Abstract: The invention relates to a LED light source comprising: input terminals (K1, K2) for connection to a mains voltage supply source, a rectifier (RB) coupled to the input terminals for rectifying the mains supply voltage supplied by the mains supply voltage source and comprising rectifier output terminals, a DC-DC converter (CONV) for generating a DC current out of the rectified mains supply voltage, comprising converter input terminals connected to the rectifier output terminals and comprising a first converter output terminal (A) and a second converter output terminal (B), —a LED load (LL) with an anode coupled to the first converter output terminal via a current control element (D5) for blocking a current flowing from the anode of the LED load to the first converter output terminal, and with a cathode coupled to the second converter output terminal via a first controllable switch (M1) having a control electrode coupled to first control circuitry for rendering the controllable switch non-conductive in case the

Abstract: The invention relates to LED lighting system comprising a power supply circuit and one or more LED modules. The power supply circuit is equipped with input terminals (K1, K2) for connection to a supply voltage source and first and second output terminals (K3, K4), and a driver circuit (I, II) coupled between the input terminals and the first and second output terminals for generating a LED current. The driver circuit (I, II) comprises a driver control circuit (II) equipped with an input terminal (K7) for increasing or decreasing the LED current in dependency of a signal present at the input terminal of the driver control circuit.

Abstract: A lighting unit (100) includes light emitting diode (LED) modules (120, 300) and a lighting driver (110, 200) connected to the LED modules. Each LED module includes LEDs (323) and an identification current source (324) supplying an identification current to an identification current output node (180, 380). All of the identification current output nodes are connected together to supply a total identification current having a magnitude which changes in response to the number of LED modules that are connected to the lighting driver. The lighting driver includes: a controllable current source (220 & 250) to supply an LED driving current to the LEDs of the LED modules, and a controller (230) that responds to the total identification current to control the controllable current source to supply the LED driving current at a magnitude which changes in response to the number of LED modules that are connected to the lighting driver.

Abstract: The invention relates to a LED lighting system comprising a power supply circuit for supplying a LED current, equipped with input terminals (K1, K2) for connection to a supply voltage source and output terminals (K3, K4), modulation circuitry (MS, DC2), coupled between the output terminals, for alternately maintaining the voltage between the output terminals at a high level during a first time interval and a low level during a second time interval, a current sensor (R1, R2, S1) for sensing the current through the output terminals during the second time interval, and a driver circuit (DC1, DC2), coupled between the input terminals and the output terminals and coupled to the current sensor, for generating the LED current, out of a supply voltage supplied by the supply voltage source, wherein the LED current equals the current sensed by the current sensor multiplied by a predetermined constant multiplication factor and for supplying the LED current to the output terminals during each first time interval.

Abstract: Disclosed is a light source having a plurality of light elements and a control system for controlling the light elements. The control system includes a plurality of light element controllers, each connected to a respective light element, and arranged to obtain light element data; and a bus interface, which is connected to the light element controllers via a light source bus. The bus interface provides the light element controllers with a general command, and the light element controllers generate light element drive signals on basis of the general command and the light element data.

Abstract: A lighting unit (100) includes light emitting diode (LED) modules (120, 300) and a lighting driver (110, 200) connected to the LED modules. Each LED module includes LEDs (323) and an identification current source (324) supplying an identification current to an identification current output node(180, 380). All of the identification current output nodes are connected together to supply a total identification current having a magnitude which changes in response to the number of LED modules that are connected to the lighting driver. The lighting driver includes: a controllable current source (220 & 250) to supply an LED driving current to the LEDs of the LED modules, and a controller (230) that responds to the total identification current to control the controllable current source to supply the LED driving current at a magnitude which changes in response to the number of LED modules that are connected to the lighting driver.

