Abstract: An illumination stabilization apparatus for a vehicle headlamp is disclosed. The illumination stabilization apparatus supplies stable power to a headlamp using a SEPIC, thus increasing the lifespan of a headlamp, and reducing the dimming of light generated by the headlamp.

Abstract: An incandescent lamp includes a lamp voltage conversion circuit within the lamp and connected to a lamp terminal, where the voltage conversion circuit converts a first line voltage at the lamp terminal to a second RMS load voltage usable by a light emitting element of the lamp. The voltage conversion circuit includes a triac phase-controlled dimming circuit, which in turn includes a voltage controlled resistor that varies a resistance in the phase-controlled dimming circuit as the first voltage varies so as to maintain the second voltage substantially constant. The voltage conversion circuit may be an integrated circuit that is in the lamp base and connected between the lamp terminal and the light emitting element.

Abstract: An apparatus and method are provided for suppressing the input current inrush for a voltage converter in a pre-charge stage. The voltage converter comprises a power input for receiving an input current, a power output for supplying an output voltage for a load, and an output capacitor connected to the power output. In a pre-charge stage, a current limiting device is connected between the power input and the output capacitor to limit the input current to flow therethrough, and a variable current limiting control circuit provides a control signal to the current limiting device to determine a variable maximum value for the input current.

Abstract: An inverter has an inductor, a capacitor, a switching device, a driving circuit and a transformer. A first terminal of the capacitor is connected to the inductor, and the switching device is connected between the first terminal of the capacitor and a ground terminal. The driving circuit is connected to the switching device, wherein the driving circuit is arranged to control the switching device to turn on or turn off; and a primary side of the transformer is connected between a second terminal of the capacitor and the ground terminal.

Abstract: The present invention is disclosed by that the series connected capacitive impedance and inductive impedance are powered by a pulsed power, thereby to produce the bi-directional divided power in series resonance at each impedance, and be rectified by a rectifier device to provide DC power output to drive the unidirectional conducting light emitting diode.

Abstract: A phase-modulated, double-ended, half-bridge topology-based DC-AC converter supplies AC power to a load, such as a cold cathode fluorescent lamp used to back-light a liquid crystal display. First and second converter stages generate respective first and second sinusoidal voltages having the same frequency and amplitude, but having a controlled phase difference therebetween. By employing a voltage controlled delay circuit to control the phase difference between the first and second sinusoidal voltages, the converter is able to vary the amplitude of the composite voltage differential produced across the opposite ends of the load.

Abstract: A control device, which controls a power-converting module that is coupled to a light-emitting component, includes a duration detecting unit and a control signal generator. The duration detecting unit compares the duration of a predetermined logic state of a pulsating input dim control signal with a reference time period. The control signal generator is enabled by the duration detecting unit so as to generate a control signal that enables the power-converting module to generate a drive voltage for driving the light-emitting component when the duration of the predetermined logic state is not longer than the reference time period. The duration detecting unit disables the control signal generator to disable the power-converting module when the duration of the predetermined logic state is longer than the reference time period.

Abstract: A high conversion efficiency inverter circuit by providing the current-mode resonant type efficient in using a power source.

Abstract: A highly stable current-mode resonant inverter circuit operates by detecting resonance current in the secondary side circuit. The inverter circuit comprises a step-up transformer with a secondary winding connected to a secondary side circuit with a capacitive component. The leakage inductance and the secondary winding and the capacitive component compose a series resonant circuit. The inverter circuit is configured to detect a current flowing through the secondary winding or capacitive component in the secondary side circuit, and determine a switching timing in response to the detected current. The determined switching timing allows the inverter circuit to oscillate self-excitedly at a resonance frequency of the series resonant circuit.

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.

Abstract: A method for igniting and operating a high intensity discharge (HID) lamp using an electronic ballast controlled by a ballast microcontroller. An ignition circuit including a parallel capacitive circuit is connected in parallel to the HID lamp. The ignition circuit being resonant at an ignition resonance frequency. An ignition voltage is provided to the HID lamp at the ignition resonance frequency, thereby initiating ignition of the HID lamp. Upon sensing the ignition, the HID lamp is powered at an operation frequency. Both the ignition resonance frequency and the operation frequency are in a high frequency range above fifty kilohertz. The ignition voltage preferably does not include a significant direct current offset The current flowing through the HID lamp is substantially continuous during the transition from providing ignition voltage during the ignition to powering the HID lamp at the operation frequency.

