JPS6037809A - Complementary class b single ended push-pull amplifier circuit - Google Patents

Abstract

PURPOSE:To hold stably a current flowing to a transistor (TR) of an output stage at no signal by providing each TR between a base and a signal input terminal of two TRs of the drive stage. CONSTITUTION:TRs Q5, Q6 are provided between the base of the two TRs Q3, Q4 of the drive stage and the signal input terminal 11. A constant current source 21, resistors R3-R6 and a constant current source 22 are connected between power supplies +B and -B. An input terminal 11 is connected to a connecting point of the resistors R4, R5 and also the collecter of TRs Q5, Q6 is connected thereto. A voltage VB1 across the resistor R5 is a voltage generated based on the potential difference generated between the base and emitter of the TRQ6 in active state and has a relation of function with a potential difference generated between the base and emitter. The current flowing to the TRs Q1, Q2 of the output stage is held stably at no signal by supplying said potential to the base of the drive stage TRs Q3, Q4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a complementary third-class single endy Dodesh Sol amplifier circuit.

[Technical background of the invention and its problems]

FIG. 1 shows a conventional complementary class B single-ended push-sol amplifier circuit. The signal input terminal 1 is connected to an NPN transistor (4th transistor) and a PNP transistor Qs (3rd transistor) which constitute the drive stage.
(transistor) is commonly connected to the pace of the transistor. The collector of the transistor Q4 (7) is connected to the power source B, and the collector is connected to the power source -B via a resistor R2.

Further, the emitter of the transistor Q3 is connected to the power supply -B via a resistor R, and the collector is connected to the power supply -B. Further, an NPN transistor Ql (first transistor) and a PNP transistor Q2 (second transistor) constituting an output stage are complementary connected between power supplies 1B and -B. That is, the collector of the transistor Qs is connected to the power source 1B, and the conductor is connected to the emitter of the transistor Q3. Also,
The emitter of this transistor Q1 is connected to the signal output terminal 12 and also to the emitter of the transistor Q2. The pace of this transistor Q2 is connected to the emitter of the transistor Q4, and the collector is connected to the power source -B.
connected to.

In the above circuit, in order to extract a large output power, the emitter areas of the output stage transistors Ql and Q2 are often made larger than those of the drive stage transistors Q3 and Q4. However, in this circuit, the collector current of transistors Qt+Qg when there is no signal is equal to the collector currents of transistors Q3 and Q4 and transistor QL.
It is determined by the ratio of the emitter area at IQ2 +Qa and Q4. Here, transistor Qx+Q
Each emitter area of z is transistor Q41Q! 1
transistor Q3.

Letting the collector currents of Q4 be Il and 12, respectively,
The collector current 0 of the transistor Q++Q2 when there is no signal is 10=n, if the base current is ignored. As is clear from the above equation, in the circuit shown in Figure 1, if the emitter area ratio of the output stage transistors Ql and Q2 to the drive stage transistors Q31Q4 is increased, the collector current・Current consumption of the connected circuit increases.

As described above, in the circuit shown in FIG. 1, the current flowing through each transistor and the emitter area ratio cannot be freely set independently, and thus the circuit design is subject to significant restrictions.

Therefore, it is conceivable to set a constant potential difference between the two transistors operating as emitter followers in the drive stage without directly connecting them to the signal input terminals, but with the respective signal input terminals. With this configuration, the current flowing through the output stage transistor when there is no signal can be freely set independently of the current flowing through the drive stage transistor and the ratio of the emitter areas of each transistor. However, with such a configuration, when the temperature changes, an error occurs between the transistor's pace-emitter voltage and collector current, and as a result, the current flowing through the output stage transistor when there is no signal increases. This results in a circuit with poor reproducibility.

[Purpose of the invention]

This invention was made based on the above circumstances, and its purpose is to limit the current flowing through the output stage transistor when there is no signal, the current flowing through the drive stage transistor, and the ratio of the emitter area of each transistor. The present invention is intended to provide an fx complementary BfJ single-ended deso-Sidel amplifier circuit that can be set freely and stably with good reproducibility without any interference.

