JPS6046851B2 - transistor circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor circuit suitable for application to gain control circuits, multiplier circuits, switching circuits, etc., and aims to propose a transistor circuit that is capable of stabilizing its operation.

An example of the transistor circuit of the present invention will be explained below with reference to the drawings.

FIG. 1 shows a basic embodiment of the transistor circuit of the present invention.

The collector of the first transistor Q is connected to one end of the power supply +B (
The other end is grounded), its base is connected to one end of the reference bias power supply +Br (the other end is grounded), and its emitter is connected to the base of the second transistor Q2. It is grounded through a first current source IK. The collector of the second transistor Q2 is connected to one end of the power supply +B, and the emitter of the third transistor Q2 is one of the transistors forming the differential circuit DK.
3 and a second current source IK. grounded through. The base of the fourth transistor Q4, which is the other transistor constituting the differential circuit DK, is connected to the emitter of the fifth transistor Q5, and the third and fourth transistors Q, , Q. The emitter of is a constant current source IK. grounded through. The collector of the fifth transistor Q5 is connected to one end of the power supply +B, and its emitter is connected to the third current source IK. The base of the transistor Q3 is connected to the collector of the third transistor Q3, and to one end of the reference bias power supply +Br via the transistor Q6 which operates as a diode. Note that in order to operate the transistor q as a diode, the base and collector are connected to the reference bias power supply +Br.
The same operation is performed when connected to B. Furthermore, the differential circuit D
K is provided with a load L, and in this example, the load L is connected between the collector of the fourth transistor Q4 and the power supply. In this circuit, one of the first and second current sources is controlled by the first signal, and the other of the first and second current sources or the third current source is controlled by the second signal. do.

Furthermore, this circuit is composed of, for example, an IC, and the transistors Q1-q are made to have the same characteristics.

The voltage of reference bias power supply +Br is connected to Erl transistor Q
The base-emitter voltage of 1 to Q6 is Vbe, ~Vbe
6, the following equation holds true. By transforming equation (1), the following equation is obtained. Here, assuming that the HFE of the transistor Q3 is sufficiently large and assuming that the collector current and emitter current of the transistor Q3 are approximately equal, the following equation holds true.

However, when formula (3) is substituted for formula (2), the emitter currents 11, 12, 14, and 15 of each transistor Ql, Q2, Q4, and Q5 have a saturation current ISl.
If the electron charge is q1, the Boltzmann constant is k1, and the absolute temperature is T degrees, it is expressed by the following formula.

Since Exp and >1, equations (5) to (8) can be expressed as follows by further transforming .beta.Bel, .beta.Be2, .beta.Be4, and Vbe5 as follows.

Next, convert equations (13), (14), (15), and (16) into (
4) When rearranged by proxy, it can be expressed as equation (17).

From equation (17), 1112=1415 Therefore, the first current source 1K1 is controlled by the first signal, that is, the input signal is superimposed on the emitter current 11 of the transistor Q1, and the emitter current 12 of the transistor Q2 or the emitter current 12 of the transistor 9 is By changing either one of the emitter currents 15, a gain control amplifier circuit can be constructed.

In addition, the first current source 1K1 and the second current source 1K2 are controlled by independent first and second signals, that is, the emitter current 11 of the transistor Q1 and the emitter current 12 of the transistor Q2 are controlled independently. By superimposing the signals, a frequency conversion circuit using a multiplier or a switching detection circuit can be constructed.

Further, this circuit is configured so that a negative feedback effect is performed by the transistor Q5, and the operation is stabilized together with the configuration of the differential amplifier circuit DK.

That is, when the collector current of the transistor Q4, which is the load current, attempts to increase, the collector current of the other transistor Q3, which constitutes the differential amplifier circuit DK as the transistor α, decreases. As a result, the collector current of transistor Q5 decreases, and the collector current of transistor Q4, that is, the load current tends to decrease. Next, an example in which the transistor circuit of the present invention is applied to a gain control amplifier circuit will be explained with reference to FIG.

