Power management circuit and power supply
By designing a current direction detection module and a line switching module in the power management circuit, the problem of load current backflow was solved, and the normal operation and protection of the power supply were realized.
Patent Information
- Application Number
- CN202423317667.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2034-12-31
AI Technical Summary
In existing technologies, load current reverse flow can affect the normal operation of power supplies and even cause damage. How to avoid current reverse flow has become an important issue in power supply applications.
Design a power management circuit including a current direction detection module and a line switching module. By detecting the current direction and controlling the state of the first switching transistor, current backflow can be prevented.
It effectively prevents backflow of current, protects the normal operation of the power supply, and avoids damage to the power supply.
Smart Images
Figure CN223829030U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of power safety, and in particular to a power management circuit and a power supply. Background Technology
[0002] If a reverse current occurs when a power supply is supplying power to a load, it will affect the normal operation of the power supply or even cause damage to the power supply. Therefore, how to avoid reverse current has become an issue that needs to be addressed in power supply applications. Utility Model Content
[0003] The main purpose of this invention is to propose a power management circuit and power supply, which aims to solve the problem of how to avoid current backflow in the prior art.
[0004] To achieve the above objectives, this utility model provides a power management circuit. The power management circuit is connected to a power supply module and a load. The power management circuit includes a first switching transistor, a current direction detection module, and a line switching module. The drain of the first switching transistor serves as the positive terminal of the power management circuit and is connected to the power supply module. The source of the first switching transistor is connected to the load. The detection terminal of the current direction detection module is located on the line connecting the output terminal of the first switching transistor and the load. The output terminal of the current direction detection module is connected to the control terminal of the line switching module. The moving connection terminal of the line switching module is connected to the gate of the first switching transistor. The first stationary connection terminal of the line switching module is grounded, and the second stationary connection terminal of the line switching module is connected to the source of the first switching transistor. Wherein:
[0005] The current direction detection module is used to detect the current direction on the line to obtain the detection result, and send the control signal corresponding to the detection result to the line switching module.
[0006] The line switching module is used to receive the control signal sent by the current direction detection module, and connect the moving connection terminal to the first stationary connection terminal or the second stationary connection terminal according to the control signal.
[0007] Optionally, the current direction detection module includes a first resistor, a second resistor, and a comparator; wherein:
[0008] The first resistor is connected in series in the line connecting the output of the first switch to the load. The non-inverting input of the comparator is connected to the end of the first resistor closest to the load, and the inverting input of the comparator is connected to the end of the first resistor closest to the first switch. The output of the comparator is connected to the control terminal of the line switching module, and the output of the comparator is also connected to the power supply through the second resistor.
[0009] Optionally, the line switching module includes a signal determination unit and a switching unit; the control terminal of the signal determination unit is connected to the output terminal of the current direction detection module, the output terminal of the signal determination unit is connected to the control terminal of the switching unit, the moving connection terminal of the switching unit is connected to the gate of the first switching transistor, the first stationary connection terminal of the switching unit is grounded, and the second stationary connection terminal of the switching unit is connected to the source of the first switching transistor; wherein:
[0010] The signal determination unit is used to receive the control signal sent by the current direction detection module and output a switching signal corresponding to the control signal to the switching unit;
[0011] The switching unit is used to connect the moving connection end to the first stationary connection end or the second stationary connection end according to the switching signal.
[0012] Optionally, the signal determination unit includes a second switching transistor, wherein:
[0013] The gate of the second switching transistor is connected to the output terminal of the current direction detection module, the source of the second switching transistor is grounded, and the drain of the second switching transistor is connected to the control terminal of the switching unit.
[0014] Optionally, the second switch is an NMOS transistor.
[0015] Optionally, the switching unit includes a relay and a first Zener diode; wherein:
[0016] The first end of the relay coil is connected to the power supply, and the first end of the relay coil is also connected to the negative terminal of the first Zener diode. The positive terminal of the first Zener diode is connected to the second end of the relay coil, and the second end of the relay coil is also connected to the output terminal of the signal determination unit.
