CN202363961U - Circuit for switching primary/secondary power supply of USB (Universal Serial Bus) device - Google Patents
Circuit for switching primary/secondary power supply of USB (Universal Serial Bus) device Download PDFInfo
- Publication number
- CN202363961U CN202363961U CN2011204423914U CN201120442391U CN202363961U CN 202363961 U CN202363961 U CN 202363961U CN 2011204423914 U CN2011204423914 U CN 2011204423914U CN 201120442391 U CN201120442391 U CN 201120442391U CN 202363961 U CN202363961 U CN 202363961U
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- China
- Prior art keywords
- power supply
- circuit
- resistance
- usb
- usb device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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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
- 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
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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
Abstract
The utility model discloses a circuit for switching primary/secondary power supply of a USB (Universal Serial Bus) device. The circuit comprises a primary power supply circuit, a secondary power supply circuit and a judging module, wherein a primary power supply in the primary power supply circuit supplies power to the USB device via a user circuit; a USB power supply in the secondary power supply circuit supplies power to the USB device via a switch module; the primary power supply is connected with an input end of the judging module; an output end of the judging module is connected with a control signal input end of the switch module; and the judging module inputs a control signal of power-on to the switch module only when the primary power supply has no voltage signal. The circuit for switching the primary/secondary power supply of the USB device, provided by the utility model, is low in cost, simple in principle and convenient to embed; in use, only the USB power supply and the primary power supply need to be accessed into corresponding pins, and an output end of the primary power supply circuit and the secondary power supply circuit are combined together; in addition, a chip package used in the circuit is small.
Description
Technical field
The utility model relates to USB device power supply field, relates in particular to a kind of usb host as auxiliary power, in the switched circuit of other power supplys as main power source.
Background technology
Along with the development of technology, computer is rapidly popularized, and also therefore the usb host supply power mode obtains general approval, but the power supply distance of usb host is limited, is not having usb host or equipment apart from usb host when distant, and the USB power supply seems that then limitation is arranged.Abandon the usb host power supply this moment, adopt other modes to supply power to guarantee that the equipment operate as normal seems particularly important.Yet in present commutation circuit, what the use power supply control chip brought is the remarkable increase of cost; Simply use the P channel mosfet then can not overcome the influence that the bulk-effect diode of MOSFET can bring the USB device power supply monitoring as the switching controls chip; At this moment; When if duplicate supply is supplied power simultaneously; USB device MAC then can not normally detect the decline that usb host breaks off voltage on the USB power line that is brought, and also just can corresponding error not handle, and makes system undesired.
The utility model content
The utility model has overcome power supply control chip and has cost dearly, and simple MOSFET circuit does not satisfy the shortcoming of USB device to the monitoring of USB power line voltage, provides a kind of cheapness simple and satisfy the commutation circuit of USB device to the monitoring of USB power line voltage.
Technology below the utility model technical solution problem adopts realizes:
The circuit that a kind of USB device major-minor power supply switches; Comprise main power supply circuits, main power source is supplied power to USB device through subscriber line circuit in these main power supply circuits, is provided with secondary power supply circuits; The USB power supply is supplied power to USB device through switch module in these pair power supply circuits; Be provided with judge module, described main power source inserts the input of this judge module, and the output of this judge module inserts the signal input end of described switch module; When having only main power source no-voltage signal, described judge module is just to switch module input control of turning signal.
Described subscriber line circuit is a prior art, can be circuit such as transducer, is used for output with main power source and converts into and meet the power supply signal that USB device requires.
The opening and closing of described switch module all are controlled by described judge module, and as a kind of execution mode, described judge module is the not gate logic module, is used to produce NOT logic; When having only main power source no-voltage signal like this, the not gate logic module is just to switch module input control of turning signal, otherwise switch module is in dissengaged positions, promptly only supplies power to USB device through main power source.
As preferably, the power input of described USB device is provided with the afterflow module that is used for stable power-supplying when main power source and USB power supply switch.Described afterflow module can be various freewheeling circuits or several parallelly connected electric capacity.
