JPH08149036A - Portable telephone set - Google Patents

Abstract

PURPOSE: To prevent the output of an oscillating circuit from leaking out from an antenna while the power amplifier part of a portable telephone set stops its operation. CONSTITUTION: A power supply part of a buffer amplifier part 20 is connected to two different DC power voltage V2 and V3 (V2 >V3 >0) via a switch 50. The switch 50 changes over the power voltage applied to the part 20 synchronously with the signal that turns on and off the operation of a power amplifier part 10 (V2 and V3 to be selected when the operation of the part 10 is turned on and off respectively). As a result, the gain of the part 20 is reduced when the operation of the part 10 is turned off and therefore the electric power leaking out from an antenna 1 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone, and more particularly to a means for supplying power to a buffer amplification section provided between an oscillation circuit section and a power amplification section.

[0002]

2. Description of the Related Art A conventional example of this type will be described with reference to the drawings.

FIG. 8 is a block diagram showing a first conventional example.

In FIG. 8, a normal voltage controlled oscillator is used for the oscillator circuit section 30, and its output is about 0 dBm. The input level required for the power amplifier 10 is about +7 dBm. Therefore, the output of the oscillation circuit unit 30 is set to the power amplification unit 1
Buffer amplifier 2 for amplifying the input level required for 0
0 is used. The transmission filters 3 and 4 are used to remove unnecessary waves and the like accompanying the transmission waves, and the reception filter 2 is used to remove unnecessary waves and the like accompanying the reception waves. Power amplifier 1
The power source of 0 is connected to the DC power source voltage V ₁ via the switch 40, and is synchronized with the ON / OFF signal.
The operation of 0 is turned on / off. The power supply of the buffer amplification section 20 is connected to the DC power supply voltage V ₂ and is independent of the ON / OFF signal.

FIG. 9 is a block diagram showing a second conventional example.

In FIG. 9, the second conventional example is the first example.
When compared with the conventional example, the DC power supply voltage to the buffer amplification unit 20 is received via the switch 40, and its operation is synchronized with the ON / OFF signal for opening and closing the switch 40.

[0007]

According to the first conventional example, the conventional portable telephone has a buffer amplifying section 2 as shown in FIG.
0 always operates regardless of the ON / OFF signal, so 10 to 20 m while the DC power supply voltage V ₂ is applied.
The current of about A continues to flow, and the operation of the power amplification unit 10 is OF.
There is a problem that the electric power leaking from the antenna 1 is large even when the frequency is F. In recent years, along with the demand for smaller and lighter mobile phones, there is an increasing demand for smaller batteries (lower capacity). To meet this demand, the current (10 to 20 mA) needs to be reduced as much as possible, but there is a problem that the current cannot be reduced in the circuit configuration of the first embodiment.

Next, in the second conventional example, in order to make up for the drawbacks of the first conventional example, the circuit configuration in which the operation of the buffer amplification section 20 is turned on / off in synchronization with the ON / OFF signal to make the current zero. Therefore, the power leaked from the antenna 1 when the operation of the power amplification unit 10 is off is sufficiently smaller than that in the first embodiment, but the power of the buffer amplification unit 20 is synchronized with the ON / OFF signal. Since the input VSWR (voltage standing wave ratio) changes from about 1 to about 40, the buffer amplification unit 2
There is a problem in that the oscillation frequency of the oscillation circuit unit 30 changes (is fluctuated) due to load fluctuations linked to the 0 operation.

[0009]

The mobile phone of the present invention comprises:
A mobile phone having an oscillating circuit section and a power amplifying section for supplying electric power to an antenna, and having at least one buffer amplifying section between the oscillating circuit section and the power amplifying section. A switching means for switching the power supply voltage to two types of DC power supply voltages having different voltage values in synchronism with the operation of the power amplification section, wherein the switching means turns on / off the operation of the power amplification section; The switching means has an input part and an output part connected to each other by a first resistor, and the switching means has an emitter connected to one type of the DC power supply voltage and a collector connected to the buffer amplification part. A transistor connected to a voltage application terminal, the first resistor connecting the emitter and the collector, one end connected to the base of the transistor, and the other end turned on / off the switch. And a second resistor for receiving signals.

[0010]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention.

