CN101788835A - Band-gap reference source for realizing curvature correction through self-adaptive base current compensation - Google Patents

Abstract

Bandgap reference sources are widely used in various analog/digital-analog hybrid integrated circuits, and the temperature stability of the reference voltage source/current source determines the performance of the overall circuit. The equal (or proportional) collector current density of the triode is a basic condition for realizing the bandgap reference, but due to the essential properties of the triode flow control device, the shunting effect of the emitter-base current will affect the current density of the collector, thus Affects the temperature stability of the bandgap reference. Aiming at this problem, the present invention discloses a bandgap reference source that uses adaptive base current compensation technology to realize curvature correction, and ensures equal (or proportional) collector current densities of triodes through current compensation. The circuit in the invention is composed of a bandgap reference core circuit and two groups of self-adaptive base current compensation circuits.

Description

Adaptive Base Current Compensation Curvature Corrected Bandgap Reference Source

technical field

The invention belongs to the field of integrated circuit design and is used for generating reference voltages in analog/digital-analog hybrid integrated circuits. It specifically relates to a technique for adding compensation current to the emitter of the triode, thereby accurately stabilizing the current passing through the collector of the triode, and improving the temperature stability of the bandgap reference circuit.

Background technique

The current/voltage reference is the basis of various circuit behaviors, and the stability of the reference circuit, especially the stability to temperature, directly determines the performance of the overall circuit. Different devices present different response curves to temperature. Based on this principle, a temperature-independent reference source can be realized by using different devices to compensate each other.

Among the many ways to form a reference source, the bandgap reference is a relatively common structure. In the common CMOS/BiCMOS process, the junction potential of the PN junction is inversely proportional to the temperature [Equ.1], and the "emitter-base" voltage of the triode (Bipolar Junction Transistor, BJT) working at different current densities The difference ΔV _BE is proportional to the temperature [Equ.2], so using the junction voltage V _BE of the triode and the junction voltage difference ΔV _BE to complement each other is an effective method to achieve a temperature-independent reference voltage [Equ.3 ].

$\frac{<span\; class="notranslate">\; \&PartialD;</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}}}{<span\; class="notranslate">\; \&PartialD;</span>\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; q</span>}}{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Equivalent</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ]</span>$

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="V\; BE"\; filenames="HSA00000056274500011.png"\; state="\{\{state\}\}">V</figure-callout></span><figure-callout\; id="2"\; label="V\; BE"\; filenames="HSA00000056274500011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\frac{\mathrm{<span\; class="notranslate">\; no</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; kT</span>}}{\mathrm{<span\; class="notranslate">\; q</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Equivalent</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ]</span>$

V _REF ＝α ₁ V _BE +α ₂ ΔV _BE ＝α ₁ V _BE +α ₂ (V _T lnn) [Equ.3]

Figure 1 is a bandgap reference structure based on the basic form of the above method. Since the Q ₀ tube and Q ₁ tube have proportional emitter areas, and the equal-proportional current mirror is used as the load, they have proportional collector currents Density, so that the current through the resistor _R1 is a current proportional to the temperature (Proportional to Absolute Temperature, PTAT), which is temperature-compensated by the "emitter-base" voltage V _BE2 of _Q2 , in accordance with [Equ.3 ] in the form of expression, the formed V _REF is a temperature-independent reference voltage.

In fact, in the circuit of the bandgap reference in Figure 1, the collector currents of the transistors Q ₀ and Q ₁ are not completely equal. Accurate analysis shows that [Equ.2] can only be approximately established, and in Figure 2 A schematic diagram of the shunting effect of the base current of the triode on the emitter current is given, that is, the current density flowing through the triode Q ₀ and Q ₁ is not proportional. It is not difficult to see that, no matter for the triode Q ₀ with a small emitter area or the transistor Q ₁ with a large area, due to the existence of the "emitter-base" current, the formula [Equ.4] holds true exactly.

