An adaptive low-dropout linear regulator with low power consumption and fast transient response

Abstract

The application discloses a low-power-consumption fast transient response adaptive low-dropout linear voltage regulator and belongs to the technical field of integrated circuit design. The voltage regulator is realized based on a three-stage STCB structure circuit with a switch, the maximum value of overshoot or undershoot of output voltage VOUT when a load current changes is compared with a preset voltage range through a detection circuit, and the number of stages of the STCB structure circuit is adjusted according to the detection result of the detection circuit through a digital logic control module, so that the load regulation rate and the linear regulation rate of the LDO are further improved. In addition, the fast transient response LDO with the switch can adjust the number of STCB stages adaptively according to the detection result, so that the LDO has lower power consumption under the condition of good transient response performance.

Description

TECHNICAL FIELD

[0001] The application relates to a low-power-consumption fast-transient-response adaptive low-dropout linear voltage regulator and belongs to the technical field of integrated circuit design. BACKGROUND

[0002] A low-dropout linear voltage regulator (LDO) is a device for stabilizing an input voltage at a desired output voltage level, and the core function thereof is to provide a stable reference voltage, so as to realize the stabilization of an output voltage through an internal error amplifier, a power transistor and a feedback network. The LDO can provide a stable and almost ripple-free output voltage, has the advantages of simple structure, low power consumption, low high-frequency noise, small size and easy integration, and plays an important role in a modern power management unit and is widely applied to electronic equipment.

[0003] In order to save power consumption in a circuit system, a circuit module that is temporarily not in operation is usually required to be in a shutdown or sleep mode, and once started, the power supply voltage can be stabilized in a very short time, which is usually in the order of microseconds or nanoseconds, so that the power supply module still has good voltage stabilization capability when the full load range jumps. However, in the LDO loop, due to the limitation of bandwidth and slew rate, the loop needs a certain adjustment time when the load current transiently jumps, and the external performance is that the output voltage has a short-term overshoot and undershoot, and even a short-time oscillation phenomenon occurs, so it is particularly important to improve the transient response.

[0004] Common techniques for enhancing the transient response of an LDO include: 1) increasing the static current of the LDO system, especially the drive current of the power tube gate, so that when the load current transiently jumps, the power transistor can provide the required current faster, thereby reducing the fluctuation of the output voltage. 2) reducing the size of the power tube in the LDO structure and increasing the voltage swing of the power tube gate, so that the power tube can reach its conduction state in a shorter time and quickly provide the required output current. However, the above-mentioned method of increasing the static current can effectively reduce the undershoot voltage and overshoot voltage, but it will increase the system power consumption, which does not meet the development trend of low power consumption of the LDO chip. The method of appropriately reducing the size of the power tube and increasing the voltage swing of the power tube gate can improve the transient response performance of the LDO to a certain extent, but the improvement is very limited.

[0005] To solve the above problems, Du Yan of Xi'an University of Technology proposed a slice-free capacitor LDO with fast transient response characteristics in 2021, which uses an adaptive boost circuit with simple structure and does not consume excessive static current during operation, but its input voltage range is small, the layout area is large, and it does not have obvious advantages in power consumption. The Chinese patent with publication number CN105094199A proposes a low-power low-noise low-dropout linear voltage regulator, which can maintain high gain while still having low power consumption and low noise, but it does not have a breakthrough in transient response. The Chinese patent with publication number CN208848104U proposes a fast transient response low-dropout linear regulator, which enhances the load transient response of the regulator with a load transient response enhancement circuit. In the absence of an external capacitor, the load transient response performance of the low-dropout linear regulator is improved, but it still cannot demonstrate its advantages in power consumption. SUMMARY

[0006] To improve the transient response of the LDO while reducing its power consumption, the present application provides a low-power fast transient response adaptive low-dropout linear regulator, which improves the existing STCB circuit scheme to improve the transient response and greatly reduces the power consumption while ensuring the transient response performance.

[0007] A low-power fast transient response adaptive low-dropout linear regulator, comprising an operational amplifier, a feedback network, a three-stage STCB structure circuit with a switch, a digital logic control module, and a detection module, wherein the detection module is provided with a comparator for comparing the size of the output voltage of the regulator with the reference voltage set internally; the digital logic control module is provided with a corresponding counter and a register for adjusting the number of stages of the three-stage STCB structure circuit according to the detection result of the detection module.

[0008] Optionally, the operational amplifier includes two-stage operational circuit, and the three-stage STCB structure circuit with a switch is between the two-stage operational circuit; the detection module is provided with two comparators to compare the maximum value Vmax of the overshoot and undershoot of the power tube output voltage with the preset voltage.

[0009] Optionally, the digital logic control module is composed of a counter and a register, and a digital trimming module is used to control the switch to reduce or increase the number of stages of the STCB structure.

