CN215185908U - Power supply selection circuit and power supply equipment - Google Patents
Power supply selection circuit and power supply equipment Download PDFInfo
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- CN215185908U CN215185908U CN202120508648.5U CN202120508648U CN215185908U CN 215185908 U CN215185908 U CN 215185908U CN 202120508648 U CN202120508648 U CN 202120508648U CN 215185908 U CN215185908 U CN 215185908U
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- power supply
- effect transistor
- field effect
- input end
- selection circuit
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Abstract
The utility model discloses a power selection circuit and power supply equipment, which comprises a main power input end and a battery power input end, wherein the main power input end is connected with a first field effect transistor, the battery power input end is connected with a second field effect transistor, and the source electrode of the first field effect transistor is connected with the source electrode of the second field effect transistor and is used as the output end of the power selection circuit; the first field effect transistor is connected with the first resistor and is connected with the input end of the battery power supply through the third resistor; the second field effect transistor is connected with the second resistor, the main power supply input end is connected with the second field effect transistor through the switch, two paths of power supplies are selected by adopting simple components, priority is provided, a charging function can be selected according to the type of the battery, control is simple, the design of a power supply selection circuit is simplified, and scheme cost is reduced.
Description
Technical Field
The utility model relates to the technical field of circuits, especially, relate to a power selection circuit and power supply unit.
Background
The power supply product is widely applied to various electronic devices, the power supply is the core foundation for ensuring the normal work of the electric equipment, and the battery can be used as a standby power supply or a secondary power supply.
The power input of an electric device may simultaneously comprise two or more input types, each input type needs to be output normally, and meanwhile, the problem of mutual isolation among multiple inputs is also considered, along with the wide application of the battery, the rechargeable battery can be used as a standby power supply or a second power supply, the battery needs to be charged when the battery is not detached, a special power supply selection chip or a switch is generally adopted to match with a control chip for input selection, so that the complexity of a circuit is inevitably increased, and the cost is increased.
The traditional multi-input single-output power supply is generally composed of a special power supply selection chip or a switch matching controller or simple diodes in parallel connection, the former two modes are generally high in cost because special chips are needed, the latter realizes isolation among multiple paths of input by utilizing unidirectional conductivity of the diodes, but voltage loss caused by the diodes cannot be avoided, the priority of each input is the same, and the batteries are difficult to charge in a system which adopts a rechargeable battery for power supply.
SUMMERY OF THE UTILITY MODEL
To the technical problem, the utility model provides a power selection circuit and power supply unit.
A first aspect of the present invention provides a power selection circuit, including a main power input terminal and a battery power input terminal, the main power input terminal is connected to a first field effect transistor, the battery power input terminal is connected to a second field effect transistor, and a source electrode of the first field effect transistor is connected to a source electrode of the second field effect transistor, and serves as an output terminal of the power selection circuit; the first field effect transistor is connected with a first resistor and is connected with the input end of the battery power supply through a third resistor;
the second field effect transistor is connected with the second resistor, and the main power supply input end is connected with the second field effect transistor through the switch.
Optionally, the main power input terminal is connected to a drain of the first fet, and the battery power input terminal is connected to a drain of the second fet.
Optionally, the gate of the first field effect transistor is connected to ground through a first resistor, and the gate of the first field effect transistor is connected to the battery power input terminal through a third resistor.
Optionally, the gate of the second fet is connected to ground through a second resistor, and the main power input terminal is connected to the gate of the second fet through a switch.
Optionally, the main power input end is connected to a positive end of a diode, and a negative end of the diode is connected to a source of the first field effect transistor.
Optionally, the switch is a key switch.
Optionally, the first field effect transistor and the second field effect transistor are both P-MOS transistors.
Optionally, the diode is a differential pressure diode.
The utility model discloses the second aspect still provides a power supply unit, including the power selection circuit of first aspect.
The embodiment of the utility model provides a power selection circuit and power supply unit, including main power input end and battery power input end, main power input end and first field effect transistor link to each other, and battery power input end and second field effect transistor link to each other, and the source electrode of first field effect transistor and the source electrode of second field effect transistor link to each other, as the output of power selection circuit; the first field effect transistor is connected with the first resistor and is connected with the input end of the battery power supply through the third resistor; the second field effect transistor is connected with the second resistor, the main power supply input end is connected with the second field effect transistor through the switch, two paths of power supplies are selected by adopting simple components, priority is provided, a charging function can be selected according to the type of the battery, control is simple, the design of a power supply selection circuit is simplified, and scheme cost is reduced.
Drawings
Fig. 1 is a schematic diagram of a power selection circuit according to an embodiment of the present invention.
