Low voltage drop linear regulator, chip and electronic device

Abstract

The present application provides a low-voltage difference linear regulator, a chip and an electronic device. The low-voltage difference linear regulator includes: a power tube, the first end of the power tube is connected to the power supply voltage, and the second end of the power tube outputs the target voltage; a voltage division sampling module, the voltage division sampling module is connected to the second end of the power tube to output a feedback voltage according to the target voltage; an error amplification module, the error amplification module controls the magnitude of the target voltage based on the voltage difference between the feedback voltage and the reference voltage; an anti-backflow module is connected to the source of the power tube, and the anti-backflow module is connected to the substrate of the power tube. The present application controls the substrate of the power tube to be disconnected from the source of the power tube through the anti-backflow module when the target voltage is greater than the power supply voltage, so as to avoid the phenomenon that the power tube is damaged due to current backflow during the power switching process.

Description

Technical Field

[0001] The present application relates to the technical field of integrated circuits, and in particular to a low voltage drop linear regulator, a chip and an electronic device. Background Art

[0002] Low-dropout linear regulators are a new generation of integrated circuit regulators. Because their output voltage has extremely low self-noise and high power supply rejection ratio, they are widely used in application scenarios such as smartphones, tablets, Bluetooth headsets, automobiles, wireless communications, and embedded systems.

[0003] In the related art, when an electronic device has one or more internal power sources (such as batteries) and / or is connected to one or more external power sources (such as power sources input from a TYPE-C interface), it is necessary to select one of the power sources for power supply to ensure the normal operation of the electronic device. Under normal circumstances, since the voltages of the various power inputs are not uniform, it is necessary to use multiple low-dropout linear regulators to convert the input voltages of the various power sources into target voltages. For example, a low-dropout linear regulator converts the 20V voltage input from the external TYPE-C interface into 3.3V; for another example, another low-dropout linear regulator converts the 5V voltage provided by the internal battery module into a 3.3V voltage, so as to maintain the output voltage of 3.3V and power the corresponding circuit module (such as a single-chip microcomputer).

[0004] However, when an electronic device switches from one power supply to another, current from the higher voltage power supply may flow back to the lower voltage power supply, which may cause the low dropout linear regulator to be damaged due to current backflow. Utility Model Content

[0005] In view of the above problems, the embodiments of the present application provide a low voltage dropout linear regulator, a chip and an electronic device to solve the above technical problems.

[0006] In a first aspect, an embodiment of the present application provides a low voltage dropout linear regulator, comprising:

[0007] A power tube, wherein a first end of the power tube is connected to a power supply voltage, and a second end of the power tube outputs a target voltage;

[0008] A voltage division sampling module, the voltage division sampling module is connected to the second end of the power tube to output a feedback voltage according to the target voltage;

[0009] An error amplification module, wherein the input end of the error amplification module is connected to the feedback voltage and the reference voltage, and the output end of the error amplification module is connected to the control end of the power tube to control the magnitude of the target voltage based on the voltage difference between the feedback voltage and the reference voltage;

[0010] An anti-backflow module, the anti-backflow module is connected to the source of the power tube, and the anti-backflow module is connected to the substrate of the power tube, and the source of the power tube is one of the first end of the power tube and the second end of the power tube;

[0011] When the target voltage is greater than the power supply voltage, the backflow prevention module controls the substrate of the power tube to be disconnected from the source of the power tube.

[0012] In a second aspect, an embodiment of the present application further provides a chip, comprising the above-mentioned low voltage dropout linear regulator.

[0013] In a third aspect, an embodiment of the present application further provides an electronic device, comprising the above-mentioned chip or low voltage dropout linear regulator.

[0014] The present application connects the anti-backflow module to the source of the power tube, and connects the anti-backflow module to the substrate of the power tube. When the target voltage is greater than the power supply voltage, the anti-backflow module can control the disconnection between the substrate of the power tube and the source of the power tube. At this time, the substrate of the power tube is equivalent to an empty connection, thereby changing the power tube from an on state to an off state. Therefore, it can be avoided that during the power switching process, the target voltage is greater than the power supply voltage, which causes the current to flow back through the power tube to the power supply and thus damage the power tube.

[0015] These and other aspects of the present application will become more clearly understood in the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of a low voltage dropout linear regulator in the related art is shown.

[0018] Figure 2 A power supply schematic diagram of an electronic device in the related art is shown.