In FIG. 1, in the first embodiment, an oscillation circuit section 30 for generating an oscillation signal, a buffer amplification section 20 for amplifying an oscillation signal output from the oscillation circuit section 30, and a buffer amplification section 20.
Amplifier 10 which outputs the output of the power transmission circuit 40 to the antenna 1 after passing through the transmission filter 40 and power amplification, and a switch for opening and closing the supply of the DC power supply voltage V ₁ to the power amplification portion 10. 40 and a switch 50 for opening and closing the supply of the DC power supply voltage V ₂ or V ₃ to the buffer amplification section 20.
And a resistor 51 connected between the input and output of the DC power supply voltage V ₂ of the switch 50, and a switch control unit 60 for sending ON / OFF signals for controlling the opening / closing of the switches 40 and 50.
And is configured.

The DC power supply voltages V ₂ and V ₃ are both 0.
Let V ₂ > V ₃ > 0 instead of V.

Next, the operation of the first embodiment will be described.

The switches 40 and 50 are interlocked with each other by an ON / OFF signal from the switch control unit 60. When the switch signal is an ON signal, the switch 40 is turned on and the power amplification unit 10 is in the operating state, and the switch 50 is the buffer amplification unit 20. The DC power supply voltage V ₂ is supplied to the switch 40, and when the signal is an OFF signal, the switch 40 is turned off, and the switch 50 supplies the DC power supply voltage V ₃ to the buffer amplification unit 20.

As described above, in the first embodiment, the DC power supply of the buffer amplification section 20 is connected to the DC power supply voltages V ₂ and V ₃ via the switch 50, and the switch 50 operates the power amplification section 10. In conjunction with (ON / OFF), the buffer amplification unit 2
Since the power source of 0 can be switched to the voltage V ₂ / V ₃ ,
By setting the voltage of the DC power supply voltage V _{3 to} a value lower than V ₂ , the current of the buffer amplification unit 20 when the operation of the power amplification unit 10 is off can be reduced, and at the same time, the buffer amplification unit 20. Since the gain of is reduced, the power leaked from the antenna 1 can be reduced. The resistor 51 prevents the power supply of the buffer amplification unit 20 from being cut off at the moment when the switch 50 switches from the voltage V ₂ to V ₃ (or V ₃ to V ₂ ).

FIG. 4 is a Smith chart in which the parameter S ₁₁ of the transistor when the transistor 2SC4095 is used in the buffer amplification section in the first embodiment is plotted against the change of the DC power supply voltage, and FIG. 5 is the first chart. The figure which shows the gain and consumption current with respect to the fluctuation | variation of the DC power supply voltage of the buffer amplification part in an Example, FIG. 6 is the DC power supply voltage applied when the transistor 2SC4095 is used for the buffer amplification part in this 1st Example, and an input. Voltage standing wave ratio (VSW
R), and FIG. 7 is a diagram showing an example of the relationship between the input VSWR of the buffer amplification section and the fluctuation of the oscillation frequency of the oscillation circuit section in the first embodiment.

In the first embodiment, by setting the DC power supply voltage V ₃ applied to the buffer amplification section 20 to about 1 (V), the voltage standing wave ratio ( VSWR) can be suppressed to about 5.2.

Further, from FIG. 7, by suppressing the VSWR of the input of the buffer amplification section 20 to about 5, the oscillation circuit section 3
The fluctuation of the oscillation frequency of 0 (900 MHz in the first embodiment) can be suppressed to about +50 KHz.

Further, from FIG. 5, if the DC power supply voltages V ₂ = 3 (V) and V ₃ = 1 (V) of the buffer amplifier 20 are set,
Gain and current consumption are significantly reduced as compared with the case where a DC power supply voltage V ₂ = 3 (V) is constantly applied, and leakage of a signal from the oscillation circuit unit 30 to the power amplification unit 10 is reduced. It is possible to reduce the battery consumption.

Furthermore, from the Smith chart of FIG. 4, the VSWR when the DC power supply voltages V ₂ = 3 (V) and V ₃ = 1 (V) are found, and V ₃ = 0 (V) is set. It can be seen that the change in VSWR is smaller than that in the case of the above.

As described above, in the first embodiment, the leakage of power from the antenna 1 and the fluctuation of the frequency of the oscillation circuit section 30 when the power amplification section 10 is off can be reduced as compared with the conventional example. it can.

FIG. 2 shows the second embodiment of the present invention and is a diagram showing only the switches on the buffer amplification section side.

In FIG. 2, the second embodiment is similar to the switch 50 in the first embodiment shown in FIG.
In addition, the other components (not shown) are the same as those in the first embodiment except that the resistor 50 is replaced by a and the resistor 50 is replaced by the resistor 52.