Abstract: The invention relates to a LED light source comprising: input terminals (K1, K2) for connection to a mains voltage supply source, a rectifier (RB) coupled to the input terminals for rectifying the mains supply voltage supplied by the mains supply voltage source and comprising rectifier output terminals, a DC-DC converter (CONV) for generating a DC current out of the rectified mains supply voltage, comprising converter input terminals connected to the rectifier output terminals and comprising a first converter output terminal (A) and a second converter output terminal (B), —a LED load (LL) with an anode coupled to the first converter output terminal via a current control element (D5) for blocking a current flowing from the anode of the LED load to the first converter output terminal, and with a cathode coupled to the second converter output terminal via a first controllable switch (M1) having a control electrode coupled to first control circuitry for rendering the controllable switch non-conductive in case the

Abstract: The invention relates to a LED lighting system comprising a power supply circuit for supplying a LED current, equipped with input terminals (K1, K2) for connection to a supply voltage source and output terminals (K3, K4), modulation circuitry (MS, DC2), coupled between the output terminals, for alternately maintaining the voltage between the output terminals at a high level during a first time interval and a low level during a second time interval, a current sensor (R1, R2, S1) for sensing the current through the output terminals during the second time interval, and a driver circuit (DC1, DC2), coupled between the input terminals and the output terminals and coupled to the current sensor, for generating the LED current, out of a supply voltage supplied by the supply voltage source, wherein the LED current equals the current sensed by the current sensor multiplied by a predetermined constant multiplication factor and for supplying the LED current to the output terminals during each first time interval.

Abstract: The invention relates to LED lighting system comprising a power supply circuit and one or more LED modules. The power supply circuit is equipped with input terminals (K1, K2) for connection to a supply voltage source and first and second output terminals (K3, K4), and a driver circuit (I, II) coupled between the input terminals and the first and second output terminals for generating a LED current. The driver circuit (I, II) comprises a driver control circuit (II) equipped with an input terminal (K7) for increasing or decreasing the LED current in dependency of a signal present at the input terminal of the driver control circuit.

Abstract: A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

Abstract: A power supply circuit has an LLC converter stage for converting a DC voltage input into a DC voltage output, and at least one hysteretic converter stage. Each hysteretic converter stage has a DC voltage input coupled to the DC voltage output of the LLC converter stage, and a DC current output. The LLC converter stage lacks a feedback control, and is operated at its load independent point. A ripple on the DC voltage output of the LLC converter does not affect the output current of the hysteretic converter stage. The stable DC current output of the hysteretic converter stage is coupled to a load having one or more LED strings.

Abstract: Disclosed is a light source having a plurality of light elements and a control system for controlling the light elements. The control system includes a plurality of light element controllers, each connected to a respective light element, and arranged to obtain light element data; and a bus interface, which is connected to the light element controllers via a light source bus. The bus interface provides the light element controllers with a general command, and the light element controllers generate light element drive signals on basis of the general command and the light element data.

Abstract: Light source having a plurality of light elements (207) and a control system for controlling the light elements. The control system comprises a plurality of light element controllers (213), each connected to a respective light element (207), and arranged to obtain light element data; and a bus interface (203), which is connected to the light element controllers (213) via a light source bus (209). The bus interface (203) provides the light element controllers (213) with a general command, and the light element controllers generate light element drive signals on basis of the general command and the light element data.

Abstract: A lighting device (1) comprises a plurality of LEDs (11-14) producing light (21-24) of mutually different colors. The LEDs are driven in switching cycles (63) with a duty cycle controlled supply current of constant magnitude. In each switching cycle, each LED is first switched ON (61) and then switched OFF (62). In a measuring mode, during one switching cycle (63B), all ON phases of all LEDs are briefly interrupted, except for one LED (11), so that a light sensor (70) measures the light from this one LED. This measurement can be used to adapt the duty cycle of this one LED. In the next switching cycle (63C), the interruption of the ON phases is compensated by extending the ON phases of all LEDs except said one LED, the extension having a duration equal to the duration (?D) of the interruption.