Described not gate logic module can be existing not circuit or switch triode circuit etc.
As a kind of execution mode, described not gate logic module comprises triode Q1, resistance R 1, resistance R 2, resistance R 3, resistance R 4 and resistance R 5; The emitter of wherein said triode Q1 connects the USB power supply, and emitter is also through resistance R 5 ground connection, and the collector electrode of triode Q1 is through resistance R 4 ground connection, and collector electrode also inserts the signal input end of described switch module; Described main power source connects the base stage of triode Q1 successively through resistance R 1, resistance R 2, pass through resistance R 3 ground connection between resistance R 1 and the resistance R 2.
Described switch module can be various power control switch, for example adopts mains switch TPS2051.
The circuit cost that the utility model USB device major-minor power supply switches is low, and principle is simple, is convenient to embed, and only need USB power supply and main power source be linked into corresponding pin, and the output of main power supply circuits is also got final product with secondary power supply circuits together.In addition the Chip Packaging of using smaller, single face only needs 1.5 * 1.5CM
2Can this circuit be embedded among the PCB.
Description of drawings
Fig. 1 is the theory diagram of the utility model circuit;
Fig. 2 is the physical circuit figure of the utility model circuit.
Embodiment
Referring to Fig. 1, the circuit that a kind of USB device major-minor of the utility model power supply switches comprises main power supply circuits, and main power source VMain supplies power to USB device (among the figure+5V place) through subscriber line circuit in these main power supply circuits.
Be provided with secondary power supply circuits, USB power supply VBUS supplies power to USB device through switch module in these pair power supply circuits.
Be provided with judge module; Main power source inserts the input of this judge module; The output of this judge module inserts the signal input end of switch module, and when having only main power source VMain no-voltage signal, judge module is just to switch module input control of turning signal; Otherwise switch module is in dissengaged positions, promptly only supplies power to USB device through main power source VMain.
The power input of USB device is provided with the afterflow module that is used for stable power-supplying when main power source and the switching of USB power supply.
The utility model physical circuit can be referring to Fig. 2, and main power source VMain forms simple not gate through positive-negative-positive triode Q1 (S9012) provides enabling of switch for switch module U1 (TPS2051BDBV) later on.
USB power supply VBUS inserts the power input of switch module U1, and the power output end of switch module U1 connects USB device.
Be provided with triode Q1, its emitter connects USB power supply VBUS, and emitter is also through resistance R 5 (10K) ground connection.
The collector electrode of triode Q1 is through resistance R 4 (10K) ground connection, and collector electrode also inserts the signal input end of switch module U1.
Main power source VMain connects the base stage of triode Q1 successively through resistance R 1, resistance R 2 (10K), pass through resistance R 3 ground connection between resistance R 1 and the resistance R 2; Main power source VMain also supplies power to USB device through subscriber line circuit.
The afterflow module i.e. the capacitor C 2 (330uF/25V) and capacitor C 1 (0.1uF) end ground connection of parallel connection, and the other end inserts the power input of USB device.
Among Fig. 2, (R3/ (R1+R3)) * VMain ≈ VBUS.
(1) when USB power supply VBUS power supply is only arranged; The emitter of triode Q1 among Fig. 2 (the 2nd pin) is in high level, base stage (the 1st pin) because the effect of resistance R 2, resistance R 3 is in low level, and this moment, triode Q1 was saturated, makes collector electrode (the 3rd pin) the voltage U 3 ≈ VBUS of triode Q1; That is: high level; Thereby make switch module open, the input of USB power supply VBUS and USB device (+5V) be communicated with, promptly supply power through secondary power supply circuits.
(2) when main power source VMain power supply is only arranged; The emitter of triode Q1 among Fig. 2 (the 2nd pin) is because the effect of resistance R 5 is in low level, base stage (the 1st pin) because the dividing potential drop of resistance R 1, resistance R 3 is in high level; This moment, triode Q1 ended; Make collector electrode (the 3rd pin) the voltage U 3=0 of triode Q1, that is: low level, thus make switch module close; USB power supply VBUS and USB device input (+5V) breaking off, the USB device input is then supplied power by the main power supply circuits at subscriber line circuit place.
