TW200941931A - Class AB operation amplifier circuit - Google Patents

Abstract

The class AB operation amplifiers are often used to amplify the power of the signal in the integrated circuit. However, it is not easy that the output current from the traditional class AB operation amplifier can achieve the limitations of the elements themselves. A class AB operation amplifier is provided. A voltage regulator is used to regulate the class AB operation amplifier. Thus, there can be the most swing range in the gates of the class AB operation amplifier. By this way, the class AB amplifier can provide the most output current as possible.

Description

200941931 IX. Description of the Invention: [Technical Field] The present invention relates to a class AB operational amplifier circuit, and more particularly to a class AB operational amplifier circuit with enhanced drive capability. [Prior Art] Class AB operational amplifiers play an important role in the design of integrated Q circuits. They are widely used in high-fidelity stereo equipment, microcomputers and others. Electronic equipment. The function of the class AB operational amplifier is to increase the output signal power to drive the load or the next stage of the circuit. FIG. 1 is a circuit diagram of a conventional class AB operational amplifier. Referring to FIG. 1, the conventional class AB operational amplifier 100 includes an input stage 11A, a bias circuit 120, and a complementary output stage 130, and a complementary output stage 13 is further connected to the load 140. The input stage 110 includes N-type field effect transistors I11-1 and U1~2, P-type field effect transistors 111-3 and 111-4, and current sources 141-1, 141_2. The bias circuit 12A includes P-type field effect transistors 121-1, 21 2 N field effect transistors 121-3, 131_4, and floating current sources 122-1, 122-2. The complementary output stage 13A includes a p-type field effect transistor and an N-type field effect transistor 131-2. In the input stage 110 of FIG. 1, the N-type field effect transistor lllq fish 111 -2 , p the criminal language from the band θ π * m, , ___

