A low dropout wideband linear voltage regulator with low voltage input-output characteristics

Abstract

The application discloses a low-dropout wideband linear voltage regulator with low voltage input and output characteristics, and belongs to the field of power management integrated circuits. A voltage signal obtained by dividing the output of the linear voltage regulator is compared and amplified with a reference voltage by using a double differential amplifier, and a push-pull amplifier processes the signal amplified by the double differential amplifier to control the base driving current of a power transistor, thereby realizing low-voltage wideband voltage regulation output. The application does not use an on-chip capacitor for voltage regulation loop frequency compensation, but uses a double differential amplifier, a push-pull amplifier, a power transistor and a voltage dividing resistor to form a high-speed voltage regulation loop. The base series resistor of the power transistor realizes power transistor array current balance on one hand, and generates a zero point on the other hand, which offsets the sub-pole generated by the large parasitic capacitance of the power transistor base. An output capacitor uses a ceramic capacitor to generate an output pole, which is used as a loop compensation capacitor to realize voltage regulation loop compensation, and significantly enhances the load transient response capability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power management integrated circuits, and relates to a low-dropout wideband linear voltage regulator with low-voltage input and output characteristics. BACKGROUND

[0002] With the continuous development of semiconductor process technology, the process integration is higher and higher, and the performance and function of linear power supply are constantly improved. The linear power supply has the characteristics of low ripple, low noise and simple application, and has been widely used in various electronic systems, such as medical equipment, portable electronic products, automobile electronics, civil aviation and aerospace, and accounts for about 20% of the power management market share, supporting the rapid development of electronic technology industry.

[0003] With the continuous increase of the integration of electronic systems and the rapid development of advanced process technology, the process feature size used by system chips and data link chips is smaller and smaller, the working frequency is continuously increased, and the working voltage shows a downward trend. Therefore, a low-voltage output high-speed low-dropout linear voltage regulator is urgently needed, and the output current is large. The output voltage of the current domestic large-current linear voltage regulator mainstream product is greater than or equal to 1.5V. The low-dropout linear voltage regulator adopts LPNP or PMOS as a power transfer device. However, the output impedance of the device is very large, and changes greatly in the normal application output current range, which leads to the increasing difficulty of the design of the system loop frequency compensation and stability of the high-speed linear voltage regulator, the very complex circuit structure, the large chip area of the loop control circuit, and the difficult control of the chip cost. The output capacitor of the voltage regulation loop needs to use a tantalum capacitor to introduce a zero point by using the parasitic resistance to realize loop frequency compensation. On the one hand, the tantalum capacitor has a large cost and occupies a large PCB area. On the other hand, the zero point is greatly related to the type of the capacitor, and the parasitic resistance of tantalum capacitors of different values and different manufacturers has great differences. Therefore, the actual application cost and stability are difficult to control when the tantalum capacitor is used as the output capacitor. SUMMARY

[0004] The application aims to solve the problem of the large output impedance of the circuit structure in the prior art, the great change in the normal application output current range, and the poor stability of the voltage regulation loop, and provides a low-dropout wideband linear voltage regulator with low-voltage input and output characteristics.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0006] The low-dropout wideband linear voltage regulator with low-voltage input and output characteristics provided by the application comprises a double-differential amplifier, a push-pull amplifier, a power transistor base series resistor, a fast access resistor and a power transistor.

[0007] The positive input of the dual error amplifier is connected to a reference voltage, and the negative input is connected to the voltage signal obtained by dividing the output voltage of the voltage regulator. The two outputs are connected to the two inputs of a push-pull amplifier, respectively. The output of the push-pull amplifier is connected to one end of the series resistor between the base and the power transistor, and the other end of the series resistor is connected to the base of the power transistor. One end of the fast-path resistor is connected to one end of the series resistor between the base and the power transistor, and the other end of the fast-path resistor is connected to V. OUT The input voltage of the node, dual error amplifier, and push-pull amplifier is V. CNTL The collector of the power transistor is connected to V. IN At the node, the base of the power transistor is connected to a series resistor, and the emitter of the power transistor is connected to V. OUT node.

[0008] Preferably, the input power supply voltage V of the dual differential amplifier and push-pull amplifier circuit is... CNTL With the input power supply voltage V of the power transistor IN The following conditions must be met: V CNTL -V IN ≥1V.

