A programmable over-current protection sampling control circuit applied to a load switch

Abstract

This invention belongs to the field of integrated circuits, and specifically relates to a programmable overcurrent protection sampling control circuit for power load switches. It includes a current sampling circuit, a current amplification circuit, and an overcurrent comparator. The current sampling circuit samples the output current through the on-resistance of the power MOSFET. The sampled signal is sent to the current amplification circuit and converted into a current at the ILIM terminal. An external resistor connected to the ILIM terminal converts the sampled current into a voltage, which is then compared with a set voltage threshold by the overcurrent comparator to achieve overcurrent protection. This invention integrates MOSFET on-resistance and power MOSFET mirror sampling, resulting in a simpler structure, higher sampling accuracy, and smaller temperature drift across the entire operating temperature range compared to traditional methods. Furthermore, the overcurrent protection threshold can be programmably adjusted via an external resistor, leading to a higher level of intelligence.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuits, and specifically relates to a programmable overcurrent protection sampling control circuit for load switches, used to realize current sampling and overcurrent protection functions. Background Technology

[0002] In the field of power management, overcurrent protection is a crucial technology that protects the output current and power of a power supply, effectively ensuring power supply safety. Overcurrent protection first requires sampling the output current. Common current sampling methods include power MOSFET on-resistance sampling, aluminum wire resistance sampling, and power MOSFET current mirror sampling. While power MOSFET on-resistance sampling is simple in structure as it doesn't require additional components or circuits, it suffers from significant temperature drift due to large variations in on-resistance with temperature. Aluminum wire resistance sampling and power MOSFET current mirror sampling are less accurate due to the uneven distribution of current flowing through the power MOSFET. Furthermore, the small resistance of the sampling resistor in these two methods results in a small voltage signal amplitude, making them susceptible to interference during high-power switching and prone to false triggering of the overcurrent protection comparator. Summary of the Invention

[0003] To improve the accuracy and temperature stability of current sampling, and to enable programmable adjustment of the overcurrent protection threshold through changes in external resistance, this invention provides a programmable overcurrent protection sampling control circuit for load switches. The circuit includes a current sampling circuit, a current amplification circuit, and an overcurrent comparator. The current sampling circuit samples the output current through the on-resistance of a power MOSFET. The sampled signal is then fed into the current amplification circuit and converted into a current at the ILIM terminal. An external resistor at the ILIM terminal converts the sampled current into a voltage, which is then compared with a set voltage threshold by the overcurrent comparator to achieve overcurrent protection.

[0004] Furthermore, the current sampling circuit is used to sample the current at the output current terminal. The current sampling circuit consists of two N-type MOSFETs, wherein:

[0005] The gates of the first N-type MOS transistor and the second N-type MOS transistor are connected to the drive signal terminal;

[0006] The drains of the first N-type MOSFET and the second N-type MOSFET are connected to the input power supply voltage terminal;

[0007] The source of the first N-type MOS transistor serves as the first output terminal of the current sampling circuit, and is connected to the output current terminal and the current amplification circuit.

[0008] The source of the second N-type MOS transistor serves as the second output terminal of the current sampling circuit, which is connected to the current amplification circuit.

[0009] Furthermore, the current amplifier circuit includes four N-type MOSFETs, seven P-type MOSFETs, and four resistors, wherein:

[0010] One end of the first resistor is connected to the source of the seventh P-type MOS transistor and the second output terminal of the current sampling circuit, and the other end is connected to the drain of the first P-type MOS transistor.

[0011] One end of the second resistor is connected to the first output terminal of the current sampling circuit, and the other end is connected to the drain of the second P-type MOS transistor.

[0012] The gates of the first P-type MOS transistor, the gates of the second P-type MOS transistor, the gates and drains of the fifth P-type MOS transistor, the gate of the sixth P-type MOS transistor, and the drain of the third N-type MOS transistor are connected together, and the source of the first P-type MOS transistor is connected to the source of the third P-type MOS transistor.

[0013] The source of the second P-type MOSFET is connected to the source of the fourth P-type MOSFET;

[0014] The gate and drain of the third P-type MOS transistor, the gate of the fourth P-type MOS transistor, and the source of the fifth P-type MOS transistor are connected together;

[0015] The drain of the fourth P-type MOSFET is connected to the source of the sixth P-type MOSFET;

[0016] The drain of the sixth P-type MOSFET is connected to one end of the third resistor, and the other end of the third resistor is connected to the gate of the seventh P-type MOSFET and the drain of the fourth N-type MOSFET.

