Toshiba Lighting & Technology Corporation

Tsutomu Kakitani

Keiichi Shimizu

Noriyuki Kitamura

Yuji Takahashi

Fuminori Nakaya

Kenichi Inui

Masahiko Kamata

Kazutoshi Mita

Nanjou Aoike

Fumihiko Nagasaki

Kazuyuki Uratani

Keiji Takahashi

A combination-type high frequency inverter connects an isolation leakage transformer, a smoothing condenser, a resonance condenser, a first field-effect transistor and a second field-effect transistor to a diode bridge and rectifies the voltage of an AC power source in a non-smoothing rectification manner. A load circuit has a secondary winding of an isolation leakage transformer, a fluorescent lamp and a condenser. The 'on' duration of the first field-effect transistor is variable. The duration of on-duty of the second field-effect transistor is fixed. Adjusting charge voltage on the smoothing condenser changes the high frequency output voltage and the load characteristics. Load characteristics, optimal for the current mode, are given to the fluorescent lamp, in accordance with whether the flourescent lamp is in either start-up or luminance mode. Since the 'on' duration of the first-field effect transistor is variable, output compensation for fluxuation in source voltage is easily conducted.

Discharge lamp lighting device and illuminating device

The electrodes of a discharge lamp are prevented from reaching damaging temperatures which tend to occur when the discharge lamp is near the end of its useful life. The combination of a discharge lamp and luminaire contribute to ensuring the discharge lamp remains unilluminated when nearing the end of its useful life to prevent high temperature damage. Load circuit characteristics are set to provide low release voltage and high short-circuit current during full-intensity illumination, and high release voltage and low short-circuit current during dimmed operation. The discharge lamp operating in a dimmed mode at the end of its useful life is switched to full-intensity illumination mode to ensure the discharge lamp becomes unilluminated. This configuration prevents high temperatures at the electrodes from damaging the glass bulb, base, socket and other components of the discharge lamp and luminaire.

Discharge lamp lighting device and illumination device

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

Power supply apparatus having high power-factor and low

A power supply apparatus has a rectifier for outputting a non-smoothed DC. A switching circuit alternately shut off output of the rectifier at a high frequency, which includes first and second switches. A first capacitor couples to the first and second switches for smoothing output of the rectifier. A series resonance circuit includes a second capacitor and an inductor so that the voltage across the first capacitor becomes lower by the resonance voltage than that of the output of the rectifier. The switches are coupled to a feedback circuit including a saturatable current transformer having a primary winding and secondary winding. A control means varies the saturation time of the saturatable current transformer.

Power supply

An apparatus for operating discharge lamp. The apparatus includes a source of electrical power, switching devices for switching the electrical power, a control circuit for controlling the switching devices, a transformer having a primary winding for receiving the electrical power switched by the switching devices and a secondary winding for supplying power to the lighting apparatus, a resonant circuit including an inductor and a capacitor for regulating the frequency of the electrical power and a circuit for powering the control circuit, the powering circuit including a secondary winding on the inductor and an additional winding on the transformer connected in a differential manner.

Power source for lighting apparatus

Apparatus for operating discharge lamp

In a discharge lamp lighting apparatus of this invention, an AC voltage of a commercial AC power source is full-wave-rectified by a rectifier, and this full-wave-rectified AC is smoothed by a smoothing circuit connected to the rectifier. An inverter operated by a series resonance circuit constituted by a resonant choke coil and a capacitor is connected to the rectifier, and field-effect transistors are connected to this series resonance circuit. By the operation of the inverter, a high-frequency AC is induced in a output winding of a boosting transformer having an input winding connected in parallel with the capacitor of the series resonance circuit. The output winding then supplies the induced AC to discharge lamps for lighting the discharge lamps.

Discharge lamp lighting apparatus

A discharge lamp lighting device includes a pair of main switching transistors and a feedback transformer. Each of the main switching transistors 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 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. A first control circuit is connected to each of the bases of the main switching transistors and includes a variable impedance element to control the oscillating frequency by varying the impedance of this variable impedance element. A second control circuit 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 so that the on-off operation of each of the paired main switching transistors can be controlled.

Discharge lamp lighting device having level shift control function

A fluorescent lamp lighting apparatus comprising a DC power source, a pair of field-effect transistors which are connected in series to each other, in which drains and sources of these transistors are connected in series to each other, whereas gates are connected to an oscillator, a pair of voltage-dividing capacitors which are connected in parallel to the DC power source, and an inverter circuit having an insulative leakage transformer whose primary coil is connected to a contact between these field-effect transistors and also to the other contact between those capacitors. One-end of filaments of a fluorescent lamp are connected to both ends of the secondary coil of the leakage transformer, whereas a startup capacitor is connected between the other ends of the filaments. By provision of a series resonant circuit composed of the secondary coil and the startup capacitor, part of the series resonant circuit is released while the fluorescent lamp is off from the lighting apparatus, thus minimizing the resonant output.

Fluorescent lamp lighting apparatus

The invention circuit for a discharge lamp comprising a first switching circuit, a series resonant circuit, and a current transformer. The series resonant circuit energizes the discharge lamp by means of resonant output corresponding to the output from the first switching circuit. The current transformer incorporates the first, second, and the third windings. When the first winding inserted in the series resonant circuit is driven, the first winding outputs a predetermined amount of current to the second and third windings. The inverter circuit further comprises a second switching circuit, a pair of time constant circuits, and a control circuit. The second switching circuit controls ON-OFF operation of the first switching circuit in response to the output from the second winding. A pair of time constant circuits respectively contains the predetermined time constant values, and based on the predetermined time constant, each of the time constant circuits controls the switching timing of the second switching circuit. The control circuit controls the time constant of these time constant circuits in response to the output from the third winding of the current transformer.

Inverter circuit for stable illumination of discharge lamp

A discharge lamp lighting apparatus according to this invention includes an inverter circuit for supplying a high frequency power source to a discharge lamp having one of different ratings, a voltage detecting coil of an inverter transformer for detecting a load voltage applied from the inverter circuit to the discharge lamp, a current transformer for detecting a load current supplied from the inverter circuit to the discharge lamp, and a control section and an oscillation circuit for controlling the power source supplying operation of the inverter circuit based on detection outputs of the voltage detection coil and current transformer. The control section and oscillation circuit sequentially raise an output of the inverter circuit at the starting time of the discharge lamp, identifies the type of the discharge lamp according to the starting voltage at the lighting time of the discharge lamp, and controls the starting voltage and current of the discharge lamp according to the type of the discharge lamp thus identified.

Growing community of inventors

Yokohama, Japan

Tsutomu Kakitani