CN213027525U - Power supply switching circuit - Google Patents
Power supply switching circuit Download PDFInfo
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- CN213027525U CN213027525U CN202021428759.7U CN202021428759U CN213027525U CN 213027525 U CN213027525 U CN 213027525U CN 202021428759 U CN202021428759 U CN 202021428759U CN 213027525 U CN213027525 U CN 213027525U
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- mos pipe
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Abstract
The utility model is suitable for a power switching field provides a power switching circuit, the base of triode connects USB power supply interface and passes through second resistance ground connection through first resistance respectively, the projecting pole ground connection of triode, the grid of first MOS pipe is connected to the collecting electrode of triode, the indirect third resistance of source electrode and grid of first MOS pipe, the source electrode of first MOS pipe connects battery power supply interface, the drain electrode of first MOS pipe connects the grid of second MOS pipe, the grid of second MOS pipe passes through fourth resistance ground connection, the source electrode of second MOS pipe connects battery power supply interface, the drain electrode of second MOS pipe connects electronic equipment's power end, the USB power supply interface is connected to the positive pole of diode, electronic equipment's power end is connected to the negative pole of diode. The power supply switching circuit can cut off the power supply of the battery in time when the USB supplies power, avoids causing safety accidents, and has small static current ratio and can delay the service time of the battery as much as possible when the battery works normally.
Description
Technical Field
The utility model belongs to the power field especially relates to a power supply switching circuit.
Background
The output voltage of two batteries used by the electronic equipment is 6-8.4V, when the electric quantity of the batteries is insufficient, the electronic equipment needs to carry out emergency power supply through the USB power supply interface, but the lowest voltage of the batteries is still higher than the power supply voltage of the USB interface, so that the power supply of the batteries needs to be cut off when the power supply is carried out through the USB interface. In addition, the user may mistakenly use the USB interface to supply power when the battery is sufficiently charged. In the above two situations, if the battery power is not cut off, the power supply failure of the USB interface may be caused, or other accidents may be caused.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a power supply switching circuit, when aiming at solving battery power not enough and need to pass through the power supply of USB interface, perhaps battery power is sufficient but during wrong use USB interface power supply, does not cut off the power supply of battery, probably causes the problem of USB interface power supply failure or initiation accident.
The utility model provides a power supply switching circuit, include: the power supply device comprises a USB power supply interface, a battery power supply interface, a power supply end of electronic equipment, a first MOS (metal oxide semiconductor) tube, a second MOS tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a triode and a diode;
the base of triode connects USB power supply interface and through second resistance ground connection respectively through first resistance, the projecting pole ground connection of triode, the grid of first MOS pipe is connected to the collecting electrode of triode, the indirect third resistance between the source electrode of first MOS pipe and the grid, the battery power supply interface is connected to the source electrode of first MOS pipe, the grid of second MOS pipe is connected to the drain electrode of first MOS pipe, the grid of second MOS pipe is through fourth resistance ground connection, the battery power supply interface is connected to the source electrode of second MOS pipe, the drain electrode of second MOS pipe connects the power end of electronic equipment, USB power supply interface is connected to the positive pole of diode, the power end of electronic equipment is connected to the negative pole of diode.
Further, the power supply switching circuit further comprises a first capacitor connected between the drain electrode and the gate electrode of the first MOS transistor.
Further, the power supply switching circuit further comprises a second capacitor connected between the gate and the source of the second MOS transistor.
Further, the power supply switching circuit further comprises a third capacitor connected between the gate and the drain of the second MOS transistor.
The utility model discloses in, when the power supply of USB power supply interface, the triode switches on, and first MOS pipe switches on, and the second MOS pipe can not switch on, and the USB power supply interface communicates electronic equipment's power end VDD through diode D1, can in time cut off the power supply of battery, avoids causing the incident, and at the battery normal during operation, and quiescent current ratio is less, can postpone the live time of battery as far as possible.
Drawings
Fig. 1 is a schematic diagram of a power switching circuit according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of another power switching circuit according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more clearly understood, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In order to explain the technical solution of the present invention, the following description is made by using specific examples.