[0017] The drain of the seventh P-type MOSFET, one end of the fourth resistor, and the current-limiting input terminal serve as the positive input of the overcurrent comparator.

[0018] The gates of the third and fourth N-type MOS transistors are connected to the second reference voltage, and the source of the third N-type MOS transistor is connected to the drain of the fifth N-type MOS transistor.

[0019] The source of the fourth N-type MOSFET is connected to the drain of the sixth N-type MOSFET;

[0020] The gates of the fifth and sixth N-type MOS transistors are connected to the first reference voltage, and the sources of the fifth and sixth N-type MOS transistors, as well as the other end of the fourth resistor, are connected to the ground terminal.

[0021] Furthermore, the on-resistance of the first N-type MOSFET is used to sample the output current to obtain a sampled voltage, which is then output from the first output terminal of the current sampling circuit. Through the mirroring effect of the first N-type MOSFET and the second N-type MOSFET, the current of the first N-type MOSFET is mirrored to the second N-type MOSFET proportionally.

[0022] Furthermore, the process of sampling the output current to obtain the sampling voltage by measuring the on-resistance of the first N-type MOSFET includes:

[0023]

[0024] in, V is the sampling voltage; IN I is the input power supply voltage. OUT For the output current, r O_NM1 This is the on-resistance of the first N-type MOSFET.

[0025] Furthermore, the sampling voltage is mirrored to the second output terminal of the current sampling circuit through the negative feedback of the current amplification circuit. The mirrored sampling voltage is converted into the current of the seventh P-type MOSFET through the on-resistance of the first N-type MOSFET, thus realizing the current mirroring of the first N-type MOSFET and the second N-type MOSFET.

[0026] Furthermore, the current of the seventh P-type MOSFET is expressed as follows:

[0027]

[0028] in, This refers to the current of the seventh P-type MOSFET; The sampled voltage is obtained by mirroring; V is the sampling voltage; IN I is the input power supply voltage. OUT For the output current, r O_NM2 This is the on-resistance of the second N-type MOSFET.

[0029] Furthermore, the negative input of the overcurrent comparator is the third reference voltage. When the voltage across the fourth resistor exceeds the current of the seventh P-type MOSFET, the overcurrent comparator reverses, indicating an overcurrent condition. The following conditions must be met during an overcurrent event:

[0030]

[0031] Among them, I OUT For the output current, r O_NM1 r is the on-resistance of the first N-type MOSFET. O_NM2 R4 is the on-resistance of the second N-type MOSFET, R4 is the resistance of the fourth resistor, and REF3 is the third reference voltage.

[0032] Furthermore, the fourth resistor is an externally programmable resistor, and the overcurrent threshold is adjusted by controlling the resistance value of the fourth resistor.

[0033] Compared to existing technologies, this invention utilizes a combination of MOSFET on-resistance and power MOSFET mirror sampling, amplifies the sampled signal, converts it into a current signal, and then uses an external programmable resistor to achieve programmable overcurrent protection sampling control. This effectively solves the problems of large temperature variations in power MOSFET on-resistance and small amplitude of the power MOSFET mirror current source sampling signal in conventional current sampling. Furthermore, the overcurrent protection threshold can be programmably adjusted by changing the external resistor. In summary, this invention integrates MOSFET on-resistance and power MOSFET mirror sampling, resulting in a simpler structure, higher sampling accuracy, smaller temperature drift across the entire operating temperature range, and programmable overcurrent protection threshold adjustment via an external resistor, demonstrating a higher level of intelligence. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a programmable overcurrent protection sampling control circuit applied to a load switch according to the present invention;

[0035] Figure 2 This is a schematic diagram showing the overcurrent comparator flipping when the fourth resistor has different values ​​in this invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] This invention discloses a programmable overcurrent protection sampling control circuit for load switches, comprising a current sampling circuit, a current amplification circuit, and an overcurrent comparator. The current sampling circuit samples the output current through the on-resistance of the power MOSFET. The sampled signal is sent to the current amplification circuit and converted into the current at the ILIM terminal. The sampled current is converted into a voltage through an external resistor connected to the ILIM terminal. The voltage is then compared with a set voltage threshold by the overcurrent comparator to achieve overcurrent protection.

