Power supply automatic switching system

Abstract

The utility model provides a power supply automatic switching system, and belongs to the technical field of power supply management. The power supply switching circuit comprises a switching unit, a first input end, a second input end and a first output end, the first input end and the second input end are connected with the first output end through the switching unit, the first input end is connected with a first voltage, and the second input end is connected with a second voltage. By switching the first voltage and the second voltage, the technical problem that a vehicle-mounted positioning terminal, a communication terminal and the like in an automobile are powered off and cannot work when the power supply of the whole automobile is powered off accidentally is solved; and the standby power supply voltage is provided through the second voltage, so that the standby power supply voltage can be switched through the power supply switching circuit even when the power supply of the whole vehicle is accidentally powered down, and then the vehicle-mounted positioning terminal, the communication terminal and the like in the vehicle can be maintained to be powered off and work normally, and the situation that vehicle information cannot be uploaded and monitored in real time, and data loss is caused is prevented.

Description

Technical Field

[0001] The present application belongs to the technical field of power management, and specifically relates to an automatic power switching system. Background Art

[0002] The on-board positioning and communication terminals installed in the later stage of the car are usually connected to the power supply of the whole vehicle. However, when the power supply of the whole vehicle is accidentally cut off, the on-board positioning and communication terminals are also powered off and cannot work, which makes it impossible to upload and monitor vehicle information in real time, resulting in data loss. Summary of the Invention

[0003] The present application provides an automatic power switching system, which solves the technical problem that when the power of the entire vehicle is accidentally cut off, the vehicle-mounted positioning, communication terminals, etc. in the car are also cut off and cannot work.

[0004] The present application provides an automatic power switching system. The automatic power switching system includes a power switching circuit, the power switching circuit including a switching unit, a first input terminal, a second input terminal, and a first output terminal. The first input terminal and the second input terminal are both connected to the first output terminal via the switching unit. The first input terminal is connected to a first voltage, and the second input terminal is connected to a second voltage.

[0005] In some embodiments, the first output terminal is configured to output the first voltage or the second voltage based on a numerical relationship between the first voltage and the second voltage.

[0006] In some embodiments, when the first voltage is greater than the second voltage, the first output terminal is configured to output the first voltage; when the first voltage is less than the second voltage, the first output terminal is configured to output the second voltage.

[0007] In some embodiments, the switching unit includes a first conductive device and a second conductive device, the first conductive device includes a first end and a second end, the first end is configured to be connected to the first voltage, and the second end is configured to be connected to the first output end; the second conductive device includes a third end, a fourth end, and a fifth end, the third end is configured to be connected to the second voltage, the fourth end is configured to be connected to the first voltage, and the fifth end is configured to be connected to the first output end.

[0008] In some embodiments, the first conductive device includes a first diode, an anode of the first diode is configured as the first end, and a cathode of the first diode is configured as the second end.

[0009] In some embodiments, the second conductive device includes a MOS transistor, the drain of the MOS transistor is configured as the third terminal, the gate of the MOS transistor is configured as the fourth terminal, and the source of the MOS transistor is configured as the fifth terminal.

[0010] In some embodiments, the automatic power switching system further includes a first voltage conversion circuit, the first voltage conversion circuit including a third input terminal and a second output terminal, the third input terminal is configured to input a third voltage, and the second output terminal is configured to output the first voltage.

[0011] In some embodiments, the first voltage conversion circuit includes a transient voltage protection device, an anti-reverse polarity device, a common-mode suppression device, and a first DC conversion device. The transient voltage protection device includes a sixth terminal and a seventh terminal, the anti-reverse polarity device includes an eighth terminal and a ninth terminal, the common-mode suppression device includes a tenth terminal, an eleventh terminal, a twelfth terminal, and a thirteenth terminal. The first DC conversion device includes a fourteenth terminal and a fifteenth terminal. The sixth terminal is configured to be connected to the third input terminal and the tenth terminal, respectively. The seventh terminal is configured to be connected to the eleventh terminal. The twelfth terminal is configured to be connected to the eighth terminal. The thirteenth terminal is configured to be connected to the ninth terminal and the fourteenth terminal, respectively. The fifteenth terminal is configured to be connected to the second output terminal.

