CN206331538U - Handheld POS terminal and its USB switching circuits - Google Patents
Handheld POS terminal and its USB switching circuits Download PDFInfo
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- CN206331538U CN206331538U CN201720009841.8U CN201720009841U CN206331538U CN 206331538 U CN206331538 U CN 206331538U CN 201720009841 U CN201720009841 U CN 201720009841U CN 206331538 U CN206331538 U CN 206331538U
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Abstract
A kind of handheld POS terminal and its USB switching circuits, the USB switching circuits are arranged between a USB interface and a charging circuit；The USB switching circuits are made up of power switch chip and metal-oxide-semiconductor and its peripheral circuit；Wherein, the power switch chip and the metal-oxide-semiconductor are controlled by same control signal, when the control signal is low level, metal-oxide-semiconductor conducting so that the charging circuit is connected with the USB interface, and the USB interface is used as charging inlet；When the control signal is high level, metal-oxide-semiconductor cut-off, internal direct current supply is supplied to the USB interface via the power switch chip, and the USB interface is as communication interface and in main equipment pattern.The utility model can realize the multiplexing of communication and the charging of USB interface well.
Description
Technical field
The utility model is related to handheld POS terminal, more particularly, to the USB functions of handheld POS terminal.
Background technology
Handheld POS terminal generally includes casing and the functional circuit part containing microprocessor being installed in the casing,
The rechargeable battery powered for the functional circuit part and the charging inlet and communication interface for being installed in the cabinet sides.Its
In, conventional charging inlet is hole post shape.Conventional communication interface has RS232 ports and/or USB interface.With USB power source
More prevalent application, charging inlet is necessary to adopt USB interface.However, the space that port is installed on casing is limited, it is special to set
Individual USB interface waste very much solely to seem as charging inlet.It can be seen that, it is necessary to be improved existing circuit in fact, with
The existing USB interface as communication interface is made full use of to be charged.
Utility model content
Technical problem to be solved in the utility model is to overcome the shortcomings of present in above-mentioned prior art, and proposes one
The USB switching circuits of handheld POS terminal are planted, the multiplexing of communication and the charging of USB interface can be realized well.
The utility model proposes a kind of USB switching circuits of handheld POS terminal for above-mentioned technical problem, is arranged on one
Between USB interface and a charging circuit；The USB switching circuits are made up of power switch chip and metal-oxide-semiconductor and its peripheral circuit；Its
In, the power switch chip and the metal-oxide-semiconductor are controlled by same control signal, and when the control signal is low level, the metal-oxide-semiconductor is led
It is logical so that the charging circuit is connected with the USB interface, and the USB interface is used as charging inlet；It is high level in the control signal
When, metal-oxide-semiconductor cut-off, internal direct current supply is supplied to the USB interface via the power switch chip, the USB interface conduct
Communication interface is simultaneously in main equipment pattern.
In certain embodiments, the peripheral circuit includes：Two triodes for driving the metal-oxide-semiconductor；The two three poles
Pipe is controlled by the control signal, and the metal-oxide-semiconductor ends when the two triodes are both turned on, and the metal-oxide-semiconductor is equal in the two triodes
Turned on during cut-off.
In certain embodiments, the two triodes are the NPN type triode Q3 and PNP type triode Q29 cooperated；
Wherein, the control signal is added in NPN type triode Q3 base stage, NPN type triode Q3 grounded emitter, the NPN type
Triode Q3 colelctor electrode is connected with PNP type triode Q29 base stage, and PNP type triode Q29 emitter stage meets the USB
The VCC5V_USB ports of interface, PNP type triode Q29 colelctor electrode connects the grid of the metal-oxide-semiconductor.
The utility model also proposes a kind of handheld POS terminal, including microprocessor for above-mentioned technical problem, USB interface,
Charging circuit, rechargeable battery and DC-DC transfer circuit；And USB switching circuits as described above, the wherein control signal
There is provided by the microprocessor, the direct current supply of the inside is provided by the rechargeable battery via the DC-DC transfer circuit.
Compared with prior art, the USB switching circuits of handheld POS terminal of the present utility model, by dexterously using power supply
Switch chip and metal-oxide-semiconductor and its peripheral circuit are constituted, can be when the metal-oxide-semiconductor is turned on, and USB interface is as charging inlet, at this
When metal-oxide-semiconductor ends, internal direct current supply is supplied to USB interface via the power switch chip, and USB interface is used as communication interface
And in main equipment pattern, so as to the multiplexing of communication and the charging of realizing USB interface well.
Brief description of the drawings
Fig. 1 is the circuit block diagram of handheld POS terminal of the present utility model.
Fig. 2 is the electrical schematic diagram of the USB switching circuits of handheld POS terminal of the present utility model.
Embodiment
Below in conjunction with the accompanying drawing of this specification, further elaboration is given to preferred embodiment of the present utility model.