[0010] Optionally, the three-stage STCB structure circuit with switches comprises a first-stage STCB structure circuit, a second-stage STCB structure circuit and a third-stage STCB structure circuit; each stage of the STCB structure circuit is divided into an upper part and a lower part, wherein the upper part of the first-stage STCB structure circuit is composed of transistors M5-M9, and the lower part is composed of transistors M22-M26; the upper part of the second-stage STCB structure circuit is composed of transistors M10-M14, and the lower part is composed of transistors M27-M31; the upper part of the third-stage STCB structure circuit is composed of transistors M15-M19, and the lower part is composed of transistors M32-M36M38;

[0011] The transistors M55, M43, M47 constitute a switch S1; the transistors M41, M42, M44, M45, M46, M48, M51, M54 constitute a switch S2; the transistors M41, M42, M44, M46, M49, M50, M52, M53 constitute a switch S3;

[0012] The transistor M55 in the switch S1 is connected between the gate of the transistor M9 in the upper part of the first-stage STCB circuit and the gate of the transistor M20 in the second-stage operation circuit, the transistor M43 is connected between the gate of the transistor M26 in the lower part of the first-stage STCB circuit and the gate of M37, the transistor M47 in the switch S1 is connected between the source of the transistor M46 in the switch S2 and the gate of M37, and the working of the first-stage STCB circuit is controlled;

[0013] The transistor M41 in the switch S2 is connected between the gate of the transistor M9 in the upper part of the second-stage STCB structure circuit and the gate of M10 in the switch S1, the transistor M42 is connected between the gate of the transistor M9 in the upper part of the second-stage STCB structure circuit and the gate of the transistor M12 in the upper part of the second-stage STCB structure circuit, the transistor M44 is connected between the gate of the transistor M26 in the lower part of the first-stage STCB structure circuit and the gate of the transistor M27 in the lower part of the second-stage STCB structure circuit, the transistor M46 is connected between the gate of the transistor M26 in the lower part of the first-stage STCB structure circuit and the drain of M47 in the switch S1, the transistor M45 in the switch S2 is connected between the drain of M46 and the gate of the transistor M29 in the lower part of the second-stage STCB structure circuit, the transistor M48 in the switch S2 is connected between the gate of the transistor M16 in the upper part of the third-stage STCB structure circuit and the gate of the transistor M20 in the output amplification circuit, the transistor M51 in the switch S2 is connected between the source of M49 and the gate of the transistor M20 in the output amplification circuit, the transistor M54 in the switch S2 is connected between the gate of the transistor M31 in the lower part of the second-stage STCB structure circuit and the gate of the transistor M21 in the output amplification circuit, and the working of the second-stage STCB structure circuit is controlled;

[0014] The transistor M49 in the switch S3 is connected between the gate of the transistor M16 at the upper part of the third-stage STCB structure circuit and the drain of the transistor M51 in the switch S2, the transistor M50 in the switch S3 is connected between the drain of the transistor M49 and the gate of the transistor M35 at the lower part of the third-stage STCB structure circuit, the transistor M52 in the switch S3 is connected between the gate of the transistor M31 at the lower part of the second-stage STCB structure circuit and the gate of the transistor M34 at the lower part of the third-stage STCB structure circuit, the transistor M53 in the switch S3 is connected between the gate of the transistor M31 at the lower part of the second-stage STCB structure circuit and the gate of the transistor M32 at the lower part of the third-stage STCB structure circuit, and the work of the third-stage STCB structure circuit is controlled.

[0015] Optionally, the gates of the transistors M55, M43 and M47 in the switch S1 are connected to the signal clk1, the gates of the transistors M41, M42, M44, M45 and M46 in the switch S2 are connected to the signal clk2, the gates of the transistors M48, M51 and M54 in the switch S3 are connected to the signal clk3, and the gates of the transistors M49, M50, M52 and M53 are connected to the signal clk4; the gate voltages of the transistors are controlled by the digital signals clk1, clk2, clk3 and clk4, and the on-off of the switches is further controlled.

[0016] Optionally, the working process of the voltage stabilizer comprises:

[0017] (1) preparation stage, the circuits of the voltage stabilizer are reset, and the register configuration in the digital logic control module is in the default state;

[0018] (2) start-up stage: the circuits of the voltage stabilizer are started, when the load current changes, the output voltage Vout of the power tube changes correspondingly, the two comparators of the detection module compare the output voltage Vout with the preset voltages VH and VL, wherein the preset voltages VH and VL are the threshold values of overshoot and undershoot respectively:

[0019] If the maximum value Vmax of the overshoot / undershoot of the output voltage Vout is less than the preset voltage VH and greater than the preset voltage VL, i.e. VL < Vmax < VH, the first comparator outputs C1 = 0, and the second comparator outputs C2 = 0; the maximum value Vmax of the overshoot / undershoot of the output voltage Vout is within the normal range, and the circuit works normally;

[0020] If the maximum value of the undershoot of the output voltage Vout is less than the preset voltage VL, i.e. Vmax < VL, the first comparator outputs C1 = 1, and the second comparator outputs C2 = 0; at this time, the first counter starts counting when the first comparator outputs C1 = 1 is detected;

[0021] If the maximum value of the overshoot of the output voltage Vout is greater than the preset voltage VH, that is, Vmax>VH, the second comparator outputs C2=1 and the first comparator outputs C1=0; at this time, the second counter detects the second comparator output C2=1 and starts counting.

[0022] Optionally, the count values ​​N1 and N2 of the first counter and the second counter are determined by the counter operating frequency, the difference between the maximum value Vmax of the overshoot / undershoot of the output voltage Vout and a preset voltage, and the digital logic control module controls the switch according to the count values ​​of the two to reduce or increase the number of stages of the STCB structure:

[0023] like Then the control switch S1 is closed, the switches S2 and S3 are opened, the first-level STCB structure circuit is in the working state, and the second-level and third-level STCB structure circuits are in the non-working state;

[0024] like Then the control switches S1 and S2 are closed and the switch S3 is opened, the first and second stage STCB structure circuits are in working state, and the third stage STCB structure circuit is in non-working state;

[0025] like Then the control switches S2 and S3 are closed, the switch S1 is opened, and the first-stage, second-stage and third-stage STCB structure circuits are all in working state.

