JPS61190895A - discharge lamp lighting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an improvement in a discharge lamp lighting device using a high frequency inverter circuit, and in particular to a drive signal for a DC-DC converter as an input source of the high frequency inverter circuit. The present invention relates to a discharge lamp lighting device that converts the waveform of a signal to reduce switching loss and noise.

[Prior art and its highlights]

FIG. 3 shows an example of a discharge lamp lighting device using a conventionally used high frequency inverter circuit.

1 is an AC power supply, 2 is a full-wave rectifier that converts AC to DC,
3 is a DC-DC converter that smoothes the full-wave rectified output, and 4 is a two-stone sine wave inverter that oscillates at 20 to 50 KHz to convert DC voltage into high-frequency voltage.

5 is a load, such as a fluorescent lamp, which is lit by being supplied with high frequency power, and 6 is a leakage transformer. To explain the operation of this device, first, when an AC power source 1 is supplied, it is rectified by a full-wave rectifier 2 to become a pulsating W current voltage and is supplied to an inverter 4. As a result, the switching transistors 42 and 43 are connected through the resistor 41 of the inverter 4.
However, due to variations in the DC NH amplification factor bFE of each transistor, one of the transistors turns on first, causing vibration due to the inductance of the leakage transformer 6 and the resonant frequency of the capacitor 44. An oscillating voltage is induced in each winding of the leakage transformer, and the switching operation continues. One of the voltages induced in the control winding 63 of the leakage transformer 60 is DC-D.
It is supplied to the base of the transistor 31 of the C converter 3. Now, while the pulsating current voltage that is the output of the full-wave rectifier 2 is lower than the peak voltage, the capacitor 32, inductor 33, and transistor 31 are all connected, and a charging current flows through the capacitor 32.
T-train. The pulsating voltage has passed the peak point and capacitor 3
Naruto capacitor 32, inverter 4 below the charging voltage of 2
Since power is supplied to the inverter 4 through the loop of diodes 34, the DC voltage supplied to the inverter 4 does not fall below a certain voltage.

This has the following benefits! :, Bring on wo.

(2) Since the voltage supplied to the discharge lamp 5 does not drop below a certain voltage, the lamp is turned on and off repeatedly every half cycle of the weight, which improves the luminous efficiency.

■ Since the charging capacitor 32 is charged using a high-frequency signal that is the unique vibration of the inverter, the charging current is divided and charged, and as a result, the input power is high and the wiring capacity tv
Can be reduced.

By the way, the voltage applied to the DC-DC converter 3 is as shown in FIG. 4(a). Furthermore, since the voltage induced in the control winding 63 is as shown in FIG. 4(b), the signal applied to the base of the transistor 31 of the DC-DC converter 3 is a half-wave signal rectified by the diode 35. Therefore, every other unique oscillation wave (high frequency voltage) applied to the transistor 31 turns on.

However, if the base signal of the switching transistor 310 is a sine wave, the collector current may not turn off immediately even when the base signal is turned off. This is because it is proportional to the amount of charge, and if you try to turn on the transistor as close to the zero cross as possible, the base current will become excessive near the peak of the sine wave, so even after the base current disappears, the collector current will not disappear. It is.

This not only increases the switching loss of the transistor, but also causes failure of the transistor and generation of noise since switching is performed in the high applied voltage range.

[Purpose of the invention]

Therefore, in order to eliminate the above-mentioned drawbacks, the present invention adds a circuit that shapes the base signal, which is a sine wave, into a rectangular wave with steep rises and falls, thereby reducing the loss of the switching transistor and reducing noise. This is an attempt to suppress the outbreak.

[Structure and operation of the invention]

-One specific example of the present invention is shown in FIG. In the same figure, 1
is an AC t@, 2 is a full-wave rectifier, 3 is a DC-DC converter, 4 is a sine wave inverter, 5 is a load, and 6 is a leakage transformer. The difference from FIG. 3 is that an auxiliary transistor 31 for forming a rectangular wave is provided in the base signal circuit of the transistor 31 of the DC-DC converter 3, and that the collector terminal and the transistor 31 of the DC-DC converter 3 are connected to each other.
1 is connected between the bases of 1 through a circuit in which a resistor 35 and a capacitor 36't are connected in parallel.

When connected in this way, the voltage waveforms at each part will be as shown in FIG.

That is, the high frequency voltage (second
-(a) ) is rectified by a diode 46 and supplied to the base of an auxiliary transistor 45 . Due to the switching operation of the transistor 45, a rectangular wave signal is obtained for the collector pressure. In this case, a small signal transistor can be used, and since the collector current of the transistor is small, there is little charge accumulation in the base and collector. Therefore, a rectangular wave relatively close to high frequency No. 48 is obtained (FIG. 2(b)).

When this signal passes through a parallel circuit consisting of a capacitor 36 and a resistor 35, a rectangular wave with a steep rise and fall is obtained as shown in FIG. , it is possible to reduce switching loss of the transistor and reduce noise.

〔Effect of the invention〕

As described above, by changing the DC-DCC converter drive signal from a sine wave to a rectangular wave, switching loss is reduced and noise is effectively reduced, and a highly efficient lighting device can be provided.

Although the description has been made so far of a book in which a signal obtained from controlled winding of an inverter is used as a drive signal for a DC-DC converter, the present invention is not limited to this. In short, the fourth [/(a)
In order to reduce loss and reduce noise with a waveform like the one shown in , the drive signal should be synchronized with the applied snow and pressure and turn on near the nine-zero cross.

A square wave with a steep rise and fall using QFF is good, and if that condition is met, you can add your own oscillation circuit without using your own high-frequency signal and obtain the same function as a full drive source.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a discharge lamp lighting device according to the present invention, Fig. 2 is a voltage waveform diagram of each part of the device, Fig. 3 is a circuit diagram of a conventional discharge lamp lighting device of the same type, and Fig. 4 is a circuit diagram of the same type of discharge lamp lighting device. It is a voltage waveform diagram of each part. In Figure 1, 1...AC power supply, 2...full wave rectifier circuit, 3...D
C-DC converter, 4...high frequency inverter circuit,
5...Load, 6...Leakage transformer. -Q CJ

Claims (2)

[Claims] (1) An AC power source, a full-wave rectifier that rectifies the AC power source, a constant current inverter that is composed of at least an inductor, a transistor, and an oscillation transformer and converts the output of the full-wave rectifier into a high-frequency voltage, and the constant current inverter A discharge lamp to be energized, and a DC-DC having a charging/discharging path on the output side of the inductor and a discharge path on the output side of the full-wave rectifier.
A discharge lamp lighting device comprising a converter, characterized in that a rectangular wave is used as a drive signal for the DC-DC converter. (2) The DC-DC converter is characterized in that it is driven by supplying the output of a waveform shaping circuit that converts the output of the control winding of the oscillation transformer into a rectangular wave via a circuit connected in parallel with a capacitor and a resistor. A discharge lamp lighting device according to claim 1.