[0017] The first contact of the relay is connected to the gate of the first switching transistor, the second contact of the relay is grounded, and the third contact of the relay is connected to the source of the first switching transistor; wherein, the first contact and the second contact form a normally closed contact, and the first contact and the third contact form a normally open contact.
[0018] Optionally, the power management circuit further includes a reverse connection protection module, which is connected between the gate and source of the first switching transistor, wherein:
[0019] The reverse connection protection module is used to turn off the first switch when the power supply module is reverse connected.
[0020] Optionally, the reverse connection protection module includes a second Zener diode, a first capacitor, and a third resistor; wherein:
[0021] The negative terminal of the second Zener diode is connected to the source terminal of the first switching transistor, the positive terminal of the second Zener diode is grounded through the third resistor, and the first capacitor is connected in parallel with the second Zener diode;
[0022] The first static connection terminal of the line switching module is grounded through the third resistor.
[0023] Optionally, the first switching transistor is a PMOS transistor.
[0024] In addition, to achieve the above objectives, the present invention also provides a power supply, which includes a power supply module and a power management circuit, wherein the power management circuit is configured as described above.
[0025] This utility model proposes a power management circuit and a power supply. The power management circuit is connected to a power supply module and a load. The power management circuit includes a first switching transistor, a current direction detection module, and a line switching module. The drain of the first switching transistor serves as the positive terminal of the power management circuit and is connected to the power supply module. The source of the first switching transistor is connected to the load. The detection terminal of the current direction detection module is located on the line connecting the output terminal of the first switching transistor and the load. The output terminal of the current direction detection module is connected to the control terminal of the line switching module. The moving connection terminal of the line switching module is connected to the gate of the first switching transistor. The first stationary connection terminal of the line switching module is grounded, and the second stationary connection terminal of the line switching module is connected to the source of the first switching transistor. The current direction detection module is used to detect the current direction on the line to obtain a detection result and send a control signal corresponding to the detection result to the line switching module. The line switching module is used to receive the control signal sent by the current direction detection module and connect the moving connection terminal to the first stationary connection terminal or the second stationary connection terminal according to the control signal. A current direction detection module is set up to detect backflow, and the connection status of the line switching module is adjusted based on the detection results. When the moving connection terminal is connected to the first stationary connection terminal, the first switch is turned on, and when the moving connection terminal is connected to the second stationary connection terminal, the first switch is turned off. Thus, the control of the state of the first switch based on the current direction is realized. When backflow occurs, the current can be prevented from flowing back to the power supply module by controlling the state of the first switch. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0027] Figure 1 This is a functional block diagram of an embodiment of the power management circuit of this utility model;
[0028] Figure 2 The power management circuit of this utility model is applied in Figure 1 Circuit structure diagram in the embodiment.
[0029] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.
[0030] Explanation of icon numbers:
[0031] label name label name 100 Current direction detection module R1~R3 First resistor ~ Third resistor 200 Line switching module Q1~Q2 First switching transistor ~ Second switching transistor 210 Signal determination unit Z1~Z2 First Zener diode ~ Second Zener diode 220 Switching unit K1 relay 300 Power supply module C1 First capacitor 400 load S1 comparator 500 Reverse connection protection module Detailed Implementation
[0032] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0034] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0035] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.
[0036] This utility model provides a power management circuit for use in power supplies. Please refer to [link / reference]. Figure 1 , Figure 1 This is a functional block diagram of an embodiment of the power management circuit of this utility model. In this embodiment, the power management circuit is connected to the power supply module 300 and the load 400. The power management circuit includes a first switching transistor Q1, a current direction detection module 100, and a line switching module 200. The drain of the first switching transistor Q1 serves as the positive terminal of the power management circuit and is connected to the power supply module 300. The source of the first switching transistor Q1 is connected to the load 400. The detection terminal of the current direction detection module 100 is located on the line connecting the output terminal of the first switching transistor Q1 and the load 400. The output terminal of the current direction detection module 100 is connected to the control terminal of the line switching module 200. The moving connection terminal of the line switching module 200 is connected to the gate of the first switching transistor Q1. The first stationary connection terminal of the line switching module 200 is grounded, and the second stationary connection terminal of the line switching module 200 is connected to the source of the first switching transistor Q1.
