CN109038799B - Circuit for preventing double power supply switching from generating electric leakage and electronic device - Google Patents

Circuit for preventing double power supply switching from generating electric leakage and electronic device Download PDF

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Publication number
CN109038799B
CN109038799B CN201810872227.3A CN201810872227A CN109038799B CN 109038799 B CN109038799 B CN 109038799B CN 201810872227 A CN201810872227 A CN 201810872227A CN 109038799 B CN109038799 B CN 109038799B
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Prior art keywords
power supply
module
switching
switch module
field effect
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CN201810872227.3A
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CN109038799A (en
Inventor
谢唯盟
杨政颖
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Hefei Lianbao Information Technology Co Ltd
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Hefei Lianbao Information Technology Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • 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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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electronic Switches (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

The application provides a circuit and an electronic device for preventing leakage caused by dual power supply switching, wherein the circuit comprises: the switching device comprises a first power supply module, a second power supply module, a first switch module, a second switch module and a switching module; a second switch module for performing an on or off operation according to a signal of a control pin of the first power supply module; one end of the second power supply module is connected with the output current end of the second switch module, and the other end of the second power supply module is the front end of the second power supply module; the first switch module is used for executing on-off operation according to the switching signal of the switching module; the switching module sends a switching signal to a third end of the first switching module according to the signal of the control end; the signal at the control terminal is associated with the current output of the first power supply module. The problem of same circuit's USB type-c interface power module and power adapter power module produce the electric leakage because of switching power module is solved.

Description

Circuit for preventing double power supply switching from generating electric leakage and electronic device
Technical Field
The application relates to the field of electronics, in particular to a circuit for preventing leakage caused by dual-power switching and an electronic device.
Background
Nowadays, electronic devices are getting more and more weight in our lives, and all electronic products are kept away from interfaces, and more USB type-c interfaces are being applied, both on mobile phones and on computers.
The advantage of USB type-c interface is: the USB interface has the advantages of small volume, capability of supporting the function of 'forward and reverse insertion' which can be inserted from both the front and the back sides, high transmission speed and accordance with the standard of USB 3.1.
Before the USB type-c interface appears, either the phone or the computer is powered alone. Since the appearance of the USB type-c interface, an electronic device has emerged that can be powered through both the USB type-c interface and through a common power adapter. The two power supply modes of the electronic equipment can be used in parallel, but the problem of electric leakage exists when the power supply is switched.
Disclosure of Invention
The application provides a circuit for preventing leakage caused by dual power supply switching and an electronic device; the USB type-c interface power supply module and the power adapter power supply module of the same circuit are used for simultaneously supplying power to the outside, and the problem of electric leakage caused by switching the power supply modules is solved.
In order to solve the technical problems, the embodiment of the application provides the following technical scheme:
The application provides a circuit for preventing leakage caused by dual power supply switching, which comprises: the switching device comprises a first power supply module, a second power supply module, a first switch module, a second switch module and a switching module;
One end of the second switch module is connected with the first switch module, the other end of the second switch module is an output current end, and the third end of the second switch module is connected with a control pin of the first power supply module and is used for executing on-off operation according to signals of the control pin of the first power supply module;
one end of the second power supply module is connected with the output current end of the second switch module, and the other end of the second power supply module is the front end of the second power supply module;
The other end of the first switch module is connected with the first power supply module, and the third end of the first switch module is connected with the switching module and is used for executing on-off operation according to a switching signal of the switching module;
One end of the switching module is connected between the first switching module and the second switching module, the other end of the switching module is connected with the third end of the first switching module, the third end of the switching module is connected with the control end, and the switching module sends a switching signal to the third end of the first switching module according to the signal of the control end;
The signal at the control terminal is associated with the current output of the first power supply module.
