JPH0832367A - Push-pull amplifier - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a push-pull amplifier that does not generate crossover distortion in principle while maintaining the same efficiency as class B. [Structure] Transistors 101 and 102 having the same polarity and having their bases connected to each other, and transistors 103 and 104 having the opposite polarities and having their bases connected to each other, and a connection between the transistor 101 and the emitter of the transistor 103. The input signal is connected to the point, the emitters of the transistors 102 and 104 are connected, the collector and the base of the transistors 101 and 104 are connected, and a current source is connected to the collector of the transistor 104 and the transistor 102 is connected to the collector.
A constant potential is connected to the collector of the transistor 1
The output waveform of the push-pull amplifier does not cause crossover distortion, and the input / output characteristics are non-linear in advance so that the idling current is reduced. It has become.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push-pull amplifier, and more particularly to a push-pull amplifier which eliminates crossover distortion without increasing the idling current of an output stage and is highly efficient.

[0002]

2. Description of the Related Art The following conditions are required to obtain the input / output characteristics of a push-pull amplifier during distortion-free operation. Now, assuming that the input voltage of an active element (ideal active element whose output current is regulated only by the input voltage) responsible for a half cycle of the push-pull amplifier is x and the output current is y, its transfer characteristic is expressed by equation (1). Be done. y = f (x) (1) Further, the transfer characteristic of the active element which takes charge of the remaining half cycle of the push-pull amplifier is graphically f
Expression (2) is obtained by rotating (x) 180 degrees around the origin. y = −f (−x) (2) The combined transfer characteristic y of the push-pull operation is (1), (2)
The characteristic expressed by the equation is superimposed on the vertical axis, and can be expressed by the equation (3). y = f (x) -f (-x) (3) This combined transfer characteristic is linear, that is, the condition for no crossover distortion is that y is a straight line, that is, f (x) -f ( -X) = kx (k is a constant) (4). Here, the crossover distortion is distortion that occurs at the joint of the combined waveforms in the push-pull operation.

Differentiating both sides of equation (4) by x gives (5)
The formula is obtained. f ′ (x) + f ′ (− x) = k (5) Since f ′ (x) is nothing but gm (transconductance), the linear (that is, distortion-free) condition in the push-pull amplifier of equation (4) is , And gm (x) + gm (−x) = k (6).

As described above, in the push-pull amplifier, linear operation is obtained when the transfer characteristic thereof satisfies the expression (4).

FIG. 6 shows a bias circuit of a conventional class A push-pull amplifier having an active element having the above characteristics. A drive stage is configured by the transistors 501 and 502, and the output stage includes power transistors 508, 509,
It consists of a two-stage Darlington emitter follower consisting of 511 and 512. The resistors 513 and 514 are resistors having resistance values RE1 and RE2, respectively, for preventing thermal runaway.

The bias circuit of this push-pull amplifier includes silicon diodes 503 to 506 and a variable resistor 5.
It is composed of a series circuit with the power supply circuit 07, and supplies the idling current Iid required by the equation (7) to the power transistors 508, 509, 511 and 512. Iid = (Vbias−ΣVbe) / (2Re) (7) where ΣVbe is the power transistors 508, 509,
511, 512 sum of each base-emitter voltage, V
bias is the terminal voltage of the bias circuit, Re is the emitter resistance of each transistor, and 2Re = RE1 + RE2.
The silicon diodes 503 to 506 have a forward voltage of about 0.6 V and about -2.3 mV, like the power transistors.
Since it has a temperature coefficient of / ° C, a required bias voltage can be obtained by connecting four diodes in series, and temperature compensation can be performed. Power transistor 5
The operating points (idling currents) of 08, 509, 511 and 512 are set to ½ of the maximum output in the case of class A. The variable resistor 507 adjusts the idling current.

[0007]

The conventional push-pull amplifier configured as described above does not cause crossover distortion in class A operation, but has a problem of poor efficiency because of large idling current. To improve efficiency,
Class B operation is desirable, but class B operation has a problem that crossover distortion is large.

Therefore, an object of the present invention is to provide a high-efficiency push-pull amplifier which, in principle, maintains efficiency equivalent to that of class B and does not generate crossover distortion in principle.

