CN201222724Y - Circuit for switching signal - Google Patents
Circuit for switching signal Download PDFInfo
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- CN201222724Y CN201222724Y CNU2008201506171U CN200820150617U CN201222724Y CN 201222724 Y CN201222724 Y CN 201222724Y CN U2008201506171 U CNU2008201506171 U CN U2008201506171U CN 200820150617 U CN200820150617 U CN 200820150617U CN 201222724 Y CN201222724 Y CN 201222724Y
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Abstract
The utility model relates to a signal switching circuit, which mainly comprises three parts of a mutual conversion circuit between a KlineTTL electrical level and a RS232 negative logic electrical level, a 12V adaptive circuit and a 24V adaptive circuit, and an anti-reversal protection circuit. Compared with the prior art, the utility model has the advantages that the circuit is applied to a 12V system and a 24V system and has the functions of anti-reversal connection and the like.
Description
Technical field
The utility model relates to level shifting circuit, is specifically related to a kind of change-over circuit that a kind of Transistor-Transistor Logic level with the Kline bus converts the negative logic level of RS232 to.
Background technology
At present, there is the identical change-over circuit of a variety of functions on the market, but all can not be applied to the main flow onboard diagnostic system fully, because the main flow vehicle power comprises 12V and two kinds of systems of 24V, these conversions or be applicable to the 12V system, be applicable to the 24V system, be difficult to be applicable to simultaneously two kinds of power-supply systems.Simultaneously, because the complexity of vehicle-mounted circuit, when circuit connected the terminals wrong line of ECU end, the entire circuit system was easy to burn, and causes the raising of user's waste of time and developer's cost.
The utility model content
The purpose of this utility model is exactly the signal switching circuit that a kind of 12V of being applicable to and 24V system are provided for the defective that overcomes above-mentioned prior art existence.
The purpose of this utility model can be achieved through the following technical solutions: a kind of signal switching circuit, it is characterized in that this circuit mainly is made up of mutual shifting circuit, 12V and 24V adaptive circuit between Kline Transistor-Transistor Logic level and the RS232 negative logic level, anti-reverse protective circuit three parts; Mutual shifting circuit between described Kline Transistor-Transistor Logic level and the RS232 negative logic level is made up of diode D2, resistance R 2, resistance R 3, diode D3, diode D4, NPN triode Q2, resistance R 10, resistance R 6, resistance R 7, resistance R 8, resistance R 9, PNP triode Q1 and resistance R 4; Described 12V and 24V adaptive circuit are made up of diode D2, resistance R 2, resistance R 3, NPN triode Q2, resistance R 10, resistance R 6, resistance R 7, resistance R 8, resistance R 9, PNP triode Q1 and resistance R 4; Described anti-reverse protective circuit is made up of diode D2, diode D3, diode D4.
The base stage of described PNP triode Q1 connects resistance R 6, the emitter of PNP triode Q1 connects parallel resistor R8 and resistance R 9, and between the base stage of PNP triode Q1 and emitter, be provided with parallel resistor R7 and diode D5, the collector electrode of PNP triode Q1 connects the Rx PIN2 pin of RS232, and by resistance R 4 ground connection.
Described anti-reverse protective circuit is made up of diode D2, diode D3, diode D4; the P end of diode D2 connects power supply Battery_Power; its N end connects parallel resistor R2 and resistance R 3; be connected to the P end of diode D3; the N end of diode D3 connects the P end of diode D4, and the N end of diode D4 connects the collector electrode of NPN triode Q2.
Compared with prior art, the utility model converts the Transistor-Transistor Logic level of Kline bus a kind of change-over circuit of the negative logic level of RS232 to, in order to realize based on the ECU (electronic control unit) of the Kline bus of ISO14230 diagnostic criteria and the communication between the PC RS232.Have the following advantages:
1. native system is applicable to 12V and 24V system.Now vehicle power mainly contains two kinds of 12V on the market with 24V, the adapter of a lot of manufacturer production or at the 12V system, or at the 24V system; And two kinds of power supplys of native system can be suitable for.
2. the anti-reverse function of native system band.The adapter of a lot of producers is easy to burn on the market, and adapter connects the controller end three connecting lines: power supply, signal and ground, use under the user because of carelessness the situation of these several connecting line wrongs, and very easily burn adapter; And the anti-reverse function of native system band, three any reversal connections of connecting line can not burnt adapter, can not influence the normal communication that connects under the correct situation yet.
Description of drawings
Fig. 1 is a schematic diagram of the present utility model.
Embodiment
The utility model is described in further detail below in conjunction with accompanying drawing.
Among Fig. 1 shown in the label:
R1:5K resistance, R2, R3:1K power resistor, R4:1K resistance, R5:1K resistance, R6:5K resistance, R7:3.3K resistance, R8, R9:510 Ω power resistor, R10:2K resistance, R11:5K resistance, R12:1K resistance, D1, D6, D8: light-emitting diode, D2, D5, D7: diode, D3, D4: diode, the Q1:PNP triode, Q2:NPN triode, Z1:20V voltage-stabiliser tube.
Embodiment 1
As shown in Figure 1, a kind of novel Kline RS 232 conversion is characterized in that this circuit mainly is made up of mutual shifting circuit, 12V and 24V adaptive circuit between KlineTTL level and the RS232 negative logic level, anti-reverse protective circuit three parts; Mutual shifting circuit between described Kline Transistor-Transistor Logic level and the RS232 negative logic level is made up of D2, R2, R3, D3, D4, Q2, R10, R6, R7, R8, R9, Q1 and R4; Described 12V and 24V adaptive circuit are made up of D2, R2, R3, Q2, R10, R6, R7, R8, R9, Q1 and R4, are the resistors match realizations by whole system; Described anti-reverse protective circuit is made up of D2, D3, D4.
