JP3647519B2 - GaAs integrated circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to gallium arsenide (GaAs) integrated circuits used in the transmitter unit or the like of the radio.
[0002]
[Prior art]
The next-generation cordless telephone (simple mobile phone: hereinafter referred to as PHS) has been changed from an analog transmission system to a digital transmission system, and the frequency used is increased from 0.4 GHz to 1.9 GHz. By changing to the digital system, a part such as a voice control among the parts constituting the telephone can be constituted by a digital circuit, so that the size can be reduced. On the other hand, since the radio use frequency is as high as 1.9 GHz, a field effect transistor (FET) using a GaAs element capable of high-frequency operation is used for a circuit for transmitting and receiving radio signals. In the case of this GaAsFET, since the forward voltage of the gate is as low as about 0.7 V, the voltage at which the FET current (drain current) is turned off by the gate voltage is set low as 0 V or less (about -2 V). . Therefore, in order to turn off the current of the GaAsFET, it is necessary to set the drain voltage to 0V or set the gate voltage to 0V or less. In order to obtain this voltage of 0 V or less, a circuit for generating a negative voltage is required in addition to the high-frequency integrated circuit composed of GaAsFET. When a power supply (drain current) is supplied to a transmission power amplifier (hereinafter referred to as HPA), it is necessary to give a desired negative voltage for controlling the HPA current in advance to the HPA gate voltage.
[0003]
FIG. 9 is a circuit diagram showing a configuration of a circuit of a conventional transmission / reception unit. In the conventional circuit configuration, each function is composed of individual elements. In the figure, 1 is a transmission power amplifier (HPA) made of GaAs IC, 2 is a negative voltage generating circuit, 3 is an antenna changeover switch (hereinafter referred to as SW), 4 is a low noise amplifier for reception (hereinafter referred to as LNA), 5 Is a power switch for HPA 1, 6 is a power switch for LNA 4, 7 is a control LSI made of SiIC, and 8 is an antenna.
In PHS, since transmission and reception differ from time to time, the power switch 5 of the HPA 1 is turned on and the SW 3 is switched to the transmission side during signal transmission time. A signal to be transmitted is amplified by the HPA 1 and transmitted from the antenna 8 through the SW 3. When receiving a signal, SW3 is switched to the receiving side. A reception signal from the antenna 8 flows to the reception circuit side by SW3, is amplified by the LNA 4, and is received as a reception signal. This signal is demodulated and then converted into an audio signal that can be heard through a speaker.
[0004]
A cordless telephone is desired to be small and lightweight so that it can be easily carried, and it is desired to reduce the number of parts in order to cope with this. That is, integration of functions is advanced, and development of integrated ICs of high-frequency circuits such as HPA1, SW3, and LNA4 is underway. Further, integration of the negative voltage generation circuit 2 with a high-frequency circuit has been studied for integration of functions.
[0005]
[Problems to be solved by the invention]
In a conventional cordless telephone (PHS) having a circuit configuration as described above, a reduction in the number of components or a high integration of functions are required for further miniaturization and weight reduction . Similarly to the high frequency circuit unit, to constitute a negative voltage generating circuit 2 on a GaAs device, there is a problem that the current consumption compared to CMOSIC of Si increases.
[0006]
The present invention has been made to solve the above problems, reducing the PHS number of parts, functions as well as high integration, and an object thereof is to reduce the current consumption.
[ 0007 ]
[Means for Solving the Problems]
The GaAs integrated circuit according to the present invention includes an antenna changeover switch for switching an antenna to a transmission side or a reception side, a transmission power amplifier (HPA) and its power supply terminal, a reception low noise amplifier (LNA) and its power supply terminal, and the current of the HPA. A negative voltage generation circuit for applying a negative voltage necessary for control, a power supply terminal thereof, and a switch control circuit for detecting the power supply of the HPA and switching the antenna changeover switch are provided.
[ 0008 ]
Furthermore, an antenna changeover switch for switching the antenna to the transmission side or the reception side, a transmission power amplifier (HPA) and its power supply terminal, a reception low noise amplifier (LNA) and its power supply terminal, and a negative voltage required for current control of the HPA A negative voltage generating circuit to be applied, a power supply terminal thereof, a switch control circuit for detecting the power supply of HPA and LNA and switching the antenna changeover switch are provided .
