JPS5983580A - Power source - Google Patents

Abstract

PURPOSE:To eliminate the unstability of the operation at the no load time and to prevent a noise from occurring by connecting a resistor of relatively high resistance in parallel with a capacitor of a voltage divider. CONSTITUTION:A power source has a power source circuit 1, a constant current reactor 2, a transistor inverter 3, a starting delay circuit 6 and a voltage divider, and electric power is supplied to a load 4. A resistor 505 is connected in parallel with the first capacitor 501 of the voltage divider. When the load 4 is removed so as to become no load state, a base bias is supplied suitably through resistors 505, 503 even if the smoothing action by capacitors 501, 502 increases. Accordingly, the energization of transistors 301, 302 can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device using a transistor inverter.

In a conventional transistor inverter type power supply device that directly rectifies a commercial AC power source and uses it as a power source, the power source that energizes the collector of the transistor that makes up the transistor inverter passes through a high-resistance resistor &f to the base of the transistor. In this case, in order to flow a predetermined base current, the current amplification factor hfe of the transistor must be
Since it is necessary to flow a relatively large current determined by the resistor through the resistor, there is a drawback that the loss in the resistor becomes large. Therefore, the present inventor first published a power supply device shown in FIG. 1 (Japanese Patent Application No. 123025/1982). In the figure, 1 is a power supply circuit consisting of a commercial AC power supply 101 and a full-wave rectifier circuit 102, 2 is a constant current reactor, 3 is a transistor inverter, 4 is a load such as a discharge lamp, and 5 is a voltage dividing circuit. Inno Kuichiyo 3 has transistors 301 and 302 and capacitor 3
03, resistors 304 and 305, and an oscillation transformer 306 having a primary winding 3a, a feedback winding 3b, and a secondary winding 3C. ″2nddensa 50
1 and 502, a resistor 503, and a diode 504. When this inverter type power supply device is powered on, a DC voltage is applied between the collector and emitter of the transistors 301 and 302, and the heavy pressure obtained across the second capacitor 502 passes through the resistors 304 and 305 to the transistors 301 and 3020. Applied between two emitters. As a result, the inverter 3 oscillates, transistors 301 and 302 become conductive alternately, and the oscillation transformer 306
A high frequency voltage is induced in the secondary winding 3C. This high frequency′
The load 4 is driven by the voltage. Here, the resistors 304 and 305 are for preventing a short circuit between the bases of the transistors 301 and 302, and may have sufficiently low resistance values, so that the power loss in these resistors is extremely small.

In the circuit shown in FIG. 1 above, the capacitor 502
The capacity of C! is set considerably larger than the capacitance CI of the capacitor 501. For example, when the load 4 is a 110W fluorescent lamp, if the constants of each component are set to appropriate values, the capacitance of the capacitor 501 is several μF, and the capacitance of the capacitor 502 is 10 to several tens of μF. Therefore, load 4
When the collector currents of the transistors 301 and 302 become small, such as when the transistors are removed and the transistors are left in a no-load state, the smoothing force of the capacitors 501 and 502 is large, and the output of the full-wave rectifier becomes a direct current with less pulsating current. As a result, no output can be obtained from the voltage dividing circuit formed by the capacitors 501 and 502, and the energization of the transistors 301 and 3020 bases becomes unstable, causing an intermittent portion to appear in the secondary voltage of the oscillation transformer 306.

In such a state, high-frequency noise power 1 is generated, which may interfere with radio and television reception.

In addition, in the circuit shown in Figure 1, the power supply frequency is 50Hz and 60Hz.
It has been difficult to obtain a power supply unit that can be used in both cases. That is, when the time constant of the charging/discharging circuit of capacitors 501 and 502 is constant, the voltage appearing across the capacitor 502 varies depending on the power supply frequency9, and the frequency is 50H.
The voltage appearing across the capacitor 502 in case 2 is
The voltage that appears when the frequency is 60 Hz is lower than the voltage that appears when the frequency is 60 Hz, so if the constants of each part are set so that it operates satisfactorily when the frequency is 60 Hz, when the minimum value of the pulsating voltage approaches zero when the frequency is 50 Hz, transistor 301.30
2 becomes insufficiently energized, making it impossible to supply sufficient power to the load 4. Conversely, if each constant is set to an appropriate value in the case of 5011z, in the case of 60)tz, the base activation of transistors 301 and 302 becomes excessive at the rise of the pulsating voltage waveform, resulting in increased loss in these transistors and a change in the output waveform. This results in problems such as an increase in noise due to the instability of the rise of the signal.

An object of the present invention is to provide a power supply device that prevents base energization of a transistor inverter from becoming unstable when a no-load state occurs.

