JP2007158973A - Mobile communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile communication terminal including a high-frequency switch circuit comprised of an antenna switch that is small-sized and reduces a passing loss, demultiplexer circuits and a detection circuit. <P>SOLUTION: The present invention relates to multiband equipment for performing transmission power control, wherein a high-frequency switch circuit 4-1 comprised of an antenna switch 4a for switching a plurality of antenna units 1, 2, 3, a demultiplexer circuit 4b, 4c provided for each frequency band to realize a directional coupler and a detection circuit 4d for detecting demultiplexed transmission power is comprised of a semiconductor integrated circuit as one hybrid component. Thus, within the high-frequency switch circuit 4-1 comprised of one semiconductor integrated circuit, the antenna switch 4a changes over frequency bands in accordance with a minimum component constant decreasing a compensation circuit, the demultiplexer circuit 4b, 4c demultiplexes transmission power for each frequency band and the detection circuit 4 detects the demultiplexed transmission power, thereby performing transmission power control. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mobile communication terminal that performs transmission power control, and more particularly to a multiband mobile communication terminal that transmits and receives power in a plurality of frequency bands from a plurality of antennas.

  Conventionally, in a mobile communication terminal, transmission power is demultiplexed by a demultiplexing circuit immediately after a high-frequency amplifier, and the demultiplexed transmission power is input to a detection circuit to detect a detection voltage. Control is realized. Furthermore, in order to accurately detect the transmission power, a directional coupler or isolator is used to prevent propagation of a reflected wave of the transmission power generated by the antenna. In addition, since the detection method of the transmission power in such a mobile communication terminal is a widely known technique, the description thereof is omitted.

In addition, a multiband mobile communication terminal having a plurality of frequency bands (such a mobile communication terminal is called a multiband device) uses a plurality of antennas to transmit and receive radio waves to and from the base station apparatus. As a result, diversity transmission / reception for improving the reception characteristics of the mobile communication terminal is performed. However, in these multiband devices, a demultiplexing circuit and a detection circuit are used for each frequency band to be transmitted / received, or a separate demultiplexing circuit is provided for each frequency band so that only the detection circuit is shared. However, in such a configuration, the number of parts increases, resulting in an increase in the surface area and volume of the mobile communication terminal. Therefore, by combining a demultiplexing circuit, a detection circuit, an antenna switch, and the like before the antenna regardless of the frequency band, the high-frequency switch circuit is hybridized as a composite component, and the mobile communication terminal is downsized. (For example, refer to Patent Document 1).
JP 2001-274723 A

  However, in the transmission power detection method by the conventional mobile communication terminal described above, in order to perform demultiplexing and detection immediately after the high frequency amplifier, the circuit before the high frequency amplifier and to the antenna includes an isolator, a filter, And there are many parts such as switches. Therefore, even if the transmission power is in the same frequency band, the frequency deviation becomes large due to the constant variation of these many components. Therefore, a compensation circuit for compensating for the frequency deviation is required. In addition, in order to perform accurate transmission power control due to the temperature characteristics of each component differing even with temperature changes, a compensation circuit that uses correction data such as frequency correction and temperature correction in addition to the transmission power detection circuit Is required. Therefore, the number of circuit components further increases, and the mobile communication terminal becomes large.

  In addition, in the detection method using the demultiplexing circuit and the detection circuit for each frequency band like the multiband device of the mobile communication terminal described above, the number of parts increases because the same number of circuits as the frequency band is required. The volume and surface area of the mobile communication terminal will increase. Furthermore, the detection method that installs a demultiplexing circuit for each frequency band and uses only the detection circuit reduces the number of parts, volume, and surface area slightly, but the influence of radio waves from the frequency band that is not used at that time As a result, the demultiplexed power increases and the transmission power loss increases. In addition, since individual signal lines in each frequency band are wired to one common detection circuit, the degree of freedom of board arrangement is lost. In the technique of Patent Document 1 described above, since the hybrid high frequency switch circuit is provided at the front stage of the antenna, it is necessary to provide a high frequency switch circuit in the antenna for each frequency band. As the number of points increases, miniaturization of the mobile communication terminal is not realized.