[ 0009 ]
DETAILED DESCRIPTION OF THE INVENTION
Reference Example 1
FIG. 1 is a circuit diagram showing a GaAs integrated circuit of a PHS transmission / reception unit, which is Reference Example 1 of the present invention. All the circuits shown in FIG. 1 are high frequency integrated ICs composed of integrated circuits on a GaAs substrate. In the figure, 1 is a transmission power amplifier (HPA), 2 is a negative voltage generation circuit, 4 is a reception low noise amplifier (LNA), and 9 is a power switch for the negative voltage generation circuit. In order for the integrated circuit shown in FIG. 1 to perform the same function as the conventional circuit shown in FIG. 9, the antenna changeover switch (SW) 3, the HPA power switch 5, and the LNA power switch 6 are further provided. The control LSI 7 and the antenna 8 are necessary.
[ 0010 ]
In the PHS including the GaAs integrated circuit configured as described above, the HPA power switch (not shown) is turned on and the power switch 9 for the negative voltage generating circuit is turned on at the time of signal transmission. The signal to be transmitted is amplified by the HPA 1 and transmitted from the antenna 8 (not shown). When receiving a signal, a received signal from the antenna 8 (not shown) is amplified by the LNA 4 and received as a received signal. This signal is demodulated and then converted into an audio signal that can be heard through a speaker. Further, the negative voltage generating circuit 2 is turned off when receiving a signal. Thus, in this reference example , by providing the power supply terminal of the negative voltage generation circuit 2 and the power switch circuit independently, it becomes possible to control the negative voltage generation circuit 2 to operate only during the operation of the HPA 1. It was.
[ 0011 ]
According to the first embodiment, the number of components can be reduced by integrating the HPA 1 and the negative voltage generation circuit 2 on one substrate, and the negative voltage generation circuit 2 is configured on the GaAs substrate. Therefore, it becomes possible to operate at high speed. Further, the current consumption of the negative voltage generation circuit 2 itself can be reduced by turning on only the operation time of the HPA 1. Furthermore, the noise generated by the negative voltage generation circuit 2 can be prevented by turning off the negative voltage generation circuit 2 which is a digital circuit when receiving a signal.
[ 0012 ]
Reference Example 2
FIG. 2 is a circuit diagram showing a GaAs integrated circuit of a PHS transmission / reception unit according to a second reference example of the present invention. In the figure, reference numeral 10 denotes a control circuit for generating a signal for controlling the power supply switch 9 for the negative voltage generating circuit from a signal for switching the antenna changeover switch (SW) 3. In addition, the same code | symbol is attached | subjected to the same and an equivalent part in a figure, and description is abbreviate | omitted.
[ 0013 ]
In the PHS equipped with the GaAs integrated circuit configured as described above, when transmitting a signal, the power supply of the HPA is turned on and the switch SW3 is switched to the transmission side, and this switching signal is used for the power supply for the negative voltage generating circuit. The switch 9 is controlled. That is, when switching SW3 to the transmission side, the negative voltage generation circuit 2 is turned on. The signal to be transmitted is amplified by HPA 1 and transmitted from the antenna through SW 3. When receiving a signal, the switch SW3 is switched to the receiving side, and the power supply switch 9 for the negative voltage generating circuit is controlled using this switching signal. That is, when switching SW3 to the receiving side, the negative voltage generating circuit 2 is turned off. A reception signal from the antenna flows to the reception circuit side by SW3, is amplified by LNA4, and is received as a reception signal. This signal is demodulated and then converted into an audio signal that can be heard through a speaker.
[ 0014 ]
According to the present reference example 2 , the same effect as the reference example 1 can be obtained, and further, the power source of the negative voltage generation circuit 2 is controlled using the switching signal of the SW3. A dedicated signal for controlling the switch 9 can be eliminated. As a result, the number of pins of the IC can be reduced, and wiring on the telephone board when using the IC can be reduced.
[ 0015 ]
Reference Example 3
FIG. 3 is a circuit diagram showing a GaAs integrated circuit of a PHS transmission unit which is Reference Example 3 of the present invention. In the figure, 11 is an HPA power switch integrated on a GaAs substrate, and 12 is a voltage detection control circuit for detecting a HPA gate voltage and generating a signal for controlling the HPA power switch 11. In this reference example , the power supply control signal of the HPA is used to control the power supply of the negative voltage generation circuit 2, and when the output of the negative voltage generation circuit 2 reaches a predetermined value, the power supply switch circuit 11 of the HPA is operated. Is. In addition, the same code | symbol is attached | subjected to FIG.1, 2,9 in FIG.