Another object of the present invention is to provide a power supply device that can be used in common for power supplies with different frequencies.

A first invention of the present application includes a full-wave rectifier circuit connected to an AC power supply, a first capacitor having one end coupled to the positive output terminal of the full-wave rectifier circuit, and one end coupled to the other end of the first capacitor. a voltage divider circuit having a second capacitor coupled to the negative output terminal of the full-wave rectifier circuit;
A transistor inverter whose base is energized and operated by the voltage across the second capacitor of the voltage dividing circuit is also provided.
A smoothing circuit is connected in parallel to the capacitor.

The present invention will be described in detail below along with its embodiments. Figure 2 shows an embodiment of the first invention of the present application, in which 1 is a commercial power supply 101 and a full-wave rectifier that rectifies the output of this power supply. This is a power supply circuit consisting of a circuit 102. A constant current reactor 2 is connected to the positive output terminal A of the full-wave rectifier circuit 102.
One end of the reactor 2 is connected, and the other end of the reactor 2 is connected to the intermediate tap of the primary winding 3a of the oscillation transformer 306.

The collectors of transistors 301 and 302 whose emitters are commonly connected are connected to one end and the other end of the primary winding 3& of an oscillation transformer 306, respectively, and a capacitor 303 is connected in parallel between the collectors of both transistors. One end and the other end of the feedback winding 3b of the oscillation transformer 306 are connected to the bases of the transistors 301 and 302, respectively, and one ends of the resistors 304 and 305 are connected to the bases of the transistors 301 and 302, respectively.
The other ends of resistors 304 and 305 are commonly connected.

Transistors 301 and 302, a capacitor 303, resistors 304 and 305, an oscillation transformer 306, and a transistor inverter 3 are configured. One end t11 tap of the secondary winding 3c of the oscillation transformer 306 F + t3
, and the other end t4, terminals are drawn out from the secondary winding between one end t1 and the tap top 2, and between the tap t3 and the other end t.
Filament of fluorescent lamp as load 4 between 4)
ft and f2 are connected.

One end of a first capacitor 501 is also connected to the positive output terminal A of the full-wave rectifier circuit 102.1. first capacitor 5
One end of a second capacitor 502 is coupled to the other end of 01 through a resistor 503. second capacitor 50
The other end of 2 is connected to the negative output terminal B of the full-wave rectifier circuit 102, and the anodes of the series circuit of the resistor 503 and the second capacitor 502 are connected to the negative output terminal side of the full-wave rectifier circuit 102. diodes 504 are connected in parallel.

A resistor 505 with a relatively high resistance value is connected in parallel to both ends of the first capacitor 501, and a Zener diode whose anode is directed toward the negative output terminal side of the full-wave rectifier circuit 102 is connected to both ends of the second capacitor 502. 506 are connected in parallel. A voltage dividing circuit is constituted by first and second capacitors 501 and 502, resistors 503 and 505, a diode 504, and a Zener diode 506, and the transistor inverter 3 is connected across the second capacitor 5020.
The anode of the thyristor 601 is connected to the connection point C between the capacitor 502 and the resistor 503 of 27% 2, and The cand is connected to the common junction of resistors 304 and 305 which lead to the leads of transistors 301 and 302.

A series circuit of relatively high resistance resistors 602 and 603 and a relatively low resistance resistor 604 are connected in parallel between the anode candes of the thyristor 601.
The gate of the thyristor 601 is connected to the connection point of and 603. A capacitor 605 is connected in parallel between the gate candes of the thyristor 601, and each part of the thyristor 601 to the capacitor 605 constitutes a starting delay circuit 6.

In the device shown in FIG. 2, when the power supply 101 is turned on, a voltage is applied across the reactor 2 and the primary winding 3a of the transformer 306 between the collectors and emitters of the transistors 301 and 302, and at the same time the second capacitor The voltage across 502 is the same as the series circuit of resistors 602 and 603, the parallel circuit of resistor 604, resistors 301 and 302, and f:
is applied between the pace emitters of transistors 301 and 302 through. At this time, transistors 301 and 3
Since the pace current of 02 is limited to a small value by the resistors 602 and 604, the oscillation force of the inverter 3 is weak, and only a low voltage MW is applied to the secondary winding of the oscillation transformer 306.
Don't wake up. In this state, only preheating of the filament of the fluorescent lamp and weak discharge are performed, but the fluorescent lamp does not light up. On the other hand, the capacitor 605ill of the delay circuit 6:
It is charged by the voltage across the resistor 603, and when the terminal voltage of this capacitor 605 reaches a predetermined level, the thyristor 601 is triggered and becomes conductive. As a result, a predetermined base frost and current flow through the bh transistors 301 and 302, and the oscillation force of the inverter 3 becomes in a steady state. Therefore, a predetermined voltage is generated in the secondary winding 3c of the oscillation transformer 3060, and the light lamp of the load 4 is turned on.