[0026] The beneficial effects of the present invention are:

[0027] First, the proposed detection circuit compares the maximum overshoot or undershoot of the output voltage VOUT during load current changes with a preset voltage range. This control circuit then adaptively adjusts the level of the STCB structure, further improving the LDO's load and line regulation. Second, the proposed fast-transient-response LDO with a switch can adjust the number of STCB stages based on the detection results, resulting in lower power consumption while maintaining good transient response performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a structural diagram of a fast transient response low-dropout linear regulator with a switch and a control circuit thereof proposed by the present invention.

[0030] Figure 2This is a circuit diagram of an existing operational amplifier circuit and an STCB structure.

[0031] Figure 3 This is a circuit diagram of the operational amplifier circuit and the STCB structure with a switch proposed by the present invention.

[0032] Figure 4A This is a transient simulation performance diagram of a fast transient response low-dropout linear regulator with a one-stage STCB structure having a switch proposed by the present invention;

[0033] Figure 4B This is a transient simulation performance diagram of a fast transient response low-dropout linear regulator with a two-stage STCB structure having a switch proposed by the present invention;

[0034] Figure 4C This is a transient simulation performance diagram of a fast transient response low-dropout linear regulator with a three-stage STCB structure and switches proposed by the present invention;

[0035] Figure 4D This is a transient simulation performance diagram of the low-dropout linear regulator with fast transient response of the switch proposed by the present invention.

[0036] Figure 5 This is a power consumption diagram of the low-dropout linear regulator with fast transient response of the switch proposed by the present invention. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0038] Example 1:

[0039] This embodiment provides a low-power, fast-transient-response adaptive low-dropout linear regulator. Figure 1 , including: an operational amplifier, a feedback loop, a three-stage STCB structure circuit with a switch, a digital logic control module and a detection module; wherein the operational amplifier, the three-stage STCB structure circuit with a switch and the power tube are connected in sequence, and the feedback loop connects the output end of the power tube and one of the input ends of the operational amplifier; the output end of the power tube is also connected to the detection module so that the detection module compares the maximum value Vmax of the overshoot and undershoot of the output voltage with a preset voltage, and the output end of the detection module is connected to the digital logic control module so that the digital logic control module adjusts the number of stages of the three-stage STCB structure circuit with a switch according to the output of the detection module.

[0040] like Figure 2 As shown, there is an existing operational amplifier circuit and an STCB structure circuit, wherein the STCB structure circuit is a three-stage STCB structure circuit. Figure 3From the circuit diagram of the STCB structure with switches proposed in the present invention, it can be seen that the present application adds corresponding switches to each level of the STCB circuit on the basis of the existing STCB structure circuit structure, and designs a detection module and a digital logic control module based on the STCB structure circuit with switches. By detecting the comparison between the maximum value of the overshoot and undershoot of the output voltage and the preset voltage, the adaptive adjustment of the STCB circuit level is realized based on the switch, thereby reducing the circuit power consumption as much as possible while ensuring the transient response performance.

[0041] like Figure 1 As shown, the detection module is provided with two comparators, which are used to compare the maximum value Vmax of the overshoot and undershoot of the output voltage with the preset voltage; the digital logic control module is provided with corresponding counters and registers, which are used to adjust the number of levels of the three-stage STCB structure circuit according to the detection results of the detection module.

[0042] like Figure 3 As shown, the operational amplifier includes two operational circuits, with a three-stage STCB structure circuit with switches positioned between them. The first operational circuit includes a bias circuit and an input amplifier circuit, while the second operational circuit includes an output amplifier circuit. The bias circuit consists of a current source and transistor M39. The current source is connected between transistor M39 and ground to ensure that the bias point of the operational amplifier is within an appropriate range, thereby ensuring circuit linearity and stability. The input amplifier circuit consists of transistors M1-M4. Transistors M1 and M2 form a PMOS differential input pair. The differential input structure can better suppress common-mode interference. The drain of transistor M40 is connected to the sources of transistors M1 and M2, providing a constant bias current for the first amplifier stage. Transistors M3 and M4 form a current mirror as an active load. The output amplifier circuit consists of transistors M20 and M21, further increasing the circuit's gain.

[0043] See Figure 2The main circuit of the STCB structure is connected between a differential input stage formed by transistors M1-M4 and an output stage composed of transistors M20 and M21, and contains a first-stage STCB structure circuit, a second-stage STCB structure circuit and a third-stage STCB structure circuit. Each stage of the STCB structure circuit is divided into an upper part and a lower part, and the upper parts of the stages are cascaded to form the upper part of the entire STCB structure circuit, and the lower parts of the stages are cascaded to form the lower part of the entire STCB structure circuit. The upper part of the first-stage STCB structure circuit is composed of transistors M5-M9, and the lower part is composed of transistors M22-M26; the upper part of the second-stage STCB structure circuit is composed of transistors M10-M14, and the lower part is composed of transistors M27-M31; the upper part of the third-stage STCB structure circuit is composed of transistors M15-M19, and the lower part is composed of transistors M32-M38; the upper parts of the transistors M5-M9, M10-M14 and M15-M19 are cascaded to form the upper part of the three-stage STCB structure circuit, and the lower parts of the transistors M22-M26, M27-M31 and M32-M38 are cascaded to form the lower part of the three-stage STCB structure circuit. The connection relationship of the transistors in each part is described in detail below:

