JPS6233716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a discharge lamp lighting device, and the object thereof is to provide a discharge lamp lighting device that can be used in common with mercury lamps and high-pressure sodium lamps, and that has less power fluctuations in the discharge lamp with respect to power supply voltage fluctuations. It is on offer.

FIG. 1 is a circuit diagram of a discharge lamp lighting device conventionally used for lighting a mercury lamp, in which an AC power source E is connected to an AC control element S ₁ , a current limiting inductance CH ₂ , and both ends of the AC control element S ₁ . The discharge lamp L is connected through the auxiliary current limiting inductance CH ₁ , and the reference voltage generation circuit 1 connected to both ends of the AC power supply E, the lamp voltage detection circuit 2 of the discharge lamp L, and the comparison output of the reference voltage and lamp voltage are connected. Comparison circuit 3 to obtain and PUT,
It includes a timer circuit 4 using a UJT or the like, and a lamp current detection circuit 5 that obtains the secondary side output of the current limiting inductance _CH2 .

In the above circuit, as shown in Fig. 2, the reference voltage generation circuit 1 obtains the voltage V ₂ from the power supply voltage V ₁ , and the lamp voltage detection circuit 2 obtains the DC voltage V ₃ proportional to the average value or effective value of the lamp voltage. The comparator circuit 3 compares both voltages and outputs an output voltage V ₄ when V ₃ ≧V ₂ .

On the other hand, the voltage is input to the lamp voltage/current detection circuit 5 through the current limiting inductance CH ₂ , and a DC voltage output proportional to the effective value of the lamp current is generated. The delay time T of the timer circuit 4 is determined in proportion to this output voltage.

The timer circuit 4 is delayed by a time T from the rise of the voltage V ₄ of the comparator circuit 3 and generates a trigger pulse V ₅ for the AC control element S ₁ .

In such a discharge lamp lighting device, as the lamp voltage increases after the discharge lamp starts, the rise time t of the voltage _V4 gradually advances, and from the start to stable lighting,
The lamp current is controlled to be almost constant, and the lamp current is controlled to be constant by controlling the delay time T of the timer circuit 4 using the output voltage of the lamp current detection circuit 5 during stable lighting, and the lamp current is kept constant for lighting. Since the reference voltage V ₂ also changes proportionally due to voltage fluctuations, the rising phase of voltage V ₄ also changes, and the trigger phase of voltage V ₅ also changes, causing the discharge lamp current to change due to fluctuations in the power supply voltage. There are advantages such as phase control to reduce changes, but
For example, when a mercury lamp and a high-pressure sodium lamp are used together, the ratio of the high-pressure sodium lamp to the rated power increases compared to the mercury lamp, and the high-pressure sodium lamp is more sensitive to fluctuations in power supply voltage than the mercury lamp. There are problems such as an increase in the fluctuation rate of electric power.

The reason for this is that these discharge lamps are set to consume rated power using a dedicated current-limiting inductance, and while mercury lamps are discharge lamps with constant voltage characteristics, high-pressure sodium lamps This is due to the fact that the discharge lamp has constant current characteristics.

In other words, instead of limiting the current by controlling the conduction angle during every half cycle of the lamp current, the current limiting inductance is conversely lowered and the current limiting inductance is made smaller and lighter. Even if the current-limiting inductance and control phase are determined so that the operating point can be set to the rated output in, for example, a mercury lamp, the lamp power increases in high-pressure sodium lamps due to differences in lamp characteristics. This is because the lamp voltage does not change in a mercury lamp, but changes in the lamp voltage in a high-pressure sodium lamp, and the voltage V ₃ and time t in FIG. 2 change.

In addition, when the power supply voltage fluctuates, in Figure 1, the trigger phase of the AC control element is controlled by the change in the magnitude of the reference voltage and the change in the lamp current detection output, but in the case of a mercury lamp, the lamp voltage does not change, so the The current is detected and controlled to be constant.In contrast, in high-pressure sodium lamps, if the power supply voltage fluctuates, the current does not change, but the lamp voltage changes. That is, when the power supply voltage rises, the lamp voltage also rises, the output voltage _V3 of the lamp voltage detection circuit 2 increases, the time t advances, the trigger phase advances,
Since it works to increase the output, the output fluctuation with respect to the power supply voltage increases.

As described above, the present invention is to enable a mercury lamp and a high-pressure sodium lamp, which have different characteristics, to be lit by one lighting device.

The discharge lamp lighting device of the present invention will be explained below with reference to FIGS. 3 to 5 shown as examples.
As shown in the figure, an AC power supply E includes an AC control element S ₁ , an auxiliary current limiting inductance CH ₁ , and a current limiting inductance CH ₂
A reference voltage generation circuit 1, a lamp voltage detection circuit 2, a comparison circuit 3 that compares the effective value or average value of the lamp voltage with the reference voltage, a timer circuit 4 operated by the comparison output, and a timer The discharge lamp lighting device is the same as the conventional example shown in FIG. 1 in that the circuit 4 is provided with a lamp current detection circuit 5 for controlling according to the lamp current detection output, but in addition to the lamp current detection output, the lamp voltage detection This is a discharge lamp lighting device configured such that the lamp restriking voltage detection output of the circuit 2 is input to the timer circuit 4, and the lamp current detection circuit 5 is a secondary current limiting inductance CH ₂ which serves as the main choke. The output is detected and inputted to the timer circuit 4 via a rectifying and smoothing circuit consisting of a diode D capacitor _C1 , and the lamp voltage detection circuit 2 is connected to detect the re-ignition voltage of the discharge lamp L using a transformer T. At the same time, its secondary output is input to the timer circuit 4 via the full-wave rectifier DB and the constant voltage element ZD. Resistors R ₁ , R ₂ and capacitor C ₂ are an output circuit of the lamp voltage detection circuit 2 connected between the comparison circuit 3 and the output voltage of the reference voltage generation circuit 1 for comparison. Figure 4 shows the lamp waveforms of a mercury lamp and a high-pressure sodium lamp when lit using phase control; (a)
shows a mercury lamp, and (b) shows a high-pressure sodium lamp. In this way, even if the effective value Ve of the lamp voltage is the same, in the case of a high-pressure sodium lamp, the restriking voltage is higher than that in a mercury lamp.