[0009]

In order to solve the above-mentioned problems, a push-pull amplifier according to one aspect of the present invention includes a signal generating means for outputting a pair of signals having phases different from each other by 180 degrees in response to an input signal. , A first amplification means and a second amplification means for amplifying respective output signals of the signal generation means, and a common load by combining respective output signals of the first amplification means and the second amplification means. In a push-pull amplifier having a signal synthesizing unit for extracting a signal, the signal generating unit has a first base whose polarity is connected to each other.
And a second transistor, and third and fourth transistors having opposite polarities to the first and second transistors and having their bases connected to each other.
The first transistor and the third transistor.
The emitters of the transistors are connected to each other, the input signal is connected to this connection point, the emitters of the second and fourth transistors are connected, and the first transistor and the fourth transistor are respectively a collector and a base. Are connected to each other, a current source is connected to the collector of the fourth transistor, a collector of the second transistor is connected to a constant potential, and collectors of the first transistor and the third transistor are connected to each other. It is configured to output the pair of signals.

A push-pull amplifier according to another aspect of the present invention is a signal generating means for outputting a pair of signals having phases different from each other by 180 degrees in response to an input signal, and amplifying respective output signals of the signal generating means. A push-pull amplifier having a first amplifying means, a second amplifying means, and a signal synthesizing means for synthesizing respective output signals of the first amplifying means and the second amplifying means to extract a signal to a common load. In the above, the signal generating means includes first and second transistors having the same polarity and mutually connected bases, and the first and second transistors.
And a third transistor having opposite polarities to each other and having bases connected to each other, and the emitters of the first transistor and the third transistor are connected to each other,
The input signal is connected to this connection point, and the second and fourth signals are connected.
The emitter of the second transistor is connected, the collector and the base of the second transistor and the fourth transistor are connected to each other, and the current source is connected to the collector of the fourth transistor. The collector of the transistor is connected to a constant potential, and the collectors of the first transistor and the third transistor are configured to output the pair of signals.

In a push-pull amplifier according to still another aspect of the present invention, in response to an input signal, a signal generating means for outputting a pair of signals having phases different from each other by 180 degrees and an output signal of each of the signal generating means. Push-pull having a first amplifying means and a second amplifying means for amplifying, and a signal synthesizing means for synthesizing respective output signals of the first amplifying means and the second amplifying means to extract a signal to a common load. In the amplifier, the signal generating means includes first and second transistors having the same polarity and having their bases connected to each other, and first and second transistors having the opposite polarity to the first and second transistors and having their bases connected to each other. 3 and a fourth transistor, the emitters of the first transistor and the third transistor are connected, the input signal is connected to this connection point, and the second and fourth transistors are connected. Of the second transistor and the fourth transistor are connected between the collector and the base of the second transistor, respectively, and the collector of the fourth transistor is connected to a constant potential. A current source is connected to the collector, and the pair of signals is output from the collectors of the first transistor and the third transistor.

In the push-pull amplifier, all or some of the transistors connected between the collector and the base may be replaced with diodes.

A push-pull amplifier according to yet another aspect of the present invention is responsive to an input signal I and is in phase with one another.
Signal generating means for outputting a pair of signals different by 80 degrees, first amplifying means and second amplifying means for amplifying respective output signals of the signal generating means, the first amplifying means and the second amplifying means. In a push-pull amplifier having a signal combining means for combining respective output signals of the means to extract a signal to a common load, the input signal I and a first signal I1 forming a pair of signals from the signal generating means. And the second signal I2, the first signal I1 is I1 = I as the input signal I increases with respect to a positive value of the input signal I.
While the input signal I is represented by a first function that asymptotically approaches a predetermined constant value for near zero and negative values, the second signal I2 being It is constructed so as to be represented by a second function in which the combined output with the signal I1 has a linear relationship.