[0019] Figure 3 A schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0020] Figure 4 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0021] Figure 5 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0022] Figure 6 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0023] Figure 7 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0024] Figure 8 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0025] Fig. 9 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0026] Fig.10 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0027] Fig.11 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0028] Fig.12 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0029] Fig.13 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0030] Fig.14 A schematic diagram of the second switch unit in an embodiment of the present application is shown.

[0031] Fig.15 Another schematic diagram of a low voltage dropout linear regulator in an embodiment of the present application is shown.

[0032] Fig.16 A schematic diagram of a comparison unit in an embodiment of the present application is shown.

[0033] Among them, 10 is a voltage-dividing sampling module, 20 is an error amplifying module, 30 is an anti-backflow module, 31 is a comparing unit, 32 is a first switching unit, 33 is a second switching unit, and 34 is a third switching unit;

[0034] Power tube M0, power supply voltage Vin, reference voltage Vref, feedback voltage Vfb, target voltage Vout;

[0035] A first high potential conduction transistor MP1, a first low potential conduction transistor MN1, a first node m1, a first transistor M1, a second transistor M2, a third transistor M3, a first inverter INV1, a fourth transistor M4, a fifth transistor M5, a sixth transistor M6, a first resistor R1, a second resistor R2, and an operational amplifier OP. DETAILED DESCRIPTION

[0036] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0037] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0038] In the embodiments of the present application, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0039] Moreover, the terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0040] In the description of the embodiments of the present application, words such as "example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "example" or "for example" in the embodiments of the present application is not to be interpreted as being more preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to present relative concepts in a clear manner.

[0041] In addition, the "plurality" in the embodiments of the present application refers to two or more than two. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two or more. For example, including at least one means including one, two or more, and there is no limit on which ones are included. For example, including at least one of A, B and C, then A, B, C, A and B, A and C, B and C, or A, B and C can be included.

[0042] It should be noted that, in the embodiments of the present application, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship.

[0043] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0044] The first pole / first end of each transistor used in the embodiments of the present application is one of the source and the drain, and the second pole / second end of each transistor is the other of the source and the drain. Since the source and drain of the transistor can be symmetrical in structure, the source and drain thereof can be structurally indistinguishable, that is, the first pole / first end and the second pole / second end of the transistor in the embodiments of the present application can be structurally indistinguishable. Exemplarily, in the case where the transistor is a P-type transistor, the first pole / first end of the transistor is the source, and the second pole / second end is the drain; exemplarily, in the case where the transistor is an N-type transistor, the first pole / first end of the transistor is the drain, and the second pole / second end is the source.

[0045] In the circuit structure provided in the embodiments of the present application, the first node, the second node and other nodes do not represent actual existing components, but represent the junction points of related couplings in the circuit diagram, that is, these nodes are nodes formed by the equivalent junction points of related couplings in the circuit diagram.

[0046] At present, low-dropout linear regulators are a new generation of integrated circuit regulators, which are widely used in smart phones, tablet computers, Bluetooth headsets, automobiles, wireless communications, embedded systems and other application scenarios. Figure 1 , Figure 1A schematic diagram of a low-voltage difference linear regulator in the related art is shown. The low-voltage difference linear regulator includes a power tube m0, a voltage-dividing resistor r1, a voltage-dividing resistor r2, a filter resistor r3, a filter capacitor c1 and an operational amplifier OP. The drain of the power tube m0 is connected to the input power supply voltage VIN. The filter resistor r3 and the filter capacitor c1 form a low-pass filter to filter the source output target voltage VOUT of the power tube m0. The series-connected voltage-dividing resistor r1 and the voltage-dividing resistor r2 output a feedback voltage VFB. The operational amplifier OP controls the gate voltage of the power tube according to the input reference voltage VREF and the feedback voltage VFB, so that the power tube m0, the voltage-dividing resistor r1 and the operational amplifier OP form a negative feedback loop, and finally ensure the stability of the target voltage VOUT.

[0047] In the related art, when an electronic device has one or more internal power sources (such as batteries) and / or is connected to one or more external power sources (such as power input from a TYPE-C interface), it is necessary to select one of the power sources for power supply to ensure that the electronic device works normally. Figure 2 , Figure 2 A power supply schematic diagram of an electronic device in the related art is shown, and the electronic device includes a battery module, a MUC microcontroller, a buck / boost circuit, a TYPE-C interface, a low-dropout linear regulator 1, a low-dropout linear regulator 2, a voltage selector, and a bandgap reference circuit.