[0012] In some embodiments, the automatic power switching system further includes a second voltage conversion circuit, the second voltage conversion circuit including a fourth input terminal and a third output terminal, the fourth input terminal is configured to input a fourth voltage, and the third output terminal is configured to output a second voltage.

[0013] In some embodiments, the second voltage conversion circuit includes a second DC conversion device, the second DC conversion device includes a sixteenth terminal and a seventeenth terminal, the sixteenth terminal is configured to be connected to the fourth input terminal, and the seventeenth terminal is configured to be connected to the third output terminal.

[0014] The beneficial effect of the present application is that the present application provides an automatic power switching system, wherein the power switching circuit includes a switching unit, a first input terminal, a second input terminal, and a first output terminal, wherein the first input terminal and the second input terminal are both connected to the first output terminal via the switching unit, the first input terminal is connected to a first voltage, and the second input terminal is connected to a second voltage. By switching between the first voltage and the second voltage, the technical problem that when the power supply of the entire vehicle is accidentally cut off, the vehicle-mounted positioning, communication terminal, etc. in the vehicle are also cut off and cannot work is solved; and the second voltage is used to provide a backup power supply voltage, so that when the power supply of the entire vehicle is accidentally cut off, the backup power supply voltage can be switched through the power switching circuit even if the power supply is cut off, thereby maintaining the vehicle-mounted positioning, communication terminal, etc. in the vehicle to work normally even if the power is cut off, preventing the vehicle information from being unable to be uploaded and monitored in real time, resulting in data loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 A circuit diagram of a power switching circuit provided in an embodiment of the present application;

[0017] Figure 2 A circuit diagram of a first voltage conversion circuit provided in an embodiment of the present application;

[0018] Figure 3 This is a circuit diagram of the second voltage conversion circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0020] This application provides an automatic power switching system, which is described in detail below. It should be noted that the order in which the following embodiments are described does not limit the preferred order of the embodiments of this application. Furthermore, in the following embodiments, the description of each embodiment has its own emphasis. For portions not described in detail in one embodiment, please refer to the relevant descriptions of other embodiments.

[0021] With the increasing adoption of smart cars, onboard positioning and communication terminals have become standard features for household vehicles. However, in the commercial vehicle sector, especially for older models, their penetration remains low. In the era of big data, transportation companies urgently need to monitor vehicle location and centrally manage transportation information. However, due to the large fleet size and cost constraints, mass-produced fleet upgrades are virtually impossible. This is why retrofitted onboard positioning and communication terminals have emerged. Currently, most onboard positioning and communication terminals lack battery backup capabilities, preventing real-time upload and monitoring of vehicle information in the event of a vehicle failure or power outage. This technology aims to address the data disconnection issue caused by external power outages in onboard positioning and communication terminals. While some solutions with battery backup are currently available, the switching process between external and backup power requires software control, significantly increasing hardware, development, and maintenance costs, as well as the switching time between internal and external power. Furthermore, the complex circuitry also challenges stability.

[0022] Traditional software implementation solutions require sampling, comparison, and execution, which significantly impacts the switching speed of external and internal power supplies. Switching speed is a crucial factor in maintaining the normal operation of the product. Furthermore, the complex software implementation process poses challenges to the overall stability of the product. Furthermore, from a cost perspective, software solutions require switching devices such as MUCs as drive units, leading to material and software development costs that are far higher than those of pure hardware solutions.

[0023] Furthermore, this application designs an automatic power switching system based on a pure hardware solution. Through pure hardware circuit design, the power switching process is simplified, the circuit is simpler, the switching speed is improved, and the technical problem that the power switching process needs to be coordinated with software control, which increases the product's hardware cost, development cost, maintenance cost and power switching time, is solved, thereby achieving the purpose of reducing product hardware cost, development cost, maintenance cost, improving switching speed and product stability.

[0024] like Figure 1 As shown, Figure 1 This is a circuit diagram of a power switching circuit provided in an embodiment of the present application. The present application provides an automatic power switching system. The automatic power switching system includes: a power switching circuit, the power switching circuit including a switching unit, a first input terminal, a second input terminal, and a first output terminal. The first input terminal and the second input terminal are both connected to the first output terminal via the switching unit. The first input terminal is connected to a first voltage, and the second input terminal is connected to a second voltage.

