JPH10209763A - Transistor amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable low-voltage operation and make power consumption low by connecting a 1st power source which performs gain control and a 2nd power source, which has its on/off state of voltage application switched in synchronism with the on/off state of a burst waveform to the base of a transistor(TR), which shapes a constant-amplitude input signal into a burst waveform and outputs it. SOLUTION: To shape the constant-amplitude input signal from an input terminal 12 into a burst waveform, a 1st power source V1 for gain control outputs the lowest voltage in a non-output period and the gain of a 1st bipolar TR 11 is made minimum for suppressing the output power. When the burst waveform is outputted from an output terminal 13, the voltage V1 is gradually raised from the lowest level at rise, the gain is varied until the output reaches a specific power, and a reverse procedure is allowed at a fall. The 2nd power source V2 turns on, only when the burst wave is outputted and turns off together with the TR 11 at non-output time, so that no electric power is consumed. Consequently, the variation quantity of the gain is relaxed, and controllability becomes high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transistor amplifier mainly using a bipolar transistor using a compound semiconductor such as silicon or gallium arsenide as an amplifying element, which is mainly used in a transmitting section of a portable telephone or the like.

[0002]

2. Description of the Related Art GSM (Global System for Mobile) is a European digital cellular system.
le Communications) is currently adopted in nearly 100 countries outside of Europe and is mainstream worldwide. Small portable terminals such as mobile phones,
R & D efforts are being made vigorously to reduce the weight, but if all the active components that make up a mobile terminal operate with a single positive power supply, a negative power supply or negative voltage generation circuit is not required, making the terminal compact and lightweight. Silicon NPN capable of operating with a single positive power supply as a power amplifying device for transmission
Bipolar transistors and gallium arsenide heterojunction bipolar transistors (hereinafter, referred to as GaAs HBTs) can be promising devices in the future.

In particular, GaAs HBTs are superior to silicon bipolar transistors in terms of high-frequency characteristics when operating at a low collector voltage, so that the number of batteries is reduced to reduce the size and weight of portable terminals, and the power supply voltage of terminals is reduced. It is expected to be an important device that shows its true value when lowered. In GSM, TDMA (T
im Division Multiple Acc
ESS) is employed, and transmission is performed with a burst waveform of 12.5% duty. As a modulation method, GMSK (Gaussian Mi), which is a type of constant amplitude modulation, is used.
Since the maximum shift keying is employed, the formation of a burst waveform and the control of transmission power are performed by controlling the gain of a transmission power amplifier for an input signal having a constant amplitude.

As a first conventional circuit for forming a burst waveform as described above, FIG. 7 shows a common-emitter power amplifier using bipolar transistors, and FIG. 9 shows a burst waveform forming method by gain control of the conventional circuit. Show. Reference numeral 71 is the bipolar transistor, V ₁ is a first power source, R ₁₁ for gain control is base bias resistor of the bipolar transistor 71. When biasing the base by resistance division is required resistor Ra, when biasing the base current by the resistance value of the bias resistor R ₁₁ may not resistance Ra. An input signal having a constant amplitude is input from the input terminal 72 to the base of the bipolar transistor 71, passes through the collector, and outputs a burst waveform from the output terminal 73.

In order to form a burst waveform from an input signal having a constant amplitude, as shown in FIG. 9, the output from the _first power supply V1 is kept at the lowest level V1min during a period during which transmission is not performed.
(Generally 0 to 0.5 V) to turn off the bipolar transistor 71.

An input signal having a constant amplitude has a constant power,
FIG. 9 shows a state where an input signal having a constant value of power is being input.

When outputting a burst waveform, the rising of the burst waveform is performed by applying the voltage from the _first power supply V ₁ to V ₁ min.
And gradually increases the gain of the transistor amplifier until the output from the transistor amplifier reaches a predetermined power P ₀ (V = V1a). The output from the _first power supply V1 at this time is variable, and can output up to the maximum voltage V1max. The falling of the burst waveform is formed by performing a procedure reverse to the rising of the burst waveform. The period from the rise from P _OFF to the fall from P ₀ is the burst transmission period, and one frame is the period from the start of the burst waveform rising to the rising of the next burst waveform.

