JPH01284007A - Phase switching circuit - Google Patents

Abstract

PURPOSE:To switch inversion and noninversion at a high speed and to suppress the deterioration in the characteristic considerably by providing a changeover circuit throwing selectively a constant current source so as to operate either an inverse amplifier or a noninverting amplifier and set the gain of both the amplifiers to the unity. CONSTITUTION:The emitters of differential pair transistors(TRs) are connected in common in a changeover circuit 25 where a constant current source 21 is thrown to an inverting circuit 23 or a noninverting circuit 24 selectively as an inverse amplifier 30 or a noninverting amplifier 40 and are connected to the constant current source 21. Moreover, a base of the TR 11 is used as a control terminal 22 and a constant voltage source 20 is impressed to a base of the other TR 12. Resistors 13-18 of the inverting circuit 23 and the noninverting circuit 24 are set so that the gain of the inverse amplifier 30 and the noninverting amplifier 40 is respectively -1 and +1. Through the constitution above, since the circuit is switched for inversion/noninversion electrically entirely by having only to input a switching signal from the control terminal 22, high speed switching is attained.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a phase switching circuit that can select whether to invert or output an input, and particularly relates to a phase switching circuit with an improved switching means. Its value is high if applied to such things as

[Prior Art] FIG. 2 is an example of a conventionally known phase switching circuit. Mechanical changeover switches 2.5 are provided on signal lines drawn by jumper wires from the input/output ends of the inverting amplifier 3 and the non-inverting amplifier 4 mounted on the printed circuit board, respectively.
By switching the input terminal 1 and the output terminal 6 to either the inverting amplifier 3 or the non-inverting amplifier 4, an inverting or non-inverting output is obtained.

[Problems to be Solved by the Invention] However, since the conventional circuits described above use mechanical switches, high-speed switching is difficult, and since switching is performed by routing signal lines, the signal characteristics This often led to deterioration.

An object of the present invention is to provide a phase switching circuit which eliminates the above-mentioned drawbacks of the prior art by incorporating a switch into an electronic circuit, which enables high-speed switching and which does not cause characteristic deterioration.

[Means for Solving the Problems] The phase switching circuit of the present invention includes an inverting circuit and a non-inverting circuit, and connects their input terminals and output terminals to form a single circuit.

It also has a control terminal, and a switching signal supplied thereto selectively connects the constant current source to an inverting circuit or a non-inverting circuit, and operates either of these as an inverting amplifier or a non-inverting amplifier. The switching circuit can be used to The gains of both the inverting amplifier and the non-inverting amplifier are set to 1.

[Operation] For example, when a switching signal is supplied to the control terminal, the constant current source is connected to the inverting circuit, and the constant current source is activated as an inverting amplifier. Therefore, the input signal input from the input terminal is inverted and output from the output terminal of the inverting amplifier.

Further, when the supply of the switching signal is cut off, the constant current source is connected to the non-inverting circuit, and this is brought into operation as a non-inverting amplifier. Therefore, the input signal is output from the output terminal of the non-inverting amplifier in a non-inverted state.

The amplitudes of these inverted and non-inverted outputs are equal to the amplitude of the input signal since the gains of both amplifiers are both set to 1.

[Example code] FIG. 1 shows an embodiment of the phase switching circuit of the present invention.

In the inverting circuit 23, the emitter of the differential pair transistor 7°8 is connected to the switching circuit 25 via the emitter resistor 15.16.
Connect to. Further, the collector is connected to the power supply element V via load resistors 13 and 14.

In the non-inverting circuit 24, a differential pair transistor 9.10
The emitter of is connected to the switching circuit 25 via resistors 17 and 18. Also, a load resistor 13.1 common to the inverting circuit 23
The collector is connected to the common power supply V through 4.

The base of one transistor 9 of the non-inverting circuit 24 and the base of one transistor 7 of the inverting circuit 23 are commonly connected, and the common connection point is used as the input terminal 1.