  The present invention has been made in view of such a point, and by reducing the number of components by reducing the compensation circuit by making the antenna switch for switching a plurality of antennas, the demultiplexing circuit, and the detection circuit into one hybrid component. And it aims at providing the mobile communication terminal which can improve the freedom degree of board | substrate arrangement | positioning.

  The mobile communication terminal of the present invention is a multiband mobile communication terminal in which a high frequency switch circuit switches and controls transmission power in a plurality of frequency bands, and the high frequency switch circuit transmits and receives radio waves having different frequency bands. An antenna switch for switching the antenna, a demultiplexing circuit provided in each frequency band for controlling transmission power, and realizing a directional coupler for demultiplexing the transmission power, and a demultiplexing circuit And a detection circuit for detecting the transmission power demultiplexed in (1), and the high frequency switch circuit is realized by a semiconductor integrated circuit.

  That is, according to the present invention, a multiband mobile communication terminal that transmits and receives power in a plurality of frequency bands is provided in each frequency band to demultiplex transmission power in order to control transmission power. A high-frequency switch circuit composed of a directional coupler, a detection circuit that detects transmission power, and an antenna switch that switches antennas to switch frequency bands is realized by a hybrid semiconductor integrated circuit. . With such a configuration, the number of parts of the circuit constituting the mobile communication terminal is reduced, and since there are no parts from the high-frequency switch circuit to the antenna, frequency deviation and temperature deviation caused by part variation are reduced. Correction data can be reduced.

  Moreover, the mobile communication terminal of the present invention adopts a configuration in which, in the configuration of the present invention, the branching circuit realizes a directional coupler by a circuit configuration of only a capacitor. Thereby, the semiconductor integrated circuit constituting the high-frequency switch circuit can be further simplified.

  In the mobile communication terminal of the present invention, in the configuration of the invention, the high frequency switch circuit uses the switching control signal for switching the frequency band to be used, and the branch circuit corresponding to the unused frequency band is A configuration including a relay circuit that is separated from the detection circuit is employed. With such a configuration, power detection can be performed without being affected by a demultiplexing circuit in an unused frequency band, and thus it is possible to reduce the loss of demultiplexed power.

  In the mobile communication terminal of the present invention, in the configuration of the present invention, the relay circuit uses an ON / OFF control signal for performing ON / OFF control of power transmission, and demultiplexes except when performing power transmission. The circuit is disconnected from the detection circuit. With such a configuration, it is possible to reduce the passage loss of received power when power is not transmitted without being affected by an unused frequency band for power detection.

  Further, the mobile communication terminal of the present invention employs a configuration in which, in the configuration of the present invention, the relay circuit performs control so that the gain characteristic and noise characteristic of the low noise amplifier in the receiving circuit are in a high gain / low noise state. Yes. With such a configuration, the passing loss of the received power that is inevitably generated by using the branching circuit is controlled so that the reception sensitivity is not deteriorated by the overall characteristics at the time of reception, and as a result, the sensitivity is high. Reception can be performed.

  According to the mobile communication terminal of the present invention, the high-frequency switch circuit immediately following a plurality of antennas is made into a hybrid IC by a demultiplexing circuit, a detection circuit, an antenna switch, etc. Correction data such as frequency correction and temperature correction can be reduced. Furthermore, the increase in the number of parts of the demultiplexing circuit and the detection circuit for transmission power control generated with the multiband of the mobile communication terminal is suppressed, the circuit configuration of the mobile communication terminal is reduced, and the wiring is reduced. This makes it possible to reduce the size and weight of the device and reduce the cost. Furthermore, the passing loss of the received power that occurs due to the use of the demultiplexing circuit is controlled so that the gain characteristics and noise characteristics of the LNA (low noise amplifier) of the receiving circuit are in a high gain / low noise state, It is possible to control so that the reception sensitivity is not deteriorated by the overall characteristics at the time of reception.