Optionally, the switching module includes a bipolar junction transistor;
the emitter of the bipolar junction transistor is connected between the first switch module and the second switch module, the collector of the bipolar junction transistor is connected with the third end of the first switch module, and the bipolar junction transistor is used for outputting low voltage to the base electrode of the bipolar junction transistor when entering the second state, so that the collector and the emitter are conducted, and an off signal is sent to the third end of the first switch module; the first state refers to a state that the first power supply module and the second power supply module are in a power supply state; the second state refers to that the first power supply module exits the power supply state after the first state.
Further, the control end at least includes: the first resistor, the second resistor, the third resistor and the depletion type N-channel field effect transistor;
One end of the first resistor is connected with the base electrode of the bipolar junction transistor, and the other end of the first resistor is connected with the drain electrode of the depletion type N-channel field effect transistor;
The source electrode of the depletion-type N-channel field effect transistor is grounded, and the grid electrode of the depletion-type N-channel field effect transistor is connected with one end of the second resistor;
The other end of the second resistor is connected with the front end of the second power supply module;
And one end of the third resistor is connected between the second resistor and the grid electrode of the depletion type N-channel field effect transistor, and the other end of the third resistor is grounded.
Optionally, the first switch module includes an enhanced P-channel field effect transistor of a first parasitic diode and a fourth resistor;
The source electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the first switch module, the drain electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the first power supply module, and the grid electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the emitter electrode of the bipolar junction transistor of the switch module;
And one end of the fourth resistor is connected with the grid electrode of the enhanced P-channel field effect transistor of the first parasitic diode, and the other end of the fourth resistor is grounded.
Optionally, the second switch module includes an enhanced P-channel field effect transistor of a second parasitic diode;
And the source electrode of the enhanced P-channel field effect transistor of the second parasitic diode is connected with the first switch module, the drain electrode of the enhanced P-channel field effect transistor is an output current end, and the grid electrode of the enhanced P-channel field effect transistor is connected with the control pin of the first power supply module.
In summary, the second power supply module adopts the power adapter to convert ac into dc.
In summary, the first power supply module uses the USB type-c interface as the power supply interface.
The application provides an electronic device, which comprises a device main body and a circuit for preventing electric leakage generated by switching of dual power supplies,
Further, the circuit for preventing the leakage generated by the switching of the dual power supply is arranged in the shell of the device main body.
Based on the disclosure of the above embodiments, it can be known that the embodiments of the present application have the following beneficial effects:
The application provides a circuit and an electronic device for preventing leakage caused by dual power supply switching, wherein the circuit comprises: the switching device comprises a first power supply module, a second power supply module, a first switch module, a second switch module and a switching module; one end of the second switch module is connected with the first switch module, the other end of the second switch module is an output current end, and the third end of the second switch module is connected with a control pin of the first power supply module and is used for executing on-off operation according to signals of the control pin of the first power supply module; one end of the second power supply module is connected with the output current end of the second switch module, and the other end of the second power supply module is the front end of the second power supply module; the other end of the first switch module is connected with the first power supply module, and the third end of the first switch module is connected with the switching module and is used for executing on-off operation according to a switching signal of the switching module; one end of the switching module is connected between the first switching module and the second switching module, the other end of the switching module is connected with the third end of the first switching module, the third end of the switching module is connected with the control end, and the switching module sends a switching signal to the third end of the first switching module according to the signal of the control end; the signal at the control terminal is associated with the current output of the first power supply module. The problem of same circuit USB type-c interface power module and power adapter power module when to external simultaneous power supply, because of switching power module and produce the electric leakage is solved.
Drawings
FIG. 1 is a schematic diagram of a power supply circuit of a power adapter for generating leakage through dual power switching according to an embodiment of the present application;
FIG. 2 is a schematic diagram of a USB type-c interface power supply circuit for generating leakage by dual power switching according to an embodiment of the present application;
FIG. 3 is a graph showing the measurement result of leakage generated by switching between dual power supplies according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a module for preventing leakage caused by dual power switching according to an embodiment of the present application;
FIG. 5 is a schematic diagram of a circuit for preventing leakage caused by dual power switching according to an embodiment of the present application;
fig. 6 is a diagram of measurement results for preventing leakage caused by switching between dual power supplies according to an embodiment of the present application.