[0037] The current direction detection module 100 is used to detect the current direction on the line to obtain the detection result, and send the control signal corresponding to the detection result to the line switching module 200.
[0038] The line switching module 200 is used to receive the control signal sent by the current direction detection module 100, and connect the moving connection terminal to the first static connection terminal or the second static connection terminal according to the control signal.
[0039] The current direction detection module 100 is used to detect the current direction on the line. Under normal circumstances, the voltage output by the power supply module 300 supplies power to the load 400 through the first switch Q1, and the current direction is from the power supply module 300 to the first switch Q1 and then to the load 400. When reverse current occurs, the current direction is from the load 400 to the first switch Q1 and then to the power supply module 300. Therefore, by setting the detection terminal of the current direction detection module 100 on the line connected to the output terminal of the first switch Q1 and the load 400, it is possible to accurately detect whether reverse current has occurred. The current direction detection module 100 obtains the detection result based on the detection and sends the detection result to the line switching module 200.
[0040] The line switching module 200 includes a dynamic connection terminal and two static connection terminals. The dynamic connection terminal is not connected to the two static connection terminals simultaneously. In this embodiment, the first switching transistor Q1 is a PMOS transistor. When the dynamic connection terminal is connected to the first static connection terminal, the gate of the first switching transistor Q1 is grounded through the line switching module 200. At this time, the gate-source voltage of the first switching transistor Q1 meets the threshold voltage, the first switching transistor Q1 is turned on, and the power supply module 300 can supply power to the load 400. When the dynamic connection terminal is connected to the second static connection terminal, the gate of the first switching transistor Q1 is connected to the source of the first switching transistor Q1 through the line switching module 200. At this time, the gate-source voltage of the first switching transistor Q1 does not meet the threshold voltage, the first switching transistor Q1 is turned off, the power supply module 300 cannot supply power to the load 400, and at the same time, current cannot flow back to the power supply module 300.
[0041] As can be seen from the above principle, when the current direction detection module 100 detects that the current direction is from the power supply module 300 to the load 400, the moving connection terminal of the line switching module 200 will be connected to the first stationary connection terminal to turn on the first switch Q1; while when the current direction detection module 100 detects that the current direction is from the load 400 to the power supply module 300, the moving connection terminal of the line switching module 200 will be connected to the second stationary connection terminal to turn off the first switch Q1, thereby preventing backflow.
[0042] This embodiment uses a current direction detection module 100 to detect backflow and adjusts the connection state of the line switching module 200 based on the detection results. When the moving connection terminal is connected to the first stationary connection terminal, the first switch Q1 is turned on, and when the moving connection terminal is connected to the second stationary connection terminal, the first switch Q1 is turned off. Thus, the control of the state of the first switch Q1 based on the current direction is realized. When backflow occurs, the current can be prevented from flowing back to the power supply module 300 by controlling the state of the first switch Q1.
[0043] Furthermore, the current direction detection module 100 includes a first resistor R1, a second resistor R2, and a comparator S1; wherein:
[0044] The first resistor R1 is connected in series in the line connecting the output of the first switch Q1 to the load 400. The non-inverting input of the comparator S1 is connected to the end of the first resistor R1 closest to the load 400, and the inverting input of the comparator S1 is connected to the end of the first resistor R1 closest to the first switch Q1. The output of the comparator S1 is connected to the control terminal of the line switching module 200, and the output of the comparator S1 is also connected to the power supply through the second resistor R2.
