JPH10284947A - Amplifier for transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission amplifier in which power consumption is reduced when an output voltage is decreased. SOLUTION: Amplifiers 11, 12 of a same structure are arranged in a form of balancing, and in the case of decreasing an output power, the current/voltage of the amplifier of one side is interrupted at a high speed by using a power switch 21 or 22, low power consumption is realized without deteriorating the high frequency characteristic of the amplifier section. A variable attenuator 15 at the pre-stage of the balanced type amplifier section is provided to vary the gain the combination with a high speed circuit changeover device 31. Through a composite operation of two operations by way of a control circuit 41, high speed output power control is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission amplifier for microwave and millimeter wave bands, and more particularly to a technique for reducing power consumption of a transmission amplifier and a control circuit.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. Hei 7-115331 discloses an amplifying device that operates with high power efficiency and operates with low power consumption even when there is a large change in input power level. A configuration of an amplification device has been proposed.

Referring to FIG. 3, this conventional amplifying device
In an amplifying apparatus provided with a multi-stage amplifier in which unit amplifiers 5 each including a transistor, an input matching circuit, and an output matching circuit are cascaded, a medium-output amplifier including a first-stage amplifier, a high-output amplifier including a final-stage amplifier, According to the input power level of the amplifying device, one of the bypass circuit 16 of the high-power amplifying unit and the high-power amplifying unit cascaded to the medium-power amplifying unit or the circuit bypassing the high-power amplifying unit is selected. Switches 13 and 14 and a variable voltage power supply 17 for changing the power supply voltage of the high-power amplifier in accordance with the input power level of the amplifier when the high-power amplifier is connected are provided. In FIG. 3, reference numeral 6 denotes a signal input terminal of a microwave or millimeter wave signal (hereinafter, referred to as “RF signal”), and reference numeral 7 denotes an RF signal output terminal.

In this conventional amplifying apparatus, when the input power level changes, a high-output amplifying unit including a final-stage amplifier whose efficiency is set high for a predetermined output power is selected according to the input power level. By doing so, it is possible to operate the amplifier with high efficiency, and by cutting off the power supply of unused high-output amplifiers other than those selected, unnecessary power consumption can be omitted to reduce power consumption. It is made to work.

As an example, consider the case where the conventional amplifying device shown in FIG. 3 is applied to a transmitting amplifier of a microwave and millimeter wave portable terminal.

In a portable terminal, when the base station is located at a short distance, the transmission output power can be reduced. Therefore, it is desirable to reduce the power consumption. When the transmitter lowers its transmit output power from full gain, RF
Assuming a constant input power, the gain may be reduced in the amplifier. At this time, to maintain the transmission quality, the transmission output distortion may be maintained at the same amount as that at the time of the full gain, so that the saturation output of the amplifier can be reduced by the reduction of the transmission power output. That is, it is permissible to reduce the transmission saturation output by the transmission gain reduction.

[0007] A very common method of variable gain is to use a variable attenuator such as a PIN diode.
In this case, a decrease in the transmission output power does not lead to a reduction in the power consumption of the transmitter.

Therefore, in the conventional amplifying apparatus shown in FIG. 3, the path of the RF signal is switched to lower the transmission gain, and the power supply of the unit amplifier that does not pass the RF signal is turned off, thereby achieving low power consumption operation. Is being planned.

[0009]

However, the conventional amplifier shown in FIG. 3 has the following problems.

(1) The first problem is that the conventional amplifying device requires a circuit switch having excellent high-frequency characteristics before and after the high-power amplifier.

The first reason is that it is difficult to configure a circuit changeover switch having a small passage loss in the microwave band and the millimeter wave band.

The second reason is that in order to realize a circuit changeover switch without deteriorating high-frequency characteristics, high isolation is required for the switch, and the circuit configuration of the high isolation switch becomes complicated. is there.

