CN105720431A - USB interface protection device in vehicle-mounted ECU - Google Patents
USB interface protection device in vehicle-mounted ECU Download PDFInfo
- Publication number
- CN105720431A CN105720431A CN201610167077.7A CN201610167077A CN105720431A CN 105720431 A CN105720431 A CN 105720431A CN 201610167077 A CN201610167077 A CN 201610167077A CN 105720431 A CN105720431 A CN 105720431A
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- CN
- China
- Prior art keywords
- nmos tube
- resistance
- voltage
- electric capacity
- counnter attack
- 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.)
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/665—Structural association with built-in electrical component with built-in electronic circuit
- H01R13/6675—Structural association with built-in electrical component with built-in electronic circuit with built-in power supply
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/66—Structural association with built-in electrical component
- H01R13/717—Structural association with built-in electrical component with built-in light source
- H01R13/7175—Light emitting diodes (LEDs)
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R2201/00—Connectors or connections adapted for particular applications
- H01R2201/26—Connectors or connections adapted for particular applications for vehicles
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a USB interface protection device in a vehicle-mounted ECU. A source of a first NMOS tube is taken as a power supply terminal; a drain of the first NMOS tube is connected with an anode of a first anti-reverse diode and a drain of a second NMOS tube; a gate of the first NMOS tube is connected with a cathode of a light-emitting diode, an output end of a voltage comparator and the gate of the second NMOS tube; the source of the second NMOS tube is connected with the cathode of a second anti-reverse diode and is taken as an output end; the cathode of the first anti-reverse diode is connected with one end of a first resistor and one end of a first capacitor; the other end of the first resistor is connected with an inverting input terminal of the voltage comparator and one end of a second resistor; a non-inverting input terminal of the voltage comparator is connected with an anode of the second anti-reverse diode, one end of a third resistor and one end of a second capacitor; the other end of the first capacitor, the other end of the second capacitor and the other end of the second resistor are grounded; the other end of the third resistor is used for receiving a reference voltage; and the anode of the light-emitting diode is used for receiving a power supply voltage.
Description
Technical field
The present invention relates to electronic circuit technology field, be specifically related to the USB interface protection device in a kind of vehicle-mounted ECU.
Background technology
In order to ensure traffic safety, the security performance of vehicle-mounted ECU requires significantly high, just to ensure that rate of breakdown is as far as possible low when design.As communication interface between the mobile peripheral hardware being most widely used at present and main frame, USB(UniversalSerialBus) have that cost is low, it is simple to use, support plug and play, be prone to the features such as extension, car entertainment and storage device obtain a wide range of applications.Owing to USB interface provides built-in power, it is possible to provide the electric current of more than 500mA, for the equipment that some power are bigger, such as portable hard drive etc., its instant drive current then can reach more than 1A.If in vehicle-mounted ECU with as usb bus this can the interface of direct out-put supply, interface can damage body when occurring power supply or shorted to earth, it is therefore necessary to provides a kind of in interface section and protects circuit, it is prevented that system failure, avoids causing security incident.
Summary of the invention
The problem being vehicle-mounted USB power source interface and causing body to damage power supply or shorted to earth to be solved by this invention.
The present invention is achieved through the following technical solutions:
USB interface protection device in a kind of vehicle-mounted ECU, including the first NMOS tube, the second NMOS tube, the first counnter attack diode, the second counnter attack diode, light emitting diode, the first electric capacity, the second electric capacity, the first resistance, the second resistance, the 3rd resistance and voltage comparator；The source electrode of described first NMOS tube is as power end, the drain electrode of described first NMOS tube connects the anode of described first counnter attack diode and the drain electrode of described second NMOS tube, the grid of described first NMOS tube connects the negative electrode of described light emitting diode, the outfan of described voltage comparator and the grid of described second NMOS tube, the source electrode of described second NMOS tube connects the negative electrode of described second counnter attack diode and as outfan, the negative electrode of described first counnter attack diode connects one end of described first resistance and one end of described first electric capacity, the other end of described first resistance connects the inverting input of described voltage comparator and one end of described second resistance, the in-phase input end of described voltage comparator connects the anode of described second counnter attack diode, one end of described 3rd resistance and one end of described second electric capacity, the other end of described first electric capacity, the other end of described second electric capacity and the other end ground connection of described second resistance, the other end of described 3rd resistance is used for receiving reference voltage, the anode of described light emitting diode is used for receiving supply voltage.
Optionally, described reference voltage is not higher than 3.3V.
The present invention compared with prior art, has such advantages as and beneficial effect:
USB interface protection device in vehicle-mounted ECU provided by the invention; can automatically detect whether USB outfan there occurs 12V or shorted to earth; only constitute the adjustable window comparator of threshold value with a comparator; achieve the effective protection to USB power supply circuits, it is prevented that when USB interface occurs 12V or shorted to earth, damage body.Further, by arranging light emitting diode, the described lumination of light emitting diode when USB interface occurs 12V or shorted to earth, it is simple to user judges short trouble.
