摘要:
A lamp lighting apparatus has a discharge drive circuit for supplying discharge current to the lamp, a voltage conversion circuit for boosting voltage from DC power and supplying the boosted voltage to the discharge drive circuit, and an arc discharge detecting circuit for detecting that a state of discharge of the lamp changes to arc discharge, and outputting an arc discharge transition signal to the voltage conversion circuit, wherein when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge does not take place, the voltage conversion circuit supplies a first voltage or higher to the discharge drive circuit, and when the voltage conversion circuit receives the arc discharge transition signal which shows that the transition to the arc discharge takes place, the voltage conversion circuit supplies a second voltage lower than the first voltage to the discharge drive circuit.
摘要:
In an optimum frequency detection sequence of a discharge lamp, the frequency control circuit performs a sweep operation in which, while the frequency control circuit monitors a syntonization degree signal, a frequency control signal is changed, so that frequency is changed, starting from either an upper or lower limit frequency of a periodic driving circuit, in a range that does not exceed the other frequency, wherein after completion of the sweep operation, the frequency control circuit determines a value of the frequency control signal corresponding to a resonance frequency of the resonant circuit, and inputs the value into a frequency driving circuit, wherein at least in a period of the sweep operation, an inverter receives power supply from a sweep time power supply circuit for supplying electric power with constant supply capability, which is limited to a range in which breakdown does not occur in the discharge lamp.
摘要:
A discharge lamp lighting apparatus for lighting a discharge lamp, comprises an inverter which reverses a polarity of an output voltage and applies alternating voltage to the discharge lamp, and an inverter control circuit which generates an inverter control signal defining a polarity reversal operation of the inverter, based on a polarity reversal timing signal, wherein when the number of polarity reversals in one cycle of the polarity reversal timing signal is even, the inverter control circuit intermittently performs a first operation in which successive pulse-like part of the polarity reversal operation based on the polarity reversal timing signal is disregarded by odd number of times.
摘要:
A low cost DC—DC converter which facilitates a reduction of the switching loss in a wide, variable range of the continuity ratio of the main switching device includes a direct current source; an ON-OFF-controllable main switching device; a main coil which is series connected to the main switching device; a fly-wheel diode which is arranged such that the induction current of the above described main coil flows when the main switching device is shifted into the OFF state; a smoothing capacitor for smoothing the output of the main coil; an auxiliary coil, a resonant capacitor and an ON-OFF-controllable auxiliary switching device. The main switching device and the auxiliary switching device are controlled such that each are alternatively shifted into the ON state such that the main switching device is shifted into the ON state within a given time after the auxiliary switching device has been shifted into the OFF state.
摘要:
A discharge lamp lighting apparatus for lighting a discharge lamp where a voltage generated in a secondary side winding can be superimposed on an output voltage of an inverter and is impressed between electrodes, where while a periodic drive circuit generates an inverter drive signal so that frequency of the inverter becomes a start-up initial frequency, electric supply control circuit controls a power supply circuit to output no-load opening voltage, where the frequency of the inverter gradually decreases until reaching a first threshold frequency from the start-up initial frequency, where when the frequency of the inverter reaches the first threshold frequency, the periodic drive circuit generates the inverter drive signal so that the frequency of the inverter becomes stable lighting frequency, and where the electric supply control circuit controls the power supply circuit to output current which is sufficient to maintain electric discharge of the discharge lamp.
摘要:
In a discharge lamp lighting apparatus, increase modulation on lamp current with a pulse is carried out according to a modulation signal. At a start-up of the discharge lamp or immediately thereafter, the increase modulation is restrained, and in a lighting steady state of the discharge lamp, the restraining of the increase modulation is released, and wherein when the restraining of the increase modulation is released, in a transition period from immediately after the start-up of the discharge lamp to the lighting steady state, the restraining of increase modulation is gradually released.
摘要:
A low cost DC-DC converter facilitates a reduction of the switching loss in the wide, variable range of the continuity ratio for a main switching device. The DC-DC converter includes a direct current source, an ON-OFF-controllable main switching device, a main coil which is series connected to the main switching device, a fly-wheel diode which is arranged such that the induction current of the main coil flows when the main switching device is shifted into the OFF state, and a smoothing capacitor for smoothing the output of the main coil, Also included is an auxiliary transformer with a primary winding as a direct current source and a secondary winding. The main switching device and the auxiliary switching device are controlled such that they are shifted alternatively into the ON state, and the main switching device, is shifted into the ON state a given time after the auxiliary switching device has been shifted into the OFF state.
摘要:
In a discharge lamp lighting apparatus, increase modulation on lamp current with a pulse is carried out according to a modulation signal. At a start-up of the discharge lamp or immediately thereafter, the increase modulation is restrained, and in a lighting steady state of the discharge lamp, the restraining of the increase modulation is released, and wherein when the restraining of the increase modulation is released, in a transition period from immediately after the start-up of the discharge lamp to the lighting steady state, the restraining of increase modulation is gradually released.
摘要:
The present discharge lamp lighting device is capable of rapid modulation in which a lamp current is rapidly reduced and rapidly restored. The current control circuit is provided to perform specific current control such that the brightness of a lamp is reduced by a predetermined percentage without being affected by a variation or change in lamp voltage over time, thereby reducing a lamp current.
摘要:
A DC-DC converter which accomplishes a reduction of the switching loss in the wide, variable range of the continuity ratio of the main switching device includes a direct current source, an ON-OFF-controllable main switching device, a main coil which is series connected to the main switching device, a fly-wheel diode which is arranged such that the induction current of the above described main coil flows when the main switching device is shifted into the OFF state, a smoothing capacitor for smoothing the output of the main coil, an auxiliary coil, a resonant capacitor and an ON-OFF-controllable auxiliary switching device, in which the auxiliary coil and the resonant capacitor are series-connected to form a LC series connection. Further, the LC series connection, the main switching device and the fly-wheel diode are also series connected, with the auxiliary switching device being connected in parallel to the LC series connection.