In a push-pull amplifier according to another aspect of the present invention, in response to an input signal I, a signal generating means for outputting a pair of signals having phases different from each other by 180 degrees and an output signal of each of the signal generating means are provided. Push-pull having a first amplifying means and a second amplifying means for amplifying, and a signal synthesizing means for synthesizing respective output signals of the first amplifying means and the second amplifying means to extract a signal to a common load. In the amplifier, the first signal I1 of the input signal I and the first signal I1 and the second signal I2 forming a pair of signals from the signal generating means is the input signal I and the input signal I2. With constant values K1 and K2 irrelevant to the signal I, K1 (I +
√ (I ² + K 2)) and the second function
Signal I2 of is expressed by a second function whose combined output with the first signal I1 has a linear relationship.

[0015]

In one example of the present invention, a pair of signals generated in response to an input signal and having phases different from each other by 180 degrees are
A push-pull amplifier that amplifies by the first amplifying means and the second amplifying means having the same characteristics and synthesizes the amplified output as a signal,
The circuit for generating the pair of signals includes a first and a second transistor which have the same polarity and whose bases are connected to each other;
And a second transistor have opposite polarities and have third and fourth transistors whose bases are connected to each other, and the emitters of the first transistor and the third transistor are connected to each other The input signal is connected, and the second
And the emitter of the fourth transistor are connected to each other, and
And the fourth transistor are connected between the collector and the base, respectively, and a current source is connected to the collector of the fourth transistor.
The collector of the transistor is connected to a fixed potential, and the pair of signals is output from the collectors of the first transistor and the third transistor. The input / output characteristics (transfer characteristics) are made non-linear beforehand so that crossover distortion does not occur and the idling current is reduced.

[0016]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of a push-pull amplifier according to the present invention, which is a voltage input-current output power amplifier (conductance amplifier) using a bias circuit 100, and an idling current flowing through output transistors 7 and 10. As in the case of the class A push-pull, there is a characteristic that crossover distortion is not generated in principle even if is suppressed to 1/10 to 1/20 of the maximum output current.

A signal from the signal source 1 (voltage source ei) is amplified by an amplifier 2 having a conductance gm and a current I1
Are supplied to the bias circuit 100. Bias circuit 10
0 is a pair of transistors 101 and 1 having the same characteristics.
02, transistors 103 and 104, and a current source 1
Have 05.

The emitters of the transistors 101 and 103, the emitters of the transistors 102 and 104 are connected to each other, and the bases of the transistors 101 and 102 are connected,
The bases of the transistors 103 and 104 are connected to each other, the emitters and the bases of the transistors 101 and 103 are connected, and the emitters and the bases of the transistors 102 and 104 are connected to each other, and the current I1 from the amplifier 2 is supplied to the emitters of the transistors 101 and 103. Has been done. Also,
The collector and the base of the transistor 101 are connected, and the collector and the base of the transistor 104 are connected. The current source 105 is inserted between the collector of the transistor 104 and the power supply −V, and the power supply + V is connected to the collector of the transistor 102. Transistor 1
The collector of 01 is connected to the emitter of the transistor 5 whose base is connected to the power supply + V, and the collector of the transistor 5 is connected to the power supply + VB via the resistor 3 (R1). On the other hand, the collector of the transistor 103 is connected to the power supply -VB via the resistor 4 (R2).

Thus, currents I1 (+) and I1 (-) having phases different from each other by 180 degrees flow in the resistors 3 and 4 in response to the input current I1. Current I1 (+) and I1
The (-) is amplified by the operational amplifier 6 and the transistor 7 and by the operational amplifier 9 and the transistor 10, respectively, and the currents Io (+) and Io (-) are obtained, and the combined current I of both currents is obtained.
o is the output current. The emitters of the transistors 7 and 10 are connected to the power source + V via resistors 8 and 11, respectively.
B and -VB are connected.

The operation of the bias circuit 100 will be described with reference to FIG. Note that the base current of each transistor is ignored for simplicity. In addition, the transistor 101
Is equal to the characteristic of the transistor 102, and the characteristic of the transistor 103 is equal to the characteristic of the transistor 104.

Now, assuming that the input current Ii is zero in FIG. 2, Io (+) and Io (-) in the figure can be respectively expressed as follows. Io (+) = Is · exp (aV1) (8) −Io (−) = Is · exp (aV3) (9) where Is = reverse saturation current, a = q / kT (q = electron charge, k = Boltzmann constant, T = absolute temperature).

