An LED replacement lamp (20) is described. An LED lighting assembly (40) comprising LED lighting elements is electrically connected to filament emulation circuits, connected to electrical contacts at each of two opposite ends (22a, 22b) of an elongated member. The filament emulation circuits (42) each comprise a first resistor circuit (46) and a second resistor circuit (48) connected to first and second electrical contacts (26a, 24a). The first and second resistor circuits (46, 48) are connected to the LED lighting assembly (40) at a common terminal (50). In order to provide an LED replacement lamp for safe operation even in cases of component failure, and if the replacement lamp (20) is used in incorrect wiring configurations, the first and second resistor circuits (46, 48) each comprise a series connection of at least two resistors, in such a way that in case of failure of one of the resistors, the total resistance of the filament emulation circuits (42) remains above a determined resistance value.

A system includes lighting devices coupled to output supply pins, a microcontroller circuit, and a driver circuit, which receives data therefrom, and switches coupled in series to the lighting devices. The driver circuit includes output supply pins and selectively propagates a supply voltage to the output supply pins to provide respective pulse-width modulated supply signals at the output supply pins. The driver circuit computes duty-cycle values of the pulse-width modulated supply signals as a function of the data received from the microcontroller circuit. The lighting devices include at least one subset coupled to the same output supply pin. The microcontroller individually controls the switches via respective control signals to individually adjust a brightness of the lighting devices in the at least one subset of lighting devices.

A solid state lighting system includes a number of light sources with multiple light colors that can be used to replace fluorescent lamps.

A lighting device is disclosed. The lighting device includes a first light emitting element having a first color temperature, a second light emitting element having a second color temperature, a communication interface, and a processor configured to, when a first user input for adjusting a brightness of the lighting device is received via the communication interface, adjust both brightness of the first light emitting element and the second light emitting element based on the first user input, when a second user input for adjusting a color temperature is received, obtain ratio information of the brightness of the first light emitting element to the brightness of the second light emitting element based on the second user input, and adjust both brightness of the first light emitting element and the second light emitting element based on the obtained ratio information.

A load control device for controlling power delivered from an alternating-current power source to an electrical load may comprise a controllably conductive device, a control circuit, and an overcurrent protection circuit that is configured to be disabled when the controllably conductive device is non-conductive. The control circuit may be configured to control the controllably conductive device to be non-conductive at the beginning of each half-cycle of the AC power source and to render the controllably conductive device conductive at a firing time during each half-cycle (e.g., using a forward phase-control dimming technique). The overcurrent protection circuit may be configured to render the controllably conductive device non-conductive in the event of an overcurrent condition in the controllably conductive device. The overcurrent protection circuit may be disabled when the controllably conductive device is non-conductive and enabled after the firing time when the controllably conductive device is rendered conductive during each half-cycle.

An LED tube lamp having an LED unit is disclosed. The LED tube lamp includes a control circuit that selectively determines whether to perform a first mode or a second mode of lighting operation according to a state of a property of an external driving signal and a switching circuit coupled to the control circuit and the LED unit. When the control circuit determines to perform the first mode of lighting operation, the control circuit controls the second circuit in a manner such that the switching circuit maintains its on state to allow continual current to flow through the LED unit, until the external driving signal is disconnected from the LED tube lamp, and when the control circuit determines to perform the second mode of lighting operation, the control circuit controls the switching circuit in a manner to regulate the continuity of current to flow through the LED unit by alternately turning on and off the switching circuit.

A LED driver comprises two output contacts (310, 311) and an additional contact (312) which enables detection of connection of the LED driver to a LED module (301). The LED driver has a normal current regulating mode and an open circuit protection voltage regulating mode. The LED driver is switched from the voltage regulating mode to the current regulating mode in response to the detection of connection of the LED module. This enables a LED module to be connected to the LED driver while it remains powered, in particular because the LED driver is placed in a voltage regulating mode prior to connection to the LED module.

A LED driver comprises two output contacts (310, 311) and an additional contact (312) which enables detection of connection of the LED driver to a LED module (301). The LED driver has a normal current regulating mode and an open circuit protection voltage regulating mode. The LED driver is switched from the voltage regulating mode to the current regulating mode in response to the detection of connection of the LED module. This enables a LED module to be connected to the LED driver while it remains powered, in particular because the LED driver is placed in a voltage regulating mode prior to connection to the LED module.

Light sources for replacing fluorescent lamps comprise light circuits with light emitting diodes, first and second terminals located at first and second ends of the light sources for exchanging first signals with high-frequency ballasts, and converter circuits for converting the first signals into second signals for feeding the light circuits. The converter circuits comprise reactive circuits for matching the light circuits and the high-frequency ballasts and provide safety to persons when installing the light sources. The light sources may further comprise protection circuits for protecting parts of the light sources against problems. The protection circuits may comprise monitor circuits for monitoring parameters of the light sources and for in response to monitoring results short-circuiting outputs of the converter circuits, and fuses. The reactive circuits may comprise protecting capacitors.

A light emitting diode (LED) tube lamp includes a lamp tube having four pins for receiving an external driving signal; a first rectifying circuit coupled to two of the four pins to rectify the external driving signal; a second rectifying circuit coupled to another two of the four pins to rectify the external driving signal; a filtering circuit coupled to the first and the second rectifying circuits to filter rectified signal; and an LED lighting module coupled to the filtering circuit to receive filtered signal to emit light. The first rectifying circuit further includes a terminal adapter circuit for providing four terminals correspondingly coupled to the four pins. With function of the terminal adapter circuit, the LED tub lamp is compatible with an AC driving mode and a ballast driving mode. The LED lighting module further includes a driving circuit having a controller and a converter circuit. The controller receives a current detection signal for controlling or stabilizing the driving signal output by the converter circuit to be above an objective current value. The controller is further coupled to the filtering circuit for setting the objective current value according to the voltage output by the filtering circuit.