[0045] The first resistor R1 is connected in series in the line connecting the output terminal of the first switching transistor Q1 to the load 400. Therefore, a voltage drop occurs when the voltage across the first resistor R1, and the voltage across the first resistor R1 also changes based on the direction of the current in the line. Specifically, when the current flows from the power supply module 300 to the load 400, the current flows from the end of the first resistor R1 closest to the first switching transistor Q1 (first end) to the end of the first resistor R1 closest to the load 400 (second end). At this time, the voltage at the first end of the first resistor R1 is greater than the voltage at the second end. When the current flows from the load 400 to the power supply module 300, the current flows from the second end of the first resistor R1 to the first end. At this time, the voltage at the second end of the first resistor R1 is greater than the voltage at the first end. It should be noted that since the first resistor R1 is connected in series in the line connecting the output terminal of the first switch Q1 and the load 400, a voltage drop is generated. Therefore, in order to minimize the impact on the power supply, the resistance value of the first resistor R1 can be set to be relatively small, thereby reducing the voltage drop of the first resistor R1. The resistance value of the first resistor R1 can be set based on the actual circuit, such as 0.1 Ohm.
[0046] Therefore, the magnitude of the voltage across the first resistor R1 can reflect the direction of the current in the circuit. Furthermore, in this embodiment, a comparator S1 is also provided. The two input terminals of the comparator S1 are connected to the two ends of the first resistor R1, respectively. Therefore, the output of the comparator S1 can indicate the magnitude of the voltage across the first resistor R1, that is, it can indicate the direction of the current in the circuit. Specifically, when the current flows from the power supply module 300 to the load 400, the voltage at the first terminal of the first resistor R1 is greater than the voltage at the second terminal, the voltage at the inverting input terminal of the comparator S1 is greater than the voltage at the non-inverting input terminal, and the comparator S1 outputs a low level. When the current flows from the load 400 to the power supply module 300, the voltage at the first terminal of the first resistor R1 is less than the voltage at the second terminal, the voltage at the inverting input terminal of the comparator S1 is less than the voltage at the non-inverting input terminal, and the comparator S1 outputs a high level. That is, when the comparator S1 outputs a low level, it indicates that the current direction is normal; when the comparator S1 outputs a high level, it indicates that the current is flowing backwards.
[0047] The second resistor R2 is a pull-up resistor, used to clamp the output of comparator S1 to a high level when comparator S1 does not output a low level.
[0048] Further, the line switching module 200 includes a signal determination unit 210 and a switching unit 220; the control terminal of the signal determination unit 210 is connected to the output terminal of the current direction detection module 100, the output terminal of the signal determination unit 210 is connected to the control terminal of the switching unit 220, the moving connection terminal of the switching unit 220 is connected to the gate of the first switching transistor Q1, the first stationary connection terminal of the switching unit 220 is grounded, and the second stationary connection terminal of the switching unit 220 is connected to the source of the first switching transistor Q1; wherein:
[0049] The signal determination unit 210 is used to receive the control signal sent by the current direction detection module 100 and output a switching signal corresponding to the control signal to the switching unit 220.
[0050] The switching unit 220 is used to connect the moving connection end to the first static connection end or the second static connection end according to the switching signal.
[0051] The signal determination unit 210 determines the state that the switching unit 220 needs to be set according to the control signal sent by the current direction detection module 100. When the current direction detection module 100 detects that the current direction is from the power supply module 300 to the load 400, the moving connection terminal of the switching unit 220 will be connected to the first stationary connection terminal to turn on the first switch Q1. When the current direction detection module 100 detects that the current direction is from the load 400 to the power supply module 300, the moving connection terminal of the switching unit 220 will be connected to the second stationary connection terminal to turn off the first switch Q1 and realize backflow prevention.
[0052] Furthermore, the signal determination unit 210 includes a second switch Q2, wherein:
[0053] The gate of the second switch Q2 is connected to the output terminal of the current direction detection module 100, the source of the second switch Q2 is grounded, and the drain of the second switch Q2 is connected to the control terminal of the switching unit 220.
[0054] In this embodiment, the second switch Q2 is an NMOS transistor as an example for illustration.
[0055] When the current direction detection module 100 outputs a high level, the gate of the second switch Q2 is at a high level and the source of the second switch Q2 is grounded. Therefore, the gate-source voltage of the second switch Q2 meets the threshold voltage of the second switch Q2, and the second switch Q2 is turned on.
[0056] When the current direction detection module 100 outputs a low level, the gate of the second switch Q2 is at a low level and the source of the second switch Q2 is grounded. Therefore, the gate-source voltage of the second switch Q2 does not meet the threshold voltage of the second switch Q2, and the second switch Q2 is turned off.