<Summary of invention>
The mobile communication terminal of the present invention is a multiband mobile communication terminal that transmits and receives radio waves in a plurality of frequency bands using a plurality of antennas, an antenna switch that switches between the plurality of antennas, a transmission system signal, and a reception system signal A demultiplexing circuit for demultiplexing the separated power and a detection circuit for detecting the demultiplexed transmission power are made into a hybrid IC as one composite component. At this time, the branching circuit realizes a function as a directional coupler that prevents a reflected wave of transmission power generated by the antenna. Such a configuration eliminates the need for correction data for correcting frequency deviations, temperature deviations, and the like due to variations in component constants, eliminating the need for a compensation circuit and further reducing the number of components. In addition, since it is not necessary to wire individual signal lines in each frequency band to one common detection circuit, the degree of freedom of substrate placement can be further improved.

  Hereinafter, some of the embodiments of the mobile communication terminal according to the present invention will be described in detail with reference to the drawings. In the drawings used in the embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted as much as possible.

<Embodiment 1>
FIG. 1 is a circuit diagram of a mobile communication terminal according to Embodiment 1 of the present invention. The mobile communication terminal according to the first embodiment includes antenna units 1, 2, and 3 that transmit and receive signals, an antenna switch 4a that switches a use frequency of the antenna units 1, 2, and 3, and branching circuits 4b and 4c. And a high-frequency switch circuit 4-1 that detects transmission power in a switched frequency band, and a common circuit that suppresses interference waves in each frequency band. 5, 6, a transmission radio unit 7 that performs power control of the transmission system, a reception radio unit 8 that performs power control of the reception system, and a radio control unit 9 that performs overall control of the mobile communication terminal. It has become the composition.

  The transmission radio unit 7 also includes a transmission RF-IC (Tx-IC) 16 that can perform power supply setting and frequency setting by an IC control signal, transmission bandpass filters 14 and 15 that suppress interference waves, and output power. Power amplifiers 12 and 13, and isolators 10 and 11 for preventing transmission of reflected waves of transmission power generated by the antenna units 1, 2, and 3. Further, the reception radio unit 8 performs power supply setting and frequency setting with low noise amplifiers 17 and 18 for amplifying low noise signals, reception bandpass filters 19 and 20 for suppressing interference waves, and IC control signals. Receiving RF-IC (Rx-IC) 21.

  Next, the operation of the mobile communication terminal in Embodiment 1 shown in FIG. 1 will be described. However, the power control of the transmission system performed by the transmission radio unit 7 and the power control of the reception system performed by the reception radio unit 8 are well-known techniques, and thus description thereof will be omitted, and a portion of the high-frequency switch circuit 4-1 according to the present invention will be omitted. Only the operation will be described. When the antenna units 1, 2 and 3 transmit and receive signals of different band frequencies, in the high frequency switch circuit 4-1, the antenna switch 4a switches the antenna units 1, 2 and 3 to switch the band frequencies. Further, the detection circuit 4d detects the transmission power of the band frequency that passes through the directional coupler including the demultiplexing circuits 4b and 4c.

  When the transmission power in the frequency band in which the high frequency switch circuit 4-1 has been switched is detected in this way, the duplexer 5 suppresses the interference wave in the transmission / reception signal in the frequency band of the frequency A, and further, the transmission radio unit 7 controls the transmission signal in which the interference wave is suppressed, and the reception radio unit 8 controls the reception signal in which the interference wave is suppressed. Similarly, the duplexer 6 suppresses the interference wave for the transmission / reception signal in the frequency band of the frequency B, the transmission radio unit 7 controls the transmission signal in which the interference wave is suppressed, and the reception radio unit 8 receives the interference wave. The received signal is suppressed.

  The mobile communication terminal according to Embodiment 1 shown in FIG. 1 includes demultiplexing circuits 4b and 4c composed of directional couplers that demultiplex transmission power, a detection circuit 4d that detects transmission power, and antenna units 1 and 2. , 3 and the antenna switch 4a for switching the frequency band are integrally coupled to form a high-frequency switch circuit 4-1, thereby realizing a semiconductor integrated circuit using a hybrid IC. With the configuration of such a semiconductor integrated circuit, the number of circuit components of the mobile communication terminal is reduced, and there are no components in the parts from the high frequency switch circuit 4-1 to the antenna units 1, 2, 3. Since the frequency deviation and the temperature deviation due to the constant variation of are reduced, the correction data can be reduced.