[0048] Among them, the 20V voltage connected to the TYPE-C interface is converted into a 40V voltage by the buck / boost circuit to charge the battery module, and the voltage of the battery module is outputted as 5V for the power delivery system (PD) after buck / boost processing, and the low voltage difference linear regulator 1 can convert the 5V voltage outputted by the battery module into a 3.3V voltage according to the 3.3V reference voltage outputted by the bandgap reference source, and the low voltage difference linear regulator 2 can convert the 20V voltage outputted by the TYPE-C interface into a 3.3V voltage according to the 3.3V reference voltage outputted by the bandgap reference source, so as to provide a stable power supply voltage for the MCU microcontroller. Generally, when the battery module has power (for example, when the voltage outputted by the battery module is greater than or equal to 4.8V), the voltage selector selects the low voltage linear regulator 1 to output a 3.3V voltage; when the battery module has no power (for example, when the voltage outputted by the battery module is less than 4.8V), the voltage selector selects the low voltage linear regulator 2 to output a 3.3V voltage to ensure the normal power supply of the electronic device.

[0049] However, when switching power supplies, for example, when the voltage selector switches from the output of 3.3V voltage by the low-voltage dropout linear regulator 1 to the output of 3.3V voltage by the low-voltage dropout linear regulator 2, the current of the higher voltage power supply may flow back to the lower voltage power supply, which leads to the problem of circuit damage of the low-voltage dropout linear regulator due to the current backflow.

[0050] To this end, the present application provides a low voltage dropout linear regulator, a chip and an electronic device, which are described in detail below.

[0051] First, see Figure 3 , Figure 3 A schematic diagram of a low voltage difference linear regulator in an embodiment of the present application is shown, wherein the low voltage difference linear regulator includes a power tube M0, a voltage division sampling module 10, an error amplification module 20 and an anti-backflow module 30.

[0052] Specifically, the first end of the power tube M0 is connected to the power supply voltage Vin, the second end of the power tube M0 outputs the target voltage Vout, and the control end of the power tube M0 is controlled by the error amplification module 20, so as to change the conduction voltage of the power tube M0 and ensure the stability of the target voltage Vout. Exemplarily, the power supply voltage Vin can be provided by, but not limited to, a battery and / or an interface, such as a zinc battery, a nickel battery, a lead battery, a lithium battery, a manganese dioxide series battery or an air (oxygen) series battery, etc., and an interface such as a TYPE-C interface, a TYPE-B interface, a TYPE-A interface, a Micro USB interface, a Lightning interface, a USB A type interface, a USB B type interface, a circular interface, a 30-pin charging interface, a Combo socket, a Dock interface, an SDP interface, etc.

[0053] It should be noted that the power tube M0 in the present application can be a PMOS tube or an NMOS tube, and the source of the power tube M0 is one of the first end of the power tube M0 and the second end of the power tube M0. The present application does not make specific limitations. For the sake of convenience, the drawings of the relevant embodiments of the present application take the power tube M0 as a PMOS as an example for exemplary description. In the drawings of the relevant embodiments, the first end of the power tube M0 is the source of the PMOS tube, and the second end of the power tube M0 is the drain of the PMOS tube. It can be understood that when the power tube M0 is an NMOS tube, then the first end of the power tube M0 is the drain of the NMOS tube, and the second end of the power tube M0 is the source of the NMOS tube.

[0054] The voltage-dividing sampling module 10 is connected to the second end of the power tube M0, and is used to output a feedback voltage Vfb according to the target voltage Vout, so that the error amplification module 20 can perform negative feedback control on the power tube M0 through the feedback voltage Vfb. As an example, the voltage-dividing sampling module 10 may include a plurality of resistors connected in series, and the feedback voltage Vfb can be output between any two adjacent resistors; as another example, the voltage-dividing sampling module 10 may include a plurality of resistors connected in series and in parallel, and the feedback voltage Vfb is output at a node in the series resistors or the parallel resistors.

[0055] The input end of the error amplification module 20 is connected to the feedback voltage Vfb and the reference voltage Vref, and the output end of the error amplification module 20 is connected to the control end of the power tube M0, so that the error amplification module controls the magnitude of the target voltage Vout based on the voltage difference between the feedback voltage Vfb and the reference voltage Vref. For example, when the target voltage Vout increases, the feedback voltage Vfb increases accordingly, and the voltage difference between the feedback voltage Vfb and the reference voltage Vref decreases, then the error amplification module 20 can increase the voltage of the gate of the power tube M0, so that the on-resistance of the power tube M0 increases and the target voltage Vout is reduced, thereby realizing negative feedback control of the target voltage Vout; for another example, when the target voltage Vout decreases, the feedback voltage Vfb decreases accordingly, and the voltage difference between the feedback voltage Vfb and the reference voltage Vref increases, then the error amplification module 20 can reduce the voltage of the gate of the power tube M0, so that the on-resistance of the power tube M0 decreases and the target voltage Vout is increased, thereby realizing negative feedback control of the target voltage Vout.

