JPH0333180Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is provided on the commercial AC input side of various electronic devices, and is capable of handling at least two types of commercial AC inputs with different voltage values from the same output terminal. The present invention relates to a voltage switching circuit that outputs voltages of the same value.

Conventional technology As a commercial AC power source, for example in North American countries,
There are countries that mainly use AC115V systems, and countries such as European countries that mainly use AC230V systems. In order to realize electronic equipment that can be used commonly in countries with different commercial AC power supplies, a voltage switching circuit is required on the commercial AC input side of the electronic equipment to generate the same output voltage for commercial AC of different voltages. is necessary. As such a voltage switching circuit, for example,
For AC115V system, voltage doubler rectification or
The most well-known voltage switching circuit is one that switches to normal rectification for an AC 230V system and obtains DC outputs of approximately the same value for two different commercial AC power systems.

FIG. 1 is a diagram showing a general circuit configuration of this type of voltage switching circuit. In FIG. 1, e is a commercial AC power source. The commercial AC power source e is, for example,
It consists of two types of voltage systems, such as AC115V system or AC230V system. 1 and 2 are commercial AC input lines,
3 is a bridge rectifier circuit composed of diodes _D1 to _D4 . A capacitor circuit 4 is connected to the positive (+) side and the negative (-) side of the bridge rectifier circuit 3. The capacitor circuit 4 is constructed by connecting at least two capacitors C ₁₁ and C ₁₂ of substantially the same capacity in series.
Then, the middle point of the capacitor circuit 4, that is, the connection point A of capacitors _C11 and _C12 , and the bridge rectifier circuit 3
A changeover switch 5 is connected between one AC input terminal B of the
It has a circuit configuration that connects. 61 and 62 are AC lines, and 7 and 8 are output terminals.

In the above voltage switching circuit, the commercial AC power supply e
Assume that the system is selected between the AC 115V system and the AC 230V system, and when the AC 230V system is selected, the changeover switch 5 is opened. This results in a circuit configuration in which the circuit including the selector switch 5 is removed.
The AC input of 230V AC supplied from the commercial AC power supply e is full-wave rectified by the bridge rectifier circuit 3, and the rectified output is smoothed by the smoothing circuit composed of capacitors _C11 and _C12 , and then sent to the output terminals 7-8. From between
Rectified DC output V ₀ compatible with AC230V can be obtained.

When the AC115V system is selected as the commercial AC power source e, the selector switch 5 is closed. Then, a voltage doubler rectifier circuit is formed by the diodes D ₁ and D ₃ and the capacitors C ₁₁ and C ₁₂ that constitute the bridge rectifier circuit 3, and a voltage doubler rectifier output V ₀ having substantially the same value as in the case of AC230V input is obtained.

Problems with the Prior Art By the way, in a commercial AC power supply system, one of the two wires is grounded, as is well known. In this case, in accordance with safety standards for electronic equipment destined for North American countries, fuse 9 must be inserted only on the non-grounded AC input line 1 side of the two-wire AC input lines 1 and 2, as shown in Figure 2. , it is prohibited to insert a fuse into AC input line 2 on the ground side, whereas in electronic equipment for European countries, AC input lines 1 and 2 are
In many cases, it is mandatory to insert fuses 9 and 10 in both. In North American countries, this is the socket 11 on the commercial AC power supply side and the plug 12 on the side of the electronic device inserted into this socket 11.
The relationship between the plug pins 13 and 14 is fixed, and the plug pin 13 that should be connected to the grounded AC line 62 side will not be accidentally inserted into the non-grounded AC line 61 side. By inserting it into the ground side AC line 61, if a short circuit or the like occurs, the commercial AC power supply is cut off on the non-ground side, thereby reliably preventing electric shock on the electronic equipment side. Assuming that fuses 9 and 10 are inserted into both AC input lines 1 and 2, if fuse 9 on the non-grounded side is not blown and fuse 10 on the grounded side is blown, the electronic equipment side This is because they believed that it would become impossible to prevent electric shock accidents and would pose a safety problem.