[0057] It is understandable that when the second switch Q2 is turned on, the switching unit 220 can be grounded through the second switch Q2, while when the second switch Q2 is turned off, the switching unit 220 cannot be grounded through the second switch Q2. Therefore, the turning on and off of the second switch Q2 can output different signals to the switching unit 220 to adjust the connection state of the switching unit 220.
[0058] Furthermore, the switching unit 220 includes a relay K1 and a first Zener diode Z1; wherein:
[0059] The first end of the coil of the relay K1 is connected to the power supply, and the first end of the coil of the relay K1 is also connected to the negative terminal of the first Zener diode Z1. The positive terminal of the first Zener diode Z1 is connected to the second end of the coil of the relay K1, and the second end of the coil of the relay K1 is also connected to the output terminal of the signal determination unit 210.
[0060] The first contact of the relay K1 is connected to the gate of the first switching transistor Q1, the second contact of the relay K1 is grounded, and the third contact of the relay K1 is connected to the source of the first switching transistor Q1; wherein, the first contact and the second contact form a normally closed contact, and the first contact and the third contact form a normally open contact.
[0061] When the second terminal of the coil of relay K1 is grounded, the coil of relay K1 is energized, the contacts of relay K1 are activated, the normally closed contact is opened, and the normally open contact is closed, that is, the first contact and the third contact are closed. At this time, the gate of the first switching transistor Q1 is connected to the source of the first switching transistor Q1 through the first contact and the third contact, and the first switching transistor Q1 is turned off.
[0062] When the second terminal of the coil of relay K1 is not grounded, the coil of relay K1 is not energized, the contacts of relay K1 are restored, the normally closed contacts are closed, and the normally open contacts are open, that is, the first contact and the second contact are closed. At this time, the gate of the first switching transistor Q1 is grounded through the first contact and the second contact, and the first switching transistor Q1 is turned on.
[0063] The first Zener diode Z1 is used to protect the coil of relay K1.
[0064] Furthermore, the power management circuit also includes a reverse connection protection module 500, which is connected between the gate and source of the first switching transistor Q1, wherein:
[0065] The reverse connection protection module 500 is used to turn off the first switch Q1 when the power supply module 300 is reverse connected.
[0066] Understandably, during normal connection, the voltage pin of the power supply module 300 outputs voltage to the load 400, and the ground pin is grounded; however, in the event of reverse connection, the voltage pin of the power supply module 300 is grounded, and the ground pin outputs voltage; in this case, it is easy to damage the circuit and the load 400; therefore, in this embodiment, a reverse connection protection module 500 is provided to control the first switch Q1 to turn off when the power supply module 300 is reverse connected, thereby avoiding the impact of reverse connection on the subsequent circuit.
[0067] Furthermore, the reverse connection protection module 500 includes a second Zener diode Z2, a first capacitor C1, and a third resistor R3; wherein:
[0068] The negative terminal of the second Zener diode Z2 is connected to the source terminal of the first switching transistor Q1, the positive terminal of the second Zener diode Z2 is grounded through the third resistor R3, and the first capacitor C1 is connected in parallel with the second Zener diode Z2.
[0069] The first static connection terminal of the line switching module 200 is grounded through the third resistor R3.
[0070] The second Zener diode Z2 is connected in parallel with the first capacitor C1 to prevent breakdown between the gate and source of the first switching transistor Q1.
[0071] The principle of the reverse connection protection module 500 is explained under the condition that the current direction is normal:
[0072] When the power supply module 300 is connected normally, the gate of the first switching transistor Q1 is grounded through the line switching module 200 and the third resistor R3. The voltage of the power supply module 300 reaches the source of the first switching transistor Q1 through the body diode of the first switching transistor Q1. The gate-source voltage of the first switching transistor Q1 meets the threshold voltage, and the first switching transistor Q1 is turned on.
