Low-power-consumption power supply over-current and over-voltage protection method

Abstract

The invention discloses a low-power-consumption power supply over-current and over-voltage protection method, and relates to the related field of electronic technology, and the method comprises the steps: connecting a current sampling resistor in series between an input power supply and a system load power supply; an input power supply generates a positive voltage signal and a negative voltage signal through a current sampling resistor, the positive voltage signal and the negative voltage signal are subjected to differential amplification through an operational amplifier, and a differential voltage signal is output; and performing level conversion on the differential voltage signal, outputting a control voltage signal, and performing on-off control on the electronic switch according to the control voltage signal. The technical problems of insufficient flexibility, unsatisfactory protection effect and high power consumption of the existing power supply over-current and over-voltage protection are solved, and the technical effects of enhancing flexibility, being safe and reliable and reducing power consumption are achieved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a low-power power supply over-current and over-voltage protection method. Background Art

[0002] In electronic devices, the stability and safety of the power supply system are crucial. However, due to component damage, design defects or external factors, high current phenomena often occur in electronic circuits, which may not only burn electronic components, but also cause damage to circuit boards in severe cases, and even cause open fire accidents. The existing technology uses the built-in overcurrent protection function of the power chip to promptly cut off the power supply to the subsequent power branch to prevent damage caused by excessive current. However, not all power chips have overcurrent protection functions, and for functional devices with higher peak power requirements, the output power design of the power chip often leaves a large margin to cope with instantaneous high power requirements. This margin is difficult to provide effective protection in short-circuit conditions. In addition, the protection method through external fuses consumes high power.

[0003] In the current related technologies, power supply overcurrent and overvoltage protection has technical problems such as insufficient flexibility, unsatisfactory protection effect and high power consumption. Summary of the invention

[0004] The present application provides a low-power power supply over-current and over-voltage protection method, which adopts a current sampling resistor connected in series between the input power supply and the system load power supply, uses the positive voltage signal and the negative voltage signal generated by the resistor to perform differential amplification, outputs a differential voltage signal, performs level conversion on the differential voltage signal to obtain a control voltage signal, and controls the on and off of an electronic switch according to the control voltage signal, etc., to provide a simple over-current protection circuit, thereby achieving the technical effects of enhanced flexibility, safety and reliability, and reduced power consumption.

[0005] The present application provides a low-power power supply overcurrent and overvoltage protection method, comprising:

[0006] A current sampling resistor is connected in series between the input power supply and the system load power supply; the input power supply generates a positive voltage signal and a negative voltage signal through the current sampling resistor, and the positive voltage signal and the negative voltage signal are differentially amplified by an operational amplifier to output a differential voltage signal; the differential voltage signal is level-converted to output a control voltage signal, and the electronic switch is controlled on and off according to the control voltage signal.

[0007] In a possible implementation, the current sampling resistor is a milliohm-level resistor.

[0008] In a possible implementation, the input power generates a positive voltage signal and a negative voltage signal through a current sampling resistor, and the following processing is performed:

[0009] The input power source passes through the current sampling resistor to collect the front-end voltage and the rear-end voltage; the voltage signal of the front-end voltage after passing through the fourth series resistor is used as the positive voltage signal, and the voltage signal of the rear-end voltage after passing through the third series resistor is used as the negative voltage signal.

[0010] In a possible implementation, an operational amplifier is used to differentially amplify the positive voltage signal and the negative voltage signal, output a differential voltage signal, and perform the following processing:

[0011] The positive voltage signal is transmitted to the positive input terminal of the first operational amplifier, and the negative voltage signal is input to the negative input terminal of the first operational amplifier, and a first differential voltage signal is output, wherein the first differential voltage signal is fed back to the negative input terminal of the first operational amplifier using a first series resistor to form a negative feedback loop; and the first differential voltage signal is differentially amplified using a second operational amplifier to output the differential voltage signal.

