Overcurrent detection circuit of low voltage dropout regulator and low voltage dropout stabilization system

Abstract

The present invention provides an overcurrent detection circuit of a low-dropout voltage regulator and a low-dropout voltage stabilization system, wherein the overcurrent detection circuit of the low-dropout voltage regulator includes: two charge storage circuits, a control module and a counting circuit. The control module controls and provides charging paths for the two charge storage circuits, so that the two charge storage circuits are charged by a reference current and a sensing current respectively, and the sensing current is generated by the output current of the low-dropout voltage regulator. The counting circuit obtains the voltage of the charge storage circuit charged by the sensing current, counts accordingly, and outputs an overcurrent detection signal when the count reaches a specific value. In the case where the output current is an overcurrent, the counting circuit will first count to a specific value before the charge storage circuit charged by the reference current is charged to a specific voltage.

Description

Technical Field

[0001] The present invention relates to an overcurrent detection circuit of a low voltage dropout regulator, and in particular to an overcurrent detection circuit without using an operational amplifier and a low voltage dropout voltage stabilizing system using the overcurrent detection circuit. Background Art

[0002] In order to ensure that its load transient regulation, line transient regulation and stability under various loads meet certain requirements, a low drop-out regulator (LDO) performs overcurrent detection to determine whether the output current is too large, and adjusts and compensates the low drop-out regulator in response to the excessive output current.

[0003] The output current sensing method of the known low dropout regulator is to stably copy the current flowing through the power device of the low dropout regulator through an operational amplifier, and then convert the current into a voltage through a resistor to generate a detection voltage. Because overcurrent detection is required, it is necessary to use a voltage comparator to determine whether the sensing current generated by the output current exceeds a preset current, or to use a current comparator to make the determination.

[0004] The above approach requires adding an operational amplifier and comparator to the original low-dropout regulator circuit, which increases the area and quiescent current requirements of the overall circuit, and also requires additional consideration of the stability of the current sensing path, which results in many difficulties and limitations in the design. Furthermore, the gain and input offset voltage of the comparator will affect the important parameters of the overcurrent detection level, so there are still more difficulties in the design. Summary of the invention

[0005] The object of the present invention is to provide an overcurrent detection circuit of a low voltage dropout regulator and a low voltage dropout voltage stabilization system using the same, which can realize overcurrent detection of the low voltage dropout regulator at a lower cost and in a simpler way.

[0006] An embodiment of the present invention provides an overcurrent detection circuit of a low-dropout voltage regulator, comprising a first charge storage circuit, a second charge storage circuit, a counting circuit and a control module. The first charge storage circuit is used to be charged by a reference current, wherein the first voltage of the first charge storage circuit is charged from the first initial voltage to the first specific voltage in a first specific time. The second charge storage circuit is used to be charged by a sensing current, wherein the second voltage of the second charge storage circuit is charged from the second initial voltage to the second specific voltage in a second specific time, the second specific time is less than the first specific time, and the measured current is generated by the output current of the low-dropout voltage regulator. The counting circuit is electrically connected to the second charge storage circuit, receives the second voltage, counts according to the second voltage, and outputs an overcurrent detection signal when the count reaches a specific value. The control module is electrically connected to the first charge storage circuit, the second charge storage circuit and the counting circuit, and is used to control and provide a charging path of the first charge storage circuit and a charging path of the second charge storage circuit. When the output current is an overcurrent, the counting circuit first counts to a specific value before the first voltage is charged to a first specific voltage; and when the output current is not an overcurrent, the first voltage is first charged to the first specific voltage before the counting circuit counts to a specific value.

[0007] An embodiment of the present invention further provides a low voltage dropout voltage regulation system, which includes a low voltage dropout voltage regulator and an overcurrent detection circuit of the low voltage dropout voltage regulator, wherein the overcurrent detection circuit of the low voltage dropout voltage regulator is electrically connected to the low voltage dropout voltage regulator.

