Power supply switching circuit of portable power supply

Abstract

The utility model provides a power supply switching circuit of a portable power supply. The power supply switching circuit comprises a DC charging interface, a DC input overvoltage protection sub-circuit, a photovoltaic charging interface, a photovoltaic input voltage comparison sub-circuit, an MOS tube driving sub-circuit and a photovoltaic input port. The direct current charging interface is connected to the MOS tube driving sub-circuit through the direct current input overvoltage protection sub-circuit, the photovoltaic charging interface is connected to the MOS tube driving sub-circuit through the photovoltaic input voltage comparison sub-circuit, and the MOS tube driving sub-circuit is connected to the photovoltaic input port; and the photovoltaic input port is connected with a photovoltaic controller of the portable power supply. According to the invention, direct-current and photovoltaic simultaneous input can be supported, and automatic switching between direct-current charging and photovoltaic charging can be realized without additionally arranging a converter.

Description

Technical Field

[0001] The utility model relates to the technical field of portable power supplies, in particular to a power supply switching circuit of a portable power supply. Background Art

[0002] In recent years, with the popularity of outdoor sports, more and more people are camping outdoors, and the proportion of people using outdoor electrical appliances is increasing. The popularity of outdoor portable power supplies is also increasing. There are many ways to charge portable power supplies, including AC charging, photovoltaic charging, and DC charging. DC charging and photovoltaic charging usually have two different interfaces due to different power supply equipment. Considering the cost, there is usually only one circuit at the back end, that is, the circuit meets the charging input of DC and photovoltaic at the same time. At this time, the photovoltaic and DC charging ports cannot be simply connected in parallel, otherwise it is easy to cause high voltage photovoltaic backflow to the DC charging port and damage the circuit. There are mainly two types of circuits at present:

[0003] 1. There is only one interface, and the external interface converter is used to switch between different charging modes. However, the interface converter is not universal, and the usual photovoltaic panels may not be compatible with the converter;

[0004] 2. DC charging and photovoltaic charging are implemented independently using two circuits, that is, two charging circuits are used, which increases the cost. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a power supply switching circuit of a portable power supply, which supports simultaneous input of DC and photovoltaic, and realizes automatic switching between DC charging and photovoltaic charging without adding an additional converter.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] A power supply switching circuit for a portable power source, comprising a DC charging interface, a DC input overvoltage protection subcircuit, a photovoltaic charging interface, a photovoltaic input voltage comparison subcircuit, a MOS tube driving subcircuit and a photovoltaic input port;

[0008] The DC charging interface is connected to the MOS tube driving subcircuit through the DC input overvoltage protection subcircuit, the photovoltaic charging interface is connected to the MOS tube driving subcircuit through the photovoltaic input voltage comparison subcircuit, and the MOS tube driver is connected to the photovoltaic input port;

[0009] The photovoltaic input port is connected to a photovoltaic controller of a portable power source.

[0010] Further, the photovoltaic input voltage comparison subcircuit includes a first voltage stabilizing diode, a first anti-backflow diode, a first voltage dividing resistor, a second voltage dividing resistor, a comparator, a first comparison resistor and a second comparison resistor;

[0011] The DC input overvoltage protection subcircuit includes a second voltage stabilizing diode, a second reverse current protection diode, a third voltage dividing resistor, a fourth voltage dividing resistor, a transistor and a collector resistor;

[0012] The MOS tube driving subcircuit includes a first MOS tube, a second MOS tube, a third voltage regulator diode, a first driving resistor and a second driving resistor;

[0013] The drain of the first MOS tube is connected to the drain of the second MOS tube, the first driving resistor is connected in parallel to the gate and source of the first MOS tube, and the source of the first MOS tube is also connected to the photovoltaic input port, the second driving resistor is connected in parallel to the source and gate of the second MOS tube, and the positive terminal and negative terminal of the third voltage regulator diode are respectively connected to the source and gate of the second MOS tube;