Abstract: A system providing deep dimming of a solid state lighting (SSL) load includes a hysteretic down-converter, a shunt switch, a controller and a comparator. The down-converter controls average current value and amplitude of ripple of SSL current using amplitude modulation (AM) dimming control. The shunt switch controls magnitude of the SSL current using pulse width modulation (PWM) dimming control. The controller generates first and second PWM signals for controlling upper and lower current levels at which the down-converter operates based on the SSL current and voltage across the SSL load, and generates a third PWM signal for controlling the shunt switch based on a dimming level load set by a dimmer. The comparator circuit compares first and second analog signals corresponding to the first and second PWM signals with the SSL current, and drives the down-converter in response to the comparison. The SSL current is based on both the AM dimming control and the PWM dimming control.

Abstract: A lighting device (10) comprises a LED (4), a driver (3), and a controller (2) which regularly switches from a drive state to a measuring state and back. In the measuring state, the controller controls the driver such that the driver does not generate any LED current. The LED produces a measuring signal (Sm) indicating a measured light level. The controller processes the measuring signal received from the LED, and makes a decision on the desired light output of the LED. In the drive state, the controller controls the driver such that the average light output produced by the LED corresponds to the desired light output as determined in the measuring state. In a possible embodiment, the driver generates a nominal LED current INOM, and sets the duration (?1) of the drive state on the basis of the desired light output of the LED as determined in the measuring state.

Abstract: A dimmable LED driver circuit comprises a resonant DC-DC converter coupled to an output circuit. The converter comprises a half bridge or full bridge switching circuit coupled to a resonant circuit. An output of the resonant circuit is rectified and fed to the output circuit. The output circuit may comprise at least one LED series or shunt switch for switching an LED unit on and off. A control circuit controls the switches of the switching circuit at a variable switching frequency. The control circuit is also configured for controlling the switching circuit for amplitude modulating the converter and for pulse-width modulating the converter at a first pulse-width modulation frequency lower than the switching frequency. The control circuit is may further be configured for controlling the switching of the LED switch at a second pulse-width modulation frequency lower than the switching frequency.

Abstract: A power supply circuit has an LLC converter stage for converting a DC voltage input into a DC voltage output, and at least one hysteretic converter stage. Each hysteretic converter stage has a DC voltage input coupled to the DC voltage output of the LLC converter stage, and a DC current output. The LLC converter stage lacks a feedback control, and is operated at its load independent point. A ripple on the DC voltage output of the LLC converter does not affect the output current of the hysteretic converter stage. The stable DC current output of the hysteretic converter stage is coupled to a load having one or more LED strings.

Abstract: A method for dimming an illumination system (20) capable of emitting light (L) with a variable color is described. The illumination system (20) comprises three dimmable light sources (21, 22, 23) generating respective lights (L1, L2, L3) having respective, mutually different colors (C1, C2, C3). The method comprises the step of reducing the light intensities (I1, I2, I3) of the three dimmable light sources (21, 22, 23) while maintaining the color point until one of said light sources (21) reaches a lower dim limit (IMIN)—The method further comprises the step of maintaining the light intensity (I1) of said one light source (21) at its lower dim limit (IMIN) and reducing the light intensities (I2, I3) of the two other dimmable light sources (22, 23) in such a manner that the hue is maintained.

Abstract: A lamp driver circuit (400) comprises a feedback circuit for controlling stable operation of a discharge lamp (La), e.g. an inductively coupled discharge lamp such as a molecular radiation lamp, and for controlling a light output level of the discharge lamp (La). In particular, if the discharge lamp (La) is operated at a dimmed light output level, the light output is sensitive to changes in the lamp voltage (VLa), possibly resulting in flickering. In order to control stable lamp operation and prevent flickering, a high-sp feedback circuit is provided for controlling an operating frequency. In order to provide a relatively large dimming range for controlling the light output level, a low-speed feedback circuit is provided for controlling a DC supply voltage level (VDC).