[0008] In summary, compared with the prior art, the overcurrent detection circuit of the low dropout regulator of the present invention is a technical solution for realizing overcurrent detection without using an operational amplifier and a comparator, and has the advantages of low design complexity, low power consumption, low circuit area and low quiescent current.

[0009] In order to further understand the technology, means and effects of the present invention, reference may be made to the following detailed description and accompanying drawings, so that the purpose, features and concepts of the present invention can be thoroughly and specifically understood. However, the following detailed description and accompanying drawings are only used for reference and explanation of the implementation of the present invention, and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are provided to enable those skilled in the art to further understand the present invention and are incorporated in and constitute a part of the specification of the present invention. The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description of the present invention are used to explain the principles of the present invention.

[0011] Figure 1 is a block diagram of an overcurrent detection circuit of a low voltage dropout regulator according to a first embodiment of the present invention;

[0012] Figure 2 is a circuit diagram of an overcurrent detection circuit of a low voltage dropout regulator according to a second embodiment of the present invention;

[0013] Figure 3 It is a block diagram of a low voltage dropout regulator system using the overcurrent detection circuit of the low voltage dropout regulator according to the first or second embodiment of the present invention. DETAILED DESCRIPTION

[0014] Reference will now be made in detail to exemplary embodiments of the present invention, which are illustrated in the accompanying drawings. Where possible, the same component symbols are used in the drawings and the specification to refer to the same or similar components. In addition, the exemplary embodiments are only one way of implementing the design concept of the present invention, and the following multiple exemplary embodiments are not intended to limit the present invention.

[0015] The embodiment of the present invention mainly provides an overcurrent detection circuit of a low-dropout voltage regulator, which is used to determine whether the output current of the low-dropout voltage regulator is an overcurrent. The overcurrent detection circuit of the low-dropout voltage regulator of the present invention is designed with two charge storage circuits, a control module and a counting circuit. The control module controls and provides the charging paths of the two charge storage circuits, so that the two charge storage circuits are charged by a reference current and a sensing current respectively, wherein the sensing current is generated by the output current of the low-dropout voltage regulator. The counting circuit obtains the voltage of the charge storage circuit charged by the sensing current, and counts accordingly, and outputs an overcurrent detection signal when the count reaches a specific value. In the case where the output current is an overcurrent, the counting circuit will count to a specific value before the charge storage circuit charged by the reference current is charged to a specific voltage; and in the case where the output current is not an overcurrent, the charge storage circuit charged by the reference current will be charged to a specific voltage before the counting circuit counts to a specific value. Compared with the prior art, the overcurrent detection circuit of the low-dropout voltage regulator of the present invention does not need to use an operational amplifier and a comparator, thereby reducing the circuit area and reducing the complexity of the circuit design.

[0016] Next, please refer to Figure 1 , Figure 1 1 is a block diagram of an overcurrent detection circuit of a low voltage dropout regulator according to a first embodiment of the present invention. The overcurrent detection circuit 1 of the low voltage dropout regulator includes charge storage circuits 11, 14, control logic circuits 12, 15, charge and discharge path providing units 13, 17 and a counting circuit 16. The charge and discharge path providing unit 17 is electrically connected to the charge storage circuit 11 and the control logic circuit 12. The control logic circuit 12 is electrically connected to the charge storage circuit 11 through the charge and discharge path providing unit 17. The charge and discharge path providing unit 13 is electrically connected to the control logic circuit 12. The charge storage circuit 14 is electrically connected to the charge and discharge path providing unit 13. The control logic circuit 15 is electrically connected to the charge storage circuit 14, the charge and discharge path providing unit 13 and the control logic circuit 12.