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 in the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present invention.
Referring to fig. 1, an embodiment of the present invention includes: a power supply selection circuit comprises a main power supply input end and a battery power supply input end, wherein the main power supply input end is connected with a first field effect transistor, the battery power supply input end is connected with a second field effect transistor, and a source electrode of the first field effect transistor is connected with a source electrode of the second field effect transistor and serves as an output end of the power supply selection circuit; the first field effect transistor is connected with a first resistor and is connected with the input end of the battery power supply through a third resistor;
the second field effect transistor is connected with the second resistor, and the main power supply input end is connected with the second field effect transistor through the switch.
Specifically, in the embodiment of the present invention, the input terminal VIN1 is generally connected to a main input power source, the input terminal VIN2 is generally connected to a battery input, that is, to a battery power input terminal, the source S of the first fet Q1 and the second fet Q2 are connected together as the output terminal VOUT, the gate G of the first fet Q1 is grounded through the resistor R, the drain D of the first fet Q1 is connected to the input terminal VIN1, the drain D of the first fet Q2 is connected to the input terminal VIN2, meanwhile, the input terminal VIN1 is connected to the gate G of the second fet Q2 through the switch SW1, and the input terminal VIN2 is connected to the gate G of the first fet Q1 through the switch SW 1.
The embodiment of the utility model provides a power selection circuit, including main power input end and battery power input end, main power input end and first field effect transistor link to each other, and battery power input end and second field effect transistor link to each other, and the source electrode of first field effect transistor and the source electrode of second field effect transistor link to each other, as the output of power selection circuit; the first field effect transistor is connected with the first resistor and is connected with the input end of the battery power supply through the third resistor; the second field effect transistor is connected with the second resistor, the main power supply input end is connected with the second field effect transistor through the switch, two paths of power supplies are selected by adopting simple components, priority is provided, a charging function can be selected according to the type of the battery, control is simple, the design of a power supply selection circuit is simplified, and scheme cost is reduced.
The embodiment of the utility model provides a power selection circuit is provided again, including main power input end and battery power input end, main power input end and first field effect transistor link to each other, and battery power input end and second field effect transistor link to each other, the source electrode of first field effect transistor and the source electrode of second field effect transistor link to each other, as the output of power selection circuit; the first field effect transistor is connected with a first resistor and is connected with the input end of the battery power supply through a third resistor;
the second field effect transistor is connected with the second resistor, and the main power supply input end is connected with the second field effect transistor through the switch.
Specifically, the first field effect transistor and the second field effect transistor are both P-MOS, the diode is a differential pressure diode, and the switch is a key switch.
Specifically, the main power input end is connected with a drain electrode of the first field effect transistor, and the battery power input end is connected with a drain electrode of the second field effect transistor.
Specifically, the grid electrode of the first field effect transistor is connected with the ground through a first resistor, and the grid electrode of the first field effect transistor is connected with the battery power supply input end through a third resistor.
Specifically, the grid electrode of the second field effect transistor is connected with the ground through a second resistor, and the main power supply input end is connected with the grid electrode of the second field effect transistor through a switch.
Specifically, the main power input end is connected with the positive end of a diode, and the negative end of the diode is connected with the source electrode of the first field effect transistor.
As shown in fig. 1, input VIN1 is generally connected to a main input power source, input VIN2 is generally connected to a battery input, sources S of Q1 and Q2 are connected together as an output VOUT, gate G is grounded through a resistor R, drain D of Q1 is connected to input VIN1, drain D of Q2 is connected to input VIN2, input VIN1 is connected to gate G of Q2 through a switch SW1, and input VIN2 is connected to gate G of Q1 through a switch SW 1.
In a specific implementation process, 1, when only VIN1 is input, a gate G of Q1 is grounded through R, a power supply passes through a Q1 body diode, so that Q1 is turned on, at this time, VIN1 is output to VOUT, and Q1 is in a conducting state, so that consumption is extremely low; VIN1 is conducted through SW1 to Q2 gate G, Q2 is off, preventing VOUT from flowing back to VIN 2.
2. When only VIN2 is input, the grid G of Q2 is grounded through R, the power supply passes through the Q2 body diode, the Q2 is conducted, at the moment, VIN2 is output to VOUT, and Q2 is in a conducting state, so that the consumption is extremely low; VIN2 is conducted through R1 to Q1 gate G, Q1 is off, preventing VOUT from flowing back to VIN 1.