[Alpha essentials of invention]

This invention provides 1117ij of transistors between each of the paces of the two transistors in the drive stage and the signal input terminal, and in the active state of these transistors, a potential difference having a functional relationship with the potential difference generated between the pace and the emitter is applied. By supplying the current to the drive stage transistor, the current flowing through the output stage transistor during no signal is stably maintained without being affected by temperature changes.

[Embodiments of the invention]

Hereinafter, regarding one embodiment of the present invention, 1nu l'+7+r
See.

I will refer to and explain. Also, same as Figure 1, '1 for 1μ'
Only the different parts will be explained using the same reference numerals.

In FIG. 2, a constant current source 21. Resistor R3r R4r R5r R6+constant current source 2
2 are connected sequentially. Among these, the signal input terminal 11 is connected to the connection point of the resistors R4r and R5, and the collectors of the transistors Qs*Q6 (fifth and sixth transistors) are connected. Of these, the transistor Q and the sno-pace are connected to the pace of the transistor Q4, and also to the connection point of the resistors R3r and R4, and the emitter is connected to the connection point of the constant current source 22 and the resistor R3. Further, the pace of the transistor Q6 is connected to the pace of the transistor Q3, and also to the connection point of the resistors R5+R6, and the emitter is connected to the connection point of the resistor R6 and the constant current source 22.

The operation of the above configuration will be explained. FIG. 3 shows a circuit corresponding to transistor Q6 in FIG. 2. Here, the voltage across the resistor Ets 11 is the pace of the active transistor Q6.

It is a voltage generated based on the potential difference that occurs between the emitters, and has a functional relationship with the potential difference that occurs between the pace and the emitter. This 1. Based on the same principle as the base of transistor Q5.

The voltage across the resistor R4 connected between the collectors is VB2, and the voltage between the transistors Q1+Q21Q3 and Q4 and the emitter is VBEQl1.
VBIQ21VBBQ51VBKQ4 x For these, VBEQ4 vngtax (vIll "82)"
'VBEq1'BEQ2 ``'''' (1) The following relationship holds true.

Therefore, transistors Q4 and Qs in FIG. 2 have the same structure, transistor Q1 has an emitter area n times that of transistor Q4, and transistors Qs and Qs have the same structure.
Assume that the transistor Q2 has an emitter area n times larger than Qs. Furthermore, the transistor Qs
, Q4 collector current ■1+1! and the current generator 3 of the constant current source are all set to be equal to 1, and the resistor R3+
R4+Rs +R6 is Rs/Ra =R4/R3=m
If a value is selected that satisfies the relationship , the collector current flowing through the output stage transistors Q1 + Q2 when there is no signal will ignore the pace current of each transistor, and the forward saturation current of transistors Q31Q4 will be
If sn, then I O= n CISP ・Inn ) n1/2Ir1
−m'=”””(2).As is clear from equation (2), the output stage transistors Q1+Q2
It is possible to change the value of the resistance ratio m without changing the emitter area ratio n of the transistors Q31Q4 in the drive stage or the collector current of the transistor Qs and Q< of the drive stage. It is possible to change the collector current ①o of the transistor.

According to the above configuration, the drive stage transistor Q3,
The potential difference between each pace of Q4 and the signal input terminal 11 is a transistor in an active state. 6.

It is created based on the pace of Qs and the 'rIj level difference generated between the emitters. Therefore, the output stage transistor Q! +Q2 is compensated for temperature changes. Moreover, especially when this circuit is integrated,
Drive stage and output stage transistor Qs lQ4
Even if the relationships between rQs, the pace of Q2, the emitter voltage, and the collector current vary b, the relationships between the reference transistor Qs, the pace of Qs, the emitter voltage, and the collector current also vary in the same direction. Stable and reproducible output stage transistor Q1+Q when there is no signal
2 collector currents can be set.

Next, other embodiments of the invention will be described. Note that the same parts as in FIG. 2 are given the same reference numerals, and only the different parts will be explained.

In FIG. 4, a diode D1 is connected in the forward direction between the connection point between the constant current source 21 and the emitter of the transistor Qli and the resistor R3.

Further, a diode 14D2 is connected in the forward direction between the connection point between the constant current source 22 and the emitter of the transistor Q6 and the resistor R6.