[0014] The positive terminal of the first anti-backflow diode is connected to the charging positive electrode of the photovoltaic charging interface and the photovoltaic input port, the negative terminal of the first anti-backflow diode is connected to the negative input pin of the comparator and the negative terminal of the first voltage-stabilizing diode through the first voltage-dividing resistor, and the negative input pin of the comparator is also connected to the photovoltaic input port and ground respectively through the second voltage-dividing resistor, the positive terminal of the first voltage-stabilizing diode is connected to the photovoltaic input port, the positive input pin of the comparator is connected to a +5V voltage, and the positive input pin and the output pin of the comparator are connected in series with the first comparison resistor, and the output pin of the comparator is also connected to the gate of the first MOS tube through the second comparison resistor;

[0015] The positive terminal of the second anti-backcurrent diode is connected to the charging positive electrode of the DC charging interface and the photovoltaic input port, the negative terminal of the second anti-backcurrent diode is connected to the collector of the transistor through a collector resistor, the negative terminal of the second anti-backcurrent diode is also connected to the base of the transistor through a third voltage-dividing resistor, the second voltage-stabilizing diode is connected in series between the third voltage-dividing resistor and the base of the transistor, and the positive terminal of the second voltage-stabilizing diode is connected to the base of the transistor, and the negative terminal is connected to the third voltage-dividing resistor, the base of the transistor is also respectively connected to the emitter of the transistor and the charging negative electrode of the DC charging interface through a fourth voltage-dividing resistor, and the emitter of the transistor is also connected to the source of the second MOS tube;

[0016] The negative charging pole of the photovoltaic charging interface is grounded.

[0017] Further, the photovoltaic input voltage comparison subcircuit also includes a first filter capacitor and a first reference resistor;

[0018] The first filter capacitor and the first reference resistor are connected in parallel between the positive input pin of the comparator and the source of the first MOS tube.

[0019] Further, the photovoltaic input voltage comparison subcircuit also includes a second filter capacitor;

[0020] The second filter capacitor is connected in parallel to two ends of the second voltage-dividing resistor.

[0021] Furthermore, the photovoltaic input voltage comparison subcircuit further includes a third filter capacitor and a second reference resistor;

[0022] The second reference resistor is connected in series between the +5V voltage and the positive input pin of the comparator;

[0023] The third filter capacitor is connected in parallel to both ends of the second reference resistor.

[0024] Furthermore, the first MOS transistor and the second MOS transistor are both N-channel field effect transistors;

[0025] The transistor is an NPN transistor;

[0026] The comparator is a LM321A comparator, comprising 5 pins;

[0027] Pin 1 and pin 3 are respectively the positive terminal and negative terminal input of the comparator, pin 4 is the comparison output pin, and pin 2 and pin 5 are respectively the ground pin and the power supply pin.

[0028] The beneficial effects of the utility model are as follows: a power supply switching circuit of a portable power supply is provided, by adding a switching circuit to the original DC charging and photovoltaic charging circuits, including a DC input overvoltage protection subcircuit, a photovoltaic input voltage comparison subcircuit and a MOS tube driving subcircuit, wherein the DC charging interface is connected to the DC input overvoltage protection subcircuit for limitation to prevent excessive voltage from being input to the DC side during DC charging, the photovoltaic charging interface is connected to the photovoltaic input voltage comparison subcircuit to compare the voltages of the photovoltaic charging side and the DC charging side to prevent the high voltage of the photovoltaic charging from being backflowed to the DC charging side, and then the power voltage and current flow circuit are provided by the MOS tube to charge the battery through the photovoltaic input port at the rear end of the portable mobile power supply, and the automatic switching between DC charging and photovoltaic charging is realized without the need for an additional converter under the condition of supporting simultaneous DC and photovoltaic inputs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1It is a structural framework diagram of a power supply switching circuit of a portable power source according to an embodiment of the utility model;

[0030] Figure 2 The present invention is a circuit diagram of a power supply switching circuit of a portable power source according to an embodiment of the present invention.

