Abstract: In order to reduce energy loss of a tapped linear driver, it is proposed an LED lighting circuit, comprising an input (Vbus, GND) adapted to receive an input voltage, a plurality of LED segments (LED1, LED2, LED3, LED) connected in series and to the input, a buffer component (C9) connected to an anode and a cathode of a series string of at least two of the plurality of LED segments with respective switches, a current source circuit (B1) in series connection with a parallel connection of the buffer component (C9) and the at least two LED segments, across the input; further comprising a further buffer component (C5) across the current source circuit (B1), wherein said buffer component (C9) and the further buffer component (C5) is in series connection.

Abstract: A LED lighting circuit has a plurality of LED segments connected in series. A switching arrangement is used to selectively bypass at least one LED segment to implement a tapped linear driver approach. Degrading of a component in the LED lighting circuit is detected, so that a first TLD current modulation scheme is implemented when no such degrading is detected whereas a second current modulation scheme, different from the first current modulation scheme, is implemented to compensate for said degrading. Said degrading is leading to an increase in a turning on voltage of one LED segment, and compared to said first current modulation scheme, said second current modulation scheme has a higher voltage threshold at which said LED segment is switched. In this way, protection may be provided for circuit components and the light output may be maintained at the desired level in the event of component degrading, such as LED chip failure or contact resistance changes.

Abstract: In order to reduce energy loss of a tapped linear driver, it is proposed an LED lighting circuit, comprising an input (Vbus, GND) adapted to receive an input voltage, a plurality of LED segments (LED1, LED2, LED3, LED) connected in series and to the input, a buffer component (C9) connected to an anode and a cathode of a series string of at least two of the plurality of LED segments with respective switches, a current source circuit (B1) in series connection with a parallel connection of the buffer component and the at least two LED segments, across the input; further comprising a further buffer component (C5) across the current source circuit (B1), wherein said buffer component (C9) and the further buffer component (C5) is in series connection.

Abstract: A LED lighting circuit has a plurality of LED segments connected in series. A switching arrangement is used to selectively bypass at least one LED segment to implement a tapped linear driver approach. Degrading of a component in the LED lighting circuit is detected, so that a first TLD current modulation scheme is implemented when no such degrading is detected whereas a second current modulation scheme, different from the first current modulation scheme, is implemented to compensate for said degrading. Said degrading is leading to an increase in a turning on voltage of one LED segment, and compared to said first current modulation scheme, said second current modulation scheme has a higher voltage threshold at which said LED segment is switched. In this way, protection may be provided for circuit components and the light output may be maintained at the desired level in the event of component degrading, such as LED chip failure or contact resistance changes.

Abstract: A lighting driver is for receiving an alternating current power supply from a fluorescent lighting ballast. A shunt device is provided for selectively shunting the power supply to implement dimming control. A detector is provided for generating a detection signal and for providing the detection signal to the control circuit to operate the shunt device. The detector has a detection circuit for analyzing a voltage at the driver input and generating 5 the detection signal accordingly, when the voltage is detected. In addition, for situations where the voltage detection does not correctly generate the detection signal, a correction circuit generates the detection signal for a time delay from the end of operating the shunt device. This prevents control stability problems at low dimming levels.

Abstract: There is proposed an interface circuit for connecting an electronic ballast to a lighting arrangement, in which control of a coupling configuration of the interface circuit is dependent upon a frequency of the electronic ballast. In particular, a coupling configuration of the interface circuit is controlled by a control arrangement based on the ballast frequency.

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 lighting driver is for receiving an alternating current power supply from a fluorescent lighting ballast. A shunt device is provided for selectively shunting the power supply to implement dimming control. A detector is provided for generating a detection signal and for providing the detection signal to the control circuit to operate the shunt device. The detector has a detection circuit for analyzing a voltage at the driver input and generating 5 the detection signal accordingly, when the voltage is detected. In addition, for situations where the voltage detection does not correctly generate the detection signal, a correction circuit generates the detection signal for a time delay from the end of operating the shunt device. This prevents control stability problems at low dimming levels.

Abstract: A retrofit Light Emitting Diode, LED, tube for connecting to a High Frequency, HF, ballast, which LED tube comprises a switchable capacitor arrangement for ensuring that the ballast does not go into over current protection mode, wherein the switching is controlled based on a desired dimming level of the LED tube. The switchable capacitor arrangement is provided in parallel with said input of said rectifier, and comprises at least a first capacitor and a second capacitor in series, and said control circuit is adapted to configure said switchable capacitor arrangement to conduct the AC power and switch at least one of the first capacitor and the second capacitor between the rectifier and the LED array to block the DC power to said LED array.

Abstract: A load driver for driving a load and an LED module are disclosed. In one embodiment, the load driver comprises a converter circuit comprising a controllable switching element configured to be turned on and off and to perform power factor correction for power from a power supply to the load, wherein a control terminal of the controllable switching element is configured for receiving a startup current via the two output terminals, the controllable switching element configured to be turned on by the startup current. The converter circuit further comprises a first inductor, coupled to the power supply at a first end, and to ground at a second end via the controllable switching element, wherein a first one of the output terminals connects to a second end of the first inductor via a diode forwarded from the first inductor, a second one of the output terminals is coupled to the first end of the first inductor.

