JPH02181396A - Discharge lamp lighting device and illumination apparatus using it - Google Patents

Abstract

PURPOSE:To reduce the switching loss, to decrease the number of parts, and to realize a compact size and a low cost, by deciding the on-timing of a switching device responding to the detected voltage of the second inductor which is the current limit impedance of a discharge lamp. CONSTITUTION:The second inductor 5 which determines the current limit impedance of a discharge lamp 4 is connected between one end of a secondary winding 23 and one end of the discharge lamp 4. A capacitor 6 for starting of the discharge lamp 4 is to be constant-set to resonate with the second inductor 5 and the like in the preheating if a filament prior to the starting of the discharge lamp 4. And a switching control device 8 to ON/OFF-control the detecting device to detect the voltage of the second inductor 5, such as a detecting winding 7 and a switching device 1, is provided. Consequently, the switching loss can be reduced, and the number of parts is reduced to realize a compact size and a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a discharge lamp lighting device that energizes a discharge lamp with a high frequency voltage, and a lighting device using this discharge lamp lighting device.

(Prior Art) Conventionally, various methods have been proposed for lighting a discharge lamp at high frequency using an inverter or the like. Among these, there is one that uses a so-called single-mode inverter of the bias excitation type, which mainly consists of one transistor and a parallel resonant circuit connected in series with the transistor.

This system has the advantage of being relatively simple in configuration and relatively easy to control the output of the inverter, but if the on-timing of the switching device is not performed properly, switching loss will disappear and the switching device will This causes problems such as abnormal heat generation and destruction.

For this reason, in the past, the voltage across the switching device was detected, and the ON control signal was not output during the period when this voltage was occurring, and the reset current flowing in the switching device in the forward and reverse directions was detected. A device has been proposed in which an ON control signal is output.

(Problems to be Solved by the Invention) However, all of the above-mentioned conventional devices require special detection means, which inevitably increases the number of parts and increases the cost. In addition, the conventional technology uses the above-mentioned detection means only to prevent switching losses from increasing, so for example, the inverter's output is determined at each stage, such as immediately after starting the discharge lamp, during filament preheating, and during lighting. In order to control the output power, a separate output control means was required.

The present invention was made to solve the above-mentioned conventional problems, and is based on the idea of simplifying the detection means by using the second inductor as the current-limiting impedance of the discharge lamp. By determining the on-timing of the switching device according to the detection signal detected from the second inductor, switching loss can be extremely reduced, and the on-period of the switching device can be controlled to control the output of the inverter. The first object of the present invention is to provide a discharge lamp lighting device that can perform the following operations.

A second object of the present invention is to provide a lighting device equipped with a discharge lamp lighting device that has extremely low switching loss and allows easy control of light output.

[Structure of the invention]

(Means for Solving the Problem) The invention set forth in claim 1 (hereinafter referred to as the first invention) is a DC power source comprising a switching device, a parallel circuit of a first inductor, and a capacitor. A resonant circuit provided in series with the switching device between both terminals, a discharge lamp provided in parallel with this resonant circuit, and a discharge lamp interposed between the discharge lamp and the resonant circuit. A second inductor as a current-limiting impedance, a detection means for detecting the voltage of the second inductor, and a polarity reversal of the resonant voltage when the switching device is in an off period in the detected voltage from the detection means. an on control means that determines the on timing of the switching device according to the switching device, an off control means that can adjust the on period of the switching device, and an on and off control signal to the switching device under the control of the on control means and the off control means. The configuration is characterized in that it includes a switching control device having a driving means for outputting an output.

The invention set forth in claim 2 (hereinafter referred to as the second invention) comprises a lighting fixture body and the discharge lamp lighting device of the first invention provided in the lighting fixture body. This is a structural feature.

The main body of the lighting equipment may be of a direct-ceiling type, a recessed type, a hanging type, or a tabletop type.

(Function) The first invention determines the on-timing of the switching device in response to polarity reversal of the resonant voltage when the switching device is in the off period during the detection voltage, so that the on-timing of the switching device is determined when the voltage across the switching device disappears or It is possible to reliably supply the ON control signal in the vicinity thereof, and therefore the switching loss can be extremely reduced. Furthermore, since the on-time of the switching device can be adjusted, the output of the inverter can be easily controlled.

Furthermore, the second inductor, which is the current limiting impedance of the discharge lamp, is used to detect the switching control signal, thereby reducing the number of parts and making it possible to reduce the size and price.

A second invention can provide a lighting device having the effect of the first invention.