[0056] Exemplarily, the error amplification module may include but is not limited to an operational amplifier OP or a differential amplifier circuit such as a DC-coupled differential amplifier circuit and a feedback differential amplifier circuit.

[0057] The backflow prevention module 30 is connected to the source of the power tube M0, for example Figure 3 As shown, the power tube M0 is a PMOS tube, the anti-backflow module 30 is connected to the first end of the power tube M0, and the anti-backflow module 30 is connected to the substrate of the power tube M0, so that when the target voltage Vout is greater than the power supply voltage Vin, the anti-backflow module 30 controls the substrate of the power tube M0 to be disconnected from the source of the power tube M0, so that the power tube M0 changes from the on state to the off state, thereby preventing the power tube M0 from experiencing current backflow.

[0058] As an example, see Figure 4 , Figure 4Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, the anti-backflow module 30 includes a PMOS tube MP0, the source of the PMOS tube MP0 is connected to the substrate of the power tube M0, the drain of the PMOS tube MP0 is connected to the first end of the power tube M0, and the gate of the PMOS tube is connected to the second end of the power tube M0. When the target voltage Vout is less than the power supply voltage Vin, the PMOS tube MP0 is in the on state, so the substrate and the source of the power tube M0 are connected and work normally; when the target voltage Vout is greater than the power supply voltage Vin, the PMOS tube MP0 is in the off state, so the substrate and the source of the power tube M0 are disconnected, so that the power tube M0 enters the off state to avoid the backflow current phenomenon of the power tube M0.

[0059] The present application connects the anti-backflow module 30 to the source of the power tube M0, and connects the anti-backflow module 30 to the substrate of the power tube M0. When the target voltage Vout is greater than the power supply voltage Vin, the anti-backflow module 30 can control the substrate of the power tube M0 to be disconnected from the source of the power tube M0. At this time, the substrate of the power tube M0 is equivalent to an empty connection, so that the power tube M0 changes from the on state to the off state. Therefore, it can be avoided that during the power switching process, the target voltage Vout is greater than the power supply voltage Vin, which causes the current to flow back to the power supply through the power tube M0 and thus damage the power tube M0.

[0060] In some embodiments of the present application, see Figure 5 , Figure 5 Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the anti-backflow module 30 is connected to the control end of the power tube M0, and the anti-backflow module 30 is connected to the output end of the error amplification module 20; when the target voltage Vout is greater than the power supply voltage Vin, the anti-backflow module 30 controls the disconnection between the control end of the power tube M0 and the output end of the error amplification module 20. That is to say, when the target voltage Vout is higher than the power supply voltage Vin, the anti-backflow module 30 can also make the gate of the power tube M0 empty, thereby avoiding the phenomenon that the error amplification module 20 continues to control the gate voltage of the power tube M0 when current backflow occurs.

[0061] Further, in some embodiments of the present application, see Figure 6 , Figure 6Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the anti-backflow module 30 is also connected to the second end of the power tube M0. When the target voltage Vout is greater than the power supply voltage Vin, the anti-backflow module 30 can also control the control end of the power tube M0 and the second end of the power tube M0 to be turned on. At this time, the gate voltage of the power tube M0 becomes the target voltage Vout with a higher voltage, so the power tube M0 can be quickly put into the cut-off state, which is conducive to better preventing the backflow current from flowing through the power tube M0.

[0062] It can be understood that the above embodiment takes the power tube M0 as a PMOS tube as an example to connect the gate of the PMOS tube to a target voltage Vout with a higher voltage. If the power tube M0 is an NMOS tube, the anti-backflow module 30 can control the gate of the NMOS tube to connect to a power supply voltage Vin with a lower voltage.

[0063] In some embodiments of the present application, see Figure 7 , Figure 7 Another schematic diagram of a low voltage difference linear regulator in an embodiment of the present application is shown, wherein the backflow prevention module 30 includes a comparison unit 31 and a first switch unit 32; the first input end of the comparison unit 31 is connected to the first end of the power tube M0 to access the power supply voltage Vin, and the second input end of the comparison unit 31 is connected to the second end of the power tube M0 to access the target voltage Vout; one end of the first switch unit 32 is connected to the substrate of the power tube M0, and the other end is connected to the source of the power tube M0, and the control end of the first switch unit 32 is connected to the output end of the comparison unit 31.

