A radiation monitor for a lighting device, and operating methods and systems therefor are provided. In one example, a radiation monitor may include a first sensor receiving radiation output directly from a light-emitting element of the lighting device and radiation output from external sources; and a second sensor receiving the radiation output from the external sources without receiving the radiation output directly from the light-emitting element of the lighting device. The radiation monitor may determine an intensity of the radiation output directly from the light-emitting element based on a difference in the output signals from the first sensor and the second sensor.

A device includes a plurality of first LEDs, a plurality of second LEDs, at least one controllable current source that is configured to generate at least one bias current for driving the plurality of first LEDs and the plurality of second LEDs, and a plurality of measurement circuits, each of which is configured to measure a current-voltage (I-V) performance characteristic of at least one of the plurality of first LEDs. A property of a first bias current of the at least one bias current is determined as a function of at least two measurements of the I-V performance characteristic of the at least one of the plurality of first LEDs, and the at least two measurements of the I-V performance characteristic are acquired while the first bias current is applied to the at least one of the plurality of first LEDs and the plurality of second LEDs.

A Light Emitting Diode (LED) light includes a bridge rectifier configured to be powered by an alternating current power source and to produce a rectified output. Control circuitry couples to the bridge rectifier and is configured to produce a shunt signal when the rectified output is less than a threshold voltage. A series connected Light Emitting Diode (LED) string includes a first group of LEDs and a second group of LEDs. A switch couples to a first side of the second group of LEDs and is controlled by the shunt signal to deactivate the second group of LEDs. The control circuitry may include a ratio metric series resistor string configured to sense a proportion of the rectified output and an inverter configured to generate the shunt signal based on the proportion of the rectified output.

A Light Emitting Diode (LED) light includes a bridge rectifier configured to be powered by an alternating current power source and to produce a rectified output. Control circuitry couples to the bridge rectifier and is configured to produce a shunt signal when the rectified output is less than a threshold voltage. A series connected Light Emitting Diode (LED) string includes a first group of LEDs and a second group of LEDs. A switch couples to a first side of the second group of LEDs and is controlled by the shunt signal to deactivate the second group of LEDs. The control circuitry may include a ratio metric series resistor string configured to sense a proportion of the rectified output and an inverter configured to generate the shunt signal based on the proportion of the rectified output.

An LED driver circuit includes a rectifying module, a control unit, and at least two LED light strings. The control unit includes a voltage input detection terminal and a switch assembly. The voltage input detection terminal is configured to detect the waveform of the voltage input. The switch assembly changes the way of connection between the LED light strings according to the waveform of the voltage input.

A driver is configured to provide an output voltage and an output current to a load according to an input voltage. The driver includes a power converter, first and second detecting devices and a controller. The power converter is configured to receive and convert the input voltage to the output voltage and the output current. The first detecting device is configured to detect the input voltage to generate a first signal. The second detecting device is configured to detect the output voltage to generate a second signal, and detect the output current to generate a third signal. The controller is configured to perform a calculation to the second signal and the third signal according to one of lookup tables corresponding to the first signal to generate a power value. An operation method of a driver and a light source system are also disclosed herein.

A driver is configured to provide an output voltage and an output current to a load according to an input voltage. The driver includes a power converter, first and second detecting devices and a controller. The power converter is configured to receive and convert the input voltage to the output voltage and the output current. The first detecting device is configured to detect the input voltage to generate a first signal. The second detecting device is configured to detect the output voltage to generate a second signal, and detect the output current to generate a third signal. The controller is configured to perform a calculation to the second signal and the third signal according to one of lookup tables corresponding to the first signal to generate a power value. An operation method of a driver and a light source system are also disclosed herein.

An LED component according to the present invention comprising an array of LED chips mounted on a submount with the LED chips capable of emitting light in response to an electrical signal. The array can comprise LED chips emitting at two colors of light wherein the LED component emits light comprising the combination of the two colors of light. A single lens is included over the array of LED chips. The LED chip array can emit light of greater than 800 lumens with a drive current of less than 150 milli-Amps. The LED chip component can also operate at temperatures less than 3000 degrees K. In one embodiment, the LED array is in a substantially circular pattern on the submount.

A light-emitting diode (LED) tube lamp with overcurrent and/or overvoltage protection capabilities includes a lamp tube, a first rectifying circuit, a filtering circuit, an LED lighting module, and a protection circuit. The lamp tube has pins for receiving an external driving signal. The first rectifying circuit is for rectifying the external driving signal to produce a rectified signal. The filtering circuit is for filtering the rectified signal to produce a filtered signal. The LED lighting module includes an LED module, wherein the LED lighting module is configured to receive the filtered signal to produce a driving signal, and the LED module is for receiving the driving signal for emitting light. The protection circuit is configured to determine whether to enter a protection state, wherein upon entering the protection state, the protection circuit works to limit or restrain the level of the filtered signal.

Disclosed is a waterproof LED light string that provides outdoor lighting in a simple and reliable manner. Waterproof bulb assemblies are used with replaceable LED light sources. The bulb assemblies are easily suspended from a rope or wire, screwed to a support, or magnetically supported from a ferrous metal support. Duplicate circuitry in the LED light source allows the LED light source to be connected in either direction.