JPS60103815A - Operational amplifier - Google Patents

Abstract

PURPOSE:To extract two non-inverting and inverting outputs to the same input by constituting a bias generating section, a differential section and a couple of amplifier sections with CMOS circuits, applying one output of the differential section to one amplifier section and applying the other output of the differential section to the other amplifier section. CONSTITUTION:The 1st and 2nd amplifiers 20, 21 are provided to the differential section 13 and the 1st amplifier 20 consists of an N-channel transistor (TR)23 to which a power supply Vdd is fed via a P-channel TR22. Furthermore, the 2nd amplifier section 20 consists of an N-channel TR25 to which the power supply Vdd is fed via a P-channel TR24. Then the signals from differential output lines A and B of the differential section 13 is fed to each gate of the TRs 23 and 25. Phase compensation capacitors 28, 29 are connected respectively to the TRs 23 and 25, and a non-inverting output signal (+) and an inverting output signal (-) are extracted respectively from output terminals 26 and 27.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an operational amplifier constructed of a CMO3 integrated circuit and also used as a comparator.

[Technology behind the invention and its problems] The operational amplifier composed of CMO8 integrated circuits is a normal quantity)
Consists of one j terminal. Therefore, when trying to extract two outputs with opposite phases for the same input signal,
It is necessary to use a combination of two operational amplifiers. Therefore, using two operational amplifiers in this way not only complicates the circuit configuration, but also increases the number of operational amplifiers used.
If the characteristics of the operational amplifiers must be exactly matched,
This is a situation in which the characteristics of the two forward and reverse phases do not match.

[Purpose of the Invention This invention was made in view of the above points.
1 i[! composed of 08 circuits. It is an object of the present invention to provide an operational amplifier in which positive-phase and reverse-phase output signals can be obtained using the same input signal using the integrated circuit of (a).

[Summary of the Invention] In other words, the operational amplifier according to the present invention constitutes a pair of amplification sections together with a bias light generation section and a differential section using the 0M08 circuit, and supplies the output of one of the differential sections to the one amplification section. However, the other output of the differential section is supplied to the other amplifier section, so that two outputs of positive 4 fJ and reverse phase can be obtained for the same human power.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows its configuration, and this operational amplifier has 0
It is constituted by an integrated circuit using MO8. This operational amplifier includes a differential section 13 composed of a pair of P-channel transistors 11 and 11.12, and input terminals 14 connected to electrodes of the pair of transistors 1 and 11.12, respectively. .15 are supplied with input signals (+) and (-) of positive polarity and negative polarity, respectively. In addition, for the transistors 11 and 12, the P channel 1-transistor 1, which constitutes a bias generation section whose gate is controlled by the constant current source 16, is connected to the transistors 11 and 12.
A positive power supply Vdd is connected through 7, and a negative power supply Vss is connected through N-channel transistors 18 and 19, respectively. Differential output lines A and B are connected to the transistors 11 and 12, respectively.
A differential output signal is extracted from each of them.

The differential section 13 configured in this manner is provided with first and second amplifiers 20 and 21, and the first
The amplifier 20 is an N-channel transistor 1-transistor 2 which is supplied with a power supply Vdd via a P-channel transistor 22.
Consisting of 3. In addition, the second amplifier 20 has P
It is constituted by N channel 1 to transistor 25 which are supplied with power Vdd via channel transistor 24, and the source electrodes of each of the L transistors 23 and 25 are connected to power VSS. Then, the signals from the differential output lines A and B of the differential section 13 are supplied to the gate electrodes of the i-transistors 23 and 25, respectively.
A positive phase output signal (+) and a negative phase output signal (-) are taken out from the output terminals 26 and 27 connected to the drain electrodes of 5, respectively.

Here, phase compensation capacitors 28 and 29 are connected between the drain electrodes and Goomill electrodes of the transistors 23 and 25, respectively.

That is, when an output signal is generated on one differential output line B of the differential section 13 in response to an input signal (+> (-)) to the input terminals 14 and 15, the second amplifier 2
The transistor 25 of No. 1 is now operated by the signal from the line B, and an opposite phase output is obtained from the output terminal 27. Now, the negative side is connected to the (-) input terminal 15,
If a positive input signal is input to the (+) input terminal 14, then the line B is raised to the positive side, which causes the transistor 25 to be strongly turned on, and a negative voltage is output from the output terminal 17. will now be output.

In this state, the (-) input terminal 15 is facing forward and the (
+) When the polarity of the input signal changes so that it goes in the negative direction at the input terminal 14, the potential of line B gradually changes in the negative direction, and the transistor 25 becomes weakly turned on. In this state, the output terminal 17 generates an output signal of negative voltage. Then, when the input signal levels of input terminals 14 and 15 become the same, the potential of line B becomes the limit value of the ON state of transistor 15, and this transistor 15 is in an extremely weak ON state, and the output terminal 27 outputs the ground potential. I come to do it.

Then, the state of change of this input signal further progresses, and (-)
The input terminal 15 of (10) is on the positive side, and the input terminal 14 of (10) is the positive side.
When becomes negative, the potential of line B becomes negative, and transistors 1 to 25 are turned off. Therefore, the output terminal 27 outputs a positive voltage signal. If the polarity of the input signal to the input terminals 14, 15 is further reversed from this state, the above-described operation proceeds in the reverse state, and the initial state is returned.

That is, the output terminal 27 of the operational amplifier generates an output signal having a phase opposite to that of a normal operational amplifier. In this case, a potential with a polarity opposite to that of line B is generated on line A depending on the polarity state of the input signal, and the transistor 23 controlled by the potential of line A generates a potential at the other output terminal. The polarity of the output signal from 2G is determined. In other words, this output terminal 2G
, an output signal with a polarity opposite to that of the output signal from the output terminal 27 can be obtained, and the polarity of the output signal from the output terminal 2G is the same as that of the conventional operational amplifier. Corresponds to polarity.

If the operational amplifier circuit shown in FIG. 1 is configured to remove capacitors 28 and 29, it can be used as a comparator as is.

FIG. 2 shows a circuit of still another embodiment, in which the differential section 13 is composed of N-channel transistors 31 and 32,
<+) and (-) input signals are coupled to the gate electrodes of transistors 1 to 31 and 32, respectively. The output terminals 35.3 are configured to drive output P-channel transistors 33.34, and output terminals 35.3.
The <+) and (-) output signals are extracted from G. However, for the embodiment shown in FIG.
It is also possible to configure the structure in such a manner that the transistors can be replaced. Also, for this circuit, the same state as in FIG.
It is also possible to construct an operational amplifier by inserting a capacitor between each of them.

[Effect of the invention] As described above, according to this invention, fv of a very simple circuit
By adding I, it is possible to generate arithmetic output signals of positive phase and negative phase for the same input signal.
This makes it possible to obtain a single integrated circuit using MO8, that is, a single-chip operational amplifier, which can be highly effective when configuring various control circuits and the like.

[Brief explanation of the drawing]

The first section is a circuit diagram showing an operational amplifier according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing another practical example of the present invention. 11.12...P channel 1~ransistor, 13.
...Differential section, 14.15...Input terminal, 2o, 21.
...Amplification section, 23.24...N channel 1 to transistor, 26.27...Output terminal. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] a differential section made up of a CMOS circuit to which two input signals are supplied; a first amplification section made up of a CMOS circuit to which one output from the differential all is supplied; and a second amplifying section to which the output of the other of the two amplifying sections is supplied, and output J signals of normal phase and negative phase are extracted from the first and second amplifying sections, respectively. operational amplifier.