Referring to fig. 1, an embodiment of the present invention provides a power switching circuit, including:
USB power supply interface VUSBBattery power supply interface VBATThe power supply terminal VDD of the electronic device, a first MOS transistor Q1, a second MOS transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a triode Q3 and a diode D1;
the base electrodes of the triode Q3 are respectively connected with the USB power supply interface V through a first resistor R1USBThe second resistor R2 is connected to the ground, the emitter of the transistor Q3 is connected to the ground, the collector of the transistor Q3 is connected to the grid of the first MOS transistor Q1, and the source and the grid of the first MOS transistor Q1An indirect third resistor R3, the source of the first MOS transistor Q1 is connected with a battery power supply interface VBATThe drain of the first MOS transistor Q1 is connected to the gate of the second MOS transistor Q2, the gate of the second MOS transistor Q2 is grounded through a fourth resistor R4, and the source of the second MOS transistor Q2 is connected to the battery power supply interface VBATThe drain of the second MOS transistor Q2 is connected to the power supply terminal VDD of the electronic device, and the anode of the diode D1 is connected to the USB power supply interface VUSBThe cathode of the diode D1 is connected to the power supply terminal VDD of the electronic device.
In an embodiment of the present invention, the power switching circuit may further include a first capacitor connected between the drain and the gate of the first MOS transistor.
In an embodiment of the present invention, the power switching circuit may further include a second capacitor connected between the gate and the source of the second MOS transistor.
In an embodiment of the present invention, the power switching circuit may further include a third capacitor connected between the gate and the drain of the second MOS transistor, please refer to fig. 2 specifically.
The working principle of the circuit is as follows:
under normal conditions, the USB power supply interface VUSBWhen no power is supplied, the base electrode level of the triode Q3 is zero and is not conducted; the grid voltage of the first MOS tube Q1 is pulled up to VBATVGS is zero, and the first MOS tube Q1 is not conducted; the grid electrode of the second MOS tube Q2 is grounded, the-VGS is larger than zero, the second MOS tube Q2 is normally conducted, and the power supply end VDD of the electronic device is a battery power supply interface VBATProvided is a method.
USB power supply interface VUSBWhen power supply is started, the triode Q3 is conducted, the collector is grounded, the grid level of the first MOS transistor Q1 is zero, VGS is larger than zero, and the first MOS transistor Q1 is conducted; this in turn causes the gate voltage of the second MOS transistor Q2 to be pulled up to VBATThe second MOS transistor Q2 cannot be turned on. USB power supply interface VUSBThe emergency power supply is realized by the diode D1 being connected to the power supply terminal VDD of the electronic device.
The embodiment of the utility model provides an in, when the power supply of USB power supply interface, the triode switches on, and first MOS pipe switches on, and the second MOS pipe can not switch on, and the USB power supply interface communicates electronic equipment's power end VDD through diode D1, can in time cut off the power supply of battery, avoids causing the incident, and when the battery normally worked, static current ratio is less, can postpone the live time of battery as far as possible.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.
Claims (4)
1. A power switching circuit, comprising: the power supply device comprises a USB power supply interface, a battery power supply interface, a power supply end of electronic equipment, a first MOS (metal oxide semiconductor) tube, a second MOS tube, a first resistor, a second resistor, a third resistor, a fourth resistor, a triode and a diode;
the base of triode connects USB power supply interface and through second resistance ground connection respectively through first resistance, the projecting pole ground connection of triode, the grid of first MOS pipe is connected to the collecting electrode of triode, the indirect third resistance between the source electrode of first MOS pipe and the grid, the battery power supply interface is connected to the source electrode of first MOS pipe, the grid of second MOS pipe is connected to the drain electrode of first MOS pipe, the grid of second MOS pipe is through fourth resistance ground connection, the battery power supply interface is connected to the source electrode of second MOS pipe, the drain electrode of second MOS pipe connects the power end of electronic equipment, USB power supply interface is connected to the positive pole of diode, the power end of electronic equipment is connected to the negative pole of diode.
2. The power switching circuit of claim 1, further comprising a first capacitor connected between the drain and the gate of the first MOS transistor.
3. The power switching circuit of claim 1, further comprising a second capacitor connected between the gate and the source of the second MOS transistor.
4. The power switching circuit according to any one of claims 1 to 3, further comprising a third capacitor connected between the gate and the drain of the second MOS transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021428759.7U CN213027525U (en) | 2020-07-20 | 2020-07-20 | Power supply switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021428759.7U CN213027525U (en) | 2020-07-20 | 2020-07-20 | Power supply switching circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213027525U true CN213027525U (en) | 2021-04-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202021428759.7U Active CN213027525U (en) | 2020-07-20 | 2020-07-20 | Power supply switching circuit |
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| CN (1) | CN213027525U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113316381A (en) * | 2021-04-23 | 2021-08-27 | 山东英信计算机技术有限公司 | Printed circuit mother board and printed circuit board assembly |
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2020
- 2020-07-20 CN CN202021428759.7U patent/CN213027525U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113316381A (en) * | 2021-04-23 | 2021-08-27 | 山东英信计算机技术有限公司 | Printed circuit mother board and printed circuit board assembly |
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