JPH11274971A - Transceiver - Google Patents

Abstract

(57) [Summary] To provide a low-cost transceiver equipped with a low-loss antenna switch. SOLUTION: In an integrated circuit 1, a receiving amplifier 2, a transmitting amplifier 4, a first switch 6 and a second switch 7 in a shunt configuration are configured. An antenna switch is formed by connecting the reactance element and the matching circuit 15 to the integrated circuit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver mainly used for a portable telephone, a pager, a teleterminal, or the like, and particularly to a transceiver in which a main part of a transmitting / receiving circuit is integrated.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a configuration of a conventional transceiver.

In FIG. 5, 2 is a receiving amplifier, 3 is a receiving circuit, 4 is a transmitting amplifier, 5 is a transmitting circuit, 8 is a first external terminal, 9 is a second external terminal, and 10 is a third external terminal. , 1
1 is a fourth external terminal, 14 is an antenna terminal, 15 is a matching circuit, 16 is an antenna, 101 is a first integrated circuit, 10
2 is a second integrated circuit, and 103 is a switch.

First, the operation of a conventional transmitting / receiving circuit will be described. The first and second integrated circuits 101 and 102 are monolithic ICs each having a circuit formed on a silicon substrate or the like.
C.

First, in a receiving operation, a received signal input to the antenna 16 is supplied to an antenna terminal 14 provided in the first integrated circuit 101. Further, the received signal is output from the first external terminal 8 via the switch 103. Here, the switch inserted between the antenna terminal 14 and the first external terminal 8 is arranged in series with the signal line and in shunt with respect to the ground, the switch in series arrangement is turned on, and the switch in shunt arrangement is turned off. ing.
On the other hand, the switches inserted between the antenna terminal 14 and the second external terminal 9 are similarly arranged in series and shunt, but the switches arranged in series are off and the switches arranged in shunt are on. Therefore, the impedance of the switch on the second external terminal 9 side from the antenna terminal 14 is high.

[0006] The received signal output from the first external terminal 8 is input to a third external terminal 10 provided in the second integrated circuit 102 via a matching circuit 15. The third external input terminal 10 is connected to an input of the receiving amplifier 2.
The matching circuit 15 is for matching the first external terminal 8 and the third external terminal 10. The output of the receiving amplifier 2 is input to the receiving circuit 3 and demodulated.

Next, in the transmission operation, the switches 103 are respectively switched. That is, the antenna terminal 14 and the first
The switches inserted between the external terminals 8 are turned off in the series arrangement and turned on in the shunt arrangement. As for the switch inserted between the antenna terminal 14 and the second external terminal 9, the switch arranged in series is turned on, and the switch arranged in shunt is turned off. Therefore, the impedance when the switch on the first external terminal 9 side from the antenna terminal 14 becomes high impedance.

The transmission signal from the transmission circuit 5 is transmitted to the transmission amplifier 4
The signal is amplified by the first external terminal 11 and output from the fourth external terminal 11, and is input to the second external terminal 9 via the matching circuit 15. Further, the light is output from the antenna terminal 14 via the switch 103 and is radiated to the space from the antenna 16.

The above is the operation of the conventional transceiver.

[0010]

However, the above-mentioned conventional transceiver has a problem that the loss of the antenna switch is increased. That is, although the switch is inserted in series with the signal line in FIG.
In a switch element (for example, a bipolar diode or an FET transistor) that can be realized by C or the like, insertion loss increases. For this reason, when a switch element is enlarged so as to cause a decrease in reception sensitivity or a decrease in transmission output or to reduce the loss, there is a problem that a chip size becomes large and a cost increases in a monolithic IC or the like.

In the conventional configuration, it is necessary to provide a matching circuit 15 between the antenna switch and the receiving amplifier and the transmitting amplifier. This is because a matching circuit cannot be inserted between the antenna switch and the antenna terminal because the off-side antenna switch needs to have high impedance when viewed from the antenna terminal. When the matching circuit is provided outside the integrated circuit, the number of terminals of the integrated circuit is increased as shown in FIG. 5, and at least five terminals are required. For this reason,
There is a problem that the cost of the package of the integrated circuit or the like increases. The reason why the matching circuit is provided outside the integrated circuit is that, for example, it is difficult to realize a good inductor element in a monolithic IC.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a low-cost, high-performance transceiver because the insertion loss of an antenna switch is small and the number of terminals of an integrated circuit can be reduced. I do.

