CN1024880C

CN1024880C - Linear amplifier

Info

Publication number: CN1024880C
Application number: CN 91104865
Authority: CN
Inventors: 黄勤
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-07-16
Filing date: 1991-07-16
Publication date: 1994-06-01
Anticipated expiration: 2006-07-16
Also published as: CN1068921A

Abstract

The present invention relates to an amplifier with local negative feedback. A local negative feedback network with the characteristic of high pass filtering realizes the reconstruction of zero poles, so the present invention simultaneously has good dynamic performance and steady-state performance, namely high band width, high rising speed and high gain. In a new self-stabilizing zero type operational amplifier, an active stable zero capacitor is arranged in the input circuit of the amplifier, and an auxiliary amplifier can counteract voltage on the active stable zero capacitor and the null shift of the input circuit, so the amplifier lies in the state of normal amplification whatever the stage the amplifier exists in. Therefore, the present invention has the advantages of little interference, low noise, continuous amplification of input signals and no influence on the operating frequency or the dynamic performance of the amplifier. The circuit is simple and is easy for integrated large-scale production, so the circuit is suitable for both common occasions and occasions of aerospace, etc. with high requirements.

Description

Linear amplifier

The present invention relates to a kind of steady certainly zero molded lines amplifier, refer to operational amplifier and OCL power amplifier especially.

Typical prior art is to obtain copped wave that the many integrated circuits factory of extensive use produces from steady zero type operational amplifier, the 5G7650 type operational amplifier of producing as Shanghai element five factories.Sort circuit has a surely pair passage of zero, it is unstable zero the time to pay passage, pay passage through capacitor steady zero the amplification of a warp is provided input signal amplify to the main channel, it is steady zero the time to pay passage, the input signal that utilizes capacitor to keep amplifying, amplify for the main channel, realize steady zero of input signal with this.Because when pair passage was surely zero, capacitor was to keep attitude, so the amplifier frequency of utilization is subjected to the restriction of chopper-zero-stabilized frequency, dynamic property is affected, because the voltage of capacitor is relevant with input signal, it is big to discharge and recharge intensity, so sort circuit has stronger impact interference and noise.

The purpose of this invention is to provide a kind of linear amplifier, its impact to disturb little, noise is low, can be from steady zero reducing the drift of amplifier greatly, and do not influence the operating frequency and the dynamic property of amplifier again.

Invention is achieved in that from steady zero type amplifier first, second two inputs and an output.The main amplifier that first, second two inputs and an output are arranged, between its first input end and steady certainly zero type amplifier first input end first loop of containing main steady zero capacitance device is arranged, second input of main amplifier and output have path to constitute second input and the output of steady zero type amplifier certainly respectively.When the first input end of main amplifier is that positive input terminal second input is that negative input end is that positive input terminal second input is a negative input end from the first input end of steady zero type amplifier then, when the first input end of main amplifier is that negative input end second input is that positive input terminal is that negative input end second input is a positive input terminal from the first input end of steady zero type amplifier then.Have one to be used for steady zero the very little booster amplifier of drift, it has positive and negative two inputs and an output.The positive-negative input end of booster amplifier, output and second, third that contain switch, the 4th loop are arranged respectively between the first input end of the one the second inputs of steady zero type amplifier, main amplifier, switch can be as analog switch, the switch of relay switch class, preferably analog switch.Booster amplifier is to when steady zero type amplifier is surely zero, second, third, the switch in the 4th loop all connects, the output of booster amplifier changes the voltage on the main steady zero capacitance device, make it to offset with the drift of input circuit, make the drift between the one the second inputs of steady zero type amplifier very little, depend primarily on the drift of booster amplifier, like this, realized steady zero of steady certainly zero type amplifier.Booster amplifier does not need steady zero the time from steady zero type amplifier, and the switch in the 4th loop disconnects, because the voltage maintenance effect of main steady zero capacitance device, the drift between the one the second inputs of steady zero type amplifier will be very little still.Above-mentioned two states can hocket, and also can have only first kind of state.No matter in what, main amplifier is in normal magnifying state always in stage, therefore, can realize amplifying continuously to input signal, and state exchange is to from steady zero type amplifier frequency characteristic and not influence of dynamic property.

Of the present invention further describing in conjunction with providing with next embodiment and accompanying drawing.