(2) The second problem is that in the above-mentioned conventional amplifying device, it is difficult to obtain good high-frequency characteristics if the power supply voltage supplied to the unit amplifier is reduced for low power consumption operation. ,That's what it means.

The reason is that the gain and the input / output reflection coefficient of the unit amplifier change depending on the power supply voltage.

It is possible to solve the above problem by connecting an isolator to the RF input / output terminal of the high-output amplifier and correcting the gain in view of the effect of the gain reduction due to the voltage reduction, but the circuit scale is large. It is not practical because it becomes expensive.

In the millimeter wave band, since the high frequency characteristics of the unit amplifier have a very large voltage dependency, if the voltage is changed, good high frequency characteristics cannot be obtained.

Accordingly, the present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a transmission amplifying apparatus having a high-speed output power variable function and realizing low power consumption. To provide.

[0018]

In order to achieve the above object, a transmission amplifying apparatus according to the present invention controls switching of a power supply of a balanced amplifying section at a high speed when a transmission output power is variable, and attenuates a variable attenuator. The quantity is controlled at high speed.

According to the present invention, there is provided a balanced amplifying section having first and second amplifiers in a balanced configuration, a power switch for switching and controlling a bias voltage of each of the first and second amplifiers, and A variable attenuator provided in a stage preceding the unit, a switch for variably controlling the amount of attenuation of the variable attenuator, and a control circuit for outputting a switching instruction of each switch according to output power. It is characterized by the following.

[Outline of the Invention] The outline of the present invention will be described below. In the present invention, the amplifiers having the same structure (11 and 12 in FIG. 1) are configured as a balanced type, and when the output power is reduced, the power supply voltage of one of the amplifiers is used using a power switch (21 or 22 in FIG. 1). It is characterized by realizing low power consumption without deteriorating the high frequency characteristics of the amplifier.

A variable attenuator (15 in FIG. 1) is provided at a stage preceding the balanced type amplifying section, and a high-speed circuit switcher (3 in FIG. 1) is provided.
Variable gain is performed in combination with 1).

In the present invention, high-speed output power control is realized by performing the above two operations as a combined operation via a control circuit (41 in FIG. 1). Other features.

As described above, in the present invention, since the transmission amplifier is configured as a balanced type, even if one of the amplifiers is turned on or off and the input / output reflection coefficient fluctuates,
Since the reflection coefficient viewed from the amplifier on the opposite side does not deteriorate, the high-frequency characteristics of the balanced amplifier are good.

Further, in the present invention, when it is desired to reduce the output power of the transmitting amplifier, the power of the amplifier can be turned off, so that the power consumption is reduced.

Further, in the present invention, a high-speed power switch is used for turning on and off the power of the amplifier, so that a high-speed change of output power can be realized.

The attenuation control of the variable attenuator can be performed at a high speed because a high-speed circuit switcher can be used. The combined operation of both enables high-speed setting of output power.

[0027]

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

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. Referring to FIG. 1, an embodiment of the present invention comprises:
A high-frequency signal input terminal of the amplifiers 11 and 12 having the same structure is connected to the power divider 13, and a high-frequency signal output terminal of the amplifiers 11 and 12 is connected to the power combiner 14; Side, that is, the power distributor 13
The variable attenuator 15 is provided at the preceding stage, and the bias lines of the amplifiers 11 and 12 are connected to an amplifier bias circuit 23 through power switches 21 and 22, respectively.

The bias line of the variable attenuator 15 is connected to a variable attenuator bias circuit 32 through a circuit switch 31.