Therefore, V1 + V3 becomes as follows. V1 + V3 = (1 / a ) [ln (-Io (+) · Io (-) / Is 2) ] (10) On the other hand, there is a relation following manner between the bias current Ir, and V2, V4 . Ir = Is · exp (aV2) (11) Ir = Is · exp (aV4) (12) Therefore, V2 + V4 can be expressed as follows. V2 + V4 = (1 / k ) · ln (Ir 2 / Is 2) (13) where, since it is V1 + V3 = V2 + V4 ( 1 / k) [ln (-Io (+) · Io (-) / Is 2) ] = (1 / k) ln (Ir ² / Is ² ) (14) From this, the following relationship is established among Io (+), Io (-), and Ir. −Io (+) · Io (−) = Ir ² (15)

Next, considering the input current I1, Io (-)
= -Io (+) + Since Ii is, equation (15) Io (+) · (Io ( +) - Ii) = Ir 2 (16) , and the following equation is obtained when organizing this. Io (+) ² −Ii · Io (+) − Ir ² = 0 (17) Solving this equation for Io (+) and considering that Io (+) ≧ 0, Io (+) is It is expressed as follows. Io (+) = (1/2) (Ii + √ (Ii ² + 4Ir ² )) (18)

By the way, the input current Ii is equal to Io (+) and Io
Since it is divided into o (−) and Io (+) = Ii−Io (−), Io (−) is given by the following equation. Io (-) = (1/2) (Ii-√ (Ii 2 + 4Ir 2)) (19)

In the equation (4) which is the push-pull linear condition, f (x) = Io (+), f (-x) =-Io
(-), F (x) -f (-x) = Ii,
The right side is a linear expression of Ii, which satisfies the expression (4). Therefore, it can be seen from this that the bias circuit of FIG. 2 according to the present invention performs a linear distortion-free operation when used in a push-pull amplifier.

FIG. 3 shows characteristics of Io (+) and Io (-) and their combined characteristics together with a conventional example (class A push-pull). In the figure, the alternate long and short dash line is the characteristic example of the class A push-pull of the conventional push-pull amplifier, and the thick solid line is the characteristic example of the push-pull amplifier according to the present invention.
A thin solid line is a synthetic characteristic common to the conventional example and the present invention. I
f is the maximum output value, Class A push-pull (dashed line)
In this case, the operating point is If / 2 as shown in FIG.

The feature of the bias characteristics in the present invention is that the bias current (= Ir) at the time of no signal, which is called an idling current and is preferably as small as possible, is greatly reduced as compared with the case of the class A push-pull (the hatched portion in FIG. 3). ) And the efficiency of the bias circuit is improved. Moreover, since the combined characteristic satisfies the linear distortion-free operating condition as described above, good linearity equivalent to class A push-pull can be obtained. In other words, the efficiency of Class B push-pull and A
Combines the linearity of a class push-pull.

With this characteristic, the operating point (that is, the bias point) Ir
Is adjustable, usually 1/10 to 1/2 of output current
Set to 0.

Bias circuit 1 in the embodiment shown in FIG.
Another configuration example of 00 is shown in FIG. FIG. 4 (A)
Eliminates the connection between the collector and base of the transistor 101 of the bias circuit 100 of FIG.
The two collectors and the base are connected together. FIG.
(B) is a transistor 1 of the bias circuit 100 of FIG.
All of the polarities 01 to 104 are replaced with transistors having different polarities. FIG. 4C also shows that the transistors 101 to 104 of the bias circuit 100 of FIG. 4A are all replaced with transistors of different polarities. Thus, PNP and N in the bias circuit
The same effect can be obtained with a circuit in which the PN transistors are replaced.

Further, it is obvious that the transistors connecting the collector and the base as shown in FIGS. 1 and 4A to 4C can be replaced by diodes. At this time, FIG. 4D shows a circuit in which the transistors 102 and 104 in which the collector and the base are connected to each other in the circuit shown in FIG. 4A are replaced with diodes. A circuit in which the transistor in the circuit in FIG. 4C is replaced with a diode is shown in FIG.

