Abstract: A lamp driver has a transformer, a primary side circuit and a secondary side circuit. The primary side circuit comprises a half bridge circuit and a sensor circuit for measuring a conduction time or switching frequency of one of the transistors of the half bridge circuit. An estimate is provided of the output voltage from the measured conduction time.

Abstract: A retrofit Light Emitting Diode, LED, lighting device for connection to a ballast, wherein said ballast is arranged to be connected to a mains voltage and arranged to provide for a ballast current, wherein said LED lighting device is arranged to detect a dip in said mains voltage using a zero current detector.

Abstract: A retrofit Light Emitting Diode, LED, lighting device for connection to a ballast, wherein said ballast is arranged to be connected to a mains voltage and arranged to provide for a ballast current, wherein said LED lighting device is arranged to detect a dip in said mains voltage using a zero current detector.

Abstract: A retrofit lamp is to be used with a ballast. A shunt switch is provided in parallel with an output load and is adapted to shunt input terminals of the lamp using pulse width control so as to tune the current through the lighting element. This current control is used to enable compatibility with different ballasts and to provide dimming control. A detection circuit is used to detect an abnormal drive condition of the retrofit lamp and the pulse width control of the shunt switch can then be overridden by holding the shunt switch at a stable state for a certain duration. This prevents overload conditions and avoids DC signals in the event of component failures.

Abstract: A retrofit lamp is to be used with a ballast. A shunt switch is provided in parallel with an output load and is adapted to shunt input terminals of the lamp using pulse width control so as to tune the current through the lighting element. This current control is used to enable compatibility with different ballasts and to provide dimming control. A detection circuit is used to detect an abnormal drive condition of the retrofit lamp and the pulse width control of the shunt switch can then be overridden by holding the shunt switch at a stable state for a certain duration. This prevents overload conditions and avoids DC signals in the event of component failures.

Abstract: The invention describes an isolated driver (2) comprising a converter module (21) realized to provide voltage and current output to a load (3); a feedback arrangement (22) realized to monitor voltage and/or current during operation of the driver (2); and a converter controller (1) for providing converter control signals (CI, CF, VCON) to the converter module (21), and wherein the converter controller (1) comprises a single optocoupler (10) connected by input terminals to the feedback arrangement (22); and a switching circuit arrangement (11) connected to output terminals of the optocoupler (10), comprising a number of semiconductor switches (Q20, Q25, Q30, . . . , Q34) arranged to generate a converter control signal (CI, CF, VCON) for placing the converter module (21) of the driver (2) into a low-output mode (MLO) when a voltage across the optocoupler output terminals indicates a fault condition.

Abstract: The invention describes an isolated driver (2) comprising a converter module (21) realized to provide voltage and current output to a load (3); a feedback arrangement (22) realized to monitor voltage and/or current during operation of the driver (2); and a converter controller (1) for providing converter control signals (CI, CF, VCON) to the converter module (21), and wherein the converter controller (1) comprises a single optocoupler (10) connected by input terminals to the feedback arrangement (22); and a switching circuit arrangement (11) connected to output terminals of the optocoupler (10), comprising a number of semiconductor switches (Q20, Q23, Q30, . . . , Q34) arranged to generate a converter control signal (CI, CF, VCON) for placing the converter module (21) of the driver (2) into a low-output mode (MLO) when a voltage across the optocoupler output terminals indicates a fault condition.

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 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: 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: 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: A lighting driver includes a shunt switch circuit configured to detect when an input of the lighting driver is connected to mains power without a ballast, and in response thereto to disable the lighting driver, and further configured to detect a type of ballast connected to the input of the lighting driver when the input of the lighting driver is connected to the ballast, and to regulate a bus voltage of the shunt switch circuit according to the detected type of ballast; and a switching mode power supply configured to receive the bus voltage of the shunt switch circuit and in response thereto to supply a lamp current to drive one or more light emitting diodes.

Abstract: A circuit arrangement is disclosed with a regulating circuit which is particularly used for regulating a resonant converter having a plurality of outputs. The arrangement includes a protective circuit that can be constructed with the least possible circuitry and cost. The regulating circuit is used for generating a pulse-width modulated regulation signal (20) in dependence on measuring signals (Va, Vb) present on inputs of the regulating circuit (20). The arrangement further includes a comparator circuit (212) for comparing the duty cycle (?) of the regulation signal (20) with a predefinable maximum duty cycle value (?max) and minimum duty cycle value (?min), in which in case of a duty cycle (?) situated outside the range between the maximum duty cycle value (?max) and the minimum duty cycle value (?min) the circuit arrangement delivers control information that corresponds to this exceeding of the range.

Abstract: The invention relates to a circuit arrangement with a regulating circuit which is particularly used for regulating a resonant converter having a plurality of outputs.

Abstract: DC/DC conversion circuit (1), includes a transformer (2) having a primary winding (3), a secondary winding (4), and an auxiliary winding (5); a switching transistor (T), including a series circuit with the primary winding (3) between first and second direct current input terminals (6; 7); a start circuit (R1, C1) connected to a control electrode of the switching transistor (T) for switching the switching transistor (T) on by powering the direct current input terminals (6; 7); a control transistor connected to the control electrode of the switching transistor (T) for switching off the switching transistor (T) in dependence on a current flowing through the series circuit during operation.

Abstract: DC/DC conversion circuit (1), comprising a transformer (2) having a primary winding (3), a secondary winding (4), and an auxiliary winding (5); a switching transistor (T), comprising a series circuit with the primary winding (3) between first and second direct current input terminals (6; 7); a start circuit (R1, C1) connected to a control electrode of the switching transistor (T) for switching the switching transistor (T) on by powering the direct current input terminals (6; 7); a control transistor connected to the control electrode of the switching transistor (T) for switching off the switching transistor (T) in dependence on a current flowing through the series circuit during operation.