Abstract: A discharge lamp lighting circuit 1 includes a direct current-alternating current converting circuit 3, a starting circuit 4, controlling means 15 for controlling power, switching elements 5H, 5L driven by the controlling means 15 and a series LC resonance circuit (7p, 8, 9). A frequency modulating circuit is provided for restraining acoustic resonance by modulating a frequency of driving the switching element. When a basic frequency related to the drive frequency is equal to or higher than 1 MHz, a modulation width is set to be equal to or higher than 20 kHz.

Abstract: The invention relates to a device for lighting at least one light emitting diode to be supplied with predefined minimum forward voltage and maximum current. It comprises: —voltage supply means for supplying voltage to the light emitting diode, —a pulse generator for generating a cyclic pulse signal having predefined on-times and off-times, —a switch, controlled by the pulse generator to be turned on during said on-times to short-circuit the light emitting diode and turned off during said off-times, —an inductive device for increasing the forward voltage over the light emitting diode when the switch is turned off, so that said forward voltage gets higher that the minimum forward voltage and for decreasing said forward voltage when the switch is turned on, so that the current through the light emitting diode remains below the maximum current.

Abstract: A sequential burst mode regulation system to deliver power to a plurality of loads. In the exemplary embodiments, the system of the present invention generates a plurality of phased pulse width modulated signals from a single pulse width modulated signal, where each of the phased signals regulates power to a respective load. Exemplary circuitry includes a PWM signal generator, and a phase delay array that receives a PWM signal and generates a plurality of phased PWM signals which are used to regulate power to respective loads. A frequency selector circuit can be provided that sets the frequency of the PWM signal using a fixed or variable frequency reference signal.

Abstract: A lamp driving circuit includes a step-up transformer, a detector, and a controller. The step-up transformer includes a primary winding, and a secondary winding configured to cooperate with a discharge lamp to form a tank circuit that generates a tank current. The detector is adapted for detecting current magnitude of current flowing through the discharge lamp, and outputs a detecting signal corresponding to the current magnitude. The controller receives the detecting signal from the detector, and generates a drive signal for driving the step-up transformer. The controller includes a capacitor, and configures a waveform of the drive signal by controlling charging of the capacitor based on a calculation value that corresponds to a frequency of the drive signal, a start-setting value, and a difference between the detecting signal and a current-setting signal.

Abstract: Ignition of a gas discharge lamp 10, which has a gas containing main space and two inner electrodes, of a lighting unit 4 of a lighting system is achieved by the use of a high frequency resonance circuit. The resonance circuit is connected to the inner electrodes and to a supply device 2, which supplies an alternating supply voltage. An outer electrode 22 is arranged near one the inner electrodes and to a node of the resonance circuit. Upon supplying the supply voltage a high voltage alternating burst will be generated at the outer electrode. This will result into a discharge of the gas in the main space. In turn, this will induce a discharge of the remaining gas. Then the frequency of the supply voltage will increase and a small reactive current only will remain to flow through the resonance circuit.

Abstract: A ballast (10) for powering at least one gas discharge lamp (70) in a program start mode comprises an inverter (200), a resonant output circuit (400), and a control circuit (600). During operation of ballast (10), control circuit (600) monitors a voltage within resonant output circuit (400). When the monitored voltage reaches a first specified level that is indicative of sufficient filament preheating, control circuit (600) maintains the inverter operating frequency at a first present value for a preheating period so as to provide preheating of lamp filaments (72,74). Following completion of the preheating period, control circuit (600) allows the inverter operating frequency to decrease. When the monitored voltage reaches a second specified level that is indicative of sufficient ignition voltage, control circuit (600) maintains the inverter operating frequency at a second present value for an ignition period so as to provide ignition of lamp (70).

Abstract: The present invention aims to provide an inrush current limiting resistor for suppressing inrush current, and to avoid an excessive current flowing through the inrush current limiting resistor even if the lamp is operated at a dimmed level by mistake. A compact self-ballasted fluorescent lamp 1 is composed of a holder 20 and a case 30 attached to each other. The case 30 houses therein a lighting unit 50 for operating an arc tube 10. The lighting unit 50 is composed of a rectifier/smoothing circuit module having an electrolytic capacitor 53, an inverter circuit module, and a resonant circuit module having a resonance capacitor 54. The circuit modules are mounted on a printed wiring board 51. An inrush current limiting resistor 62 is connected to the input end of the rectifier/smoothing circuit module and in contact with the electrolytic capacitor 53 and the resonance capacitor 54 at their outer circumferential surfaces.