[0012] In a possible implementation, the following processing is performed:

[0013] A voltage divider circuit is formed by using a fifth series resistor and a sixth series resistor to configure a first reference voltage; the first reference voltage is amplified by using a third operational amplifier to output a preset reference voltage; the preset reference voltage is connected to the positive input terminal of the first operational amplifier by using a second series resistor; wherein the first series resistor, the second series resistor, the third series resistor, the fourth series resistor, the fifth series resistor and the sixth series resistor have a specific proportional relationship.

[0014] In a possible implementation, the following processing is performed:

[0015] Configure a first calculation formula and a second calculation formula; the first calculation formula is: Wherein, Vref is a preset reference voltage, R5 is the resistance value of the fifth series resistor, R6 is the resistance value of the sixth series resistor, and VIN is the input voltage; the second calculation formula is: Among them, OUT is the differential voltage signal, Is is the input current, Rs is the resistance value of the current sampling resistor, R2 is the resistance value of the second series resistor, R4 is the resistance value of the fourth series resistor, and Vref is the preset reference voltage.

[0016] In a possible implementation, the differential voltage signal is level-converted, a control voltage signal is output, and the following processing is performed:

[0017] A critical voltage value is calculated based on the first calculation formula and the second calculation formula; the differential voltage signal is judged according to the critical voltage value, and if the differential voltage signal is less than the critical voltage value, the level conversion circuit outputs a path control signal to the electronic switch; if the differential voltage signal is greater than or equal to the critical voltage value, the level conversion circuit outputs a reverse path control signal to the electronic switch.

[0018] In a possible implementation, when a reverse path control signal is generated, an alarm device is synchronously activated to give an audible and visual alarm.

[0019] A low-power power supply overcurrent and overvoltage protection method proposed in this application is to first connect a current sampling resistor in series between the input power supply and the system load power supply. The input power supply generates a positive voltage signal and a negative voltage signal through the current sampling resistor. The positive voltage signal and the negative voltage signal are differentially amplified by an operational amplifier to output a differential voltage signal. Finally, the differential voltage signal is level-converted to output a control voltage signal. The electronic switch is controlled on and off according to the control voltage signal, thereby achieving the technical effects of enhanced flexibility, safety and reliability, and reduced power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the accompanying drawings of the embodiment of the present invention will be briefly introduced below. A flow chart is used in the present application to illustrate the operations performed by the method according to the embodiment of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps can be processed in reverse order or simultaneously as needed. At the same time, other operations can also be added to these processes, or one or more operations can be removed from these processes.

[0021] Figure 1 A flowchart of a low-power power supply over-current and over-voltage protection method provided in an embodiment of the present application.

[0022] Figure 2 A schematic diagram of the principle structure of a low-power power supply over-current and over-voltage protection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0024] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0025] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict, and the terms "first\second" involved are merely to distinguish similar objects and do not represent a specific ordering of objects. The terms "including" and "having" and any variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products, or devices. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by technicians in the technical field of this application. The terms used herein are for the purpose of describing the embodiments of the present application only.

[0026] The present application provides a low-power power supply over-current and over-voltage protection method. Figure 1 As shown, the method includes:

[0027] Step S100, a current sampling resistor is connected in series between an input power supply and a system load power supply; Step S200, the input power supply generates a positive voltage signal and a negative voltage signal through the current sampling resistor, and the positive voltage signal and the negative voltage signal are differentially amplified by an operational amplifier to output a differential voltage signal; Step S300, the differential voltage signal is level-converted to output a control voltage signal, and the electronic switch is controlled on and off according to the control voltage signal.

[0028] Specifically, if Figure 2 As shown in Figure 1, the current sampling resistor (Rs) is a resistor used to detect the current flowing through it and generate a corresponding voltage drop. The resistance of the current sampling resistor (Rs) needs to be small enough to generate a measurable voltage drop without consuming too much power. The current sampling resistor (Rs) is connected in series between the input power supply (the device or system that provides power, such as AC power, battery or other power supply) and the system load power supply (the power supply that provides power to the system load, such as circuit boards, motors, etc., such as a power management module or a power supply that directly supplies power to the load). In this way, when the current flows through the load, it will also flow through the current sampling resistor (Rs).