Description of the reference numerals
The power supply system comprises a 1-first power supply module, a 2-second power supply module, a 3-first switch module, a 4-second switch module, a 5-switching module, a 6-output current end, a 7-control end and a front end of an 8-second power supply module;
31-an enhanced P-channel field effect transistor of a first parasitic diode, 32-a fourth resistor;
41-an enhancement P-channel field effect transistor of a second parasitic diode;
a 51-bipolar junction transistor;
71-first resistor, 72-second resistor, 73-third resistor, 74-depletion N-channel FET.
Detailed Description
Hereinafter, specific embodiments of the present application will be described in detail with reference to the accompanying drawings, but not limiting the application.
It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be taken as limiting, but merely as exemplification of the embodiments. Other modifications within the scope and spirit of the application will occur to persons of ordinary skill in the art.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with a general description of the application given above, and the detailed description of the embodiments given below, serve to explain the principles of the application.
These and other characteristics of the application will become apparent from the following description of a preferred form of embodiment, given as a non-limiting example, with reference to the accompanying drawings.
It is also to be understood that, although the application has been described with reference to some specific examples, a person skilled in the art will certainly be able to achieve many other equivalent forms of the application, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
The above and other aspects, features and advantages of the present application will become more apparent in light of the following detailed description when taken in conjunction with the accompanying drawings.
Specific embodiments of the present application will be described hereinafter with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely exemplary of the application, which can be embodied in various forms. Well-known and/or repeated functions and constructions are not described in detail to avoid obscuring the application in unnecessary or unnecessary detail. Therefore, specific structural and functional details disclosed herein are not intended to be limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present application in virtually any appropriately detailed structure.
The specification may use the word "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may each refer to one or more of the same or different embodiments in accordance with the application.
The application provides a circuit for preventing leakage caused by dual power supply switching; the application also provides an electronic device. The following examples are described in detail one by one.
The first embodiment of the present application, namely, an embodiment of a circuit for preventing leakage caused by switching between dual power supplies, is provided. Fig. 1 is a schematic diagram of a power supply circuit of a power adapter for generating leakage through dual power supply switching according to an embodiment of the present application; FIG. 2 is a schematic diagram of a USBtype-c interface power supply circuit for generating leakage through dual power switching according to an embodiment of the present application; FIG. 3 is a graph showing the measurement result of leakage generated by switching between dual power supplies according to an embodiment of the present application; FIG. 4 is a schematic diagram of a module for preventing leakage caused by dual power switching according to an embodiment of the present application; FIG. 5 is a schematic diagram of a circuit for preventing leakage caused by dual power switching according to an embodiment of the present application; fig. 6 is a diagram of measurement results for preventing leakage caused by switching between dual power supplies according to an embodiment of the present application.
Referring to fig. 1 and 2, the power adapter power supply circuit and the USB type-c interface power supply circuit are connected at the output current end 6. When the power adapter power supply circuit and the USB type-c interface power supply circuit are in a power supply state, the USB type-c interface is pulled out, so that the USB type-c interface power supply circuit stops supplying power. At this time, the current of the power adapter power supply circuit flows back through the parasitic diode in the parasitic diode enhanced P-channel fet 602 via the output current terminal 6. Because the gate of the parasitic diode enhanced P-channel fet 601 receives a turn-off signal later than the occurrence time of the reverse current, the reverse current flows through the parasitic diode enhanced P-channel fet 601. Thus, electric leakage occurs.
Referring to fig. 3, the upper black line represents the output voltage of the power adapter power supply circuit, and the lower black line represents the output voltage of the USB type-c interface power supply circuit. When the USB type-c interface is pulled out, and the USB type-c interface power supply circuit stops supplying power, the output voltage of the USB type-c interface power supply circuit still keeps high potential, and the occurrence of electric leakage is indicated.