In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and redundant explanation will be omitted. In the circuit shown in FIG. 2, the constant current source circuits 1K1 and IK291K491K5 in FIG. 1 are constructed from transistors Q79Q89Q99QlO and the like. That is, the emitter of transistor Q1 is connected to the collector of transistor Q7, its base is grounded via a series circuit of signal source V1 and battery E1, and its emitter is grounded via resistor R1. The emitter of transistor Q2 is connected to the collector of transistor Q8, the base of which is connected to a battery E that can vary the voltage.
2 and its emitter is grounded through resistor R2. The emitter of transistor Q3 is connected to the collector of transistor Q9, its emitter is grounded through resistor R3, and its base is connected to resistors R5, R6.
connected to the connection midpoint of The base of transistor Q4 is connected to the collector of transistor QlO, its emitter is grounded via resistor R4, and its base is connected to the midpoint between resistors R5 and R6. Also, resistor R5,
R6 and R7 are connected between the power supply and ground, and resistor R7
, R6 are connected to the base of transistor Qll, their collectors are connected to the power supply +B, and their emitters are connected to the base of transistor Q1 and to the collector and base of transistor Q6. Then, a reference voltage Er is obtained at the emitter of the transistor Qll. Also, the collector of transistor Q4 and the power supply +B
A load resistor R8 is inserted between the transistor α
The collector of is connected to the output voltage terminal VOut. Second
In the gain control amplifier circuit shown in the figure, the transistor Q
By superimposing the current based on the signal source V1 on the emitter current 11 of the transistor Q1 and changing the voltage of the battery E2, the emitter current 12 of the transistor Q2 is changed and the current is increased upstream (17
), the magnitude of the emitter current 14 of the transistor α is controlled, and the output voltage obtained across the load resistor R8 is controlled. Next, an example in which the transistor circuit of the present invention is applied to a multiplication circuit or a frequency conversion circuit will be explained with reference to FIG.

In FIG. 3, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and redundant explanation will be omitted. In the circuit shown in FIG. 3, the base of transistor Q8 in FIG. 2 is grounded through a series circuit of signal source V2 and battery E2. That is, in the multiplication circuit or frequency conversion circuit shown in FIG. 3, currents based on independent signal sources Vl and V2 are superimposed on the emitter currents 11 and 12 of transistors Ql and Q2, respectively,
As can be understood from equation 17), the emitter current L of the transistor Q4 is changed by the signals from the signal sources Vl and V2. The output voltage obtained across the load resistor R8 is controlled by arbitrarily set signals from the signal sources V1 and 2, and the circuit shown in FIG. 3 operates as a multiplication circuit or a frequency conversion circuit. Next, an example in which the transistor circuit of the present invention is applied to a balanced frequency conversion circuit will be explained with reference to FIG.

In FIG. 4, parts corresponding to those in FIG. 3 will be described with the same reference numerals. The circuit shown in FIG. 4 is a circuit in which a circuit made up of transistors Q11-Q2O having substantially the same circuit configuration as the circuit made up of transistors Q1-Q1O shown in FIG. 3 is connected in parallel. Transistor Q1~
The transistors corresponding to QlO are sequentially numbered Qll to Q2O. The emitter of transistor Q1 is then connected to the collector of transistor Q7, the emitter of which is connected to the collector of transistor Q32 via resistor R1, and the base of which is connected to the first signal source V2 via capacitor C2. It is also grounded via resistor R9 and battery E1.

