JPH04172716A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To improve the signal characteristic and to reduce the cost by selecting an input buffer having a frequency band of a signal to be frequency- divided, frequency-dividing the inputted signal, forming an output buffer to be outputted on a same semiconductor substrate so as to attain frequency division over a broad band. CONSTITUTION:Input buffers 12-14 for high, medium and low frequency application respectively, 1st and 2nd selection circuits 18, 19, frequency dividers 15-17, an expanded frequency divider 20 and an output buffer 21 are formed on a semiconductor substrate 11. Thus, frequency-division over a broad band is attained by one prescaler semiconductor integrated circuit device, number of components is reduced and the cost is reduced.

Description

[Detailed Description of the Invention] [Summary] Regarding a prescaler semiconductor integrated circuit device that divides the frequency of a signal in a cotuner and outputs it to a PLL synthesizer, one semiconductor integrated circuit device can perform frequency division operation over a wide band, and The aim is to improve characteristics and reduce costs, as well as to reduce the area of the printed circuit board and make it more compact and lightweight. A first selection circuit that selects an input buffer having a frequency band of a signal to be divided and inputs a signal to the selected input buffer, and a plurality of frequency dividers that divides the frequency of the input signal from the corresponding input buffer. and a second selection circuit that selects a frequency divider corresponding to the input buffer selected by the first selection circuit and outputs a frequency-divided signal of the selected frequency divider; One extended frequency divider that divides the frequency of an output signal and one output buffer that outputs the frequency-divided signal of the extended frequency divider are formed on the same semiconductor substrate.

[Industrial Application Field] The present invention relates to a semiconductor integrated circuit device, and more specifically, for example, in a tuner, the frequency of a signal is divided and P L L (
The present invention relates to a prescaler semiconductor integrated circuit device that outputs to a synthesizer (Phase Locked Loop).

2. Description of the Related Art As wireless communication has become more sophisticated and complex in recent years, communication has come to be carried out over a very wide band, and tuners are required to be small, lightweight, and inexpensive. For this reason, it is desired that one prescaler semiconductor integrated circuit device be capable of frequency division operation over a wide band, and be small, lightweight, and inexpensive.

[Prior art] In a conventional wideband tuner, as shown in Fig. 3, a prescaler 1 is used for each of high frequency, medium frequency, and low frequency.
3, a selection circuit 4 that selects a prescaler having the frequency band of the input signal to be divided, and a selection circuit 5 that selects a frequency-divided signal from the selected prescaler and outputs it to a PLL synthesizer (path shown). A wideband frequency divider circuit device is used, which includes a power save circuit 6 that stops the operation of prescalers that are not in use, and a power save circuit 6 that is mounted on a printed circuit board (the circuit shown in the figure). Only prescalers with frequency bands are selected.

Each of the prescalers 1 to 3 is a separate semiconductor integrated circuit, and as shown in FIG. an extended frequency divider 9 that divides the frequency-divided signal of the frequency divider 8;
and an output buffer I that outputs the frequency-divided signal of the extended frequency divider 9.
0 on the same semiconductor substrate (the path shown in the figure).

Furthermore, each of the prescalers 1 to 3 can perform a 2-modulus operation by inputting a control signal from the outside to the frequency divider 8 and by inputting an output signal from the extended frequency divider 9. There is.

[Problems to be Solved by the Invention] However, in the conventional broadband tuner described above, each of the prescalers 1 to 3, the selection circuits 4 and 5, and the power save circuit 6 are separate semiconductor devices, and the number of components is large. There is a problem in that the cost is high.

Furthermore, as the number of components increases and the frequency band to be divided becomes wider, the number of prescalers mounted on the printed circuit board increases, resulting in an increase in the area of the printed circuit board and an increase in the size of the tuner. The fact that the selection circuits 4 and 5 and the power save circuit 6 are provided externally also causes an increase in the area of the printed circuit board.

Furthermore, since the selection circuits 4 and 5 are externally connected to each of the prescalers 1 to 3, there is also the problem that signal characteristics deteriorate due to stray capacitance, inductance, and the like.

The present invention has been made to solve the above-mentioned problems, and it is possible to perform frequency division operation over a wide band with one semiconductor integrated circuit device, improve signal characteristics and reduce costs. The purpose is to reduce the area of the printed circuit board, thereby making it smaller and lighter.

[Means for Solving the Problem] In order to achieve the above object, a first invention provides a plurality of input buffers into which signals of different frequency bands are input, and a frequency of a signal to be divided among the plurality of input buffers. a first selection circuit that selects an input buffer with a bandwidth and inputs a signal to the selected input buffer; and a first selection circuit that is provided corresponding to each input buffer sofa and divides the signal that is input through the corresponding input buffer. a second selection circuit that selects a frequency divider corresponding to the input buffer selected by the first selection circuit and outputs a frequency-divided signal of the selected frequency divider; , one extended frequency divider that frequency-divides the output signal of the second selection circuit, and one output buffer that outputs the frequency-divided signal of the extended frequency divider are formed on the same semiconductor substrate.