The output signal V 〇 , which is rotated by 130, forms a feedback circuit. 12b 2 each form a differential wheel: input signal Vi 'more receiving rounds 200941931090 26563twf.doc / p When the complementary output stage 130 needs to provide a large current to the load 140, the class AB operational amplifier 100 will utilize the bias voltage The bias point Va' in the path (10) is such that the source of the P(tetra) effect transistor 13:M has a large differential voltage with the gate stage, which in turn provides a larger current to the load 14 〇. When the complementary output stage 13〇 needs to draw back a large current from the load 140, the class AB operational amplifier 100 utilizes the bias point Vb in the bias circuit 120 to make the source of the field effect transistor 2 There is a large differential pressure with the gate, which in turn draws a large current from the load _ 。. Because the Va Vb is difficult to pull to full voltage, the p-type field effect transistor BM is difficult to reach the maximum output current that can be supplied to the load, and the N-type field effect transistor 131_2 is also difficult to reach its own. The maximum current that can be drawn back from the load 140, so the traditional AB class operational amplifier has limited driving capability. SUMMARY OF THE INVENTION An example of the present invention provides a ΑΒ-type operational amplifier circuit, which mainly uses a differential pressure regulator to regulate its complementary output stage so that its complementary output stage can output a large current to an external load. Or draw back a large current from the external load. An example of the present invention provides a ΑΒ-type operational amplifier circuit having a first end, a first end for receiving a first voltage, and a second end for outputting a second voltage, the 运算-type operational amplifier circuit including the first Differential wheel input, bias circuit and complementary output stage. The first differential input is lightly connected to the first and second ends, and has third and fourth ends. The bias circuit '2〇〇94l931m 26563twf.doc/p is programmed in the first differential input pair, and the white one is out of class, and the blessing is connected to the biasing circuit. The complementary N-type transistor, the first-type P-type and the first π-L are connected to the first P-type and the N-th type transistor, and the second Git is connected to the second Pit Determining a first disc at the third end and the complementary output stage. The second and fourth ends are respectively used to output the second circuit according to the magnitudes of the first and second voltages. The first differential current is used to receive the first and second currents, and the first differential pressure is generated according to the first and second currents. The invention adds a first differential pressure regulator to the bias circuit, and adjusts H at the f difference to generate a first difference 'this first pressure difference can adjust the output current magnitude of the complementary output stage' and the conventional AB type operation Compared with the amplifier, the class AB operational amplifier provided by the example of the present invention can output a larger current to its external load or withdraw a larger current from its external load. The above described features and advantages of the present invention will be more apparent from the following description of the appended claims. [Embodiment] FIG. 2A is a circuit diagram of a class AB operational amplifier 200A according to an embodiment of the present invention. Referring to FIG. 2A, the class AB operational amplifier 200A includes an input stage 110, a bias circuit 12A, and a complementary output stage 130. The input stage 110 includes N-type field effect transistors 111-1, 111-2 and a current source M1-1. The bias circuit 丨2〇 includes p-type field effect transistors 12M, 121-2, N-type field effect transistors ι21_3, 131_4, floating current sources 122-1, 122-2, and differential pressure regulators] 23-1 . Complementary output stage 130 includes a P-type field effect 200941931.090 26563t\vf.doc/p transistor 131-1 and an N-type field effect transistor 131-2. The differential pressure regulator 123-1 may be a resistance modulator. Referring to FIG. 2A, in the input stage 11A, the N-type field effect transistors 111-1, 111-2 constitute a differential input pair, and the gates of the N-type field effect transistors 111-1, 111-2 are respectively received. The input signal vi and the output signal v〇, the source of the n-type field effect transistors 111-1, 111-2 are coupled to the current source 141-1, and the other end of the current source 14M is grounded. The N-type field effect transistors 111_1 and π 1-2 have more output currents II and 12. ❹ In the bias circuit 120, the P-type field effect transistors ι21-1 and i21_2 form a P-type current mirror. The sources of the P-type field effect transistors 121-1 and 121-2 are all coupled to the power supply terminal VDD. The P-type field effect transistor and the gate of the 121_2 are connected to the drain of the P-type field effect transistor 121-1, and the drain of the p-type field effect transistor 121-1 is coupled to the floating current source 122-1. The input end is connected to the N-type field effect transistor 11]-1, and the end of the p-type field effect transistor 121_2 is coupled to one end of the resistance value modulator 123-1 (contact ^^" and the N-type field The drain of the effect transistor 111-2. The other end of the resistance modulator 123-1 (bias point G Va ) is lightly connected to the input terminal of the complementary output stage 130 and the floating current source 122-2. The field effect transistors 121-3 and 131-4 constitute an N-type current mirror, and the N-type field effect transistors 121-3 and 131-4 constitute the source of the N-type current mirror to be grounded, and the N-type field effect transistor 121_3 The drain of the N-type field effect transistor 12 core crystal 121_3 is further coupled to the output terminal of the floating current source 122-1, and the N-type field effect transistor m_4 is connected to the complement of the N-type field effect transistor m_4. Output stage 200941931 ... one by one, 090 26563twf.d〇c/p 130 and floating The output terminal (bias point Vb) of the current source 122_2. In the complementary output stage 130, the P-type field effect transistor 131-1 and the N-type field effect transistor 131-2 are connected in series to form a class AB amplifier. The P-type field effect transistor 131-1 is connected to the power supply terminal VDD, and the source of the N-type field effect transistor 111-2 is coupled to the ground. The P-type field effect transistor 13M and the ^^ field effect electricity day The body and the poles of the body 131-2 are connected to each other and output an output signal v. The complementary output stage is coupled to the external load 140, and one end of the load 14〇 receives the output port V〇, and the other end of the load 140 For grounding, the gate of the p-type field effect transistor 131-1 is drained to the bias point Va'. The gate of the N-type field effect transistor 131-2 is coupled to the bias point Vb. Class AB operational amplifier 20〇a The overall operation is as follows. The input stage 11 送 sends the currents n and 12 after receiving the input signal Vi and the output signal ν , and if the output signal Vo is smaller than the input signal Vi, the current 12 is smaller than the current II, and vice versa. The resistance modulator adjusts the magnitude of the resistance according to the current of n and 12, and the voltage of one end (bias point va) can control the P-type field in the complementary output stage 130. The current output of the effect transistor 13M. When the current 12 is less than the current II (ie, the output signal v〇 is smaller than the input signal, Vi), the resistance value of the resistance modulator becomes larger. Thus, the resistance variable 123- The voltage difference across the 1 also increases, so that the voltage value of the bias point can fall to a lower voltage value, ideally to the lowest voltage, so that the source of the P-type field effect crystal 131-1 The gate voltage difference can be maximized and the maximum current that can be quickly supplied to the load 140. In addition, the input stage 110 can also be coupled to the type of current mirror of the bias circuit 12A as shown in FIG. 2B. FIG. 2B is a circuit diagram of the class AB 200941931090 26563 twf.doc/p omni-amplifier 2 according to an embodiment of the invention. The class AB operational amplifier 2_ includes an input stage 110, a bias circuit 12A, a complementary output stage 13A, and a load 140. The 'input level UG includes p-type field effect transistor" η, (1) _4 2, the source 141 士 bias circuit 12G includes p-type field effect transistor 121 small _2, N-type field effect transistor (2) nick, The rotary current source 122 is small = 2 and the differential pressure regulator 123_2. Complementary output stage i3Q includes