[0031] Description of labels:

[0032] PV_IN, photovoltaic charging interface; DC_IN, DC charging interface; PV_OUT, photovoltaic input port;

[0033] Z1, first voltage-stabilizing diode; D1, first anti-backflow diode; R1, first voltage-dividing resistor;

[0034] R5, second voltage-dividing resistor; U1, comparator; R4, first comparison resistor; R2, second comparison resistor;

[0035] C1, first filter capacitor; R11, first reference resistor; C2, second filter capacitor; C3, third filter capacitor; R6, second reference resistor;

[0036] Z2, the second voltage-stabilizing diode; D2, the second anti-backflow diode; R8, the third voltage-dividing resistor;

[0037] R9, the fourth voltage-dividing resistor; Q3, the transistor; R7, the collector resistor;

[0038] Q1, a first MOS tube; Q2, a second MOS tube; Z3, a third voltage-stabilizing diode; R3, a first driving resistor; R12, a second driving resistor. DETAILED DESCRIPTION

[0039] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0040] Please refer to Figure 1 and Figure 2 , a power supply switching circuit of a portable power supply, including a DC charging interface, a DC input overvoltage protection subcircuit, a photovoltaic charging interface, a photovoltaic input voltage comparison subcircuit, a MOS tube driving subcircuit and a photovoltaic input port;

[0041] The DC charging interface is connected to the MOS tube driving subcircuit through the DC input overvoltage protection subcircuit, the photovoltaic charging interface is connected to the MOS tube driving subcircuit through the photovoltaic input voltage comparison subcircuit, and the MOS tube driver is connected to the photovoltaic input port;

[0042] The photovoltaic input port is connected to a photovoltaic controller of a portable power source.

[0043] From the above description, it can be seen that the beneficial effect of the utility model is: to provide a power supply switching circuit for a portable power supply, by adding a switching circuit to the original DC charging and photovoltaic charging circuits, including a DC input overvoltage protection subcircuit, a photovoltaic input voltage comparison subcircuit and a MOS tube driving subcircuit, wherein the DC charging interface is connected to the DC input overvoltage protection subcircuit for limitation to prevent excessive voltage from being input to the DC side during DC charging, and the photovoltaic charging interface is connected to the photovoltaic input voltage comparison subcircuit to compare the voltages on the photovoltaic charging side and the DC charging side to prevent the high voltage of the photovoltaic charging from being backflowed to the DC charging side, and then the power voltage and current flow circuit are provided by the MOS tube to charge the battery through the photovoltaic input port at the rear end of the portable mobile power supply, and the DC charging and photovoltaic charging can be automatically switched without the need for an additional converter under the condition of supporting simultaneous DC and photovoltaic input.

[0044] Further, the photovoltaic input voltage comparison subcircuit includes a first voltage stabilizing diode, a first anti-backflow diode, a first voltage dividing resistor, a second voltage dividing resistor, a comparator, a first comparison resistor and a second comparison resistor;

[0045] The DC input overvoltage protection subcircuit includes a second voltage stabilizing diode, a second reverse current protection diode, a third voltage dividing resistor, a fourth voltage dividing resistor, a transistor and a collector resistor;

[0046] The MOS tube driving subcircuit includes a first MOS tube, a second MOS tube, a third voltage regulator diode, a first driving resistor and a second driving resistor;

[0047] The drain of the first MOS tube is connected to the drain of the second MOS tube, the first driving resistor is connected in parallel to the gate and source of the first MOS tube, and the source of the first MOS tube is also connected to the photovoltaic input port, the second driving resistor is connected in parallel to the source and gate of the second MOS tube, and the positive terminal and negative terminal of the third voltage regulator diode are respectively connected to the source and gate of the second MOS tube;