[0025] Specifically, in this application, the first voltage is derived from an external power source, and the second voltage is derived from a backup battery. The external power source refers to the vehicle's power supply, citing 24V as an example in this application; the backup power source refers to the product's internal lithium battery, citing 3.7V as an example. The first or second voltage is supplied to the corresponding load via the first output terminal, such as the vehicle's onboard positioning system or communication terminal.

[0026] In some embodiments, the first output terminal is configured to output the first voltage or the second voltage based on a numerical relationship between the first voltage and the second voltage. Specifically, the first output terminal is configured to output the first voltage or the second voltage, that is, the first output terminal is configured to output the first voltage or the second voltage based on whether the first voltage is interrupted.

[0027] In some embodiments, when the first voltage is greater than the second voltage, the first output terminal is configured to output the first voltage; when the first voltage is less than the second voltage, the first output terminal is configured to output the second voltage. Specifically, when the first voltage is not interrupted, the first output terminal is configured to output the first voltage; when the first voltage is interrupted, the first output terminal is configured to output the second voltage.

[0028] The first voltage interruption means that the power supply providing the first voltage is disconnected, that is, the power supply providing the first voltage cannot supply power, and the power supply cannot provide current, resulting in that the components in the circuit cannot work normally.

[0029] In some embodiments, the switching unit includes a first conductive device and a second conductive device, the first conductive device includes a first end and a second end, the first end is configured to be connected to the first voltage, and the second end is configured to be connected to the first output end; the second conductive device includes a third end, a fourth end, and a fifth end, the third end is configured to be connected to the second voltage, the fourth end is configured to be connected to the first voltage, and the fifth end is configured to be connected to the first output end.

[0030] That is to say, the power switching circuit includes a first conductive device, a second conductive device, a first input terminal, a second input terminal, and a first output terminal. The first input terminal is connected to the first output terminal via the first conductive device and the second conductive device respectively, and the second input terminal is connected to the first output terminal via the second conductive device. The first input terminal is connected to a first voltage, and the second input terminal is connected to a second voltage.

[0031] In some embodiments, the first conductive device includes a first diode, the anode of the first diode is configured as the first end, and the cathode of the first diode is configured as the second end, specifically the diode D1 in the figure.

[0032] In some embodiments, the second conducting device includes a MOS transistor, the drain of the MOS transistor is configured as the third terminal, the gate of the MOS transistor is configured as the fourth terminal, and the source of the MOS transistor is configured as the fifth terminal, specifically the MOS transistor Q1 in the figure.

[0033] Exemplarily, the power switching circuit includes an electrolytic capacitor C1, a capacitor C2, a resistor R1, a MOS transistor Q1, an electrolytic capacitor C3, a bidirectional TVS diode D2, and a diode D1. The positive electrode of the electrolytic capacitor C1 is respectively connected to the first input terminal, one end of the capacitor C2, the positive electrode of the diode D1, one end of the resistor R1, and the gate of the MOS transistor Q1. The negative electrode of the electrolytic capacitor C1 is respectively connected to the other end of the capacitor C2 and ground, and the other end of the resistor R1 is grounded. The drain of the MOS transistor Q1 is connected to the second input terminal. The source of the MOS transistor Q1 is respectively connected to the first output terminal, the negative electrode of the diode D1, the positive electrode of the electrolytic capacitor C3, and one end of the bidirectional TVS diode D2. The negative electrode of the electrolytic capacitor C3 and the other end of the bidirectional TVS diode D2 are grounded. In the figure, the first input terminal refers to the VCC_5V terminal, the second input terminal refers to the VBAT_4.5V terminal, and the first output terminal refers to the VCC_OUT terminal, that is, 5V is configured as the first voltage and 4.5V is configured as the second voltage.