As mentioned above, if the resistor 505 is connected in parallel to the first capacitor 501 of the voltage divider circuit, the smoothing effect of the capacitors 501 and 502 will be effective when the load 4 is removed and there is no load. Even if it gets bigger, the resistor 505
Since the pace bias is appropriately supplied to all of the transistors 301 and 503, the pace bias of the transistors 301 and 302 can be stabilized, and oscillation can be prevented from becoming unstable. In the inventor's experiment, 11
Is it negative when the constants of each component are set to appropriate values so that one 0W fluorescent lamp is used? If you remove ll74,
It has been found that if the resistance value of the resistor 505 is set so that a current of 5 to 10 mA flows through the resistor 505, the secondary no-load voltage of the oscillation transformer 306 is stabilized, and starting is also good. In addition, when one 40W fluorescent lamp is used as load 4, the resistor 505 is set to 0.5 to 5. When the resistance value of resistor 505 is set so that the current of Oyl A flows,
It has become clear that similar effects can be obtained.

In the example of FIG. 2, the resistor 505 is connected to the first capacitor 5.
01, but this resistor 505 is connected to both ends of the first
It is sufficient to connect the capacitor 501 in parallel between the positive output terminal A of the full-wave rectifier circuit 102 and the terminal C on the resistor 503 side of the second capacitor 502, or between the positive terminal of the full-wave rectifier circuit 102. A resistor 505 may be connected between the output terminal A and the common connection point of the resistors 304 and 305.

In particular, the resistor 505 is connected to the positive output terminal A of the full-wave rectifier circuit 102.
If the resistor 604 is connected between the resistor 604 and the connection point of the resistors 304 and 305, the resistor 604 can be omitted.

As shown in FIG. 2, when the starting delay circuit 6 is provided, the load 4
When the lamp is a lighting lamp, the filament can be sufficiently preheated, so that early blackening of the end of the lighting tube can be prevented. However, when such a delay circuit is provided, the voltage applied to the capacitor 502 increases after the power is turned on until the switch (thyristor 601) of the delay circuit 6 becomes conductive. It is necessary to use something. Therefore, in the example shown in Fig. 2, a Zener diode 506 is connected,
The voltage across the capacitor 502 is connected to the Zener diode 5.
The Zener voltage is kept below the zener voltage of 06. In this way, it is possible to prevent a high voltage from being applied to the capacitor 502, so that an inexpensive capacitor with low pressure control can be used as the capacitor 502.

Furthermore, if the Zener diode 506 is connected as described above, the potential at six points will be constant at the time of starting, so the resistors 602 and 603 and the capacitor 60 of the starting delay circuit 6 will be connected.
5, the timer circuit can be operated accurately.

Therefore, even when the power supply voltage is higher than the specified value, a predetermined delay time can be obtained, and the filament of the fluorescent lamp can be sufficiently preheated.

Next, FIG. 3 shows an embodiment of the second invention of the present application,
In this embodiment, a smoothing circuit 7 consisting of a smoothing resistor 701 and a smoothing capacitor 702 is connected in parallel to both ends of the second capacitor 502. Further, in this example, the resistor 505 is connected to the positive output terminal A of the full-wave rectifier circuit 102, the resistor 7ON of the smoothing circuit 7, and the capacitor 702.
is connected to the connection point. Other points are similar to the example shown in FIG. When the smoothing circuit 7 is added in this way, the bases of the transistors 301 and 302 are energized with a voltage smoothed in two stages by the smoothing effect of the resistor 503 and the capacitor 502 and the smoothing effect of the smoothing circuit 7. Ru. With this configuration, when the circuit constants are set to perform an appropriate smoothing effect on 6oH7,
50) Stable operation can be achieved by applying an appropriate smoothing effect to iz.

In the experiment conducted by the present inventor, one 40W fluorescent lamp was used as the load 4 in FIG. 5, and the power supply voltage i 200
V, the capacitance of capacitor 501 is 1μF, the capacitance of capacitors 502 and 702 is 22μF, the resistance value of resistor 503 is 1500, the resistance value of resistor 505 is f
f 68 KΩ, the resistance value of resistor 701 is 390, the resistance value of resistor 604 is 10K (1, resistor 304.305
When both resistance values were set to 4700, stable operation could be performed using both 50) Iz and 60 Hz power supplies. On the other hand, if the smoothing circuit 7 is not provided, it is difficult to perform stable operation with both the SOH and 60 Hz power supplies, and it is especially difficult to perform stable operation for a long time with the 60 Hz power supply. If a constant was set for , it was inevitable that the operation would become unstable immediately after starting when starting at a low temperature using a 50 Hz power supply.

