JPH08308097A - Electronic apparatus - Google Patents

Abstract

PURPOSE: To provide an electronic component which does not deteriorate circuit components on the secondary side even if a lightning, for example, is applied in the electronic components used in the field of CATV. CONSTITUTION: The grounds 15 and 19 of a primary circuit 13 and a secondary circuit 14 formed on a printed circuit board 12 are isolated and the grounds 15 and 19 of the primary circuit 13 and secondary circuit 14 are connected to the chassis 11 respectively at different positions 21, 22. Therefore, even if lightning or the like is applied to the primary circuit 13, the circuit elements of the secondary circuit 14 are never deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device used in the field of CATV.

[0002]

2. Description of the Related Art A conventional electronic device will be described below.

As shown in FIG. 3, a conventional electronic device has a printed circuit board 2 mounted in a chassis 1 on which a primary side circuit section 3, a secondary side circuit section 4 and a ground 5 are mounted. It was provided. Further, a discharge gap 7 is provided between the primary side circuit portion 3 and the ground 5 in order to protect electronic equipment by discharge even if there is a lightning surge. Further, a common ground 5 is provided in the primary side circuit section 3 and the secondary side circuit section 4 on the printed circuit board 2.

As a technique similar to this, for example, there are JP-A-3-65021 and JP-A-4-34885.

[0005]

However, in such a conventional configuration, the primary side circuit section 3 and the secondary side circuit section 4 are provided.
Is connected to the ground pattern 5 by a ground pattern 5, so that if lightning or the like is applied to the primary side circuit part 3, this lightning will not be consumed in the discharge gap 7 and the remaining energy will pass through the ground pattern 5 to the secondary pattern. It may be transmitted to the side circuit portion 4 and may deteriorate the circuit components on the secondary side.

The present invention solves such a problem, and an object of the present invention is to provide an electronic apparatus which does not deteriorate the circuit parts on the secondary side even if lightning or the like is applied. .

[0007]

In order to achieve this object, the electronic equipment of the present invention is configured such that the primary side circuit section and the secondary side circuit section formed on a printed circuit board are separated from each other in the ground and the primary side circuit is formed. The parts and the grounds of the secondary circuit part are connected to the chassis at different positions.

[0008]

With this configuration, even if lightning or the like is applied to the primary side circuit section, it becomes difficult for energy such as lightning to be transmitted to the secondary side circuit section. Absent.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of an essential part of an electronic device according to an embodiment of the present invention. In FIG. 1, an electronic device according to the present invention includes a metal chassis 11 and a printed circuit board 12 mounted in the chassis 11 and having electronic components mounted thereon.
And a primary side circuit section 13 and a secondary side circuit section 14 provided on the printed circuit board 12, and the grounds of the primary side circuit section 13 and the secondary side circuit section 14 are provided on the printed circuit board 12. 15 and 19 are formed separately. And
The ground 15 and the ground 19 are separated by an insulating portion 20. Further, the grounds 15 and 19 of the primary circuit section 13 and the secondary circuit section 14 are connected to the chassis 11 at different positions.

The operation of the electronic device configured as described above will be described below. Discharge gaps 16 are provided between the power supply input sections 17 and 18 of the primary side circuit section 13 and the ground 15, respectively. When lightning or the like is applied to the power supply input sections 17 and 18, the discharge due to the lightning surge is generated. appear.

When a lightning surge occurs on the printed circuit board 12, its energy escapes from the connecting portion 21 between the ground 15 and the chassis 11 to the chassis 11. Therefore, this energy does not invade the secondary side circuit section 14 again via the connection section 22, and the lightning surge countermeasure for the secondary side circuit section 14 can be easily performed.

The ground 19 of the secondary side circuit section 14
The distance between the connecting portions 22 connecting the chassis 11 and the chassis 11 is made larger than the distance between the insulating portions 20 between the grounds 15 and 19.

Further, as shown in FIG. 2 (a), the length C of the claw from the chassis 11 to the ground 15 of the primary side circuit portion 13 is determined from the chassis 11 to the secondary side as shown in FIG. 2 (b). It is preferable to make it shorter than the length D of the claw to the ground 19 of the circuit portion 14. Furthermore, the width E of the claw connected to the ground 15 part
Is thicker than the width F of the claw connected to the ground 19. With these measures, the lightning surge is more likely to flow from the ground 15 to the chassis 11, and the intrusion of the lightning surge into the secondary side circuit unit 14 is reduced.

[0015]

As described above, according to the electronic device of the present invention, the grounds of the primary side circuit section and the secondary side circuit section formed on the printed circuit board 12 are separated and the primary side circuit section is Since the grounds of the secondary side circuit section are connected to the chassis at different positions, even if lightning is applied to the primary side circuit section, energy such as lightning is applied to the secondary side circuit section. Since it is hard to transmit, the secondary side circuit components will not be deteriorated.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of an electronic device according to an embodiment of the present invention.

FIG. 2A is a cross-sectional view near the primary side claw portion provided in the electronic device, and FIG. 2B is a cross-sectional view near the secondary side claw portion provided in the electronic device.

FIG. 3 is a plan view of a main part of a conventional electronic device.

[Explanation of symbols]

 11 chassis 12 printed circuit board 13 primary side circuit section 14 secondary side circuit section 15 ground 19 ground 20 insulation section

Claims (4)

[Claims] 1. A metal chassis, a printed circuit board mounted in the chassis and having electronic components mounted thereon, a primary side circuit section and a secondary side circuit section provided on the printed circuit board. An electronic device in which the primary side circuit part and the secondary side circuit part formed on the printed circuit board are separated from each other and the primary side circuit part and the secondary side circuit part are connected to the chassis at different positions. . 2. The electronic device according to claim 1, wherein the distance between the connection claws that connect the ground and the chassis is larger than the distance between the separated grounds. 3. The electronic device according to claim 1, wherein the length of the claw from the chassis to the ground of the primary side circuit section is shorter than the length of the claw from the chassis to the secondary side circuit section. 4. The electronic device according to claim 3, wherein the width of the claw connected to the primary side circuit section is larger than the width of the claw connected to the secondary side circuit section.