An adaptive inductive ballast is provided with the capability to communicate with a remote device powered by the ballast. To improve the operation of the ballast, the ballast changes its operating characteristics based upon information received from the remote device. Further, the ballast may provide a path for the remote device to communicate with device other than the adaptive inductive ballast.

Adaptive inductive power supply with communication

A contactless power supply has a dynamically configurable tank circuit powered by an inverter. The contactless power supply is inductively coupled to one or more loads. The inverter is connected to a DC power source. When loads are added or removed from the system, the contactless power supply is capable of modifying the resonant frequency of the tank circuit, the inverter frequency, the inverter duty cycle or the rail voltage of the DC power source.

Adaptive inductive power supply

A ballast circuit is disclosed for inductively providing power to a load. The ballast circuit includes an oscillator, a driver, a switching circuit, a resonant tank circuit and a current sensing circuit. The current sensing circuit provides a current feedback signal to the oscillator that is representative of the current in the resonant tank circuit. The current feedback signal drives the frequency of the ballast circuit causing the ballast circuit to seek resonance. The ballast circuit preferably includes a current limit circuit that is inductively coupled to the resonant tank circuit. The current limit circuit disables the ballast circuit when the current in the ballast circuit exceeds a predetermined threshold or falls outside a predetermined range.

Inductively coupled ballast circuit

A discharge lamp lighting circuit facilitates carrying out re-ignition and addresses a problem than can arise due to an influence of a capacitor in an auxiliary lighting circuit. A driving voltage generating portion supplies an AC driving voltage to a discharge lamp to be a driving target. An auxiliary lighting circuit is provided on a terminal side of the discharge lamp. An auxiliary lighting capacitor, an auxiliary lighting resistor and a switch are provided in series between the terminal of the discharge lamp and a fixed voltage terminal. A control circuit controls a conducting state of the switch. The switch is brought into an ON state before the discharge lamp is turned ON, and is brought into an OFF state after the discharge lamp is turned ON.

Discharge lamp lighting circuit

A lighting circuit for a vehicular discharge lamp comprises a DC-to-AC converter, a lamp voltage detector, a lamp current detector, a voltage-current controller, and a power change reducing means. The DC-to-AC converter converts a DC voltage into an AC voltage and supplies it to the discharge lamp. The lamp voltage detector acquires a detection signal concerning a lamp voltage of the discharge lamp. The lamp current detector acquires a detection signal concerning a lamp current of the discharge lamp. The voltage-current controller produces a lamp current controller instruction signal generated with respect to the lamp voltage upon reception of the detection signal from the lamp voltage detector, and supplies a control signal to the DC-to-AC converter so as to minimize differences between the instruction signal and the detection signal from the lamp current detector, thereby controlling the output voltage of the DC-to-AC converter. This controller has at least a lighting acceleration area for producing the lamp-current control instruction signal to permit supply of greater power than rated power of the discharge lamp and a steady power control area for performing steady power control of the discharge lamp with the rated power, as a control area based on lamp voltage-lamp current characteristic. The power change reducing means suppresses a change in power supply to the discharge lamp with respect to the lamp voltage at a time of transition to the steady power control area from the lighting acceleration area, thereby shortening the time required for flux of light from the discharge lamp to become stable.

Lighting circuit for vehicular discharge lamp

An illumination device which can dim or vanish a discharge lamp at the end of its service life without using any complex protective circuit even with a discharge lamp in the shape of a fine tube. A high frequency is supplied by an inverter circuit (4) to a load circuit (5) including a discharge lamp (FL), an inductance (L1) and a capacitance (C1), thus carrying out full lighting or dimming of the discharge lamp (FL). At the time of full lighting, load characteristics of relatively low open voltage and large short-circuit current are provided to the load circuit. At the time of dimming, load characteristics of relatively high open voltage and small short-circuit current are provided. When the service life of the discharge lamp (FL) comes to an end at the time of full lighting, the lamp voltage becomes higher than the open voltage of the load circuit (5) and the discharge lamp (FL) vanishes. When the service life comes to an end at the time of dimming, full lighting is started. When the service life then comes to an end, the discharge lamp (FL) vanishes. Since no abnormal temperature rise occurs near an electrode, a glass bulb, a base, and a socket are not melted.

Discharge lamp lighting device and illumination device

A discharge lamp lighting device includes a pair of main switching transistors (Q1a, Q1b) and a feedback transformer (T1). Each of the main switching tran­sistors (Q1a, Q1b) has a control electrode to form a push-pull circuit and which is switched on and off responsive to a given oscillating frequency. The feedback transformer (T1) has a pair of drive windings and serves to positively feed back the output of the push-pull circuit to each of the control electrodes of the paired main switching transistors (Q1a, Q1b). A first control circuit is connected to each of the bases of the main switching transistors and includes a variable impedance element (Q3a, Q3b) to control the oscillating frequency by varying the impedance of this variable impedance element (Q3a, Q3b). A second control circuit (LS) has a level shift circuit and serves to control the level of signal applied to the first control circuit so as to change the impedance of the variable impedance element (Q3a, Q3b) so that the on-off opera­tion of each of the paired main switching transistors (Q1a, Q1b) can be controlled.

Discharge lamp lighting device having level shift control function

A rectification device (4) rectifies an input voltage from an AC power source. First and second switching devices (5, 6) are arranged between a pair of output terminals of the rectification device (4) and alternately turned on/off. A series circuit of a first capacitor (8) and an inductor (7-1) is arranged between the two terminals of one of the first and second switching devices (5, 6) so as to perform a smoothing operation with respect to the frequency of an output from the rectification device (5, 6). A second capacitor (11) serves to form a resonance circuit in cooperation with the inductor (7-1) in accordance with the ON/OFF operations of the first and second switching devices (5, 6). The capacitance of the second capacitor (11) is smaller than that of the first capacitor (8).

Power supply apparatus having high power-factor and low distortion-factor characteristics

In a discharge lamp lighting apparatus of this invention, an AC voltage of a commercial AC power source (12) is full-wave-rectified by a rectifier (14), and this full-wave-rectified AC is smoothed by a smoothing circuit (16) connected to the output terminal of the rectifier (14). An inverter (38) is operated by a series resonance circuit constituted by a resonant choke coil (58) and a capacitor (60) and connected to the output terminal of the rectifier (14) and field-effect transistors (38, 40) connected to this series resonance circuit. By the operation of the inverter (36), a high-frequency AC is induced in an output winding (70) of a boosting transformer (66) having an input winding (68) connected in parallel with the capacitor (60) of the series resonance circuit, and discharge lamps (72₁, 72₂) are turned on.

Discharge lamp lighting apparatus

An apparatus for operating a discharge lamp is disclosed in which a voltage supplied from a commercial alternating current source is fed to a feedback-controlled, saturable current transformer having a primary winding, secondary windings and control winding and to a self-excited inverter circuit having a rectifier circuit. The discharge lame is lit upon receipt of an AC output obtained through reconversion by the inverter circuit. An impedance circuit varies an impedance so as to control a current in the control winding. The current in the control winding varies in accordance with a varied impedance to vary a saturation time of the variable current transformer in the inverter circuit and hence an output of the inverter circuit.

Tsutomu Kakitani

Papers

Discharge lamp lighting device and illumination device

Discharge lamp lighting device having level shift control function

Power supply apparatus having high power-factor and low distortion-factor characteristics

Discharge lamp lighting apparatus

Apparatus for operating discharge lamp