[0017] The charge storage circuit 11 is used to be charged by a reference current Iref, wherein the voltage of the charge storage circuit 11 needs a first specific time to be charged from a first initial voltage to a first specific voltage. The charge-discharge path providing unit is controlled by an over-current detection disable signal ENB and a time arrival signal T_OUT to determine whether to provide a charging path for the reference current Iref to charge the charge storage circuit 11, wherein the over-current detection disable signal ENB is used to disable the over-current detection circuit 1 of the low-dropout regulator (that is, the inverted signal of the over-current detection enable signal), and the time arrival signal T_OUT is used to indicate that the voltage of the charge storage circuit 11 is charged to the first specific voltage.

[0018] The control logic circuit 12 generates a first charge-discharge path control signal to the charge-discharge path providing unit 13 and the control logic circuit 15 according to the voltage of the charge storage circuit 11 and the overcurrent detection signal D_OUT. The charge-discharge path providing unit 13 is used to receive the first charge-discharge path control signal generated by the control logic circuit 12 and the second charge-discharge path control signal generated by the control logic circuit 15 and the sensing current Isen, wherein the sensing current Isen is generated by the output current of the low-dropout regulator. The charge-discharge path providing unit 13 is controlled by the first charge-discharge path control signal and the second charge-discharge path control signal to determine whether to provide a charging path to the sensing current Isen to charge the charge storage circuit 14, and the voltage of the charge storage circuit 14 needs a second specific time to charge from the second initial voltage to the second specific voltage, wherein the second specific time is less than the first specific time. The control logic circuit 15 generates a second charge-discharge path control signal according to the voltage of the charge storage circuit 14 and the first charge-discharge path control signal.

[0019] Through the control logic circuit 15 controlling the charge-discharge path providing unit 13, the voltage of the charge storage circuit 14 is charged from the second initial voltage to the second specific voltage, and then discharged, and then charged again when the charge-discharge path providing unit 13 provides a charging path next time. The counting circuit 16 outputs an over-current detection signal D_OUT according to the voltage of the charge storage circuit 14 and when the count reaches a specific value, the count value of the counting circuit 16 increases by 1 when the voltage of the charge storage circuit 14 is the second specific voltage.

[0020] Thus, through the above-mentioned structure, when the output current is an overcurrent, before the voltage of the charge storage circuit 11 is charged to the first specific voltage, the counting circuit 16 first counts to a specific value; and when the output current is not an overcurrent, before the counting circuit 16 counts to the specific value, the voltage of the charge storage circuit 11 is first charged to the first specific voltage. Therefore, the technical solution of overcurrent detection can be implemented without using an operational amplifier and a comparator.

[0021] Please refer to Figure 1 and Figure 2 , Figure 2 is a circuit diagram of an overcurrent detection circuit of a low voltage dropout regulator according to a second embodiment of the present invention, which is different from Figure 1 In the first embodiment, the overcurrent detection circuit 1' of the low dropout regulator further includes pulse shaping circuits 18 and 19. The pulse shaping circuit 18 is electrically connected between the charge and discharge path providing unit 17 and the control logic circuit 12, and the pulse shaping circuit 19 is electrically connected between the charge storage circuit 14 and the counting circuit 16. The pulse shaping circuit 18 may include a buffer BUF1, and the pulse shaping circuit 19 may include a buffer BUF2, and the present invention is not limited thereto.

[0022] In the second embodiment, the charge storage circuit 11 includes a capacitor C1, the charge storage circuit 14 includes a capacitor C2, the control logic circuit 12 includes an OR gate OR2, the counting circuit 16 includes a counter CNT1, and the control logic circuit 15 includes an OR gate OR3. Because the second specific time must be less than the first specific time, the capacitance of the capacitor C2 is designed to be K times the capacitance of the capacitor C1, where K is a number greater than 1. In addition, the charge-discharge path providing unit 17 includes an OR gate OR1, a P-type transistor MP1 and an N-type transistor MN1, and the charge-discharge path providing unit 13 includes a P-type transistor MP2 and an N-type transistor MN2.

