JP2007287853A - Electrostatic electricity protection circuit, signal line, and power supply line - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an staticelectricity protection circuit, signal lines, and power supply lines for protecting an internal circuit also from staticelectricity superimposed from a ground line. <P>SOLUTION: The staticelectricity protection circuit 101 of a circuit board including a signal line 102 connected to the internal circuit 106 has a structure provided with a bi-directional constant voltage diode 104 connected between the signal line 102 and ground line 103 and a capacitor 105 connected in series to the bi-directional constant voltage diode 104. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic protection circuit, a signal line, and a power supply line for electrostatic protection of a circuit board used for electronic information equipment and the like, and in particular, electrostatic protection that can protect an internal circuit from static electricity superimposed from a ground line. The present invention relates to a circuit, a signal line, and a power line.

  A circuit board used for electronic information equipment has a problem that an element constituting the internal circuit is damaged due to static electricity superimposed on a signal line, a power supply line, or the like, and an internal circuit malfunctions due to this.

  A conventional static electricity protection circuit for protecting the internal circuit from the static electricity thus superimposed will be described with reference to FIG.

  FIG. 3 is a circuit diagram showing a conventional electrostatic protection circuit.

  In the static electricity protection circuit shown in FIG. 3, measures are taken to prevent the static electricity superimposed from the signal line 301 from being bypassed to the ground line 302 via the capacitor 304 and flowing into the internal circuit 303.

Moreover, in patent document 1, when static electricity is applied to a signal terminal, the static electricity protection circuit for protecting the internal circuit connected to this signal terminal from static electricity is comprised using an inductance element, a diode, etc. An electrostatic protection circuit has been proposed.
JP 2005-117000 A

  However, in the conventional antistatic circuit described with reference to FIG. 3, the static electricity superimposed from the ground line 302 is very likely to flow into the internal circuit 303, causing damage to the device and malfunction.

  Further, the configuration having only the capacitor 304 has a drawback that the signal line 301, the internal circuit 303, and the like are easily subjected to the potential impact of the applied static electricity.

  The invention of Patent Document 1 is effective against static electricity superimposed from the signal line, but the internal circuit cannot be sufficiently protected against static electricity superimposed from the ground line, resulting in deterioration of the element. Was causing damage and malfunction.

  Therefore, an object of the present invention is to provide an electrostatic protection circuit, a signal line, and a power supply line that can protect an internal circuit from static electricity superimposed from a ground line.

  In order to achieve the above object, the invention according to claim 1 is an electrostatic protection circuit for a circuit board having a signal line connected to an internal circuit, and a bidirectional constant voltage diode connected between the signal line and ground. And a capacitor connected in series to the bidirectional constant voltage diode.

  According to a second aspect of the present invention, there is provided an electrostatic protection circuit for a circuit board having a power supply line connected to an internal circuit, a bidirectional constant voltage diode connected between the power supply line and a ground, And a capacitor connected in series with the direct voltage diode.

  According to a third aspect of the present invention, in the signal line connected to the internal circuit, a bidirectional constant voltage diode connected between the ground line and a capacitor connected in series to the bidirectional constant voltage diode. It is characterized by comprising.

  In the power supply line connected to the internal circuit, a bidirectional constant voltage diode connected between the ground line and a capacitor connected in series to the bidirectional constant voltage diode is provided. It is characterized by comprising.

  According to the present invention, the bidirectional constant voltage diode connected between the signal line and the ground, and the capacitor connected in series with the bidirectional constant voltage diode are provided. The internal circuit can be protected from static electricity.

  Furthermore, according to the present invention, because the bidirectional constant voltage diode connected between the power supply line and the ground, and the capacitor connected in series to the bidirectional constant voltage diode, There is an effect that power consumption can be suppressed by preventing leakage current.

  First, a circuit diagram of an electrostatic protection circuit according to the present invention will be described with reference to FIG.

  FIG. 1 is a circuit diagram of a circuit to which an electrostatic protection circuit 101 according to the present invention is connected.

  As shown in FIG. 1, an electrostatic protection circuit 101 is connected between a signal line 102 and a ground line 103 having high-frequency conduction.