[0038] This invention includes a current sampling circuit, a current amplification circuit, and an overcurrent comparator, such as... Figure 1The first N-type MOSFET NM1 and the second N-type MOSFET NM2 constitute a current sampling circuit. The third N-type MOSFET NM3, the fourth N-type MOSFET NM4, the fifth N-type MOSFET NM5, the sixth N-type MOSFET NM6, the first P-type MOSFET PM1, the second P-type MOSFET PM2, the third P-type MOSFET PM3, the fourth P-type MOSFET PM4, the fifth P-type MOSFET PM5, the sixth P-type MOSFET PM6, the seventh P-type MOSFET PM7, the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 constitute a current amplification circuit. The overcurrent comparator is a single comparator COMP1, wherein:

[0039] The gates of the first N-type MOSFET NM1 and the second N-type MOSFET NM2 are connected together with the drive signal Driver. The source of the first N-type MOSFET NM1, the positive terminal of the second resistor R2, and the output current terminal IOUT are connected together. The drains of the first N-type MOSFET NM1 and the drains of the second N-type MOSFET NM2 are connected together with the input power supply voltage terminal VIN.

[0040] The gate of the second N-type MOSFET NM2, the gate of the first N-type MOSFET NM1, and the drive signal Driver are connected together. The source of the second N-type MOSFET NM2, the positive terminal of the first resistor R1, and the source of the seventh P-type MOSFET PM7 are connected together. The drain of the second N-type MOSFET NM2, the drain of the first N-type MOSFET NM1, and the input power supply voltage terminal VIN are connected together.

[0041] The gates of the third N-type MOSFET NM3 and the fourth N-type MOSFET NM4 are connected together with the second reference voltage REF2. The source of the third N-type MOSFET and the drain of the fifth N-type MOSFET NM5 are connected together. The drain of the third N-type MOSFET, the drain of the fifth P-type MOSFET PM5, the gate of the fifth P-type MOSFET PM5, the gate of the first P-type MOSFET PM1, and the gate of the second P-type MOSFET PM2 are connected together.

[0042] The gate of the fourth N-type MOSFET NM4, the gate of the third N-type MOSFET NM3, and the second reference voltage REF2 are connected together. The source of the fourth N-type MOSFET and the drain of the sixth N-type MOSFET NM6 are connected together. The drain of the fourth N-type MOSFET NM4, the gate of the seventh P-type MOSFET PM7, and the negative terminal of the third resistor R3 are connected together.

[0043] The gates of the fifth N-type MOSFET NM5 and the sixth N-type MOSFET NM6 are connected together with the first reference voltage REF1. The source of the fifth N-type MOSFET, the gate of the sixth N-type MOSFET NM6, the negative terminal of the fourth resistor R4, and the ground terminal GND are connected together. The drain of the fifth N-type MOSFET is connected to the source of the third N-type MOSFET NM3.

[0044] The gate of the sixth N-type MOSFET NM6, the gate of the fifth N-type MOSFET NM5, and the first reference voltage REF1 are connected together. The source of the sixth N-type MOSFET, the gate of the fifth N-type MOSFET NM5, the negative terminal of the fourth resistor R4, and the ground terminal GND are connected together. The drain of the sixth N-type MOSFET is connected to the source of the fourth N-type MOSFET NM4.

[0045] The gate of the first P-type MOSFET PM1, the drain of the third N-type MOSFET NM3, the drain of the fifth P-type MOSFET PM5, the gate of the fifth P-type MOSFET PM5, the gate of the second P-type MOSFET PM2, and the gate of the sixth P-type MOSFET PM6 are connected together. The source of the first P-type MOSFET is connected to the source of the third P-type MOSFET PM3, and the drain of the first P-type MOSFET is connected to the negative terminal of the first resistor R1.

[0046] The gates of the second P-type MOSFET PM2, the first P-type MOSFET PM1, the drain of the third N-type MOSFET NM3, the drain of the fifth P-type MOSFET PM5, the gate of the fifth P-type MOSFET PM5, and the gate of the sixth P-type MOSFET PM6 are connected together. The source of the second P-type MOSFET is connected to the source of the fourth P-type MOSFET PM4, and the drain of the second P-type MOSFET is connected to the negative terminal of the second resistor R2.