Power switches 21 and 22 and circuit switch 3
In FIG. 1, control terminals for inputting signals for controlling the switching are connected to the control circuit 41, respectively. In FIG. 1, 1 is an input terminal, and 2 is an output terminal.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

When the control circuit 41 outputs a command (control signal) for lowering the output power, the power switch 21 for inputting the control signal to the control terminal is turned off (switching to the side b in the figure), and the amplifier 11 is turned off. Becomes At this time, since the bias voltage of the amplifier 11 is forced to the ground potential, a high-speed output reduction is realized. At the same time, the circuit switch 31
By selecting another path of the variable attenuator bias circuit 32, the output power (attenuation) of the variable attenuator 15 is controlled at high speed. Since the amplifier 11 is turned off in the output power reduction state, the power consumption of the amplifier 11 becomes zero.

Conversely, when increasing the output power from the output power reduction state, the control circuit 41 outputs a command (control signal) to increase the output power, and the power switch 2
1 is turned on (switched to the side a in the figure), and the amplifier 11 enters the operating state at high speed. At the same time, the circuit switch 31 selects another path of the variable attenuator bias circuit 32,
The output power of the variable attenuator 15 is controlled at high speed.

Further, when the transmitter output power is to be turned off, the power switch 2 is controlled by a control signal from the control circuit 41.
By cutting off both 1 and 22, the output power of the amplifiers 11 and 12 can be cut off, and the output power from the power combiner 14 is cut off.

[0035]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

Referring to FIG. 1, an embodiment of the present invention is a heterojunction field effect transistor (Hetero Junction).
FET, HJ-FET)
And a high-frequency signal input terminal connected to the power divider 13.
A high frequency signal output terminal of 1 and 12 is connected to a power combiner 14 to provide a balanced high frequency amplifier, and a variable attenuator 15 composed of a PIN diode is provided on the high frequency signal input side of the high frequency amplifier. The drain bias lines of the amplifiers 11 and 12 are connected to an amplifier bias circuit 23 through amplifier power supply ON / OFF switches 21 and 22 each composed of a complementary (complementary) MOSFET. Variable attenuator bias circuit 3 through multiplexer 31
2 and power ON / OFF switches 21 and 22,
The control terminal of the multiplexer 31 is connected to the control circuit 41.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

In the transmission amplifier shown in FIG. 1, for simplicity, it is assumed that the transmitter gain is set to 8 dB and nine steps of output power control are performed in 1 dB steps from a full gain to an output power reduction of 8 dB.

When the control circuit 41 outputs a command to lower the output power, the amplifier power ON / OFF switch 21 is turned off, and the output terminal potential of the switch 21 is forced to the ground potential.

The RF frequency is 30 GHz, the transmitter saturation output power at full gain is 300 mW, and the operating voltage of the amplifier is 5
Assuming that V, the bias set current value of the amplifier currently in practical use is about 100 to 200 mA. In this case, the fall time of about 100 nSec (nanosecond) is realized by the ON → OFF operation of the high-speed MOSFET switch. It is possible.

When the power divider 13 is realized by a Wilkinson divider, an output power drop of 3 dB ideally occurs between the high frequency signal input / output terminals of the power divider 13.
Similarly, when the power combiner 14 is realized by a Wilkinson divider, if the input power to the two input terminals of the power combiner is equal, ideally, the 3 dB output power between the high frequency signal input / output terminals of the power divider 13 is To increase. Further, the Wilkinson divider provides isolation between terminals.

In this ideal balanced amplifier, the drain bias voltage of the amplifier 11 (HJ-FET) is 0
V, the gain is 3 dB due to the loss of the power divider 13.
descend. Therefore, the output power of the transmission amplifier is reduced by 3 dB. At the same time, since the amplifier 11 is turned off, the transmitter saturation output power is also reduced by 3 dB. Due to the isolation between the terminals of the Wilkinson divider, the single characteristic of the amplifier 12 ideally coincides with the case where only the amplifier 11 is turned off in the balanced amplifier.

Simultaneously with the above operation, the multiplexer 31
However, by selecting another path of the variable attenuator bias circuit 32, the set current value of the PIN diode is increased by several tens nSe.
Change with c.