[0013]

In a transceiver according to the present invention, a first external terminal connected to an input of a receiving amplifier, a second external terminal connected to an output of a transmitting amplifier, and a first and a second terminal having one end grounded. An integrated circuit having a second switch and third and fourth external terminals connected to the other ends of the first and second switches, respectively, is used, and one end of the first and second reactance elements is respectively connected to the third. And a fourth external terminal, and the other end is connected to an antenna terminal.

According to the above invention, since a switch arranged in series is not used and a reactance element outside the integrated circuit is used, the insertion loss of the antenna switch can be reduced, and the number of external terminals of the integrated circuit can be reduced. A low-cost transceiver with high performance can be realized.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A receiving amplifier, a first external terminal connected to an input of the receiving amplifier, a transmitting amplifier, a second external terminal connected to an output of the transmitting amplifier, and first and second terminals having one end grounded. And an integrated circuit having third and fourth external terminals connected to the other ends of the first and second switches, respectively, and first and second reactance elements and an antenna terminal. External terminal and third
Are connected, the second external terminal is connected to a fourth external terminal, and one ends of the first and second reactance elements are connected to third and fourth external terminals, respectively, The other ends of the first and second reactance elements are connected to the antenna terminal.
Since no switch element is inserted in the signal line in series, the insertion loss of the antenna switch can be reduced. Further, since the number of terminals of the integrated circuit can be reduced, a high-performance and low-cost transceiver can be realized.

Also, a receiving amplifier, a transmitting amplifier, first and second switches having one end grounded, an input of the receiving amplifier, a first external terminal connecting the other end of the first switch, and a transmitting amplifier. An integrated circuit including a second external terminal connected to an output and a third external terminal connected to the other end of the second switch; a first and a second reactance element and an antenna terminal; And the third external terminal are connected, and one ends of the first and second reactance elements are connected to the first and third external terminals, respectively, and the other ends of the first and second reactance elements are connected. Are connected to the antenna terminal.

Also, a receiving amplifier, a transmitting amplifier, first and second switches having one end grounded, an output of the transmitting amplifier, a first external terminal connecting the other end of the first switch, and a receiving amplifier. An integrated circuit having a second external terminal connected to an input and a third external terminal connected to the other end of the second switch; a first and a second reactance element and an antenna terminal; And the third external terminal are connected, and one ends of the first and second reactance elements are connected to the first and third external terminals, respectively, and the other ends of the first and second reactance elements are connected. Are connected to the antenna terminal.
Further, since the number of terminals of the integrated circuit can be further reduced, cost reduction can be achieved.

A first and a second switch, one end of which is grounded, a receiving amplifier, a transmitting amplifier, an input of the receiving amplifier, a first external terminal connected to the other end of the first switch, and a transmitting amplifier. An integrated circuit having an output and a second external terminal connected to the other end of the second switch; and an integrated circuit having first and second reactance elements and an antenna terminal; one end of the first and second reactance elements Are connected to first and second external terminals, respectively, and the other ends of the first and second reactance elements are connected to the antenna terminal. Further, the number of terminals of the integrated circuit can be further reduced.

The switch is constituted by an FET element. Since a low-loss switch can be configured on a monolithic IC, a high-performance transmission / reception circuit can be obtained at low cost.

[0020]

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

(Embodiment 1) FIG. 1 is a block diagram showing the configuration of an embodiment of a transceiver according to the present invention. In FIG. 1, 1 is an integrated circuit, 2 is a receiving amplifier, 3 is a receiving circuit,
Is a transmission amplifier, 5 is a transmission circuit, 6 is a first switch, 7
Denotes a second switch, 8 denotes a first external terminal, 9 denotes a second external terminal, 10 denotes a third external terminal, 11 denotes a fourth external terminal, 12 denotes a first inductor element, and 13 denotes a second inductor. , 14 is an antenna terminal, 15 is a matching circuit, 16
Is an antenna.

