Abstract: LED devices are provided that include LED chips on LED chip carriers. The LED device can in turn be housed in a package, such as a small-outline transistor (SOT) package or a radial LED device package. A single LED device or a serial connection of a plurality of such LED devices can be operated directly from an AC (line) voltage or a rectified version thereof. In some example embodiments, switching circuitry is integrated into the LED chip carrier for controlling current flow through the LED(s) in response to, for example, a brightness regulating control signal. Numerous example embodiments of the monolithic LED devices are provided, including manufacturing processes as well as various example packages for such LED devices.

Abstract: A system for directly driving light emitting diodes (LEDs). A string of LEDs is coupled across an input voltage and includes a plurality of separate groups of LEDs. Each of a plurality of switches is coupled in parallel with an associated one of the groups of LEDs for controlling current flow through the associated group of LEDs in response to a control signal from a controller circuit. A switch protection circuit is associated with at least one of the switches. The switch protection circuit is configured to place the switch into a conducting state in the event of failure of an LED in the associated group of LEDs.

Abstract: A system for directly driving light emitting diodes (LEDs). A string of LEDs is coupled across an input voltage and includes a plurality of separate groups of LEDs. Each of a plurality of switches is coupled in parallel with an associated one of the groups of LEDs for controlling current flow through the associated group of LEDs in response to a control signal from a controller circuit. A switch protection circuit is associated with at least one of the switches. The switch protection circuit is configured to place the switch into a conducting state in the event of failure of an LED in the associated group of LEDs.

Abstract: An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125 kHz to 150 kHz and the high frequency modulation being a frequency f2 in a range of 230 kHz to 300 kHz, where f2?f1 is at least 0.4*f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.

Abstract: An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125 kHz to 150 kHz and the high frequency modulation being a frequency f2 in a range of 230 kHz to 300 kHz, where f2?f1 is at least 0.4*f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.

Abstract: An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125 kHz to 150 kHz and the high frequency modulation being a frequency f2 in a range of 230 kHz to 300 kHz, where f2-f1 is at least 0.4*f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.

Abstract: An electronic control gear for a HID lamp receives an input signal for operating the lamp and frequency modulates the input signal to generate a frequency modulated output signal that drives an arc of the lamp. The frequency modulation of the output signal sweeps continuously between a low frequency modulation and a high frequency modulation, the low frequency modulation being a frequency f1 in a range of 125 kHz to 150 kHz and the high frequency modulation being a frequency f2 in a range of 230 kHz to 300 kHz, where f2-f1 is at least 0.4*f1. A power amplifier changes an amplitude of the frequency modulated output signal during the low frequency modulations so that a current amplitude of the frequency modulated output signal is substantially constant, and a variable gain transformer adjusts a voltage of the frequency modulated output signal during starting of the lamp.

Abstract: A circuit for controlling current during run-up of a high pressure discharge lamp (140) comprises a buck converter (120) for generating a buck current to drive the high pressure discharge lamp and a control circuit (202) coupled to the buck converter (120) for varying the duty cycle of the buck current during run-up is disclosed. A method for controlling current in an electronic ballast during run-up of a high pressure discharge lamp comprises steps of detecting (501) lamp ignition, providing (502) a buck current to drive the lamp, and varying (504) the duty cycle of the buck current during run-up to control (506) the current in the lamp is also disclosed.