Now, in FIG. 4A, the input current Ii
Is zero, Io (+) and Io (-) in the figure can be expressed as follows. Io (+) = Is · exp (aV1) (20) −Io (−) = Is · exp (aV3) (21) where Is = reverse saturation current, a = q / kT (q = electron charge, k = Boltzmann constant, T = absolute temperature).

Therefore, V1 + V3 becomes as follows. V1 + V3 = (1 / a ) [ln (-Io (+) · Io (-) / Is 2) ] (22) On the other hand, there is a relation following manner between the bias current Ir, and V2, V4 . Ir = Is · exp (aV2) (23) Ir = Is · exp (aV4) (24) Therefore, V2 + V4 can be expressed as follows. V2 + V4 = (1 / k ) · ln (Ir 2 / Is 2) (25) where, since it is V1 + V3 = V2 + V4 ( 1 / k) [ln (-Io (+) · Io (-) / Is 2) ] = (1 / k) ln (Ir ² / Is ² ) (26) From this, the following relationship is established among Io (+), Io (-), and Ir. −Io (+) · Io (−) = Ir ² (27)

Next, considering the input current I1, Io (-)
= -Io (+) + Since Ii is, equation (27) is Io (+) · (Io ( +) - Ii) = Ir 2 (28) , and the following equation is obtained when organizing this. Io (+) ² −Ii · Io (+) − Ir ² = 0 (29) Solving this equation for Io (+) and considering that Io (+) ≧ 0, Io (+) is It is expressed as follows. Io (+) = (1/2) (Ii + √ (Ii ² + 4Ir ² )) (30)

By the way, the input current Ii is equal to Io (+) and Io.
Since it is divided into o (−) and Io (+) = Ii−Io (−), Io (−) is given by the following equation. Io (−) = (1/2) (Ii−√ (Ii ² + 4Ir ² )) (31) Therefore, it can be seen that the operation of the circuit of FIG. 4A is the same as that of the bias circuit 100 of FIG. .

The above relationship is similarly applied to FIG. 4 (C). Further, in FIGS. 4A and 4C, the same relationship can be obtained even if the voltage source and the current source are exchanged.

As described above, the signal source 1 is the input signal source of the power amplifier, is applied to the amplifier 2 having the transconductance gm, and its output is the bias circuit 1.
00 is input. At the output of the bias circuit 100, currents Io (+) and Io (-), which are non-linearly converted according to the equations (18) and (19), flow in the resistors 3 and 4, respectively.

The circuit composed of the resistor 3, the operational amplifier 6, the transistor 7 and the resistor 8 and the circuit composed of the resistor 4, the operational amplifier 9, the transistor 10 and the resistor 11 respectively constitute a constant current source circuit, and R0 = R3 = R4, Ri = R1 =
When R2 is set, the bias current (idling current) IB becomes IB = (RO / Ri) Ir (32), and the output current Io becomes Io = gm (Ro / Ri) ei (33).

As described above, when the bias circuit of the present invention is used, the idling current is 5 to 5 times the output current Io.
Even if it is about 10%, the push-pull composition characteristic is guaranteed to be linear. Considering that the idling current in the conventional class A amplifier is required to be 50% of the output current, it can be seen that the efficiency is remarkably improved when the bias circuit of the present invention is used. Further, in addition to the high efficiency, unlike the class B push-pull, since no part of the circuit is cut off, it is possible to avoid the adverse effect due to the minority carrier accumulation, which is a problem in the bipolar transistor. Another advantage is that a wide band can be easily realized.

FIG. 5 shows a second embodiment of the push-pull amplifier according to the present invention, which is applied to a power amplifier having a current mode feedback function and bias circuits 100 and 2 of the present invention.
In this example, 00 is applied. As in the case of FIG. 1, even if the idling current flowing through the output transistors 315 and 319 is suppressed to 1/10 to 1/20 of the maximum output current, crossover distortion does not occur as in the case of class A push-pull. It has features.

The output from the input signal source 301 is applied to an amplifier composed of transistors 302, 303, 308 and 309. One of the outputs of this amplifier (transistor 3
The collector side of 08 is input to the bias circuit 100, and the other output of this amplifier (the collector side of the transistor 309) is also input to the bias circuit 200 similar to the bias circuit 100.