The integrated circuit 1 includes a receiving amplifier 2, a receiving circuit 3,
A transmission amplifier 4, a transmission circuit 5, and first, second, third, and fourth external terminals are configured. Here, the integrated circuit 1 may use a hybrid IC such as a pressure-film IC, but in the example shown here, a case of a monolithic IC formed on a semiconductor substrate will be described. Monolithic IC
Then, silicon, GaAs, or the like can be used as the semiconductor substrate. In addition, as a constituent element, each circuit can be formed by a bipolar transistor, a FET, or a mixture of the above in a Bi-CMOS process.

The reception signal input to the first external terminal 8 of the integrated circuit 1 is amplified by the reception amplifier 2 and input to the reception circuit 3 for demodulation. The transmission signal from the transmission circuit 5 is amplified by the transmission amplifier 4 and then output from the second external terminal 9. Here, an antenna switch is configured as follows to separate the reception signal and the transmission signal. One ends of the first and second switches 6 and 7 are grounded, and the other ends are third and fourth external terminals 1 and 2, respectively.
0 and 11 are connected. The first external terminal 8 and the third external terminal 10 are connected via a matching circuit 15.
Further, the second external terminal 9 and the fourth external terminal 11 are connected via a matching circuit 15. The third and fourth external terminals 10 and 11 are connected to the antenna terminal 14 via the first and second inductor elements 12 and 13, respectively. An antenna 16 is connected to the antenna terminal 14.

First, during the receiving operation, the first switch 6
Is set to OFF, and the second switch 7 is set to ON. At this time, the fourth external terminal 11 is short-circuited to the ground by the second switch 7 and the second inductor element 13 is connected to the fourth external terminal 11.
Of the external terminal 11 becomes high impedance. On the other hand, at this time, the first inductor element 12 and the matching circuit 15 are set so that the antenna terminal 14 matches the input impedance of the receiving amplifier 2.

Next, during the transmission operation, the first switch 6
Is set to ON, and the second switch 7 is set to OFF. At this time, the third external terminal 10 is short-circuited to ground by the first switch 6 and the first inductor element 12 is connected to the third external terminal 10.
Of the external terminal 10 becomes high impedance. At this time, the second inductor element 13 and the matching circuit 15 are set such that the antenna terminal 14 matches the output impedance of the transmission amplifier 4.

As described above, the second inductor element 13 functions as a high-impedance element during reception and the first inductor element 12 functions as a high-impedance element during transmission, whereby an operation as an antenna switch can be realized. . Since matching circuits can be configured independently on the receiving side and the transmitting side, matching can be achieved with respect to any impedance of the input of the receiving amplifier and the output of the transmitting amplifier.

Here, since the first and second inductor elements 12 and 13 are provided outside the integrated circuit, low-loss components such as air-core coils can be used, and the matching circuit similarly has a low-loss inductor element. And components such as a capacitor element can be used, and the insertion loss can be greatly reduced. Although the first and second switches 6 and 7 are arranged shunt with respect to the ground, the shunt arrangement has a relatively small effect on insertion loss as compared with a case where the switches are inserted in series with a signal line. That is, in this embodiment, it can be said that omitting the switches arranged in series with the signal lines is effective in reducing the insertion loss.

Further, in this embodiment, a circuit around the antenna switch can be constituted by four terminals in the integrated circuit 1. As described above, the number of terminals of the integrated circuit can be reduced, so that the cost of the package of the integrated circuit and the like can be reduced.

In this embodiment, the first and second inductor elements 12 and 13 are used as reactance elements. However, the same effect can be obtained by using a capacitor element.

Further, by using an FET transistor element as a switch element, a low-loss antenna switch can be realized. For example, MOS-FET or M
Since the ES-FET has a smaller on-resistance than a bipolar transistor or the like, the impedance at the time of the on-state becomes smaller, the isolation characteristics of the antenna switch can be improved, and the insertion loss on the passing side can be reduced.