The O body and the N type field effect transistor are fresh, and the differential pressure regulator 123-2 may be a resistance modulator. ^Continued ^Fig. 2Β 'In the input level U0, the p-type field effect transistor moving wheel is paired, the 场 field effect transistor (1)·3, 111·4 = other = input signal Vi and output signal ν〇, p type The field source power = m3, lu_4 source_ is connected to the current source (4)_2, and the current source (4)_2 2 is connected to the power supply terminal VDDOP type field effect transistors U1_3, 11M. In the bias circuit 120, the P-type field effect transistors 121-1 and 121_2, the ❹ 盥% crystals 1213 and 13M, and the floating current source (2)·1 \ are the same as those in FIG. 2A, and therefore will not be described again. The difference is in the second modulation, the position of 123·1 is shifted to the output of the floating current source 122_2=the resistance Hm23_2' is connected to the output terminal of the floating current source (bias point ¥13) P-type field effect transistor 121_4 (contact = 1). In addition, in the wheeled stage 11 wipes, the electric/spring 13 generated by the n-type field effect transistor (1) flows to the [si] field effect transistor 121_4, and the current 14 generated by the p-type field effect transistor UM flows to the N-type field. Effect transistor 121-3. In the complementary output stage 13Q, p-type field effect transistor and N-type field 200941931 090 265631νν Γ. d oc / p effect transistor 131-2 is functionally identical to Figure 2A, so it is not mentioned. The overall operation of the class AB operational amplifier 200B is as follows. The input stage 110 sends the current η, the work 2 after receiving the input signal Vi and the output signal v, and if the output signal Vo is greater than the input signal Vi, the current 14 is at the current 13. vice versa. Then, the resistance modulator adjusts the resistance according to the current of 13, 14, and the voltage of one end (bias point Vb) can control the current output of the complementary output stage 130. ❹ When the current 14 is less than the current 13 (i.e., the output signal Vo is greater than the input signal Vi), the resistance value of the resistance modulator 123_2 becomes larger. Therefore, the differential between the two ends of the resistance modulator I23-2 also increases, so that the bias voltage v ^ voltage value can rise to a higher voltage value, ideally can reach the most: difference = ^, N The source and inter-electrode _ of the field effect transistor _ from the (four) 3f take the large (four) differential pressure ' ^ type field effect transistor 131_2 to make the monthly b from the load 14 〇 to draw back the maximum current. The production grade 11G is more (four) _ to the p-type circuit of the tilting circuit 12G, and the mirror ' is as shown in Fig. 2c. Figure - is based on the two % two two two calculations, the power of the large equipment. When the signal is turned out, . 5 Tiger Vi%, resistance § Circumferential 123-1 electric power will be poor when the county will be the second sentence. As previously mentioned, this 140, while the maximum current is supplied from the s-transistor 131_1 to the load, so that the complementary ^!40 reflows to the N-type field effect transistor 131~2 is minimal, and when ιΓίι 3〇 is taken out to the load The current of 140 is the largest. When the inverse-electricity >1 difference is greater than the input signal Vi, the resistance modulator (2)-2 is left larger, and the voltage difference of the resistance modulator ^34 is minimum. 200941931 -' ·----- 090 26563twf.doc/p As mentioned above, 'the maximum current will be drawn back from the load 140 by the N-type field effect transistor 131-2, and the P-type field effect transistor 13M is minimized such that the complementary output stage 13〇 draws the maximum current from the load 140. In addition, the dust difference adjuster 123-1 may also be a transistor, as shown in Fig. 3. Fig. 3A is a circuit diagram of a class AB operational amplifier 3A according to another embodiment of the present invention. Wherein, the polarity of the transistor 123-1 is controlled by the control voltage vs and the control voltage VS1 can be a fixed value. The gate of the transistor 123" Q is coupled to the bias point Va for regulating the output current of the P-type field effect transistor 131-1 so that the P-type field effect transistor 131-1 can output its own maximum output. Current. The differential pressure regulator can also be used to regulate the output current of the N-type field effect transistor 13丨_2, as shown in Fig. 3B. Figure 3B is a circuit diagram of a class AB operational amplifier 300B in accordance with another embodiment of the present invention. The gate of the transistor 123_2 is controlled by the control voltage VS2, and the control voltage VS2 can be a constant value. The insufficiency of the transistor 123-1 is consumed by the bias point vb for regulating the output current of the n-type field effect transistor 131-2, so that the N-type field effect transistor 131_2 can be withdrawn from the load 140 by the maximum. Current. The differential pressure regulator can simultaneously regulate the output current of the P-type field effect transistor 131_1 and the N-type field effect transistor 31_2, as shown in FIG. 3C. Fig. 3C is a circuit diagram of a class AB operational amplifier 3〇〇c according to another embodiment of the present invention. When the output signal Vo is smaller than the input signal Vi, the voltage difference of the transistor 123-1 is the largest ' and the voltage difference between the source and the collector of the transistor Π3-2 is the smallest. As described above, at this time, the maximum current is supplied from the p-type field effect transistor 131_1 to the load 140, and the self-load 140 is reflowed to the N-type field effect power 12 200941931 26563 tw.d 〇 c / p crystal 131-2 is the minimum, The current output to the load 14 互补 of the complementary output stage 13 为 is maximized. On the contrary, when the output signal v 〇 is larger than the input signal vi, the voltage difference of the transistor 123-2 is the largest, and the voltage difference of the transistor is the smallest. As described above, at this time, the maximum output current will be drawn back from the load 140 by the N-type field effect transistor 131_2, and the minimum from the p-type field effect transistor 131-1, so that the complementary wheel-out stage 13 is self-loaded. The current drawn at 14 为 is the largest.