The emitter of transistor Q2 is connected to the collector of transistor q, its emitter is connected to the collector of transistor Q3l via a resistor R2, its base is connected to the second signal source V1 via a capacitor C1, and It is grounded via the resistor RlO and the battery E2. On the other hand, the emitter of transistor Q2l is
7 and its emitter is connected to the resistor R2l
is connected to the collector of the transistor Q32 through the capacitor C22, and its base is connected to the first signal source V1 through the capacitor C22.
and grounded via resistor R29 and battery E2l. Transistor Q2. is connected to the collector of transistor Q28, whose emitter is connected to the collector of transistor Q3l via resistor R22, whose base is connected to the second signal source V2 via capacitor C2l and to the collector of transistor Q3l. Battery E22
grounded through. Further, resistors R7, R6, R5, and R33 are connected in series between the power supply +B and the ground, and the midpoint between the resistors R5 and R33 is the transistor Q3l,
connected to the base of Q32, and the respective emitters are connected to the resistor R
3l and grounded via R32. Next, let us explain the operation of the circuit described above.

Now, the collector current of transistor Q7 is 11+Δ11,
The collector current of transistor Q8 is 12 + Δ12, the collector current of transistor Q7 is 11 - Δ11, and the collector current of transistor Q28 is 12 - Δ12 (however, Δ11
, Δ12 are the amounts of change in the currents 11 and 12 due to the first and second signal sources Vl and V2). Here, the current 10ut flowing through the load resistor R8 is represented by the sum of the currents 14 and 124, and the current ! is expressed as \y) - 15 according to equation (18), so the fourth
In the case of the figure, it is expressed as fortune teller A C9A, and the current 124 is similarly L and expressed as Saratsuji A fortune χ5=~a.

・10ut is L (512
Since it is the sum of 4, IOut is expressed as.

Therefore, if signals of appropriate frequencies are supplied from the first and second signal sources Vl and V2 in the circuit shown in FIG.
For load current 10ut, current Δ1 due to signal sources Vl and V2
1, Δ12 product component is obtained.

The circuit shown in FIG. 4 is compared with the circuit shown in FIG.
Since the first and second signal sources are inserted in a balanced manner rather than unbalanced, and the load current 10 ut is also represented by the sum of 14 and 124, signals of appropriate frequencies are generated from the signal sources Vl and V2. This circuit operates as a fully balanced frequency conversion circuit. Thus, according to the transistor circuit of the present invention, the circuit configuration includes transistors Q3 and Q.
4 (and transistors Q23 and Qu), the circuit operation can be stabilized.

Further, since the transistor Q5 (and the transistor Q25) constitute a negative feedback circuit, the circuit operation becomes more stable. Furthermore, the transistor circuit of the present invention can be easily constructed using an IC (semiconductor integrated circuit).

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the transistor circuit of the present invention, FIG. 2 is a circuit diagram showing an example of applying the present invention to a gain control amplifier circuit, and FIG. 3 is a circuit diagram showing an example of applying the present invention to a multiplication circuit or a frequency conversion circuit. FIG. 4 is a circuit diagram showing an example in which the present invention is applied to a balanced frequency conversion circuit b. Q1 to Q5 are first to fifth transistors, DK is a differential circuit, and IKl to IK3 are first to third current sources.

Claims (1)

[Claims] 1 The collector of the first transistor is connected to one end of the power supply, the emitter thereof is connected to the base of the second transistor, and the other end of the power supply is connected through the first current source, and the base is connected to the reference bias. The collector of the second transistor is connected to one end of the power supply, the emitter of the second transistor is connected to the base of a third transistor which is one transistor constituting a differential circuit, and the second transistor is connected to one end of the power supply. The base of a fourth transistor, which is the other transistor constituting the differential circuit, is connected to the other end of the power supply through a current source, and the collector of the fifth transistor is connected to the emitter of the fifth transistor. the third transistor is connected to one end of the power source, the emitter of which is connected to the other end of the power source through a third current source, and the collector of the third transistor is connected to the base of the first transistor through the emitter-base of a sixth transistor; The base of the fifth transistor is connected to a connection point between the collector of the third transistor and the emitter of the sixth transistor, and the emitters of the third and fourth transistors are connected to a fourth current source. is connected to the other end of the power supply through the differential circuit, and a load is connected to the differential circuit, and one of the first and second current sources is controlled by the first signal, and A transistor circuit characterized in that the other of the current sources or the third current source is controlled by a second signal.