Abstract: An arrangement for supplying a constant current to at least one LED includes a current source (2; 2a, 2b) with an output capacitor (3) connected across the terminals of the current source. An output inductor (4) is associated with the output capacitor (3) whereby the current supplied flows through the inductor (4). A smoothing resistor (5) is preferably connected in parallel to the output inductor (4).

Abstract: A ballast operates lamps each including a pair of electrodes. A high frequency resonant circuit generates a high frequency bus, the resonant circuit is configured for operational coupling to the electrodes of each lamp, and includes a resonant inductor and a resonant capacitance.

Abstract: An inductively powered gas discharge lamp assembly having a secondary circuit with starter circuitry that provides pre-heating when power is supplied to the secondary circuit at a pre-heat frequency and that provides normal operation when power is supplied to the secondary circuit at an operating frequency. In one embodiment, the starter circuitry includes a pre-heat capacitor connected between the lamp electrodes and an operating capacitor located between the secondary coil and the lamp. The pre-heat capacitor is selected so that the electrical flow path through the pre-heat capacitor has a lesser impedance than the electrical flow path through the gas of the lamp when power is applied to the secondary circuit at the pre-heat frequency, and so that the electrical flow path through the pre-heat capacitor has a greater impedance than the electrical flow path through the gas when power is applied the operating frequency.

Abstract: In a lamp lighting ballast which generates a lamp lighting signal for a lamp, provided is a striation elimination circuit to increase the lumen output frequency for elimination of visual striations which may occur within the lamp. An even harmonic signal generator is configured to generate an even harmonic waveform, and an injection point is configured to receive the even harmonic signal into the lamp lighting system. The injection point is located at a location wherein the even harmonic signal alters the lamp lighting signal from a symmetric signal configuration to a high content even harmonic signal configuration prior to being received by the lamp.

Abstract: This invention provides a signal transmission circuit, a signal output circuit, and a termination method of a signal transmission circuit capable of preventing the re-reflection of the signal at a transmitting node of a transmission path even when an impedance of a signal output circuit does not match a characteristic impedance of a transmission path. On a signal transmission circuit composed of a transmission path, a signal output circuit connected to a transmitting node of the transmission path, and a signal receiver circuit connected to a receiving node of the signal transmission path, in order to prevent the re-reflection of an output signal of a signal output unit at the transmitting node via the receiving node, a correction current generator unit is provided for outputting correction current with a predetermined current amount and at a predetermined timing set in a current amount/timing control section, to the transmitting node.

Abstract: A resonant switching converter comprising a first pair of series connected switches comprising a high side switch and a low side switch coupled across a DC input voltage, there being a first switched node between the switches; a second pair of series connected switches comprising a high side switch and a low side switch coupled across a DC bus, there being a second switched node between the switches; a DC bus capacitor coupled across the DC bus; the first and second switched nodes adapted to have a load coupled therebetween; the high side switch of the first pair of switches supplying current to the load from the DC input voltage, the low side switch of the first pair of switches being switched opposite the high side switch of the first pair of switches and providing a re-circulation path to allow bi-directional current flow through the load; the high side switch of the second pair of switches supplying current to the load from the DC bus capacitor, the low side switch of the second pair of switches being swi

Abstract: A ballast control circuit for multiple lamps comprising a ballast control circuit for driving two series connected switches of a lamp ballast connected across a supply potential and having a switched node between the switches; the switched node adapted to be connected to an output circuit comprising a plurality of parallel connected lamps; the control circuit comprising an oscillator, the output circuit comprising the plurality of parallel connected lamps including inductive and capacitive components and having a resonance frequency that is dependent on the number of lamps in the output circuit; a lamp output voltage being developed across the output circuit; further comprising a feedback circuit for controlling the oscillator whereby the oscillator sweeps from a first frequency above resonance to a lower frequency closer to resonance such that the output voltage increases to a potential above a lamp ignition threshold, thereby igniting at least one lamp; the feedback circuit controlling the oscillator whereb

Abstract: An apparatus and method for driving a halogen lamp. A driving circuit is provided that is operable near a series resonance frequency. The driving circuit is coupled to the lamp in a series configuration. During startup, the circuit is driven above resonance. After the lamp has warmed up, the circuit is driven substantially at resonance. A controller is coupled to the driving circuit. The controller is operable to control the frequency of operation of the driving circuit.