  Note that the mobile communication terminal of the first embodiment can also configure a semiconductor integrated circuit with a circuit configuration that demultiplexes transmission power using only a capacitor instead of the directional coupler including the demultiplexing circuits 4b and 4c. . As a result, the high-frequency switch circuit 4-1 can be further simplified.

<Embodiment 2>
FIG. 2 is a circuit diagram of the mobile communication terminal according to Embodiment 2 of the present invention. The mobile communication terminal of the second embodiment shown in FIG. 2 is different from the mobile communication terminal of the first embodiment shown in FIG. 1 in that the configuration of the high-frequency switch circuit 4-1 in FIG. Then, it is the point which changed into the high frequency switch circuit 4-2 which added the relay circuit 4e for cut | disconnecting the connection of the frequency band which is not used.

  That is, the mobile communication terminal according to the second embodiment shown in FIG. 2 includes an antenna switch 4a that switches the operating frequencies of the antenna units 1, 2, and 3, a directional coupler that includes branching circuits 4b and 4c, A detection circuit 4d that detects transmission power and a relay circuit 4e that disconnects unused frequency bands, and includes a high-frequency switch circuit 4-2 that detects transmission power in the switched frequency band. The point is different from the mobile communication terminal of the first embodiment shown in FIG.

  The mobile communication terminal according to Embodiment 2 of the present invention includes a relay circuit 4e that disconnects an unused frequency band demultiplexing circuit (for example, 4c) from the detection circuit 4d using a switching control signal for switching frequency bands. Yes. According to such a configuration, by separating the demultiplexing circuit 4c in the unused frequency band, the detection circuit 4d can detect the transmission power without being affected by the unused demultiplexing circuit 4c. As a result, it is possible to further reduce the loss of the demultiplexed transmission power.

<Embodiment 3>
FIG. 3 is a circuit diagram of the mobile communication terminal according to Embodiment 3 of the present invention. The mobile communication terminal of the third embodiment shown in FIG. 3 is different from the mobile communication terminal of the second embodiment shown in FIG. 2 in that the configuration of the high-frequency switch circuit 4-2 in FIG. Then, when electric power is not transmitted to the transmission radio | wireless part 7, the relay circuit 4e is changed to the high frequency switch 4-3 comprised so that the connection to the transmission radio | wireless part 7 might be cut | disconnected.

  That is, the mobile communication terminal of the third embodiment shown in FIG. 3 includes an antenna switch 4a that switches the use frequency of the antenna units 1, 2, and 3, a directional coupler that includes branching circuits 4b and 4c, The detection circuit 4d that detects transmission power and the relay circuit 4e that disconnects the unused frequency band and disconnects the connection to the transmission radio unit 7 at the time of non-transmission. 2 is different from the mobile communication terminal according to the second embodiment shown in FIG. 2 in that a high-frequency switch circuit 4-3 is provided.

  In the mobile communication terminal according to Embodiment 3 of the present invention, the relay circuit 4e uses the ON / OFF control signal for performing ON / OFF control of power transmission, and the demultiplexing is performed except when power is transmitted to the transmission radio unit 7. The circuit 4b, 4c and the detection circuit 4d are disconnected. With such a configuration, when the detection circuit 4d performs power detection, it is not affected by an unused frequency band, and reduces the passage loss of the received signal when not transmitted to the transmission radio unit 7. Can do.

<Embodiment 4>
FIG. 4 is a circuit diagram of a mobile communication terminal according to Embodiment 4 of the present invention. The mobile communication terminal according to the fourth embodiment shown in FIG. 4 is different from the mobile communication terminal according to the third embodiment shown in FIG. 3 in that the low noise amplifiers 17 and 18 of the reception radio unit 8 include the high frequency switch circuit 4. 4 is provided with a function capable of switching the gain and noise characteristics to a high gain and low noise state by a control signal from -4.

  That is, in the mobile communication terminal according to Embodiment 4 of the present invention, reception radio section 8 can switch the gain and noise characteristics to a high gain and low noise state by a control signal from high frequency switch circuit 4-4. The low noise amplifiers 17 and 18 are different from the mobile communication terminal according to the third embodiment shown in FIG.