[0064] It should be noted that the comparison unit 31 can compare the power supply voltage Vin with the target voltage Vout, thereby outputting a control signal to control the first switch unit 32 to open or close. For example, when the power supply voltage Vin is greater than the target voltage Vout, the comparison unit 31 can output a low-level signal, thereby using the low-level signal to control the first switch unit 32 to close so that the power tube M0 works normally; conversely, when the power supply voltage Vin is less than the target voltage Vout, the comparison unit 31 can output a high-level signal, thereby using the high-level signal to control the first switch unit 32 to open so that the power tube M0 is turned off, so as to prevent the backflow current from flowing through the power tube M0.

[0065] In some embodiments of the present application, for example, for an embodiment in which the anti-backflow module 30 can control the disconnection between the control end of the power tube M0 and the output end of the error amplification module 20, see Figure 8 , Figure 8Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the backflow prevention module 30 also includes a second switch unit 33; one end of the second switch unit 33 is connected to the control end of the power tube M0, and the other end is connected to the output end of the error amplification module 20, and the control end of the second switch unit 33 is connected to the output end of the comparison unit 31.

[0066] It should be noted that, since the control end of the second switch unit 33 is connected to the output end of the comparison unit 31, the comparison unit 31 can also control the second switch unit 33 to be opened or closed. For example, when the power supply voltage Vin is greater than the target voltage Vout, the comparison unit 31 can output a low-level signal, thereby controlling the second switch unit 33 to be closed by using the low-level signal, thereby making the control end of the power tube M0 connected to the output end of the error amplification module 20 and working normally; conversely, when the power supply voltage Vin is less than the target voltage Vout, the comparison unit 31 can output a high-level signal, thereby controlling the second switch unit 33 to be opened by using the high-level signal, thereby making the control end of the power tube M0 disconnected from the output end of the error amplification module 20 to prevent the backflow current from flowing through the power tube M0.

[0067] In some embodiments of the present application, for example, the anti-backflow module 30 can control the control end of the power tube M0 to be connected to the second end of the power tube M0, see Fig. 9 , Fig. 9 Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the anti-backflow module 30 also includes a third switch unit 34; one end of the third switch unit 34 is connected to the control end of the power tube M0, and the other end is connected to the second end of the power tube M0.

[0068] It should be noted that when the target voltage Vout is less than the power supply voltage Vin, the third switch unit 34 is in the cut-off state, so the control end of the power tube M0 is not connected to the target voltage Vout and can work normally. When the target voltage Vout is greater than the power supply voltage Vin, the third switch unit 34 is in the on state, combined with the embodiment in which the second switch unit 33 is disconnected at this time, this is equivalent to changing the gate voltage of the power tube M0 to the target voltage Vout with a higher voltage, so the power tube M0 can be quickly put into the cut-off state, which is conducive to better preventing the backflow current from flowing through the power tube M0.

[0069] As an exemplary embodiment of the comparison unit 31, see Fig.10 , Fig.10Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, the comparison unit 31 includes a first high potential conduction transistor MP1 and a first low potential conduction transistor MN1; the first end of the first high potential conduction transistor MP1 is connected to the target voltage Vout, the second end of the first high potential conduction transistor MP1 is connected to the second end of the first low potential conduction transistor MN1, and the control end of the first high potential conduction transistor MP1 is connected to the power supply voltage Vin; the second end of the first low potential conduction transistor MN1 is connected to the ground end, the first end of the first low potential conduction transistor MN1 is connected to the ground end, and the control end of the first low potential conduction transistor MN1 is connected to the power supply voltage Vin; the control end of the first switch unit 32 is connected to the first node m1 between the first high potential conduction transistor MP1 and the first low potential conduction transistor MN1.

[0070] Specifically, when the target voltage Vout is greater than the power supply voltage Vin, the first high potential conduction transistor MP1 is turned on, and the first node m1 can output a high level signal. Therefore, the high level signal can be used to control the first switch unit 32 and the second switch unit 33 to be disconnected. At this time, the gate and substrate of the power tube M0 are unconnected, so that the power tube M0 enters the cut-off state to prevent the current backflow phenomenon; conversely, when the target voltage Vout is lower than the power supply voltage Vin, the first high potential conduction transistor MP1 is in the cut-off state, and the first node m1 can output a low level signal. Therefore, the low level signal can be used to control the first switch unit 32 and the second switch unit 33 to be turned on, so that the power tube M0 and the low voltage difference linear regulator work normally.