[0048] The positive terminal of the first anti-backflow diode is connected to the charging positive electrode of the photovoltaic charging interface and the photovoltaic input port, the negative terminal of the first anti-backflow diode is connected to the negative input pin of the comparator and the negative terminal of the first voltage-stabilizing diode through the first voltage-dividing resistor, and the negative input pin of the comparator is also connected to the photovoltaic input port and ground respectively through the second voltage-dividing resistor, the positive terminal of the first voltage-stabilizing diode is connected to the photovoltaic input port, the positive input pin of the comparator is connected to a +5V voltage, and the positive input pin and the output pin of the comparator are connected in series with the first comparison resistor, and the output pin of the comparator is also connected to the gate of the first MOS tube through the second comparison resistor;

[0049] The positive terminal of the second anti-backcurrent diode is connected to the charging positive electrode of the DC charging interface and the photovoltaic input port, the negative terminal of the second anti-backcurrent diode is connected to the collector of the transistor through a collector resistor, the negative terminal of the second anti-backcurrent diode is also connected to the base of the transistor through a third voltage-dividing resistor, the second voltage-stabilizing diode is connected in series between the third voltage-dividing resistor and the base of the transistor, and the positive terminal of the second voltage-stabilizing diode is connected to the base of the transistor, and the negative terminal is connected to the third voltage-dividing resistor, the base of the transistor is also respectively connected to the emitter of the transistor and the charging negative electrode of the DC charging interface through a fourth voltage-dividing resistor, and the emitter of the transistor is also connected to the source of the second MOS tube;

[0050] The negative charging pole of the photovoltaic charging interface is grounded.

[0051] As can be seen from the above description, each subcircuit is connected to each other through corresponding electronic components, wherein the second voltage-stabilizing diode in the DC input overvoltage comparison subcircuit and the third voltage-dividing resistor and the fourth voltage-dividing resistor form a voltage value, which is compared with the input voltage of the DC charging interface. When the input voltage of the DC charging interface is greater than the voltage value formed by the second voltage-stabilizing diode, the third voltage-dividing resistor and the fourth voltage-dividing resistor, the transistor is turned on and the second MOS tube is turned off, then the input voltage of the DC charging interface will not be able to enter through the DC charging interface to prevent excessive voltage from being input on the DC side; and the photovoltaic input voltage comparison subcircuit compares the photovoltaic input voltage value of the photovoltaic charging interface through a comparator, and cooperates with the voltage-dividing circuit composed of the first voltage-dividing resistor and the second voltage-dividing resistor to obtain a reference voltage value as a comparison value. When the photovoltaic input voltage value is greater than the reference voltage after being divided by the first anti-reverse current diode, the first voltage-dividing resistor and the second voltage-dividing resistor, the comparator will not be able to output, that is, the first MOS tube section, then the voltage of the photovoltaic charging interface will not be backflowed to the DC charging interface, thereby not damaging the electrical components on the DC low-voltage side, and at the same time, the first voltage-stabilizing diode can be used to protect the comparator to prevent it from being damaged by overvoltage.

[0052] Further, the photovoltaic input voltage comparison subcircuit also includes a first filter capacitor and a first reference resistor;

[0053] The first filter capacitor and the first reference resistor are connected in parallel between the positive input pin of the comparator and the source of the first MOS tube.

[0054] From the above description, it can be seen that the first filter capacitor can effectively filter and protect the first MOS tube and the comparator. At the same time, the first reference resistor can cooperate with +5V to form a reference voltage for comparing the positive terminal voltage of the comparator.

[0055] Further, the photovoltaic input voltage comparison subcircuit also includes a second filter capacitor;

[0056] The second filter capacitor is connected in parallel to two ends of the second voltage-dividing resistor.

[0057] It can be seen from the above description that the second filter capacitor can play a role in protecting the voltage divider circuit.

[0058] Furthermore, the photovoltaic input voltage comparison subcircuit further includes a third filter capacitor and a second reference resistor;

[0059] The second reference resistor is connected in series between the +5V voltage and the positive input pin of the comparator;

[0060] The third filter capacitor is connected in parallel to both ends of the second reference resistor.

