JPH0546112U - IC for tuner and IC chip for tuner - Google Patents

Abstract

(57) [Summary] [Purpose] To realize a tuner IC with a simple configuration that outputs few unnecessary signals and does not cause interference or beat failure. The tuner IC 21 is provided with output terminals 6 and 7 of a frequency mixing circuit 26 on one side of the ground terminal 5 and input terminals 3 and 4 of an intermediate frequency amplifier circuit 27 on the other side.
To provide. Further, a ground line 35 or a power supply line 36 is laid between the frequency mixing circuit 32 and the intermediate frequency amplifier circuit 33 on the tuner IC chip 31.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tuner IC and a tuner IC chip, and particularly provides a structure suitable for a tuner IC having a frequency mixing circuit and an intermediate frequency amplifier circuit built therein.

[0002]

[Prior Art]

 FIG. 2 shows the internal block and terminal arrangement of a TDA5332 T-type IC manufactured by Philips, which is an example of a tuner IC 41 that receives VHF band and UHF band television broadcasts by a super-heterodyne system. is there.

In FIG. 2, 1 to 20 are terminal numbers assigned in the order of terminal arrangement of the IC 41. In the IC 41, the VHF band received signal input from the input terminals 18 and 19 is amplified by the VHF amplifier circuit 22 and input to the VHF mixing circuit 42. A local oscillation wave is input from the VHF oscillating circuit 24 to the VHF mixing circuit 42, and the received signal is converted into an intermediate frequency signal in the VHF mixing circuit 42 and output to the terminals 13 and 14.

Further, the received signals in the UHF band input from the input terminals 16 and 17 are amplified by the UHF amplification circuit 23 and input to the UHF mixing circuit 43. A local oscillation wave is input to the UHF mixing circuit 43 from the UHF oscillating circuit 25, and in the UHF mixing circuit 43, the received signal is converted into an intermediate frequency signal and output to the terminals 13 and 14.

Here, one of the VHF oscillating circuit 24 and the UHF oscillating circuit 25 is activated by the switching signal output from the band switch 28, and the other is inactivated, so that the reception signal A frequency band is selected.

The intermediate frequency signals output to the terminals 13 and 14 are not required to be the intermediate frequency signal of the TV broadcasting channel to be selected, the intermediate frequency signal of the adjacent channel, the high frequency signal, or the local oscillation wave. Includes a signal. Therefore, an intermediate frequency filter (not shown) is provided outside the IC 41 to remove unnecessary signals contained in the intermediate frequency signal, and then input to the IC 41 from the terminals 11 and 12 again, and the intermediate frequency amplifier circuit 27 To increase and output from terminals 9 and 10.

The terminals 1, 3 and 4 to 7 are terminals for connecting the resonance circuit. The ground terminal 20 is a ground terminal of a high-frequency input circuit provided for the balanced-type input terminals 16 to 19. The other ground terminal 2 is a ground terminal that connects a ground line (not shown) laid inside the IC 41 to a ground line outside the IC 41.

[0008]

[Problems to be solved by the device]

 As described above, the IC 41 includes a plurality of high frequency circuits having different functions, and the frequencies of the signals handled by the respective high frequency circuits are different. Therefore, when the tuner is composed of disc parts, each circuit is housed in each compartment in a shield case whose interior is partitioned by electrically conductive partition walls. Prevents capacitive coupling and magnetic field coupling between them. However, when the tuner is composed of an IC, it is practically impossible to partition each circuit with conductive partition walls.

Therefore, conventionally, when designing the IC 41, the circuit arrangement on the IC pellet is devised so that the coupling between the circuits is made as small as possible, or each circuit is made a balanced type and connected by a balanced line. I was trying to solve it. However, the circuits had to be close to each other inside the IC, and the storage capacitance between the circuits was large, and the coupling between the circuits could not be made sufficiently small. In addition, it is difficult to realize an ideal balanced line, and under the present circumstances where the load of the intermediate frequency amplifier circuit is often designed as an unbalanced type, the influence of the unbalanced type load causes The equilibrium state of the circuit at the preceding stage collapsed, and it was easy to cause an obstructive coupling.

The most problematic coupling among the circuits is that the output lines of the VHF mixing circuit 42 and the UHF mixing circuit 43 are coupled to the input line of the intermediate frequency amplifier circuit 27 by the storage capacitance. If this coupling is large, the signal input to the intermediate frequency amplifier circuit 27 contains a large amount of unnecessary signals, and a large amount of unnecessary signals are output from the terminals 9 and 10, causing interference and beat interference. was there.

Therefore, an object of the present invention is to realize a tuner IC and a tuner IC chip with a simple configuration, which outputs few unnecessary signals and does not cause interference or beat failure. ..

[0012]

[Means for Solving the Problems]

 In the tuner IC according to the first invention, the output terminal of the frequency mixing circuit is arranged on one side and the input terminal of the intermediate frequency amplifying circuit is arranged on the other side of the ground terminal. ..

In the tuner IC chip according to the second invention, the ground line and the power supply are provided between the first region in which the frequency mixing circuit is provided and the second region in which the intermediate frequency amplifier circuit is provided. At least one of the tracks is laid.

[0014]

[Action]

 In the tuner IC, the output terminal of the frequency mixing circuit and the input terminal of the intermediate frequency amplifier circuit have capacitive coupling and magnetic field coupling reduced by the ground terminal provided therebetween, and the IC chip for the tuner is also provided. In the first area and the second area, the capacitive coupling and magnetic field coupling are reduced by the ground line or the power supply line laid between them.

