CN215342594U - Fully differential operational amplifier with high amplification factor - Google Patents

Abstract

The application relates to a high magnification's fully differential operational amplifier relates to amplifier circuit's field, and it includes P substrate, fixed connection in N trap on the P substrate, at least three fixed connection in P diffusion zone and fixed connection in the last control pole of N trap, the control pole is established to at least two, the quantity of P diffusion zone is more than the quantity of control pole, the control pole both sides all set up the P diffusion zone. The method has the effects of improving the amplification factor of the fully differential operational amplifier and enabling the circuit gain to approach infinity under certain conditions.

Description

Fully differential operational amplifier with high amplification factor

Technical Field

The present application relates to the field of amplification circuits, and in particular, to a fully differential operational amplifier.

Background

Since the introduction of modern technology, analog integrated circuit design has become an important part of people's daily life. The fully differential operational amplifier circuit is a circuit structure of differential input and differential output, because the currents of a P-type MOS tube and an N-type MOS tube can not be perfectly matched, the output common mode level is easy to deviate, because the common mode gain of a tail current source of an input differential pair is usually smaller, the output common mode point of the operational amplifier can not be controlled, the gain of a common mode feedback loop can be improved through a common mode feedback circuit so as to stabilize common mode signals, although the power consumption of the fully differential amplifier is increased compared with that of a single-ended output amplifier, the Common Mode Rejection Ratio (CMRR) and the output voltage swing amplitude are improved, and the fully differential operational amplifier circuit is more suitable for being applied to some high-precision applications.

However, the current fully differential operational amplifier still has a situation that the amplification factor does not meet the increasing demand, and the deficiency of the prior art needs to be overcome to improve the amplification factor of the fully differential operational amplifier.

SUMMERY OF THE UTILITY MODEL

In order to improve the amplification factor of the fully differential operational amplifier, the application provides a fully differential operational amplifier with high amplification factor.

The application provides a high-amplification-factor fully differential operational amplifier adopts the following technical scheme:

the utility model provides a high magnification's fully differential operational amplifier, includes P substrate, fixed connection in N trap on the P substrate, at least three fixed connection in P diffusion zone on the N trap and fixed connection in the control pole on the N trap, the control pole is established to at least two, the quantity of P diffusion zone is more than the quantity of control pole, the control pole both sides all set up the P diffusion zone.

Preferably, the number of the P diffusion regions and the control electrode is two, and SiO2 is fixedly arranged between the two P diffusion regions.

Preferably, the P substrate covers a side surface of the N well.

Preferably, the P substrate is fixedly provided with SiO2 at a position close to the side surface of the N well.

Preferably, the device comprises a metal connecting line A1 electrically connecting two P diffusion regions far away from each other in the first set, a metal connecting line A2 electrically connecting two P diffusion regions far away from each other in the second set, and a metal connecting line B electrically connecting the P diffusion regions at the intermediate positions in the first set and the second set, respectively, the metal connecting line A1 is further electrically connected to the control electrode far away from the SiO2 in the first set and the control electrode near the SiO2 in the second set, and the metal connecting line A2 is further electrically connected to the control electrode far away from the SiO2 in the second set and the control electrode near the SiO2 in the first set.

To sum up, the application comprises the following beneficial technical effects:

by arranging the fully differential operational amplifier, the amplification factor can be effectively increased, and the circuit gain can approach infinity under specific conditions.

Drawings

FIG. 1 is a schematic diagram of a high magnification fully differential operational amplifier according to the present application;

FIG. 2 is an equivalent circuit diagram of a high magnification fully differential operational amplifier of the present application;

FIG. 3 is a single-sided equivalent model of a high magnification fully differential operational amplifier of the present application;

fig. 4 is a schematic diagram of the structure of the amplifying circuit with high magnification in the present application.

Reference numerals: 1. a P substrate; 2. an N well; 201. a first P diffusion region; 202. a second P diffusion region; 203. a third P diffusion region; 204. a fourth P diffusion region; 205. a fifth P diffusion region; 206. a sixth P diffusion region; 207. a first control electrode; 208. a second control electrode; 209. a third control pole; 210. a fourth control electrode; 3. a first SiO 2; 4. a second SiO 2; 5. metal connection lines a 1; 6. metal connection lines a 2; 7. and a metal connecting wire B.

Detailed Description

The present application is described in further detail below with reference to figures 1-4.

The embodiment of the application discloses a fully differential operational amplifier with high amplification factor.

