The disclosure disclose a control circuit and a lighting device, relates to a technical field of illumination. In the power-on process of the control circuit, the voltage input to the driving input terminal of the constant current driving module rises slowly, resulting in the current overshoot phenomenon of the light source load. In the control circuit disclosed by the present disclosure, because the output current of the first regulation output terminal is positively correlated with the output voltage of the voltage limiting terminal, and the output current of the second regulation output terminal is negatively correlated with the output voltage of the voltage limiting terminal, during the power-on process of the control circuit, that is, during the voltage at the voltage limiting terminal is changed from zero to the first threshold value, the current input to the driving input terminal can be relatively constant.

A two-stage driver supplies current to an LED load. A first stage of the driver generates a bulk voltage. A second stage has a flyback transformer with a primary winding and a secondary winding. The second stage generates an output voltage to cause LED load current. The primary winding is turned on and off by a gating signal. Control logic within the second stage is responsive to initially turning on the driver to perform a startup short circuit test of the output circuit by applying a gating signal with a short on-time and a low switching frequency. If the output circuit is not shorted, the control logic increases the on-time and the switching frequency to detect if an output current is excessive. If the output current is not excessive, the control logic adjusts the on-time and the frequency to provide sufficient current to illuminate the LED load.

A circuit for driving a light-emitting diode (LED) load and a direct current to direct current (DC-DC) converter includes a first sampling sub-circuit, a driving circuit. The first sampling sub-circuit is configured to generate a current signal representing a load current of the LED load. The driving circuit is configured to receive a brightness adjustment signal and a frequency adjustment signal; generate a first control signal, based on the current signal and the brightness adjustment signal, for controlling an output current of the DC-DC converter; and generate a second control signal, based on the frequency adjustment signal, for controlling a switching frequency of the LED load.

LED related lighting methods and apparatus are described. Various features relate to water tight light fixtures. Some of the fixtures are spotlights while other fixture are intended for in ground use. The light fixtures in at least some embodiments include power control features. In spotlight embodiments beam angle and power or light output can be controlled without opening the light assembly or compromising the water tight seals which also protect against dirt. In ground embodiments support tilt angle setting which allow a user to set the light fixture to one or more tilt angles. Beam angle can also be changed in some embodiments as well as power control. Beam angle, power control and tilt angle adjustments are supported in some embodiments but need not be supported in all embodiments with some embodiments using one or more of the described features but not all features.

The present disclosure describes a pulsed ultraviolet (PUV) device and method of operating the PUV device for enhanced UV disinfection. The method may comprise generating a plurality of charging commands during an operation cycle of the PUV device. In an aspect, generating the plurality of charging commands may comprise generating a plurality of variable voltage amplitudes for charging a capacitor provided in the PUV device. The plurality of variable voltage amplitudes comprises at least one voltage amplitude greater than a cut off voltage amplitude. The method may further comprise generating a plurality of discharging commands corresponding to the plurality of charging commands for discharging the capacitor to generate IN pulses across the germicidal lamp.

A lighting relay panel may include lower-cost features or components related to improved safety and reliability. In some cases, the relay panel includes a power supply capable of protecting the panel from high-voltage and high-current transients. A microcontroller may determine a power interruption based on a zero-cross signal received from the power supply, and may also configure latching relays during the interruption. In some implementations, the relay panel includes a relay sense circuit that is capable of receiving actuation signals from multiple relays connected to different phases of a power signal, and the microcontroller may synchronize or repeat the actuations based on a signal from the relay sense circuit. The microcontroller may generate relay addresses based on the relay positions within the relay panel. In some cases, the relay panel may include isolation circuits that are capable of providing an isolated control signal having an improved voltage range.

A lighting relay panel may include lower-cost features or components related to improved safety and reliability. In some cases, the relay panel includes a power supply capable of protecting the panel from high-voltage and high-current transients. A microcontroller may determine a power interruption based on a zero-cross signal received from the power supply, and may also configure latching relays during the interruption. In some implementations, the relay panel includes a relay sense circuit that is capable of receiving actuation signals from multiple relays connected to different phases of a power signal, and the microcontroller may synchronize or repeat the actuations based on a signal from the relay sense circuit. The microcontroller may generate relay addresses based on the relay positions within the relay panel. In some cases, the relay panel may include isolation circuits that are capable of providing an isolated control signal having an improved voltage range.

A method is provided for driving a half bridge circuit that includes a first transistor and a second transistor that are switched in a complementary manner. The method includes generating an off-current during a plurality of turn-off switching events to control a gate voltage of the second transistor; measuring a transistor parameter of the second transistor during a first turn-off switching event during which the second transistor is transitioned to an off state, wherein the transistor parameter is indicative of an oscillation at the first transistor during a corresponding turn-on switching event during which the first transistor is transitioned to an on state; and activating a portion of the off-current for the second turn-off switching event, including regulating an interval length of the second portion for the second turn-off switching event based on the measured transistor parameter measured during the first turn-off switching event.

A light-emitting element driving semiconductor integrated circuit that constitutes at least a portion of a light-emitting element driving device configured to drive a plurality of light-emitting elements connected in series includes: a controller configured to have a first mode in which switching control is performed on a transistor connected in series to the plurality of light-emitting elements and a second mode in which linear control is performed on the transistor; and a first detector configured to detect that a current flowing through a sense resistor connected in series to the plurality of light-emitting elements and the transistor reaches a threshold value, wherein the controller switches from the switching control to the linear control based on an output of the first detector.

A lighting apparatus includes a string of light emitting diode (LED) sets coupled in series where each set includes at least one LED. A current diversion circuit is coupled to the string and is configured to operate responsive to a bias state transition of one of the LED sets to direct current away from another one of the LED sets. A current limiting circuit is coupled in series with the string and is configured to conduct current responsive to a forward biasing of all of the LED sets. The current limiting circuit includes only passive electrical component(s).