I _e =I _eb1 +I _c1 =I _eb2 +I _c2 [Equ.4]

On this basis, the following process can be obtained by deriving [Equ.2] again:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; BE</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="V\; BE"\; filenames="HSA00000056274500011.png"\; state="\{\{state\}\}">V</figure-callout></span><figure-callout\; id="2"\; label="V\; BE"\; filenames="HSA00000056274500011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; m</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; S</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Equivalent</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{\mathrm{<span\; class="notranslate">\; m</span>}{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}\mathrm{<span\; class="notranslate">\; ln</span>}\frac{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; eb</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; eb</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Equivalent</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; ]</span>$

It can be seen from the formula [Equ.6] that since the "emitter-base" current of the triode has a shunting effect on the collector current, and because there is no definite proportional relationship between I _eb1 and I _eb2 , in Figure 1 The collector currents of transistors _Q0 and _Q1 are not equal, resulting in the bandgap reference circuit in Figure 1 not satisfying the relation given by [Equ.2], thus fundamentally destroying the conditions for the establishment of the bandgap reference. Reflecting the characteristics of the specific circuit, it is shown that the temperature stability of the bandgap reference circuit in Figure 1 is poor.

Contents of the invention

Temperature performance is one of the most important performance indicators of the bandgap reference. As mentioned above, due to the existence of the "emitter-base" current of the triode, the bandgap reference of the basic structure in Figure 1 cannot provide a stable temperature-independent reference. .

In fact, the main reason for the poor temperature performance of the circuit is the properties of the triode current control device. The "emitter-base" current shunt effect affects the collector current of the triode, so the expression [Equ.2] introduces Uncertain items are removed, which is expressed in the schematic structure shown in Figure 2. Therefore, an effective method is to add a current compensation measure to eliminate the interference term in [Equ.6], and restore [Equ.6] to the form of [Equ.2], thereby ensuring the [Equ.3] temperature stability.

Based on this idea, the present invention proposes a novel high-stable bandgap reference structure based on the method of current compensation. The main technical points include the following two aspects:

1. Use the current compensation method to compensate the shunt effect of the base current of the triode and stabilize the collector current of the triode;

2. Adaptive base current pickup avoids the inherent disadvantage of low compensation accuracy in fixed current compensation.

The reference source disclosed in the present invention is based on these two considerations, and focuses on the technology of stabilizing the collector current of the triode. As shown in the circuit diagram in Figure 3, the emitters of the triode are respectively introduced with compensations equal to the respective base currents I _eb1 and I _eb2 Current, the circuit in Figure 4 is used to pick up the "emitter-base" current of the triode. The technical advantage of the present invention is:

1. The "emitter-base" current of the triode is picked up using an adaptive method, which is accurate in sampling and does not affect the working state of the triode in the core circuit;

2. Under the combined action of the load current mirror and the compensation current, the operating currents of the triodes in the core circuit of the bandgap reference are strictly equal to ensure the establishment of [Equ.3].

Description of drawings

The basic bandgap reference circuit structure of Fig. 1;

Fig. 2 is a schematic diagram of the shunting effect of the triode base current on the emitter current;

Figure 3 is a schematic diagram of the working state of the triode using current compensation;

Fig. 4 self-adaptive base current sampling circuit disclosed by the present invention;

Fig. 5 is the circuit structure of the bandgap reference source of the self-adaptive base current compensation curvature correction disclosed by the present invention;

Fig. 6 uses the actual output effect of the bandgap reference using the adaptive base current compensation curvature correction technology disclosed in the present invention;

FIG. 7 does not use the actual output effect of the bandgap reference using the adaptive base current compensation curvature correction technology disclosed in the present invention.

Detailed ways

The structure and working process of the bandgap reference source for curvature correction of adaptive base current compensation disclosed in the present invention will be described in detail below in conjunction with the accompanying drawings.

The bandgap reference source circuit of the adaptive base current compensation curvature correction disclosed by the present invention is composed of three parts, as shown in Figure 5, which are two sets of adaptive base current compensation circuits and the bandgap reference core circuit respectively, in the figure The starting circuit is not shown.

