JP2000184576A - Lightening surge protector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightening surge protector which prevents breakdown of circuit elements due to lightening surge even in the case of such a constitution that a turner block is separated from a power circuit block. SOLUTION: The path 12 of a lightening surge applied from an antenna 1 through a tuner 2 is clarified by installing a ground dedicated to lightening surges, isolated from the ground 4 of peripheral circuits. Even in the case of such a constitution that a tuner block 8 is isolated from a power circuit block 9, the tuner block 8 is electrically connected with the power circuit block 9 using a magnetically shielded signal cable 5 containing a peripheral conductive portion 7, and the peripheral conductive portion 7 the resistance value of which is lower than that of an internal signal line 6 is used as the path 12 of lightening surges to return them to the power circuit block 9, breakdown of circuit elements due to lightening surges being thereby prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protection device against lightning surge used for a display device using a liquid crystal.

[0002]

2. Description of the Related Art A conventional technique will be described below with reference to FIG. In a conventional device for preventing destruction of a circuit element against a lightning surge in a display device, an antenna 1 for receiving a television signal is connected to a tuner 2. Electrodes A and B are respectively connected to the power supply path live line 16 and the neutral line 10 between the outlet 13 and the fuses 14 and 15, and electrodes C and B are provided opposite to the electrodes A and B.
Is provided. Further, the electrode C was connected to the ground portion 3 near the tuner 2. (Japanese Patent Laid-Open No. 10-1269
No. 49)

[0003]

As in the prior art described above, simply connecting the ground portion near the tuner to the electrode facing the power supply line separates the ground portion near the tuner from the ground portion of another signal system circuit. Therefore, there is a problem in that a lightning surge enters another electronic component before the surge returns to the power supply line, and the circuit element is destroyed.

Further, when the ground portion near the tuner is simply connected to the electrode near the power supply line, it is effective when the tuner and the power supply circuit are close to each other. When the power supply circuit block is separated, the resistance value of the connection line becomes high, which makes it unsuitable as a lightning surge path. As a result, there is a problem that a lightning surge enters a circuit element of a peripheral circuit, and the circuit element is destroyed.

The present invention has been made in view of the above problems, and provides a surge protection device that reliably prevents the destruction of circuit elements due to a lightning surge, even if the tuner block and the power supply circuit block are separated.

[0006]

Means for Solving the Problems To solve the above problems,
The lightning surge protection device of the present invention clarifies the lightning surge path by providing a lightning surge dedicated ground separated from the ground of the peripheral circuit for the lightning surge applied from the antenna through the tuner.

Even when the tuner block and the power supply circuit block are separated from each other, the power supply circuit block is electrically connected to the tuner block by a magnetically shielded signal cable having an outer conductor. In addition, by returning the outer conductive portion having a lower resistance value than the internal signal line to the power supply circuit block as a lightning surge path, the circuit element is prevented from being destroyed by the lightning surge.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 of the present invention uses a magnetically shielded signal cable for a lightning surge applied from an antenna through a tuner, and uses a power supply line for the lightning surge. The use of a magnetic shield part, that is, an outer conductive part having a lower resistance value than the internal signal line, as a return path to the circuit element prevents damage to circuit elements due to a lightning surge. Even when the block and the power supply circuit block are separated from each other, the power supply circuit block is electrically connected from the tuner block with a magnetically shielded signal cable having a conductor at the outer periphery, and the internal signal line is used. By returning the outer conductive portion having a low resistance value to the power supply circuit block as a lightning surge path, it has an effect of preventing destruction of circuit elements due to the lightning surge.