[0044] The first-stage STCB structure circuit: in the input amplification circuit of the first-stage operation circuit, the gate and drain of transistor M4 are connected, and the gate thereof is connected with the gates of transistors M5 and M7 in the upper part of the first-stage STCB circuit to form two current mirrors, and the size ratio of transistors M4, M5 and M7 is 1:1:k+1 (k>1). Similarly, in the input amplification circuit of the first-stage operation circuit, the gate and drain of transistor M3 are connected, and the gate thereof is connected with the gates of transistors M22 and M24 in the lower part of the first-stage STCB circuit to form two current mirrors, and the size ratio of transistors M3, M22 and M24 is 1:1:k+1 (k>1); the gate and drain of transistor M6 in the upper part of the first-stage STCB circuit are connected, and the gate thereof is connected with the gate of transistor M25 in the lower part of the first-stage STCB circuit to form a current mirror, and the size ratio of transistors M6 and M25 is 1:k; the gate and drain of transistor M23 in the lower part of the first-stage STCB circuit are connected, and the gate thereof is connected with the gate of transistor M8 to form a current mirror, and the size ratio of transistors M23 and M8 is 1:k (k>1). At the same time, the drain of transistor M5 in the upper part of the first-stage STCB circuit is connected with the drain of transistor M6, the drain of transistor M7 in the upper part of the first-stage STCB circuit is connected with the drains of transistors M8 and M9, the drain of transistor M22 in the lower part of the first-stage STCB circuit is connected with the drain of transistor M23, the drain of transistor M24 in the lower part of the first-stage STCB circuit is connected with the drains of transistors M25 and M26, and transistors M8, M9, M25 and M26 form a differential pair.

[0045] Second-stage STCB structure circuit: The gate of transistor M9 at the top of the first-stage STCB structure circuit is connected to the gates of transistors M10 and M12 at the top of the second-stage STCB structure circuit to form two current mirrors. The size ratio of transistors M9, M10, and M12 is 1:1:k+1 (k>1). Similarly, the gate of transistor M26 at the bottom of the first-stage STCB structure circuit is connected to the gates of transistors M27 and M29 at the bottom of the second-stage STCB structure circuit to form two current mirrors. The size ratio of transistors M26, M27, and M29 is 1:1:k+1 (k>1). The drain of transistor M10 in the upper portion of the second-stage STCB structure circuit is connected to the drain of transistor M11. The gate and drain of transistor M11 in the upper portion of the second-stage STCB structure circuit are connected, and its gate is connected to the gate of transistor M30 in the lower portion to form a current mirror. The size ratio of transistors M11 and M30 is 1:k. The drain of transistor M27 in the lower portion of the second-stage STCB structure circuit is connected to the drain of transistor M28. The gate and drain of transistor M28 are connected, and its gate is connected to the gate of transistor M13 in the upper portion of the second-stage STCB structure circuit to form a current mirror. The size ratio of transistors M28 and M13 is 1:k (k>1). At the same time, the drain of transistor M12 in the upper portion of the second-stage STCB structure circuit is connected to the drains of transistors M13 and M14. Transistors M13 and M14 form a differential pair. The drain of transistor M29 in the lower portion of the second-stage STCB structure circuit is connected to the drains of transistors M30 and M31. Transistors M30 and M31 form a differential pair.

[0046] The gate of the transistor M14 in the upper half of the upper part of the third-stage STCB structure circuit is connected with the gates of the transistors M15 and M17 in the upper part of the third-stage STCB structure circuit to form two current mirrors, and the size ratio of the transistors M14, M15 and M17 is 1:1:k+1 (k>1). Similarly, the gate of the transistor M31 in the lower part of the third-stage STCB structure circuit is connected with the gates of the transistors M32 and M34 to form two current mirrors, and the size ratio of the transistors M31, M32 and M34 is 1:1:k+1 (k>1). The gate of the transistor M16 in the upper part of the second-stage STCB structure circuit is connected with the gate of the transistor M35 in the lower part of the third-stage STCB structure circuit to form a current mirror, and the size ratio of the transistors M16 and M35 is 1:k. The gate of the transistor M33 in the lower part of the third-stage STCB structure circuit is connected with the gate of the transistor M18 in the upper part of the second-stage STCB structure circuit to form a current mirror, and the size ratio of the transistors M33 and M18 is 1:k (k>1). Meanwhile, the drain of the transistor M16 in the upper part of the second-stage STCB structure circuit is connected with the drain of the transistor M15, the drain of the transistor M17 is connected with the drains of the transistors M18 and M19, and the transistors M18 and M19 form a differential pair. The drain of the transistor M32 in the lower part of the third-stage STCB structure circuit is connected with the drain of the transistor M33, the drain of the transistor M34 is connected with the drains of the transistors M35 and M36, and the transistors M35 and M36 form a differential pair. The gate of the transistor M36 is connected with the drain of the transistor M36, the gate of the transistor M37 is connected with the gate of the transistor M36, and a current mirror is formed. The transistor M38 is connected between the drain of the transistor M37 and the ground.