Transistors 302, 303, 308, 3
09 are connected as shown, and transistors 302 and 3 are connected.
The emitter of 03 is connected to the power supplies + Vcc and -Vcc via constant current sources 304 and 305, respectively. Further, the constant current sources 306 and 307 are inserted between the constant current source 304 and the collector of the transistor 308 and between the constant current source 305 and the collector of the transistor 309, respectively.
Thus, the currents Is (+) and Is (-) in the illustrated direction are input to the bias circuits 100 and 200.

Further, a transistor 310, an operational amplifier 313, a transistor 315 and resistors 312 and 314, which further operate in the same manner as the transistor 5, the operational amplifier 6, the transistor 7 and the resistors 3 and 8 of FIG. The circuit includes a circuit 317, a transistor 319, and resistors 316 and 318. Further, a resistor 320 is inserted between the connection point between the collectors of the transistors 315 and 319 and the emitters of the transistors 308 and 309, and a resistor 321 is inserted between the emitter and the ground.

A circuit composed of a resistor 312, an operational amplifier 313, a transistor 315 and a resistor 314, and a resistor 31.
6, operational amplifier 317, transistor 319 and resistor 3
Each of the circuits composed of 18 constitutes a constant current circuit, and a current proportional to the current flowing through the resistors 312 and 316 flows to the output of this constant current circuit and outputs the output Vo.

The output of this circuit is fed back to the emitters of the transistors 308 and 309 via the resistors 320 and 321 as a voltage signal VNF (divided voltage of the resistors 320 and 321), and the output side of the bias circuits 100 and 200, respectively. Are the non-linearly converted currents I1 (+) and I1
(-) Is obtained.

In this embodiment as well, similar to the embodiment shown in FIG. 1, even if the bias current is about 10% of the output current, the push-pull composite characteristic becomes linear. Therefore, while exhibiting efficiency comparable to that of class B push-pull, it exhibits excellent characteristics that crossover distortion does not occur as in the case of class A push-pull.

Further, in addition to the high efficiency, unlike the class B push-pull, no adverse effect due to the minority carrier accumulation, which is a problem in the bipolar transistor, can be avoided because no part of the circuit is cut off. There is also an advantage that high speed and wide bandwidth can be easily realized.

[0047]

By using the bias circuit of the present invention, even if a bipolar transistor is used as the output element of the push-pull amplifier, crossover distortion does not occur in principle as in the case of the class A amplifier. The number can be reduced as compared with a class A amplifier. Therefore, it is possible to realize a low-distortion, high-efficiency amplifier that realizes different requirements of reducing distortion and increasing efficiency. In addition, even though the output efficiency is equivalent to that of class B push-pull,
Unlike Class B push-pull, the circuit does not cut off, so a high-speed and wide-band amplifier can be easily realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a push-pull amplifier according to the present invention.

FIG. 2 is a circuit diagram of a basic part of the embodiment shown in FIG.

FIG. 3 is a diagram for explaining the operation of the embodiment shown in FIG.

FIG. 4 is another configuration circuit diagram of the embodiment shown in FIG.

FIG. 5 is a circuit diagram showing another embodiment of the push-pull amplifier according to the present invention.

FIG. 6 is a circuit diagram of a conventional push-pull amplifier.

[Explanation of symbols]

1,301 Signal source 2 Amplifier 3,4,8,11,312,314,316,318,
320, 321, 510, 513, 514 Resistance 5, 7, 10, 101-104, 201-204, 30
2,303,308 to 311,315,319,50
1,502,508,509,511,512
Transistor 6,9,313,317 Operational amplifier 100,200,500 Bias circuit 105,205,304-307 Current source 106 Voltage source 503-506 Diode 507 Variable resistor

Claims (6)