(Example) Hereinafter, an example of the first invention will be described with reference to FIG. 1 is a switching device. In this embodiment, a bipolar type transistor is used, but a MOS type field effect transistor or the like may be used. 2
is a resonant circuit consisting of a parallel circuit of a first inductor 21 and a capacitor 22, and is connected in series with the switching device 1 and provided between both terminals of the DC power supply 3. The first inductor 21 is, for example, a primary winding of a single-turn transformer. Reference numeral 4 denotes a discharge lamp, such as a fluorescent lamp, which is provided in parallel with the resonant circuit 2. That is, in this embodiment, it is provided between one end of the first inductor 21 and one end of the secondary winding 23 of the single-turn transformer. A second inductor 5 is a current-limiting impedance of the discharge lamp 4, and is connected between one end of the secondary winding 23 and one end of the electric lamp 4. Reference numeral 6 denotes a capacitor for starting the discharge lamp 4, and a constant can be set so as to resonate with the second inductor 5 and the like during preheating of the filament before the discharge lamp 4 is started. Reference numeral 7 denotes a detection means for detecting the voltage of the second inductor 5, such as a detection winding. Reference numeral 8 denotes a switching control device that controls on/off of the switching device 1. This switching control device 8 includes a rectifier 81 that half-wave rectifies the detected voltage from the detection means 7.
, an on control means 82 that determines the on timing of the switching device 1 based on the output of the rectifier 81, an off control means 83 that can adjust the on period of the switching device 1, the on control means 82 and the off control means 8.
3 and outputs an on/off control signal to the switching device 1. The on control means 82 includes a first integration circuit 821
and a comparator 822 that compares the output of the integration circuit 821 with a reference value and outputs a signal when the output of the integration circuit 821 reaches a predetermined value with respect to the reference value. The off control means 83 includes a second integrating circuit 831 and a comparator that compares the output of this integrating circuit 831 with a reference value and outputs a signal when the output of the integrating circuit 831 becomes a predetermined value with respect to the reference value. It consists of 832. Here, the off control means 83 controls the integration circuit 83 so that the signal output is slower than the on control means 82.
A time constant or reference value of 1 is set. Further, the off control means 83 controls the signal output from the comparator 832 by making the reference value, the constant of the integrating circuit 831, etc. variable, or by making the voltage supplied to the integrating circuit 831 variable. The period until can be adjusted. The driving means 84 is, for example, a flip-flop, and the comparator 821 of the on-control means 82 is connected to the set terminal.
The signal from the comparator 831 of the OFF control means 83 is inputted to the reset terminal, respectively, and the output is supplied to the control pole of the switching device 1.

Next, the operation of this embodiment will be explained with reference to FIG. 2(a) shows the detected voltage waveform of the detection means 7, FIG. 2(b) shows the voltage between the collector and emitter of the switching device 1, and FIG. 2(c) shows the second integrating circuit 831 of the off control means 83. The figure (d) shows the collector current waveform of the switching device 1. When the detected voltage from the detection means 7 is input to the switching control device 8, the rectifier 81 allows only the voltage on the positive electrode side to flow in FIG. 2(a). Therefore, the integration circuit of the ON control means 82 is
1, when the switching device 1 is supplied with an output from the rectifier 81 due to polarity reversal of the resonant voltage during the off period, the comparator 822 outputs a signal because it reaches a predetermined value with respect to the reference value after an integration time constant. do. The driving means 84 is set by the signal from the comparator 822 and outputs an on control signal to turn on the switching device 1. Therefore, the integration time of the first integration circuit 821 is determined as shown in FIG. 2(a).
) and (b), the switching loss can be reduced by setting the time to match or approximate the time from when the resonant voltage changes polarity until the collector-emitter voltage of the switching device 1 disappears. can be made extremely small. When a predetermined time has elapsed after the switching device 1 is turned on, the output of the second integrating circuit 831 in the off control means 83 reaches a predetermined value with respect to the reference value, and the comparator 832 outputs a signal. The drive means 84 is reset by this signal and stops supplying the ON control signal to the switching device 1. That is, the switching device 1 is turned off by outputting an off control signal. Therefore, the resonant circuit 2 resonates based on the energy stored during the on period. Thereafter, the operations explained above are repeated.

〔Effect of the invention〕

As described above, the first invention determines the turn-on timing of the switching device according to the detected voltage of the second inductor, which is the current-limiting impedance of the discharge lamp. Since the time can be adjusted, the output can be easily controlled. Moreover, since voltage is detected using current-limiting impedance, the number of components is small and
This allows for smaller size and lower cost.

The second invention can provide a lighting device that provides the same effects as the first invention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the first invention, and FIG. 2 is a voltage or current waveform diagram of each part for explaining the operation of the embodiment. 1... Switching device, 2... Resonant circuit, 5...
- Second inductor, 7... detection means, 8... switching control device.

Claims (2)

[Claims] (1) A switching device; A resonant circuit consisting of a parallel circuit of a first inductor and a capacitor and provided in series with the switching device between the output terminals of the DC power supply; ■ of the above-mentioned discharge lamp inserted between the electric lamp and the above-mentioned resonant circuit;
a second inductance as a current impedance; a detection means for detecting the voltage of the second inductor; and a detection means for detecting the voltage of the second inductor; ON control means for determining the ON timing of the switching device;
a switching control device comprising: an off control means capable of adjusting the on time of the switching device; and a drive means controlled by the on control means and the off control means to output on and off control signals to the switching device; A discharge lamp lighting device characterized by: (2) A lighting device comprising: a lighting device main body; and the discharge lamp lighting device according to claim (1) provided on the lighting device main body.