In addition, the P-type field effect transistor 123·1 and the field-effect transistor 123_2 of the class AB amplifiers 3〇〇A, 3〇〇B, and 3〇〇c in the above-described embodiments do not define an operation region, and may be Saturation mode or triode mode. . As described above, the present invention incorporates at least one differential voltage adjustment in the biasing circuit coupled between the input stage and the output stage. The input stage generates a current according to the input signal = "number", which can be used to regulate the differential pressure regulator, the output current of the output stage or the current drawn back. Compared with the conventional Ο 4 device, the embodiment of the present invention The provided class AB motion shovel can draw back or output a large current, and thus has a strong drive path. The present invention has been disclosed in the above embodiments by way of example - but it is not intended to limit the technical field of the present invention. Those who have the usual knowledge can make some changes and refinements without departing from the scope of this specification. Therefore, the definition of patent application scope is 13 200941931 090 26563twf. Doc/p [Simplified Schematic] Figure 1 is a circuit diagram of a conventional class AB operational amplifier 100. Figure 2A is a circuit diagram of a class AB operational amplifier 200A in accordance with an embodiment of the present invention. Figure 2B is an AB in accordance with an embodiment of the present invention. Figure 2C is a circuit diagram of a Class AB operational amplifier 2A in accordance with an embodiment of the present invention. Figure 3A is a circuit diagram of an ab-type operational amplifier 300A in accordance with another embodiment of the present invention. 3B is a circuit diagram of an ab class operational amplifier 300B according to another embodiment of the present invention. Fig. 3C is a circuit diagram of an ab class operational amplifier 300C according to another embodiment of the present invention. ** [Major component symbol description] 1〇〇: Conventional class AB operational amplifier 110: input stage 120: bias circuit 130: complementary wheel-out stage 14〇: load 111-1, 111, 2, 121_3, 121_4, 131_2: N-type field effect transistor t in-3 , 11M, 12M, 121_2, 13] U1: p-type field effect transistor 14 200941931_ 26563twf.doc/p 141-1, 141-2: current source 122-1, 122-2: floating current source 123-1 123-2: Differential pressure regulator Va, Vb: bias point