For example, if the output power of the transmission amplifier is 5 dB
To lower the gain, the amplifier 11 is turned off so that the gain 3
By combining the reduction of dB and the reduction of gain of 2 dB by the set current control of the PIN diode, a total reduction of output power of 5 dB is realized. The output power fall time required for these two operations is about 100 nSec.

When the output power is lower than 3 dB, the amplifier 11 is turned off, so that the power consumption of the amplifier 11 becomes zero. Under this assumption, the power consumption is reduced by 0.5 to 1 W.

Although the power consumption of the PIN diode, which is a variable attenuator, increases, it is about 0.05 W and can be ignored.

Conversely, when increasing the output power to the full gain from the state in which the output power is reduced by 5 dB, the control circuit 41 outputs a command to increase the output power to the full gain, so that the power ON / OFF switch 21 is turned from OFF to ON. , And the amplifier 11 is quickly operated. At the same time, the multiplexer 31 selects another path of the variable attenuator bias circuit 32, and thereby the PI
The set current value of the N diode is controlled at high speed. Under this assumption, the output power rise time of the amplifier 11 is several tens.
１００100 nSec.

The reduction of the output power by 3 dB is realized by the amplifier 11.
0 to 8 because it is possible by turning off the drain voltage of
In order to make the output power variable in dB, an 8-channel multiplexer may be prepared.

When the transmission amplifier of this embodiment is applied to a time division multiplexing type transmitter, it is necessary to turn on / off the output power of the transmitter. In this case, the power ON / OFF switch 2 is controlled by a control signal from the control circuit 41.
By turning ON / OFF both 1 and 22, the amplifier 11
ON / OFF control of the output power of the power combiner 14 and the output power of the power combiner 12 can be realized.
It is turned off.

In the above description, a Wilkinson divider is used for the power divider and the power combiner as an example of realizing the balanced amplifier. However, the phase difference at the time of power combining and distributing does not need to be 0 degrees. As long as the terminal isolation is ensured, a 90 degree hybrid or 180 degree
It is also possible to use a degree balun. If this condition is satisfied, the power distribution / combiner can be realized not only with passive devices but also with active devices.

The balanced amplifier may be realized by a hybrid IC in which a high-frequency amplifier using a discrete device and a power distributor / combiner using an alumina ceramic substrate are combined.
onolithic Microwave IC) or in the form of a multi-chip module.
However, it is necessary that the drain voltages of the amplifiers 11 and 12 can be individually controlled.

The amplifiers 11 and 12 have H as an amplifying element.
The J-FET has been described as an example, but the gallium arsenide FE
T or a hetero bipolar transistor may be used.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing the configuration of the second embodiment of the present invention.

Referring to FIG. 2, the second embodiment of the present invention is configured by connecting a balanced type amplifier to the series in the first embodiment shown in FIG. That is, referring to FIG. 2, in the present embodiment, the power switches 121, 122, and 12 corresponding to the front-stage balance amplifier 150 , the rear-stage balance amplifier 151 , and the amplifiers of the respective stages are connected in cascade.
4 and 125 are provided. The variable attenuator 115, the circuit switch 131, and the variable attenuator bias circuit 132
This is the same as the embodiment. Similar to the first embodiment, the description will be made on the assumption that the power gain of the balanced amplifier is 8 dB per stage and the full gain of the transmission amplifier shown in FIG. 2 is 16 dB.

Now, the transmission output power of the transmission amplifier is set to 8 dB.
You want to lower it. The control circuit 141 sets the output power to 8d
When the command to lower B is output, the amplifier power is turned ON / OF.
The F switches 121 and 124 are turned off, and the output terminal potential is forced to the ground potential.

As in the first embodiment, the RF frequency is set to 3
Transmitter saturation output power 300m at 0GHz, full gain
Is W, the operating voltage of the amplifier assuming 5V, considering the power of the amplifier that are currently in practical use, the bias set current value of the pre-stage balanced amplifier 150 about 25～50MA bias set current of the subsequent balanced amplifier 151 The value is about 100 to 200 mA, and in this case, the high-speed M
100n by ON → OFF operation of OSFET switch
A fall time of about Sec can be realized.