[0009] Preferably, a bias circuit is connected to the dual differential amplifier, and the bias circuit includes a transistor Q. lp6 transistor Q n9 and the first resistor r p1 transistor Q lp6 Emitter connected to V CNTL transistor Q lp6 Both the base and collector of transistor Q are connected to node a2; n9 The base of the transistor is connected to node a26, and the transistor Q is connected to node a26. n9 The collector node a2 of the transistor Q n9 The emitter is connected to node a1; the first resistor r p1 One end is connected to node a1, and the other end is connected to node GND.

[0010] Preferably, the dual differential amplifier includes an emitter follower amplifier, a first differential amplifier, and a second differential amplifier.

[0011] Preferably, the emitter follower amplifier includes a transistor Q. sp1 transistor Q lp8 transistor Q sp2 and transistor Q lp7 ;

[0012] transistor Q sp1 The base is connected to node a16, the collector to node GND, and the emitter to node a3; Q lp8 The base of the transistor is connected to node a2, the collector is connected to node a3, and the emitter is connected to V. CNTL Transistor Q sp2The base is connected to node SENSE, the collector to node GND, and the emitter to node a8; transistor Q lp7 The base is connected to node a2, the collector to node a8, and the emitter to node V. CNTL .

[0013] Preferably, the first differential amplifier includes transistor Q. lp11 transistor Q n12 transistor Q lp12 transistor Q n13 transistor Q n7 Fifth resistor r p5 Second resistor r p2 and the third resistor r p3 ;

[0014] transistor Q lp11 The base is connected to node a3, the collector to node a4, and the emitter to node a10; transistor Q n12 The base is connected to node a4, the collector is connected to node a4, and the emitter is connected to node GND; transistor Q lp12 The base is connected to node a8, the collector to node a7, and the emitter to node a11; transistor Q n13 The base is connected to node a4, the collector to node a7, and the emitter to node GND; transistor Q n7 The base is connected to node a7, the collector is connected to node a7, and the emitter is connected to node a12; the fifth resistor r p5 One end is connected to node a12, and the other end is connected to node GND; the second resistor r p2 One end is connected to node a9, and the other end is connected to node a10; the third resistor r p3 One end is connected to node a9, and the other end is connected to node a11.

[0015] Preferably, the second differential amplifier includes transistor Q. lp10 transistor Q n10 transistor Q lp9 transistor Q n11 transistor Q n8 Fourth resistor r p4 Second resistor r p2 and the third resistor r p3 ;

[0016] transistor Q lp10 The base is connected to node a8, the collector to node a6, and the emitter to node a11; transistor Q n10 The base is connected to node a6, the collector is connected to node a6, and the emitter is connected to node GND; transistor Q lp9 The base is connected to node a3, the collector to node a5, and the emitter to node a10; transistor Q n11The base is connected to node a6, the collector to node a5, and the emitter to node GND; transistor Q n8 The base is connected to node a5, the collector to node a5, and the emitter to node a13; the fourth resistor r p4 One end is connected to node a13, and the other end is connected to node GND.

[0017] Preferably, the push-pull amplifier circuit includes transistor Q. n6 transistor Q n4 transistor Q lp3 transistor Q lp4 and transistor Q n5 ;

[0018] transistor Q n6 The base is connected to node a7, the collector is connected to node a7, and the emitter is connected to node GND; transistor Q n4 The base is connected to node a3, the collector to node a14, and the emitter to node a17; transistor Q lp3 Base terminal a14, collector terminal a14, emitter terminal V CNTL Transistor Q lp4 The base is connected to node a14, the collector to node a15, and the emitter to node V. CNTL Transistor Q n5 The base is connected to node a5, the collector to node a15, and the emitter to node GND.

[0019] Preferably, the current of the output power transistor is small when the linear regulator is under no-load or light-load conditions.