(3) when main power source VMain and USB power supply VBUS supply power simultaneously; The emitter of triode Q1 among Fig. 2 (the 2nd pin) is in high level, base stage (the 1st pin) because the dividing potential drop of resistance R 1, resistance R 2 is in high level; This moment, triode Q1 ended, and made collector electrode (the 3rd pin) voltage U 3=0, that is: the low level of triode Q1; Thereby make switch module close, USB power supply VBUS and USB device input (+5V) break off.
(4) under (3) kind situation, if break off the power supply on the USB power supply VBUS, circuit gets into (2) kind situation, and USB power supply VBUS is simultaneously because the effect of resistance R 5 makes the USB power supply VBUS low level of coming in and going out.The user can detect the change in voltage on the USB power supply VBUS naturally.
(5) under (3) kind situation, if break off the power supply on the main power source VMain, circuit gets into (1) kind situation.
(6) (4), in (5) during situation, the afterflow module then plays the effect of afterflow, voltage stabilizing, filtering in handoff procedure.
The circuit cost that the utility model USB device major-minor power supply switches is low, and principle is simple, is convenient to embed, and only need USB power supply and main power source be linked into corresponding pin, and the output of main power supply circuits is also got final product with secondary power supply circuits together.
Claims (5)
1. the circuit that USB device major-minor power supply switches comprises main power supply circuits, and main power source is supplied power to USB device through subscriber line circuit in these main power supply circuits; It is characterized in that; Be provided with secondary power supply circuits, the USB power supply is supplied power to USB device through switch module in these pair power supply circuits, is provided with judge module; Described main power source inserts the input of this judge module; The output of this judge module inserts the signal input end of described switch module, and when having only main power source no-voltage signal, described judge module is just to switch module input control of turning signal.
2. the circuit that USB device major-minor power supply as claimed in claim 1 switches is characterized in that, the power input of described USB device is provided with the afterflow module that is used for stable power-supplying when main power source and the switching of USB power supply.
3. the circuit that USB device major-minor power supply as claimed in claim 2 switches is characterized in that described afterflow module is several parallelly connected electric capacity.
4. the circuit that USB device major-minor power supply as claimed in claim 3 switches is characterized in that described judge module is the not gate logic module.
5. the circuit that USB device major-minor power supply as claimed in claim 4 switches is characterized in that described not gate logic module comprises triode Q1, resistance R 1, resistance R 2, resistance R 3, resistance R 4 and resistance R 5;
The emitter of wherein said triode Q1 connects the USB power supply, and emitter is also through resistance R 5 ground connection, and the collector electrode of triode Q1 is through resistance R 4 ground connection, and collector electrode also inserts the signal input end of described switch module;
Described main power source connects the base stage of triode Q1 successively through resistance R 1, resistance R 2, pass through resistance R 3 ground connection between resistance R 1 and the resistance R 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204423914U CN202363961U (en) | 2011-11-10 | 2011-11-10 | Circuit for switching primary/secondary power supply of USB (Universal Serial Bus) device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204423914U CN202363961U (en) | 2011-11-10 | 2011-11-10 | Circuit for switching primary/secondary power supply of USB (Universal Serial Bus) device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202363961U true CN202363961U (en) | 2012-08-01 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011204423914U Expired - Fee Related CN202363961U (en) | 2011-11-10 | 2011-11-10 | Circuit for switching primary/secondary power supply of USB (Universal Serial Bus) device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202363961U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111224657A (en) * | 2019-12-25 | 2020-06-02 | 曙光信息产业(北京)有限公司 | Power supply switching circuit of computer USB port |
-
2011
- 2011-11-10 CN CN2011204423914U patent/CN202363961U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111224657A (en) * | 2019-12-25 | 2020-06-02 | 曙光信息产业(北京)有限公司 | Power supply switching circuit of computer USB port |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120801 Termination date: 20141110 |
|
| EXPY | Termination of patent right or utility model |