Accompanying drawing explanation
Accompanying drawing described herein is used for providing being further appreciated by the embodiment of the present invention, constitutes the part of the application, is not intended that the restriction to the embodiment of the present invention.In the accompanying drawings:
Fig. 1 is the circuit diagram of the USB interface protection device in the vehicle-mounted ECU of the embodiment of the present invention.
Detailed description of the invention
For making the object, technical solutions and advantages of the present invention clearly understand, below in conjunction with embodiment and accompanying drawing, the present invention is described in further detail, and exemplary embodiment and the explanation thereof of the present invention are only used for explaining the present invention, not as a limitation of the invention.
Embodiment
Fig. 1 is the circuit diagram of the USB interface protection device in the vehicle-mounted ECU of the embodiment of the present invention, and the USB interface protection device in described vehicle-mounted ECU includes the first NMOS tube MN1, the second NMOS tube MN2, the first counnter attack diode D1, the second counnter attack diode D2, light emitting diode D3, the first electric capacity C1, the second electric capacity C2, the first resistance R1, the second resistance R2, the 3rd resistance R3 and voltage comparator A1.
Specifically, the source electrode of described first NMOS tube MN1, as power end VCC1, the built-in power voltage that voltage is USB interface on described power end VCC1, is generally 5V.The drain electrode of described first NMOS tube MN1 connects the anode of described first counnter attack diode D1 and the drain electrode of described second NMOS tube MN2, the grid of described first NMOS tube MN1 connects the negative electrode of described light emitting diode D3, the outfan of described voltage comparator A1 and the grid of described second NMOS tube MN2, the source electrode of described second NMOS tube MN2 connects the negative electrode of described second counnter attack diode D2 and as outfan VCC2, the negative electrode of described first counnter attack diode D1 connects one end of described first resistance R1 and one end of described first electric capacity C1, the other end of described first resistance R1 connects the inverting input of described voltage comparator A1 and one end of described second resistance R2, the in-phase input end of described voltage comparator A1 connects the anode of described second counnter attack diode D2, one end of described 3rd resistance R3 and one end of described second electric capacity C2, the other end of described first electric capacity C1, the other end of described second electric capacity C2 and the other end ground connection of described second resistance R2, the other end VCC3 of described 3rd resistance R3 is used for receiving reference voltage, the anode VCC4 of described light emitting diode D3 is used for receiving supply voltage.For the USB device that some power consumptions are bigger, the moment of its connection can by the voltage pull-down of outfan VCC2, and during this, the voltage of outfan VCC2 will between 3.3V and 5V.If now the voltage of the in-phase input end of described voltage comparator A1 has the risk that misoperation occurs more than 3.3V, described voltage comparator A1.Therefore, generally described reference voltage is set to not higher than 3.3V.
The operation principle of device is protected to illustrate the USB interface in the vehicle-mounted ECU of the present embodiment below:
Assume the in-phase input end voltage of described voltage comparator A1 be U+, inverting input voltage be U-, output end voltage be Uo, the forward voltage drop of described first counnter attack diode D1 is UD1, the forward voltage drop of described second counnter attack diode D2 is UD2, the anode potential of described first counnter attack diode D1 is Umid, has: U-=(Umid-UD1) × R1 ÷ (R1+R2).In normal operating conditions, U-< U+, Uo are high level, and described light emitting diode D3 is not luminous, and described first NMOS tube MN1 and described second NMOS tube MN2 turns on.Discuss in two kinds of situation below as the size of magnitude of voltage on described outfan VCC2:
(1) if the voltage of described outfan VCC2 is more than 5V, due to the direction cut-off effect of described second counnter attack diode D2, have: U+=3.3V.Again because of described first NMOS tube MN1 and the described second NMOS tube MN2 fast recovery diode effect carried, the voltage of described outfan VCC2 is equal with Umid.As U-> U+, the output level of described voltage comparator A1 reverses, it may be assumed that
Umid > 3.3 × (R1+R2) ÷ R1+UD1.
If now the voltage of described outfan VCC2 is VBUSH, can obtain:
VBUSH=3.3 × (R1+R2) ÷ R1+UD1.
Namely when the voltage of described outfan VCC2 more than 3.3 × (R1+R2) ÷ R1+UD1 time, two NMOS tube will be turned off by described voltage comparator A1.
(2) if the voltage of described outfan VCC2 is less than 3.3V, have: the U+ voltage equal to described outfan VCC2 and UD2 sum, Umid is equal with the voltage of power end VCC1 (being generally 5V).As U-> U+, the output level of described voltage comparator A1 reverses, if now the voltage of described outfan VCC2 is VBUSL, has:
VBUSL=(5V-UD1) × R1 ÷ (R1+R2)-UD2.