FIG. 8 shows a second conventional circuit of a common-emitter type power amplifier using a bipolar transistor. Reference numeral 81 denotes a first bipolar transistor for amplifying a signal, V ₁ denotes a first power supply for controlling a gain,
cc is the main power source of the terminal, 82 the second bipolar transistor for the base current supply of the first bipolar transistor 81, R ₂₁ is the base bias resistor of the second bipolar transistor 82. The first power supply V ₁ was, usually has a lower voltage than the main power source Vcc terminal. When biasing the base of the second bipolar transistor 82 by the resistance division is required resistor Rb, when biasing the base current by the resistance value of the bias resistor R ₂₁ may not resistance Rb. An input signal from the input terminal 83 is input to the base of the first bipolar transistor 81, and a burst waveform is output from the output terminal 84 through the collector. Although the circuit of the second conventional circuit is more complicated than that of the first conventional circuit, the base current of the first bipolar transistor 81 is supplied from the main power supply Vcc (for example, an output directly connected to a battery) of the terminal. Power supply V ₁
Current to be supplied from the second bipolar transistor 8
Can be reduced by a factor of 2 in the current gain component, it is possible to reduce the first load of the power supply V _1. Further, the base of the first bipolar transistor may have a resistor Rb for dividing the resistance.

[0009]

However, since the on-current of about 0.7 V in the case of silicon and about 1.3 V in the case of GaAs HBT is required between the base and the emitter of the bipolar transistor, the following is required. There were challenges.

First, the problem will be described based on a first conventional circuit. A first output voltage from the power source V ₁ V1 (V1
<V1max: maximum output voltage), and the on-voltage between the base and the emitter of the bipolar transistor is Von. Since the voltage drop due to the base current can be ignored until the bipolar transistor is turned on, if the base potential of the bipolar transistor 71 of the first conventional circuit is Vb1, then Vb1 = V1 (Equation 1).

Further, the first maximum voltage width Vw of the power supply V ₁ for controlling the gain of the transistor amplifier, in the case of the first conventional circuit expressed as Vw = V1max-Von (Equation 2).

In the case of the second conventional circuit, the output voltage from the _first power supply V1 for gain control is set to V1 (V1 <V1max: maximum output voltage) until the bipolar transistor is turned on. Assuming that the base potential Vb2 of the second bipolar transistor 82 of the conventional circuit is Vb2 = V1 (Equation 3).

Further, the first maximum voltage width Vw of the power supply V ₁ for controlling the gain of the transistor amplifier is a bipolar transistor 81 and the base - for emitter junction is tandem junction, the base potential Vb2 of the bipolar transistor The bipolar transistors 81 and 82 do not turn on until Vb2 = 2Von (Equation 4), and Vw = V1max-2Von (Equation 5).

At present, the power supply voltage of a battery of a portable terminal for digital transistor cellular such as GSM is 4.8 V in a 4-cell nickel-metal hydride battery serial connection configuration, but in order to further reduce the size and weight of the portable terminal. There is a strong demand to shift the power supply voltage to 3.6 V of a three-cell nickel-metal hydride battery connection configuration or a one-cell lithium-ion battery configuration.

As the power supply voltage decreases, the first power supply V
_Although the maximum output voltage V1max from ₁ also decreases, the maximum voltage width Vw decreases more than the reduction rate of V1max as V1max decreases because of the presence of the on-voltage Von. The smaller the maximum voltage width Vw is, the smaller the maximum V is from the non-output state to the predetermined output power P ₀ during burst output.
It must be set large rate of change until the voltage V1a from 1min, formation accuracy of the burst waveform unless enhanced first output accuracy of the power supply V ₁ is lowered. In some cases, the risk of causing fatal spurs at levels that deviate from the standard of the system due to waveform distortion at the time of rising or falling of the burst waveform increases. Further, the problem is more serious in the case of the second conventional circuit than in the case of the first conventional circuit, and the problem is more serious in the case of GaAs HBT than in the case of silicon bipolar transistor. More than quasi-microwave used in mobile communications (800
In the frequency range of more than 1 MHz, the GaAs HBT has a higher power added efficiency at the time of low voltage operation than the silicon bipolar transistor, and greatly contributes to the reduction of the current consumption of the portable terminal and the extension of the talk time. The significance is very large.

