CN217486227U - Lithium battery and external power supply switching circuit - Google Patents
Lithium battery and external power supply switching circuit Download PDFInfo
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- CN217486227U CN217486227U CN202221600930.7U CN202221600930U CN217486227U CN 217486227 U CN217486227 U CN 217486227U CN 202221600930 U CN202221600930 U CN 202221600930U CN 217486227 U CN217486227 U CN 217486227U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
- Y04S20/20—End-user application control systems
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Abstract
The utility model discloses a lithium cell and external power source switching circuit that supplies power relates to the electronic circuit field. The utility model discloses a first P channel field effect transistor, second P channel field effect transistor, NPN transistor, zener diode, schottky diode, first resistance, second resistance, third resistance, fourth resistance and boost circuit. The utility model discloses when no external power supply, through output after boost circuit rises lithium battery voltage to 5V, when having external power supply input, directly export external power supply, and avoid the battery to discharge, switch over the return circuit and adopt the field effect transistor, turn on the pressure and reduce, the loss is little, and control circuit is simple, and the cost is lower.
Description
Technical Field
The utility model belongs to the electronic circuit field especially relates to a circuit that is used for power supply to switch between lithium cell and the external power source.
Background
Some electronic devices are powered by lithium batteries, the voltage is boosted to 5V through a booster circuit, and when an external 5V power supply is input, the external power supply is used for supplying power, and the lithium batteries are forbidden to discharge; the existing power path management circuit generally adopts the charge and discharge management of a lithium battery, the output voltage of the circuit is the battery voltage, the 5V can be obtained only by a voltage boosting and stabilizing circuit at the later stage, and the links from the externally input 5V to the output of the 5V at the later stage are more and more complex.
SUMMERY OF THE UTILITY MODEL
The utility model provides a lithium cell and external power source power supply switching circuit, when not having the external power supply, export after rising to 5V with the lithium cell voltage through boost circuit, when having external power source input, directly export external power source, solved the problem among the background art.
In order to solve the technical problem, the utility model discloses a realize through following technical scheme:
the utility model discloses a lithium cell and external power supply switching circuit, including first P channel field effect transistor, second P channel field effect transistor, NPN transistor, zener diode, schottky diode, first resistance, second resistance, third resistance, fourth resistance and boost circuit;
the 5V input end of the external power supply is connected with the drain electrode of the first P-channel field effect transistor, the cathode of the voltage stabilizing diode and the anode of the Schottky diode; the source electrode of the first P-channel field effect transistor is connected with one end of the first resistor and connected with the 5V output, and the grid electrode of the first P-channel field effect transistor and the other end of the first resistor are connected with the collector electrode of the NPN transistor in parallel; the anode of the voltage stabilizing diode is connected with one end of the second resistor, the other end of the second resistor is connected with one end of the third resistor and is connected with the base electrode of the NPN transistor in parallel, and the other end of the third resistor and the emitter of the NPN transistor are grounded; the source electrode of the second P-channel field effect transistor is connected with the anode of the battery;
the drain electrode of the second P-channel field effect transistor is connected with the input of the booster circuit, and the grid electrode of the second P-channel field effect transistor is connected with the cathode of the Schottky diode and is simultaneously connected with one end of a fourth resistor; the other end of the fourth resistor is connected with GND, and the booster circuit outputs 5V voltage and 5V output.
Compared with the prior art, the utility model following beneficial effect is included:
the utility model discloses a lithium cell and external power source power supply switching circuit, when not having external power supply, through output after boost circuit rises the lithium cell voltage to 5V, when having external power source input, directly export external power source, and avoid the battery to discharge, switching circuit adopts field effect transistor, and the breakover voltage reduces, and the loss is little, and control circuit is simple, and the cost is lower.