[0034] When the power supply corresponding to the first voltage is supplying power normally, the power supply corresponding to the first voltage should be cut off; the first voltage is provided by an external power supply, and the second voltage is provided by a lithium battery power supply; and when the external power supply is disconnected, the lithium battery power supply should be connected; MOS tube Q1 is a P-MOS field effect tube. When the external power supply is connected, the gate voltage of the P-MOS is approximately 5V, and the P-MOS is cut off. Since D1 is a low conduction voltage diode with a conduction voltage of approximately 0.4V, the source voltage of the P-MOS is approximately 4.6V, the drain voltage is 4.5V, and the body diode is cut off. Therefore, its source and drain are equivalent to being disconnected. The external power supply is directly loaded to the load end through the diode D1. At this time, only the external power supply supplies power to the load. When the external power supply is disconnected, the lithium battery power is directly turned on through the body diode of the P-MOS and output to the load. At this time, D1 prevents the lithium battery current from flowing back to the external power supply. In addition, C1 and C3 are energy storage capacitors, which can ensure that the circuit can still provide a stable output voltage to the load under large load fluctuations. D2 provides transient voltage protection for subsequent loads. Because the P-MOS device is a low on-resistance device with an on-resistance of approximately 40mΩ, its conduction loss can be minimized.

[0035] Among them, the parameters of each component in the figure are explained with examples. Taking capacitor C1 as an example, 220uF / 10V means that the capacitance of a capacitor is 220 microfarads (220uF) and its rated voltage is 10 volts (10V). The explanations of other capacitor parameters are similar; taking resistor R1 as an example, 1M / 1% means that the resistance of a resistor is 1 megohm (1MΩ) and its resistance accuracy is 1%. The explanations of other resistor parameters are similar.

[0036] In view of this, the present application provides a power automatic switching system, wherein the power switching circuit includes a switching unit, a first input terminal, a second input terminal, and a first output terminal, wherein the first input terminal and the second input terminal are both connected to the first output terminal via the switching unit, the first input terminal is connected to a first voltage, and the second input terminal is connected to a second voltage. By switching between the first voltage and the second voltage, the technical problem that when the power supply of the entire vehicle is accidentally cut off, the vehicle-mounted positioning, communication terminal, etc. in the vehicle are also cut off and cannot work is solved; and the backup power supply voltage is provided by the second voltage, so that when the power supply of the entire vehicle is accidentally cut off, the backup power supply voltage can be switched even by the power switching circuit, thereby maintaining the vehicle-mounted positioning, communication terminal, etc. in the vehicle to work normally even when the power supply is cut off, preventing the vehicle information from being unable to be uploaded and monitored in real time, resulting in data loss. In addition, through pure hardware circuit design, the power switching process is simplified, the circuit is simpler, the switching speed is improved, and the technical problem that the power switching process needs to be coordinated with software control, which increases the hardware cost, development cost, maintenance cost of the product and the power switching time is solved. Furthermore, based on a purely hardware design, we abandoned the design approach of achieving automatic switching through the judgment of logic chips or logic circuits, and chose a design approach with the least number of components, all of which are basic components. Fewer components will result in fewer fault conditions in the entire circuit, which is beneficial for subsequent maintenance of the product. Furthermore, basic electronic components will make the entire circuit analysis simpler and less costly, while also having lower static power consumption.

[0037] like Figure 2 As shown, Figure 2 This is a circuit diagram of a first voltage conversion circuit provided in an embodiment of the present application. In some embodiments, the automatic power switching system further includes a first voltage conversion circuit, the first voltage conversion circuit including a third input terminal and a second output terminal, the third input terminal being configured to input a third voltage, and the second output terminal being configured to output the first voltage.

[0038] In some embodiments, the first voltage conversion circuit includes a transient voltage protection device, an anti-reverse polarity device, a common-mode suppression device, and a first DC conversion device. The transient voltage protection device includes a sixth terminal and a seventh terminal, the anti-reverse polarity device includes an eighth terminal and a ninth terminal, the common-mode suppression device includes a tenth terminal, an eleventh terminal, a twelfth terminal, and a thirteenth terminal. The first DC conversion device includes a fourteenth terminal and a fifteenth terminal. The sixth terminal is configured to be connected to the third input terminal and the tenth terminal, respectively. The seventh terminal is configured to be connected to the eleventh terminal. The twelfth terminal is configured to be connected to the eighth terminal. The thirteenth terminal is configured to be connected to the ninth terminal and the fourteenth terminal, respectively. The fifteenth terminal is configured to be connected to the second output terminal.