Val, Vbl: contact

Vo : output

Vi : Input VDD : Power terminal VS1, VS2 : Control voltage

15

Claims (1)

200941931_26563twf.doc/p X. Application Patent Range: 1. A class AB operational amplifier circuit having a first and a second end, the first end for receiving a first voltage, and the second end for outputting a The second voltage includes: a first differential input pair connected to the first and second ends, having a third end and a fourth end, configured to determine a first according to the magnitude of the first and second voltages And a second current, wherein the third and the fourth end respectively output the first and second currents; a bias circuit coupled to the first differential input pair, including a first a differential pressure regulator for receiving the first and second currents, and generating a first differential pressure according to the first and second currents to the first differential pressure regulator; and a complementary output stage coupled The first P-type and the first N-type transistor are connected in series with each other, and the second end is coupled between the first P-type and the first N-type transistor; wherein The first differential pressure regulator is coupled between the third end and the complementary output stage. A class AB operational amplifier circuit according to claim 1, wherein the first differential pressure regulator is a first resistance modulator for adjusting according to the first and second voltages. Change its resistance. 3. The class AB operational amplifier circuit of claim 2, wherein the first differential pressure regulator is coupled between the third terminal and the first P-type transistor. 4. A class AB operational amplifier circuit according to claim 3, wherein the first resistance modulator is a second P-type transistor, 16 200941931 090 26563twf.doc/p its gate handle Connected to a first fixed voltage. 5. The device of claim 2, wherein the first differential pressure regulator is between the first N-type transistors. In the seventh paragraph of the patent application, the type AB is considered to be the same as the second fixed voltage. 1冤日日体, 器电it range 3_述-footwork operation ^大^: ί2 differential input pair 'coupled to the first and second ends, with -= two = end, for Determining, according to the magnitude of the first and second voltages, wherein the fifth and the sixth ends are respectively used to rotate the first and second currents; then the circuit further comprises a second differential pressure adjuster, the partial Pressure == = two differential pressure regulator to record the third m = device mine [such as: r patent, around the seventh item - kind of class AB operation amplification ^ the second pressure difference adjustment ^ is the second resistance value The modulator, the first-resistance modulation ϋ is used to amplify the resistance of the resistor according to the first and second voltages, and the second-order resistor is a second Ρ Type transistor, /' > P constant voltage; the second resistance modulator is a 17th 200941931., 090 26563twf.doc / p two N-type transistor, the gate is coupled to a second 10. For example, the scope of the patent application =: the circuit of the device [...] when the one liter, the resistance of 4 = also rises. 4 '[Rise] the first-resistance modifier 12. As one of the 々 电路 电路 电路 , , , 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 When the time is lowered, the first differential pressure is 13. As in the patent circuit of the 12th item, the resistance of the second electric = operational amplifier rises.哗The first resistance value transformer circuit, 1; special! The above-mentioned kind of ab class operation put ^ 亥 亥 一 一 圭 圭 圭 圭 输入 输入 输入 圭 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻 轻The first end is not extremely gate-deficient at the second end, and the other end is connected to the ground and the other end is coupled to the source of the fourth germanium transistor.弟 - 士突i5·A type of 运算-like operation as described in item 5 of the patent application. :路: wherein the first differential input pair comprises: a first -1 type 黾 crystal, the gate of which is coupled to the first end, and the drain of the terminal 200941931 -090 26563 twf.doc/p is coupled to the third a fourth P-type transistor having a gate coupled to the second end and a drain coupled to the fourth end; and a current source coupled to the ground at one end and coupled to the other end Sources of the third and fourth N-type transistors. [16] A class AB operational amplifier circuit according to claim 1, wherein the bias circuit comprises: a ···H flow mirror ′ having a seventh and a human end, the seventh end The second end, the eighth end is connected to the fourth end; a second current mirror having a ninth and tenth end; and an ocean current source 'one of the floating current sources is lightly connected Between the eighth [ft end] another floating wire _ connected to the first differential pressure adjustment 19