Of course, it is not necessary for any particular product to achieve all of the above-described advantages simultaneously.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a power supply switching circuit for a lithium battery and an external power supply according to the present invention;
in the drawings, the reference numbers indicate the following list of parts:
q1-first P channel field effect transistor, Q2-second P channel field effect transistor, Q3-NPN transistor, D1-voltage stabilizing diode, D2-Schottky diode, R1-first resistor, R2-second resistor, R3-third resistor, and R4-fourth resistor.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without making creative efforts belong to the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "end", "one end", "the other end", and the like indicate an orientation or positional relationship merely for convenience of description and simplicity of description, and do not indicate or imply that the components or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
Referring to fig. 1, the present invention relates to a switching circuit for supplying power to a lithium battery and an external power source, including a first P-channel fet Q1, a second P-channel fet Q2, an NPN transistor Q3, a zener diode D1, a schottky diode D2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a voltage boost circuit; in this specific embodiment, the first P channel fet Q1 is specifically AO3401A, the second P channel fet Q2 is specifically AO3401A, the NPN transistor Q3 is specifically MMBT3904, the resistance of the first resistor R1 is 100K Ω, the resistance of the second resistor R2 is 10K Ω, the resistance of the third resistor R3 is 10K Ω, the resistance of the fourth resistor R4 is 100K Ω, the model of the zener diode D1 is BZT52C3V3, and the specific model of the schottky diode D2 is SD103 AWS;
the 5V regulated front voltage input end (i.e. 5VIN in figure 1) of the external power supply is connected with the drain electrode of the first P-channel field effect transistor Q1, the cathode of the voltage-stabilizing diode D1 and the anode of the Schottky diode D2; the source electrode of the first P-channel field effect transistor Q1 is connected with one end of the first resistor R1 and connected with 5V output, and the grid electrode of the first P-channel field effect transistor Q1 and the other end of the first resistor R1 are connected with the collector electrode of an NPN transistor Q3 in parallel; the anode of the voltage stabilizing diode D1 is connected with one end of a second resistor R2, the other end of the second resistor R2 is connected with one end of a third resistor R3 and is connected with the base of an NPN transistor Q3, and the other end of the third resistor R3 is connected with the emitter of an NPN transistor Q3 and is connected with GND; the zener diode D1 is specifically a 3.3V zener diode;
the source electrode of the second P-channel field effect transistor Q2 is connected with the anode of one end of the battery; the drain of the second P-channel field effect transistor Q2 is connected with the input of the booster circuit, and the grid is connected with the cathode of the Schottky diode D2 and one end of a fourth resistor R4; the other end of the fourth resistor R4 is connected with GND, and the booster circuit outputs 5V voltage and 5V output.
When no 5V power supply is input from the outside, the 5VIN is 0V, the voltage stabilizing diode D1 is not broken down, the NPN transistor Q3 is not conducted, and the first P-channel field effect transistor Q1 is not conducted; the grid electrode of the second P-channel field effect transistor Q2 is pulled low through the fourth resistor R4, the second P-channel field effect transistor Q2 is conducted, and the battery voltage is boosted to 5V through the booster circuit and then output;
when a 5V power supply is input from the outside, the 5VIN is 5V, the voltage stabilizing diode D1 breaks down, the NPN transistor Q3 is conducted, the first P-channel field effect transistor Q1 is conducted, and the 5V power supply is directly output; and the grid of the second P-channel field effect transistor Q2 is pulled high through the Schottky diode D2, the second P-channel field effect transistor Q2 is not conducted, and the booster circuit does not work.
The utility model discloses a lithium cell and external power source switching circuit, when not having external power supply, export after rising to 5V with the lithium cell voltage through boost circuit, when having external power source input, directly export external power source, and avoid the battery to discharge, switch over the return circuit and adopt the field effect transistor, turn on the pressure and reduce, the loss is little, and control circuit is simple, and the cost is lower.
The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best understand the invention for and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents.
Claims (1)
1. The power supply switching circuit of the lithium battery and the external power supply is characterized by comprising a first P-channel field effect transistor (Q1), a second P-channel field effect transistor (Q2), an NPN transistor (Q3), a voltage stabilizing diode (D1), a Schottky diode (D2), a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4) and a boosting circuit;
the 5V input end of the external power supply is connected with the drain electrode of the first P-channel field effect transistor (Q1), the cathode of the voltage-stabilizing diode (D1) and the anode of the Schottky diode (D2); the source of the first P-channel field effect transistor (Q1) is connected with one end of a first resistor (R1) and is connected with a 5V output, and the grid of the first P-channel field effect transistor (Q1) and the other end of the first resistor (R1) are connected with the collector of an NPN transistor (Q3); the anode of the voltage-stabilizing diode (D1) is connected with one end of a second resistor (R2), the other end of the second resistor (R2) is connected with one end of a third resistor (R3) and is connected with the base of an NPN transistor (Q3), and the other end of the third resistor (R3) and the emitter of the NPN transistor (Q3) are connected with GND; the source electrode of the second P-channel field effect transistor (Q2) is connected with the anode of the battery;
the drain of the second P-channel field effect transistor (Q2) is connected with the input of the booster circuit, and the grid is connected with the cathode of the Schottky diode (D2) and one end of a fourth resistor (R4); the other end of the fourth resistor (R4) is connected with GND, and the booster circuit outputs 5V voltage and is connected with 5V output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221600930.7U CN217486227U (en) | 2022-06-24 | 2022-06-24 | Lithium battery and external power supply switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221600930.7U CN217486227U (en) | 2022-06-24 | 2022-06-24 | Lithium battery and external power supply switching circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN217486227U true CN217486227U (en) | 2022-09-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202221600930.7U Active CN217486227U (en) | 2022-06-24 | 2022-06-24 | Lithium battery and external power supply switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN217486227U (en) |
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2022
- 2022-06-24 CN CN202221600930.7U patent/CN217486227U/en active Active
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