[0061] From the above description, it can be seen that the third filter capacitor can further effectively play the role of filtering and protecting the comparator, and the second reference resistor can cooperate with +5V to form a reference voltage for comparing the positive terminal voltage of the comparator.

[0062] Furthermore, the first MOS transistor and the second MOS transistor are both N-channel field effect transistors;

[0063] The transistor is an NPN transistor;

[0064] The comparator is a LM321A comparator, comprising 5 pins;

[0065] Pin 1 and pin 3 are respectively the positive terminal and negative terminal input of the comparator, pin 4 is the comparison output pin, and pin 2 and pin 5 are respectively the ground pin and the power supply pin.

[0066] It can be seen from the above description that the MOS tubes, triodes and comparators in each sub-circuit adopt corresponding models to improve the service life of the circuit.

[0067] The utility model provides a power supply switching circuit for a portable power source, which is mainly used in photovoltaic and DC charging scenarios of a portable mobile power source. The following is a specific description in conjunction with a specific embodiment:

[0068] Please refer to Figure 1 , Embodiment 1 of the present utility model is:

[0069] A power supply switching circuit for a portable power supply, such as Figure 1 As shown, it includes a DC charging interface DC_IN, a DC input overvoltage protection subcircuit, a photovoltaic charging interface PV_IN, a photovoltaic input voltage comparison subcircuit, a MOS tube driving subcircuit and a photovoltaic input port PV_OUT.

[0070] Among them, in this embodiment, the DC charging interface DC_IN is connected to the MOS tube driving subcircuit through the DC input overvoltage protection subcircuit, the photovoltaic charging interface PV_IN is connected to the MOS tube driving subcircuit through the photovoltaic input voltage comparison subcircuit, and the MOS tube driver is connected to the photovoltaic input port PV_OUT; and the photovoltaic input port PV_OUT is connected to the photovoltaic controller of the portable power supply, thereby realizing charging of the portable power supply.

[0071] That is, in this embodiment, a switching circuit is added to the original DC charging and photovoltaic charging circuits, including a DC input overvoltage protection subcircuit, a photovoltaic input voltage comparison subcircuit and a MOS tube driving subcircuit, wherein the DC charging interface DC_IN is connected to the DC input overvoltage protection subcircuit for limitation to prevent excessive voltage from being input to the DC side during DC charging, and the photovoltaic charging interface PV_IN is connected to the photovoltaic input voltage comparison subcircuit to compare the voltages of the photovoltaic charging side and the DC charging side to prevent the high voltage of the photovoltaic charging from flowing back to the DC charging side, and then the MOS tube provides the power voltage and current flow circuit to charge the battery through the photovoltaic input port PV_OUT at the rear end of the portable mobile power supply, and the DC charging and photovoltaic charging are automatically switched without adding an additional converter under the support of simultaneous DC and photovoltaic input.

[0072] Please refer to Figure 2 , Embodiment 2 of the present utility model is:

[0073] A power supply switching circuit of a portable power source, based on the above-mentioned embodiment 1, in this embodiment, as Figure 2 As shown, the photovoltaic input voltage comparison subcircuit includes a first voltage stabilizing diode Z1, a first anti-reverse current diode D1, a first voltage dividing resistor R1, a second voltage dividing resistor R5, a comparator U1, a first comparison resistor R4 and a second comparison resistor R2; the DC input overvoltage protection subcircuit includes a second voltage stabilizing diode Z2, a second anti-reverse current diode D2, a third voltage dividing resistor R8, a fourth voltage dividing resistor R9, a transistor Q3 and a collector resistor R7; the MOS tube driving subcircuit includes a first MOS tube Q1, a second MOS tube Q2, a third voltage stabilizing diode Z3, a first driving resistor R3 and a second driving resistor R12.