(Embodiment 2) FIG. 2 is a block diagram showing the configuration of a transceiver according to Embodiment 2 of the present invention. In FIG. 2, reference numeral 17 denotes a capacitor. The same components as those in FIG. 1 are denoted by the same reference numerals. The features of this embodiment are as follows.
The point is that the number of terminals of the integrated circuit is reduced to three terminals. The configuration on the transmitting side is the same as that of the first embodiment, but the configuration on the receiving side is different. One end of the first switch 6 is grounded, and the other end is connected to the first external terminal 8 together with the input of the receiving amplifier 2. As described below, also in the configuration of the present embodiment, it is possible to match both reception and transmission.

First, during the receiving operation, the first switch 6 is turned off and the second switch 7 is turned on. At this time, the impedance when the third external terminal 10 side is viewed from the antenna terminal 14 becomes high impedance. On the other hand, at this time, the first inductor element 12 and the capacitor 17 are configured so that the antenna terminal 14 matches the input impedance of the receiving amplifier 2. Here, matching is performed with the first external terminal 8.
Alternatively, this can be performed by connecting a capacitor 17 or an inductor to the antenna terminal 14 in a shunt with respect to the ground. Further, a capacitor element may be used instead of the first inductor element 12 depending on the input impedance of the receiving amplifier 2. Also in this case, capacitors and inductors can be used as components connected to the shunt. In this way, circuit constants are set so that impedance matching can be achieved during reception.

Next, during the transmission operation, the first switch 6 is turned on and the second switch 7 is turned off. At this time,
Since the circuit constant connected to the first external terminal 8 in a shunt is short-circuited by the first switch 6, the impedance when the first external terminal 8 side is viewed from the first antenna terminal 14 is high. A matching circuit 15 is configured so that the output impedance of the transmission amplifier 4 matches the antenna terminal 14. Here, a capacitor 17 and the like are connected to the antenna terminal 14, and a matching circuit 15 is configured so as to match the antenna terminal 14 including the second inductor element 13. Since any circuit can be used as the matching circuit 15, a circuit that matches the output impedance of any transmission amplifier can be set. In the present embodiment, since the number of terminals of the integrated circuit 1 can be reduced, a lower-cost integrated circuit can be realized, and a low-cost transceiver can be obtained.

(Embodiment 3) FIG. 3 is a block diagram showing the configuration of a transceiver according to Embodiment 3 of the present invention. In FIG.
1 and 2 are denoted by the same reference numerals.

In this embodiment, the matching circuit 15 is provided on the receiving side. The number of terminals is three as in the second embodiment. The configuration according to the present embodiment has advantages such as simplification of the matching circuit or suppression of the loss of the matching circuit by the input impedance of the receiving amplifier 2 and the output impedance of the transmitting amplifier 4.

For example, when a circuit such as a filter is to be inserted before the receiving amplifier 2, the configuration of the present embodiment allows the matching circuit 15 provided on the receiving side to have filter characteristics. . Conversely, in the case of the second embodiment, there is a restriction on the circuit configuration in order to provide the receiving side with filter characteristics.

Therefore, the configuration of the second embodiment or the third embodiment can be selectively used depending on the case.

(Embodiment 4) FIG. 4 is a block diagram showing the configuration of a transceiver according to Embodiment 4 of the present invention. 4, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals. The feature of this embodiment is that the number of terminals of the integrated circuit is further reduced to two terminals.

At the time of reception, each constant of the second inductor element 13 and the capacitor 17 is set so that the impedance when the second external terminal 9 side is viewed from the antenna terminal 14 becomes high impedance.
The respective constants of the first inductor element 12 and the capacitor 17 may be set so that the impedance when the first external terminal 8 side is viewed from 4 becomes high impedance. However, in the present embodiment, since matching circuits cannot be independently designed for transmission and reception, it may be difficult to design a circuit that satisfies both matching for any impedance of the reception amplifier and the transmission amplifier. In this case, at the time of reception, the second external terminal 9 is connected to the antenna terminal 14.
The matching of the receiving side including the impedance looking at the side is taken,
At the time of transmission, the first external terminal 8 is connected to the antenna terminal 14.
By designing each constant so that matching on the transmitting side can be achieved, including the impedance seen from the side, matching can be achieved in sending and receiving. That is, the first and second inductor elements 12, 1
It is not always necessary to set the constant of 3 to be high impedance.