[0047] The gate of the third P-type MOSFET PM3, the drain of the third P-type MOSFET PM3, the gate of the fourth P-type MOSFET PM4, and the source of the fifth P-type MOSFET PM5 are connected together. The source of the third P-type MOSFET is connected to the source of the first P-type MOSFET PM1. The drain of the third P-type MOSFET, the gate of the third P-type MOSFET PM3, the gate of the fourth P-type MOSFET PM4, and the source of the fifth P-type MOSFET PM5 are connected together.

[0048] The gate of the fourth P-type MOSFET PM4, the gate of the third P-type MOSFET PM3, the drain of the third P-type MOSFET PM3, and the source of the fifth P-type MOSFET PM5 are connected together. The source of the fourth P-type MOSFET is connected to the source of the second P-type MOSFET PM2, and the drain of the fourth P-type MOSFET is connected to the source of the sixth P-type MOSFET PM6.

[0049] The gates of the fifth P-type MOSFET PM5, the first P-type MOSFET PM1, the drain of the third N-type MOSFET NM3, the drain of the fifth P-type MOSFET PM5, the gate of the second P-type MOSFET PM2, and the gate of the sixth P-type MOSFET PM6 are connected together. The source of the fifth P-type MOSFET, the gate of the third P-type MOSFET PM3, the drain of the third P-type MOSFET PM3, and the gate of the fourth P-type MOSFET PM4 are connected together. The drains of the fifth P-type MOSFET, the gate of the fifth P-type MOSFET PM5, the gate of the first P-type MOSFET PM1, the drain of the third N-type MOSFET NM3, the gate of the second P-type MOSFET PM2, and the gate of the sixth P-type MOSFET PM6 are connected together.

[0050] The gate of the sixth P-type MOSFET PM6, the gate of the first P-type MOSFET PM1, the drain of the third N-type MOSFET NM3, the drain of the fifth P-type MOSFET PM5, the gate of the fifth P-type MOSFET PM5, and the gate of the second P-type MOSFET PM2 are connected together. The source of the sixth P-type MOSFET and the drain of the fourth P-type MOSFET PM4 are connected. The drain of the sixth P-type MOSFET is connected to the positive terminal of the third resistor R3.

[0051] The gate of the seventh P-type MOSFET PM7, the negative terminal of the third resistor R3, and the drain of the fourth N-type MOSFET NM4 are connected together. The source of the seventh P-type MOSFET, the positive terminal of the first resistor R1, and the source of the second N-type MOSFET NM2 are connected together. The drain of the seventh P-type MOSFET, the positive terminal of the fourth resistor R4, the non-inverting input terminal of the comparator COMP1, and the current limiting input terminal ILIM are connected together.

[0052] The positive terminal of the first resistor R1 is connected to the source of the second N-type MOSFET NM2 and the source of the seventh P-type MOSFET PM7, and the negative terminal of the first resistor is connected to the drain of the first P-type MOSFET PM1.

[0053] The positive terminal of the second resistor R2 is connected to the source and output current terminal IOUT of the first N-type MOSFET NM1, and the negative terminal of the second resistor is connected to the drain of the second P-type MOSFET PM2.

[0054] The positive terminal of the third resistor R3 is connected to the drain of the sixth P-type MOSFET PM6, and the negative terminal of the third resistor is connected to the drain of the fourth N-type MOSFET NM4 and the gate of the seventh P-type MOSFET PM7.

[0055] The positive terminal of the fourth resistor R4, the drain of the seventh P-type MOSFET PM7, the positive input terminal of the comparator COMP1, and the current limiting input terminal ILIM are connected together. The negative terminal of the fourth resistor is connected to the source of the fifth N-type MOSFET NM5, the source of the sixth N-type MOSFET NM6, and the ground terminal GND.

[0056] The positive input terminal of comparator COMP1, the drain of the seventh P-type MOSFET PM7, the positive terminal of the fourth resistor R4, and the current limiting input terminal ILIM are connected together. The negative input terminal of comparator COMP1 is connected to the third reference voltage REF3.