In addition, the power supply voltage is made higher than the rated value, and the AC control element S ₁
If the conduction angle of the AC control element S1 is widened, that is, if the lamp power is kept from increasing, the restriking voltage generally increases, and conversely, by lowering the power supply voltage, the conduction angle of the AC control element _S1 If the value is made narrower, that is, if the lamp power is kept from decreasing, the restriking voltage will decrease.

Therefore, in order to eliminate both the conventional increase in lamp output in high-pressure sodium lamps and the increase in lamp output due to increases in power supply voltage, it is necessary to detect the magnitude of the restriking portion of the lamp voltage. What is necessary is to delay the trigger phase of the AC control element _S1 in proportion to this.

In Fig. 3, the constant voltage element ZD outputs an output proportional to the voltage of the restriking portion, which exceeds the voltage corresponding to the effective value Ve of the lamp voltage in Fig. 4, to the capacitor _C1.
The voltage is smoothed and converted into direct current, which is input to the timer circuit 4 in parallel with the output of the lamp current detection circuit 5, and the timer time T shown in FIG. 2 is controlled using both voltages. Therefore, in mercury lamps, the lamp current detection output mainly controls the timer time, and in high-pressure sodium lamps, the restriking voltage is added to this and acts on the timer time. As a result, the trigger phase of the AC control element _S1 is delayed and the lamp power is reduced, so that even high-pressure sodium lamps can be lit at their rated conditions. Furthermore, with respect to fluctuations in power supply voltage, changes in the timer time increase due to changes in the restriking voltage detection output, so fluctuations in lamp power can be reduced.

FIG. 5 shows another embodiment of the present invention, in which two timer circuits 4a and 4b are provided, one timer circuit 4a performs time control according to the lamp current detection output, and the other timer circuit 4b restarts the lamp. It is controlled by voltage detection output, and can be used in common for lighting a mercury lamp and a high-pressure sodium lamp, as in the previous embodiment.

As described above, according to the present invention, a main lighting circuit including an AC control element, a current limiting inductance, and a discharge lamp connected in series to an AC power source, an auxiliary current limiting inductance connected in parallel to the AC control element, and a reference voltage generation circuit that is connected to both ends and generates a reference voltage; a lamp voltage detection circuit that outputs a DC voltage proportional to the average value or effective value of the lamp voltage of the discharge lamp; and the reference voltage and the lamp voltage detection circuit. a comparison circuit that compares the output voltage of the discharge lamp with the output voltage of the discharge lamp and outputs a voltage when the reference voltage≧output voltage; a lamp current detection circuit that outputs a DC voltage proportional to the effective value of the lamp current of the discharge lamp; In a discharge lamp lighting device comprising a timer circuit that operates and generates a trigger pulse for the AC control element after a delay time determined by the output of the lamp current detection circuit, detects the magnitude of the restriking portion of the lamp voltage, and inputs a DC output proportional to the restriking voltage to the timer circuit, and both the input and the output of the lamp current detection circuit detect the delay time. By creating a discharge lamp lighting device that is characterized by the control of This makes it convenient.

[Brief explanation of the drawing]

1 and 2 show a conventional example, FIG. 1 is a circuit block diagram of a multi-lamp lighting device, and FIG. 2 is a diagram showing voltage waveforms at various parts. 3 to 4 show embodiments of the discharge lamp device of the present invention, FIG. 3 is a circuit block diagram of one embodiment, FIG. 4 is a diagram showing restriking voltage waveforms, and FIG. 5 is a diagram showing another example. It is a figure showing an example. E... AC power supply, CH ₁ ... Auxiliary current limiting inductance, CH ₂ ... Current limiting inductance, S ₁ ... AC control element, L... Discharge lamp, 1... Reference voltage generation circuit, 2... Lamp voltage detection circuit, 3... Comparison circuit , 4... timer circuit, 5... lamp current detection circuit, D... diode,
C ₁ ...capacitor, ZD...constant voltage element, T...transformer, DB...full wave rectifier.

Claims (1)

[Claims] 1. A main lighting circuit in which an AC control element, a current limiting inductance, and a discharge lamp are connected in series to an AC power source; an auxiliary current limiting inductance connected in parallel to the AC control element; and a main lighting circuit connected to both ends of the AC power source to generate a reference voltage. A reference voltage generation circuit, a lamp voltage detection circuit that outputs a DC voltage proportional to the average value or effective value of the lamp voltage of the discharge lamp, and a comparison between the reference voltage and the output voltage of the lamp voltage detection circuit, a comparison circuit that outputs a voltage when voltage≧output voltage; a lamp current detection circuit that outputs a DC voltage proportional to the effective value of the lamp current of the discharge lamp; After a predetermined delay time, in a discharge lamp lighting device comprising a timer circuit that generates a trigger pulse for the AC control element, the re-ignition portion of the lamp voltage is controlled via a constant voltage element connected to the lamp voltage detection circuit. In addition to detecting the magnitude, a direct current output proportional to the restriking voltage is input to the timer circuit, and the delay time is controlled by both the input and the output of the lamp current detection circuit. Electric light lighting device.