[ 0016 ]
FIG. 4 shows a configuration example of the voltage detection control circuit 12 of FIG. In the figure, 13 is a voltage detection inverter circuit, and 14 is an AND circuit. N1 to N4 indicate nodes of the respective terminals. When the power control signal N1 of HPA1 is L, N4 is L regardless of N2, the HPA power switch 11 in FIG. 3 is turned off, and no drain voltage is applied to HPA1. When N1 is H, when the output N2 of the negative voltage generation circuit 2 becomes lower than a predetermined voltage and becomes L, N3 becomes H, the power switch 11 is turned on, and the drain voltage is given to the HPA1. Therefore, when the power supply control signal of HPA1 becomes H (ON) at the time of signal transmission, first, the negative voltage generation circuit 2 operates to generate a negative voltage applied to the gate voltage of HPA1, and that this has dropped to a predetermined voltage. After detection, the HPA power switch 11 is turned on to apply power to the HPA 1.
[ 0017 ]
FIG. 5 shows a configuration example of the voltage detection inverter circuit 13 of FIG. 4, and 15 and 16 are depletion type FETs. Wg1 and Wg2 represent the gate widths of the depletion type FETs 15 and 16, respectively. Wg1 and Wg2 are determined by the voltage detected by the voltage detecting inverter circuit 13. When the voltage is 0V, Wg1 = Wg2,
In case of 0V or more, Wg1 <Wg2
In the case of 0V or less, Wg1> Wg2.
According to this reference example 3 , the signal for controlling the power supply of the negative voltage generation circuit 2 and the HPA 1 can be shared, and the system can be easily configured.
[ 0018 ]
Reference Example 4
In Reference Example 1 of the present invention, the threshold voltage (Vth) of the FET constituting the LNA 4 is set to −0.5 V or more, and the HPA1 has a threshold voltage of the FET constituting the HPA1 in order to improve the output power density. The voltage (Vth) is set to −1 V or less.
As a result, the current of the LNA 4 does not require the gate voltage to be 0 V or less, and the negative voltage generation circuit 2 can be operated regardless of the LNA 4.
[ 0019 ]
Embodiment 1 FIG.
FIG. 6 is a circuit diagram showing a GaAs integrated circuit of the PHS transceiver unit according to the first embodiment of the present invention. In the figure, 1 is a transmission power amplifier (HPA), 2 is a negative voltage generation circuit, 4 is a reception low noise amplifier (LNA) , and 17 is a circuit for controlling an antenna switch (SW) 3. This circuit is configured to detect the power source of the HPA 1 and switch the SW. In addition, the same code | symbol is attached | subjected to the same and an equivalent part in a figure, and description is abbreviate | omitted.
In the PHS provided with the GaAs integrated circuit configured as described above, when the power supply of the HPA 1 is off, all the SW3 are switched to the receiving side, and can be received anytime. Only when the power supply of HPA1 is on, SW3 can be switched to the HPA side and transmitted.
According to the present embodiment, a dedicated signal for switching SW3 is not necessary, and it is possible to reduce the number of terminals of the IC and the wiring of the system board. Furthermore, there is an effect of reducing circuit current and power consumption.
[ 0020 ]
Embodiment 2 FIG.
FIG. 7 is a circuit diagram showing a GaAs integrated circuit of the PHS transceiver unit according to the second embodiment of the present invention. In the present embodiment, the antenna switch (SW) control circuit 17 is configured to detect the power source of the HPA 1 and the power source of the LNA 4 and switch the SW.
In the PHS including the GaAs integrated circuit configured as described above, when both the HPA1 and the LNA4 are turned off, the SW3 is not connected to either the transmitting side or the receiving side, and the HPA1 is turned on. In this case, SW3 is switched to the HPA side to enable transmission. When the power supply of the LNA 4 is on, the SW 3 is switched to the LNA 4 side and reception is possible. When both HPA1 and LNA4 are on, there is no occurrence in the system, but both sides are on in the circuit configuration.