Accordingly, it is an object of the present invention to provide a novel transistor amplifier which can operate at a low voltage and consumes low power by solving the above problems.

[0017]

According to a first aspect of the present invention, there is provided a transistor amplifier using a transistor for shaping a constant amplitude input signal into a burst waveform by gain control and outputting the burst waveform. And a second power supply that switches on / off the voltage application in synchronization with the on / off state of the burst waveform. And a power source.

According to a second aspect of the present invention, there is provided a transistor amplifier using a transistor for shaping a constant amplitude input signal into a burst waveform by gain control and outputting the burst waveform, wherein the first transistor, the second transistor, and the second transistor are connected to each other. A voltage supply means connected to a base of the first transistor, a voltage supply means for controlling the gain, a first power supply for performing gain control, A second power supply that switches on and off states of voltage application in synchronization with the on and off states of the waveform.

Further, in a transistor amplifier using a transistor for shaping a constant-amplitude input signal into a burst waveform by gain control and outputting the same, a gain control is applied to a first transistor and a base of the first transistor. A first power supply, a second transistor, and a voltage supply means having an emitter connected to the base of the first transistor, a voltage supply means connected to the base of the second transistor, The voltage supply means includes a second power supply that switches on and off states of voltage application in synchronization with on and off states of the burst waveform.

Further, the first power supply is connected via a first resistor, the second power supply is connected via the second resistor, the first power supply outputs a lowest voltage, Preferably, the first and second resistors are set so that the first and second transistors are of class B or C when the second power supply outputs a voltage.

The present invention is particularly effective when the first and second transistors are gallium arsenide-based compound heterojunction bipolar transistors.

[0022]

FIG. 1 shows a transistor amplifier according to the present invention as an embodiment, and FIG. 6 shows a method of forming a burst waveform.

In FIG. 1, reference numeral 11 denotes a bipolar transistor. (Hereinafter, the bipolar transistor in the embodiment is a silicon bipolar transistor or GaAs.
HBT. ) V ₁ is the second power supply first power to control the gain of the transistor amplifier, V ₂ is the synchronization with the burst signal on-off state is a state switched, via a respective resistor R _11, R ₁₂ Connected to the base of bipolar transistor 11. When the base is biased by resistance division, Ra may not be provided when the base current is biased by the resistance value of the resistor Ra. The signal is input to the base and output from the collector.

Since the input signal having the constant amplitude forms a burst waveform from the input terminal 12, as shown in FIG.
The output from _{1 is set} to the minimum level V1min, and the output power is suppressed by minimizing the gain of the transistor amplifier. When performing a burst waveform output from the output terminal 13, rising of the burst waveform, the first power V ₁ V1
min and gradually increase the output to a predetermined power P
_o Change the gain of the transistor amplifier until it reaches (V1 = V1a). When the burst waveform falls, the burst waveform is formed by performing the reverse procedure of the burst waveform rising.

When outputting a burst waveform, the first bipolar transistor 1 is not turned on.
In _first voltage region, the resistance value of the resistor R ₁₁ and R1, the resistance value of the resistor R ₁₂ and R2, the second voltage value of the power supply V ₂ V
Assuming that 2, the base potential Vb1 of the first bipolar transistor 11 is as follows: Vb1 = V1 + R1 (V2-V1) / (R1 + R2) (Equation 6), which is ΔV = R1 (V2−V1) / (R1 + R2) (Expression 7) is a higher value, and it is possible to turn on the transistor by lowering the output voltage V1 from the _first power supply V1 than in the case of the first conventional circuit. As a result, the maximum voltage width Vw can be increased as compared with the first conventional circuit.

