JPH0456378A - Electronic apparatus - Google Patents

Abstract

PURPOSE:To reduce in size and to enhance performance by providing a plurality of legs passing through a circuit board on a ground plate, and electrically connecting the legs to a ground pattern of an integrated circuit mounting surface of the board. CONSTITUTION:A metal ground plate 30 having legs 20' passing through a circuit board 19 is mounted on the opposite side surface of an integrated circuit 1. Since the ends of the legs 20' are soldered to a ground point pattern, dispersed ground points become common ground point in a high frequency manner to obtain a stable operation, and characteristic deterioration such as a decrease in power gain is eliminated. Thus, the dispersed ground points can be strengthened. Thus, since the pattern of the mounting surface of the circuit 1 of the board 19 does not necessarily constitute a ground pattern, peripheral components can be mounted in a high density. An electronic apparatus can be reduced in size and enhanced in performance by ground strengthening.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electronic equipment used, for example, in high frequency equipment.

Conventional technology Conventionally, in this type of electronic equipment, circuit components were connected by soldering the electrodes and patterns using wiring board patterns, and the ground circuits were also connected to the ground of each circuit using the ground pattern. The structure is as follows.

Problems to be Solved by the Invention However, with such a configuration, the integrated circuits and peripheral circuits mounted on the wiring board have become increasingly multi-functional and smaller in size in electronic devices, which have become particularly popular in recent years. Due to the connection pattern of the components, a sufficient ground pattern cannot be formed, and in high frequency circuits, there is a problem in that characteristic deterioration such as a decrease in power gain due to the dispersion of the ground points occurs.

The present invention is intended to solve these problems, and aims to reduce the size and improve the performance of electronic equipment.

Means for Solving the Problems In order to achieve the above objects, the present invention provides a wiring board mounted in a shield case, an integrated circuit having a plurality of electrodes mounted on the wiring board, and a circuit board of the integrated circuit. a grounding plate attached to a surface opposite to the mounting surface, the grounding plate having a plurality of legs penetrating the wiring board, and the legs being connected to a grounding pattern on the mounting surface of the integrated circuit of the wiring board. The configuration is electrically connected.

According to this configuration, the grounding plate attached to the surface opposite to the mounting surface of the integrated circuit electrically connects the grounding electrode of the integrated circuit and the grounding of the peripheral circuit, so that the grounding is sufficiently strengthened. For this reason, the mounting surface of the integrated circuit only requires mounting the integrated circuit and peripheral circuit components and connecting the patterns, making it possible to implement high-density mounting, making it possible to miniaturize electronic equipment and improve its performance by strengthening the ground.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings. FIG. 3 is a block diagram of a tuner for a television receiver using an integrated circuit according to an embodiment of the present invention.

In FIG. 3, 1 is an integrated circuit, 2 is an antenna, 3 is an input terminal, 4 is a VHF/UHF switching circuit, 5 is a VHF input tuning circuit, 6 is a VHF high frequency amplifier circuit, 7 is a VHF interstage double tuning circuit, 8 is a VHF mixing circuit, 9 is a VHF local oscillation circuit, 9A is a VHF oscillation tuning circuit, 9B is a VHF oscillation feedback amplifier circuit, 10 is a tJHF input tuning circuit, 11 is a UH
F high frequency amplifier circuit, 12 is U HF interstage double tuning circuit, 1
3 is a UHF mixing circuit, 14 is a UHF local oscillation circuit, 14
A is a UHF oscillation tuning circuit, J4B is a UHF oscillation feedback amplifier circuit, 15 is an intermediate frequency amplifier circuit, 16 is an intermediate frequency tuning circuit, 17 is a low-pass filter circuit, and 18 is an output terminal.

Next, the mutual relationship and operation of each component of the tuner for a television receiver made up of the above-mentioned components will be explained.

In FIG. 3, taking a VHF signal as an example, the channel signal of the television receiver inputted from the antenna 2 to the input terminal 3 is changed to VHF by the VHF/U HF switching circuit 4.
A signal is supplied to the HF circuit, first tuned by the HF input tuning circuit 5, and then amplified by the VHF high frequency amplifier circuit 6. Furthermore, second tuning is performed in the VHF interstage double tuning circuit 7 and input to the VHF mixing circuit 8. and,
The local oscillation signal generated by the VHF local oscillation circuit 9 is also VH.
It is input to the F mixing circuit 8, converted to an intermediate frequency by the VHF mixing circuit 8, amplified by the intermediate frequency amplification circuit 15, passed through the low-pass filter circuit 17, and output to the output terminal 1.
8 is output.

The UHF signal is similarly processed and output by the UHF circuit.

Here, the integrated circuit construction includes a VHF mixing circuit 8, a UHF mixing circuit 13, a VHF oscillation feedback amplification circuit 9B, a UHF oscillation feedback amplification circuit 14B, and an intermediate frequency amplification circuit 15. In order to obtain stable operation, especially in high frequency bands, it is necessary to strengthen the common grounding point between each circuit and the peripheral circuits.

