Abstract: A PFC flyback converter topology is disclosed. The topology can be implemented in a single-stage and is particularly useful in driving dimmable solid state light sources in lighting applications, though other applications susceptible to instability at very low loading conditions may also benefit. Stable operation is achieved over a broader range of loading using the converter topology as provided herein. In a dimmable lighting application, stable operation (e.g., flicker-free lighting) is achieved at very low dimming levels (e.g., where the load is less than 10% full load). In some topologies, a serial arrangement including a stabilization network and a switch is connected across the solid state light sources or other load. A microcontroller unit controls the duty cycle of the switch to selectively steer excess current from the solid state light sources to the stabilization circuit, at very low dimming conditions.

Abstract: A multi string controller with independent current setting for each string is designed for solid state lighting applications. This controller can regulate multiple channels of LEDs. Each string may have a different forward voltage and current setting. A constant buck regulator is also integrated inside this controller to regulate the total current, which is fed into the LED output channels. The circuit also contains a feedback loop in order to precisely control the current passing through each string and is immune to transient conditions.

Abstract: An active damping circuit is disclosed, which includes a peak current limiter, a drain source voltage limiter, a turn-on driver, a resistor shunt circuit, and a peak current sensor. The peak current sensor detects a rising edge of an input voltage from a phase cut dimmer by detecting a higher peak current. This drives a collector voltage of a second transistor of the peak current limiter low, which lowers a gate voltage of a first transistor of the peak current sensor, and forces it into a linear operating region, so it functions as a damping resistor. When the peak current sensor detects a decreased peak current, such that the turn-on edge of the input voltage is passed, the second transistor turns off, and the turn-on driver turns the first transistor on, such that the active damping circuit is waiting for a next edge of the input voltage.

Abstract: A multi string controller with independent current setting for each string is designed for solid state lighting applications. This controller can regulate multiple channels of LEDs. Each string may have a different forward voltage and current setting. A constant buck regulator is also integrated inside this controller to regulate the total current, which is fed into the LED output channels. The circuit also contains a feedback loop in order to precisely control the current passing through each string and is immune to transient conditions.

Abstract: An active damping circuit and system including the same are disclosed. The active damping circuit includes a first resistor, a second resistor, a third resistor, a first transistor, a second transistor, a capacitor, and a microcontroller. The first resistor is connected to a base of the first transistor, and to the microcontroller output. The second resistor is connected to a positive voltage, and to a collector of the first transistor and a gate of the second transistor. The third resistor is connected to a logic ground, and to a source of the second transistor. The capacitor is connected to the collector of the first transistor, the second resistor, and the gate of the second transistor. A drain of the second transistor, and the first capacitor, and the second capacitor, and the microcontroller output, are also connected to the logic ground. An emitter of the first transistor is connected to ground.

Abstract: An active damping circuit is disclosed, which includes a peak current limiter, a drain source voltage limiter, a turn-on driver, a resistor shunt circuit, and a peak current sensor. The peak current sensor detects a rising edge of an input voltage from a phase cut dimmer by detecting a higher peak current. This drives a collector voltage of a second transistor of the peak current limiter low, which lowers a gate voltage of a first transistor of the peak current sensor, and forces it into a linear operating region, so it functions as a damping resistor. When the peak current sensor detects a decreased peak current, such that the turn-on edge of the input voltage is passed, the second transistor turns off, and the turn-on driver turns the first transistor on, such that the active damping circuit is waiting for a next edge of the input voltage.

Abstract: An active damping circuit and system including the same are disclosed. The active damping circuit includes a first resistor, a second resistor, a third resistor, a first transistor, a second transistor, a capacitor, and a microcontroller. The first resistor is connected to a base of the first transistor, and to the microcontroller output. The second resistor is connected to a positive voltage, and to a collector of the first transistor and a gate of the second transistor. The third resistor is connected to a logic ground, and to a source of the second transistor. The capacitor is connected to the collector of the first transistor, the second resistor, and the gate of the second transistor. A drain of the second transistor, and the first capacitor, and the second capacitor, and the microcontroller output, are also connected to the logic ground. An emitter of the first transistor is connected to ground.

Abstract: A DC-DC flyback converter includes a transformer and a switching component connected between the transformer and a ground. The switching component controls current flow through the primary winding of the transformer. A snubber circuit is connected between ground and the connection between the transformer and the switching component. The snubber circuit reduces transient voltage spikes across the switching component. A capacitive component of the snubber circuit provides stability for a primary side auxiliary output voltage while maintaining power factor and THD performance.