According to the present embodiment, a dedicated signal for switching SW3 is not necessary, and it is possible to reduce the number of terminals of the IC and the wiring of the system board. Furthermore, there is an effect of reducing circuit current and power consumption.
[ 0021 ]
Reference Example 5
FIG. 8 is a circuit diagram showing a GaAs integrated circuit of a PHS transmission / reception unit according to Reference Example 5 of the present invention. This reference example shows an example of a package configuration of a plurality of chips. In the figure, 20 is a multi-chip IC of this reference example , 21 is a circuit composed of a GaAs substrate, and 22 is a circuit composed of a Si substrate. Reference numerals 31 to 33 are wires connecting the circuit 21 and the circuit 22.
In the configuration of this reference example , the negative voltage generating circuit 2, the HPA power switch 11 and the antenna switch (SW) control circuit 17 are arranged on the Si substrate 22, and the HPA1, SW3 and LNA4 are arranged on the GaAs substrate 21. ing.
[ 0022 ]
As described above, by making the negative voltage generating circuit 2 a separate chip from the LNA 4 and the HPA 1, it is possible to prevent noise generated by the negative voltage generating circuit 2 from being transmitted through the substrate. Further, since the HPA power supply switch 11 can be composed of an Si element, loss of voltage drop at the switch can be suppressed. Furthermore, since it is sealed in one package, the number of parts can be minimized.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a GaAs integrated circuit constituting a transmission / reception unit of a PHS which is a reference example 1 of the present invention.
FIG. 2 is a circuit diagram showing a GaAs integrated circuit constituting a transmission / reception unit of a PHS which is a reference example 2 of the present invention.
FIG. 3 is a circuit diagram showing a GaAs integrated circuit constituting a PHS transmission unit according to a third embodiment of the present invention.
FIG. 4 is a circuit diagram showing a voltage detection control circuit constituting a GaAs integrated circuit which is Reference Example 3 of the present invention.
FIG. 5 is a circuit diagram showing an example of a voltage detection inverter constituting the voltage detection control circuit.
FIG. 6 is a circuit diagram showing a GaAs integrated circuit that constitutes a PHS transmission / reception unit according to the first embodiment of the present invention;
FIG. 7 is a circuit diagram showing a GaAs integrated circuit constituting a transmission / reception unit of a PHS according to a second embodiment of the present invention;
FIG. 8 is a circuit diagram showing a multi-chip IC constituting a PHS transmitting / receiving unit according to a fifth embodiment of the present invention.
FIG. 9 is a circuit diagram in which a PHS transmission / reception unit is configured using a conventional GaAs integrated circuit.
[Explanation of symbols]
1 Power amplifier for transmission (HPA) composed of GaAs IC,
2 Negative voltage generation circuit, 3 Antenna selector switch (SW),
4 Low noise amplifier (LNA) for reception, 5 HPA power switch,
6 LNA power switch, 7 control LSI composed of SiIC,
8 Antenna, 9 Power switch for negative voltage generator,
10. Control circuit for power switch of negative voltage generation circuit,
11 HPA power switch,
12 HPA power switch control circuit (voltage detection control circuit),
13 Inverter for voltage detection, 14 AND circuit,
15, 16 Depletion type GaAs field effect transistor (FET),
17 switch (SW) control circuit, 20 multi-chip IC,
21. a circuit constructed on a GaAs substrate,
22 Circuit, 31, 32, 33 wire constructed on Si substrate.

Claims (2)

An antenna selector switch for switching the antenna to the transmitting side or the receiving side,
Power amplifier for transmission and its power supply terminal,
Low noise amplifier for reception and its power supply terminal,
A negative voltage generating circuit for supplying a negative voltage necessary for current control of the transmission power amplifier and its power supply terminal;
A GaAs integrated circuit comprising a switch control circuit for detecting a power source of the transmission power amplifier and switching the antenna changeover switch. An antenna selector switch for switching the antenna to the transmitting side or the receiving side,
Power amplifier for transmission and its power supply terminal,
Low noise amplifier for reception and its power supply terminal,
A negative voltage generating circuit for supplying a negative voltage necessary for current control of the transmission power amplifier and its power supply terminal;
A GaAs integrated circuit comprising a switch control circuit for detecting power sources of the transmitting power amplifier and the receiving low noise amplifier and switching the antenna selector switch.

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