On the other hand, in European countries, the relationship between the plug 12 on the power supply equipment side and the socket 11 on the commercial AC power supply side is generally not fixed, and the plug pin 1
3 and 14 are connected to the non-grounded AC line 61 or the grounded AC line 62 depending on chance at the time. Therefore, like North American countries,
If a fuse is inserted into only one side of the AC input lines 1 and 2, and it is connected to the ground side, it will be powerless in case a ground fault occurs on the electronic equipment side. Therefore, if fuses 9 and 10 are inserted into both AC input lines 1 and 2, socket 1
Regardless of the connection state of the plug 12 to the fuse 1, either one of the fuses 9 and 10 can be blown in the event of a ground fault.

As mentioned above, the usage of fuses 9 and 10 for AC input lines 1 and 2 is different between North American countries and European countries. For this reason, it is impossible to realize an electronic device that can handle both.

Purpose of the present invention The present invention solves the above-mentioned problems, such as
The purpose of the present invention is to provide a voltage switching circuit that can sufficiently handle commercial AC power supplies with different voltage values such as 115V AC and 230V AC, even if the usage of the fuse to be inserted into the AC input line is different. do.

Structure of the Present Invention In order to achieve the above object, the present invention has a pair of input terminals that receive at least two types of commercial alternating current having different voltage values that are selectively inputted, and a In a circuit that switches the voltage so that substantially the same value of voltage is output from the same output terminal for alternating current, a fuse is inserted and connected in series in the middle of each of a pair of alternating current input lines led from the input terminal. , a switch that turns on and off in conjunction with voltage switching is connected in parallel to one of these fuses.

Embodiment FIG. 4 is an electrical circuit connection diagram of a voltage switching circuit according to the present invention. In the figures, the same reference numerals as in FIGS. 1 to 3 indicate the same components. This embodiment shows a voltage switching circuit using voltage doubler rectification/bridge rectification switching as explained in FIG. 1, and has a pair of input terminals a,
A fuse 15 is connected to each of the pair of AC input lines 1 and 2 led from the input terminals a and b.
16 are inserted and connected in series, and these fuses 1
5, 16, for example, AC input line 2
A switch 17 that is turned on and off in conjunction with the changeover switch 5 is connected in parallel to the fuse 16.

In the voltage switching circuit described above, when the AC230V system is selected as the commercial AC power source, the changeover switch 5 is turned off. As a result, the AC 230V input is full-wave rectified by the bridge rectifier circuit 3, smoothed by the smoothing filter circuit composed of capacitors C ₁₁ and C ₁₂ , and then output from between the output terminals 7 and 8.
Rectified DC output V ₀ compatible with AC230V can be obtained.
Here, since the switch 17 is also turned off in conjunction with the turning off of the changeover switch 5, both the fuses 15 and 16 are inserted in series into the AC input lines 1 and 2. This circuit corresponds to the circuit configuration of the AC input circuit required for electronic equipment for European countries as explained in FIG.

On the other hand, when the AC115V system is selected as the commercial AC power source e, the selector switch 5 is closed. As a result, the diodes constituting the bridge rectifier circuit 3
A voltage doubler rectifier circuit is configured by D ₁ , D ₃ and capacitors C ₁₁ , C ₁₂ , and a voltage doubler rectifier output V ₀ having substantially the same value as in the case of AC230V input is obtained. At the same time,
The switch 17 is turned on in conjunction with the changeover switch 5, and the fuse 16 is shorted by the switch 17. Therefore, if the AC input line 2 containing the fuse 16 is made to correspond to the ground side, the circuit configuration shown in FIG. 2 will be obtained, and a voltage switching circuit suitable for North American countries will be obtained.