Referring to Fig. 1, Fig. 1 is the circuit block diagram of handheld POS terminal of the present utility model.The utility model proposes one kind is hand-held
POS terminal 10, it is generally comprised：Microprocessor 1, USB interface 2, rechargeable battery 3, DC-DC transfer circuit 4, charging circuit
5 and USB switching circuits 6.Wherein, the microprocessor 1 is powered by the rechargeable battery 3.Specifically, the rechargeable battery 3 is carried
The energy of confession carries out boosting processing via the DC-DC transfer circuit 4, and the direct current supply of inside is provided for the microprocessor 1
VCC5V.The USB interface 2 is communication and charging multiplexing.Wherein, when the USB interface 2 is as communication interface, USB switchings
After circuit 6 switches the direct current supply VCC5V of the inside via switch, the VCC5V_USB ports of the USB interface 2 are sent to, are outer
Portion's equipment（Such as USB flash disk）Power supply.When the USB interface 2 is as charging inlet, the USB switching circuits 6 are from the USB interface 2
The power taking of VCC5V_USB ports, after switch switching, is sent to the input port VCC5V_IN of charging circuit 5.
Specifically, it is controlled by the control signal VBUS_EN of the microprocessor 1, when the USB switching circuits 6 are in charging
During state, external power supply can be sent to charging electricity via the VCC5V_USB ports and the USB switching circuits 6 of the USB interface 2
The input VCC5V_IN on road 5, is charged by 5 pairs of rechargeable batteries 3 of the charging circuit.
It is controlled by the control signal VBUS_EN of the microprocessor 1, when the USB switching circuits 6 are in the logical of holotype state
During news state, the input VCC5V_IN of the charging circuit 5 disconnects with the VCC5V_USB ports of the USB interface 2.The direct current is supplied
Electric VCC5V switches via the inside of the USB switching circuits 6 to be switched, and is sent to the VCC5V_USB ports of the USB interface 2, Neng Gouwei
External USB equipment is powered.Meanwhile, the microprocessor 1 can be set by data wire USB+, USB- via the USB interface 2 with outside
Standby communication connection.
Referring to Fig. 2, Fig. 2 is the electrical schematic diagram of the USB switching circuits of handheld POS terminal of the present utility model.The USB switches
Circuit 6 is made up of power switch chip U7 and metal-oxide-semiconductor Q1 and its peripheral circuit.Wherein, the power switch chip U7 and the metal-oxide-semiconductor
Q1 is controlled by same control signal VBUS_EN, when control signal VBUS_EN is low level, metal-oxide-semiconductor Q1 conductings so that
The charging circuit 5 can be from the USB interface 2（That is the socket J1 in Fig. 2）The power taking of VCC5V_USB ports, the USB interface 2 makees
For charging inlet；When control signal VBUS_EN is high level, metal-oxide-semiconductor Q1 cut-offs, internal direct current supply VCC5V warps
The VCC5V_USB ports of the USB interface 2 are supplied to by power switch chip U7, the USB interface 2 is as communication interface and locates
In main equipment pattern.
The peripheral circuit mainly includes two triodes Q3, Q29 and some resistance.The two triodes Q3, Q29 are mutual
The NPN type triode Q3 and PNP type triode Q29 of cooperation.Wherein, the control signal VBUS_EN of the microprocessor 1 is via resistance
R141, R122 are added in NPN type triode Q3 base stage.NPN type triode Q3 grounded emitter.The NPN type triode
Q3 colelctor electrode is connected via resistance R176 with PNP type triode Q29 base stage.PNP type triode Q29 emitter stage connects
The VCC5V_USB ports of the USB interface 2.PNP type triode Q29 colelctor electrode connects the grid of the metal-oxide-semiconductor via resistance R120
Pole.NPN type triode Q3 colelctor electrode and the VCC5V_USB ports that the USB interface 2 is connect via resistance R137.
The operation principle of the USB switching circuits 6 is generally comprised：When power switch chip U7 4 pin/EN is high level,
1st pin OUT could export 5V voltages（From direct current supply VCC5V）.In the off-mode of handheld POS terminal 10,4 pin/EN
Low level, i.e. the 1st pin OUT output voltages are defaulted as 0V.When metal-oxide-semiconductor Q1 is turned on, external power source can be via the USB interface
2 VCC5V_USB ports are sent to the input VCC5V_IN of the charging circuit 5.
When the shutdown insertion external power source of handheld POS terminal 10 is charged by USB interface 2, metal-oxide-semiconductor Q1 acquiescence conductings, three
Pole pipe Q3 and Q29 are in cut-off state, and now USB interface 2 is only as charging inlet.
When handheld POS terminal 10 is started shooting, microprocessor 1 can be by signal VBUS_EN set low levels always.If at this moment
External power source is inserted, due to metal-oxide-semiconductor Q1 conductings, triode Q3, Q29 cut-off, now USB interface 2 is only as charging inlet.
Only USB interface 2 is being needed as HOST（Main equipment pattern）When, the ability set signal VBUS_EN of microprocessor 1 is
High level, for example：When inserting USB flash disk in USB interface 2, microprocessor 1 can be by signal VBUS_EN set high level, power switch
Chip U7 the 1st pin OUT output voltages are 5V, and this 5V powers for USB flash disk.When signal VBUS_EN is high level, triode Q3,
Q29 is turned on, metal-oxide-semiconductor Q1 cut-offs, now VCC5V_IN no-voltages, and charging circuit 5 does not work.