Abstract: Systems, methods, and computer program products for turn on optimization of a driver for one or more light sources are disclosed. A duty cycle value is selected from a table. The selected duty cycle corresponds to the target output current of the driver and has a corresponding voltage. The selected duty cycle is applied to the driver. An output voltage at the light source is measured, and compared to the corresponding voltage of the selected duty cycle to produce a voltage comparison result. Based on the comparison result, the selection of the duty cycle is adjusted. Additionally, an output current of the light source is measured and compared to the target output current, to produce a current comparison result. An adjustment coefficient is applied to a feedback circuit of the driver based thereon, wherein the feedback circuit adjusts a switching frequency of the driver based on the selected duty cycle.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The ballast is rated at a higher power than the steady state operating power of the lamp. The controller ignites the lamp at a frequency which is less than the steady state operating frequency of the lamp and ignites the lamp at a current which is greater than the steady state operating current of the lamp.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The switch is in a power supply loop of the oscillator and selectively open circuits and close circuits the power supply loop. When the switch close circuits the power supply loop, the oscillator oscillates and provides power to the lamp. When the switch open circuits the power supply loop, the oscillator does not oscillate and does not provide power to the lamp.

Abstract: A PAR38 light source assembly for use with a fixture having PAR38 socket connected to a ballast circuit for generating a ballast voltage. An electrically insulating housing supports a PAR38 screw base and encloses a CMH lamp and a circuit board providing a high voltage to ignite or re-ignite the lamp. The housing supports a reflector a lens wherein the lens, the reflector and the housing form an electrically insulating enclosure so that the PAR38 screw base is the only electrically conductive portion.

Abstract: An integral HID reflector lamp may be formed with an HID held in a reflector. An inner element is mechanically coupled to the reflector. The inner element is formed with a first mechanical coupling to mate with the reflector, a second mechanical coupling to mate with a circuit board, and an electrical coupling to at least electrically couple one of the leads to the circuit board. A circuit board has an edge mechanically coupled to the inner element and electrically connected to the leads by an electrical coupling on the inner element. A heat sink spans at least one side of the circuit board and forming an EMI shielding. An outer cover encloses the heat sink, circuit board, and inner element and coupled to the assembly of the reflector, HID lamp, inner element, and heat sink with each elements of the assembly clipped together.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The ignition method includes enabling the oscillator such that the oscillator provides the lamp with a pulse train comprising a rapid series of short ignition pulses, cools for a period of time, and provides an addition pulse train to the lamp if necessary to ignite the lamp. When the lamp ignites, the ballast maintains enablement of the oscillator.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The switch selectively alters an inductance of the inductor to switch between a first frequency of the oscillator and a second frequency of the oscillator different than the first. The controller monitors a current of a power supply loop of the oscillator and a voltage of the oscillator and determines a duty cycle as a function of the monitored voltage and current. The duty cycle is indicative of the percentage of time that the oscillator is to operate at the first frequency versus the second frequency.

Abstract: An integral HID reflector lamp may be formed with an HID held in a reflector. An inner element is mechanically coupled to the reflector. The inner element is formed with a first mechanical coupling to mate with the reflector, a second mechanical coupling to mate with a circuit board, and an electrical coupling to at least electrically couple one of the leads to the circuit board. A circuit board has an edge mechanically coupled to the inner element and electrically connected to the leads by an electrical coupling on the inner element. A heat sink spans at least one side of the circuit board and forming an EMI shielding. An outer cover encloses the heat sink, circuit board, and inner element and coupled to the assembly of the reflector, HID lamp, inner element, and heat sink with each elements of the assembly clipped together.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The switch selectively tunes and detunes an inductor of the oscillator by altering an inductance of the inductor. When the inductor is tuned, the oscillator oscillates and provides power to the lamp. When the inductor is detuned, the oscillator does not oscillate and does not provide power to the lamp.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The ballast is rated at a higher power than the steady state operating power of the lamp. The controller ignites the lamp at a frequency which is less than the steady state operating frequency of the lamp and ignites the lamp at a current which is greater than the steady state operating current of the lamp.

Abstract: A PAR38 light source assembly for use with a fixture having socket connected to a ballast circuit for generating a ballast voltage. An electrically insulating housing supports a PAR38 screw base and encloses a CMH lamp and a circuit board providing a high voltage to ignite or re-ignite the lamp. The housing supports a reflector a lens wherein the lens, the reflector and the housing form an electrically insulating enclosure so that the PAR38 screw base is the only electrically conductive portion.

Abstract: A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The switch is in a power supply loop of the oscillator and selectively open circuits and close circuits the power supply loop. When the switch close circuits the power supply loop, the oscillator oscillates and provides power to the lamp. When the switch open circuits the power supply loop, the oscillator does not oscillate and does not provide power to the lamp.