Fig. 1 is circuit theory diagrams of the present invention.

First, second two inputs [4 are arranged, 5] and the main amplifier [A1] of an output [6], its first input end [4] and between steady zero type amplifier first input end [1] first loop of containing main steady zero capacitance device [C1] is arranged, second input [5] of main amplifier [A1] and output [6] are respectively as second input [2] and output [3] from steady zero type amplifier.The positive-negative input end [7 of booster amplifier [A2], 8], output [9] and from the one the second inputs [1 of steady zero type amplifier, 2], have respectively by analog switch [S1 between the first input end [4] of main amplifier [A1], S2, S3] form second, the 3rd, the 4th loop, booster amplifier [A2] is to when steady zero type amplifier is surely zero, second, the 3rd, switch [the S1 in the 4th loop, S2, S3] all connect, the output of booster amplifier [A2] changes the voltage on the main steady zero capacitance device [C1], make it to offset with the drift of input circuit, make the drift between the one the second inputs [1,2] of steady zero type amplifier very little, depend primarily on the drift of booster amplifier, like this, realized steady zero of steady certainly zero type amplifier.

Booster amplifier [A2] can be surely zero to self.It meets amplifier [A3] and the analog switch [S4 of an auxiliary capacitor [C2] before by a negative input end, S5, S6] form, one of auxiliary capacitor [C2] is terminated at the negative input end of amplifier [A3], the other end is as the negative input end [8] of booster amplifier [A2], the positive input terminal of amplifier [A3], output corresponds respectively to the positive input terminal [7] of booster amplifier [A2], output [9], between the positive input terminal of amplifier [A3] and a reference point [10] the 5th loop of being made up of analog switch [S4] is arranged, between end [8] that auxiliary capacitor [C2] does not link to each other with the negative input end of amplifier [A3] and above-mentioned reference point [10] the 6th loop of being made up of analog switch [S5] is arranged, the negative input end of amplifier [A3] and output have the 7th loop of being made up of analog switch [S6].Described reference point [10] can be earth terminal (an accompanying drawing with dashed lines line), also can be the end [11] (accompanying drawing solid line line) that main steady zero capacitance device [C1] does not link to each other with main amplifier [A1] first input end [4].Do not have steady certainly zero type amplifier in the steady zero time at booster amplifier [A2], booster amplifier [A2] can be surely zero to self, at this moment, the switch [S2] of the switch in second loop [S1], tertiary circuit, the switch [S3] in the 4th loop all disconnect, the switch [S5] in the switch in the 5th loop [S4], the 6th loop, the switch [S6] in the 7th loop are all connected, amplifier [A3] is connected into voltage follower, floating of voltage on the auxiliary capacitor [C2] and amplifier [A3] zero offset, and finishes steady zero of booster amplifier [A2].To when steady zero type amplifier is surely zero, above-mentioned switch switching situation is opposite at booster amplifier [A2], that is: S1～S3 all connects, and S4～S6 all disconnects.Can realize having very little drift to self steady booster amplifier [A2] of zero.

Above-mentioned first loop also can have a linear amplifier [A4] that is connected into the voltage follower form to be connected between the first input end [1] of leading steady zero capacitance device [C1] and oneself steady zero type amplifier, its positive input terminal links to each other with first input end [1] with steady certainly zero type amplifier, and an end [11] of negative input end, output and main steady zero capacitance device [C1] joins.Voltage follower [A4] can reduce the output resistance of signal, reduces the interference of main steady zero capacitance device [C1] charging and discharging currents to input signal, and here it must not have, when particularly the internal resistance of input signal source is very little.

Amplifier [A1, A3, A4] preferably has high input impedance, makes the operational amplifier of input stage as adopting field effect transistor, and desirable 0.01～10 μ F of capacitor [C1, C2] requires electric leakage little, the best Ron of analog switch＜500 Ω, Roff＞1000M Ω.

Also has clock circuit [12] among the figure, it provides control signal for each analog switch [S1～S6], its available common multivibrator and NAND gate circuit are formed, the control signal that is sent to switch [S1～S3] is the relation of logic NOT with the control signal that is sent to switch [S4～S6], and the level of control signal is just determining the break-make of analog switch.