[0039] Exemplarily, the transient voltage protection device includes a bidirectional TVS diode, one end of the bidirectional TVS diode is configured as the sixth end, and the other end of the bidirectional TVS diode is configured as the seventh end, the anti-reverse polarity device includes a second diode, the positive pole of the second diode is configured as the eighth end, and the negative pole of the second diode is configured as the ninth end, the common-mode suppression device includes a transformer, the first input pin of the transformer is configured as the tenth end, the second input pin of the transformer is configured as the eleventh end, the first output pin of the transformer is configured as the twelfth end, and the second output pin of the transformer is configured as the thirteenth end, the first DC conversion device includes a DC-DC chip U1, the input pin of the DC-DC chip U1 is configured as the fourteenth end, that is, the IN pin of the DC-DC chip U1 is configured as the fourteenth end, and the output feedback pin of the DC-DC chip U1 is configured as the fifteenth end, that is, the FB pin of the DC-DC chip U1 is configured as the fifteenth end.

[0040] Exemplarily, the first transformer circuit includes a fuse F1, a bidirectional TVS diode D3, a capacitor C4, a diode D4, a capacitor C5, a mutual inductor T1, a resistor R2, a resistor R3, a resistor R4, a DC-DC chip U1, a capacitor C6, a diode D5, a resistor R5, a resistor R6, a capacitor C7, a capacitor C8, a capacitor C9, a diode D3, and an inductor L1. One end of the fuse is connected to an external power supply, and the other end of the fuse is respectively connected to one end of the bidirectional TVS diode D3 and a first input pin of the mutual inductor T1. The other end of the bidirectional TVS diode D3 is respectively grounded and connected to the second input pin of the mutual inductor T1. The first output pin of the mutual inductor T1 is respectively connected to one end of the capacitor C4 and the positive electrode of the diode D4. The second output pin of the mutual inductor T1 is respectively connected to the other end of the capacitor C4, the other end of the capacitor C5, and ground. The negative electrode of the diode D4 is respectively connected to one end of the capacitor C5, one end of the resistor R2, and the IN pin of the DC-DC chip. The other end is respectively connected to one end of the resistor R4 and the EN pin of the DC-DC chip. The other end of the resistor R4 is respectively connected to one end of the resistor R3 and to ground. The other end of the resistor R3 is connected to the PS pin of the DC-DC chip. The GND pin of the DC-DC chip is grounded. The EP pin of the DC-DC chip is respectively grounded and connected to the positive electrode of the diode D5. The negative electrode of the diode D5 is respectively connected to the LX pin of the DC-DC chip, one end of the capacitor C6, and one end of the inductor L1. The other end of the capacitor C6 is connected to the BS pin of the DC-DC chip. The FB pin of the DC-DC chip is respectively connected to one end of the resistor R5, one end of the resistor R6, and one end of the capacitor C7. The other end of the inductor L1 is respectively connected to the other end of the resistor R5, the other end of the capacitor C7, one end of the capacitor C8, one end of the capacitor C9, and the positive electrode of the diode D3. The other end of the resistor R6 is grounded. The other end of the capacitor C8 and the other end of the capacitor C9 are both grounded. The negative electrode of the diode D3 is connected to the second output end. The third input terminal is VBAT_24V, the second output terminal is VCC_5V, and the DC-DC chip U1 is a step-down DC-DC chip. That is, 24V is configured as the third voltage.

[0041] In this application, the backup power supply typically uses a lithium battery, whose voltage is generally around 3.8V. The external vehicle power supply voltage is generally 24V. Due to the actual load requirements, this application sets the system output voltage to around 5V, which requires stepping down the 24V external power supply to 5V. D3 implements transient voltage protection, D4 is a reverse polarity protection circuit, T1 is a common-mode suppression transformer, and U1 is a DC-DC chip, which can be the SY8513. Its input voltage can reach up to 100V, ensuring stable operation of the subsequent circuits. Inductor L1 is a component within the DC-DC power supply topology and is a power inductor. The parameters of each component in the figure are explained with examples. For inductor L1, 33uH 1A indicates an inductor with an inductance of 33 microhenries (33uH) and a rated current of 1 ampere (1A). The explanations for other inductor parameters are similar.