Next, the actual arrangement of the circuit blocks of the tuner of the television receiver configured as described above will be explained.

FIG. 1(a) is a block layout diagram according to an embodiment of the present invention based on the block diagram of FIG. 3, FIG. 1(b) is a sectional view of essential parts of the present invention, and FIGS. (C) is an embodiment of the ground plate of the present invention.

In FIG. 1, the integrated circuit 1 has a 16-pin configuration, where 1a is a power supply terminal, 1b and 1c are intermediate frequency tuning circuit connection terminals, 1d is a low-pass filter circuit connection terminal,
1e is the mixed circuit ground terminal, If, 1g, and 1h are VH.
F oscillation tuned circuit connection terminal, ]i is the oscillation feedback amplifier circuit ground terminal, 1j-1 and -11 are UHF oscillation tuned circuit connection terminals, Is is the VHF interstage double tuned circuit connection terminal, in is V
HF inter-stage double-tuned circuit connection ground terminal, 1o is a UHF inter-stage double-tuned circuit connection terminal, and 1p is a UHF inter-stage double-tuned circuit connection ground terminal, each of which is connected to a peripheral circuit by a pattern.

In addition, 19 is a wiring board on which the integrated circuit 1 and peripheral circuit components are mounted, 2o is a grounding plate attached to the opposite side of the integrated circuit l, and 21 is a shield case on which the wiring board 1 is mounted.
I am wearing 9.

Next, the operation of the ground plate 2o will be explained.

As shown in FIG. 1(a), the grounding points around the integrated circuit 13 are as shown in FIG. , C is the ground point of the mixed circuit inside the integrated circuit 1,
D is the earth point of the UHF oscillation tuning circuit 14A, E is the earth point of the VHF oscillation tuning circuit 9A, and F is the earth void of the oscillation feedback amplifier circuit inside the integrated circuit 1.
Each is dispersed. In order to strengthen the dispersed grounding points, a metal grounding plate 20 having legs 20' extending through the wiring board 19 is mounted on the opposite side of the integrated circuit 1. The tips of the legs 20゛ are soldered to the ground point pattern, so the dispersed ground points become a common ground point at high frequencies, allowing stable operation and reducing power gain. Deterioration of characteristics also disappears.

As described above, according to this embodiment, the grounding plate 20 having the legs 20' passing through the wiring board I9 is attached to the opposite surface of the integrated circuit 1, and the tip of this leg 20' is connected to the grounding point. Distributed earth points can be strengthened by soldering with the pattern. For this reason, the pattern on the mounting surface of the integrated circuit 1 of the wiring board 19 does not need to constitute a grounding pattern, which enables high-density mounting of peripheral components, thereby achieving miniaturization of electronic devices and higher performance by strengthening the grounding. be able to.

Note that if the area of the metal portion of the ground plate 20 is made large, a shielding effect can be expected for at least the portion of the wiring board 19 on the ground plate 20 side to prevent the influence of an external electric field.

Note that the grounding plate 20 of the present invention may be used in combination with the grounding pattern of a conventional wiring board (in that case, by using one of them depending on the circuit, it is possible to prevent interference with other circuits or feedback caused by the common grounding). Furthermore, in low frequency circuits, interference and feedback due to common impedance between multiple circuits leading to a certain ground point and the ground point can be prevented by devising the shape of the ground plate 20.

Effects of the Invention As is clear from the above description of the embodiments, according to the present invention, a grounding plate having legs that penetrate a wiring board mounted in a shield case is provided on the opposite side of the mounting surface of the integrated circuit. By attaching the legs and electrically connecting the ends of the legs to the pattern of the grounding points, the distributed grounding points can be strengthened, and as a result, the pattern on the mounting surface of the integrated circuit of the wiring board is connected to the grounding pattern. Since there is no need for configuration, high-density mounting of peripheral components is possible.
The effect is that electronic devices can be made smaller and have higher performance due to stronger grounding.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of a block arrangement according to an embodiment of the present invention, FIG. 1(b) is a side sectional view of the main part thereof, and FIGS. A front view, a plan view and a side view showing the embodiment, and FIG. 3 are block diagrams of a tuner for a television receiver using an integrated circuit. DESCRIPTION OF SYMBOLS 1... Integrated circuit, 19... Wiring board, 20... Earth plate, 20゛... Leg part of earth plate 20, 21...
Shield case, A to F...Earth point. Name of agent: Patent attorney Shigetaka Awano

Claims (2)

[Claims] (1) An integrated circuit having a plurality of electrodes attached to a wiring board, and a grounding plate attached to a surface opposite to the mounting surface of the integrated circuit, the grounding plate having legs that penetrate the wiring board. An electronic device comprising a plurality of legs, the legs of which are electrically connected to a ground pattern on a mounting surface of an integrated circuit of the wiring board. (2) Claim 1 in which the wiring board is mounted inside the shield case
Electronic equipment listed.