[0047] As Figure 3As shown, the low-dropout linear regulator with switches provided by the application adds switches to each stage of the STCB circuit, wherein the transistor M55, M43, M47 serves as switch S1; the transistor M41, M42, M44, M45, M46, M48, M51, M54 serves as switch S2; the transistor M41, M42, M44, M46, M49, M50, M52, M53 serves as switch S3. The transistor M55 in switch S1 is connected between the gate of transistor M9 at the upper part of the first stage STCB circuit and the gate of transistor M20 in the second stage operational circuit, the transistor M43 is connected between the gate of transistor M26 at the lower part of the first stage STCB circuit and the gate of M37, the transistor M47 in switch S1 is connected between the source of transistor M46 in switch S2 and the gate of M37, and controls the operation of the first stage STCB circuit. The transistor M41 is connected between the gate of transistor M9 at the upper part of the second stage STCB structure circuit and the gate of M10 in switch S1, the transistor M42 is connected between the gate of transistor M9 at the upper part of the second stage STCB structure circuit and the gate of transistor M12 at the upper part of the second stage STCB structure circuit, the transistor M44 is connected between the gate of transistor M26 at the lower part of the first stage STCB structure circuit and the gate of transistor M27 at the lower part of the second stage STCB structure circuit, the transistor M46 is connected between the gate of transistor M26 at the lower part of the first stage STCB structure circuit and the drain of M47 in switch S1, the transistor M45 in switch S2 is connected between the drain of M46 and the gate of transistor M29 at the lower part of the second stage STCB structure circuit, the transistor M48 in switch S2 is connected between the gate of transistor M16 at the upper part of the third stage STCB structure circuit and the gate of transistor M20 in the output amplification circuit, the transistor M51 in switch S2 is connected between the source of M49 and the gate of transistor M20 in the output amplification circuit, the transistor M54 in switch S2 is connected between the gate of transistor M31 at the lower part of the second stage STCB structure circuit and the gate of transistor M21 in the output amplification circuit, and controls the operation of the second stage STCB structure circuit. The transistor M49 in switch S3 is connected between the gate of transistor M16 at the upper part of the third stage STCB structure circuit and the drain of transistor M51 in switch S2, the transistor M50 in switch S3 is connected between the drain of M49 and the gate of transistor M35 at the lower part of the third stage STCB structure circuit, the transistor M52 in switch S3 is connected between the gate of transistor M31 at the lower part of the second stage STCB structure circuit and the gate of transistor M34 at the lower part of the third stage STCB structure circuit, the transistor M53 in switch S3 is connected between the gate of transistor M31 at the lower part of the second stage STCB structure circuit and the gate of transistor M32 at the lower part of the third stage STCB structure circuit, and controls the operation of the third stage STCB structure circuit.When the transistors M55, M43, and M47 that constitute switch S1 are turned on and the transistors that constitute switches S2 and S3 are turned off, the first-level STCB structure circuit works; when the transistors M41, M42, M44, M45, M46, M48, M51, and M54 that constitute switch S2 are turned on and the transistors that constitute switches S1 and S3 are turned off, the second-level STCB structure circuit works; when the transistors M41, M42, M44, M46, M49, M50, M52, and M53 that constitute switch S3 are turned on and the transistors that constitute switches S1 and S2 are turned off, the third-level STCB structure circuit works.

[0048] The gates of transistors M55, M43, and M47 in switch S1 are connected to signal clk1, the gates of M41, M42, M44, M45, and M46 in switch S2 are connected to signal clk2, the gates of M48, M51, and M54 in switch S3 are connected to signal clk3, and M49, M50, M52, and M53 are connected to signal clk4.

[0049] Example 2:

[0050] This embodiment provides a control method for an adaptive low-dropout linear regulator with low power consumption and fast transient response, which is implemented based on the adaptive low-dropout linear regulator provided in the first embodiment.

[0051] like Figure 1 As shown, in the adaptive low-dropout linear regulator provided in Example 1, the detection module consists of a first comparator and a second comparator; the digital logic control module consists of a counter, a register, etc. The comparator is connected to the counter; the digital logic control module is connected to switches S1, S2, and S3, and adjusts the number of stages of the STCB structure circuit by controlling the opening and closing of the switches.

[0052] The operating principle of the present invention is as follows: a digital logic control module, consisting of a counter and registers, combined with a digital trimming module, controls switches to reduce or increase the number of stages in the STCB structure. C1 and C2 are the code values ​​output by the first and second comparators. After the circuit is activated, the digital logic circuit quantifies the disturbance to the output voltage settling time based on the output of the detection module and adjusts the number of STCB stages based on the magnitude of the disturbance.

[0053] The control method of the adaptive low-dropout linear regulator with low power consumption and fast transient response provided by this embodiment includes:

[0054] (1) Preparation stage: All circuits are reset and register configurations are in default state.

[0055] (ii) Start-up phase: the circuit starts, when the load current changes, the power tube output voltage Vout corresponding changes, the detection module of two comparators will output voltage Vout and the preset voltage VH and VL comparison, wherein the preset voltage VH and VL are overshoot and undershoot threshold value respectively:

[0056] If the maximum value of the output voltage Vout overshoot / undershoot Vmax is less than the preset voltage VH and greater than the preset voltage VL, that is, VL < Vmax < VH, the first comparator output C1 = 0, the second comparator output C2 = 0; the maximum value of the output voltage Vout overshoot / undershoot Vmax is in the normal range, the circuit works normally.

[0057] If the maximum value of the output voltage Vout undershoot is less than the preset voltage VL, that is, Vmax < VL, the first comparator output C1 = 1, the second comparator output C2 = 0; at this time the first counter starts counting when the first comparator output C1 = 1 is detected.