[0071] Those skilled in the art will appreciate that the comparison unit 31 may also directly use a comparator to compare the target voltage Vout with the power supply voltage Vin, and after the comparator completes the comparison process, it may output a control signal to control the first switch unit 32 and the second switch unit 33 .

[0072] In some embodiments of the present application, for example, for an embodiment in which the anti-backflow module 30 includes a first switch unit 32, see Fig.11 , Fig.11Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the first switch unit 32 includes a first transistor M1; the first end of the first transistor M1 is connected to the substrate of the power tube M0, the second end of the first transistor M1 is connected to the source of the power tube M0, and the control end of the first transistor M1 is connected to the output end of the comparison unit 31. Specifically, taking the first transistor M1 as a PMOS tube as an example, when the target voltage Vout is greater than the power supply voltage Vin, the first comparison unit 31 outputs a high level signal, so the first transistor M1 is turned off, so that the substrate and the source of the power tube M0 are disconnected; conversely, when the target voltage Vout is less than the power supply voltage Vin, the first comparison unit 31 outputs a low level signal, so the first transistor M1 is turned on, so that the substrate and the source of the power tube M0 are turned on and work normally.

[0073] In other embodiments of the present application, see Fig.12 , Fig.12 Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, the first switch unit 32 may also include a second transistor M2; the first end of the second transistor M2 is connected to the substrate of the power tube M0, the second end of the second transistor M2 is connected to the source of the power tube M0, the control end of the second transistor M2 is connected to the target voltage Vout, so the second transistor M2 is controlled by the target voltage Vout, when the target voltage Vout is greater than the power supply voltage Vin, the second transistor M2 can be turned off, and the substrate and the source of the power tube M0 will be disconnected only after the first transistor M1 and the second transistor M2 are turned off at the same time.

[0074] It should be noted that, due to the fluctuation of the target voltage Vout, the target voltage Vout may be greater than the power supply voltage Vin in a short time, causing the substrate and the source of the power tube M0 to be disconnected and turned on from time to time, which is not conducive to the low voltage difference linear regulator outputting a stable target voltage Vout; in the above embodiment, since the first transistor M1 is controlled by the comparison unit 31, and the second transistor M2 is controlled by the target voltage Vout, then when the target voltage Vout is greater than the power supply voltage Vin in a short time, the second transistor M2 will enter the cut-off state before the first transistor M1, and after the first transistor M1 is switched to the cut-off state, the second transistor M2 is switched to the on state, thereby avoiding the phenomenon that the substrate and the source of the power tube M0 are disconnected and turned on from time to time due to the fluctuation of the target voltage Vout.

[0075] It should be pointed out that, unless otherwise specified, the transistors in the present application (for example, the first transistor M1, the second transistor M2, the third transistor M3, etc.) can be low-potential conduction transistors, such as PMOS tubes, NPN transistors, IGBT tubes with P channels, etc., or can be high-potential conduction transistors, such as NMOS tubes, PNP transistors, IGBT tubes with N channels, etc., and those skilled in the art can make a selection according to actual needs, and this application does not make any specific limitations.

[0076] In some embodiments of the present application, for example, for an embodiment in which the backflow prevention module 30 includes a second switch unit 33, see Fig.13 , Fig.13 Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application is shown, wherein the second switch unit 33 includes a third transistor M3, a first inverter INV1 and a fourth transistor M4; the first end of the third transistor M3 is connected to the control end of the power tube M0, the second end of the third transistor M3 is connected to the output end of the error amplification module 20, and the control end of the third transistor M3 is connected to the output end of the comparison unit 31; the input end of the first inverter INV1 is connected to the output end of the comparison unit 31, and the output end of the first inverter INV1 is connected to the control end of the fourth transistor M4; the first end of the fourth transistor M4 is connected to the control end of the power tube M0, and the second end of the fourth transistor M4 is connected to the output end of the error amplification module 20.

[0077] It should be noted that, since the third transistor M3 is directly controlled by the signal at the output end of the comparison unit 31, and the fourth transistor M4 is controlled by the signal output by the inverter, and the inverter has a certain delay effect, the second switch unit 33 is similar to the first switch unit 32, and the third transistor M3 and the fourth transistor M4 in the second switch unit 33 are not synchronously turned off, but the third transistor M3 is turned off before the fourth transistor M4. Therefore, when the target voltage Vout is greater than the power supply voltage Vin in a short time, the third transistor M3 will be turned off before the fourth transistor M4, and after the fourth transistor M4 is turned off, the third transistor M3 is switched to the on state, thereby avoiding the phenomenon that the control end of the power tube M0 and the output end of the error amplifier module 20 are disconnected and turned on from time to time due to the fluctuation of the target voltage Vout.