[0057] In this embodiment, the current sampling circuit samples the output current IOUT through the on-resistance of the power MOSFET (first N-type MOSFET NM1). The sampled signal is sent to the current amplification circuit and converted into a current at the current-limiting input ILIM terminal. The sampled current is converted into a voltage through an external resistor connected to the ILIM terminal, and then compared with the threshold set by the third reference voltage REF3 through the overcurrent comparator COMP1, thereby achieving the purpose of overcurrent protection. The method of sampling the current through the on-resistance of the first N-type MOSFET NM1 eliminates the need for additional current sampling devices. The current mirroring method used in the current amplification circuit avoids the problem of large temperature drift of the overcurrent protection threshold caused by large changes in on-resistance with temperature. At the same time, the fourth resistor R4 connected to the ILIM terminal allows for easy programmable design of the overcurrent protection threshold, expanding the application range of this overcurrent protection sampling control circuit.

[0058] To make the technical means and creative features of this invention easier to understand, the working principle of this invention will be further explained in conjunction with the accompanying drawings:

[0059] The current sampling circuit consists of a first N-type MOSFET NM1 and a second N-type MOSFET NM2. First, the output current IOUT is sampled by the on-resistance of the first N-type MOSFET NM1, which serves as the power MOSFET, to obtain the sampling voltage V1. Then, through the mirroring effect between the second N-type MOSFET NM2 and the first N-type MOSFET NM1, the current of the first N-type MOSFET NM1 is proportionally mirrored to the second N-type MOSFET NM2. This process can be represented as:

[0060]

[0061] in, V is the sampling voltage; IN I is the input power supply voltage. OUT For the output current, r O_NM1 This is the on-resistance of the first N-type MOSFET.

[0062] The current amplifier circuit uses a negative feedback operational amplifier to mirror the sampled voltage V1 to a new voltage, namely the mirrored sampled voltage V2. This V2 is then converted into a current I through the on-resistance of the first N-type MOSFET NM1, which is then used to power the current I of the seventh P-type MOSFET PM7. PM7 This achieves current mirroring between the first N-type MOSFET NM1 and the second N-type MOSFET NM2. This process can be represented as:

[0063]

[0064] Where, r O_NM2 It is the on-resistance of NM2 in the MOSFET.

[0065] The overcurrent comparator includes a comparator and COMP1, which is used when the current I... PM7 When the voltage across the fourth resistor R4 exceeds the third reference voltage REF3, comparator COMP1 reverses, indicating an overcurrent condition.

[0066]

[0067] As can be seen from the above equation, the on-resistance r of the first N-type MOSFET NM1, which serves as the power MOSFET, is... O_NM1 The output current IOUT is sampled, and the on-resistance r of the second N-type MOSFET NM2 is introduced simultaneously. O_NM2 The current sampling signal is mirrored, and then the mirrored current is converted into voltage through an external fourth resistor R4. Overcurrent detection is achieved through an overcurrent comparator. The external fourth resistor R4 can also be adjusted to achieve more flexible control of the overcurrent protection threshold.

[0068] Appendix Figure 2 This refers to the overcurrent protection threshold when the external resistor R4 is selected with different resistance values. When R4=3KΩ, the overcurrent protection threshold is about 5A (the value measured in this embodiment is 5.2059A); when R4=5KΩ, the overcurrent protection threshold is about 3A (the value measured in this embodiment is 3.066A); when R4=10KΩ, the overcurrent protection threshold is about 1.5A (the value measured in this embodiment is 1.506A).

[0069] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A programmable overcurrent protection sampling control circuit applied to a load switch, characterized in that, It includes a current sampling circuit, a current amplification circuit, and an overcurrent comparator. The current sampling circuit samples the output current through the on-resistance of the power MOSFET. The sampled signal is sent to the current amplification circuit and converted into a current at the current-limiting input terminal. The sampled current is converted into a voltage through the resistor connected to the current-limiting input terminal. Then, the overcurrent comparator compares the voltage with the set voltage threshold to achieve overcurrent protection.

2. The programmable overcurrent protection sampling control circuit for load switches according to claim 1, characterized in that, The current sampling circuit is used to sample the current at the output current terminal. The current sampling circuit consists of two N-type MOSFETs, wherein: The gates of the first N-type MOS transistor and the second N-type MOS transistor are connected to the drive signal terminal; The drains of the first N-type MOSFET and the second N-type MOSFET are connected to the input power supply voltage terminal; The source of the first N-type MOS transistor serves as the first output terminal of the current sampling circuit, and is connected to the output current terminal and the current amplification circuit. The source of the second N-type MOS transistor serves as the second output terminal of the current sampling circuit, which is connected to the current amplification circuit.

