JPS62181513A - Transistor circuit - Google Patents

Abstract

PURPOSE:To change the relation in phase of an input/output signal by providing a means connecting the 2nd output terminal of a current mirror in common to a signal output terminal of a collector of a transistor (TR) and obtaining an AC output signal current based on an AC input signal current so as to have only to change the circuit constant. CONSTITUTION:An impedance 8, a TR 4 and an emitter impedance 5 form a current mirror. The resistance of resistors R2, R3, R4 and R5 is selected as R2:R3=R4:R5 so that no DC output is caused and an output terminal 6 in terms of DC by the cancellation of the collector currents of the TRs Q2, 4. Since all components are formed on one semiconductor substrate except a resistor R6 and a capacitor C1 mounted externally, the circuit is suitable for the semiconductor integrated circuit. Further, the AC gain is decided by the impedance comprising the resistor R6 and the capacitor C1 connected to a gain adjustment terminal 12 and the relation of phase between the input and output is selected independently of the DC gain.

Description

[Detailed description of the invention] The present invention relates to the configuration of a transistor amplifier circuit.

Conventionally, various configurations of transistor amplifier circuits have been proposed, but in all cases, a common terminal such as the emitter of the transistor is grounded directly or through a resistor, and a load is connected to the output terminal such as the collector. However, an input signal was applied along with a bias voltage to an input terminal such as a base, thereby obtaining an output to a load. For this reason, even if the amount of input signals, that is, the gain, can be adjusted, it is impossible to change the phase relationship of human input signals. If you dare to change the phase relationship of input and input signals, you can use an inverting amplifier and a non-inverting amplifier, or use a load whose impedance changes depending on the input signal, even in a single-ended push-molar circuit. However, it was similarly not possible to change the phase relationship of input and input signals.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transistor circuit in which the phase relationship between input and input signals can be changed simply by changing circuit constants, and in which the output DC current can be reduced to zero.

The circuit according to the invention comprises a current mirror having a signal input terminal to which an alternating input signal current is supplied together with a bias current, a first and a second output terminal and an input terminal connected to the signal input terminal; impedance means connected between the first output terminal and the potential point, receiving a voltage from the impedance means at its base;
A tiger output terminal with the first resistor connected to the emitter.
and means for commonly connecting a second output terminal of the current mirror and a collector of the transistor to the signal output terminal, so that substantially no direct current is obtained from the signal output terminal, and the alternating current is The present invention is characterized in that an AC input signal current is obtained based on the input signal current.

Since outputs having different phases are generated at the output terminal of the current mirror and the output terminal of the inverting amplifier, the difference between these outputs is obtained as the overall output. Therefore, the phase of the output obtained at the signal output terminal is changed by the current gain of the current mirror and the series circuit of the second resistor and the capacitor, and furthermore, the output DC current is made zero.

Next, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows one embodiment of the present invention. current mirror 2
is a transistor Q whose collector is connected to the output terminal 15 and whose emitter is connected to the power supply 7 via a resistor R, and whose base is connected to the input terminal 14.
, a collector is connected to the output terminal 15, and an emitter is connected to the power supply 7 via a resistor R3. The impedance 8 is a series connection circuit of a resistor R4 and a diode D, and the emitter impedance 5 of the transistor 1 is a series connection of a resistor R5 that determines the DC gain, a resistor R1 that determines the AC gain, and a capacitor C1. It consists of parallel circuits.

In this embodiment, the impedance 8, the transistor 4, and the emitter impedance 5 form a current mirror. These resistances Rt, Rs, R4,
The resistance value of Rw is determined by connecting the resistor R1 and the bias voltage source between the output terminal 6 and the ground in order to give a DC output to the output terminal 6 because the collector currents of the transistors Q and Q cancel each other out and give a bias voltage to the output terminal 6. A series circuit with 8 is provided.

This embodiment is suitable as a semiconductor integrated circuit because only the resistor R0 and the capacitor C+ are externally attached, and everything else can be formed on one semiconductor substrate. At this time, in addition to the power supply terminal and the input/output terminal, it is sufficient to add one gain adjustment terminal 12 taken out from the emitter of the transistor 4 as external terminals. The AC gain can be determined by the impedance of the resistor R6 and the capacitor C1 connected to the gain adjustment terminal 12, and the input/output phase relationship can be set independently of the DC gain.

Another feature is that the output DC voltage depends only on the voltage of the power source 8 and does not depend on the voltage of the power source 7.

Therefore, even if an unregulated power supply or one with large power supply hum is used as the power supply 7, the output will not be affected.

However, the power source 8 can be stabilized.

Next, FIG. 2 shows another embodiment of the present invention.

This is a feedback amplifier in which an amplifier 9 and a feedback element 11 connected between its output terminal 10 and a gain adjustment terminal 12 are added to the amplifier shown in Fig. 1 to form a feedback amplifier. In this example, the closed loop gain is the value obtained by dividing the value of the feedback element 11 by the combined impedance of the emitter impedance 5. , the frequency characteristics can be stuttered if necessary. R, A which is the open loop gain and the gain of transistor 4.

The product of -1 and the gain of the amplifier 9 can be set independently of the resistor R6. By adjusting the value of this resistor R6, the phase of the output can be reversed or the AC output can be made zero. In particular, even if this circuit is implemented as a semiconductor integrated circuit, the embodiment shown in FIG. In particular, the amplifier composed of transistor 4 does not have to have a current mirror configuration, but if it is an inverting amplifier,
Anything is good. Furthermore, the transistors Q, , Q, of the current mirror 2 can be replaced with multi-collector transistors.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the invention, and FIG. 2 is a circuit block diagram showing another embodiment of the invention.

Claims (1)

[Claims] a current mirror having a signal input terminal to which an alternating input signal current is supplied together with a bias current; first and second output terminals; and an input terminal connected to the signal input terminal; the first output terminal of the current mirror; impedance means connected between the impedance means and the potential point, a transistor whose base receives the voltage from the impedance means and whose emitter is connected to a first resistor, and a second resistor connected in parallel to the first resistor. and a capacitor connected in series, a signal output terminal, and means for commonly connecting a second output terminal of the current mirror and a collector of the transistor to the signal output terminal, and a direct current is supplied from the signal output terminal. A transistor circuit characterized in that the AC output signal current is obtained based on the AC input signal current while substantially not being obtained.