JPS58170376A - Power source - Google Patents

Abstract

PURPOSE:To inexpensively construct the structure of a power source by operating a condenser provided not to form a no-current zone of a load such as a lamp as a surge voltage absorber. CONSTITUTION:Transistors 7, 8 alternately receive negative and positive biases via induced voltage of a coil 43, while high frequency voltage is induced at the secondary coil 42 of a transformer 4 by the resonance of the primary coil 41 and a condenser 5, thereby firing a discharge lamp 15. A condenser 16 is provided not to produce a no-current zone of the lamp 15. When surge voltage is introduced from the power source side, a thyristor 21 is conducted through a Zener diode 24. A surge voltage which is introduced from the power source side by the conduction of the thyristor 21 is absorbed by the condenser 16.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inverter circuit for converting a rectified voltage obtained by rectifying a low frequency alternating current voltage into a high frequency current voltage, and a A series circuit of a capacitor and a diode having a polarity opposite to the voltage tIf is connected between the input terminals of the circuit, and the capacitor is connected to an inverter circuit in an area where the input voltage of the inverter circuit is relatively high. A power supply device comprising a charging circuit that charges to the same polarity as the rectified voltage when viewed from the circuit side, and supplies power from the capacitor to the inverter circuit in an area where the input voltage of the inverter circuit is relatively low. It is.

This 1@ power supply device is used for high-quality discharge lamp lighting devices, etc., because it can improve the lighting characteristics by eliminating the no-current section of the discharge lamp, for example. A commercial power source is generally used as the low frequency AC voltage. In the case of commercial electric power, as well as in the case of privately generated power sources, surge pressure is generated due to various reasons, and this surge also flows into discharge lamp lighting equipment, etc., and it is particularly important for components that are sensitive to high voltage, such as semiconductor devices. may lead to destruction.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply device having a surge voltage absorbing means that can be constructed at a particularly low cost by skillfully utilizing the above-mentioned circuit configuration features.

In order to achieve this object, the present invention is characterized in that a switching element is connected in antiparallel to the front diode, which conducts in response to a surge voltage contained in the rectified voltage and invading the rectified voltage. Furthermore, in order to achieve the above object, the present invention is characterized in that a voltage non-linear element is connected in parallel to the capacitor together with the switch element.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

The figure shows an example in which the present invention is applied to a discharge lamp lighting device. The basic main circuit of this device is to rectify an AC voltage obtained from a low-frequency AC power source, for example, a commercial power source, and then rectify the pulsating DC current obtained by rectifying it with a rectifier 2; It consists of a circuit that converts it into a multi-frequency AC voltage of about 50 KH2 and supplies it to the -C radiation lamp 15. The inverter circuit 3 includes a primary winding 4 having a center tap connected to one output terminal of the rectifier 2.
1. A transformer 4 having a secondary winding 42 and a self-excited photography control winding 43, a resonance capacitor 5 connected in parallel to the negative winding 41, and a resonant capacitor 5 connected in series to the other output terminal of the rectifier 2. A transistor 7 . connected to or connected to the axle 6 , and a transistor 7 . connected between the other end of the reactor 6 and both winding ends of the primary winding 41 .
8. Both transistors 7 and 8 have rectifier @2
from one output terminal of the common resistor 9 and diode 1
0, and between the base terminals of each transistor through resistors 11 and 12.

The transformer winding 43 is connected to the series reactor 13 for on/off control of the transistor 7.8, that is, for oscillation control.
and via a shunt resistor 14 between the base terminals of both transistors 7.8. The above-mentioned parts 4 to (3) 14 constitute a self-supporting loss type circuit 3.

In the illustrated circuit, in order to eliminate the no-drag section of the discharge lamp 15, the output loss of the input/output circuit @ 3 that occurs in the section where the instantaneous value of the pulsating DC output of the rectifier 2 is small is eliminated. A capacitor 16 that supplies energy to the circuit 3 in the section is connected between both output terminals of the rectifier 2 with a diode 17 arranged with a polarity opposite to the output DC of the rectifier 2 and a direct current IJ. has been done. The capacitor 16 is connected to the output of the rectifier 2 from the center tap of the transformer 4 and the auxiliary taps appropriately set on both sides of the transformer 4 in the section where the instantaneous value of the output voltage of the rectifier 2 is large. It is charged with the same polarity as the voltage,
When the instantaneous value of the output voltage of rectifier 2 decreases, the transformer -
Next winding 41, transistor 7 or 8, reactor 6
, and the diode 17, and this discharge prevents the above-mentioned no-current section from occurring.