Referring to fig. 4, the present embodiment provides a circuit for preventing leakage caused by switching between dual power supplies, the circuit comprising: the switching device comprises a first power supply module 1, a second power supply module 2, a first switch module 3, a second switch module 4 and a switching module 5.
And one end of the second switch module 4 is connected with the first switch module 3, the other end of the second switch module is an output current end 6, and the third end of the second switch module is connected with the control pin of the first power supply module 1 and is used for executing on-off operation according to the signal of the control pin of the first power supply module 1.
And one end of the second power supply module 2 is connected with the output current end 6 of the second switch module 4, and the other end of the second power supply module is the front end 8 of the second power supply module.
The other end of the first switch module 3 is connected with the first power supply module 1, and the third end of the first switch module is connected with the switch module 5, so as to perform on or off operation according to the switch signal of the switch module 5.
One end of the switching module 5 is connected between the first switching module 3 and the second switching module 4, the other end of the switching module 5 is connected with the third end of the first switching module 3, the third end of the switching module 5 is connected with the control end 7, and the switching module 5 sends a switching signal to the third end of the first switching module 3 according to the signal of the control end 7.
The signal of the control terminal 7 is associated with the current output of the first power supply module 1. For example, when the current of the first power supply module 1 is continuously output, the control terminal 7 sends a power supply signal, and the switching module 5 notifies the first switch module 3 to be turned on according to the power supply signal; when the current of the first power supply module 1 stops outputting, the control end 7 sends a power supply stopping signal, and the switching module 5 notifies the first switch module 3 to be disconnected according to the power supply stopping signal.
Referring to fig. 5, the switching module 5 includes a bipolar junction transistor 51.
The bipolar junction transistor (Bipolar Junction Transistor, BJT for short) is also called a semiconductor triode, which is a device combining two PN junctions together through a certain process and has a PNP and NPN combined structure. Bipolar junction transistors, externally leading to three poles: the collector, the emitter and the base, the collector is drawn out from the collector region, the emitter is drawn out from the emitter region, and the base is drawn out from the base region (the base region is in the middle).
A bipolar junction transistor 51, an emitter of which is connected between the first switch module 3 and the second switch module 4, and a collector of which is connected to the third terminal of the first switch module 3, for outputting a low voltage to the base of the bipolar junction transistor 51 when entering the second state, and further, the collector and the emitter are turned on, and sending an off signal to the third terminal of the first switch module 3; the first state refers to a state that the first power supply module 1 and the second power supply module 2 are in a power supply state; the second state refers to that the first power supply module 1 exits the power supply state after the first state.
The control terminal 7 includes: a first resistor 71, a second resistor 72, a third resistor 73, and a depletion N-channel FET 74.
The depletion type N-channel field effect transistor is called an N-channel field effect transistor which is formed by a P-type substrate and two high-concentration N diffusion regions, and an N-type conducting channel is formed between the two high-concentration N diffusion regions when the transistor is conducted. The N-channel enhancement-mode field effect transistor needs to apply a forward bias voltage to the gate, and the N-channel field effect transistor generated by the conductive channel only when the voltage between the gate and the source is greater than the threshold voltage.
The depletion type N-channel field effect transistor is an N-channel field effect transistor which has a conductive channel when the voltage between a gate and a source is zero. There are three pins: drain, gate, source.
A first resistor 71, one end of which is connected to the base of the bipolar junction transistor 51, and the other end of which is connected to the drain of the depletion type N-channel field effect transistor 74.
The source of the depletion-type N-channel field effect transistor 74 is grounded, and the gate thereof is connected to one end of the second resistor 72.
The other end of the second resistor 72 is connected to the front end 8 of the second power supply module 2.
And one end of the third resistor 73 is connected between the second resistor 72 and the grid electrode of the depletion type N-channel field effect transistor 74, and the other end of the third resistor is grounded.