[0058] If the maximum value of the output voltage Vout overshoot is greater than the preset voltage VH, that is, Vmax > VH, the second comparator output C2 = 1, the first comparator output C1 = 0; at this time the second counter starts counting when the second comparator output C2 = 1 is detected.

[0059] The output of the first counter is N1, and the output of the second counter is N2. Subsequently, the counter outputs the code value to the register, and the register is configured by ctr_reg<3,0>. The register drives the switch to adjust the number of stages of the STCB structure circuit in combination with the digital trimming module.

[0060] For example, the initial state is: switches S1 and S2 are closed, switch S3 is open (that is, clk1 = 0, clk2 = 1, clk3 = 1, clk4 = 0), and the register state is ctr_reg<3,0> = 1000. The two-stage STCB structure circuit is in working state.

[0061] The count values N1 and N2 of the first counter and the second counter are determined by the working frequency of the counter, the maximum value Vmax of the output voltage Vout overshoot / undershoot, and the difference between the preset voltage. The specific adjustment algorithm is:

[0062] If At this time, the LDO has good transient response performance, and the LDO output voltage Vout is stable in a short time when the load changes; at this time, the register state changes from ctr_reg<3,0>=1000 to ctr_reg<3,0>=0111, and the switch S1 is closed, the switches S2 and S3 are disconnected (i.e., clk1=1, clk2=0, clk3=0, clk4=0) through the assistance of the digital Triming module, the first-stage STCB structure circuit is in the working state, and the second-stage and third-stage STCB structure circuits are in the non-working state, so that the power consumption of the circuit is further reduced, the LDO has good transient response performance, and the power consumption is low.

[0063] If At this time, the LDO has good transient response performance and low power consumption, the register state is unchanged, the LDO main circuit STCB structure circuit configuration is unchanged, the switches S1 and S2 are closed, and the switch S3 is disconnected (i.e., clk1=0, clk2=1, clk3=1, clk4=0), the register state is ctr_reg<3,0>=1000, the first-stage and second-stage STCB structure circuits are in the working state, and the third-stage STCB structure circuit is in the non-working state.

[0064] If At this time, the LDO has poor transient response performance, and the LDO output voltage Vout is stable in a slow time when the load changes, so that the STCB structure circuit needs to be adjusted to the third stage to speed up the stable time, the register state changes from ctr_reg<3,0>=1000 to ctr_reg<3,0>=1001, and the switches S2 and S3 are closed and the switch S1 is disconnected (i.e., clk1=0, clk2=1, clk3=0, clk4=1) through the assistance of the digital Triming module.

[0065] Further, please refer to Figure 4A , a transient simulation performance diagram of the LDO with the first-stage STCB structure circuit for fast transient response, Figure 4B , a transient simulation performance diagram of the LDO with the second-stage STCB structure circuit for fast transient response, Figure 4C , a transient simulation performance diagram of the LDO with the third-stage STCB structure circuit for fast transient response. Figure 4D , a comparison diagram of transient simulation results of the LDO with the circuits at different stages for fast transient response, according to Figures 4A-4D It can be seen that:

[0066] When the load current is adjusted from 10mA to 20mA at 5us, the maximum undershoot voltage of the output voltage of the first STCB structure circuit is 1.32V, the stable time is 512ns, and the transient response is 0.051us / mA; when the load current is adjusted from 20mA to 10mA at 5us, the maximum overshoot voltage of the output voltage of the first STCB structure circuit is 1.5V, the stable time is 1.2us, and the transient response is 0.12us / mA.

[0067] When the load current is adjusted from 10mA to 20mA at 5us, the maximum undershoot voltage of the output voltage of the second STCB structure circuit is 1.31V, the stable time is 301ns, and the transient response is 0.031us / mA; when the load current is adjusted from 20mA to 10mA at 5us, the maximum overshoot voltage of the output voltage of the second STCB structure circuit is 1.48V, the stable time is 127ns, and the transient response is 0.012us / mA.

[0068] When the load current is adjusted from 10mA to 20mA at 5us, the maximum undershoot voltage of the output voltage of the third STCB structure circuit is 1.30V, the stable time is 156ns, and the transient response is 0.015us / mA; when the load current is adjusted from 20mA to 10mA at 5us, the maximum overshoot voltage of the output voltage of the third STCB structure circuit is 1.48V, the stable time is 172ns, and the transient response is 0.017us / mA. It has good transient response performance.

[0069] Further, please refer to Figure 5 , Figure 5 The power consumption diagram of the low-dropout linear regulator with fast transient response of the application. The first STCB structure LDO has simple structure, small area, low static current and lowest power consumption; the second STCB structure LDO has larger area, more MOS tubes, more complex connection, increased static current and increased power consumption compared with the first STCB structure LDO; the third STCB structure LDO contains more elements, has the largest area and the most complex structure, and the static current also increases linearly, so the power consumption of the third STCB structure LDO is increased compared with the second STCB structure LDO; therefore, the power consumption of the LDO with the first STCB structure to the LDO with the third STCB structure increases gradually. The static power consumption of the circuit system can be calculated by the formula: static =V cc ×I staticWhen the power supply voltage is 1.8V and the load current is 20mA, the static current of the first-stage STCB structure circuit system is 98.3μA, and the power consumption is 0.17mW. The static current of the second-stage STCB structure circuit system is 136.4μA, and the power consumption is 0.24mW. The static current of the third-stage STCB structure circuit system is 232.7μA, and the power consumption is 0.41mW. Compared with the power consumption of the similar structure LDO which is 0.36mW, the power consumption of the LDO circuit system of the present application is smaller, and the transient response performance is superior to the similar structure LDO, so that the compromise between the power consumption and the transient response performance can be realized.