[0020] Preferably, when the linear regulator is under full load or heavy load, the current of the output power transistor is large.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention proposes a low-dropout broadband linear regulator with low-voltage input-output characteristics. It employs a dual differential amplifier to monitor the regulator's output voltage. After amplification by comparing the output voltage with a reference voltage, the output current and voltage of a push-pull amplifier are controlled, thereby controlling the output voltage of the broadband regulator and achieving high-current regulated output. The push-pull amplifier dynamically adjusts its output current based on the magnitude of the regulator's output current, and the secondary pole generated by the base of the power transistor automatically adjusts according to changes in the output pole. A dual-power supply is used, leveraging the low output impedance of the power transistor to design a high-speed voltage regulation loop. A simple compensation method is employed, and the output capacitor is a resistor, meeting the stability requirements of the voltage regulation loop. Therefore, the linear regulator proposed in this invention not only achieves good voltage regulation loop stability but also enables the commercialization of low-dropout, broadband, high-current linear regulators, adapting to the ever-evolving needs of electronic systems.

[0023] Furthermore, the input power supply voltage V of the dual differential amplifier and push-pull amplifier circuit... CNTL With the input power supply voltage V of the power transistor IN Certain conditions must be met in order to achieve low input-output voltage drop characteristics. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a structural diagram of the low-voltage broadband linear regulator of the present invention.

[0026] Figure 2 This is a transistor-level circuit diagram of the low-voltage broadband linear regulator of the present invention.

[0027] Figure 3 This is a typical application circuit diagram of the low-voltage broadband linear regulator of the present invention.

[0028] Among them, 1000-dual differential amplifier, 2000-push-pull amplifier, 3000-NPN power transistor base series resistor, 6000-fast path resistor, and 5000-NPN power transistor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] To meet the needs of modern electronic power supply systems for high-current, low-dropout, high-speed linear regulators, without consuming additional electrostatic current, achieving better voltage regulation loop stability, and avoiding the dependence of conventional high-current, low-dropout linear regulators on the equivalent series resistance of off-chip output filter capacitors, as well as the drawback of requiring large-area on-chip compensation capacitors, this invention proposes a low-dropout broadband linear regulator with low-voltage input-output characteristics, such as... Figure 1 As shown, the system includes a dual differential amplifier 1000, a push-pull amplifier 2000, an NPN power transistor base series resistor 3000, a fast-path resistor 6000, and an NPN power transistor 5000. The positive input of the dual differential amplifier 1000 is connected to a 0.8V reference voltage, and the negative input is connected to the voltage signal node 1 (after voltage division from the regulator output voltage). Its two output terminals are connected to the two input terminals of the push-pull amplifier 2000, i.e., nodes 2 and 3, respectively. The output terminal of the push-pull amplifier 2000 is connected to one end of the power transistor base series resistor R3 3000 at node 4. The other end of the power transistor base series resistor R3 3000 at node 5 is connected to the base of the NPN power transistor 5000. One end of the fast-path resistor 6000 is connected to node 4, and the other end is connected to V... OUT Node; The input voltage of the dual differential amplifier 1000 and the push-pull amplifier 2000 is V. CNTL The collector of the NPN power transistor 5000 is connected to V. IN Node, base connected to node 5, emitter connected to V OUT Node. Input power supply voltage V for the dual differential amplifier 1000 and the push-pull amplifier circuit 2000. CNTL The input power supply voltage V of the power transistor 5000 IN Condition V is satisfied CNTL -V IN ≥1V, in order to achieve low input-output voltage drop characteristics.

[0037] 1000 dual differential amplifier Figure 2 As shown, the main function is to compare and amplify the output voltage of the sampling regulator with a 0.8V reference voltage to drive the input port of the push-pull amplifier. A bias circuit is connected to the dual differential amplifier to provide static bias current for the dual differential circuit. The bias circuit includes transistor Q. lp6 transistor Q n9 and the first resistor r p1 transistor Q lp6 Emitter connected to V CNTL transistor Q lp6 Both the base and collector of transistor Q are connected to node a2; n9 The base of the transistor is connected to node a26, and the transistor Q is connected to node a26. n9 The collector node a2 of the transistor Q n9 The emitter is connected to node a1; the first resistor r p1One end is connected to node a1, and the other end is connected to node GND.

[0038] The dual differential amplifier 1000 includes an emitter follower amplifier, a first differential amplifier, and a second differential amplifier.