Namely when two NMOS tube will be turned off by the voltage of described outfan VCC2 less than (5V-UD1) × R1 ÷ (R1+R2)-UD2, described voltage comparator A1.
As the above analysis, the protection of the USB interface in the vehicle-mounted ECU of the present embodiment device only constitutes the adjustable window comparator of threshold value with a voltage comparator, it is achieved that the effective protection to USB power supply circuits.When the voltage being connected on outfan VCC2 is more than VBUSH or less than VBUSL, the output of described voltage comparator A1 will become low level, turn off described first NMOS tube MN1 and described second NMOS tube MN2, power end VCC1 and outfan be kept apart.Further, by arranging described light emitting diode D3, during outfan short circuit, described light emitting diode D3 is luminous, reminds user's outfan to be short-circuited fault.Further, the input terminal voltage that described first electric capacity C1 and described second electric capacity C2 can maintain described voltage comparator A1 is instantaneous constant.
Above-described detailed description of the invention; the purpose of the present invention, technical scheme and beneficial effect have been further described; it is it should be understood that; the foregoing is only the specific embodiment of the present invention; the protection domain being not intended to limit the present invention; all within the spirit and principles in the present invention, any amendment of making, equivalent replacement, improvement etc., should be included within protection scope of the present invention.
Claims (2)
1. the protection of the USB interface in vehicle-mounted ECU device; it is characterized in that, including the first NMOS tube, the second NMOS tube, the first counnter attack diode, the second counnter attack diode, light emitting diode, the first electric capacity, the second electric capacity, the first resistance, the second resistance, the 3rd resistance and voltage comparator；
The source electrode of described first NMOS tube is as power end, the drain electrode of described first NMOS tube connects the anode of described first counnter attack diode and the drain electrode of described second NMOS tube, the grid of described first NMOS tube connects the negative electrode of described light emitting diode, the outfan of described voltage comparator and the grid of described second NMOS tube, the source electrode of described second NMOS tube connects the negative electrode of described second counnter attack diode and as outfan, the negative electrode of described first counnter attack diode connects one end of described first resistance and one end of described first electric capacity, the other end of described first resistance connects the inverting input of described voltage comparator and one end of described second resistance, the in-phase input end of described voltage comparator connects the anode of described second counnter attack diode, one end of described 3rd resistance and one end of described second electric capacity, the other end of described first electric capacity, the other end of described second electric capacity and the other end ground connection of described second resistance, the other end of described 3rd resistance is used for receiving reference voltage, the anode of described light emitting diode is used for receiving supply voltage.
2. the protection of the USB interface in vehicle-mounted ECU according to claim 1 device, it is characterised in that described reference voltage is not higher than 3.3V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610167077.7A CN105720431A (en) | 2016-03-23 | 2016-03-23 | USB interface protection device in vehicle-mounted ECU |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610167077.7A CN105720431A (en) | 2016-03-23 | 2016-03-23 | USB interface protection device in vehicle-mounted ECU |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105720431A true CN105720431A (en) | 2016-06-29 |
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ID=56157980
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610167077.7A Pending CN105720431A (en) | 2016-03-23 | 2016-03-23 | USB interface protection device in vehicle-mounted ECU |
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| Country | Link |
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| CN (1) | CN105720431A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204481472U (en) * | 2014-12-31 | 2015-07-15 | 深圳市麦思美科技有限公司 | Overvoltage crowbar |
| CN104882869A (en) * | 2015-06-11 | 2015-09-02 | 国网四川省电力公司南充供电公司 | Mobile device data interface protective circuit |
| CN204967232U (en) * | 2015-08-20 | 2016-01-13 | 天津网赢科技有限公司 | Computer USB mouth power supply protection circuit |
| CN205489434U (en) * | 2016-03-23 | 2016-08-17 | 成都锐奕信息技术有限公司 | On -vehicle USB power short -circuit protection circuit |
-
2016
- 2016-03-23 CN CN201610167077.7A patent/CN105720431A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN204481472U (en) * | 2014-12-31 | 2015-07-15 | 深圳市麦思美科技有限公司 | Overvoltage crowbar |
| CN104882869A (en) * | 2015-06-11 | 2015-09-02 | 国网四川省电力公司南充供电公司 | Mobile device data interface protective circuit |
| CN204967232U (en) * | 2015-08-20 | 2016-01-13 | 天津网赢科技有限公司 | Computer USB mouth power supply protection circuit |
| CN205489434U (en) * | 2016-03-23 | 2016-08-17 | 成都锐奕信息技术有限公司 | On -vehicle USB power short -circuit protection circuit |
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| PB01 | Publication | ||
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Application publication date: 20160629 |