[0078] It can be understood that the first switch unit 32 and the second switch unit 33 can also be provided with a greater number of switches that enter the cut-off state asynchronously, for example, see Fig.14 , Fig.14A schematic diagram of the second switch unit 33 in an embodiment of the present application is shown, wherein the second switch unit 33 also includes a sixth transistor M6, a first end of the sixth transistor M6 is connected to the control end of the power tube M0, a second end of the sixth transistor M6 is connected to the output end of the error amplification module 20, and the control end of the sixth transistor M6 is connected to the target voltage Vout. Then, when the target voltage Vout is greater than the power supply voltage Vin, the sixth transistor M6 will enter the cut-off state before the third transistor M3 and the fourth transistor M4.

[0079] In some embodiments of the present application, for example, for an embodiment in which the backflow prevention module 30 further includes a third switch unit 34, see Fig.15 , Fig.15 Another schematic diagram of the low voltage difference linear regulator in the embodiment of the present application, wherein the third switch unit 34 includes a fifth transistor M5; the first end of the fifth transistor M5 is connected to the second end of the power tube M0 to access the target voltage Vout, the second end of the fifth transistor M5 is connected to the control end of the power tube M0, and the control end of the fifth transistor M5 is connected to the power supply voltage Vin. When the target voltage Vout is greater than the power supply voltage Vin, the fifth transistor M5 will be turned on, so that the control end of the power tube M0 is connected to its second end, which is equivalent to changing the gate voltage of the power tube M0 to a higher voltage target voltage Vout, so that the power tube M0 can be quickly put into a cut-off state, which is conducive to better preventing backflow current from flowing through the power tube M0.

[0080] In some embodiments of the present application, see Fig.15 The voltage division sampling module 10 includes a first resistor R1 and a second resistor R2, and the error amplification module 20 includes an operational amplifier OP; one end of the first resistor R1 is connected to the second end of the power tube M0, and the other end is connected to the second resistor R2, and the second resistor R2 is connected to the ground end. The non-inverting input end of the operational amplifier OP is connected to the reference voltage Vref, and the inverting input end of the operational amplifier OP is connected to the second node m2 between the first resistor R1 and the second resistor R2, so that the operational amplifier OP controls the on-resistance of the power tube M0 according to the feedback voltage Vfb negatively fed back by the second node m2.

[0081] It is worth noting that the above content is intended to clearly illustrate the implementation verification process of the present application. Those skilled in the art can modify and adjust the implementation methods of the present application under the guidance of the present application. For example, refer to Fig.16 , Fig.16A schematic diagram of the comparison unit 31 in an embodiment of the present application is shown. The comparison unit 31 can also connect multiple transistors MN2 and MN3 in series at the first end of the first low-potential turn-on transistor MN1, and short-circuit the drains and gates of the transistors MN2 and MN3 to form a clamping transistor to ensure the potential of the output signal of the first node m1.

[0082] The embodiment of the present application also provides a chip, which includes the above-mentioned low-dropout linear regulator. The chip (Integrated Circuit, IC) is also called a chip, and the chip can be but is not limited to a SOC (System on Chip, chip-level system) chip, a SIP (system in package, system-level packaging) chip. Since the chip in the embodiment of the present application has the low-dropout linear regulator described in the above embodiment, it has all the beneficial effects of the low-dropout linear regulator in the above embodiment, which will not be repeated here.

[0083] The embodiment of the present application also provides an electronic device, which includes a device body and a chip as described above provided in the device body. The electronic device may be, but is not limited to, a weight scale, a body fat scale, a nutrition scale, an infrared electronic thermometer, a pulse oximeter, a human body composition analyzer, a mobile power supply, a wireless charger, a fast charger, a car charger, an adapter, a display, a USB (Universal Serial Bus) docking station, a stylus, a true wireless headset, a car central control screen, a car, a smart wearable device, a mobile terminal, and a smart home device. Smart wearable devices include, but are not limited to, smart watches, smart bracelets, and cervical massagers. Mobile terminals include, but are not limited to, smart phones, laptops, tablet computers, and POS (point of sales terminal). Smart home devices include, but are not limited to, smart sockets, smart rice cookers, smart sweepers, and smart lights.

