Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: A half bridge resonant converter comprises a half bridge inverter having a high side switch and a low side switch with an output defined from a node between the high side switch and the low side switch. The output connects to a resonant circuit. There are separate control circuits for generating the gate drive signals for controlling the switching of the high side switch and low side switch, in dependence on an electrical feedback parameter, each with different reference voltage supplies.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: The present invention relates to an LED retrofit lamp (1) for being connected to a high frequency electronic ballast (26), the high frequency electronic ballast (26) being adapted for providing a voltage and a current to the LED retrofit lamp (1). The LED retrofit lamp (1) comprises an LED unit (4), an adapting unit (30) for adapting the voltage and the current provided by the high frequency electronic ballast (26) to a voltage and a current for operating the LED unit (4), a detecting unit (40) for detecting an electrical value that depends on the current provided by the high frequency electronic ballast (26), and a ballast protection unit (60) for performing, in dependence of the detected electrical value, an operation for protecting the high frequency electronic ballast (26) from an overcurrent situation. This allows avoiding an unsafe situation, such as when the high frequency electronic ballast (26) is overheated.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: A half bridge resonant converter comprises a half bridge inverter having a high side switch and a low side switch with an output defined from a node between the high side switch and the low side switch. The output connects to a resonant circuit. There are separate control circuits for generating the gate drive signals for controlling the switching of the high side switch and low side switch, in dependence on an electrical feedback parameter, each with different reference voltage supplies.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: Various improvements are provided to resonant DC/DC and AC/DC converter circuit. The improvements are of particular interest for LLC circuits. Some examples relate to self-oscillating circuit and others relate to converter circuits with frequency control, for example for power factor correction, driven by an oscillator.

Abstract: The invention relates to LED replacement lamp suitable for operation with a high frequency fluorescent lamp ballast, comprising—a LED load (LS) comprising a series arrangement of LEDs, —a first lamp end circuit comprising—a first lamp pin (LP1) and a second lamp pin (LP2) for connection to a first lamp connection terminal comprised in the high frequency fluorescent lamp ballast, —a first rectifier (D1-D4; D1, D2) equipped with at least one input terminal coupled to the second lamp pin and with first and second output terminals coupled to respective ends of the LED load, the first rectifier comprising at least two diodes, one of which is shunted by a first capacitor (C1), —a second lamp end circuit comprising—a third lamp pin (LP3) and a fourth lamp pin (LP4) for connection to a second lamp connection terminal comprised in the high frequency fluorescent lamp ballast, —a second rectifier (D5-D8, D5, D6) equipped with at least one input terminal coupled to the fourth lamp pin and with first and second output ter

Abstract: A driver circuit includes: a rectifier for exchanging a first current signal having a first frequency with an active fluorescent ballast, and for supplying a second current signal to a load which includes at least one light emitting diode; a switch circuit coupled to or forming part of the rectifier and configured to control an amount of power supplied to the load; and a controller configured to control the switch circuit. The switching frequency of the switch circuit is less than or equal to twice the first frequency. The controller is configured to synchronize the switching frequency of the switch circuit and the switching frequency of the active electronic ballast, which is equal to the first frequency.

Abstract: The present invention relates to an LED retrofit lamp (1) for being connected to a high frequency electronic ballast (26), the high frequency electronic ballast (26) being adapted for providing a voltage and a current to the LED retrofit lamp (1). The LED retrofit lamp (1) comprises an LED unit (4), an adapting unit (30) for adapting the voltage and the current provided by the high frequency electronic ballast (26) to a voltage and a current for operating the LED unit (4), a detecting unit (40) for detecting an electrical value that depends on the current provided by the high frequency electronic ballast (26), and a ballast protection unit (60) for performing, in dependence of the detected electrical value, an operation for protecting the high frequency electronic ballast (26) from an overcurrent situation. This allows avoiding an unsafe situation, such as when the high frequency electronic ballast (26) is overheated.

Abstract: A lighting device has a plurality of LEDs of at least two types connected in series. At least one of the LEDs of the first type and LEDs of the second type is connected in parallel to a resistor assembly, such that the temperature-dependent resistance of the resistor assembly stabilizes a ratio of luminous flux output at different junction temperatures of the LEDs.

Abstract: In a lighting device, sets of LEDs are employed using the natural characteristics of the LEDs to resemble incandescent lamp behavior when dimmed, thereby obviating the need for sophisticated controls. A first set of at least one LED produces light with a first color temperature, and a second set of at least one LED produces light with a second color temperature. The first set and the second set are connected in series, or the first set and the second set are connected in parallel, possibly with a resistive element in series with the first or the second set. The first set and the second set differ in temperature behavior, or have different dynamic electrical resistance. In various embodiments, the sum of the currents provided to the first and second sets may be substantially equal to a magnitude of an input current.

Abstract: The invention relates to LED replacement lamp suitable for operation with a high frequency fluorescent lamp ballast, comprising—a LED load (LS) comprising a series arrangement of LEDs,—a first lamp end circuit comprising—a first lamp pin (LP1) and a second lamp pin (LP2) for connection to a first lamp connection terminal comprised in the high frequency fluorescent lamp ballast,—a first rectifier (D1-D4; D1,D2) equipped with at least one input terminal coupled to the second lamp pin and with first and second output terminals coupled to respective ends of the LED load, the first rectifier comprising at least two diodes, one of which is shunted by a first capacitor (C1),—a second lamp end circuit comprising—a third lamp pin (LP3) and a fourth lamp pin (LP4) for connection to a second lamp connection terminal comprised in the high frequency fluorescent lamp ballast,—a second rectifier (D5-D8, D5, D6) equipped with at least one input terminal coupled to the fourth lamp pin and with first and second output terminal