  In the mobile communication terminal according to the fourth embodiment of the present invention, when using the demultiplexing circuits 4b and 4c, the gain and noise characteristics of the LNA (low noise amplifier) of the receiving circuit are controlled so as to be in a high gain and low noise state. It has a function. With such a configuration, a high-sensitivity receiving apparatus is realized by controlling the reception loss caused by using the demultiplexing circuits 4b and 4c so that the reception sensitivity is not deteriorated by the overall characteristics of reception. can do.

<Summary>
As described above, in a multiband device that performs transmission power control in a conventional mobile communication terminal, a detection method for detecting transmission power using a demultiplexing circuit and a detection circuit for each frequency band, and a demultiplexing circuit are provided. A detection method is used in which only the detection circuit is installed in each frequency band. In such a detection method, the number of parts of the circuit increases, the surface area and volume of the mobile communication terminal increase, or the demultiplexed power increases due to the influence from the unused frequency band and the power loss increases. To do.

  Therefore, in the multiband device in the mobile communication terminal of the present invention, an antenna switch that switches the antenna of each frequency band, and a demultiplexing circuit that is provided in each frequency band to perform transmission power control and demultiplexes the transmission power A high-frequency switch circuit including a (directional coupler) and a detection circuit that detects the separated transmission power is configured as one semiconductor integrated circuit. At this time, the high frequency switch circuit has a function of disconnecting the demultiplexing circuit from the detection circuit when an unused frequency band or power is not transmitted. With such a configuration, it is possible to provide a mobile communication terminal including a high-frequency switch circuit having a small-sized demultiplexing circuit and a detection circuit with small passage loss.

  The mobile communication terminal according to the present invention can reduce correction data, reduce the number of components, and freely arrange components by combining a demultiplexing circuit, a detection circuit, and an antenna switch into one semiconductor component. Therefore, it can be effectively used as a high frequency switch IC for a mobile communication terminal.

Circuit diagram of mobile communication terminal according to Embodiment 1 of the present invention Circuit diagram of mobile communication terminal according to Embodiment 2 of the present invention Circuit diagram of mobile communication terminal according to Embodiment 3 of the present invention Circuit diagram of mobile communication terminal according to Embodiment 4 of the present invention

Explanation of symbols

1, 2, 3 Antenna section 4-1, 4-2, 4-3, 4-4 High frequency switch circuit 4a Antenna switch 4b, 4c Demultiplexing circuit 4d Detection circuit 4e Relay circuit 5,6 Duplexer 7 Transmitting radio section 8 Reception radio section 9 Radio control section 10, 11 Isolator 12, 13 Power amplifier 14, 15 Transmission bandpass filter 16 Transmission RF-IC (Tx-IC)
17, 18 Low noise amplifier 19, 20 Reception band pass filter 21 Reception RF-IC (Rx-IC)

Claims (5)

A high-frequency switch circuit is a multiband mobile communication terminal that switches and controls transmission power in a plurality of frequency bands,
The high-frequency switch circuit is
An antenna switch for switching a plurality of antennas for transmitting and receiving radio waves of different frequency bands;
A demultiplexing circuit provided in each frequency band for controlling the transmission power, and realizing a directional coupler for demultiplexing the transmission power;
A detection circuit for detecting transmission power demultiplexed by the demultiplexing circuit,
A mobile communication terminal characterized in that the high-frequency switch circuit is constituted by a semiconductor integrated circuit.   The mobile communication terminal apparatus according to claim 1, wherein the branching circuit realizes the directional coupler by a circuit configuration including only a capacitor.   2. The high-frequency switch circuit includes a relay circuit that separates a demultiplexing circuit corresponding to an unused frequency band from the detection circuit using a switching control signal for switching a frequency band to be used. Alternatively, the mobile communication terminal according to claim 2.   The relay circuit uses an ON / OFF control signal for ON / OFF control of power transmission, and disconnects the branching circuit and the detection circuit except when power transmission is performed. The mobile communication terminal according to claim 3.   5. The mobile communication terminal according to claim 4, wherein the relay circuit performs control such that a gain characteristic and a noise characteristic of a low noise amplifier in a receiving circuit are in a high gain / low noise state.

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