[0084] The above are only preferred embodiments of the present application, and are not intended to limit the present application in any form. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A low voltage dropout linear regulator, characterized in that: include: A power tube, a first end of which is connected to a power supply voltage, and a second end of which outputs a target voltage; A voltage division sampling module, the voltage division sampling module is connected to the second end of the power tube to output a feedback voltage according to the target voltage; An error amplification module, wherein an input end of the error amplification module is connected to the feedback voltage and the reference voltage, and an output end of the error amplification module is connected to the control end of the power tube, so as to control the magnitude of the target voltage based on the voltage difference between the feedback voltage and the reference voltage; an anti-backflow module, wherein the anti-backflow module is connected to the source of the power tube, and the anti-backflow module is connected to the substrate of the power tube, and the source of the power tube is one of the first end of the power tube and the second end of the power tube; When the target voltage is greater than the power supply voltage, the anti-backflow module controls the substrate of the power tube to be disconnected from the source of the power tube.

2. The low voltage dropout linear regulator according to claim 1, characterized in that: The backflow prevention module is connected to the control end of the power tube, and the backflow prevention module is connected to the output end of the error amplification module; When the target voltage is greater than the power supply voltage, the anti-backflow module controls the control end of the power tube to be disconnected from the output end of the error amplification module.

3. The low voltage dropout linear regulator according to claim 2, characterized in that: The backflow prevention module is connected to the second end of the power tube; When the target voltage is greater than the power supply voltage, the backflow prevention module controls the control end of the power tube to be connected with the second end of the power tube.

4. The low dropout linear regulator according to claim 1, characterized in that: The backflow prevention module includes a comparison unit and a first switch unit; The first input end of the comparison unit is connected to the first end of the power tube to access the power supply voltage, and the second input end of the comparison unit is connected to the second end of the power tube to access the target voltage; One end of the first switch unit is connected to the substrate of the power tube, and the other end is connected to the source of the power tube, and the control end of the first switch unit is connected to the output end of the comparison unit.

5. The low voltage dropout linear regulator according to claim 4, characterized in that: The backflow prevention module also includes a second switch unit; One end of the second switch unit is connected to the control end of the power tube, and the other end is connected to the output end of the error amplification module, and the control end of the second switch unit is connected to the output end of the comparison unit.

6. The low voltage dropout linear regulator according to claim 4, characterized in that: The backflow prevention module also includes a third switch unit; One end of the third switch unit is connected to the control end of the power tube, and the other end is connected to the second end of the power tube; Wherein, when the target voltage is greater than the power supply voltage, the third switch unit is in an on state.

7. The low voltage dropout linear regulator according to claim 4, characterized in that: The comparison unit includes a first high potential conduction transistor and a first low potential conduction transistor; The first end of the first high potential conduction transistor is connected to the target voltage, the second end of the first high potential conduction transistor is connected to the second end of the first low potential conduction transistor, and the control end of the first high potential conduction transistor is connected to the power supply voltage; The first end of the first low potential conduction transistor is connected to the ground end, and the control end of the first low potential conduction transistor is connected to the power supply voltage; Wherein, the control end of the first switch unit is connected to a first node between the first high potential conduction transistor and the first low potential conduction transistor.

8. The low voltage dropout linear regulator according to claim 4, characterized in that: The first switch unit includes a first transistor; The first end of the first transistor is connected to the substrate of the power tube, the second end of the first transistor is connected to the source of the power tube, and the control end of the first transistor is connected to the output end of the comparison unit.

9. The low dropout linear regulator according to claim 8, characterized in that: The first switch unit further includes a second transistor; The first end of the second transistor is connected to the substrate of the power tube, the second end of the second transistor is connected to the source of the power tube, and the control end of the second transistor is connected to the target voltage.

10. The low voltage dropout linear regulator according to claim 5, characterized in that: The second switch unit includes a third transistor, a first inverter and a fourth transistor; The first end of the third transistor is connected to the control end of the power tube, the second end of the third transistor is connected to the output end of the error amplification module, and the control end of the third transistor is connected to the output end of the comparison unit; The input end of the first inverter is connected to the output end of the comparison unit, and the output end of the first inverter is connected to the control end of the fourth transistor; The first end of the fourth transistor is connected to the control end of the power tube, and the second end of the fourth transistor is connected to the output end of the error amplification module.

11. The low dropout linear regulator according to claim 6, characterized in that: The third switch unit includes a fifth transistor; The first end of the fifth transistor is connected to the second end of the power tube to access the target voltage, the second end of the fifth transistor is connected to the control end of the power tube, and the control end of the fifth transistor is connected to the power supply voltage.

12. A chip, characterized in that: The invention comprises a low voltage drop linear regulator as claimed in any one of claims 1 to 11.

13. An electronic device, characterized in that: Comprising the chip as claimed in claim 12.

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