JPS63250199A - Mounting system of noise-proof circuit board - 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 [Technical Field] The present invention relates to board mounting that is free from the influence of noise.

[Prior art]

Conventionally, in devices of this type, such as switching power supplies and pulse transformers, when mounting on a board, the circuit is separated from the noise source transformer or coil, or the transformer itself is covered with a short ring or shield case to reduce noise. Since it was designed to prevent the effects, it had the disadvantage of consuming board space and increasing costs.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a board mounting method that eliminates the drawbacks of the conventional example described above and at the same time significantly improves the transfer characteristics of the transformer.

〔Example〕

Figure 1 shows an embodiment of the present invention, where 1 and 2 are iron cores constituting the magnetic circuit of the transformer, 3 is a wire, 4 is a magnetic flux flowing due to the magnetomotive force generated by the 3'' wire, and 5 is a core. 1
The cage magnetic flux 0.6 generated by the magnetic potential difference concentrated in the GAP of the core 2 is a jumper wire that goes around the transformer placed on the board 7, and the cage magnetic flux 5 is placed at a position where it passes through the jumper wire 6. are doing.

Figure 2 shows an equivalent circuit in the configuration shown in Figure 1, where 8 shows the cage inductance parasitic to the cage magnetic flux, and 9 shows the electric resistance of the jumper wire itself that occurs when the cage magnetic flux passes through the short jumper wire 6. , 10 is an exciting inductor.

FIG. 3 shows a further simplified equivalent circuit of FIG. 2.

Figure 4 shows the operating waveforms.

Next, in the above configuration example, when a voltage is applied to the transformer and a magnetomotive force is generated by the winding 3, the main magnetic flux 4 circulates around the iron core.
occurs. However, the iron core has G at the junction of 1 and 2.
Since the connection is made through the AP, most of the magnetomotive force is concentrated in the GAP section due to the magnetic resistance caused by the GAP, so a re-cage magnetic flux is generated as shown in Fig. 2. It acts as an inductance and deteriorates the transfer characteristics of the transformer, and since the re-cage magnetic flux passes through the pattern of the mounting board and returns to the opposing GAP, it induces noise and adversely affects peripheral circuits.

The present invention provides a pattern or jumper wire that goes around the transformer in order to reduce the adverse effects such as the above-mentioned transfer characteristics and noise induction.

To explain the effect of the above jumper wire, as a result of the jumper wire 9 magnetically coupling to the cage inductance 8 in Figure 2, the resistor 11 is connected in parallel due to the effect of the cage inductance 8 and the jumper wire 6 as shown in Figure 3. It becomes the type inserted into .

Therefore, the re-cage inductance 8 is damped by the equivalent resistance 11, improving the waveform transmission characteristics. In addition, since the re-cage magnetic flux is short-circuited by the short jumper wire, the voltage across the re-cage inductance is lowered, and as a result, the influence on the outside can be significantly reduced.

In the above embodiments, a transformer has been described, but the same effect can be obtained with a coil or a motor having a movable part.

〔effect〕

As explained above, by configuring a pattern or jumper wire that goes around the transformer, 1. Noise radiated from the transformer can be reduced at low cost.

2. Improving the transfer characteristics of the transformer can also be achieved at the same time.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining an embodiment, FIGS. 2 and 3 are equivalent circuit diagrams of FIG. 1, and FIG. 4 is a diagram showing operating waveforms. 1 and 2 are the transformer core 3, the wire ring 4, the main magnetic flux 5, the re-cage magnetic flux 6, the short jumper wire 7, the board 8, the re-cage inductor, and the wire 9, the resistance of the short jumper.

Claims (2)

[Claims] (1) On the circuit board on which the transformer or coil is mounted, one
A noise countermeasure board mounting method characterized by having a pattern that creates a short circuit or a low resistance loop over rotation. (2) The noise countermeasure board mounting method according to claim 1, characterized in that the loop is arranged on the board by a jumper wire or the like.