[0029] When current flows through the current sampling resistor (Rs), a voltage drop will be generated across the resistor. This voltage drop can be regarded as two voltage signals: the positive voltage signal (IN+) and the negative voltage signal (IN-). The positive voltage signal (IN+) and the negative voltage signal (IN-) are respectively input to the positive input terminal and the negative input terminal of the operational amplifier for differential amplification to obtain a differential voltage signal.

[0030] A critical voltage value for judging overcurrent and overvoltage is obtained, and the differential voltage signal is compared with the critical voltage value. If the differential voltage signal is less than the critical voltage value, it indicates that the current current or voltage is within a safe range, and at this time, the level conversion circuit controls the electronic switch (N1) to maintain the path state; if the differential voltage signal is greater than or equal to the critical voltage value, it indicates that an overcurrent or overvoltage situation has occurred, and at this time, the level conversion circuit controls the electronic switch (N1) to cut off the path state. The embodiment of the present application adopts a current sampling resistor connected in series between the input power supply and the system load power supply, and the positive and negative voltage signals generated by the resistor are differentially amplified to output a differential voltage signal, and the differential voltage signal is level converted to obtain a control voltage signal. The electronic switch is controlled on and off according to the control voltage signal, and other technical means are provided to provide a simple overcurrent protection circuit, which achieves the technical effects of enhanced flexibility, safety and reliability, and reduced power consumption.

[0031] In a possible implementation manner, the current sampling resistor is a milliohm-level resistor.

[0032] Specifically, the resistance of the milliohm resistor is relatively small, so when current passes through it, the voltage drop across it is also small, that is, within the normal current range, the power consumed by the sampling resistor will be relatively low, reducing the power consumption of the entire circuit system. Smaller current sampling resistors allow a larger current range to pass without causing excessive voltage drop or power loss on the resistor, ensuring accurate current sampling within a wider current range and improving sampling accuracy. Since the resistance of the milliohm resistor is small, the power consumed by it is also small, so the heat generation is relatively low, reducing the temperature rise of the resistor, maintaining the stability of its resistance value, and avoiding performance degradation or damage due to overheating.

[0033] In a possible implementation, the input power generates a positive voltage signal and a negative voltage signal through a current sampling resistor, and step S200 further includes step S210, in which the input power passes through the current sampling resistor to collect the front-end voltage and the rear-end voltage; in step S220, the voltage signal after the front-end voltage passes through the fourth series resistor is used as the positive voltage signal, and the voltage signal after the rear-end voltage passes through the third series resistor is used as the negative voltage signal.

[0034] Specifically, Figure 2As shown, a current sampling resistor (Rs) is connected in series in the circuit of the input power supply, and the two ends of the current sampling resistor (Rs) are called the front end and the back end respectively. The front end voltage refers to the voltage before the current flows through the current sampling resistor (Rs), and the back end voltage refers to the voltage after the current flows through the current sampling resistor (Rs). By measuring these two voltages, the current value flowing through the current sampling resistor (Rs) can be calculated. The front end voltage is divided by a fourth series resistor (R4), and then the divided voltage signal is output as the positive voltage signal (IN+). Similarly, the back end voltage is divided by a third series resistor (R3), and then the divided voltage signal is output as the negative voltage signal (IN-). This implementation method divides the front end voltage and the back end voltage through a series resistor to obtain a voltage signal suitable for subsequent circuit processing, ensuring the accuracy and stability of the signal during transmission and processing.

