Philips Lighting Holding B.v.

Signify Holding B.v.

Junhu Liu

Xianhui Zhang

Jie Fu

Zhi Quan Chen

Marco Haverlag

Shu Xu

Peter Alexander Duine

Chun Yang

Xiao Sun

Shan Shan Wang

Herman Johannes Gertrudis Gielen

Biwen Xu

Ken K Li

Ace Li

Gang K Wang

Gang G Wang

The invention describes a coded light modulation arrangement (), adapted to be connected between a driver () and a LED (), which coded light modulation arrangement () comprises input terminals () adapted to connect to the driver () and to receive a drive current (I), an energy storage arrangement comprising a number of energy storage devices (EE); a data input interface () realized to receive a data stream (D), said data stream (D) comprises a sequence of binary symbols comprising a logic high and a logic low; a switch arrangement comprising a number of switches (SS) arranged to connect the energy storage devices (EE) of the energy storage arrangement and to modulate the drive current such that, in a charging switch configuration corresponding to the logic low, a negative modulation current (I) is diverted from a drive current (I) of the LED () to the energy storage arrangement; and, in a discharging switch configuration corresponding to the logic high, a positive modulation current (I) is drawn from the energy storage arrangement and added to the drive current (I) of the LED (); and output terminals () adapted to connect to the LED () and to provide the modulated drive current directly to the LED () to emit the low and high radiant flux level as coded light (L) to be received by a photosensor of a coded light receiver device. The invention further describes a method of performing coded light modulation for light emitted by a LED (); a luminaire; and a coded light communication arrangement ().

Coded light modulation arangement

An LED driver uses a switch mode power supply either to provide a regulated LED current (in a first mode) that connects directly to the LED arrangement or a regulated LED voltage (in a second mode) to an LED output terminal. An auxiliary power supply is either based on an auxiliary secondary side (i.e. an auxiliary secondary side winding) when in the first mode, or it is based on the regulated LED voltage when in the second mode. The LED driver further comprises an input adapted to receive a standby command for the driver, wherein the main controlling unit is adapted to control the driver in the second mode when receiving the standby command for the driver. In this way, the driver has a single shared stage which can operated in a regulated current (i.e. constant current) mode to drive the LED arrangement directly or a regulated voltage (i.e. constant voltage) mode. It can adaptively change between modes to improve the standby power efficiency. When the load is turned on (e.g. a first mode), the driver may function in constant current mode, and when the load is turned off (e.g. a second, standby mode), the driver works in constant voltage mode with the output voltage stepped down so that not sufficient to turn on the LED arrangement to be driven by the driver but enough to provide auxiliary power via the auxiliary power supply, in order to improve the auxiliary power efficiency.

LED driver and driving method

The invention provides a power converter comprising: an input for receiving input power with a variable nominal mains level, wherein said variable nominal mains level falls within at least 90V to 240V; a main power switch (Q) driven by the input power, and a control circuit (Q, Q) for controlling a control current of the main power switch (Q), wherein the control circuit in (Q, Q) is adapted to sense the level of the input power and draw current from a control terminal of the power switch (Q) according to the level, and said control circuit is adapted to operate in linear region and increase the drawn current along with the increase of the level throughout the variable nominal mains level of the input power, wherein the control circuit comprises: a Darlington bridge with a first transistor (Q) and a second transistor (Q), the first transistor (Q) with a base terminal connected to a circuit position indicative of the voltage amplitude of the input power, the second transistor (Q) with a base terminal connected to an emitter terminal of the first transistor (Q) and a collector terminal connected to the control terminal of the main power switch (Q) and a collector terminal of the first transistor (Q); and a resistor network (R, R) coupled to the emitter of the second transistor (Q) for regulating the amplification of the second transistor (Q) and keep the second transistor (Q) working at linear region throughout the variable nominal mains level of the input power.

Power converter and an LED lighting circuit comprising the same

The invention relates to a drive unit for a lighting element and an operating method for such drive unit and to a lighting element including such drive unit. By selectively providing power to a control unit of the drive unit using different voltages at different stages of the overall drive unit, there is an additional degree of freedom which may be used for improving power efficiency, in particular for reducing standby power consumption, while still meeting specific space and cost constraints.

Drive unit for a lighting element and operating method therefor

A lighting controller and method has light sources which are activated for a respective lighting duration in a repeating non-overlapping sequence. The end of the lighting duration for one light source is detected for triggering the switching on of the next light source in the sequence. This provides non-overlapping control of the light sources and provides an efficient and easy to implement the required controller.

Method of controlling a lighting arrangement, a lighting controller and a lighting system

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Shanghai, China

Junhu Liu