In the above embodiment, a voltage switching system using a voltage doubler rectifier circuit and a bridge circuit was shown, but as shown in FIG. 5, a voltage switching system using tap switching of the transformer 18 may also be used. In FIG. 5, each of the commercial AC input lines 1 and 2 is connected to a fuse 15,
16 to both ends of the winding N ₁ of the transformer 18 and to the middle tap P ₁ of the transformer 18 and the winding
A selector switch 5 is connected between one end of N ₁ and a fuse 16 inserted into the AC input line 2 side.
A switch 17 that is turned on and off in conjunction with the on and off operations of the selector switch 5 is connected in parallel. D ₅ and D ₆ are rectifier diodes, L is a choke coil, and C is a capacitor.

In the case of this example as well, as a commercial AC power supply,
When AC230V system is selected, selector switch 5
Turn off. Then, an AC input of 230V AC is applied to both ends of the winding _N1 of the transformer 18, and is rectified and smoothed by the rectifier circuits _D5 , _D6 and smoothing circuits L, C connected to the winding _N2 , and then output to the output terminal. From 7-8
Rectified DC output V ₀ compatible with AC230V can be obtained.
Here, since the switch 17 is also turned off in conjunction with the turning off of the changeover switch 5, both the fuses 15 and 16 are inserted in series into the AC input lines 1 and 2. This circuit corresponds to the circuit configuration of the AC input circuit required for electronic equipment for European countries as explained in FIG.

On the other hand, when the AC115V system is selected as the commercial AC power source e, the selector switch 5 is closed. As a result, the effective number of turns of the winding N ₁ of the transformer 18 is halved, and the turns ratio in relation to the winding N ₂ is _{doubled .} A voltage approximately twice that applied to the side is induced. Therefore, from the output terminals 7 and 8, a voltage doubler rectified output V ₀ having substantially the same value as in the case of AC230V input is obtained. At the same time,
The switch 17 is turned on in conjunction with the changeover switch 5, and the fuse 16 is short-circuited by the switch 17. Therefore, a voltage switching circuit compatible with North American countries can be obtained.

Effects of the Present Invention As described above, the present invention has a pair of input terminals that receive at least two types of commercial alternating current having different voltage values selectively input, and the commercial alternating current that is input to the input terminals. In contrast, in a circuit that switches voltages so as to output voltages of substantially the same value from the same output terminal, a fuse is inserted and connected in series in the middle of each of a pair of AC input lines led from the input terminal, The feature is that a switch that turns on and off in conjunction with voltage switching is connected in parallel to one of these fuses, so that commercial AC power sources with different voltage values, such as AC115V and AC230V systems, can be input. Even if the usage of the fuse to be inserted into the AC input line is different, it is possible to provide a voltage switching circuit that can sufficiently handle the usage.

[Brief explanation of the drawing]

Figure 1 is an electric circuit connection diagram of a conventional voltage switching circuit, Figure 2 is a commercial AC input circuit diagram required for electronic equipment for North American countries, and Figure 3 is a commercial AC input circuit required for electronic equipment for European countries. Figure, 4th
The figure is an electric circuit connection diagram of a voltage switching circuit according to the present invention, and FIG. 5 is an electric circuit connection diagram of another embodiment. 1, 2... Commercial AC input line, 5... Changeover switch, 7, 8... Output terminal, 15, 16... Fuse, 17... Switch.

Claims (1)

[Claims for Utility Model Registration] (1) A device having a pair of input terminals for receiving at least two types of commercial alternating current having different voltage values selectively input, and for receiving the commercial alternating current input to the input terminals. , in a circuit that switches voltages so as to output voltages of substantially the same value from the same output terminal, a fuse is inserted and connected in series in the middle of each of a pair of AC input lines led from the input terminal, and these fuses are connected in series. A voltage switching circuit characterized in that a switch that turns on and off in conjunction with voltage switching is connected in parallel to one side of the circuit. (2) The voltage according to claim 1 of the utility model registration claim, characterized in that the voltage is switched so that bridge rectification is performed when one of the two types of commercial AC is input, and voltage doubler rectification is performed when the other is input. switching circuit.