[0035] In one possible implementation, an operational amplifier is used to differentially amplify the positive voltage signal and the negative voltage signal to output a differential voltage signal. Step S200 further includes step S230, transmitting the positive voltage signal to the positive input terminal of the first operational amplifier, inputting the negative voltage signal to the negative input terminal of the first operational amplifier, and outputting a first differential voltage signal, wherein the first differential voltage signal is fed back to the negative input terminal of the first operational amplifier using a first series resistor to form a negative feedback loop; step S240, differentially amplifying the first differential voltage signal using a second operational amplifier to output the differential voltage signal.

[0036] Specifically, Figure 2 As shown, the positive voltage signal (IN+) is connected to the positive input terminal (non-inverting input terminal, + terminal) of the first operational amplifier (OP1), and the negative voltage signal (IN-) is connected to the negative input terminal (inverting input terminal, - terminal) of the first operational amplifier (OP1). The first operational amplifier (OP1) amplifies according to the difference between the input positive voltage signal (IN+) and the negative voltage signal (IN-). If the positive voltage is higher than the negative voltage, a positive differential voltage signal is output; otherwise, a negative differential voltage signal is output. The first series resistor (R1) is connected between the output terminal and the negative input terminal of the first operational amplifier (OP1) to form a negative feedback loop, and the negative feedback is used to stabilize the gain of the operational amplifier, reduce distortion, and help the operational amplifier maintain a linear operating area. When the output signal increases, the signal fed back to the negative input terminal through the first series resistor (R1) will also increase, causing the output of the operational amplifier to decrease, thereby forming a self-regulating negative feedback system.

[0037] The first differential voltage signal output by the first operational amplifier (OP1) is used as the input signal of the second operational amplifier (OP2). This signal is connected to the positive input terminal of the second operational amplifier (OP2), and the second operational amplifier (OP2) further performs differential amplification on the input first differential voltage signal and outputs the final differential voltage signal. Since the second operational amplifier (OP2) works as a follower, its output has a higher driving capability and can drive the level conversion circuit more effectively. The input impedance of the second operational amplifier (OP2) is very high, which is used to reduce the impact on the output impedance of the first operational amplifier (OP1), thereby maintaining the stability of the circuit. This implementation method effectively suppresses common-mode noise and interference through two-stage differential amplification, and improves the signal-to-noise ratio and clarity of the signal.

[0038] In a possible implementation, step S300 further includes step S310, using the fifth series resistor and the sixth series resistor to form a voltage divider circuit to configure a first reference voltage; step S320, using the third operational amplifier to amplify the first reference voltage and output a preset reference voltage; step S330, using the second series resistor to connect the preset reference voltage to the positive input terminal of the first operational amplifier; wherein the first series resistor, the second series resistor, the third series resistor, the fourth series resistor, the fifth series resistor and the sixth series resistor have a specific proportional relationship.

[0039] Specifically, Figure 2 As shown, a voltage divider circuit is formed by using a fifth series resistor (R5) and a sixth series resistor (R6), and the input voltage is divided to obtain a lower voltage value as the first reference voltage. The first reference voltage is amplified by using a third operational amplifier (OP3), and the amplitude of the first reference voltage is adjusted to match the voltage signal after differential amplification. By adjusting the amplification factor of the third operational amplifier (OP3), the required preset reference voltage (Vref) is obtained. The preset reference voltage (Vref) is connected to the positive input terminal of the first operational amplifier (OP1) by using a second series resistor (R2), so that the first operational amplifier (OP1) can compare the voltage signal after differential amplification with the preset reference voltage (Vref), thereby outputting a control voltage signal. There is a specific proportional relationship between the first series resistor (R1), the second series resistor (R2), the third series resistor (R3), the fourth series resistor (R4), the fifth series resistor (R5) and the sixth series resistor (R6), and these proportional relationships are used to ensure the correct operation of the circuit, including the output voltage of the voltage divider circuit, the amplification factor of the operational amplifier and the threshold setting of the entire protection circuit. This implementation ensures the accuracy and stability of the preset reference voltage (Vref) by configuring a voltage divider circuit and a third operational amplifier (OP3), thereby achieving high-precision and high-stability power supply over-current and over-voltage protection.