The operation of the above configuration will be explained. FIG. 3 shows a circuit corresponding to transistor Q6 in FIG. 2. Note that the diode D2 is shown surrounding the transistor.

Here, the voltage vB1 across the resistor R5 is a transistor in an active state. The low voltage is generated based on the potential difference generated between the pace and emitter of No. 6, and has a functional relationship with the potential difference generated between the pace and emitter.

Using the same principle, the voltage across resistor R4 connected between the pace and collector of transistor Q5 is set to VB2.
In addition, transistor Q1 lQ2 IQ3
Each pace and emitter voltage of IQ4 is vBEQ.
l “BF+Q21VBEQ31vBEQ4,
Similarly to equation (1), vBEQ4 'EEQ3 (Vsl −VB2)=”
The following relationship holds true: BEQl ``BEQ2 ・R--(3).

Therefore, the transistor in FIG. 4, Qe and D2 have the same structure, transistor Q1 has an emitter area n times larger than transistor Q4, and transistors Q3 and Q5 as well as
The transistor Q2 has an emitter surface n times that of Q3, and it is assumed that the transistor Q2 has an emitter surface n times that of Q3.Furthermore, the collector currents 11+I2 of transistors Q! and Q4 and the constant current source 71 yuan ryuko 3 are all Ir
and the resistance Ra + R4r R
If 5r R6 is selected to a value that satisfies the relationship Rs l R6 = na / R3 = m, the output stage transistor Q1 + Q'2 has a no-signal port (flows to 1), and the collector current 0 is the pace current of each transistor. Io = n Ir/K'' - (4) However, ■( is t+, collector current of transistor Q6 determined by resistance value, and current IdO flowing through resistor R5. The ratio Ic/Id.

As is clear from equation (4), even if the circuit shown in FIG. By changing the resistance values of the resistors R3 to R6 without changing the current value 1, it is possible to change the collector current value 0 of the transistor in the output stage when there is no signal.

Even with such a configuration, the same effects as in the above embodiment can be obtained.

Note that this invention is not limited to the above embodiments,
Of course, various modifications can be made without changing the gist.

〔Effect of the invention〕

As detailed above, according to the present invention, the current flowing through the output stage transistor when there is no signal can be freely and reproducibly controlled by the current flowing through the drive stage transistor or the ratio of the emitter area of each transistor. Therefore, it is possible to provide a complementary class B single-ended double-ended amplifier circuit that can be set easily and stably.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram showing an example of a conventional complementary class B single-ended push-pull amplifier circuit, and FIG. 2 is a circuit configuration diagram showing an example of a complementary class B single-ended push-pull amplifier circuit according to the present invention. Figure 3 is a circuit diagram showing -141 (in Figure 2), Figure 4 is a circuit configuration diagram showing another embodiment of the present invention, Figure 5 is a partial diagram of Figure 4. It is a circuit configuration diagram showing.Ql-Qe...first to sixth transistors, R3-R
6...Resistor, 11...Signal power, )2...Signal output end, 21.22...Constant current source. “Patent Attorney Patent Attorney Suzue Takehiko No. 1” Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A first NPN transistor and a second PNP transistor whose emitters are connected to each other are connected between positive and negative power supplies to operate as two emitter followers, and the collector of the third PNP transistor is connected to the A fourth NPN type transistor is connected to a negative power source and its emitter is connected to the pace of the first transistor, and a collector of an NPN type fourth transistor is connected to the positive power source and its emitter is connected to the pace of the second transistor. A signal is input to the pace of the first transistor and the fourth transistor. In a complementary class B single-ended push-sol amplifier circuit in which a signal is output from the emitter of the second transistor, the collector is connected to the signal input terminal, the emitter is connected to the positive and negative power supplies, and the pace is connected to the fourth transistor.
a fifth connected to the third transistor pace respectively;
．． a sixth transistor; The pace generated when the sixth transistor is in the active state, the potential difference that has a functional relationship with the potential difference between the emitters, is determined by the third and fourth transistors.
A complementary class B single-ended push-pull amplifier circuit characterized by supplying a transistor pace.