3. When VIN1 and VIN2 are input simultaneously and VIN2 does not need to be charged, when the voltages of VIN2 are close to each other, as analyzed above, Q1 and Q2 are turned off, and at the same time, the output VOUT is provided by the main input VIN1 through the low-dropout diode D1, when the voltage of the battery input VIN2 is insufficient, the partial voltage of the output VOUT on R and R1 is insufficient, so that Q1 is turned off, Q1 is turned on, VOUT is directly provided by the main input VIN1, and during the period, SW1 is always in a closed state, and VOUT does not flow back to VIN 2; if VIN2 needs to be charged, SW1 can be selectively turned off to turn on Q2, and VIN1 provides charging power through low dropout diode D1.
The utility model discloses only adopt P-MOS, the low dropout diode, realize the power selection and the function of the selection of charging in the circuit that switch and resistance device constitute, provide preferential input selection in double-input power supply circuit, the system can normally export when any input of two inputs is alone input, and two way inputs are kept apart each other, can not switch on, when two way simultaneous inputs, can have preferential input channel to provide the output, and two the tunnel can not intercommunicate, only when needs charge, can have preferential input channel to provide the power for another passageway, accomplish the input of charging.
The embodiment of the utility model provides a power selection circuit, including main power input end and battery power input end, main power input end and first field effect transistor link to each other, and battery power input end and second field effect transistor link to each other, and the source electrode of first field effect transistor and the source electrode of second field effect transistor link to each other, as the output of power selection circuit; the first field effect transistor is connected with the first resistor and is connected with the input end of the battery power supply through the third resistor; the second field effect transistor is connected with the second resistor, the main power supply input end is connected with the second field effect transistor through the switch, two paths of power supplies are selected by adopting simple components, priority is provided, a charging function can be selected according to the type of the battery, control is simple, the design of a power supply selection circuit is simplified, and scheme cost is reduced.
The utility model also provides a power supply unit, include power selection circuit.
The embodiment of the utility model provides a power supply unit, including main power input end and battery power input end, main power input end and first field effect transistor link to each other, and battery power input end and second field effect transistor link to each other, and the source electrode of first field effect transistor and the source electrode of second field effect transistor link to each other, as the output of power selection circuit; the first field effect transistor is connected with the first resistor and is connected with the input end of the battery power supply through the third resistor; the second field effect transistor is connected with the second resistor, the main power supply input end is connected with the second field effect transistor through the switch, two paths of power supplies are selected by adopting simple components, priority is provided, a charging function can be selected according to the type of the battery, control is simple, the design of a power supply selection circuit is simplified, and scheme cost is reduced.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (9)
1. A power supply selection circuit is characterized by at least comprising a main power supply input end and a battery power supply input end, wherein the main power supply input end is connected with a first field effect transistor, the battery power supply input end is connected with a second field effect transistor, and a source electrode of the first field effect transistor is connected with a source electrode of the second field effect transistor and serves as an output end of the power supply selection circuit; the first field effect transistor is connected with a first resistor and is connected with the input end of the battery power supply through a third resistor;
the second field effect transistor is connected with the second resistor, and the main power supply input end is connected with the second field effect transistor through the switch.
2. The power supply selection circuit of claim 1, wherein the main power supply input is connected to the drain of a first fet and the battery power supply input is connected to the drain of a second fet.
3. The power supply selection circuit of claim 1, wherein the gate of the first fet is coupled to ground through a first resistor, and the gate of the first fet is coupled to the battery power supply input through a third resistor.
4. The power selection circuit of claim 1, wherein the gate of the second fet is coupled to ground through a second resistor, and the main power input is coupled to the gate of the second fet through a switch.
5. The power supply selection circuit according to claim 1, wherein the main power supply input terminal is connected to a positive terminal of a diode, and a negative terminal of the diode is connected to a source of the first field effect transistor.
6. The power selection circuit of claim 1, wherein the switch is a push button switch.
7. The power selection circuit of claim 1, wherein the first fet and the second fet are both P-MOS.
8. The power supply selection circuit of claim 5, wherein the diode is a differential voltage diode.
9. A power supply device comprising the power supply selection circuit of any one of claims 1-8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120508648.5U CN215185908U (en) | 2021-03-10 | 2021-03-10 | Power supply selection circuit and power supply equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120508648.5U CN215185908U (en) | 2021-03-10 | 2021-03-10 | Power supply selection circuit and power supply equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215185908U true CN215185908U (en) | 2021-12-14 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120508648.5U Active CN215185908U (en) | 2021-03-10 | 2021-03-10 | Power supply selection circuit and power supply equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN215185908U (en) |
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2021
- 2021-03-10 CN CN202120508648.5U patent/CN215185908U/en active Active
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