JPH0536256Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high frequency transformer comprising a coil formed by winding two identical conducting wires as a pair.

[Problems that conventional technology and ideas try to solve]

This type of high frequency transformer is well known as a so-called bifilar winding. However, in order to provide a potential difference between the primary and secondary windings to ensure good transmission characteristics in the high frequency range, it is possible to ground the terminals located on opposite sides of the primary winding as shown in Figure 5. There is a drawback that the secondary side output has opposite polarity with respect to the side input.

Therefore, it is an object of the present invention to provide a high frequency transformer which secures the features of bifilar winding and outputs a signal having the same polarity as an input signal.

[Means and effects for solving the problem] In order to achieve this object, the present invention uses two identical conductors 1, 1a and 2, as shown in FIG.
The coil 2a is composed of two coils 3 and 4, each of which is wound as a pair. Then, the ends 6, 7 of one conductor wire 1, 2 of each coil 3, 4 are connected to each other in a positive manner, and the ends 6, 7 of the other conductor wire 1a, 2a of each coil 3, 4 are connected to each other in a positive manner. end 5a at the opposite position,
8a were connected to each other. The remaining ends 5 and 8 are used as primary or secondary terminals, and the ends 6a and 7a are used as secondary or primary terminals.

For example, as shown in FIG. 2, if a +V input signal is supplied to the end 5 with the end 8 grounded, by grounding the end 6a, the end 7a will have the same polarity of +V. Output signals of the same level are obtained. At this time, a potential difference of +1/2 V is generated between the windings of the coil 3 on the primary side with respect to the secondary side, and a potential difference of -1/2 V is generated between the windings of the coil 4, so that the transmission characteristics are not impaired.
In other words, the potential between the primary and secondary windings becomes 0, and the unstable phenomenon of transmission impedance caused by the fact that the effective capacitance between the windings is not determined does not occur. Also,
Since the input ends 5, 8 and the output ends 6a, 7a are located farthest from each other, the common mode current,
That is, the longitudinal current can also be reduced.

In FIG. 2, when the ends 8, 6a are floated, the ends 6, 7 are at 0 potential on the primary side, and the ends 5a, 6a are at 0 potential on the secondary side.
Ends 5 and 7a are +1/2V, ends 8 and 7a are -1/2V
becomes. Therefore, a potential of +1/2V between the windings of the coil 3 and -1/2V between the windings of the coil 4 is generated, and similarly good transmission characteristics and a common mode current reduction effect are ensured. Ru. Moreover, the ends 5 and 8 on the primary side are the ends 5a and 8a at 0 potential on the secondary side.
Furthermore, since the ends 6a and 7a on the secondary side are located at the 0 potential ends 6 and 7 on the primary side, they are more effective in reducing the common mode current.

[Example of idea]

FIG. 3 shows a high frequency transformer 15 according to the present invention, 10 is a first bifilar coil wound around a core 19, and two conductive wires 11 and 12 of the same material and shape are paired together. It is wound as. 20 is a second bifilar coil in which the same conductive wires 21 and 22 as the two coils 10 are similarly wound around a common core 19 in the same direction and the same number of turns. In the figure, the number of turns is shown simply. One conductor 11 of bifila coil 10
The end portion 11b of the
0 is connected to the end 21a of one of the conductive wires 21. Terminals 10a and 10b are led out from the unconnected ends 11a and 21b. Regarding the other conductor 12 of the first bifilar coil 10,
End 11 opposite the internally connected end 11b
a is a similar end 21a of the other conducting wire 22 of the bifilar coil 20 and an opposite end 22b;
and an unconnected end 12b,
Terminals 20a and 20b are led out from 22a.
As a result, terminals 10a, 10b or 20a, 2
0b is the primary side input terminal and the other secondary side terminal 2
From 0a, 20b or 10a, 10b, the high frequency transmission impedance is stabilized and signal transmission with less common mode noise is possible according to the principle explained based on FIG. For example, it can be used to transmit signals with a cut-off frequency of about 30 MHz without causing vibrations in the pulse waveform.

FIG. 4 shows an application example in which the same side of the bifilar-wound inductance coil 25 is connected to the input side of the high-frequency transformer 15 shown in FIG. 3 and is floated. When one end of the inductance coil 25 is grounded and an input signal is supplied, the inductance coil 25 can be connected to the high frequency transformer 15 without exhibiting almost any impedance due to cancellation of the signal magnetic flux.
is supplied to the primary side input terminals 10a, 10b of.
On the other hand, each of the input terminals 10a and 10b is in a floating state at high frequencies because each winding of the inductance coil 25 exhibits high impedance to high frequencies.
In other words, in response to common mode noise that is input in the same phase, the coil 25 exhibits high impedance because there is no cancellation of magnetic flux, and in addition to the common mode current suppressing effect of the high frequency transformer 15, the common mode noise is transferred to the secondary side. transmission is further suppressed. Note that the inductance coil 25 may be connected to the secondary side or to both the primary and secondary sides.

[Effect of idea]

As described above, according to the present invention, a high-frequency transformer with excellent high-frequency characteristics, stable transmission impedance, and signals of the same polarity at input and output can be realized with a simple and inexpensive structure using conventional bifilar coils. be done. Moreover, common mode noise is also suppressed.

[Brief explanation of the drawing]

Fig. 1 shows the circuit configuration of the high frequency transformer of the present invention, Fig. 2 is a diagram explaining its operation, Fig. 3 is a schematic plan view of the high frequency transformer according to the embodiment of the present invention, Fig. 4 is a diagram showing an application example, and Fig. 5 is a diagram explaining how to use a conventional bifilar coil as a transformer. 3, 4, 10, 20... coils, 15... high frequency transformer.

Claims (1)

[Scope of utility model registration request] Two coils are formed by winding two identical conductive wires as a pair, the ends of the conductive wires of one of these coils are positively connected to each other, and the conductive wire of the other of the coils is connected to each other in a positive manner. A high-frequency transformer in which the ends opposite to the end are connected to each other, and the unconnected end is configured as a primary or secondary input/output terminal.