Example 1

Referring to fig. 1, the fully differential operational amplifier with high amplification factor includes a P substrate 1, and an N well 2 fixedly disposed in the P substrate 1, wherein a first P diffusion region 201, a second P diffusion region 202, a third P diffusion region 203, a fourth P diffusion region 204, a fifth P diffusion region 205, and a sixth P diffusion region 206 are sequentially and fixedly disposed in the N well 2, and a first control electrode 207, a second control electrode 208, a third control electrode 209, and a fourth control electrode 210 are further sequentially and fixedly disposed on the surface of the N well 2 away from the P substrate 1. The first control electrode 207 is located between the first P diffusion region 201 and the second P diffusion region 202, the second control electrode 208 is located between the second P diffusion region 202 and the third P diffusion region 203, the third control electrode 209 is located between the fourth P diffusion region 204 and the fifth P diffusion region 205, and the fourth control electrode 210 is located between the fifth P diffusion region 205 and the sixth P diffusion region 206.

Referring to fig. 1, the N-well 2 is recessed at a middle position and filled with a first SiO23, wherein the first SiO23 is located between the third P-diffusion region 203 and the fourth P-diffusion region 204. The P substrate 1 covers the side face of the N well 2, and the P substrate 1 is provided with a groove at a position close to the side face of the N well 2 and is filled with second SiO 24.

Referring to fig. 1, the first P diffusion region 201, the first control electrode 207, the third P diffusion region 203, and the third control electrode 209 are electrically connected with a metal connection line a 15, and a metal connection line a 15 is fixedly disposed; the second control pole 208, the fourth P diffusion region 204, the fourth control pole 210 and the sixth P diffusion region 206 are electrically connected with a metal connecting line a 26, and the metal connecting line a 26 is fixedly arranged; the second P diffusion region 202 and the fifth P diffusion region are electrically connected with a metal connection line B7, and the metal connection line B7 is fixedly disposed. The metal connection line a 15, the metal connection line a 26, and the metal connection line B7 may be made of aluminum or copper.

The present embodiment can be equivalent to the circuit shown in fig. 2, wherein the M1 and M2 transistors and the M1 'and M' transistors in the figure are equivalent MOS transistors included in the device of the present invention. The M1 tube and the M2 tube are load tubes connected by diodes, the two tubes have the same width-to-length ratio W/L, the transconductance of the two tubes is gm, and the equivalent impedance of the two tubes is 1/gm; wherein, the M1 ' tube and the M2 ' tube also have the same width-to-length ratio (W/L) ', and under the connection condition, the structure presents negative impedance characteristics, which is equivalent to that the transconductance of the two tubes is-gm ' and the equivalent impedance is-1/gm '.

Referring to fig. 3 and 4, an embodiment of the present application discloses a high amplification factor amplification circuit, and a gain of the circuit can be written as:

A=Gm*(Ro//Ro’)

=Gm*(1/(gm+(-gm’)))

=Gm/(gm-gm’)

wherein Gm is input tube transconductance.

And gm = u Cox (W/L)

gm’=u*Cox*(W/L)’

Let Δ gm = gm-gm'

△gm=u*Cox*(W/L-(W/L)’)

Therefore, if the values of W/L and (W/L) ' are reasonably taken, W/L- (W/L) ' is >0, and W/L- (W/L) ' approaches 0, the circuit gain A = Gm/. DELTA.gm can approach infinity, effectively ensuring ultrahigh amplification factor.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims (5)

1. A fully differential operational amplifier with high amplification, comprising: the device comprises a P substrate (1), an N trap (2) fixedly connected to the P substrate (1), at least three control electrodes fixedly connected to a P diffusion area on the N trap (2) and fixedly connected to the N trap (2), wherein the number of the control electrodes is at least two, the number of the P diffusion area is more than that of the control electrodes, and the P diffusion area is arranged on both sides of the control electrodes.

2. The fully differential operational amplifier with high amplification factor of claim 1, wherein: the number of the P diffusion regions and the number of the control electrodes are two, and SiO2 is fixedly arranged between the two P diffusion regions.

3. A fully differential operational amplifier with high amplification according to claim 1 or 2, wherein: the P substrate (1) covers the side face of the N trap (2).

4. A fully differential operational amplifier with high amplification according to claim 3, wherein: and SiO2 is fixedly arranged on the P substrate (1) close to the side surface of the N well (2).

5. The fully differential operational amplifier with high amplification factor of claim 2, wherein: including electrically connect two of keeping away from each other in the first set the metal connecting wire A1 (5) of P diffusion zone, electrically connect two of keeping away from each other in the second set the metal connecting wire A2 (6) of P diffusion zone and electrically connect first set and second set respectively and be located the intermediate position the metal connecting wire B (7) of P diffusion zone, keep away from in the first set still electric connection metal connecting wire A1 (5) SiO2 be close to in control pole and the second set SiO2 the control pole, keep away from in the second set still electric connection metal connecting wire A2 (6) control pole and the first set of SiO2 be close to SiO2 the control pole.

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