Sort circuit of the present invention, reached the purpose of invention, and circuit is simple, realization is easy, performance is good, be easy to integrated large-scale production, structurally guaranteed main and auxiliary help influence each other between amplifier little, circuit working guarantees stable easily, both has been applicable to common occasion, also is applicable to high request occasions such as Aero-Space.

Claims

1, a kind of linear amplifier, especially refer to operational amplifier and OCL power amplifier, it can be from steady zero, it is characterized in that: this linear amplifier has first, the second two inputs [1,2] and an output [3], have first, the second two inputs [4,5] and the main amplifier [A1] of an output [6], between its first input end [4] and steady certainly zero type amplifier first input end [1] first loop of containing main steady zero capacitance device [C1] is arranged, second input [5] of main amplifier [A1] and output [6] have path to constitute second input [2] and the output [3] of steady zero type amplifier certainly respectively, when the first input end [4] of main amplifier is that positive input terminal second input [5] is negative input end from the first input end [1] of steady zero type amplifier for positive input terminal second input [2] then for negative input end, when the first input end [4] of main amplifier is that negative input end second input [5] is positive input terminal from the first input end [1] of steady zero type amplifier for negative input end second input [2] then for positive input terminal, there is one to be used for steady zero the very little booster amplifier [A2] of drift, it just has, negative two inputs [7,8] and an output [9], the positive-negative input end [7 of booster amplifier [A2], 8], output [9] and from the one the second inputs [1 of steady zero type amplifier, 2], between the first input end [4] of main amplifier [A1] switch of containing [S1 is arranged respectively, S2, S3] second, the 3rd, the 4th loop, switch can be as analog switch, the switch of relay switch class, analog switch preferably, booster amplifier is to when steady zero type amplifier is surely zero, second, the 3rd, the switch in the 4th loop [S1～S3] is all connected, the output of booster amplifier [A2] changes the voltage on the main steady zero capacitance device [C1], make it to offset with the drift of input circuit, realization is to steady zero of steady certainly zero type amplifier, booster amplifier [A2] does not need when steady zero type amplifier is surely zero, the switch in the 4th loop [S3] disconnects, because the voltage maintenance effect of main steady zero capacitance device [C1], the one the second inputs [1 from steady zero type amplifier, 2] drift between will be very little still, above-mentioned two states can hocket, and also can have only first kind of state.

2, the linear amplifier of claim 1 defined, it is characterized in that: booster amplifier [A2] can be surely zero to self, it meets amplifier [A3] and the analog switch [S4 of an auxiliary capacitor [C2] before by a negative input end, S5, S6] form, one of auxiliary capacitor [C2] is terminated at the negative input end of amplifier [A3], the other end is as the negative input end [8] of booster amplifier [A2], the positive input terminal of amplifier [A3], output corresponds respectively to the positive input terminal [7] of booster amplifier [A2], output [9], between the positive input terminal of amplifier [A3] and a reference point [10] the 5th loop of being made up of analog switch [S4] is arranged, between end [8] that auxiliary capacitor [C2] does not link to each other with the negative input end of amplifier [A3] and above-mentioned reference point [10] the 6th loop of being made up of analog switch [S5] is arranged, the negative input end of amplifier [A3] and output have the 7th loop of being made up of analog switch [S6], described reference point [10] can be an earth terminal, it also can be the end [11] that main steady zero capacitance device [C1] does not link to each other with main amplifier [A1] first input end [4], at booster amplifier [A2] not to from steady zero type amplifier in steady zero time, booster amplifier [A2] can be surely zero to self, at this moment, the switch in second loop [S1], the switch of tertiary circuit [S2], the switch in the 4th loop [S3] all disconnects, the switch in the 5th loop [S4], the switch in the 6th loop [S5], the switch in the 7th loop [S6] is all connected, the drift of voltage on the auxiliary capacitor [C2] and amplifier [A3] is offset, to booster amplifier [A2] steady zero, to when steady zero type amplifier is surely zero, above-mentioned switch is logical at booster amplifier [A2], disconnected situation is opposite.

3, the linear amplifier of claim 2 defined, it is characterized in that: described first loop has a linear amplifier [A4] that is connected into the voltage follower form to be connected between the first input end [1] of leading steady zero capacitance device [C1] and oneself steady zero type amplifier, its positive input terminal links to each other with oneself first input end [1] of steady zero type amplifier, and an end [11] of negative input end, output and main steady zero capacitance device [C1] joins.