An LED specification system is provided having at least one LED light output device. The LED light output device has an LED light source, a first exchangeable face panel selectable from a plurality of potential exchangeable face panels, and a housing for locating the exchangeable face panel relative to the LED light source and for orienting the LED light source such that light from the LED light source passes through the first exchangeable face panel. The LED specification system further includes a user interface for selecting at least one preferred output characteristic for light from the LED light output device. The preferred output characteristic is defined by a metric value. The LED specification system further includes a transformation module for defining an LED specification value based at least partially on the defined metric value and a characteristic of the LED light source.

Novel electrically-isolated high-voltage sensors are provided which have low power dissipation. The sensors are formed of a circuit comprising first and second portions separated by an electrical isolation boundary with the first portion used for high-voltage, and the second portion for low-voltage. While they are decoupled electrically, they are coupled both optically and magnetically. The first portion comprises an LED which generates an optical signal corresponding to a high-voltage signal across the electrical-isolation boundary. The second portion comprises a photodiode which receives the optical signal emitted from the LED and outputs a corresponding low-voltage electrical signal. A temperature-compensating LED biasing sub-circuit may span both portions and include a temperature sensor, a coupled inductor magnetically coupling the electrical isolation boundary, and a rectifier and filter, to provide a bias to the LED which biases the LED to operate in a substantially-linear manner irrespective of the ambient temperature.

Novel electrically-isolated high-voltage sensors are provided which have low power dissipation. The sensors are formed of a circuit comprising first and second portions separated by an electrical isolation boundary with the first portion used for high-voltage, and the second portion for low-voltage. While they are decoupled electrically, they are coupled both optically and magnetically. The first portion comprises an LED which generates an optical signal corresponding to a high-voltage signal across the electrical-isolation boundary. The second portion comprises a photodiode which receives the optical signal emitted from the LED and outputs a corresponding low-voltage electrical signal. A temperature-compensating LED biasing sub-circuit may span both portions and include a temperature sensor, a coupled inductor magnetically coupling the electrical isolation boundary, and a rectifier and filter, to provide a bias to the LED which biases the LED to operate in a substantially-linear manner irrespective of the ambient temperature.

A current driving circuit configured to drive a light-emitting device is provided. The current driving circuit includes a first current generating circuit, a second current generating circuit and a driver circuit. The first current generating circuit is configured to generate a reference current. The second current generating circuit includes at least one variable resistor, and may generate a compensation current according to the at least one variable resistor. The at least one variable resistor is selected from at least one of a positive TCR resistor and a negative TCR resistor. The driver circuit is coupled to the first current generating circuit and the second current generating circuit, and configured to receive the reference current and the compensation current to serve as a driving current. The driver circuit outputs the driving current to drive the light-emitting device.

The present application provides an LED control system, including an LED driver chip, a thermistor independent of the LED driver chip, and a matching resistor of the thermistor, wherein different thermistors correspond to different matching resistors; the LED driver chip and the matching resistor are configured to generate corresponding LED control targets according to different thermistors; wherein the upper and lower limits of the control targets are preset by the LED driver chip regardless of the thermistor; and the slope of the change of control target over the change of temperature is fitted with the slope of the change of thermistor resistance over the change of temperature, and the upper and lower limits of the control target remains the same for different choices of thermistors. The present application also provides a corresponding LED control method.

The present application provides an LED control system, including an LED driver chip, a thermistor independent of the LED driver chip, and a matching resistor of the thermistor, wherein different thermistors correspond to different matching resistors; the LED driver chip and the matching resistor are configured to generate corresponding LED control targets according to different thermistors; wherein the upper and lower limits of the control targets are preset by the LED driver chip regardless of the thermistor; and the slope of the change of control target over the change of temperature is fitted with the slope of the change of thermistor resistance over the change of temperature, and the upper and lower limits of the control target remains the same for different choices of thermistors. The present application also provides a corresponding LED control method.

A discrete component linear circuit of a line is provided, including a switch S1, a fuse F1, a varistor MOV1, a rectifier DB1, a triode Q1 to a triode Q6, and a resistor R1 to a resistor R6, wherein an input end of the switch S1 is connected to an input end L of a power supply for input, and an output end of the switch S1 is connected to an input end of the fuse F1. When an input voltage increases, a current increases, and resistance values of a thermistor T1, a thermistor T2 and a thermistor T3 increase due to temperature rise. The resistance increases synchronously when the voltage increases, so that the current is maintained in a relatively stable interval. Therefore, the voltage bearing capacity when an LED lamp works is increased, and more LED lamps may be used in parallel.

An LED driving circuit and an LED lamp are provided. The driving circuit comprises a power input unit coupled to an input voltage; a voltage conversion unit coupled to the power input unit and converting the input voltage into a conversion voltage; a power output unit coupled to the LED light source; a first thermistor unit connected between the power input unit and the voltage conversion unit; a second thermistor unit connected between the voltage conversion unit and the power output unit, where the second thermistor unit and the conversion voltage generates a driving current passing through the LED light source; where the resistance of the first thermistor unit is positively correlated to its sensed temperature, and the resistance of the second thermistor unit is positively correlated to its sensed temperature to stabilize the driving current.

An LED driving circuit and an LED lamp are provided. The driving circuit comprises a power input unit coupled to an input voltage; a voltage conversion unit coupled to the power input unit and converting the input voltage into a conversion voltage; a power output unit coupled to the LED light source; a first thermistor unit connected between the power input unit and the voltage conversion unit; a second thermistor unit connected between the voltage conversion unit and the power output unit, where the second thermistor unit and the conversion voltage generates a driving current passing through the LED light source; where the resistance of the first thermistor unit is positively correlated to its sensed temperature, and the resistance of the second thermistor unit is positively correlated to its sensed temperature to stabilize the driving current.

An illuminator includes: a light emitter including a light-emitting diode; a temperature sensor configured to detect a current temperature of the light emitter; and an illumination controller configured to adjust a drive voltage being supplied to the light emitter in accordance with the current temperature. The illumination controller includes a reference temperature storage in which a reference temperature is stored in advance and is configured to adjust the drive voltage by detecting the current temperature from the temperature sensor on a constant time cycle and comparing the current temperature with the reference temperature.