Drivers (1-7) comprise respective switching circuits (1, 2) for guiding respective current signals during respective time-intervals for the sequential driving of light emitting circuits (91, 92). The respective time-intervals are defined by the fact that amplitudes of a mains signal are in respective ranges during the respective time-intervals. More specifically, there is a bypass switching circuit (5) for guiding a bypass current signal which bypasses all light emitting circuit (91, 92) during an initial time-interval. An adaptation circuit (6, 7) adapts amplitudes of the respective current signals during the respective time-intervals, to reduce a total harmonic distortion. Said adapting may comprise an adaptation in response to information derived from the amplitude of the mains signal, and may comprise shaping the amplitudes of the current signals in response to information derived from the amplitude of the mains signal. Preferably, the shaped amplitudes of the respective current signals will be substantially identical to shapes of the amplitude of the mains signal in the respective ranges. The adaptation circuit (6, 7) may comprise a current source (6) and a definition circuit (7).

Flexible light engines capable of being cut, and methods thereof, are provided. A cuttable flexible light engine includes a flexible strip and strings of solid state light sources coupled in parallel. A voltage balancer establishes a desired current flow through the strings of solid state light sources when the flexible strip is cut to a desired length, and may be part of a connector placed where the strip is cut. The strings may be provided in a first set of strings coupled in parallel between a first conductive path and an intermediate conductive path and a second set of strings coupled in parallel between the intermediated conductive path and a second conductive path. A cuttable flexible light engine may also include test points positioned within the strings.

A light source control system includes a plurality of light sources, and a plurality of light source control devices. The light source control devices include a plurality of main light source control devices that transmits command signals to the other light source control devices. Each main light source control device includes a collision determination circuit that determines whether data of the command signal transmitted through a bus has collided with other data, and a restoration circuit that executes a restoration operation in the case of a collision. The collision determination circuit includes an edge detection circuit that detects change timing of a signal representing the data of the command signal, an area setting circuit that sets a collision determination area in accordance with the detected change timing detected, and a collision detection circuit that detects the presence or absence of a collision in the set collision determination area.

A lighting fixture includes a solid-state lighting source, such as an LED light source. A control module of the lighting fixture uses temperature sensing circuitry to determine a relative ambient temperature. When the ambient temperature is above a defined ambient temperature threshold, a drive signal is provided to the solid-state light source at a target drive level that corresponds to a normal light output level. When the ambient temperature is below the ambient temperature threshold, the drive signal is provided to the solid-state light source at a reduced drive level, which is lower than the target drive level.

An LED tube lamp is disclosed. The LED tube lamp includes a lamp tube, a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal, a rectifying circuit coupled to the first external connection terminal and the second external connection terminal and configured to rectify the external driving signal to produce a rectified signal, a filtering circuit coupled to the rectifying circuit and configured to filter the rectified signal to produce a filtered signal, an LED module coupled to the filtering circuit and configured to receive the filtered signal for emitting light; and a conduction-delaying circuit coupled to the rectifying circuit and comprising a conduction-delaying device, wherein the conduction-delaying circuit is configured such that when the external driving signal is initially input to the LED tube lamp, the conduction-delaying device is in an open-circuit state, and then the conduction-delaying device will enter a conducting state when voltage across the conduction-delaying device exceeds the conduction-delaying device's trigger voltage value, wherein the conducting state of the conduction-delaying device causes the LED module to conduct current for emitting light.

A protection circuit and an illumination driving circuit are described herein. The protection circuit comprises a detection circuit, detecting a current flowing through a first switch to obtain a current detection signal and determining whether there is leakage at an input terminal according to the current detection signal; a control circuit, controlling the first switch to switch on intermittently, detecting the current flowing through the first switch by the detection circuit during a switch-on period of the first switch, and keeping the load at a disconnection state if the detection circuit determines there is leakage; and the first switch, connected to the input terminal, and a control terminal of the first switch being connected to the control circuit, and the first switch being controlled by the control circuit to be switched on intermittently. The present invention has the protection function and enhances safety during load removing and installation processes.

The present disclosure relates to a starting device for a CDM lamp, comprising: a full-bridge inverter, which at least provides an output as a starting power source to initiate the CDM lamp to work normally; a driving circuit for driving the full-bridge inverter; a single-chip microcomputer, which is connected to the driving circuit; an ignition determining module, one end of which is connected to the full-bridge inverter to sense whether the output of the full-bridge inverter has powered on the CDM lamp, so as to determine whether ignition of the CDM lamp succeeds and then output a result of the determining to the single-chip microcomputer via the other end. The present disclosure provides a novel starting device for a CDM lamp, which facilitates determining whether starting of the CDM lamp succeeds and also facilitates enhancement of successful rate of starting the CDM lamp subsequently.

An LED tube lamp is disclosed. An installation detection circuit is configured in the LED tube lamp configured to receive an external driving signal. The installation detection circuit is configured to detect during one or more pulse signals whether the LED tube lamp is properly installed on a lamp socket, based on detecting a signal generated from the external driving signal. The installation detection circuit includes a switch circuit coupled to the pulse generating circuit, wherein the one or more pulse signals control turning on and off of the switch circuit. The installation detection circuit is further configured to: when it is detected during one or more pulse signals that the LED tube lamp is not properly installed on the lamp socket, control the switch circuit to remain in an off state to cause a power loop of the LED tube lamp to be open; and when it is detected during one or more pulse signals that the LED tube lamp is properly installed on the lamp socket, control the switch circuit to remain in a conducting state to cause the power loop of the LED tube lamp to maintain a conducting state.

A lighting device includes: a first lighting control circuit; a second lighting control circuit which controls the first lighting control circuit; a first control power supply which supplies a first voltage to the first lighting control circuit; a second control power supply to which the first voltage is supplied and which supplies a second voltage to the second lighting control circuit; and a reset circuit which (i) when the reset circuit detects that the first voltage decreases to a first threshold or lower, causes the second control power supply to stop supply of the second voltage, and (ii) when the reset circuit detects that the first voltage increases to a second threshold or higher and that the second voltage is higher than a third threshold, causes the second control power supply to start supply of the second voltage after the second voltage decreases to the third threshold or lower.

An LED control circuit controls a switching operation of a switch by hysteretic control. The LED control circuit includes a controller integrated circuit (IC) that senses a current sense voltage from a current sense resistor that is on a low-side of the switch. The LED control circuit senses the current sense voltage during on-time of the switch to determine when to turn off the switch. During off-time of the switch, the controller IC determines when to turn on the switch by comparing a sawtooth voltage to a turn-on threshold that is generated from the on-time of the switch.