The first switch module 3 includes an enhanced P-channel fet 31 and a fourth resistor 32 of a first parasitic diode.
The P-channel field effect transistor (PMOS transistor for short) refers to an N-type substrate and a P-channel field effect transistor for conveying current by the flow of holes. There are three pins: drain, gate, source.
The PMOS tube is used as a switch, and is conducted when the grid voltage is low level; when the grid voltage is at a high level, the PMOS tube is cut off.
The parasitic diode and the PMOS tube have opposite input and output directions, and when a large instant reverse current is generated in the circuit, the parasitic diode can be led out through the parasitic diode, so that the parasitic diode does not break down the PMOS tube, and plays a role in protecting the PMOS tube.
The source of the first parasitic diode is connected with the first switch module 3, the drain is connected with the first power supply module 1, and the gate is connected with the emitter of the bipolar junction transistor 51 of the switch module 5.
And one end of the fourth resistor 32 is connected with the gate of the enhanced P-channel field effect transistor 31 of the first parasitic diode, and the other end of the fourth resistor is grounded.
The second switch module 4 includes a second parasitic diode enhancement P-channel field effect transistor 41.
The source of the second parasitic diode is connected with the first switch module 3, the drain is the output current end 6, and the grid is connected with the control pin of the first power supply module 1.
The second power supply module 2 is a power supply module for converting ac to dc by using a power adapter.
The power adapter is a power supply conversion device for small portable electronic equipment and electronic appliances, and is generally composed of a housing, a power transformer and a rectifying circuit, and can be classified into an AC output type and a DC output type according to the output type. The power adapter circuit of this embodiment is the same as a conventional power adapter circuit.
The first power supply module 1 is a power supply module adopting an USB type-c interface as a power supply interface.
The current USB type-c interface is more and more commonly applied, and has the advantages that: the USB interface has the advantages of small volume, capability of supporting the function of 'forward and reverse insertion' which can be inserted from both the front and the back sides, high transmission speed and accordance with the standard of USB 3.1.
According to the embodiment of the application, the power supply adapter power supply module and the USB type-c interface power supply module are integrated together, so that the power supply means are enriched. And the user experience is improved.
Referring to fig. 6, the upper black line represents the output voltage of the power adapter power supply circuit, and the lower black line represents the output voltage of the USB type-c interface power supply circuit. When the USB type-c interface is pulled out, and the USB type-c interface power supply circuit stops supplying power, the output voltage of the USB type-c interface power supply circuit is reduced from high potential to low potential, so that no leakage phenomenon is indicated.
The embodiment solves the problem that when the USB type-c interface power supply module and the power adapter power supply module of the same circuit supply power to the outside simultaneously, the power supply module is switched to generate electric leakage.
Corresponding to the first embodiment provided by the application, the application also provides a second embodiment, namely an electronic device. Since the second embodiment is substantially similar to the first embodiment, the description is relatively simple, and the relevant portions will be referred to the corresponding descriptions of the first embodiment. The electronic device embodiments described below are merely illustrative.
The application provides an electronic device, which comprises a device main body and the circuit for preventing the electric leakage generated by switching of dual power supplies in the first embodiment.
Further, the circuit for preventing the leakage generated by the switching of the dual power supply is arranged in the shell of the device main body.
It will be clear to those skilled in the art that, for convenience and brevity of description, the electronic device to which the above-described circuit for preventing leakage caused by dual power switching is applied may refer to the corresponding description in the first embodiment, and will not be repeated here.
The embodiment solves the problem that when the USB type-c interface power supply module and the power adapter power supply module of the same circuit supply power to the outside simultaneously, the power supply module is switched to generate electric leakage.
The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, the scope of which is defined by the claims. Various modifications and equivalent arrangements of this application will occur to those skilled in the art, and are intended to be within the spirit and scope of the application.