Further, the second invention makes it possible to drive only the input buffer having the frequency band of the signal to be divided and the frequency divider corresponding to the input buffer, and disables driving of other input buffers and frequency dividers. A power save circuit is formed on the semiconductor substrate.

Further, the third invention provides a plurality of input buffers into which signals of different frequency bands are input, and an input buffer having a frequency band of a signal to be divided from among the plurality of input buffers, and the selected input buffer. a first selection circuit that inputs a signal to the input buffer; a plurality of frequency dividers that are provided corresponding to each input buffer and divide the frequency of the signal input via the corresponding input buffer; selecting a plurality of extended frequency dividers that are provided as a frequency divider and divide the frequency of the divided signal of the corresponding frequency divider, and an extended frequency divider that corresponds to the input buffer selected by the first selection circuit; A third selection circuit that outputs the frequency-divided signal of the selected extended frequency divider and one output buffer that outputs the output signal of the third selection circuit are formed on the same semiconductor substrate.

Furthermore, the fourth invention makes it possible to drive only an input buffer having a frequency band of a signal to be divided, a frequency divider corresponding to the input buffer, and an extended frequency divider corresponding to the frequency divider, A power save circuit that makes the other input buffers, frequency dividers, and expansion dividers inoperable is formed on the semiconductor substrate.

[Operation] In the first invention, the input buffer having the frequency band of the signal to be divided is selected by the first selection circuit, and the frequency divider corresponding to the input buffer selects the input buffer that has the frequency band of the signal to be divided. is divided. Then, the second selection circuit selects that frequency divider and outputs a frequency-divided signal, and after this frequency-divided signal is frequency-divided by the extended frequency divider, it is output from the output buffer. Therefore, a single semiconductor integrated circuit device can perform frequency division operations over a wide band, and the cost can be reduced by increasing the degree of integration and reducing the number of parts.
．． Since the second selection circuit is provided on the same semiconductor substrate, signal characteristics are improved.

Furthermore, the reduced number of parts allows the area of the printed circuit board to be reduced, making the tuner smaller and lighter.

Further, in the third invention, although the semiconductor integrated circuit device is larger than the first invention, since an extended frequency divider is provided for each band, it is possible to set the frequency division ratio according to the band. Become.

Furthermore, the second. In the fourth invention, since the power save circuit is formed on the same semiconductor substrate, the degree of integration is further improved and the area of the printed circuit board is further reduced.

[Example] An example embodying the present invention will be described below with reference to FIG.

FIG. 1 shows an embodiment embodying the first and second inventions.

On the semiconductor substrate 11 are input buffers 12 to 14 for high frequency, medium frequency, and low frequency; Second selection circuit 18,1
9. Frequency divider 1 corresponding to each of the input buffers 12 to 14
5 to 17. One extended frequency divider 20, one output buffer 21, and a power save circuit 22 are formed. A selection signal is inputted to the first and second selection circuits 1.8.19 and the power save circuit 22 from the outside.

Based on the selection signal, the power save circuit 22 makes it possible to drive only the input buffer having the frequency band of the input signal to be divided and its corresponding frequency divider, and cannot drive other input buffers and frequency dividers. This makes it possible to reduce power consumption.

The first selection circuit 18 selects an input buffer having a frequency band of the input signal to be divided based on the selection signal,
Input the signal into the selected input huffer. The selected input buffer outputs a signal to a corresponding frequency divider, and the frequency divider divides the signal by a predetermined frequency division ratio. A second selection circuit 19 selects a frequency divider corresponding to the input buffer selected by the first selection circuit 18 based on the selection signal and outputs a frequency divided signal of the selected frequency divider. do.

The extended frequency divider 20 divides the frequency of the output signal of the second selection circuit 19, and the output buffer 21 outputs the frequency divided signal of the extended frequency divider 20 to a PLL synthesizer (not shown).

As described above, in this embodiment, the input buffers 12 to 14 for high frequency, medium frequency, and low frequency, the first . Second selection circuit 18
, 19, since the frequency dividers 15 to 17, the extended frequency divider 20, and the output buffer 21 are formed on the semiconductor substrate 11, frequency division operation over a wide band can be performed with one prescaler semiconductor integrated circuit device. Compared to the conventional wideband frequency divider circuit device shown in FIG. Further, by reducing the number of parts, the area of the printed circuit board can be reduced, and the tuner can be made smaller and lighter.

In addition, in this embodiment, the first. Since the second selection circuits 18 and 19 are formed on the same semiconductor substrate 11, there is almost no influence of stray capacitance, inductance, etc., and signal characteristics can be improved.

Furthermore, in this embodiment, since the power save circuit 22 is formed on the same semiconductor substrate 11, the degree of integration can be further improved and the area of the printed circuit board can be made smaller, making it possible to make the tuner smaller and lighter. .

Incidentally, by inputting a control signal from the outside to each of the frequency dividers 15 to 17 and also inputting the output signal of the extended frequency divider 20, the 2-modulus operation may be performed.

[Another Embodiment] Next, an embodiment embodying the third and fourth inventions will be described with reference to FIG. 2.