  Even if the signal line 102 is a power supply line, the electrostatic protection circuit 101 according to the present invention can be used.

  As shown in FIG. 1, the electrostatic protection circuit 101 has a configuration in which a bidirectional type constant voltage diode 104 and a capacitor 105 are connected in series.

  The bidirectional type constant voltage diode 104 can keep the electrostatic voltage superimposed regardless of the direction constant.

  Therefore, static electricity superimposed from the ground line 103 through the static electricity protection circuit 101 can be suppressed to a certain value or less.

  Therefore, the electrostatic protection circuit 101 suppresses not only the static electricity superimposed from the signal line 102 but also the static electricity superimposed from the ground line 103 through the electrostatic protection circuit 101 in the conventional technique, and deterioration of elements constituting the internal circuit 106, Damage and malfunction of the internal circuit 106 can be prevented.

  Further, since the capacitor 105 allows static electricity to pass but cuts the direct current component, the leakage current from the bidirectional type constant voltage diode 104 can be cut.

  Therefore, when the signal line 102 is a power supply line, an effect of sufficiently suppressing power consumption can be obtained.

  The bidirectional type constant voltage diode 104 and the capacitor 105 of the electrostatic protection circuit 101 may be connected in series between the signal line 102 or the power supply line and the ground line 103. As shown in FIG. Instead of being connected to the ground line 103, a configuration in which the bidirectional type constant voltage diode 104 is connected to the ground line 103 may be adopted.

  Next, an electrostatic protection circuit according to the present invention used for electronic information equipment will be described with reference to FIG.

  FIG. 2 is a diagram showing an outline of a circuit of a control panel used in the electronic information device.

  In a control panel of an electronic information device equipped with a switch operated by a human fingertip, static electricity passing through the human body easily flows into an internal circuit.

  Therefore, as shown in FIG. 2, by placing an electrostatic protection circuit 203 in which a bidirectional type constant voltage diode 201 and a capacitor 202 are connected in series between the signal line and the ground line, a person presses the switch 204. An LSI (Large Scale Integration) 205 that is an internal circuit can be protected from static electricity that sometimes flows in through the human body and overlaps.

  Thus, since the electrostatic protection circuit according to the present invention has a configuration in which the bidirectional type constant voltage diode and the capacitor are connected in series, the internal circuit not only from the signal line but also from the static electricity superimposed from the ground line. In addition, it is possible to realize a circuit that functions with power saving.

  The present invention can be used in an electrostatic protection circuit, a signal line, and a power supply line that have high-frequency continuity with a ground line and need to protect an internal circuit from static electricity.

  According to the present invention, the internal circuit can be protected from static electricity superimposed from the ground line.

The circuit diagram of the circuit to which the electrostatic protection circuit 101 was connected. The figure which shows the outline of the circuit of the control panel used for an electronic information device. The circuit diagram of the conventional electrostatic protection circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Electrostatic protection circuit 102 Signal line 103 Ground line 104 Bidirectional type constant voltage diode 105 Capacitor 106 Internal circuit 201 Bidirectional type constant voltage diode 202 Capacitor 203 Static electricity protection circuit 204 Switch 205 LSI
301 Signal Line 302 Ground Line 303 Internal Circuit 304 Capacitor

Claims (4)

In an electrostatic protection circuit of a circuit board having a signal line connected to an internal circuit,
A bidirectional constant voltage diode connected between the signal line and ground;
And a capacitor connected in series with the bidirectional constant voltage diode. In an electrostatic protection circuit of a circuit board having a power line connected to an internal circuit,
A bi-directional constant voltage diode connected between the power line and the ground;
And a capacitor connected in series with the bidirectional constant voltage diode. In the signal line connected to the internal circuit,
A bidirectional constant voltage diode connected between the ground line and
A signal line comprising: a capacitor connected in series to the bidirectional constant voltage diode. In the power line connected to the internal circuit,
A bidirectional constant voltage diode connected between the ground line and
A power line comprising: a capacitor connected in series to the bidirectional constant voltage diode.

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