[0074] Among them, in this embodiment, the first MOS transistor Q1 and the second MOS transistor Q2 are both N-channel field effect transistors, the transistor Q3 is an NPN transistor Q3, and the comparator U1 is an LM321A comparator, including 5 pins, wherein pin 1 and pin 3 are respectively the positive and negative inputs of the comparator, pin 4 is the comparison output pin, and pin 2 and pin 5 are respectively the ground pin and the power supply pin, so as to meet the circuit principle and realize the corresponding function.

[0075] In this embodiment, the drain of the first MOS tube Q1 is connected to the drain of the second MOS tube Q2, the first driving resistor R3 is connected in parallel to the gate and source of the first MOS tube Q1, and the source of the first MOS tube Q1 is also connected to the photovoltaic input port PV_OUT, the second driving resistor R12 is connected in parallel to the source and gate of the second MOS tube Q2, and the positive terminal and negative terminal of the third voltage regulator diode Z3 are respectively connected to the source and gate of the second MOS tube Q2; the positive terminal of the first anti-backflow diode D1 is connected to the charging positive electrode of the photovoltaic charging interface PV_IN and the photovoltaic input port PV_OUT, the negative terminal of the first anti-backflow diode D1 is connected to the negative input pin of the comparator U1 and the negative terminal of the first voltage regulator diode Z1 through the first voltage dividing resistor R1, and the negative input pin of the comparator U1 is also connected to the photovoltaic input port PV_OUT and ground through the second voltage dividing resistor R5, the positive terminal of the first voltage regulator diode Z1 is connected to the photovoltaic input port PV_OUT, and the positive input pin of the comparator U1 is connected to +5V voltage, and the positive input pin and output pin of the comparator U1 are connected in series with a first comparison resistor R4, and the output pin of the comparator U1 is also connected to the gate of the first MOS tube Q1 through a second comparison resistor R2; the positive terminal of the second anti-backcurrent diode is connected to the charging positive electrode of the DC charging interface DC_IN and the photovoltaic input port PV_OUT, the negative terminal of the second anti-backcurrent diode is connected to the collector of the transistor Q3 through a collector resistor R7, and the negative terminal of the second anti-backcurrent diode is also connected to the collector of the transistor Q3 through a third voltage-dividing resistor R8. 3, a second zener diode Z2 is connected in series between the third voltage-dividing resistor R8 and the base of the transistor Q3, and a positive terminal of the second zener diode Z2 is connected to the base of the transistor Q3, and a negative terminal is connected to the third voltage-dividing resistor R8, the base of the transistor Q3 is also connected to the emitter of the transistor Q3 and the charging negative electrode of the DC charging interface DC_IN through a fourth voltage-dividing resistor R9, and the emitter of the transistor Q3 is also connected to the source of the second MOS tube Q2; the charging negative electrode of the photovoltaic charging interface PV_IN is grounded.

[0076] That is, in this embodiment, each subcircuit is connected to each other through corresponding electronic components, wherein the second voltage stabilizing diode Z2 in the DC input overvoltage comparison subcircuit and the third voltage dividing resistor R8 and the fourth voltage dividing resistor R9 form a voltage value, which is compared with the input voltage of the DC charging interface DC_IN. When the input voltage of the DC charging interface DC_IN is greater than the voltage value formed by the second voltage stabilizing diode Z2, the third voltage dividing resistor R8 and the fourth voltage dividing resistor R9, the transistor Q3 is turned on and the second MOS tube Q2 is turned off, then the input voltage of the DC charging interface DC_IN will not be able to enter through the DC charging interface DC_IN to prevent excessive voltage from being input to the DC side; and the photovoltaic output The input voltage comparison subcircuit compares the photovoltaic input voltage value of the photovoltaic charging interface PV_IN through the comparator U1, and cooperates with the voltage divider circuit composed of the first voltage divider resistor R1 and the second voltage divider resistor R5 to obtain a reference voltage value as a comparison value. When the photovoltaic input voltage value is greater than the reference voltage after being divided by the first anti-reverse current diode D1, the first voltage divider resistor R1 and the second voltage divider resistor R5, the comparator U1 will not be able to output, that is, the first MOS tube Q1 section, and the voltage of the photovoltaic charging interface PV_IN will not be backflowed to the DC charging interface DC_IN, thereby not damaging the electrical components on the DC low-voltage side. At the same time, the first voltage stabilizing diode Z1 can be used to protect the comparator U1 to prevent it from being damaged by overvoltage.