In the configuration of this embodiment, the number of terminals of the integrated circuit is further reduced, so that a transceiver with lower cost can be obtained.

In the first, second, and third embodiments, the constants of the first and second inductor elements do not necessarily need to be set to have high impedance. A transceiver can be configured by setting constants so as to achieve matching between transmission and reception including the first and second inductors.

[0042]

As is apparent from the above description, the following effects can be obtained according to the transceiver of the present invention.

Since the switch element arranged in series with the signal line can be omitted and low-loss components such as air-core coils can be used, the insertion loss of the antenna switch can be greatly reduced. Further, since the number of terminals of the integrated circuit can be reduced, the cost of a package or the like of the integrated circuit can be reduced.

Further, since the number of terminals for connecting the matching circuit on the receiving side or the transmitting side is reduced, a low-cost integrated circuit can be realized, and a low-cost transceiver can be obtained.

Further, since the FET transistor element is used as the switch element, the isolation characteristics of the antenna switch can be improved, and the insertion loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transceiver according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a transceiver according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a transceiver according to a third embodiment of the present invention.

FIG. 4 is a block diagram of a transceiver according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a conventional transceiver.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 integrated circuit 2 reception amplifier 3 reception circuit 4 transmission amplifier 5 transmission circuit 6 first switch 7 second switch 8 first external terminal 9 second external terminal 10 third external terminal 11 fourth external terminal 12 First inductor element 13 Second inductor element 14 Antenna terminal 15 Matching circuit 16 Antenna 17 Capacitor

Claims (5)

[Claims] 1. A receiving amplifier, a first external terminal connected to an input of the receiving amplifier, a transmitting amplifier, a second external terminal connected to an output of the transmitting amplifier, and a first terminal grounded at one end.
And an integrated circuit having a third switch and a third external terminal to which the other ends of the first and second switches are respectively connected, a first and a second reactance element, and an antenna terminal; The first external terminal and the third external terminal;
Are connected to the second external terminal and the fourth external terminal.
Are connected, one ends of the first and second reactance elements are connected to the third and fourth external terminals, respectively, and the other ends of the first and second reactance elements are connected to the antenna terminal. Connected transceiver. 2. A receiving amplifier, a transmitting amplifier, first and second switches each having one end grounded, an input of the receiving amplifier, a first external terminal connecting the other end of the first switch, and a transmitting amplifier. An integrated circuit including a second external terminal connected to an output and a third external terminal connected to the other end of the second switch; a first and a second reactance element and an antenna terminal; Are connected to the third external terminal, and one ends of the first and second reactance elements are connected to the first and third external terminals, respectively, and the first and second reactance elements are connected to each other. A transceiver having the other end connected to the antenna terminal. 3. A receiving amplifier, a transmitting amplifier, first and second switches having one end grounded, an output of the transmitting amplifier, a first external terminal connecting the other end of the first switch, and a receiving amplifier. An integrated circuit having a second external terminal connected to an input and a third external terminal connected to the other end of the second switch; a first and a second reactance element and an antenna terminal; Are connected to the third external terminal, and one ends of the first and second reactance elements are connected to the first and third external terminals, respectively, and the first and second reactance elements are connected to each other. A transceiver having the other end connected to the antenna terminal. 4. A receiving amplifier, a transmitting amplifier, first and second switches each having one end grounded, an input of the receiving amplifier, a first external terminal connecting the other end of the first switch, and a transmitting amplifier. An integrated circuit having an output and a second external terminal connected to the other end of the second switch; a first and a second reactance element and an antenna terminal;
And a transceiver having one end of the second reactance element connected to first and second external terminals, respectively, and the other end of the first and second reactance elements connected to the antenna terminal. 5. The transceiver according to claim 1, wherein the switch is constituted by an FET element.