[0039] The emitter follower amplifier, serving as the input stage of the dual differential amplifier, includes transistor Q. sp1 transistor Q lp8 transistor Q sp2 and transistor Q lp7 Transistor Q sp1 The base is connected to node a16, the collector to node GND, and the emitter to node a3; Q lp8 The base of the transistor is connected to node a2, the collector is connected to node a3, and the emitter is connected to V. CNTL Transistor Q sp2 The base is connected to node SENSE, the collector to node GND, and the emitter to node a8; transistor Q lp7 The base is connected to node a2, the collector to node a8, and the emitter to node V. CNTL .

[0040] The first differential amplifier drives the push-pull amplifier, which outputs the pull-down transistor Q. n6 Including transistor Q lp11 transistor Q n12 transistor Q lp12 transistor Q n13 transistor Q n7 and the fifth resistor r p5 Transistor Q lp11 The base is connected to node a3, the collector to node a4, and the emitter to node a10; transistor Q n12 The base is connected to node a4, the collector is connected to node a4, and the emitter is connected to node GND; transistor Q lp12 The base is connected to node a8, the collector to node a7, and the emitter to node a11; transistor Q n13 The base is connected to node a4, the collector to node a7, and the emitter to node GND; transistor Q n7 The base is connected to node a7, the collector is connected to node a7, and the emitter is connected to node a12; the fifth resistor r p5 One end is connected to node a12, and the other end is connected to node GND; the second resistor r p2 One end is connected to node a9, and the other end is connected to node a10; the third resistor r p3 One end is connected to node a9, and the other end is connected to node a11.

[0041] The second differential amplifier drives the push-pull amplifier output pull-down transistor Q. n5 Including transistor Q lp10 transistor Qn10 transistor Q lp9 transistor Q n11 transistor Q n8 and the fourth resistor r p4 Transistor Q lp10 The base is connected to node a8, the collector to node a6, and the emitter to node a11; transistor Q n10 The base is connected to node a6, the collector is connected to node a6, and the emitter is connected to node GND; transistor Q lp9 The base is connected to node a3, the collector to node a5, and the emitter to node a10; transistor Q n11 The base is connected to node a6, the collector to node a5, and the emitter to node GND; transistor Q n8 The base is connected to node a5, the collector to node a5, and the emitter to node a13; the fourth resistor r p4 One end is connected to node a13, and the other end is connected to node GND.

[0042] Push-pull amplifier 2000 Figure 2 As shown, the main function is to convert the differential signal output from the dual differential amplifier into a current signal, providing drive current for the output power circuit. The push-pull amplifier circuit includes transistor Q. n6 transistor Q n4 transistor Q lp3 transistor Q lp4 and transistor Q n5 Transistor Q n6 The base is connected to node a7, the collector is connected to node a7, and the emitter is connected to node GND; transistor Q n4 The base is connected to node a3, the collector to node a14, and the emitter to node a17; transistor Q lp3 Base terminal a14, collector terminal a14, emitter terminal V CNTL Transistor Q lp4 The base is connected to node a14, the collector to node a15, and the emitter to node V. CNTL Transistor Q n5 The base is connected to node a5, the collector to node a15, and the emitter to node GND.

[0043] The following is a specific application implementation of this linear regulator:

[0044] This linear regulator is designed and implemented using a bipolar process. The control circuit receives power supply V. CNTL The voltage is 3V to 16V, and the NPN power transistor input power supply V INWith a voltage range of 1.25V to 16V, an output current range of 0.8 to 3A, and an output voltage range of 0.8V to 15V, it features low-voltage output and fast load transient response, and can be widely used in power supply for large-scale digital circuits and systems such as CPUs, DSPs, MCUs, and memory.

[0045] According to the invention, a typical application diagram of the circuit is shown below. Figure 3 As shown, where C IN1 =0.1μF, C IN2 =1μF, C IN3 =0.1μF, C IN4 =10μF, C OUT =47μF ceramic capacitor, ESR less than 50m, R L1 This is the load for the linear regulator. Assuming the electrical connection characteristics of the linear regulator are correct, it is configured... Figure 3 By varying the ratios of R1 and R2, an output voltage of 0.8V to 15V and an output current range of 0 to 3A can be achieved.