FIG. 10 is a diagram showing the relationship between the control voltage output from the first power supply V ₁ and the output voltage. In the first conventional circuit, the on-voltage is high, so that the curve rises sharply, whereas in the circuit of the present invention, the curve rises gently, and the controllability is high.

Further, the second power supply is turned on only when the burst waveform is output, and the second power supply and the first transistor are turned off during the non-output time, so that no power is wasted at the time of non-output time.

In this embodiment, the first power supply V ₁ and the second power supply V ₁
Since the power supply V ₂ of is in electrically connected state via the first resistor R ₁ and a second resistor R _2, the base bias of the bipolar transistor, a first resistor R ₁₁ and a second resistor R _It depends on the value of ₁₂ and the ratio of each resistance value.

Also, it is turned on in synchronization with the burst waveform output.
Second on-timing source V ₂ to off, faster than the rise of at least the burst waveform, timing of off, but functions effectively optionally slower than the fall of at least a burst waveform, in which case V1
b = a Vlmin, arises period in which the second power supply V ₂ is turned on. During this period, when the second transistor by the power supply V ₂ is turned on, isolation transistor amplifier is not necessarily good, there is a case where the standard or more signals in the system during non-transmission is output from the transistor amplifier.

[0030] In this case, in the V1b = a V1min second power supply V ₂ is turned on, the transistor sets a resistance value of the bias resistor R _11, R ₁₂ to be a class B or class C, By suppressing the gain of the transistor amplifier, the isolation can be improved.

(Embodiment 2) FIG. 2 shows a second embodiment of the present invention. Reference numeral 21 denotes a first signal for amplifying an input signal.
Is a second bipolar transistor for supplying the base voltage of the first bipolar transistor 2, and Vcc is a main power supply of the terminal. V ₁ was first power to perform gain control, V ₂ is the second power source in synchronization with the burst signal on-off state switched state, the first bipolar through respectively resistors R ₂₁ and R ₂₂ Connected to the base of transistor 21. When biasing the base of the second bipolar transistor 22 by the resistance division is required resistor Rb, when biasing the base current by the resistance value of the resistor R _11, R ₁₂ is the resistance R
b need not be present.

An input signal is input from an input terminal 23 to the base of the first bipolar transistor 21 and a burst waveform is output from an output terminal 24 via a collector. The burst waveform forming method is the same as that of the first embodiment. However, as in the first embodiment, the maximum voltage width Vw can be increased as compared with the second conventional circuit. Further, in the present embodiment, since a part of the base current to be supplied to the first bipolar transistor 21 can be supplied from Vcc, the current supplied from the first power supply V ₁ is reduced, and the first power supply V ₁ The load on the device is reduced. First power supply V ₁ and second power supply V
₂ is electrically connected via the first and second resistors R ₂₁ and R ₂₂ , the second bipolar transistor 22
Is determined by the resistance values of the first and second resistors R ₂₁ and R ₂₂ and the ratio of the two resistance values.

When a burst waveform is output from the output terminal 24,
In the area of voltage which the second bipolar transistor 22 is not turned on, and the resistance value of the resistor R ₂₁ and R1, the resistance value of the resistor R ₂₂ and R2, the second voltage value of the power supply V ₂ and V2, the second Base potential V of bipolar transistor 22
b2 becomes Vb2 = V1 + R1 (V2-V1) / (R1 + R2) (Equation 8), and it becomes possible to turn on the transistor at a lower voltage than in the case of the second conventional circuit. Can also increase the maximum voltage width Vw. Further, as in the first embodiment, the second power supply V ₂ is turned on only when the burst waveform is output, and when the burst waveform is not output, the second power supply V ₂ is turned on.
_{Since the second} and first bipolar transistors 21 are turned off, no power is wasted during non-output.

