A driving device that includes a temperature monitoring circuit, a headroom voltage monitoring circuit, a power supply voltage monitoring circuit, and a control unit. The temperature monitoring circuit detects a temperature of a drive circuit that drives a light emitting element in a test light emission period of the light emitting element. The headroom voltage monitoring circuit detects a headroom voltage of the drive circuit in the test light emission period. The power supply voltage monitoring circuit detects a power supply voltage supplied to the light emitting element in the test light emission period. The control unit adjusts the power supply voltage in the test light emission period according to an input/output potential difference of the light emitting element varying depending on the temperature of drive circuit so as to obtain a headroom voltage necessary and sufficient for causing a prescribed drive current to flow through the light emitting element.

An ultraviolet irradiation device includes a light-emitting element, a temperature control element, and a control circuit. The light-emitting element is configured to emit an ultraviolet light. The temperature control element is configured to control a temperature of the light-emitting element. The control circuit is configured to control the temperature control element based on a voltage of the light-emitting element so as to control a peak wavelength of the ultraviolet light.

An ultraviolet irradiation device includes a light-emitting element, a temperature control element, and a control circuit. The light-emitting element is configured to emit an ultraviolet light. The temperature control element is configured to control a temperature of the light-emitting element. The control circuit is configured to control the temperature control element based on a voltage of the light-emitting element so as to control a peak wavelength of the ultraviolet light.

An object detection system compensates for variations in transmission characteristics within an object passageway caused by, for example, dust or dirt. An object detection device includes a plurality of electromagnetic radiation emitters and detectors arranged in rows on opposite sides of a passageway. First lenses focus radiation from the emitters into a semi-columnated beams of radiation that together create a plane of semi-columnated electromagnetic radiation that spans substantially across a width of the passageway. Second lenses focus the received electromagnetic radiation onto corresponding ones of the plurality of radiation detectors. A controller receives a radiation intensity signal from the detectors, determines that its value is outside of a predetermined range, and adjusts an amount of electrical power supplied to the plurality of radiation emitters so that the value of the radiation intensity signal changes to become within the predetermined range.

An object detection system compensates for variations in transmission characteristics within an object passageway caused by, for example, dust or dirt. An object detection device includes a plurality of electromagnetic radiation emitters and detectors arranged in rows on opposite sides of a passageway. First lenses focus radiation from the emitters into a semi-columnated beams of radiation that together create a plane of semi-columnated electromagnetic radiation that spans substantially across a width of the passageway. Second lenses focus the received electromagnetic radiation onto corresponding ones of the plurality of radiation detectors. A controller receives a radiation intensity signal from the detectors, determines that its value is outside of a predetermined range, and adjusts an amount of electrical power supplied to the plurality of radiation emitters so that the value of the radiation intensity signal changes to become within the predetermined range.

Disclosed are a temperature sampling device and method, a temperature protection device and method, and a lighting system. The temperature sampling device comprises: a temperature measurement unit and a signal processing unit, the temperature measurement unit having a measurement end and configured to change its own resistance under the influence of an ambient temperature change of a circuit to be protected, and the signal processing unit being coupled to the measurement end and configured to limit a measurement signal in the temperature measurement unit that is influenced by a resistance change so as to output a temperature sampling signal corresponding to the resistance change, wherein the temperature sampling signal is generated under the condition that the measurement signal is limited. The temperature sampling device and method, the temperature protection device and method, and the lighting system have simple structure and low costs. In addition, the temperature sampling device can be directly coupled to pins of switch power sources in the existing LED lighting systems, and therefore has high universality.

Disclosed are a temperature sampling device and method, a temperature protection device and method, and a lighting system. The temperature sampling device comprises: a temperature measurement unit and a signal processing unit, the temperature measurement unit having a measurement end and configured to change its own resistance under the influence of an ambient temperature change of a circuit to be protected, and the signal processing unit being coupled to the measurement end and configured to limit a measurement signal in the temperature measurement unit that is influenced by a resistance change so as to output a temperature sampling signal corresponding to the resistance change, wherein the temperature sampling signal is generated under the condition that the measurement signal is limited. The temperature sampling device and method, the temperature protection device and method, and the lighting system have simple structure and low costs. In addition, the temperature sampling device can be directly coupled to pins of switch power sources in the existing LED lighting systems, and therefore has high universality.

A charge voltage calibration system comprises a power supply, a light string, a driver, and a calibration circuit. The driver comprises a capacitor, a switch, and a sense resistor. The switch, sense resistor, and light string are coupled in series to form a discharge path coupled in parallel with the capacitor. The calibration circuit comprises a controller, a DAC, a comparator, a memory device. The controller is configured to control the DAC to provide a reference voltage to the comparator, cause the power converter to supply a first charge voltage to the driver, cause the switch to transition from an off state to an on state to discharge stored energy in the capacitor through the discharge path, and store a value of the first charge voltage in the memory device in response to detection of voltage generated across the sense resistor being greater than or equal to the reference voltage.

A charge voltage calibration system comprises a power supply, a light string, a driver, and a calibration circuit. The driver comprises a capacitor, a switch, and a sense resistor. The switch, sense resistor, and light string are coupled in series to form a discharge path coupled in parallel with the capacitor. The calibration circuit comprises a controller, a DAC, a comparator, a memory device. The controller is configured to control the DAC to provide a reference voltage to the comparator, cause the power converter to supply a first charge voltage to the driver, cause the switch to transition from an off state to an on state to discharge stored energy in the capacitor through the discharge path, and store a value of the first charge voltage in the memory device in response to detection of voltage generated across the sense resistor being greater than or equal to the reference voltage.

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.