[0023] The OR gate OR1 is used to receive the over-current detection disable signal ENB and the time arrival signal T_OUT, and generate a first logic operation signal, wherein the first logic operation signal is the result of a logic OR operation of the over-current detection disable signal ENB and the time arrival signal T_OUT. The gate of the P-type transistor MP1 is electrically connected to the gate of the N-type transistor MN1, and is used to receive the first logic operation signal. The source of the P-type transistor MP1 receives the reference current Iref, the source of the N-type transistor MN1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is electrically connected to the ground voltage or the low voltage, and the drain of the P-type transistor MP1 is electrically connected to the drain of the N-type transistor MN1 and the buffer BUF1.

[0024] With such a structure, when current detection is enabled and the voltage at one end of the capacitor C1 is not charged to the first specific voltage, the capacitor C1 will be charged by the reference current Iref. Figure 2The output signal of the buffer BUF1 is plotted, and the time for the voltage at one end of the capacitor C1 to charge from the first initial voltage to the first specific voltage is the first specific time T1, wherein the first initial voltage is related to the voltage at the other end of the capacitor C1, and the first specific voltage is the threshold voltage that can make the output signal of the OR gate OR2 transition. Once one end of the capacitor C1 is charged to the first specific voltage, the capacitor C1 is not provided with a charging path and is discharged.

[0025] The OR gate OR2 performs a logic OR operation on the overcurrent detection signal D_OUT and the output signal of the buffer BUF1 to generate a first charge and discharge path control signal. The OR gate OR3 performs a logic OR operation on the output signal of the buffer BUF2 and the first charge and discharge path control signal to generate a second charge and discharge path control signal. The source of the P-type transistor MP2 receives the sensing current Isen, the gate of the P-type transistor MP2 receives the first charge and discharge path control signal, the drain of the P-type transistor MP2 and the drain of the N-type transistor MN1 are electrically connected to one end of the capacitor C2, the other end of the capacitor C2 is electrically connected to the ground voltage or the low voltage, and the gate of the N-type transistor MN2 receives the second charge and discharge path control signal.

[0026] Through such a structure, when overcurrent detection is enabled and the voltage at one end of capacitor C1 is not charged to the first specific voltage, the voltage at one end of capacitor C2 will be discharged after being charged from the second initial voltage to the second specific voltage, and then, after being discharged, it will be charged from the second initial voltage to the second specific voltage again, so that counter CNT1 will count continuously. Whether overcurrent occurs can be determined by whether counter CNT1 counts to a specific value within the first specific time T1. If overcurrent occurs, counter CNT1 is reset after the overcurrent detection signal D_OUT is output. If no overcurrent occurs, counter CNT1 is reset after the voltage at one end of capacitor C1 is charged to the first specific voltage (i.e., reaching the first specific time T1).

[0027] Figure 2 The output signal of the buffer BUF2 and the voltage at one end of the capacitor C2 are plotted. The time for the voltage at one end of the capacitor C2 to charge from the second initial voltage to the second specific voltage is the second specific time T2, wherein the second initial voltage is related to the voltage at the other end of the capacitor C2, and the second specific voltage is the threshold voltage that can make the counter CNT1 count and the output signal of the OR gate OR3 transition. In addition, the voltage at one end of the capacitor C2 has a sawtooth wave, and after passing through the buffer BUF2, it becomes a pulse square wave.

[0028] If the sensing current Isen is much larger than the reference current Iref, the counter CNT1 will count to a specific value before the first specific time T1 arrives, and an overcurrent detection signal D_OUT is generated. Through the capacitance formula C=Q / V, it can be calculated that C2=Q2 / V2=K*C1=K*Q1 / V1. Assuming that the threshold voltages of the transitions are the same (i.e., the first specific voltage is equal to the second specific voltage), Q2=K*Q1 can be obtained, that is, Isen*T2=K*Iref*T1. When the first specific time T1 is exactly equal to DF*T2 (DF is the specific value of the counter CNT1), Isen*T2=K*Iref*DF*T2, Isen=K*DF*Iref can be obtained, and the sensing current Isen is M times the output current Iload, i.e., Isen=M*Iload, and finally Iload=M*K*DF*Iref can be obtained. In this way, the magnitude of the output current Iload being judged as an overcurrent can be changed by changing the specific value DF of the counter CNT1.