[0046] Experimental results show that a 3A low-voltage broadband linear regulator designed based on this invention has a control circuit input power supply V CNTL The voltage is 3V to 16V, and the NPN power transistor input power supply V IN With a voltage range of 1.25V to 16V, an output current range of 0.8 to 3A, and an output voltage range of 0.8V to 15V, it can be widely used for power supply of large-scale digital circuits and systems such as CPUs, DSPs, MCUs, and memory.

[0047] This invention proposes a low-dropout broadband linear regulator with low-voltage input-output characteristics. The positive input of a dual differential amplifier is connected to a 0.8V reference voltage, and the negative input is connected to the regulator's output voltage signal after being divided by a resistor. The input of a push-pull buffer amplifier is connected to the two outputs of the differential amplifier. The power transistor is composed of many NPN transistor cells, with a resistor connected in series at the base of each transistor. The input stage of this power module is connected to the output of the push-pull amplifier, and the emitter of the power NPN transistor is the output port of the regulator.

[0048] This system employs an NPN power transistor as the output regulation device, with dual power inputs to achieve low dropout voltage. A high-speed voltage regulation loop is formed using a dual differential amplifier, a push-pull amplifier, the NPN transistor, and voltage divider resistors (output voltage adjustable, external resistors R1 and R2). The series resistor at the base of the NPN power transistor balances the current in the power element array and generates a zero point to offset the secondary pole caused by the large parasitic capacitance at the base of the NPN power transistor. The output capacitor is a ceramic capacitor (series equivalent resistance less than 50mΩ), generating an output pole and serving as a loop compensation capacitor to achieve voltage regulation loop compensation. The very small series equivalent resistance significantly enhances the transient response capability. This voltage regulation structure reduces chip and application costs and offers advantages such as high current, low dropout voltage, and high speed.

[0049] Specifically, a dual differential amplifier is used to monitor the output voltage of the voltage regulator. After comparing and amplifying the output voltage with the reference voltage, the output current and voltage of the push-pull amplifier are controlled, thereby controlling the output voltage of the broadband voltage regulator and realizing the function of high current voltage regulation output. The push-pull buffer amplifier dynamically adjusts its output current based on the magnitude of the regulator's output current. The secondary pole generated by the base of the NPN power transistor automatically adjusts according to the change in the output pole. When the linear regulator is operating under no-load or light-load conditions, the drive current required by the NPN power transistor base is very small, the BE junction voltage of the NPN transistor in the output stage of the push-pull buffer amplifier is relatively large, and the output drive current of the NPN power transistor is small. When the linear regulator is operating under full-load or heavy-load conditions, the drive current required by the NPN power transistor base is relatively large, the BE junction voltage of the NPN transistor in the output stage of the push-pull buffer amplifier is relatively small, and the output drive current of the NPN power transistor is relatively large. From no-load to full-load, the push-pull amplifier automatically adjusts its output impedance to achieve adaptive adjustment of the secondary pole. A zero point is introduced by the series resistor at the base of the NPN power transistor to cancel the dynamic secondary pole and complete loop frequency compensation, achieving a stable output voltage of 3A broadband regulator within the load current range of 0A to 3A. The input voltage of the control circuit and the input voltage of the NPN power transistor are V. CNTL and V IN V CNTL The range is 3V to 18V, V IN With a voltage range of 1.25V to 18V, this voltage regulation loop structure utilizes an NPN power transistor with wide bandwidth characteristics to achieve wide bandwidth and low dropout voltage performance.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-dropout broadband linear regulator with low-voltage input-output characteristics, characterized in that, This includes dual differential amplifiers, push-pull amplifiers, power transistor base series resistors, fast-path resistors, and power transistors; The positive input of the dual differential amplifier is connected to a reference voltage, and the negative input is connected to the voltage signal obtained by dividing the output voltage of the voltage regulator. The two outputs are connected to the two inputs of a push-pull amplifier, respectively. The output of the push-pull amplifier is connected to one end of the series resistor between the base and the power transistor, and the other end of the series resistor is connected to the base of the power transistor. One end of the fast-path resistor is connected to one end of the series resistor between the base and the power transistor, and the other end of the fast-path resistor is connected to V. OUT The input voltage of the node, the dual differential amplifier, and the push-pull amplifier is V. CNTL The collector of the power transistor is connected to V. IN At the node, the base of the power transistor is connected to a series resistor, and the emitter of the power transistor is connected to V. OUT node; A dual differential amplifier includes an emitter follower amplifier, a first differential amplifier, and a second differential amplifier; the emitter follower amplifier includes a transistor Q. sp1 transistor Q lp8 transistor Q sp2 and transistor Q lp7 Transistor Q sp1 The base is connected to node a16, the collector to node GND, and the emitter to node a3; Q lp8 The base of the transistor is connected to node a2, the collector is connected to node a3, and the emitter is connected to V. CNTL Transistor Q sp2 The base is connected to node SENSE, the collector to node GND, and the emitter to node a8; transistor Q lp7 The base is connected to node a2, the collector to node a8, and the emitter to node V. CNTL ; The push-pull amplifier includes transistor Q. n6 transistor Q n4 transistor Q lp3 transistor Q lp4 and transistor Q n5 Transistor Q n6 The base is connected to node a7, the collector to node a17, and the emitter to node GND; transistor Q n4 The base is connected to node a3, the collector to node a14, and the emitter to node a17; transistor Q lp3 Base terminal a14, collector terminal a14, emitter terminal V CNTL Transistor Q lp4 The base is connected to node a14, the collector to node a15, and the emitter to node V. CNTL Transistor Q n5 The base is connected to node a5, the collector is connected to node a15, and the emitter is connected to node GND. The output of the first differential amplifier is at node a7, and the output of the second differential amplifier is at node a5.

2. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 1, characterized in that, Input power supply voltage V of dual differential amplifier and push-pull amplifier CNTL With the input power supply voltage V of the power transistor IN The following conditions must be met: V CNTL -V IN ≥1V.

3. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 1, characterized in that, The dual differential amplifier is connected to a bias circuit, which includes transistor Q. lp6 transistor Q n9 and the first resistor r p1 transistor Q lp6 Emitter connected to V CNTL transistor Q lp6 Both the base and collector of transistor Q are connected to node a2; n9 The base of the transistor is connected to node a26, and the transistor Q is connected to node a26. n9 The collector node a2 of the transistor Q n9 The emitter is connected to node a1; the first resistor r p1 One end is connected to node a1, and the other end is connected to node GND.

4. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 1, characterized in that, The first differential amplifier includes transistor Q. lp11 transistor Q n12 transistor Q lp12 transistor Q n13 transistor Q n7 Fifth resistor r p5 Second resistor r p2 and the third resistor r p3 ; transistor Q lp11 The base is connected to node a3, the collector to node a4, and the emitter to node a10; transistor Q n12 The base is connected to node a4, the collector is connected to node a4, and the emitter is connected to node GND; transistor Q lp12 The base is connected to node a8, the collector to node a7, and the emitter to node a11; transistor Q n13 The base is connected to node a4, the collector to node a7, and the emitter to node GND; transistor Q n7 The base is connected to node a7, the collector is connected to node a7, and the emitter is connected to node a12; the fifth resistor r p5 One end is connected to node a12, and the other end is connected to node GND; the second resistor r p2 One end is connected to node a9, and the other end is connected to node a10; the third resistor r p3 One end is connected to node a9, and the other end is connected to node a11.

5. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 4, characterized in that, The second differential amplifier includes transistor Q. lp10 transistor Q n10 transistor Q lp9 transistor Q n11 transistor Q n8 Fourth resistor r p4 Second resistor r p2 and the third resistor r p3 ; transistor Q lp10 The base is connected to node a8, the collector to node a6, and the emitter to node a11; transistor Q n10 The base is connected to node a6, the collector is connected to node a6, and the emitter is connected to node GND; transistor Q lp9 The base is connected to node a3, the collector to node a5, and the emitter to node a10; transistor Q n11 The base is connected to node a6, the collector to node a5, and the emitter to node GND; transistor Q n8 The base is connected to node a5, the collector to node a5, and the emitter to node a13; the fourth resistor r p4 One end is connected to node a13, and the other end is connected to node GND.

6. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 1, characterized in that, When the linear regulator is under no-load or light-load conditions, the current of the output power transistor is small.

7. The low-dropout broadband linear regulator with low-voltage input-output characteristics according to claim 1, characterized in that, When the linear regulator is under full or heavy load, the current of the output power transistor is large.

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