[0073] When the power supply module 300 is reverse-connected, the gate of the first switching transistor Q1 is connected to the voltage pin of the power supply module 300 through the line switching module 200 and the third resistor R3. The gate-source voltage of the first switching transistor Q1 does not meet the threshold voltage, so the first switching transistor Q1 is turned off, thus achieving the reverse connection protection function.
[0074] It should be noted that when the power supply module 300 is reversed, the source of the second switching transistor Q2 is supplied with the voltage of the power supply module 300. At this time, the coil of the relay K1 is also not energized and remains in its initial state, that is, the first contact and the second contact are closed.
[0075] It should be noted that the second contact of relay K1 needs to be grounded. In practical applications, the second contact of relay K1 can be grounded through the third resistor R3.
[0076] The overall principles of this application are explained below:
[0077] When the power supply module 300 is properly connected and the current flows from the power supply module 300 to the load 400:
[0078] The voltage at the first terminal of the first resistor R1 is greater than the voltage at the second terminal. The voltage at the inverting input terminal of comparator S1 is greater than the voltage at the non-inverting input terminal. Comparator S1 outputs a low level. The gate-source voltage of the second switch Q2 does not meet the threshold voltage of the second switch Q2, so the second switch Q2 is turned off. The second terminal of the coil of relay K1 is not grounded, the coil of relay K1 is not energized, the contacts of relay K1 are restored, the normally closed contact is closed, and the normally open contact is open, that is, the first contact and the second contact are closed. At this time, the gate of the first switch Q1 is grounded through the first contact and the second contact, and the first switch Q1 is turned on. The power supply module 300 normally supplies power to the load 400.
[0079] When the power supply module 300 is properly connected and the current flows from the load 400 to the power supply module 300:
[0080] The voltage across the first terminal of the first resistor R1 is less than the voltage across the second terminal. The voltage across the inverting input terminal of comparator S1 is less than the voltage across the non-inverting input terminal, so comparator S1 outputs a high level. The gate-source voltage of the second switch Q2 meets the threshold voltage of the second switch Q2, so the second switch Q2 is turned on. The second terminal of the coil of relay K1 is grounded, the coil of relay K1 is energized, and the contacts of relay K1 are activated. The normally closed contact opens, and the normally open contact closes, that is, the first contact and the third contact are closed. At this time, the gate of the first switch Q1 is connected to the source of the first switch Q1 through the first contact and the third contact, so the first switch Q1 is turned off, preventing current backflow.
[0081] When the power supply module 300 is reverse-connected and the current flows from the power supply module 300 to the load 400:
[0082] The voltage at the first terminal of the first resistor R1 is greater than the voltage at the second terminal. The voltage at the inverting input terminal of comparator S1 is greater than the voltage at the non-inverting input terminal. Comparator S1 outputs a low level, the second switch Q2 is turned off, the first and second contacts of relay K1 are closed, the gate of the first switch Q1 is connected to the voltage pin of the power supply module 300 through the first contact, the second contact, and the third resistor R3, the positive voltage of the second Zener diode Z2 is greater than the negative voltage, the gate voltage of the first switch Q1 is greater than the source voltage, and the first switch Q1 is turned off; thus achieving the reverse connection protection function.
[0083] When the power supply module 300 is reverse-connected and the current flows from the load 400 to the power supply module 300:
[0084] The voltage at the first terminal of the first resistor R1 is less than the voltage at the second terminal, the voltage at the inverting input terminal of comparator S1 is less than the voltage at the non-inverting input terminal, comparator S1 outputs a high level, the second switch Q2 is turned on, the first and third contacts of relay K1 are closed, the gate of the first switch Q1 is connected to the source through the first and third contacts, the gate voltage of the first switch Q1 is equal to the source voltage, and the first switch Q1 is turned off; thus achieving the reverse connection protection function.
[0085] This utility model also protects a power supply, which includes a power supply module 300 and a power management circuit. The structure of the power management circuit can be referred to in the above embodiment, and will not be repeated here. Therefore, since the power supply in this embodiment adopts the technical solution of the above-described power management circuit, it has all the beneficial effects of the above-described power management circuit.
[0086] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element. The sequence numbers of the above-described embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0087] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.