[0040] In a possible implementation, the method further includes: configuring a first calculation formula and a second calculation formula; the first calculation formula is: Wherein, Vref is a preset reference voltage, R5 is the resistance value of the fifth series resistor, R6 is the resistance value of the sixth series resistor, and VIN is the input voltage; the second calculation formula is: Among them, OUT is the differential voltage signal, Is is the input current, Rs is the resistance value of the current sampling resistor, R2 is the resistance value of the second series resistor, R4 is the resistance value of the fourth series resistor, and Vref is the preset reference voltage.

[0041] Specifically, the first calculation formula is used to set the preset reference voltage (Vref), and the second calculation formula is used to calculate the differential voltage signal (OUT). These two signals together determine the threshold and sensitivity of the protection circuit. By adjusting the resistance value of the relevant resistor, these parameters can be flexibly set to adapt to different application scenarios and requirements.

[0042] In one possible implementation, the differential voltage signal is level-converted to output a control voltage signal, and step S300 further includes step S340, calculating a critical voltage value based on the first calculation formula and the second calculation formula; step S350, judging the differential voltage signal according to the critical voltage value, if the differential voltage signal is less than the critical voltage value, the level conversion circuit outputs a path control signal to the electronic switch; step S360, if the differential voltage signal is greater than or equal to the critical voltage value, the level conversion circuit outputs a reverse path control signal to the electronic switch.

[0043] Specifically, the critical voltage value is a specific threshold value that the differential voltage signal (OUT) in the circuit needs to reach, which is used to trigger the protection mechanism. This value is set according to the protection requirements and design parameters of the circuit. The second calculation formula is used to calculate the relationship between the differential voltage signal (OUT) and the preset reference voltage (Vref). When the differential voltage signal (OUT) reaches the critical voltage value, the value of the preset reference voltage (Vref) can be inferred by this formula. The first calculation formula is used to calculate the relationship between the preset reference voltage (Vref) and the input voltage VIN and the resistors R5 and R6. By adjusting the values ​​of R5 and R6, the value of the preset reference voltage (Vref) can be changed. After determining the value of the preset reference voltage (Vref), select the appropriate values ​​of R5 and R6 to meet the conditions of the first calculation formula. The adjustment of the resistance value can be achieved by replacing the resistor or adjusting the resistance value of the adjustable resistor. After adjusting the resistance value, a circuit test is performed to verify whether the differential voltage signal (OUT) can trigger the protection mechanism when the critical voltage value is reached. When the differential voltage signal (OUT) is less than the critical voltage value, it means that the current current or voltage has not reached the protection threshold of overcurrent or overvoltage, so the level conversion circuit outputs a path control signal to the electronic switch (N1), and this path control signal is used to keep the electronic switch (N1) in a closed state, allowing the current to pass normally. When the differential voltage signal (OUT) is greater than or equal to the critical voltage value, it means that the current current or voltage has exceeded the preset protection threshold, so the level conversion circuit outputs a reverse path control signal to the electronic switch (N1), and this reverse path control signal is opposite to the path control signal, and is used to trigger the disconnection of the electronic switch (N1), thereby cutting off the current and protecting the circuit from damage. Among them, the level conversion circuit is used to convert the differential voltage signal (OUT) into a level signal suitable for the control of the electronic switch (N1). This implementation method realizes effective protection of the power supply from overcurrent and overvoltage by calculating the critical voltage value, judging the differential voltage signal (OUT) and outputting the corresponding control signal to the electronic switch (N1).

[0044] In a possible implementation, step S360 further includes step S361, when a reverse path control signal is generated, synchronously activating an alarm device to sound and light alarm.