3. The programmable overcurrent protection sampling control circuit for load switches according to claim 2, characterized in that, The current amplifier circuit includes four N-type MOSFETs, seven P-type MOSFETs, and four resistors, wherein: One end of the first resistor is connected to the source of the seventh P-type MOS transistor and the second output terminal of the current sampling circuit, and the other end is connected to the drain of the first P-type MOS transistor. One end of the second resistor is connected to the first output terminal of the current sampling circuit, and the other end is connected to the drain of the second P-type MOS transistor. The gates of the first P-type MOS transistor, the gates of the second P-type MOS transistor, the gates and drains of the fifth P-type MOS transistor, the gate of the sixth P-type MOS transistor, and the drain of the third N-type MOS transistor are connected together, and the source of the first P-type MOS transistor is connected to the source of the third P-type MOS transistor. The source of the second P-type MOSFET is connected to the source of the fourth P-type MOSFET; The gate and drain of the third P-type MOS transistor, the gate of the fourth P-type MOS transistor, and the source of the fifth P-type MOS transistor are connected together; The drain of the fourth P-type MOSFET is connected to the source of the sixth P-type MOSFET; The drain of the sixth P-type MOSFET is connected to one end of the third resistor, and the other end of the third resistor is connected to the gate of the seventh P-type MOSFET and the drain of the fourth N-type MOSFET. The drain of the seventh P-type MOSFET, one end of the fourth resistor, and the current-limiting input terminal serve as the positive input of the overcurrent comparator. The gates of the third and fourth N-type MOS transistors are connected to the second reference voltage, and the source of the third N-type MOS transistor is connected to the drain of the fifth N-type MOS transistor. The source of the fourth N-type MOSFET is connected to the drain of the sixth N-type MOSFET; The gates of the fifth and sixth N-type MOS transistors are connected to the first reference voltage, and the sources of the fifth and sixth N-type MOS transistors, as well as the other end of the fourth resistor, are connected to the ground terminal.

4. A programmable overcurrent protection sampling control circuit for a load switch according to claim 2 or 3, characterized in that, The on-resistance of the first N-type MOSFET is used to sample the output current to obtain a sampled voltage, which is then output from the first output terminal of the current sampling circuit. Through the mirroring effect of the first and second N-type MOSFETs, the current of the first N-type MOSFET is mirrored to the second N-type MOSFET proportionally.

5. A programmable overcurrent protection sampling control circuit for a load switch according to claim 4, characterized in that, The process of sampling the output current to obtain the sampling voltage by the on-resistance of the first N-type MOSFET includes: in, V is the sampling voltage; IN I is the input power supply voltage. OUT For the output current, r O_NM1 This is the on-resistance of the first N-type MOSFET.

6. A programmable overcurrent protection sampling control circuit for a load switch according to claim 4, characterized in that, The operational amplifier with negative feedback in the current amplification circuit mirrors the sampled voltage to the second output terminal of the current sampling circuit. The mirrored sampled voltage is then converted into the current of the seventh P-type MOSFET through the on-resistance of the first N-type MOSFET, thus realizing the current mirroring of the first N-type MOSFET and the second N-type MOSFET.

7. A programmable overcurrent protection sampling control circuit for a load switch according to claim 6, characterized in that, The current of the seventh P-type MOSFET is expressed as follows: in, This refers to the current of the seventh P-type MOSFET; The sampled voltage is obtained by mirroring; V is the sampling voltage; IN I is the input power supply voltage. OUT For the output current, r O_NM2 This is the on-resistance of the second N-type MOSFET.

8. A programmable overcurrent protection sampling control circuit for a load switch according to claim 3, characterized in that, The negative input of the overcurrent comparator is the third reference voltage. When the voltage across the fourth resistor exceeds the current of the seventh P-type MOSFET, the overcurrent comparator reverses, indicating an overcurrent condition. The following conditions must be met for an overcurrent to occur: Among them, I OUT For the output current, r O_NM1 r is the on-resistance of the first N-type MOSFET. O_NM2 R4 is the on-resistance of the second N-type MOSFET, R4 is the resistance of the fourth resistor, and REF3 is the third reference voltage.

9. A programmable overcurrent protection sampling control circuit for a load switch according to claim 8, characterized in that, The fourth resistor is an externally programmable resistor, and the overcurrent threshold can be adjusted by controlling the resistance value of the fourth resistor.

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