[0029] Continue to refer to Figure 2 , Figure 2 The charge and discharge path providing unit 17 in the embodiment can be removed, so that the reference current Iref can directly charge the charge storage circuit 11, and the control logic circuit 125 is directly electrically connected to the charge storage circuit 11. At this time, it can be designed that the reference current Iref is provided only when the overcurrent detection circuit 1 of the low-dropout regulator is enabled and the time arrival signal T_OUT is not generated. In addition, the control logic circuit 15 can be implemented using a buffer instead. At this time, the control logic circuit 15 will no longer be electrically connected to the control logic circuit 12, and only generates a second charge and discharge path control signal to the charge and discharge path providing unit 13 based on the voltage of the charge storage circuit 14. At this time, it can be designed that the sensing current Isen is provided only when the overcurrent detection circuit 1 of the low-dropout regulator is enabled, the time arrival signal T_OUT is not generated, and the counting circuit 16 has not counted to a specific value. Furthermore, Figure 2 The pulse shaping circuits 18 and 19 are also not necessary components and can be directly removed. However, in a noisy environment, the pulse shaping circuits 18 and 19 can make the over-current detection circuit 1' of the low-dropout regulator have better noise resistance to improve the accuracy of the over-current detection signal D_OUT.

[0030] Please also refer to Figure 1 and Figure 2It can be known from the above embodiments that the overcurrent detection circuits 1 and 1' of the low voltage dropout regulator of the present invention are designed with two charge storage circuits 11, 14, a control module and a counting circuit 16. The control module controls and provides charging paths for the two charge storage circuits 11, 14 so that they are charged by the reference current Iref and the sensing current Isen respectively. The counting circuit 16 obtains the voltage of the charge storage circuit 14 charged by the sensing current Isen, and counts accordingly, and outputs an overcurrent detection signal D_OUT when the count reaches a specific value. In the case where the output current is an overcurrent, the counting circuit 16 will first count to a specific value before the charge storage circuit 11 charged by the reference current Iref is charged to a specific voltage; and in the case where the output current is not an overcurrent, the charge storage circuit 11 charged by the reference current Iref will first be charged to a specific voltage before the counting circuit 16 counts to a specific value. The above control module can be used Figure 1 The charge and discharge path is provided by the units 13, 17 and the control logic circuits 12, 15, and can also be used Figure 2 The charge and discharge path providing units 13, 17, control logic circuits 12, 15 and pulse shaping circuits 18, 19 are implemented, and the present invention is not limited to the implementation method of the control module.

[0031] Please refer to Figure 3 , Figure 3 It is a block diagram of a low-voltage dropout voltage stabilizing system using the overcurrent detection circuit of the low-voltage dropout voltage regulator of the first or second embodiment of the present invention. The low-voltage dropout voltage stabilizing system 2 includes a low-voltage dropout voltage regulator 21, a low-voltage load 22, a current sensing circuit 23, a reference current generating circuit 24, a compensation circuit 25, and an overcurrent detection circuit 1 (or 1') of the low-voltage dropout voltage regulator. The low-voltage dropout voltage regulator 21 is electrically connected to the low-voltage load 22, the current sensing circuit 23, the reference current generating circuit 24 and the compensation circuit 25, and is electrically connected to the overcurrent detection circuit 1 (or 1') of the low-voltage dropout voltage regulator through the current sensing circuit 23. The overcurrent detection circuit 1 (or 1') of the low-voltage dropout voltage regulator is electrically connected to the current sensing circuit 23, the reference current generating circuit 24 and the compensation circuit 25.