Abstract: A portable fluorescent task lamp comprising at least two fluorescent bulbs of any wattage up to forty Watts and of either a non-starting type or a self-starting type; and an electronic ballast circuit for use therewith including an SPST function switch disposed in series with each fluorescent bulb, wherein the fluorescent bulbs may be ignited and sustained in illumination in parallel, simultaneously or individually, as determined by the respective SPST switches.

Abstract: An anti-cycling luminaire control system may detect repeated lamp-off conditions and interrupt power to the lamp and provide an indication of lamp cycling after a predetermined number of lamp-off conditions has been detected. The control system also provides a cool-off period after a lamp-off cycling event is detected during which time restarting of the lamp is inhibited. If the lamp does not restart after multiple restart attempts and cool-off periods, the system determines that a fault condition exists, and may provide a fault alert. The system may provide for shut-off or dimming of the lamp during the night after a portion of the night has passed. This delayed turn-off may be varied according to the length of the night. Starting and dimming the lamp at a zero voltage crossing of the line current can reduce stress on luminaire and control system components and reduce maintenance.

Abstract: The invention relates to a driving apparatus for a CCFL capable of providing a high output voltage necessary for an open lamp and thereby satisfying a voltage standard required to drive the lamp. In the driving apparatus, an inverter made of a switching circuit of a half-bridge structure is used to generate current for driving the lamp. If the lamp is open, a tuning capacitor current of an oscillator, which provides a reference clock for driving a switch of the inverter is incremented so that a clock frequency which is a basis for a switching speed of the inverter is boosted. This consequently increases the switching speed of the inverter and then an output voltage.

Abstract: The invention relates to a driving apparatus for a CCFL capable of easily providing a high output required to start the lamp. In the apparatus, an oscillator provides a reference signal in accordance with a lamp-on condition or a lamp-out condition. According to the invention, a tuning capacitor current of an oscillator is increased so that a switching speed of an inverter becomes faster in the lamp-out condition than in the lamp-on condition, thereby satisfying the voltage required to start the lamp.

Abstract: Power taken inductively from the alternating current in a track is received by a resonant circuit which is output controlled by a switching circuit asynchronous with the frequency of the power supply. The switch on and off time is controlled to regulate the output power and the circuit is such that on light loads the resonant circuit decouples from the track.

Abstract: A ballast lamp circuit and method of operation is disclosed. The ballast lamp circuit comprising an inverter circuit and cathode heating circuit, wherein a lamp current, generated by the inverter circuit, is inversely proportional to a lamp cathode voltage generated by the cathode heating circuit.

Abstract: A power control circuit includes a power switch unit operable so as to enable and disable supply of an input voltage from an external power source to an LC circuit, a voltage detecting unit for generating a first voltage signal in accordance with an output voltage applied to a load and outputted by the LC circuit, and a current detecting unit for generating a second voltage signal in accordance with a current flowing through the power switch unit. A driver receives a pulse width modulation signal from a comparator in accordance with a comparison result between a summation of the first and second voltage signals and a reference voltage, and outputs a driving signal to a control input unit of the power switch unit so as to control a duty cycle of the power switch unit, thereby controlling rated power supplied to the load to correspond to the reference voltage.

Abstract: A pulse width modulation inverter circuit is provided. The circuit includes a power switch driver, a power switch, a transformer unit, a feedback detector unit, and a voltage control oscillator. The circuit is electrically coupled to the DC power source to drive a load. The circuit adjusts the pulse width of the signal outputted from the power switch driver according to the voltage inputted to the DC power source. Accordingly, the circuit can maintain a fixed input voltage received by the fluorescent tube. Thus, the high input voltage but low output phenomenon can be avoided.

Abstract: A reversible dimmer device of gas discharge lamp and a control method for light adjusting thereof are proposed, in which a power switch on the wall or on an appliance is used to control actions of at least of a gas discharge lamp. When the power switch is turned on, a power signal is provided to drive the gas discharge lamp to produce a stable light source. The power switch is then fast pressed to make sure the times and timing of off-on switching so that a logic control circuit can output a logic control command. A frequency modulation control circuit is then used to adjust a power parameter according to the logic control command so that a variable frequency resonance drive circuit can vary the drive frequency of the power signal based on the power parameter. The gas discharge lamp can thus produce different luminance or different luminous effects.