[0045] Specifically, when the reverse path control signal is generated, the alarm device is activated synchronously, and the alarm device includes an audible alarm (such as a buzzer) and a light alarm (such as an LED indicator) to send an obvious warning signal to the operator, reminding them that the circuit is in an unsafe state. The audible and light alarms remind the operator to pay attention and take necessary measures, thereby improving the safety of the entire system.

[0046] The above specific implementation manner does not constitute a limitation to the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. In some cases, the actions or steps recorded in the present application can be performed in an order different from that in the embodiment and can still achieve the desired results. In addition, the process depicted in the accompanying drawings does not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. A low-power power supply over-current and over-voltage protection method, characterized in that: include: Connect a current sampling resistor in series between the input power supply and the system load power supply; The input power generates a positive voltage signal and a negative voltage signal through a current sampling resistor, and the positive voltage signal and the negative voltage signal are differentially amplified by an operational amplifier to output a differential voltage signal; The differential voltage signal is level-converted to output a control voltage signal, and the on-off of the electronic switch is controlled according to the control voltage signal.

2. A low-power power supply over-current and over-voltage protection method according to claim 1, characterized in that: The current sampling resistor is a milliohm-level resistor.

3. A low-power power supply over-current and over-voltage protection method according to claim 1, characterized in that: The input power generates positive voltage signal and negative voltage signal through the current sampling resistor, including: The input power passes through the current sampling resistor to collect the front-end voltage and the back-end voltage; The voltage signal after the front-end voltage passes through the fourth series resistor is used as the positive voltage signal, and the voltage signal after the rear-end voltage passes through the third series resistor is used as the negative voltage signal.

4. A low-power power supply over-current and over-voltage protection method according to claim 3, characterized in that: The positive voltage signal and the negative voltage signal are differentially amplified by an operational amplifier to output a differential voltage signal, including: The positive voltage signal is transmitted to the positive input terminal of the first operational amplifier, and the negative voltage signal is input to the negative input terminal of the first operational amplifier to output a first differential voltage signal, wherein the first differential voltage signal is fed back to the negative input terminal of the first operational amplifier by using a first series resistor to form a negative feedback loop; The first differential voltage signal is differentially amplified by a second operational amplifier to output the differential voltage signal.

5. A low-power power supply over-current and over-voltage protection method according to claim 4, characterized in that: Also includes: Using the fifth series resistor and the sixth series resistor to form a voltage divider circuit to configure a first reference voltage; amplifying the first reference voltage using a third operational amplifier to output a preset reference voltage; Connecting the preset reference voltage to the positive input terminal of the first operational amplifier using a second series resistor; There is a specific proportional relationship among the first series resistor, the second series resistor, the third series resistor, the fourth series resistor, the fifth series resistor and the sixth series resistor.

6. A low-power power supply over-current and over-voltage protection method according to claim 5, characterized in that: Also includes: Configure a first calculation formula and a second calculation formula; The first calculation formula is: Wherein, Vref is a preset reference voltage, R5 is the resistance value of the fifth series resistor, R6 is the resistance value of the sixth series resistor, and VIN is the input voltage; The second calculation formula is: Among them, OUT is the differential voltage signal, Is is the input current, Rs is the resistance value of the current sampling resistor, R2 is the resistance value of the second series resistor, R4 is the resistance value of the fourth series resistor, and Vref is the preset reference voltage.

7. A low-power power supply over-current and over-voltage protection method according to claim 6, characterized in that: Performing level conversion on the differential voltage signal and outputting a control voltage signal, comprising: Calculate the critical voltage value based on the first calculation formula and the second calculation formula; The differential voltage signal is judged according to the critical voltage value, and if the differential voltage signal is less than the critical voltage value, the level conversion circuit outputs a path control signal to the electronic switch; If the differential voltage signal is greater than or equal to the critical voltage value, the level conversion circuit outputs a reverse path control signal to the electronic switch.

8. A low-power power supply over-current and over-voltage protection method according to claim 7, characterized in that: When a reverse path control signal is generated, the alarm device is synchronously activated to give an audible and visual alarm.

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