According to a second aspect of the present invention, for a lightning surge applied from an antenna through a tuner, a lightning surge dedicated ground separated from a ground of a peripheral circuit in order to clarify a lightning surge path. And electrically connect a printed circuit board block having a power supply circuit to a printed circuit board block having a tuner, and generate a magnetically shielded lightning surge having an outer conducting portion having a lower resistance value than an internal signal line. A signal cable for returning to the power supply circuit block, and a printed circuit board inserted between the ground for exclusive use of the lightning surge and the neutral line of the power supply to prevent the destruction of circuit elements due to the lightning surge by returning the lightning surge to the power supply line And a circuit element with a gap according to the pattern of The lightning surge can be separated from other signal system grounds, the ground dedicated to lightning surge can be connected to the power supply circuit block with low impedance, and the lightning surge is returned to the power supply line by the above gap, so that the circuit due to lightning surge It has the effect of preventing the destruction of the element.

An embodiment of the present invention described in claims 1 and 2 of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is an antenna, 2 is a tuner, 3 is a ground portion of a tuner circuit, and 4 is a ground of a peripheral circuit. The lightning surge applied from the antenna 1 through the tuner 2 is propagated to the ground portion 3 of the tuner circuit. Here, the ground portion 3 of the tuner circuit and the ground 4 of the peripheral circuit are separated to clarify the path of the lightning surge, thereby preventing the circuit element of the peripheral circuit from being destroyed by the lightning surge.

Reference numeral 5 denotes a magnetically shielded signal cable, 6 denotes a signal line inside the signal cable, and 7 denotes a conductive portion on the outer periphery of the signal cable. Even if tuner block 8
Even if the power supply circuit block 9 and the power supply circuit block 9 are separated from each other, the magnetically shielded signal cable 5 is used, and a path for returning a lightning surge to the power supply line is more resistant than the magnetically shielded portion, that is, the internal signal line 6. By using the outer conductive portion 7 having a low value, the ground 4 of the peripheral circuit and the lightning surge path 12 can be separated, and the lightning surge path 12 can be kept at low impedance.

A lightning surge is set by inserting a gap 11 (a gap formed by a pattern on a printed circuit board or a circuit element having a gap) between the lightning surge path 12 and the neutral line 10 of the power supply circuit 9. Since it can be returned to the outside, destruction of circuit elements in the set can be reliably prevented.

[0014]

As described above, according to the lightning surge protection device of the present invention, the lightning surge applied from the antenna through the tuner is provided with a lightning surge dedicated ground separated from the signal system ground. In addition, it is possible to clarify the path of the lightning surge and prevent the destruction of circuit elements of the peripheral electric circuit.

Even if the tuner block and the power supply circuit block are separated for design or structural reasons, a magnetically shielded signal cable having an outer conductive portion having a lower resistance than the internal signal line is used. Thus, the lightning surge is propagated to the power supply block with low impedance, and the lightning surge is returned to the power supply line, whereby the destruction of circuit elements due to the lightning surge can be more reliably prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a surge protection device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional surge protection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Tuner 3 Ground part of tuner circuit 4 Ground of peripheral circuit 5 Magnetically shielded signal cable 6 Signal line inside signal cable 7 Conductor on the outer periphery of signal cable 8 Tuner block 9 Power supply circuit block 10 Neutral Line 11 Gap 12 Lightning surge path 13 Outlet 14, 15 fuse 16 Live line

Claims (2)

[Claims] The present invention uses a magnetically shielded signal cable for a lightning surge applied from an antenna through a tuner, and uses a magnetically shielded internal signal line as a path for returning the lightning surge to a power supply line. A lightning surge protection device having an outer conductive portion having a low resistance value. 2. A lightning surge applied from an antenna through a tuner, a lightning surge dedicated ground separated from a ground of a peripheral circuit for clarifying a lightning surge path, and a power supply from a printed circuit board block having a tuner. A signal cable for electrically connecting a printed circuit board block having a circuit, and returning a magnetically shielded lightning surge having an outer conducting portion having a lower resistance value than an internal signal line to a power supply circuit block; A circuit having a spatial gap or gap due to a pattern on a printed circuit board inserted between the lightning surge dedicated ground and the neutral line of the power supply to prevent the destruction of circuit elements due to the lightning surge by returning the lightning surge to the power supply line A lightning surge protection device comprising an element.