In the above embodiment, a push-pull type circuit is used as the transistor inverter, but the present invention can also be applied to a case where a single-empty type inverter is used. Further, the load is not limited to a discharge lamp, but may also be an electric motor, a charger for a storage battery, or the like.

Although the above embodiment is provided with a delay circuit at the time of starting,
Of course, this delay circuit is omitted when driving a load that does not require a delay operation at startup. If this delay circuit is omitted, the Zener diode 506
As described above, according to the invention, by connecting a relatively high-resistance resistor in parallel to the first capacitor of the voltage divider circuit, it is possible to This can prevent the base energization of the inverter's transistors from becoming unstable due to the increased smoothing effect of the capacitor in the voltage divider circuit when the situation approaches can be prevented from occurring. In particular, according to the second invention of the present application, circuit constants can be set so as to perform stable operation for both 50I (z and 60H2 power supplies), and a power supply device that can be used in common for both 5011z and 60Hz power supplies is provided. Obtainable.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing a circuit of a power supply device previously proposed by the present inventor, and FIGS. 2 and 3 are connection diagrams showing different embodiments of the present invention. ■...Power supply circuit, 3...Transistor inverter,
301.302...Transistor, 303...Capacitor, 304.305...Resistor, 306...Oscillating transformer, 4...Load, 5...Voltage dividing circuit, 501
...first capacitor, 502...second capacitor, 503...resistor, 504...diode, 5
05...Resistor, 506...Zener diode. Agent Patent Attorney Hidetoshi Matsumoto

Claims (1)

[Scope of Claims] (1) A full-wave rectifier circuit connected to an AC power source, a first capacitor having one end coupled to the positive output terminal of the full-wave rectifier circuit, and the other end of the first capacitor coupled to the positive output terminal of the full-wave rectifier circuit. A voltage divider circuit having a second capacitor connected at one end and the other end connected to the negative output terminal of the full-wave rectifier circuit; 1. A power supply device comprising a transistor inverter that is energized to operate, characterized in that: 1. a resistor is connected in parallel to the first capacitor. (2) One end of the second capacitor of the voltage dividing circuit is connected to the first capacitor.
The power supply device according to claim 1, which is directly connected to the other end of the capacitor. (3) The power supply device 1 according to claim 1, wherein one end of the second capacitor of the voltage dividing circuit is coupled to the other end of the first capacitor via a resistor. (4) The voltage dividing circuit includes a diode connected in parallel to the second capacitor with an anode facing the negative output terminal side of the full-wave rectifier circuit. Power supply listed. (5) A patent in which the voltage divider circuit includes a diode connected in parallel to the series circuit of the second capacitor and the resistor with the anode facing the negative output terminal side of the full-wave rectifier circuit. A power supply device according to claim 5. (6) The voltage dividing circuit includes a Zener diode connected in parallel to the second capacitor with its anode facing the negative output terminal side of the full-wave rectifier circuit. The power supply device according to any one of Item 5. A full-wave rectifier circuit connected to an AC power supply, a first capacitor having one end coupled to the positive output terminal of the full-wave rectifier circuit, and a first capacitor having one end coupled to the other end of the first capacitor and another a voltage divider circuit having a second capacitor whose end is coupled to the negative output terminal of the full-wave rectifier circuit; and a transistor inverter whose pace is energized and operated by the voltage across the second capacitor of the voltage divider circuit. A power supply circuit characterized in that a resistor is connected in parallel to the first capacitor, and a smoothing circuit is connected in parallel to the second capacitor. ) One end of the second capacitor of the voltage dividing circuit is directly connected to the other end of the first capacitor.
i? Claim 7: The power supply device according to Claim 7 (9) One end of the second capacitor of the voltage dividing circuit is coupled to the other end of the first capacitor via a resistor. Power supplies listed in section. θ(ll) The voltage dividing circuit includes a diode connected in parallel to the second content with an anode facing the negative output terminal side of the full-wave rectifier circuit. Power supply device.Ql+ Patent, wherein the voltage divider circuit includes a diode connected in parallel to the series circuit of the second capacitor and the resistor, with the anode facing the negative output terminal side of the full-wave rectifier circuit. The power supply device according to claim 9. The voltage dividing circuit includes a Zener diode connected in parallel to the second capacitor with an anode facing the negative output terminal side of the full-wave rectifier circuit. A power supply device according to any one of claims 7 to 11.