[0070] Part of the steps in the embodiments of the present application can be realized by software, and the corresponding software program can be stored in a readable storage medium, such as an optical disc or a hard disk.

[0071] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An adaptive low-dropout linear regulator with low power consumption and fast transient response, characterized in that: The voltage regulator includes: an operational amplifier, a feedback loop, a three-stage STCB structure circuit with a switch, a power tube, a digital logic control module and a detection module; wherein the operational amplifier, the three-stage STCB structure circuit with a switch and the power tube are connected in sequence, and the feedback loop connects the output end of the power tube and one of the input ends of the operational amplifier; the output end of the power tube is also connected to the detection module, and the output end of the detection module is connected to the digital logic control module, so that the digital logic control module adjusts the number of stages of the three-stage STCB structure circuit with a switch according to the output of the detection module; The three-level STCB structure circuit with a switch includes a first-level STCB structure circuit, a second-level STCB structure circuit and a third-level STCB structure circuit; each level STCB structure circuit is divided into an upper part and a lower part, wherein the upper part of the first-level STCB structure circuit is composed of transistors M5-M9, and the lower part is composed of transistors M22-M26; the upper part of the second-level STCB structure circuit is composed of transistors M10-M14, and the lower part is composed of transistors M27-M31; the upper part of the third-level STCB structure circuit is composed of transistors M15-M19, and the lower part is composed of transistors M32-M38; the transistors M5-M9, the transistors M10-M14 and the transistors M15-M19 are cascaded to form the upper part of the three-level STCB structure circuit, and the transistors M22-M26, the transistors M27-M31 and the transistors M32-M38 are cascaded to form the lower part of the three-level STCB structure circuit; First-stage STCB structure circuit: the active load of the operational amplifier includes transistors M3 and M4, the gate and drain of transistor M4 are connected, and its gate is connected to the gates of transistors M5 and M7 to form two current mirrors; the gate and drain of transistor M3 are connected, and its gate is connected to the gates of transistors M22 and M24 to form two current mirrors; the gate and drain of transistor M6 are connected, and its gate is connected to the gate of transistor M25 to form a current mirror; the gate and drain of transistor M23 are connected, and its gate is connected to the gate of transistor M8 to form a current mirror; the drain of transistor M5 is connected to the drain of transistor M6, the drain of transistor M7 is connected to the drains of transistors M8 and M9, the drain of transistor M22 is connected to the drain of transistor M23, the drain of transistor M24 is connected to the drains of transistors M25 and M26, and transistors M8, M9, M25, and M26 form a differential pair; Second-level STCB structure circuit: the gate of the transistor M9 in the upper part of the first-level STCB structure circuit is connected to the gates of the transistors M10 and M12 to form two current mirrors, the gate of the transistor M26 in the lower part of the first-level STCB structure circuit is connected to the gates of the transistors M27 and M29 to form two current mirrors, the drain of the transistor M10 is connected to the drain of the transistor M11, the gate and drain of the transistor M11 are connected, and its gate is connected to the gate of the lower-half transistor M30 to form a current mirror; the drain of the transistor M12 is connected to the drains of the transistors M13 and M14, and the transistors M13 and M14 form a differential pair; the drain of the transistor M27 is connected to the drain of the transistor M28, the gate and drain of the transistor M28 are connected, and its gate is connected to the gate of the transistor M13 to form a current mirror, the drain of the transistor M29 is connected to the drains of the transistors M30 and M31, and the transistors M30 and M31 form a differential pair; The third-level STCB structure circuit: the gate of the transistor M14 at the upper part of the second-level STCB structure circuit is connected to the gates of the transistors M15 and M17 to form two current mirrors, and the gate of the transistor M31 at the lower part of the second-level STCB structure circuit is connected to the gates of the transistors M32 and M34 to form two current mirrors; the gate and drain of the transistor M16 are connected, and its gate is connected to the gate of the transistor M35 to form a current mirror, the gate and drain of the transistor M33 are connected, and its gate is connected to the gate of the transistor M18 to form a current mirror; the transistor M16 The drain of transistor M32 is connected to the drain of transistor M33, the drain of transistor M34 is connected to the drains of transistors M35 and M36, and transistors M35 and M36 form a differential pair; the gate and drain of transistor M36 are connected, and the gate of transistor M37 is connected to the gate of transistor M36, forming a current mirror; transistor M38 is connected between the drain of transistor M37 and ground.

2. The voltage stabilizer according to claim 1, wherein: The operational amplifier includes a two-stage operational circuit, and the three-stage STCB structure circuit with a switch is located between the two-stage operational circuit; the detection module is provided with two comparators to compare the maximum value Vmax of the overshoot and undershoot of the power tube output voltage with the preset voltage.

3. The voltage stabilizer according to claim 2, wherein: The digital logic control module is composed of a counter and a register, and uses a digital trimming module to control switches to reduce or increase the number of stages of the STCB structure.