The structures of the two groups of adaptive base current compensation circuits are basically similar. The adaptive base current compensation circuit 1 consists of current mirrors MP ₄ /MP ₅ /MP ₆ , current mirrors MN ₀ /MN ₁ /MN ₂ /MN ₃ , and PMOS transistors Composed of MP ₃ and transistor Q ₃ , where Q ₃ has the same structure as Q ₁ , the source terminal of MP ₃ /MP ₄ /MP ₅ /MP ₆ is connected to the power supply, and the gate-drain of MP ₅ is shorted and connected to MP ₅ /MP ₆ and the drain of MN ₁ , the drain of MP ₃ is connected to the emitter of transistor _Q3 , the gate of MN ₁ /MN ₃ and the drain of MP ₅ , the base of transistor Q ₃ is connected to MN ₀ /MN The gate of ₂ and the drain of MN ₃ , the collector of Q ₃ is grounded, the gate of MP ₃ is connected to the output of the operational amplifier OP, the drain of MN ₀ is connected to the source of MN ₁ , and the drain of MN ₂ is connected to MN ₃ The source of MP ₆ is connected to the emitter of triode Q ₁ , and the source of MN ₀ /MN ₂ is grounded.

Adaptive base current compensation circuit 2 is composed of current mirror MP ₈ /MP ₉ /MP ₁₀ /MP ₁₁ , current mirror MN ₄ /MN ₅ /MN ₆ /MN ₇ , PMOS transistor MP ₇ and transistor Q ₄ , where Q ₄ has the same structure as Q ₀ /Q ₂ , the source of MP ₇ /MP ₈ /MP ₉ /MP ₁₀ /MP ₁₁ is connected to the power supply, the gate-drain of MP ₈ is shorted and connected to MP ₉ /MP ₁₀ /MP ₁₁ The gate terminal of MN ₅ and the drain terminal of MN 5, the drain terminal of MP ₇ is connected to the emitter of transistor Q ₄ , the gate of MN ₅ /MN ₇ and the drain of MP ₉ , and the gate of MP ₇ is connected to the output terminal of the operational amplifier OP , the base of transistor _Q4 is connected to the gate of _MN4 / _MN6 and the drain of _MN7 , the collector of _Q4 is connected to the ground, the drain of _MN4 is connected to the source of _MN5 , and the drain of _MN6 is connected to _MN7 The source of MN ₄ /MN ₆ is grounded, the drain of MP ₁₀ is connected to the emitter of transistor Q ₀ , and the drain of MP ₁₁ is connected to the emitter of transistor Q ₂ .

The core circuit of the bandgap reference is composed of triode Q ₀ /Q ₁ /Q ₂ , current mirror MP ₀ /MP ₁ /MP ₂ , operational amplifier OP and resistor R ₀ /R ₁ , in which the triode Q ₀ /Q ₂ has the same structure, And the emitter junction area is proportional to the emitter junction area of Q ₁ , the source terminal of MP ₀ /MP ₁ /MP ₂ is connected to the power supply, the gate terminal is connected to the output of the operational amplifier OP, and the base of the transistor Q ₀ /Q ₁ /Q ₂ and the collector are grounded, the drain of MP ₀ is connected to the emitter of Q ₀ and the inverting input of the operational amplifier OP, the drain of MP ₁ is connected to one end of the resistor R ₀ and the non-inverting input of the operational amplifier OP, and the resistor R ₀ The other end of the transistor is connected to the emitter of transistor Q ₁ , the drain of MP ₂ is connected to one end of resistor R ₁ , the other end of resistor R ₁ is connected to the emitter of Q ₂ , and the drain of MP ₂ is used as the output end of the reference voltage .

For the two sets of adaptive base current compensation circuits, the working process is basically the same. Taking the adaptive base current compensation circuit 2 as an example, since the MP ₇ /MP ₀ tubes have the same physical parameters and the gate-source connection method is the same, Make transistors _Q4 and _Q0 have the same DC load.