Further, the base of the other transistor 10 of the non-inverting circuit 24 is connected to the base of the other transistor 8 of the inverting circuit 23, and a common constant voltage source 19 is applied thereto. Further, the common point between the collector of one transistor 7 of the inverting circuit 23 and the collector of the other transistor 10 of the non-inverting circuit 24 is the output terminal 6.

On the other hand, the constant current source 21 is connected to the inverting circuit 23 or the non-inverting circuit 2
In the switching circuit 25 that selectively connects the differential pair transistors 11 and 4 to the inverting amplifier 30 or the non-inverting amplifier 40, the emitters of the differential pair transistors 11 and 12 are commonly connected and connected to the constant current source 21.

In addition, the collector of one transistor 11 is connected to the inverting circuit 2.
The other transistor 1 is connected to the connection point of the resistors 15 and 16 of transistor 3.
2 are connected to the connection points of the resistors 17 and 18 of the non-inverting circuit 24, respectively. And one transistor 1
The base of transistor 1 is used as a control terminal 22, and a constant voltage source 20 is applied to the base of the other transistor 12. Note that only one constant current source 21 is required here because it is commonly used, but the inverting circuit 23 and the non-inverting circuit 2
It is also possible to separately prepare a constant current source for 4 to make the number two.

The values of the resistors 13 to 18 of the inverting circuit 23 and the non-inverting circuit 24, which are connected to the constant current source 21 and forming the inverting amplifier 30 and the non-inverting amplifier 40, are such that the gains of the inverting amplifier 30 and the non-inverting amplifier 40 are -1, respectively. , +1.

Now, in the above configuration, when a voltage higher than that of the constant voltage source 20 is applied as a switching signal to the control terminal 22 of the switching circuit 25, the transistor 11 is turned on and the transistor 12 is turned off.

Therefore, the constant current source 21 is connected to the inverting circuit 23, the inverting port #123 operates as the inverting amplifier 30, and the non-inverting circuit 24 becomes inactive.6 Therefore, the signal input to the input terminal 1 is connected to the inverting amplifier 30. 30 and is inverted and output from the output terminal 6.

Conversely, when a voltage lower than that of the constant voltage source 20 is applied to the control terminal 22, the transistor 11 is turned off and the transistor 12 is turned on. Therefore, the constant current source 21 is connected to the non-inverting circuit 24, the non-inverting circuit 24 operates as a non-inverting amplifier 40, and the inverting circuit 23 becomes inactive. Therefore, the signal input to the input terminal 1 is transmitted to the non-inverting amplifier 4.
o and output from the output terminal 6 in a non-inverted state.

In this way, according to the present embodiment, switching between inversion and non-inversion can be performed electronically by simply inputting a switching signal to the control terminal 22, thereby enabling high-speed switching. Also, the gains of the inverting amplifier 30 and the non-inverting amplifier 40 are set to −1, respectively.
, +1, characteristic deterioration can be suppressed to an extremely low level and high reliability can be obtained.

[Effects of the Invention] According to the present invention, a switching circuit that selectively connects a constant current source is provided to operate either an inverting amplifier or a non-inverting amplifier, so that conventional machines can be operated. It is possible to switch between inversion and non-inversion at a much higher speed compared to automatic switching.

Further, since the switching is performed in a circuit manner and the gains of both amplifiers are set to 1, deterioration of characteristics can be significantly suppressed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the phase switching circuit of the present invention, and FIG. 2 is a circuit diagram showing a conventional example. In the figure, 1 is an input terminal, 6 is an output terminal, 21 is a constant current source,
22 is a control terminal, 23 is an inverting circuit, 24 is a non-inverting circuit,
25 is an inverting IIA circuit, 30 is an inverting amplifier, and 40 is a non-inverting amplifier.

Claims (1)

[Claims] 1. It has an inverting circuit and a non-inverting circuit whose input terminals and output terminals are commonly connected, respectively, and a control terminal, and a constant current source is selectively connected to the inverting circuit or the non-inverting circuit by a switching signal supplied to these. A phase switching circuit comprising a switching circuit for operating either one of these as an inverting amplifier or a non-inverting amplifier, and the gains of both the inverting amplifier and the non-inverting amplifier are set to 1.