4. The voltage stabilizer according to claim 3, wherein: Transistors M55, M43, and M47 form a switch S1; transistors M41, M42, M44, M45, M46, M48, M51, and M54 form a switch S2; transistors M41, M42, M44, M46, M49, M50, M52, and M53 form a switch S3; In the first-stage STCB structure circuit, the source of transistor M46 is connected to the drain of transistor M24; The transistor M55 in the switch S1 is connected between the gate of the transistor M9 in the upper part of the first-stage STCB circuit and the gate of the transistor M20 in the second-stage operation circuit. The transistor M43 is connected between the gate of the transistor M26 and the gate of M37 in the lower part of the first-stage STCB circuit. The transistor M47 in the switch S1 is connected between the source of the transistor M46 and the gate of M37 in the switch S2 to control the operation of the first-stage STCB circuit. The transistor M41 in the switch S2 is connected between the gate of the transistor M9 at the upper part of the second-level STCB structure circuit and the gate of M10 in the switch S1, the transistor M42 is connected between the gate of the transistor M9 at the upper part of the second-level STCB structure circuit and the gate of the transistor M12 at the upper part of the second-level STCB structure circuit, the transistor M44 is connected between the gate of the transistor M26 at the lower part of the first-level STCB structure circuit and the gate of the transistor M27 at the lower part of the second-level STCB structure circuit, the transistor M46 is connected between the gate of the transistor M26 at the lower part of the first-level STCB structure circuit and the drain of M47 in the switch S1, and the switch S The transistor M45 in switch S2 is connected between the drain of M46 and the gate of the transistor M29 at the bottom of the second-stage STCB structure circuit, the transistor M48 in switch S2 is connected between the gate of the transistor M16 at the top of the third-stage STCB structure circuit and the gate of the transistor M20 in the output amplifier circuit, the transistor M51 in switch S2 is connected between the source of M49 and the gate of the transistor M20 in the output amplifier circuit, and the transistor M54 in switch S2 is connected between the gate of the transistor M31 at the bottom of the second-stage STCB structure circuit and the gate of the transistor M21 in the output amplifier circuit to control the operation of the second-stage STCB structure circuit; In the third-stage STCB structure circuit, the source of the transistor M49 is connected to the drain of the transistor M16; The transistor M49 in switch S3 is connected between the gate of the transistor M16 at the top of the third-level STCB structure circuit and the drain of the transistor M51 in switch S2, the transistor M50 in switch S3 is connected between the drain of M49 and the gate of the transistor M35 at the bottom of the third-level STCB structure circuit, the transistor M52 in switch S3 is connected between the gate of the transistor M31 at the bottom of the second-level STCB structure circuit and the gate of the transistor M34 at the bottom of the third-level STCB structure circuit, and the transistor M53 in switch S3 is connected between the gate of the transistor M31 at the bottom of the second-level STCB structure circuit and the gate of the transistor M32 at the bottom of the third-level STCB structure circuit to control the operation of the third-level STCB structure circuit.

5. The voltage stabilizer according to claim 4, characterized in that The gates of transistors M55, M43, and M47 in switch S1 are connected to signal clk1, the gates of M41, M42, M44, M45, and M46 in switch S2 are connected to signal clk2, the gates of M48, M51, and M54 in switch S3 are connected to signal clk3, and M49, M50, M52, and M53 are connected to signal clk4; the gate voltages of each transistor are controlled by digital signals clk1, clk2, clk3, and clk4, thereby controlling the on / off of each switch.

6. The voltage stabilizer according to claim 5, characterized in that The working process of the voltage regulator includes: (I) Preparation stage: Each part of the circuit of the voltage regulator is reset, and the register configuration in the digital logic control module is in the default state; (II) Startup stage: Each part of the circuit of the voltage regulator starts. When the load current changes, the output voltage Vout of the power transistor changes accordingly. Two comparators in the detection module compare the output voltage Vout with the preset voltages VH and VL, where the preset voltages VH and VL are the thresholds for overshoot and undershoot respectively: If the maximum value Vmax of the overshoot / undershoot of the output voltage Vout is less than the preset voltage VH and greater than the preset voltage VL, that is, VL < Vmax < VH, the output of the first comparator C1 = 0, and the output of the second comparator C2 = 0; the maximum value Vmax of the overshoot / undershoot of the output voltage Vout is within the normal range, and the circuit works normally; If the maximum value of the undershoot of the output voltage Vout is less than the preset voltage VL, that is, Vmax < VL, the output of the first comparator C1 = 1, and the output of the second comparator C2 = 0; at this time, the first counter starts counting when it detects that the output of the first comparator C1 = 1; If the maximum value of the overshoot of the output voltage Vout is greater than the preset voltage VH, that is, Vmax > VH, the output of the second comparator C2 = 1, and the output of the first comparator C1 = 0; at this time, the second counter starts counting when it detects that the output of the second comparator C2 = 1.

7. The voltage stabilizer according to claim 6, wherein: The counted values N1 and N2 of the first counter and the second counter are determined by the working frequency of the counter and the difference between the maximum value Vmax of the overshoot / undershoot of the output voltage Vout and the preset voltage. The digital logic control module controls the switch according to the counted values of the two to increase or decrease the number of stages of the STCB structure: like Then the control switch S1 is closed, the switches S2 and S3 are opened, the first-level STCB structure circuit is in the working state, and the second-level and third-level STCB structure circuits are in the non-working state; like Then the control switches S1 and S2 are closed and the switch S3 is opened, the first and second stage STCB structure circuits are in working state, and the third stage STCB structure circuit is in non-working state; like Then the control switches S2 and S3 are closed, the switch S1 is opened, and the first-stage, second-stage and third-stage STCB structure circuits are all in working state.

8. Application of the voltage regulator according to any one of claims 1-7 in the field of integrated circuits.

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