[Claims] 1. In response to an input signal, the phases are 180 degrees relative to each other.
Signal generating means for outputting a pair of different signals, first amplifying means and second amplifying means for amplifying the respective output signals of the signal generating means, the first amplifying means and the second amplifying means In a push-pull amplifier having a signal synthesizing means for synthesizing respective output signals of the above and extracting a signal to a common load, the signal generating means includes first and second transistors having the same polarity and having their bases connected to each other. , A third transistor having opposite polarities to the first and second transistors and having their bases connected to each other.
And a fourth transistor, the emitters of the first transistor and the third transistor are connected, the input signal is connected to this connection point, and the emitters of the second and fourth transistors are connected. The collector and the base of the first transistor and the fourth transistor are connected to each other, a current source is connected to the collector of the fourth transistor, and the collector of the second transistor has a constant potential. And a pair of signals output from the collectors of the first transistor and the third transistor. 2. In response to an input signal, the phases are 180 degrees relative to each other.
Signal generating means for outputting a pair of different signals, first amplifying means and second amplifying means for amplifying the respective output signals of the signal generating means, the first amplifying means and the second amplifying means In a push-pull amplifier having a signal synthesizing means for synthesizing respective output signals of the above and extracting a signal to a common load, the signal generating means includes first and second transistors having the same polarity and having their bases connected to each other. , A third transistor having opposite polarities to the first and second transistors and having their bases connected to each other.
And a fourth transistor, the emitters of the first transistor and the third transistor are connected, the input signal is connected to this connection point, and the emitters of the second and fourth transistors are connected. The collector and the base of the second transistor and the fourth transistor are connected to each other, a current source is connected to the collector of the fourth transistor, and the collector of the second transistor has a constant potential. And a pair of signals output from the collectors of the first transistor and the third transistor. 3. In response to an input signal, the phases are 180 degrees relative to each other.
Signal generating means for outputting a pair of different signals, first amplifying means and second amplifying means for amplifying the respective output signals of the signal generating means, the first amplifying means and the second amplifying means In a push-pull amplifier having a signal synthesizing means for synthesizing respective output signals of the above and extracting a signal to a common load, the signal generating means includes first and second transistors having the same polarity and having their bases connected to each other. , A third transistor having opposite polarities to the first and second transistors and having their bases connected to each other.
And a fourth transistor, the emitters of the first transistor and the third transistor are connected, the input signal is connected to this connection point, and the emitters of the second and fourth transistors are connected. , The second transistor and the fourth transistor each have a collector and a base connected to each other, a collector of the fourth transistor is connected to a constant potential, and a collector of the second transistor has a current source. Are connected, and the pair of signals are output from the collectors of the first transistor and the third transistor. 4. The push-pull amplifier according to claim 1, 2 or 3, wherein all or part of the transistor connected between the collector and the base is replaced with a diode. 5. In response to an input signal I, the phases are 18 degrees relative to each other.
Signal generating means for outputting a pair of signals different by 0 degrees, first amplifying means and second amplifying means for amplifying respective output signals of the signal generating means, the first amplifying means and the second amplifying means.
In a push-pull amplifier having a signal synthesizing means for synthesizing the respective output signals of the amplifying means and extracting the signals to a common load, a first pull-up circuit comprising the input signal I and a pair of signals from the signal generating means is provided. Of the signal I1 and the second signal I2, the first signal I1 gradually approaches I1 = I as the input signal I increases with respect to a positive value of the input signal I, while
The input signal I is represented by a first function that asymptotically approaches a predetermined constant value for near zero and a negative value, and the second signal I2 is a combined output with the first signal I1. Is represented by a second function having a linear relationship. 6. In response to an input signal I, the phases are 18 degrees relative to each other.
Signal generating means for outputting a pair of signals different by 0 degrees, first amplifying means and second amplifying means for amplifying respective output signals of the signal generating means, the first amplifying means and the second amplifying means.
In a push-pull amplifier having a signal synthesizing means for synthesizing the respective output signals of the amplifying means and extracting the signals to a common load, a first pull-up circuit comprising the input signal I and a pair of signals from the signal generating means is provided. among the signal I1 of the second signal I2, the signal I1 wherein the first and the input signal I, the said input signal I independent of the constant values K1, K2, K1 (I + √ (I 2 +
K2)) and the second signal I2
Is represented by a second function in which the combined output with the first signal I1 has a linear relationship.