The USB switching circuits of handheld POS terminal of the present utility model, by dexterously using power switch chip U7 and MOS
Pipe Q1 and its peripheral circuit are constituted, can be when metal-oxide-semiconductor Q1 is turned on, and USB interface 2 is cut as charging inlet in metal-oxide-semiconductor Q1
When only, internal direct current supply VCC5V is supplied to USB interface 2 via power switch chip U7, and USB interface 2 connects as communication
Mouth is simultaneously in main equipment pattern, so as to the multiplexing of communication and the charging of realizing USB interface 2 well.
Also just say, by USB switching circuits 6, same USB interface 2 can be used to be charged to rechargeable battery 3, but work as USB
During external as the HOST output voltage of interface 2, and do not charged to rechargeable battery 3, so as to prevent as during USB-HOST pairs
During outer power supply, the appearance of the situation such as the supply current deficiency of handheld POS terminal 10, voltage pull-down.
The above is only preferred embodiment of the present utility model, is not intended to limit embodiment of the present utility model,
Those of ordinary skill in the art can very easily carry out corresponding accommodation according to central scope of the present utility model and spirit
Or modification, therefore protection domain of the present utility model should be defined by the protection domain required by claims.
Claims (4)
1. a kind of USB switching circuits of handheld POS terminal, are arranged between a USB interface and a charging circuit；Its feature exists
In the USB switching circuits are made up of power switch chip and metal-oxide-semiconductor and its peripheral circuit；Wherein, the power switch chip and should
Metal-oxide-semiconductor is controlled by same control signal, when the control signal is low level, metal-oxide-semiconductor conducting so that the charging circuit is with being somebody's turn to do
USB interface is connected, and the USB interface is used as charging inlet；When the control signal is high level, metal-oxide-semiconductor cut-off, internal is straight
Stream power supply is supplied to the USB interface via the power switch chip, and the USB interface is as communication interface and in main equipment mould
Formula.
2. the USB switching circuits according to the handheld POS terminal described in claim 1, it is characterised in that the peripheral circuit includes：
Two triodes for driving the metal-oxide-semiconductor；The two triodes are controlled by the control signal, and the metal-oxide-semiconductor is in the two three poles
End when pipe is both turned on, the metal-oxide-semiconductor is turned on when the two triodes are turned off.
3. the USB switching circuits according to the handheld POS terminal described in claim 2, it is characterised in that the two triodes are phase
The NPN type triode Q3 and PNP type triode Q29 mutually coordinated；Wherein, the control signal is added in NPN type triode Q3 base
Pole, NPN type triode Q3 grounded emitter, NPN type triode Q3 colelctor electrode and PNP type triode Q29 base
Extremely it is connected, PNP type triode Q29 emitter stage connects the VCC5V_USB ports of the USB interface, PNP type triode Q29's
Colelctor electrode connects the grid of the metal-oxide-semiconductor.
4. a kind of handheld POS terminal, including microprocessor, USB interface, charging circuit, rechargeable battery and DC-dc conversion electricity
Road；Characterized in that, also including the USB switching circuits as described in any one of claims 1 to 3, wherein the control signal is by this
Microprocessor is provided, and the direct current supply of the inside is provided by the rechargeable battery via the DC-DC transfer circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720009841.8U CN206331538U (en) | 2017-01-05 | 2017-01-05 | Handheld POS terminal and its USB switching circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720009841.8U CN206331538U (en) | 2017-01-05 | 2017-01-05 | Handheld POS terminal and its USB switching circuits |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206331538U true CN206331538U (en) | 2017-07-14 |
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ID=59294471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720009841.8U Active CN206331538U (en) | 2017-01-05 | 2017-01-05 | Handheld POS terminal and its USB switching circuits |
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| Country | Link |
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| CN (1) | CN206331538U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110417260A (en) * | 2019-07-23 | 2019-11-05 | 武汉洲际电讯科技股份有限公司 | A kind of switching power circuit of detectable electric current |
| CN111525648A (en) * | 2020-05-19 | 2020-08-11 | 上海摩勤智能技术有限公司 | Multifunctional base, electronic terminal and multi-joint switching method |
| WO2022000738A1 (en) * | 2020-07-02 | 2022-01-06 | 深圳市鹰硕教育服务有限公司 | Power driving circuit of intelligent pen |
-
2017
- 2017-01-05 CN CN201720009841.8U patent/CN206331538U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110417260A (en) * | 2019-07-23 | 2019-11-05 | 武汉洲际电讯科技股份有限公司 | A kind of switching power circuit of detectable electric current |
| CN111525648A (en) * | 2020-05-19 | 2020-08-11 | 上海摩勤智能技术有限公司 | Multifunctional base, electronic terminal and multi-joint switching method |
| WO2022000738A1 (en) * | 2020-07-02 | 2022-01-06 | 深圳市鹰硕教育服务有限公司 | Power driving circuit of intelligent pen |
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