(Embodiment 3) FIG. 3 shows a third embodiment of the present invention. Reference numeral 31 denotes a first bipolar transistor for amplifying a signal, 32 denotes a second bipolar transistor for supplying a base current of the bipolar transistor 31, and Vcc denotes a main power supply of the terminal. V ₁ is a first power supply for controlling the gain of the transistor amplifier, V ₂
Is a second power supply whose on / off state is switched in synchronization with the burst waveform. The first power supply includes the bases of the first and second bipolar transistors 31 and 32 and the resistors R ₁₁ and R ₂₁ , respectively. And the second power supply is connected to the first, second
Are connected to the bases of the bipolar transistors 31 and 32 via resistors R ₁₂ and R ₂₂ , respectively. When biasing the bases of the first and second bipolar transistors 31 and 32 by resistance division, resistors Ra and Rb are necessary,
When the base current is biased by the resistance values of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ , Ra may be omitted. Input terminal 33
, An input signal is input to the base of the first bipolar transistor 31, and a burst waveform is output from the output terminal 34 through the collector. The burst waveform forming method is the same as that of the first embodiment, and the maximum voltage width Vw can be increased as compared with the second conventional circuit as in the first embodiment. In the second embodiment, the first bipolar transistor 31 does not turn on unless at least the second bipolar transistor 32 turns on. However, in the third embodiment, the base of the first bipolar transistor 32 also has the resistor R _11. , because it is biased by the first and second power supply V _1, V ₂ through R _12, can further expand the maximum voltage width Vw than the second embodiment. In this embodiment, since a part of the base current to be supplied to the first bipolar transistor 31 can be supplied from the Vcc, the first current supplied from the power source V ₁ is being reduced, the first load of the power supply V ₁ Is reduced.

(Embodiment 4) FIG. 4 shows a fourth embodiment of the present invention. In FIG. 4, reference numeral 41 denotes a first bipolar transistor for signal amplification, and reference numeral 42 denotes a second bipolar transistor for supplying a base current of the first bipolar transistor 6.
The bipolar transistor Vcc is the main power supply of the terminal. V ₁ was a second power supply first power to control the gain of the transistor amplifier, V ₂ is the synchronization with the burst signal on-off state is a state switched, the first power supply first
And the base of the bipolar transistor 41 of, is connected via a resistor R _11, connected to the second power supply V ₂ via a first, a base of the second bipolar transistors 41 and 42, each resistor R _12, R ₂₂ Is done. When biasing the bases of the first and second bipolar transistors 41 and 42 by resistance division, the resistors Ra and Rb are necessary,
R _11, R _12, when biasing the base current by the resistance value of R ₂₂ is Ra, Rb or if not. Input terminal 43
, An input signal is input to the base of the first bipolar transistor 41, and a burst waveform is output from the output terminal 44 through the collector. The gain control of the transistor amplifier is performed by controlling the base voltage of the first bipolar transistor 41 by the first power supply V ₁ ,
The burst waveform forming method is the same as that of the first embodiment, and the maximum voltage width Vw can be expanded as compared with the first conventional circuit as in the first embodiment. In this embodiment, since a part of the base current to be supplied to the first bipolar transistor 41 can be supplied from the Vcc, the first current supplied from the power source V ₁ is being reduced, the first load of the power supply V ₁ Is reduced.

(Fifth Embodiment) A fifth embodiment of the present invention.
The state is shown in FIG. In FIG. 5, reference numeral 51 denotes a first signal amplifying unit.
The bipolar transistor 52 is a first bipolar transistor.
Second bipolar for supplying base current of transistor 51
The transistor, Vcc, is the main power supply of the terminal. V₁Is
A first power supply for controlling the gain of the transistor amplifier, V_TwoIs
The on / off state is switched in synchronization with the burst waveform output.
It is a second power supply that is replaced. First power supply V ₁Is the first bus
The base of the bipolar transistor 51 and the resistor R₁₁Through
Connected to the second power supply V_TwoIs the second bipolar transformer
The base of the resistor 52 and the resistor R_{twenty two}Connected via
First and second bipolar transistors by resistance division
When biasing the bases of 51 and 52, resistors Ra and R
b is required and R₁₁, R_{twenty two}Base resistance depending on the resistance
When biasing the flow, Ra and Rb need not be provided. Entering
The input signal from the input terminal 53 is the second bipolar transistor
Input to the base of the data 52, and output through the collector
From 54, a burst waveform is output. Transistor amplification
The gain control of the filter is performed by the first power supply V₁By the first bipo
By controlling the base voltage of the
The burst waveform forming method is the first embodiment.
Same as state. In the present embodiment, the second power supply V_TwoEffect
The result is the base-emitter voltage of bipolar transistor 52.
Part 4 is partially offset by the voltage drop of the voltage Von.
Although it is not as effective as the first embodiment, the first embodiment differs from the first embodiment.
Similarly, it is possible to increase Vw compared to the first conventional circuit.
The circuit is simpler than that of the fourth embodiment.
It is. Also in the present embodiment, the first bipolar tiger
A part of the base current to be supplied to the transistor 51 is Vcc
From the first power supply V₁Current supplied from
The first conventional circuit is a gain control power supply compared to the first conventional circuit.
1 power supply V₁The load on the device is reduced.