The configuration up to this point has already been proposed (4), and is turned on based on the base current supplied via resistor 9, diode IO and resistor 11. Both transistors controlled 7.8
receives negative bias and positive bias alternately due to the induced voltage in the winding 43, and on the other hand, due to the synergistic action of the primary winding 41 and the capacitor 5, the transformer 4 is excited at high frequency, and the secondary winding 42 receives high frequency The discharge lamp 15 is turned on by inducing a voltage. Note that when the power is first turned on, one of the transistors 1 and 8 turns on first due to a slight difference in characteristics between them. The function of the capacitor 16 is as described above.

A feature of the present invention is that a switching element, for example, a thyristor 21 is connected in antiparallel to the diode 17, and the thyristor 21
1 is that it is made conductive by surge voltage entering from the power supply side. For conduction control, resistors 22 and 23 are connected in series between the output terminals of the rectifier 2, and a Zener diode is connected between the connection point of both resistors and the gate of the thyristor 21.

When a surge voltage enters from the installation side, the divided phase voltage of the resistor 23 also rises, so the Zener diode 24
The thyristor 21 is made conductive through it. Due to the conduction of the thyristor 21, the surge voltage that enters from the power supply side is absorbed by the capacitor 16, and it is possible to prevent the destruction of electronic components, such as transistors, included in the device. By using the capacitor 16,
For example, it can absorb surge voltages with sieve energy that cannot be absorbed by voltage non-linear resistance elements, and it can still effectively absorb surge voltages with a wide range of, for example, 1 m5 (mi IJ seconds). can do.

The illustrated device also includes a voltage non-linear element 25 in parallel with the capacitor 16. By doing this, narrow steep mountain tributaries can be mainly absorbed by the capacitor 16, and wide power surges can be mainly absorbed by the voltage nonlinear element 25, and both wide and narrow surge voltages can be absorbed well. This makes it even more effective.

In the practical example described above, it has been explained that power is supplied to the discharge lamp 15 from the pulsating oscillation type inverter circuit 3, but the present invention is not limited thereto.

The inverter circuit can be replaced with other known ones as appropriate, and the present invention is suitable for loads other than open lamps in which the supply voltage and current do not have any dead sections. It can be applied to

Furthermore, regarding the charging energy of the capacitor 16,
In the above implementation-〇, it is taken from the transformer winding included in the inverter circuit 3, but it is not necessarily necessary. For example, the transformer, rectifier, and charging impedance are taken from the input side' power supply of the rectifier I'i1i, the transformer 2. You may also take it through.

As stated above ((According to the present invention, since the capacitor provided so as not to create a no-current section in a load such as a discharge lamp can also be used as a surge voltage absorber, it is equipped with a surge voltage absorbing means. A power supply device can be constructed at low cost.Furthermore, by adding a voltage non-linear element, surge voltages both wide and narrow can be effectively absorbed.

(7)

[Brief explanation of drawings]

The prisoner is equipped with ``ton training +t, -j according to the present invention! This is a connection diagram showing an example of a row. 2... Brazer, 3... Inverter circuit, 16...
Capacitor, 17.19.20...I° Iode, 2
1...Thyristor, 22.23...Resistor, Sae...
Zener diode, 25... Voltage nonlinear element. Applicant's representative Inomata 1., ¥(8)

Claims (1)

[Claims] 1. An inverter circuit that converts a rectified voltage obtained by rectifying a low-frequency AC voltage into a high-frequency AC voltage, and a capacitor connected between an input terminal of the inverter circuit and the rectified voltage. and a charging circuit that charges the capacitor to the same polarity as the rectified voltage when viewed from the inverter circuit side in an area where the input voltage of the inverter circuit is relatively high. , in a power supply device in which the inverter circuit is supplied from the capacitor in an area where the input voltage of the inverter circuit is relatively low, a surge voltage included in the rectified voltage is connected antiparallel to the diode. A power supply device characterized by directly reading a switching element that conducts in response. 2. The power supply device according to claim 1, characterized in that a voltage non-direction element is connected in parallel with the capacitor.