[0077] For example Figure 2 As shown, the photovoltaic input voltage comparison subcircuit also includes a first filter capacitor C1, a first reference resistor R11, a second filter capacitor C2, a third filter capacitor C3 and a second reference resistor R6, wherein the first filter capacitor C1 and the first reference resistor R11 are connected in parallel between the positive input pin of the comparator U1 and the source of the first MOS tube Q1, the second filter capacitor C2 is connected in parallel between the two ends of the second voltage-dividing resistor R5, the second reference resistor R6 is connected in series between the +5V voltage and the positive input pin of the comparator U1, and the third filter capacitor C3 is connected in parallel between the two ends of the second reference resistor R6.

[0078] The first filter capacitor C1 can effectively filter and protect the first MOS tube Q1 and the comparator U1, the second filter capacitor C2 can protect the voltage divider circuit, and the third filter capacitor C3 can further effectively filter and protect the comparator U1. The first reference resistor R11 and the second reference resistor cooperate with +5V to form a reference voltage for comparing the positive terminal voltage of the comparator U1.

[0079] In addition, in the present embodiment, the first anti-backflow diode D1 and the second anti-backflow diode D2 are both IN4148WS model with a withstand voltage of 100V; the first voltage-dividing resistor R1 and the second voltage-dividing resistor R5 are configured according to the required voltage, and the resistance range is from tens to more than one hundred kiloohms; the first reference resistor R11 and the second reference resistor R6 provide a reference voltage, and their resistance is generally from several thousand ohms to tens of ohms; the first filter capacitor C1, the second filter capacitor C2 and the third filter capacitor C3 are all 0.1μF; the resistance of the second comparison resistor R2 is 1KΩ; the first drive resistor R3, the first comparison resistor R4 and The resistance of the second driving resistor R12 is 100KΩ; the third voltage-dividing resistor R8 and the fourth voltage-dividing resistor R9 are configured according to needs, and their resistances are generally tens of kiloohms to more than one hundred kiloohms; the first voltage-stabilizing diode Z1 and the third voltage-stabilizing diode Z3 are both MM1Z12B, and the model of the second voltage-stabilizing diode Z2 can be selected according to the required voltage, and can also be a MMIZ series product; the first MOS tube Q1 and the second MOS tube Q2 are both power MOS tubes, which can be selected according to the required current and voltage, and the currently used model is NCEP60T12AK, 60V / 120A mos.

[0080] In summary, the utility model provides a portable power supply switching circuit, which has the following features:

[0081] Beneficial effects:

[0082] 1. Support DC and photovoltaic input at the same time;

[0083] 2. Effectively prevent excessive voltage from being input on the DC side;

[0084] 3. Effectively prevent the photovoltaic high voltage from flowing back to the DC low voltage side;

[0085] 4. No additional converter is required.

[0086] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A power supply switching circuit for a portable power source, characterized in that: It includes a DC charging interface, a DC input overvoltage protection subcircuit, a photovoltaic charging interface, a photovoltaic input voltage comparison subcircuit, a MOS tube driving subcircuit and a photovoltaic input port; The DC charging interface is connected to the MOS tube driving subcircuit through the DC input overvoltage protection subcircuit, the photovoltaic charging interface is connected to the MOS tube driving subcircuit through the photovoltaic input voltage comparison subcircuit, and the MOS tube driver is connected to the photovoltaic input port; The photovoltaic input port is connected to a photovoltaic controller of a portable power source.