[0032] The low-voltage dropout regulator 21 receives a first system voltage AVDD and performs low-voltage dropout regulation on the first system voltage AVDD to generate a second system voltage VDD, and the second system voltage VDD is provided to a low-voltage load 22, a compensation circuit 25, a current sensing circuit 23 and a reference current generating circuit 24. The current sensing circuit 23 is used to sense the output current of the low-voltage dropout regulator 21 to generate a sensing current Isen, and the reference current generating circuit 24 is used to generate a reference current Iref. The overcurrent detection circuit 1 (or 1') of the low-voltage dropout regulator is used to obtain the sensing current Isen and the reference current Iref, and determine whether the output current of the low-voltage dropout regulator 21 is an overcurrent. If the output current of the low-voltage dropout regulator 21 is an overcurrent, an overcurrent detection signal D_OUT is output to the compensation circuit 25, so that the compensation circuit 25 adjusts the low-voltage dropout regulator 21 to avoid continuous overcurrent.

[0033] Accordingly, the present invention has the following advantages: (1) Different from the known circuit architecture, the overcurrent detection circuit of the low voltage dropout regulator of the present invention does not need to use comparators and operational amplifiers at all, thereby greatly reducing the design complexity of the trade-offs between circuit characteristics, area and quiescent current when designing the overcurrent detection circuit of the low voltage dropout regulator; (2) The overcurrent detection circuit of the low voltage dropout regulator of the present invention automatically turns off after completing the detection, and can complete the overcurrent detection without increasing the overall quiescent current of the low voltage dropout regulator. That is, when necessary, the overcurrent detection circuit of the low voltage dropout regulator can be turned on again, so it is suitable for application in low-power microcontrollers; and (3) The overcurrent detection circuit of the low voltage dropout regulator of the present invention is easy to design and change the level of overcurrent detection, and is also easy to perform process error correction.

[0034] It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light of them will be suggested to those skilled in the art and are to be included within the spirit and scope of the present application and the scope of the appended claims.

Claims

1. An overcurrent detection circuit for a low voltage dropout regulator, characterized in that: It includes a first charge storage circuit, a first control logic circuit, a first charge and discharge path providing unit, a second charge storage circuit, a second control logic circuit and a counting circuit; The first charge storage circuit is used to be charged by a reference current, and a first voltage of the first charge storage circuit is charged from a first initial voltage to a first specific voltage in a first specific time; The first control logic circuit is electrically connected to the first charge storage circuit and is used to generate a first charge and discharge path control signal according to the first voltage and the overcurrent detection signal; The first charge-discharge path providing unit is electrically connected to the first control logic circuit and is used to receive the first charge-discharge path control signal, the second charge-discharge path control signal and a sensing current, wherein the sensing current is generated by an output current of a low-dropout regulator; The second charge storage circuit is electrically connected to the first charge-discharge path providing unit, wherein the first charge-discharge path providing unit is controlled by the first charge-discharge path control signal and the second charge-discharge path control signal to determine whether to provide a charging path for the sensing current to charge the second charge storage circuit, and a second specific time is required for the second voltage of the second charge storage circuit to be charged from a second initial voltage to a second specific voltage, wherein the second specific time is less than the first specific time; The second control logic circuit is electrically connected to the second charge storage circuit and the first charge and discharge path providing unit, and generates the second charge and discharge path control signal according to the second voltage; as well as The counting circuit is electrically connected to the second charge storage circuit and the first control logic circuit, counts according to the second voltage, and outputs the overcurrent detection signal when the count reaches a specific value.

2. The overcurrent detection circuit of the low voltage dropout regulator according to claim 1, characterized in that: When the output current is an overcurrent, the counting circuit first counts to the specific value before the first voltage is charged to the first specific voltage; and when the output current is not an overcurrent, the first voltage is first charged to the first specific voltage before the counting circuit counts to the specific value.

3. The overcurrent detection circuit of the low voltage dropout regulator according to claim 1, characterized in that: The second control logic circuit is further electrically connected to the first control logic circuit, and the second control logic circuit generates the second charge-discharge path control signal according to the second voltage and the first charge-discharge path control signal.