Abstract: A discharge lamp controlling apparatus includes a detector for detecting a discharge condition of a discharge lamp; a frequency changing unit for gradually changing a frequency of a voltage to be applied to the discharge lamp until the discharge condition reaches a predetermined lighting condition; and a voltage controller for controlling the voltage to be applied to the discharge lamp on the basis of the frequency changed by the frequency changing unit.

Abstract: A resonance load circuit is supplied with the high-frequency voltage from the inverter circuit, and includes an inductor, a capacitor and a discharge lamp. The resonance load circuit is so that a declination with respect to the lighting frequency fs is set to a range from ?20° to 40° in impedance when the discharge lamp is operating at rating. The CPU continuously generates a pulse voltage for driving on and off the switch elements at a cycle shorter than a lighting cycle of the discharge lamp based on program data and data stored in a memory, and makes pulse-width modulation with respect to an on-state width of the pulse voltage in accordance with a waveform change of a sinusoidal voltage corresponding to the lighting cycle, and further, supplies an approximately sinusoidal current to the discharge lamp using a high-frequency output from the inverter circuit.

Abstract: A discharge lamp lighting circuit includes an open protection circuit. The discharge lamp lighting circuit includes an open protection circuit and an over-voltage detecting circuit. The open protection circuit detects whether any of the discharge lamps are unlit, and sends a voltage control signal to a control circuit if one of the discharge lamps is not lit, whereby the control circuit sends a pulse signal to a buck converter according to the voltage control signal, and the buck converter generates and outputs a DC voltage according to the pulse signal. If the DC voltage from the buck converter reaches a predetermined voltage, the over-voltage detecting circuit conducts and sends a voltage control signal to the control circuit, and the control circuit ceases operating according to the voltage control signal. Consequently, damage to the other normal discharge lamps is prevented.

Abstract: A power converter includes a control device (28) for a switching power converter (10), a switching power converter and a method of controlling a switch in a power converter for reducing audible noise. The power converter includes the control device (28) and at least one switch (26) for regulating the power conversion. The control device (28) includes a timer (45) for monitoring a switching frequency of the switch (26) to indicate when the frequency has dropped to a certain level, and a gate driving circuit (32) connected to the timer and arranged to regulate the switching of the switch in dependence of the indication from the timer, so that the frequency rises above the certain level in order to reduce generation of audible noise.

Abstract: A high intensity discharge (HID) lamp electronics controller including a reverse protection circuit and a control protection module. The control protection module includes an under/over voltage protection circuit and an open-circuit and short-circuit protection circuit.

Abstract: A discharge lamp lighting circuit has a structure of a voltage resonance type including a transformer and a switching element to be provided on a primary side thereof as a DC—DC converting circuit for converting a DC input voltage into a desirable DC voltage. The lighting circuit further includes a control circuit serving to ON/OFF control the switching element, thereby controlling an output voltage Vout of the DC—DC converting circuit, and has a function of a current limitation related to the switching element. In the lighting circuit, if the output voltage Vout is raised, a current flowing to the switching element is limited to be decreased. Consequently, a voltage applied to the switching element can be suppressed, and furthermore, the winding ratio of the transformer does not need to be increased. Accordingly, it is possible to prevent an electrical efficiency from being deteriorated.

Abstract: A DC-AC converter in a half bridge configuration is used for operation with high pressure discharge lamps as well as low pressure discharge lamps. The converter consists in two switches (T1-T2) serially connected through a first series of diodes (D1, D2) and a second series of diodes (D3,D4) to which at their middle points (N1, N2) a first and a second lamp loads (L1,L2,LA1,LA2) are connected. Furthermore, the second terminals of the lamp loads are connected to the middle point of a series of capacitors (C3,C4) which are also connected to the terminals (Ki,K2) of the supply voltage source. The converter includes also four diodes (D5,D6,D7,D8) which shunt the switches (T1,T2) and their respective series of diodes (D1,D2,D3,D4). The switches (T1,T2) are controlled by a controller (CC) which renders alternatively conductive at low frequency the two switches (Ti,T2).