Claims
1. A power management circuit, characterized in that, The power management circuit is connected to the power supply module and the load. The power management circuit includes a first switching transistor, a current direction detection module, and a line switching module. The drain of the first switching transistor serves as the positive terminal of the power management circuit and is connected to the power supply module. The source of the first switching transistor is connected to the load. The detection terminal of the current direction detection module is located on the line connecting the output terminal of the first switching transistor and the load. The output terminal of the current direction detection module is connected to the control terminal of the line switching module. The moving connection terminal of the line switching module is connected to the gate of the first switching transistor. The first stationary connection terminal of the line switching module is grounded, and the second stationary connection terminal of the line switching module is connected to the source of the first switching transistor. Wherein: The current direction detection module is used to detect the current direction on the line to obtain the detection result, and send the control signal corresponding to the detection result to the line switching module. The line switching module is used to receive the control signal sent by the current direction detection module, and connect the moving connection terminal to the first stationary connection terminal or the second stationary connection terminal according to the control signal.
2. The power management circuit as described in claim 1, characterized in that, The current direction detection module includes a first resistor, a second resistor, and a comparator; wherein: The first resistor is connected in series in the line connecting the output of the first switch to the load. The non-inverting input of the comparator is connected to the end of the first resistor closest to the load, and the inverting input of the comparator is connected to the end of the first resistor closest to the first switch. The output of the comparator is connected to the control terminal of the line switching module, and the output of the comparator is also connected to the power supply through the second resistor.
3. The power management circuit as described in claim 1, characterized in that, The line switching module includes a signal determination unit and a switching unit; the control terminal of the signal determination unit is connected to the output terminal of the current direction detection module, the output terminal of the signal determination unit is connected to the control terminal of the switching unit, the moving connection terminal of the switching unit is connected to the gate of the first switching transistor, the first stationary connection terminal of the switching unit is grounded, and the second stationary connection terminal of the switching unit is connected to the source of the first switching transistor; wherein: The signal determination unit is used to receive the control signal sent by the current direction detection module and output a switching signal corresponding to the control signal to the switching unit; The switching unit is used to connect the moving connection end to the first stationary connection end or the second stationary connection end according to the switching signal.
4. The power management circuit as described in claim 3, characterized in that, The signal determination unit includes a second switching transistor, wherein: The gate of the second switching transistor is connected to the output terminal of the current direction detection module, the source of the second switching transistor is grounded, and the drain of the second switching transistor is connected to the control terminal of the switching unit.
5. The power management circuit as described in claim 4, characterized in that, The second switch is an NMOS transistor.
6. The power management circuit as described in claim 3, characterized in that, The switching unit includes a relay and a first Zener diode; wherein: The first end of the relay coil is connected to the power supply, and the first end of the relay coil is also connected to the negative terminal of the first Zener diode. The positive terminal of the first Zener diode is connected to the second end of the relay coil, and the second end of the relay coil is also connected to the output terminal of the signal determination unit. The first contact of the relay is connected to the gate of the first switching transistor, the second contact of the relay is grounded, and the third contact of the relay is connected to the source of the first switching transistor; wherein, the first contact and the second contact form a normally closed contact, and the first contact and the third contact form a normally open contact.
7. The power management circuit as described in claim 1, characterized in that, The power management circuit further includes a reverse connection protection module, which is connected between the gate and source of the first switching transistor, wherein: The reverse connection protection module is used to turn off the first switch when the power supply module is reverse connected.
8. The power management circuit as described in claim 7, characterized in that, The reverse connection protection module includes a second Zener diode, a first capacitor, and a third resistor; wherein: The negative terminal of the second Zener diode is connected to the source terminal of the first switching transistor, the positive terminal of the second Zener diode is grounded through the third resistor, and the first capacitor is connected in parallel with the second Zener diode; The first static connection terminal of the line switching module is grounded through the third resistor.
9. The power management circuit as described in any one of claims 1 to 8, characterized in that, The first switching transistor is a PMOS transistor.
10. A power supply, characterized in that, The power supply includes a power supply module and a power management circuit as described in any one of claims 1 to 9.