In the second embodiment, the switch 50
When a is closed, the DC power supply voltage V is applied to the buffer amplifier 20.
_{When 2} is applied and the switch 50a is opened, a voltage (corresponding to the DC power supply voltage V ₃ ) obtained by dropping the potential of the DC power supply voltage V _{2 by} the resistor 52 is applied. That is, the DC power supply voltage V ₃ is unnecessary in the second embodiment.

FIG. 3 shows the third embodiment of the present invention, and is a diagram showing only the switches on the buffer amplification section side.

In FIG. 3, in the third embodiment, the switch 50a in the second embodiment shown in FIG. 2 is replaced with a transistor 53, and other constituent elements (not shown) are all the first and second embodiments. Same as the embodiment.

In the third embodiment, when a low (L) (V) voltage of the ON / OFF signal is applied to the base of the transistor 53, the transistor 53 is turned on and a DC power source is supplied to the buffer amplification section 20. Voltage V ₂ is applied, and on the contrary, ON /
When the high (H) (V) voltage of the OFF signal is applied, the transistor 52 is turned off, and the voltage (corresponding to V ₃ ) obtained by dropping the DC power supply voltage V ₂ at the resistor 52 is the buffer amplification unit 20.
Is applied to

In the second and third embodiments as well, for the same reason explained in the first embodiment, the power amplifier 1
It is possible to reduce the leakage of power from the antenna 1 and the frequency fluctuation of the oscillation circuit section 30 when the 0 is OFF as compared with the conventional example.

[0030]

As described above, the present invention has an oscillation circuit section and a power amplification section for supplying radio wave power to an antenna, and at least 1 is provided between the oscillation circuit section and the power amplification section.
In a mobile phone having two buffer amplifying sections, the power amplifying section is provided with switching means for switching the power supply voltage of the buffer amplifying section to two types of DC power supply voltage which are different in voltage value in synchronization with the operation of the power amplifying section. Since the gain and the current consumption of the buffer amplifier when turning off are reduced compared to the conventional one, the leakage power from the antenna can be reduced as compared with the conventional one, and by setting the fluctuation of the applied voltage of the buffer amplifier to be small, Since the voltage standing wave ratio can be suppressed to be smaller than the conventional value, there is an effect that the fluctuation (fluctuation) of the oscillation frequency of the oscillation circuit section can be made smaller than the conventional value.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention and showing only switches on the buffer amplification section side.

FIG. 3 is a diagram showing a third embodiment of the present invention and showing only switches on the buffer amplification section side.

FIG. 4 is a Smith chart in which the parameter S ₁₁ of the transistor when the transistor 2SC4095 is used in the buffer amplification unit in the first embodiment is plotted against the change of the DC power supply voltage.

FIG. 5 is a diagram showing a gain and a consumption current with respect to a change in the DC power supply voltage of the buffer amplification unit in the first embodiment.

FIG. 6 is a diagram showing an example of a relationship between an applied DC power supply voltage and a voltage standing wave ratio (VSWR) of an input when a transistor 5SC4095 is used in the buffer amplification unit in the first embodiment.

FIG. 7 is a diagram illustrating a VS of an input of the buffer amplification unit according to the first embodiment.
It is a figure which shows an example of a relationship between WR and the fluctuation of the oscillation frequency of an oscillation circuit part.

FIG. 8 is a block diagram showing a first conventional example.

FIG. 9 is a block diagram showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Reception filter 3,4 Transmission filter 10 Power amplification section 20 Buffer amplification section 30 Oscillation circuit section 40, 50, 50a Switch 51, 52, 54 Resistance 53 Transistor 60 Switch control section

Claims (4)

[Claims] 1. A mobile phone having an oscillation circuit section and a power amplification section for supplying radio power to an antenna, and having at least one buffer amplification section between the oscillation circuit section and the power amplification section. A mobile phone having a switching means for switching the power supply voltage of the buffer amplification unit to two types of DC power supply voltages having different voltage values in synchronization with the operation of the power amplification unit. 2. The mobile phone according to claim 1, wherein the switching means is interlocked with a switch for turning on / off the operation of the power amplification section. 3. An input unit and an output unit of the switching means are first.
The mobile phone according to claim 1 or 2, wherein the mobile phone is connected by the resistor. 4. The switching means includes a transistor whose emitter is connected to one type of the DC power supply voltage and whose collector is connected to a voltage application terminal of the buffer amplification section, and the first transistor which connects between the emitter and the collector. 4. The portable device according to claim 1, further comprising a resistor and a second resistor having one end connected to the base of the transistor and the other end receiving a signal for turning on / off the switch. Telephone.