[0042] In view of this, for automotive electronic products, interference is often coupled into the product through the vehicle wiring harness. Therefore, we have implemented transient voltage protection, common-mode interference suppression, anti-reverse polarity and overvoltage protection designs at the external power input interface. By protecting against the source of interference, we ensure that our core circuit - the automatic backup battery switching circuit - can operate stably and reliably for a long time.

[0043] like Figure 3 As shown, Figure 3 This is a circuit diagram of a second voltage conversion circuit provided in an embodiment of the present application. In some embodiments, the automatic power switching system further includes a second voltage conversion circuit, the second voltage conversion circuit including a fourth input terminal and a third output terminal, the fourth input terminal being configured to input a fourth voltage, and the third output terminal being configured to output a second voltage.

[0044] In some embodiments, the second voltage conversion circuit includes a second DC conversion device, which includes a sixteenth terminal and a seventeenth terminal. The sixteenth terminal is configured to be connected to the fourth input terminal, and the seventeenth terminal is configured to be connected to the third output terminal. Specifically, it is a DC-DC chip U2. The input pin of the DC-DC chip U2 is configured as the sixteenth terminal, that is, the IN pin of the DC-DC chip U2 is configured as the sixteenth terminal, and the output pin of the DC-DC chip U2 is configured as the seventeenth terminal, that is, the OUT pin of the DC-DC chip U2 is configured as the seventeenth terminal.

[0045] Exemplarily, the second voltage conversion circuit includes a capacitor C10, a resistor R7, an inductor L2, a DC-DC chip U2, a resistor R8, a resistor R9, a capacitor C11, and a capacitor C12. One end of the capacitor C10 is respectively connected to the fourth input terminal, one end of the inductor L2, one end of the resistor R7, and the IN pin of the DC-DC chip U2. The other end of the capacitor C10 is grounded. The other end of the inductor L2 is connected to the LX pin of the DC-DC chip U2. The other end of the resistor R7 is connected to the EN pin of the DC-DC chip U2. The OUT pin of the DC-DC chip U2 is respectively connected to one end of the resistor R8, one end of the capacitor C11, one end of the capacitor C12, and the third output terminal. The FB pin of the DC-DC chip U2 is respectively connected to the other end of the resistor R8, one end of the resistor R9, and the other end of the capacitor C11. The GND pin of the DC-DC chip U2 is grounded, and the other end of the resistor R9 and the other end of the capacitor C12 are both grounded. Wherein, the fourth input terminal refers to VBAT_3.7V, and the third output terminal refers to VBAT_4.5V. That is, 3.7V is configured as the fourth voltage.

[0046] In the second voltage conversion circuit, we need to boost the lithium battery voltage. The target voltage needs to be slightly lower than 5V. To ensure that when the first voltage is greater than the second voltage, the first output terminal is configured to output the first voltage; when the first voltage is not greater than the second voltage, the first output terminal is configured to output the second voltage. In this example, we set it to 4.5V. C10 and C12 are filter capacitors, and U2 is a DC-DC boost chip, which can be SY7072AABC.

[0047] Furthermore, the present application provides an automatic power switching system. The automatic power switching system includes a pure hardware circuit design that simplifies the power switching process, makes the circuit simpler, improves the switching speed, and solves the technical problem that the power switching process needs to be coordinated with software control, which increases the hardware cost, development cost, maintenance cost of the product and the power switching time. It avoids the traditional software implementation solution that needs to go through the sampling, comparison, and execution process, which greatly affects the switching speed of the external and internal power supplies. The switching speed is an important indicator for maintaining the normal operation of the product. In addition, the complex software implementation process also poses a challenge to the overall stability of the product. Furthermore, from a cost perspective, the software solution requires some switching devices such as MUC as a driving unit, and the material cost and software development cost are much higher than the pure hardware solution.

[0048] Based on a purely hardware design, we abandoned the design scheme that uses logic chips or logic circuits to achieve automatic switching. Instead, we chose a design scheme with the least number of components and all of them are basic components. Fewer components will result in fewer fault conditions in the entire circuit, which is beneficial for subsequent maintenance of the product. Furthermore, basic electronic components will make the entire circuit analysis simple and low-cost, while also having lower static power consumption.