Therefore it can be seen that:

I _eb4 =I _eb0 [Equ.7]

Thus available:

I _MN7 ＝I _MN6 ＝I _MN5 ＝I _MN4 ＝I _eb4 [Equ.8]

I _MN5 ＝I _MP8 ＝I _MP9 ＝I _MP10 ＝I _MP11 [Equ.9]

It is not difficult to see from the transfer relationship of [Equ.7], [Equ.8] and [Equ.9] that the drain current of PMOS transistors MP ₁₀ and MP ₁₁ is the same as the base shunt of triode Q ₀ , that is:

I _eb0 ＝I _eb2 ＝I _MP10 ＝I _MP11 [Equ.10]

Therefore, injecting the drain current of MP ₁₀ into the emitter of Q ₀ can effectively compensate the base shunt I _eb0 of Q _0. By applying the Kirchhoff current equation to the triode, it can be seen that [Equ.11] is established, combined with [Equ.10], making [Equ.12] established.

I _e +I _MP10 ＝I _c0 +I _eb0 [Equ.11]

I _c0 ＝I _c2 ＝I _e [Equ.12]

Similarly, for the adaptive base current compensation circuit 1, the following expression can also be obtained:

I _eb3 ＝I _eb1 ＝I _MP6 [Equ.13]

I _c1 =I _e [Equ.14]

Based on the basis of [Equ.12] and [Equ.14], the triodes in the core circuit of the bandgap reference work at exactly the same collector current, which can strictly satisfy the conditions for the establishment of the formula [Equ.3] , thus improving the temperature stability of the reference voltage.

Fig. 6 and Fig. 7 are the comparison of the actual output effect of the bandgap reference circuit of the adaptive base current compensation curvature correction disclosed by the present invention, wherein Fig. 7 is the output effect of using the core circuit without base current compensation, at -40 Under the condition of ℃～125℃, as the temperature changes, the reference output changes by about 3.1mV, which is equivalent to the temperature stability index of 15.4ppm/℃; Figure 6 shows the reference output effect after base current compensation, in the same work Under normal conditions, as the temperature changes, the reference output only changes by about 1.27mV, which is equivalent to an increase in the temperature stability index to 6.2ppm/°C, while the power consumption only increases by about 40μW.

In summary, in view of the fact that the shunting effect of the "emitter-base" current will seriously affect the temperature stability of the bandgap reference, the present invention discloses a current compensation curvature correction technology, by applying a magnitude equal to The compensation current of the "emitter-base" current, combined with the function of the load current mirror, accurately stabilizes the current passing through the collector of the triode, thereby effectively improving the temperature stability of the bandgap reference circuit.

Claims (1)