At the same time as the above operation, the multiplexer 131
However, by selecting another path of the variable attenuator bias circuit 132, the set current value of the PIN diode is increased by several tens nS.
It changes with ec. For example, if the output power of the transmitter is 8 dB
In the case of lowering, the amplifiers 111 and 116 are turned off to reduce the gain by 6 dB, and by controlling the set current of the PIN diode, the gain is reduced by 2 dB.
Output power reduction of dB is realized.

The fall time of the output power required for these two operations is about 100 nSec. In the output power reduction state of 6 dB or more, the power consumption of the amplifiers 111 and 116 becomes zero. Under this assumption, the power consumption is reduced by 0.625 to 1.25 W. Although the power consumption of the PIN diode, which is a variable attenuator, increases, it is about 0.05 W and can be ignored.

[0059]

As described above, according to the present invention, the following effects can be obtained.

(1) A first effect of the present invention is that the power consumption can be reduced without deteriorating the high-frequency characteristics of the transmission amplifier when the output power is reduced.

The reason is that, in the present invention, by employing a balanced amplifier, it is possible to reduce the power consumption of that part to zero by cutting off one-side operation.

(2) The second effect of the present invention is that the output power of the transmission amplifier can be finely controlled.

The reason is that, in the present invention, by using both the one-sided operation of the balanced amplifier and the attenuation control by the variable attenuator, the accuracy of the capacity of the variable attenuator control circuit switch can be obtained. Because.

(3) A third effect of the present invention is that the output power of the transmission amplifier can be controlled at high speed.

The reason is that according to the present invention, the operating voltage is forcibly turned ON / OFF by using the power switch for the voltage control of the balanced amplifier.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of another embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a configuration of a conventional amplification device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-frequency signal input terminal 2 high-frequency signal output terminal 11, 12 high-frequency amplifier 13 power distributor 14 power combiner 15 variable attenuator 21, 22 high-frequency amplifier power switch 23 high-frequency amplifier bias circuit 31 variable attenuator circuit switch 32 variable Attenuator bias circuit 41 Control circuit 111, 112, 116, 117 Amplifier 113, 118 Power distributor 114, 119 Power combiner 115 Variable attenuator 121, 122, 124, 125 Power switch 123 Amplifier bias circuit 131 Circuit switcher 132 Bias circuit for variable attenuator 141 Control circuit

Claims (5)

[Claims] 1. A transmission amplifier, wherein when a transmission output power is variable, a power supply of a balanced amplifying unit is rapidly switched and controlled, and an attenuation of a variable attenuator is controlled at a high speed. 2. A balanced amplifying section having first and second amplifiers in a balanced configuration; a power switch for switching and controlling a bias voltage of each of the first and second amplifiers; A variable attenuator provided at a preceding stage, a switch for variably switching control of an attenuation amount of the variable attenuator, and a control circuit for outputting a switching instruction of each switch according to output power. Characteristic transmission amplifier. 3. When decreasing the output power, one of the first and second amplifiers of the balanced amplifying unit is cut off via the power switch, and the attenuation of the variable attenuator is reduced as necessary. 3. The transmission amplifier according to claim 2, wherein the output power is reduced by a desired amount of attenuation in combination with the switching of the amount. 4. The balance type amplifying unit comprises a power divider, the first and second amplifiers having the same structure with an output of the power divider as inputs, and the first and second amplifiers. 3. The transmission amplifier according to claim 2, further comprising a power combiner having an output of the amplifier as an input. 5. The transmission amplifier according to claim 2, wherein a plurality of said balanced amplifiers are connected in cascade, and said power switch is provided corresponding to each of said balanced amplifiers.