[0049] In addition, key circuit components should be electronic devices with low internal resistance and low on-state voltage. The lithium battery used in the product is designed to provide emergency power in the event of an abnormal power outage. Due to product cost and volume requirements, the capacity of the lithium battery is limited. To increase the product's standby time when the external power supply is disconnected, it is necessary to reduce component loss in the hardware circuit, that is, to reduce static power consumption. Therefore, low on-state resistance or low internal resistance devices are used in the path through which the battery power flows.

[0050] For automotive electronic products, interference is often coupled into the product through the vehicle wiring harness. Therefore, we have implemented transient voltage protection, common-mode interference suppression, reverse polarity protection, and overvoltage protection at the external power input interface through the first transformer circuit. By protecting against the interference source, we ensure that our core circuit—the automatic backup battery switching circuit—operates stably and reliably for a long time.

[0051] The above is a detailed introduction to an automatic power switching system provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for general technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A power automatic switching system, characterized in that: include: A power switching circuit, comprising a switching unit, a first input terminal, a second input terminal, and a first output terminal. The first input terminal and the second input terminal are both connected to the first output terminal via the switching unit. The first input terminal is connected to a first voltage, The second input terminal is connected to a second voltage; The switching unit includes a first conductive device and a second conductive device, the first conductive device includes a first end and a second end, the first end is configured to be connected to the first voltage, and the second end is configured to be connected to the first output end; The second conductive device includes a third terminal, a fourth terminal, and a fifth terminal. The third terminal is configured to be connected to the second voltage, the fourth terminal is configured to be connected to the first voltage, and the fifth terminal is configured to be connected to the first output terminal.

2. The automatic power switching system according to claim 1, characterized in that: The first output terminal is configured to output a first voltage or a second voltage based on a numerical relationship between the first voltage and the second voltage.

3. The automatic power switching system according to claim 2, characterized in that: When the first voltage is greater than the second voltage, the first output terminal is configured to output the first voltage; When the first voltage is less than the second voltage, the first output terminal is configured to output the second voltage.

4. The automatic power switching system according to claim 3, characterized in that: The first conductive device includes a first diode, an anode of the first diode is configured as the first end, and a cathode of the first diode is configured as the second end.

5. The automatic power switching system according to claim 3, characterized in that: The second conductive device includes a MOS transistor, the drain of the MOS transistor is configured as the third end, the gate of the MOS transistor is configured as the fourth end, and the source of the MOS transistor is configured as the fifth end.

6. The automatic power switching system according to claim 1, characterized in that: Also includes: The first voltage conversion circuit includes a third input terminal and a second output terminal, the third input terminal is configured to input a third voltage, and the second output terminal is configured to output the first voltage.

7. The automatic power switching system according to claim 6, characterized in that: The first voltage conversion circuit includes a transient voltage protection device, an anti-reverse connection device, a common mode suppression device, and a first DC conversion device. The transient voltage protection device includes a sixth terminal and a seventh terminal. The anti-reverse connection device includes an eighth terminal and a ninth terminal. The common mode suppression device includes a tenth terminal, an eleventh terminal, a twelfth terminal, and a thirteenth terminal. The first DC conversion device includes a fourteenth terminal and a fifteenth terminal. The sixth terminal is configured to be connected to the third input terminal and the tenth terminal respectively, the seventh terminal is configured to be connected to the eleventh terminal, the twelfth terminal is configured to be connected to the eighth terminal, the thirteenth terminal is configured to be connected to the ninth terminal and the fourteenth terminal respectively, and the fifteenth terminal is configured to be connected to the second output terminal.

8. The automatic power switching system according to claim 1, characterized in that: Also includes: The second voltage conversion circuit includes a fourth input terminal and a third output terminal, the fourth input terminal is configured to input a fourth voltage, and the third output terminal is configured to output the second voltage.

9. The automatic power switching system according to claim 8, characterized in that: The second voltage conversion circuit includes a second DC conversion device, and the second DC conversion device includes a sixteenth terminal and a seventeenth terminal. The sixteenth terminal is configured to be connected to the fourth input terminal, and the seventeenth terminal is configured to be connected to the third output terminal.

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