Abstract: A circuit for driving cold cathode tubes and external electrode fluorescent lamps uses only 19–26 watts of power. A steady square wave oscillator generator sets a running frequency for the circuit. A high voltage inductor or high voltage/high frequency transformer in combination with a current limiting capacitor, the lamp and two low resonance value capacitors in series are set and tuned to the oscillation frequency to achieve resonance with the oscillator. The circuit requires an input that has been capacitively and inductively filtered to eliminate harmonic noise in and out of the input line. A thermal shutdown feedback circuit monitors temperature of the circuit. Further, a non-inductive or non-capacitive loading lamp detection feedback and a lamp disconnect driver eliminates false disconnects at start up due to cold bulbs and allows all lamps running on the circuit to continue operation if one is disconnected.

Abstract: An interface circuit suitable for operating capacitive loads such as electric ballasts for lamps at a mains supply circuit, in particular a phase gating dimmer. The interface circuit short-circuits the load input if the mains supply circuit does not carry out a load supply.

Abstract: A lighting apparatus of high intensity discharge lamp comprises a DC power source, a series connection of a first and a second transistors; a series connection of a first and a second capacitors connected in parallel with the series connection of the transistors; a series connection including at least an inductor and a discharge lamp connected between a connection point of the transistors and another connection point of the capacitors, and a control circuit for switching on and off of the transistors so as to supply electric power to the discharge lamp. A voltage of the first capacitor is set to be higher than that of the second capacitor corresponding to the capacitances of the first and second capacitors. Thus, the pulse height in negative or positive phase of the rectangular alternating voltage applied to the discharge lamp can be increased without increasing the output voltage from the DC power source.

Abstract: A protection circuit for an HID dimming circuit is provided. A resistive component limits the initial current after a relay closes and current flows from a charged capacitor to a second capacitor. An inductive component limits the rate of change of current through the circuit. A voltage limited device limits voltage across the contacts of a solid state relay. The circuit is preferably formed in a small module that is adapted to be plugged into an HID lighting device.

Abstract: An AC to AC power conversion apparatus with constant power feeding characteristics to fluorescent lamp or FD lamp is described. The constant power characteristic is achieved by discontinuous mode operation of capacitor coupled in series with the load. Packets of energy are pumped out to the load in each switching cycle, regardless of the resonant characteristics. The dependence of the input power on the square of the supply voltage make the input resistive and produces good power factor automatically. The lamp load is dimmable by external phase control dimmer like resistive incandescent lamps. Multiple lamp loads with different power rating can be integrated by adding more sets of said capacitors and associated components.

Abstract: A method and apparatus for operating a light assembly with fewer peripheral devices than is currently required is presented. The apparatus of the invention includes a lamp unit, a current restricting unit coupled to the lamp unit, and a current sensing unit that is coupled to the current restricting unit. Upon detecting a current output exceeding a predetermined magnitude for at least a predetermined time period, the current restricting unit increases the load on one of the lamps. The current sensing unit senses the output from each of the lamps as modified by the current restricting unit, and sums the outputs to determine a total current flow through the lamps. A current control unit that is coupled to the current sensing unit uses the total current flow to adjust the current input to the lamps.

Abstract: The present invention provides an electronic ballast for a high intensity discharge lamp such as a metal halide lamp. The ballast includes an inverter and a resonant circuit with an ignition capacitor between the resonant circuit and the lamp. The ignition capacitor serves to provide the necessary start-up energy and also serves to provide a low impedance discharge path. A single ignition capacitor may be sufficient, but if a long cable is used to connect the lamp to the ballast, then two ignition capacitors in parallel at opposite ends of the cable may be used. The ballast further provides means for monitoring and controlling lamp power by monitoring a nominally constant dc link voltage, and means for detecting short-circuit and open circuit conditions. A retrial mechanism is provided in the event of the lamp failing to ignite that includes a temporary disabling of the inverter in order to keep the rms lamp voltage low.

Abstract: A discharge lamp starter includes a DC/DC converter. The DC/DC converter includes a forward section for producing a first output voltage that is determined by a power supply voltage and a turn ratio of a transformer, and a flyback section for producing a second output voltage that is determined by an inductance of a primary winding of the transformer and a current flowing through the primary winding. The DC/DC converter generates its output voltage by adding the first output voltage and the second output voltage. The configuration can reduce the size of the discharge lamp starter.