Abstract: A retrofit Light Emitting Diode, LED, tube for connecting to a High Frequency, HF, ballast, which LED tube comprises a switchable capacitor arrangement for ensuring that the ballast does not go into over current protection mode, wherein the switching is controlled based on a desired dimming level of the LED tube. The switchable capacitor arrangement is provided in parallel with said input of said rectifier, and comprises at least a first capacitor and a second capacitor in series, and said control circuit is adapted to configure said switchable capacitor arrangement to conduct the AC power and switch at least one of the first capacitor and the second capacitor between the rectifier and the LED array to block the DC power to said LED array.

Abstract: There is proposed an interface circuit for connecting an electronic ballast to a lighting arrangement, in which control of a coupling configuration of the interface circuit is dependent upon a frequency of the electronic ballast. In particular, a coupling configuration of the interface circuit is controlled by a control arrangement based on the ballast frequency.

Abstract: The invention describes a coded light modulation arrangement (1), adapted to be connected between a driver (31) and a LED (3), which coded light modulation arrangement (1) comprises input terminals (10) adapted to connect to the driver (31) and to receive a drive current (IDRIVE), an energy storage arrangement comprising a number of energy storage devices (E1, E2); a data input interface (12) 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 (S1, S2) arranged to connect the energy storage devices (E1, E2) 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 (INEG) is diverted from a drive current (IDRIVE) of the LED (3) to the energy storage arrangement; and, in a discharging switch configuration corresponding to the logic high, a positive modulati

Abstract: The invention describes a coded light modulation arrangement (1), adapted to be connected between a driver (31) and a LED (3), which coded light modulation arrangement (1) comprises input terminals (10) adapted to connect to the driver (31) and to receive a drive current (IDRIVE), an energy storage arrangement comprising a number of energy storage devices (E1, E2); a data input interface (12) 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 (S1, S2) arranged to connect the energy storage devices (E1, E2) 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 (INEG) is diverted from a drive current (IDRIVE) of the LED (3) to the energy storage arrangement; and, in a discharging switch configuration corresponding to the logic high, a positive modulati

Abstract: A lighting circuit uses a tapped linear driver architecture in which there are at least two LED types; a first LED type with a first forward voltage, and a second LED type with a second forward voltage at least double the first forward voltage. The first segment of the tapped linear driver comprises more LEDs of the first type than the second type and the last segment comprises more LEDs of the second type than the first type. This arrangement enables a reduction in the number of LEDs needed, but without significantly impacting on the efficiency of the circuit.

Abstract: Presented is a converter circuit having main switching circuiton a primary side of a transformer, for controlling supply of a current to a storage inductor on the primary side when the main switching circuit is conductive. The convertor circuit comprises: a control circuit operatively coupled to the main switching circuit and for controlling the main switching circuit, the control circuit comprising a control capacitor adapted to enable the control circuit and turn off the main switching circuit; an auxiliary inductor magnetically coupled to the storage inductor and adapted to trigger the control circuit to operate and turn off the main switching circuit in response to a voltage change in the storage inductor when the main switching circuit being conductive; and a charging circuit coupled between the auxiliary inductor and the control capacitor and adapted to enable the auxiliary inductor to charge the control capacitor.

Abstract: A lighting circuit uses a tapped linear driver architecture in which there are at least two LED types; a first LED type with a first forward voltage, and a second LED type with a second forward voltage at least double the first forward voltage. The first segment of the tapped linear driver comprises more LEDs of the first type than the second type and the last segment comprises more LEDs of the second type than the first type. This arrangement enables a reduction in the number of LEDs needed, but without significantly impacting on the efficiency of the circuit.

Abstract: 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 (Q1) driven by the input power, and a control circuit (Q2, Q3) for controlling a control current of the main power switch (Q1), wherein the control circuit in (Q2, Q3) is adapted to sense the level of the input power and draw current from a control terminal of the power switch (Q1) 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 (Q2) and a second transistor (Q3), the first transistor (Q2) with a base terminal connected to a circuit position indicative of the voltage amplitude of the input power, the second transistor (Q3) with a base termina

Abstract: 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 (Q1) driven by the input power, and a control circuit (Q2, Q3) for controlling a control current of the main power switch (Q1), wherein the control circuit in (Q2, Q3) is adapted to sense the level of the input power and draw current from a control terminal of the power switch (Q1) 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 (Q2) and a second transistor (Q3), the first transistor (Q2) with a base terminal connected to a circuit position indicative of the voltage amplitude of the input power, the second transistor (Q3) with a base termina

Abstract: Presented is a converter circuit having main switching circuiton a primary side of a transformer, for controlling supply of a current to a storage inductor on the primary side when the main switching circuit is conductive. The convertor circuit comprises: a control circuit operatively coupled to the main switching circuit and for controlling the main switching circuit, the control circuit comprising a control capacitor adapted to enable the control circuit and turn off the main switching circuit; an auxiliary inductor magnetically coupled to the storage inductor and adapted to trigger the control circuit to operate and turn off the main switching circuit in response to a voltage change in the storage inductor when the main switching circuit being conductive; and a charging circuit coupled between the auxiliary inductor and the control capacitor and adapted to enable the auxiliary inductor to charge the control capacitor.