1. A circuit structure, comprising: The triodes in the core circuit of the bandgap reference have the same (or proportional) current density, which is the basic element for stable reference output. Using adaptive current compensation technology, it avoids the influence of the "emitter-base" current shunt effect of the triode, It can effectively improve the temperature stability of the bandgap reference circuit; the specific circuit form includes three components: the core circuit of the bandgap reference, the adaptive base current compensation circuit (1) and the adaptive base current compensation circuit (2). The gap reference core circuit is composed of current mirror (MP ₀ /MP ₁ /MP ₂ ), operational amplifier (OP), triode (Q ₀ /Q ₁ /Q ₂ ) and resistor (R ₀ /R ₁ ), among which the triode (Q ₀ /Q ₂ ) have the same structure, and the emitter junction area is proportional to the emitter junction area of the triode (Q ₁ ), the source terminal of the PMOS transistor (MP ₀ /MP ₁ /MP ₂ ) is connected to the power supply, and the gate terminal is connected to the operational amplifier (OP) output, the base and collector of the transistor (Q ₀ /Q ₁ /Q ₂ ) are grounded, and the drain of the PMOS transistor (MP ₀ ) is connected to the emitter of the transistor (Q ₀ ) and the operational amplifier (OP) The inverting input terminal of the PMOS transistor (MP ₁ ) is connected to one end of the resistor (R ₀ ) and the non-inverting input terminal of the operational amplifier (OP), and the other end of the resistor (R ₀ ) is connected to the triode (Q ₁ ) The emitter, the drain of the PMOS tube (MP ₂ ) is connected to one end of the resistor (R ₁ ), and serves as the output port of the reference voltage, and the other end of the resistor (R ₁ ) is connected to the emitter of the triode (Q ₂ ); Adaptive base current compensation circuit (1), consisting of PMOS tube current mirror (MP ₄ /MP ₅ /MP ₆ ), NMOS tube current mirror (MN ₀ /MN ₁ /MN ₂ /MN ₃ ), PMOS tube (MP ₃ ) and triode (Q ₃ ), wherein the triode (Q ₃ ) has the same structure as (Q ₁ ), the source terminal of the PMOS transistor (MP ₃ /MP ₄ /MP ₅ /MP ₆ ) is connected to the power supply, and the PMOS transistor (MP ₄ ) is short-circuited to the drain of the PMOS transistor (MP ₅ /MP ₆ ) and the drain of the NMOS transistor (MN ₁ ), and the drain of the PMOS transistor (MP ₃ ) is connected to the emitter of the triode (Q ₃ ). , the gate of the NMOS transistor (MN ₁ /MN ₃ ) and the drain of the PMOS transistor (MP ₅ ), the gate of the PMOS transistor (MP ₃ ) is connected to the output of the operational amplifier (OP), and the base of the triode (Q ₃ ) Connect the gate of the NMOS transistor (MN ₀ /MN ₂ ) to the drain of the NMOS transistor (MN ₃ ), the collector of the triode (Q ₃ ) is grounded, and the drain of the NMOS transistor (MN ₀ ) is connected to the NMOS transistor (MN ₁ ) The source of the NMOS transistor (MN ₂ ) is connected to the drain of the NMOS transistor (MN 2 ₃ ), the source of the PMOS transistor (MP ₆ ) is connected to the emitter of the triode (Q ₁ ), and the source of the NMOS transistor (MN ₀ /MN ₂ ) is grounded; the adaptive base current compensation circuit (2), Composed of PMOS tube current mirror (MP ₈ /MP ₉ /MP ₁₀ /MP ₁₁ ), NMOS tube current mirror (MN ₄ /MN ₅ /MN ₆ /MN ₇ ), PMOS tube (MP ₇ ) and triode (Q ₄ ) , where the triode (Q ₄ ) has the same structure as (Q ₀ /Q ₂ ), the source of the PMOS tube (MP ₇ /MP ₈ /MP ₉ /MP ₁₀ /MP ₁₁ ) is connected to the power supply, and the PMOS tube (MP ₈ ) The gate-drain of the PMOS transistor (MP ₉ /MP 10 /MP 11 ) is shorted and connected to the gate terminal of the PMOS transistor (MP 9 /MP ₁₀ /MP ₁₁ ) and the drain terminal of the NMOS transistor (MN ₅ ), and the drain terminal of the PMOS transistor (MP ₇ ) is connected to the transistor (Q ₄ ) The emitter, the gate of the NMOS transistor (MN ₅ /MN ₇ ) and the drain of the PMOS transistor (MP ₉ ), the gate of the PMOS transistor (MP ₇ ) is connected to the output terminal of the operational amplifier (OP), and the triode (Q ₄ ) The base of the NMOS transistor (MN ₄ /MN ₆ ) is connected to the gate of the NMOS transistor (MN 4 /MN 6 ) and the drain of the NMOS transistor (MN ₇ ), the collector of the triode (Q ₄ ) is grounded, and the drain of the NMOS transistor (MN ₄ ) is connected to the NMOS transistor ( MN ₅ ), the drain of the NMOS transistor (MN ₆ ) is connected to the source of the NMOS transistor (MN ₇ ), the source of the NMOS transistor (MN ₄ /MN ₆ ) is grounded, and the drain of the PMOS transistor (MP ₁₀ ) connected to the emitter of the triode (Q ₀ ), and the drain of the PMOS transistor (MP ₁₁ ) connected to the emitter of the triode (Q ₂ ), wherein all the PMOS transistors have the same width and length.

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