For convenience of explanation, the same components as in FIG. 1 are designated by the same reference numerals and the explanation thereof will be omitted.

In this embodiment, expansion frequency dividers 23 to 25 correspond to high frequency, medium frequency, and low frequency input buffers 12 to 14, respectively.
is formed. A third selection circuit 26 formed at the next stage of these extended frequency dividers 23 to 25 selects the extended frequency divider corresponding to the input buffer selected by the first selection circuit 18 and selects the extended frequency divider. The frequency-divided signal of the extended frequency divider is output to the output buffer 21. Further, the power save circuit 27 can drive only the input cover, the sofa, the corresponding frequency divider, and the extended frequency divider having the frequency band of the input signal to be divided based on the selection signal, and can drive only the input cover and the sofa having the frequency band of the input signal to be divided. The input buffer and its corresponding frequency divider and extended frequency divider are rendered inoperable.

In this way, in this embodiment, the extended frequency dividers 23 to 25 are formed corresponding to each input buffer 12 to 14, and therefore, an extended frequency divider is provided for each band. You can set the division ratio. Also, each input buffer 1
By forming extended frequency dividers 23 to 25 corresponding to 2 to 14, the prescaler semiconductor integrated circuit device becomes larger compared to the first invention, but the conventional wideband frequency divider circuit shown in FIG. The degree of integration is higher than that of other devices, and it is possible to reduce the cost of the semiconductor integrated circuit device and to make the tuner smaller and lighter.

Also, in this embodiment, since the power save circuit 27 is formed on the same semiconductor substrate 11, the degree of integration can be further improved and the area of the printed circuit board can be made smaller, thereby making the tuner smaller and lighter. can.

[Effects of the Invention] As detailed above, according to the first invention, one semiconductor integrated circuit device can perform frequency division operation over a wide band,
Signal characteristics can be improved and costs can be reduced, and the area of the printed circuit board can be reduced to reduce size and weight.

According to the third invention, since an extended frequency divider is provided for each band, in addition to the effects of the first invention, it is possible to set a frequency division ratio according to the band.

Second. According to the fourth invention, since the power save circuit is formed on the same semiconductor substrate, the degree of integration can be further improved and the area of the printed circuit board can be made smaller, making it possible to make the tuner smaller and lighter. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment, Fig. 2 is a block diagram showing another embodiment, Fig. 3 is a block diagram showing a conventional wideband frequency dividing circuit device, and Fig. 4 is a block diagram showing a prescaler. It is a diagram. In the figure, 11 is a semiconductor substrate, 12 to 14 are input buffers, 15 to 1.7 are frequency dividers, 18 is a first selection circuit, 19 is a second selection circuit, 20. 23 to 25 are extended frequency dividers 21 is an output buffer, 22.27 is a power save circuit, and 26 is a third selection circuit.

Claims (1)

[Claims] 1. A plurality of input buffers (12 to 14) into which signals of different frequency bands are input, and an input having the frequency band of the signal to be divided among the plurality of input buffers (12 to 14). a first selection circuit that selects a buffer and inputs a signal to the selected input buffer;
18), a plurality of frequency dividers (15 to 17) provided corresponding to each input buffer (12 to 14) and dividing the frequency of a signal inputted via the corresponding input buffer;
a second selection circuit (19) that selects a frequency divider corresponding to the input buffer selected by the selection circuit (18) and outputs a frequency-divided signal of the selected frequency divider; One extended frequency divider (20) that divides the output signal of the circuit (19) and one output buffer (21) that outputs the divided signal of the extended frequency divider (20) are mounted on the same semiconductor substrate. A semiconductor integrated circuit device characterized in that: 2. A power save circuit (22) that enables driving only the input buffer that has the frequency band of the signal to be divided and the frequency divider corresponding to the input buffer, and disables driving other input buffers and frequency dividers. 2. The semiconductor integrated circuit device according to claim 1, further comprising: formed on said semiconductor substrate. 3. Select the input buffer that has the frequency band of the signal to be divided among the multiple input buffers (12 to 14) that input signals of different frequency bands, and the input buffer that has the frequency band of the signal to be divided. A first selection circuit that inputs a signal to the selected input buffer (
18), a plurality of frequency dividers (15 to 17) provided corresponding to each input buffer (12 to 14) and dividing the frequency of a signal inputted via the corresponding input buffer, and each frequency divider A plurality of extended frequency dividers (23 to 25) that are provided corresponding to (15 to 17) and divide the frequency of the divided signal of the corresponding frequency divider.
and a third selection circuit (26) that selects an extended frequency divider corresponding to the input buffer selected by the first selection circuit (18) and outputs a divided signal of the selected extended frequency divider. ) and one output buffer (21) for outputting the output signal of the third selection circuit (26) are formed on the same semiconductor substrate. 4. Only the input buffer that has the frequency band of the signal to be divided, the frequency divider corresponding to that input buffer, and the extended frequency divider corresponding to that frequency divider can be driven, and other input buffers and 4. The semiconductor integrated circuit device according to claim 3, further comprising a power save circuit (27) formed on the semiconductor substrate to make the frequency divider and the extended frequency divider inoperable.