4. The overcurrent detection circuit of the low voltage dropout regulator according to claim 3, characterized in that: It further includes a second charge and discharge path providing unit; The second charge and discharge path providing unit is electrically connected to the first charge storage circuit and the first control logic circuit, and is controlled by an overcurrent detection disable signal and a time arrival signal to determine whether to provide another charging path to the reference current to charge the first charge storage circuit, wherein the overcurrent detection disable signal is used to disable the overcurrent detection circuit of the low voltage dropout regulator, and the time arrival signal is used to indicate that the first voltage is charged to the first specific voltage.

5. The overcurrent detection circuit of the low voltage dropout regulator according to claim 4, characterized in that: further comprising a first pulse shaping circuit and a second pulse shaping circuit; The first pulse shaping circuit is electrically connected between the second charge and discharge path providing unit and the first control logic circuit; as well as The second pulse shaping circuit is electrically connected between the second charge storage circuit and the counting circuit; The first pulse shaping circuit includes a first buffer, and the second pulse shaping circuit includes a second buffer.

6. The overcurrent detection circuit of the low voltage dropout regulator according to claim 4, characterized in that: The second charge and discharge path providing unit includes a first OR gate, a first P-type transistor and a first N-type transistor; The first OR gate is used to receive the over-current detection disable signal and the time arrival signal, and generate a first logic operation signal; The gate of the first P-type transistor is electrically connected to the gate of the first N-type transistor and is used to receive the first logic operation signal, the source of the first P-type transistor receives the reference current, the source of the first N-type transistor is connected to the first charge storage circuit, and the drain of the first P-type transistor is electrically connected to the drain of the first N-type transistor.

7. The overcurrent detection circuit of the low voltage dropout regulator according to claim 4, characterized in that: The first charge and discharge path providing unit includes a second P-type transistor and a second N-type transistor; The source of the second P-type transistor receives the sensing current, the gate of the second P-type transistor receives the first charge and discharge path control signal, the drain of the second P-type transistor and the drain of the second N-type transistor are electrically connected to the second charge storage circuit, and the gate of the second N-type transistor receives the second charge and discharge path control signal.

8. The overcurrent detection circuit of the low voltage dropout regulator according to any one of claims 5 to 7, characterized in that: The first charge storage circuit includes a first capacitor, the second charge storage circuit includes a second capacitor, the first control logic circuit includes a second OR gate, and the second control logic circuit includes a third OR gate.

9. An overcurrent detection circuit for a low voltage dropout regulator, characterized in that: It includes a first charge storage circuit, a second charge storage circuit, a counting circuit and a control module; The first charge storage circuit is used to be charged by a reference current, and a first voltage of the first charge storage circuit is charged from a first initial voltage to a first specific voltage in a first specific time; The second charge storage circuit is used to be charged by the sensing current, and it takes a second specific time for the second voltage of the second charge storage circuit to be charged from the second initial voltage to the second specific voltage, the second specific time is less than the first specific time, and the sensing current is generated by the output current of the low dropout regulator; The counting circuit is electrically connected to the second charge storage circuit, receives the second voltage, counts according to the second voltage, and outputs an overcurrent detection signal when the count reaches a specific value; The control module is electrically connected to the first charge storage circuit, the second charge storage circuit and the counting circuit, and is used to control and provide a charging path of the first charge storage circuit and a charging path of the second charge storage circuit; Wherein, when the output current is an overcurrent, the counting circuit first counts to the specific value before the first voltage is charged to the first specific voltage; and when the output current is not the overcurrent, the first voltage is first charged to the first specific voltage before the counting circuit counts to the specific value.

10. A low voltage difference voltage stabilization system, characterized in that: The invention comprises an overcurrent detection circuit of a low voltage dropout regulator according to any one of claims 1 to 9 and the low voltage dropout regulator, wherein the overcurrent detection circuit of the low voltage dropout regulator is electrically connected to the low voltage dropout regulator.

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