2. A power supply switching circuit for a portable power source according to claim 1, characterized in that: The photovoltaic input voltage comparison subcircuit includes a first voltage stabilizing diode, a first anti-backflow diode, a first voltage dividing resistor, a second voltage dividing resistor, a comparator, a first comparison resistor and a second comparison resistor; The DC input overvoltage protection subcircuit includes a second voltage stabilizing diode, a second reverse current protection diode, a third voltage dividing resistor, a fourth voltage dividing resistor, a transistor and a collector resistor; The MOS tube driving subcircuit includes a first MOS tube, a second MOS tube, a third voltage regulator diode, a first driving resistor and a second driving resistor; The drain of the first MOS tube is connected to the drain of the second MOS tube, the first driving resistor is connected in parallel to the gate and source of the first MOS tube, and the source of the first MOS tube is also connected to the photovoltaic input port, the second driving resistor is connected in parallel to the source and gate of the second MOS tube, and the positive terminal and negative terminal of the third voltage regulator diode are respectively connected to the source and gate of the second MOS tube; The positive terminal of the first anti-backflow diode is connected to the charging positive electrode of the photovoltaic charging interface and the photovoltaic input port, the negative terminal of the first anti-backflow diode is connected to the negative input pin of the comparator and the negative terminal of the first voltage-stabilizing diode through the first voltage-dividing resistor, and the negative input pin of the comparator is also connected to the photovoltaic input port and ground respectively through the second voltage-dividing resistor, the positive terminal of the first voltage-stabilizing diode is connected to the photovoltaic input port, the positive input pin of the comparator is connected to a +5V voltage, and the positive input pin and the output pin of the comparator are connected in series with the first comparison resistor, and the output pin of the comparator is also connected to the gate of the first MOS tube through the second comparison resistor; The positive terminal of the second anti-backcurrent diode is connected to the charging positive electrode of the DC charging interface and the photovoltaic input port, the negative terminal of the second anti-backcurrent diode is connected to the collector of the transistor through a collector resistor, the negative terminal of the second anti-backcurrent diode is also connected to the base of the transistor through a third voltage-dividing resistor, the second voltage-stabilizing diode is connected in series between the third voltage-dividing resistor and the base of the transistor, and the positive terminal of the second voltage-stabilizing diode is connected to the base of the transistor, and the negative terminal is connected to the third voltage-dividing resistor, the base of the transistor is also connected to the emitter of the transistor and the charging negative electrode of the DC charging interface through a fourth voltage-dividing resistor, and the emitter of the transistor is also connected to the source of the second MOS tube; The negative charging pole of the photovoltaic charging interface is grounded.

3. The power supply switching circuit of a portable power source according to claim 2, characterized in that: The photovoltaic input voltage comparison subcircuit also includes a first filter capacitor and a first reference resistor; The first filter capacitor and the first reference resistor are connected in parallel between the positive input pin of the comparator and the source of the first MOS tube.

4. The power supply switching circuit of a portable power source according to claim 2, characterized in that: The photovoltaic input voltage comparison subcircuit also includes a second filter capacitor; The second filter capacitor is connected in parallel to two ends of the second voltage-dividing resistor.

5. The power supply switching circuit of a portable power source according to claim 2, characterized in that: The photovoltaic input voltage comparison subcircuit further includes a third filter capacitor and a second reference resistor; The second reference resistor is connected in series between the +5V voltage and the positive input pin of the comparator; The third filter capacitor is connected in parallel to both ends of the second reference resistor.

6. The power supply switching circuit of a portable power source according to claim 2, characterized in that: The first MOS transistor and the second MOS transistor are both N-channel field effect transistors; The transistor is an NPN transistor; The comparator is a LM321A comparator, comprising 5 pins; Pin 1 and pin 3 are respectively the positive terminal and negative terminal input of the comparator, pin 4 is the comparison output pin, and pin 2 and pin 5 are respectively the ground pin and the power supply pin.

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