Philips Lighting Holding B.v.

Signify Holding B.v.

Liwen Zhou

Qi Zhang

Shiguang Sun

Lin Wang

Shujin Zhuang

Lyle Liu

Liang Zhou

Chenhao Kou

An LED driver, comprising: an inductive switch mode converter having an inductive component (), an LED output () for an LED load and a main converter switch () for controlling a current flowing through the inductive component; a sensor () for generating a sensor signal indicative of the output current or voltage provided to the LED output; a feedback element () which provides a feedback path for feeding back the sensor signal for control of the main converter switch (); and a processing circuit () for processing the sensor signal which has been fed back, wherein the processing circuit is adapted to generate an output when there is no sensor signal so as to limit the current flowing through the main converter switch when no sensor signal is present.

LED driver and an LED driving method

Proposed is a device management apparatus and method for use in a device management network including a remote device management system. The device management apparatus comprises a communication interface () adapted to receive device management commands of differing nature from the remote device management system and to transmit a feedback signal to said remote device management system if requested by said device management commands, wherein the differing nature of a device management command comprises a differing level of power required to process the device management command, wherein the differing level of power required to process the device management command further relates to whether or not the device management command requires the communication interface () to transmit the feedback signal. The device management apparatus comprises a power supply () adapted to supply power to the communication interface () of the device management apparatus and further adapted to operate in a plurality of differing predefined operating modes. The device management apparatus further comprises a control unit () adapted to control the power supply to operate in one of the plurality of operating modes based on the nature of a received device management command, wherein the control unit () is adapted to: set the power supply () operating under respective predefined switching frequency or duty cycle in a first power mode or in a second power mode of the plurality of differing predefined operating modes.

Device management

A DC-DC converter has a pulse width control circuit producing a sequence of pulses, with an on time, an off time and a switching frequency. The on time as well as the switching frequency are both varied in dependence on a dimming setting.

LED driver and control method

Growing community of inventors

Eindhoven, Netherlands

Liwen Zhou