Claims (6)

1. A circuit for preventing leakage from a dual power supply switch, the circuit comprising:
the switching device comprises a first power supply module, a second power supply module, a first switch module, a second switch module and a switching module;
One end of the second switch module is connected with the first switch module, the other end of the second switch module is an output current end, and the third end of the second switch module is connected with a control pin of the first power supply module and is used for executing on-off operation according to signals of the control pin of the first power supply module;
one end of the second power supply module is connected with the output current end of the second switch module, and the other end of the second power supply module is the front end of the second power supply module;
The other end of the first switch module is connected with the first power supply module, and the third end of the first switch module is connected with the switching module and is used for executing on-off operation according to a switching signal of the switching module;
One end of the switching module is connected between the first switching module and the second switching module, the other end of the switching module is connected with the third end of the first switching module, the third end of the switching module is connected with the control end, and the switching module sends a switching signal to the third end of the first switching module according to the signal of the control end;
The signal of the control end is related to the current output of the first power supply module, wherein when the current of the first power supply module is continuously output, the control end sends out a power supply signal, and the switching module notifies the first switch module to be connected according to the power supply signal; when the current of the first power supply module stops outputting, the control end sends a power supply stopping signal, and the switching module informs the first switch module to be disconnected according to the power supply stopping signal;
The switching module comprises a bipolar junction transistor;
The emitter of the bipolar junction transistor is connected between the first switch module and the second switch module, the collector of the bipolar junction transistor is connected with the third end of the first switch module, and the bipolar junction transistor is used for outputting low voltage to the base electrode of the bipolar junction transistor when entering the second state, so that the collector and the emitter are conducted, and an off signal is sent to the third end of the first switch module; the second state refers to that the first power supply module exits from a power supply state after the first state; the first state refers to the first power supply module and the second power supply module being in a power supply state;
the first switch module comprises an enhanced P-channel field effect transistor of a first parasitic diode and a fourth resistor;
The source electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the first switch module, the drain electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the first power supply module, and the grid electrode of the enhanced P-channel field effect transistor of the first parasitic diode is connected with the emitter electrode of the bipolar junction transistor of the switch module;
one end of the fourth resistor is connected with the grid electrode of the enhanced P-channel field effect transistor of the first parasitic diode, and the other end of the fourth resistor is grounded;
The second switch module comprises an enhanced P-channel field effect transistor of a second parasitic diode;
And the source electrode of the enhanced P-channel field effect transistor of the second parasitic diode is connected with the first switch module, the drain electrode of the enhanced P-channel field effect transistor is an output current end, and the grid electrode of the enhanced P-channel field effect transistor is connected with the control pin of the first power supply module.
2. The circuit of claim 1, wherein the control terminal comprises at least: the first resistor, the second resistor, the third resistor and the depletion type N-channel field effect transistor;
One end of the first resistor is connected with the base electrode of the bipolar junction transistor, and the other end of the first resistor is connected with the drain electrode of the depletion type N-channel field effect transistor;
The source electrode of the depletion-type N-channel field effect transistor is grounded, and the grid electrode of the depletion-type N-channel field effect transistor is connected with one end of the second resistor;
The other end of the second resistor is connected with the front end of the second power supply module;
And one end of the third resistor is connected between the second resistor and the grid electrode of the depletion type N-channel field effect transistor, and the other end of the third resistor is grounded.
3. A circuit according to claim 1 or 2, wherein the second power supply module is a power supply module for converting ac to dc using a power adapter.
4. The circuit according to claim 1 or 2, wherein the first power supply module is a power supply module employing a USB type-c interface as a power supply interface.
5. An electronic device comprising a device body and a circuit for preventing leakage caused by switching between dual power supplies according to any one of claims 1 to 4.
6. The device of claim 5, wherein the circuit for preventing leakage from the dual power switch is disposed within a housing of the device body.
CN201810872227.3A 2018-08-02 2018-08-02 Circuit for preventing double power supply switching from generating electric leakage and electronic device Active CN109038799B (en)

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