[0015]

【Example】

 FIG. 1A shows a terminal arrangement of the IC 21 and a signal flow between main circuit blocks as an embodiment according to the first invention. In FIG. 1A, the circuit blocks having the same functions as the circuit blocks in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted. It should be noted that reference numerals 1 to 20 are terminal numbers assigned in the arrangement order of the terminals and do not correspond to the terminal numbers of the IC 41 shown in FIG. 2, but the description of the terminals not related to the present invention will be omitted. A more detailed circuit block is the same as that shown in FIG. 3 of Japanese Patent Laid-Open No. 3-216027 filed by the same applicant as this application.

In the tuner IC 21 shown in FIG. 1A, as described in Japanese Patent Laid-Open No. 3-216027, a frequency mixing circuit (hereinafter referred to as a mixing circuit) 26 has a VHF band. It is shared between the case of receiving the TV broadcast of and the case of receiving the UHF band TV broadcast. The intermediate frequency signal output from the mixing circuit 26 is output from the output terminals 6 and 7, and after unnecessary signals are removed by an intermediate frequency filter (not shown) provided outside the IC 21, the input terminal 3 , 4 again to be input to the IC 21, amplified by the intermediate frequency amplifier circuit 29, and output from the output terminals 1 and 2.

In the IC 21, the ground terminal 5 connects the ground line inside the IC 21 to the ground line outside the IC 21, and is provided between the output terminals 6 and 7 and the input terminals 3 and 4. Therefore, an electric field of O potential exists between the output terminals 6 and 7 and the input terminals 3 and 4, and direct capacitive coupling between the output terminals 6 and 7 and the input terminals 3 and 4 is prevented, Also, magnetic field coupling is reduced.

Next, FIG. 1B shows a main part of an IC chip 31 as one embodiment according to the second invention. Based on FIG. 1B, the tuner IC chip according to the second invention will be described. explain.

In FIG. 1B, reference numeral 31 is an IC chip, for example, a circuit is formed on a wafer of single crystal silicon. That is, 32 is a first region in which the mixing circuit 26 is formed, 33 is a second region in which the intermediate frequency amplifier circuit 27 is formed, and 34 is a third region in which other circuits are formed. Reference numerals 20 and 1 to 7 are bonding pads, which are connected to the terminals indicated by the same reference numerals of the IC 21 shown in FIG.

Reference numeral 35 denotes a ground line, a part of which is omitted, and one end of which is connected to a bonding pad 5 provided between the bonding pads 6 and 7 and the bonding pads 3 and 4, and which is a first region. It is laid between the second region 33 and the second region 33 and extends in the central portion of the IC chip 31. Reference numeral 36 is a power supply line shown with a part omitted, one end of which is connected to the bonding pad 20 and the other end of which is provided between the second region 33 and the third region 34.

The power supply line 36 is, as a conventional means, on the IC chip 31 and in an external circuit of the IC 21 via a large-capacity capacitor (not shown) having a sufficiently small impedance to an intermediate frequency signal. Since it is connected to the ground line 35, it functions similarly to the ground line 35 for intermediate frequency signals. Therefore, the first area 32 and the second area 33 may be separated by the power supply line 36.

[0022]

[Effect of the device]

 In the tuner IC 21, the output terminals 6 and 7 of the mixing circuit 26 and the input terminals 3 and 4 of the intermediate frequency amplifier circuit 27 are separated by the ground terminal 5, and the tuner IC chip 3 1 has an intermediate portion. Since the second region 33 provided with the frequency amplifier circuit 27 is separated from the first region 32 and the third region 34 by the ground line 35 or the power supply line 36, the capacitance between terminals and between circuits is reduced. Coupling is negligible in practice.

Therefore, according to the present invention, even if the circuit or the line is not in an ideal balanced state, an unnecessary signal is not output from the output terminals 1 and 2, and the tuner IC 21 or the tuner is not output. -If the receiver is configured using the IC chip 31 for the radio, it is possible to obtain the effect of not causing interference or bit failure.

[Brief description of drawings]

FIG. 1A is a configuration diagram showing an embodiment of a first device. (B) It is a principal part drawing which shows one Example of a 2nd invention.

FIG. 2 is a configuration diagram of a conventional tuner IC.

[Explanation of symbols]

 3,4 Input terminal 5 Ground terminal 6,7 Output terminal 21 Tuner IC 26 Frequency mixing circuit 27 Intermediate frequency amplification circuit 31 Tuner IC chip 32 First area 33 Second area 35 Ground line 36 Power Supply line

Claims (2)

[Scope of utility model registration request] 1. A tuner IC comprising: a frequency mixing circuit for outputting an intermediate frequency signal; and an intermediate frequency amplifying circuit configured to input the intermediate frequency signal passed through an intermediate frequency filter. An output terminal of the frequency mixing circuit is disposed on one side of the ground terminal connected to a ground line laid inside the tuner IC, and an input terminal of the intermediate frequency amplifier circuit on the other side. An IC for a tuner, characterized in that 2. A tubing characterized in that at least one of a ground line and a power supply line is laid between a first region provided with a frequency mixing circuit and a second region provided with an intermediate frequency amplifier circuit. IC chip for computer.