[0037]

According to the present invention, low voltage operation is possible,
A novel transistor amplifier with low power consumption can be provided. Further, it is possible to provide a power transistor amplifier using a bipolar transistor which has a gradual change in gain with respect to the control voltage and has high controllability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a transistor amplifier of the present invention.

FIG. 2 is a circuit diagram of a transistor amplifier of the present invention.

FIG. 3 is a circuit diagram of a transistor amplifier of the present invention.

FIG. 4 is a circuit diagram of a transistor amplifier of the present invention.

FIG. 5 is a circuit diagram of a transistor amplifier of the present invention.

FIG. 6 is a diagram showing a burst waveform forming method according to the present invention.

FIG. 7 is a circuit diagram of a conventional transistor amplifier.

FIG. 8 is a circuit diagram of a conventional transistor amplifier.

FIG. 9 is a diagram showing a conventional burst waveform forming method.

FIG. 10 is a diagram illustrating a relationship between an output voltage and a control voltage.

[Explanation of symbols]

11, 21, 31, 41, 51 First bipolar transistor 22, 32, 42, 52 Second bipolar transistor 12, 23, 33, 43, 53 Input terminal 13, 24, 34, 44, 54 Output terminal R ₁₁ , R ₁₂ , R ₁₃ , R ₁₄ , Ra, Rb Resistance V ₁ First power supply V ₂ Second power supply Vcc Main power supply

Claims (5)

[Claims] 1. A transistor amplifier using a transistor for shaping a constant-amplitude input signal into a burst waveform by gain control and outputting the burst waveform, comprising: voltage supply means connected to a base of the transistor; A transistor amplifier comprising: a first power supply for performing gain control; and a second power supply that switches on and off states of voltage application in synchronization with on and off states of the burst waveform. 2. A transistor amplifier using a transistor for shaping a constant-amplitude input signal into a burst waveform by gain control and outputting the burst waveform, wherein a first transistor, a second transistor, and an emitter of the second transistor are configured as follows. Voltage supply means connected to the base of the first transistor, connected to the base of the second transistor, the voltage supply means performs a gain control, a first power supply, and an on / off state of the burst waveform A second power supply whose voltage application switches on / off in synchronization with the second power supply. 3. A transistor amplifier using a transistor for shaping a constant amplitude input signal into a burst waveform by gain control and outputting the burst waveform, wherein: a first transistor; and a first transistor for performing gain control on a base of the first transistor.
A power supply, a second transistor, an emitter of the second transistor connected to a base of the first transistor, a voltage supply unit connected to a base of the second transistor, and the voltage supply unit. And a second power supply that switches on and off states of voltage application in synchronization with the on and off states of the burst waveform. 4. The first power source is connected via a first resistor, the second power source is connected via the second resistor, the first power source outputs a lowest voltage, The first and second resistors are set so that when the second power supply outputs a voltage, the first and second transistors are of class B or class C. 4. The transistor amplifier according to any one of 1 to 3. 5. The transistor amplifier according to claim 1, wherein said first and second transistors are gallium arsenide-based compound heterojunction bipolar transistors.