normal lighting power present on a power over Ethernet link without interference.