Mutual shifting circuit between described Kline Transistor-Transistor Logic level and the RS232 negative logic level, when the TxPIN3 of RS232 pin output high level, Q2 enters the saturation conduction state, at this moment K-line pin output low level; When the Tx of RS232 PIN3 pin output low level, Q2 enters cut-off state, and this moment, the K-line pin was by moving high level on R2, the R3.When K-line pin output high level, Q1 enters cut-off state, and the RxPIN2 of RS232 pulled down to low level; When K-line pin output low level, Q1 enters the saturation conduction state, the RxPIN2 of RS232 by on move high level to.
Described 12V and 24V adaptive circuit, because the reasonability of resistors match makes that Q1, Q2 can both enter saturated or cut-off state no matter system works still works in 24V in 12V, system all can operate as normal.By the minimum positive voltage 3V of standard RS232, the triode gain is 80 calculating: if system works is when the 12V state, when RS232 sends high level signal, make triode Q2 saturated, the base current that needs is (12-0.7-0.7-0.3)/(80*0.5)=0.2575mA, the electric current that the Tx pin can provide is (3-0.7)/2=1.15mA, so Q2 can saturation conduction, K-line drags down by D4 and is low level; When RS232 sent low level signal, Q2 ended, and K-line is pulled down to high level by D2, R2, R3, D3.When K-line sent high level signal, Q1 ended, and Rx PIN2 drags down by R4 and is low level; When K-line sends low level signal, make triode Q1 saturated, the base current that needs is (12-0.3)/(80*1.255)=0.117mA, and this moment, the Q1 emitter voltage was 9.6V, the base current of Q1 is (9.6-0.7)/5=1.78mA, so Q1 can saturation conduction.If system works is when the 24V state, when RS232 sends high level signal, make triode Q2 saturated, the base current that needs is (24-0.7-0.7-0.3)/(80*0.5)=0.5575mA, the electric current that the Tx pin can provide is (3-0.7)/2=1.15mA, so Q2 can saturation conduction, K-line drags down by D4 and is low level; When RS232 sent low level signal, Q2 ended, and K-line is pulled down to high level by D2, R2, R3, D3.When K-line sent high level signal, Q1 ended, and Rx PIN2 drags down by R4 and is low level; When K-line sends low level signal, make triode Q1 saturated, the base current that needs is (24-0.3)/(80*1.255)=0.236mA, and this moment, the Q1 emitter voltage was 19.4V, the base current of Q1 is (19.4-0.7)/5=3.74mA, so Q1 can saturation conduction.
Described anti-reverse protective circuit; if Battery_Power connects right; K-line is connected into power cathode; Battery_GND is connected into signal; can form the loop between R2, R3, the D3, though there is this moment big electric current to flow through in the loop, because R2, R3 are high-power resistances; the electric current that D3 flows through can not surpass its rated current, can not damage components and parts.If Battery_Power is connected into signal, if K-line is connected into power supply, Battery_GND still connects power cathode, and when Tx PIN3 output high level, Q2 can have very big electric current to pass through moment, but owing to the time is very short, so also can not damage components and parts; If K-line is connected into ground, Battery_GND connects power supply, because the acting in opposition of D3, D4 does not have the loop to form in the system.If Battery_Power is connected into ground, if K-line is connected into power supply, Battery_GND is connected into signal, and system does not have the loop to form; If K-line is connected into letter, Battery_GND is connected into power supply, and system does not have the loop to form yet.
The base stage of NPN triode Q3 connects 5K resistance R 11, its grounded emitter, and its collector electrode is connected Battery_Power1 by 1K resistance R 12 with LED light-emitting diode D8, and NPN triode Q3 plays indicative function when communication.
Claims (3)
1. a signal switching circuit is characterized in that, this circuit mainly is made up of mutual shifting circuit, 12V and 24V adaptive circuit between Kline Transistor-Transistor Logic level and the RS232 negative logic level, anti-reverse protective circuit three parts; Mutual shifting circuit between described Kline Transistor-Transistor Logic level and the RS232 negative logic level is made up of diode (D2), resistance (R2), resistance (R3), diode (D3), diode (D4), NPN triode (Q2), resistance (R10), resistance (R6), resistance (R7), resistance (R8), resistance (R9), PNP triode (Q1) and resistance (R4); Described 12V and 24V adaptive circuit are made up of diode (D2), resistance (R2), resistance (R3), NPN triode (Q2), resistance (R10), resistance (R6), resistance (R7), resistance (R8), resistance (R9), PNP triode (Q1) and resistance (R4); Described anti-reverse protective circuit is made up of diode (D2), diode (D3), diode (D4).
2. a kind of signal switching circuit according to claim 1, it is characterized in that, the base stage of described PNP triode (Q1) connects resistance (R6), the emitter of PNP triode (Q1) connects parallel resistor (R8) and resistance (R9), and between the base stage of PNP triode (Q1) and emitter, be provided with parallel resistor (R7) and diode (D5), the collector electrode of PNP triode (Q1) connects the Rx PIN2 pin of RS232, and by resistance (R4) ground connection.
3. a kind of signal switching circuit according to claim 1; it is characterized in that; described anti-reverse protective circuit is made up of diode (D2), diode (D3), diode (D4); the P end of diode (D2) connects power supply Battery_Power; its N end connects parallel resistor (R2) and resistance (R3); be connected to the P end of diode (D3), the N end of diode (D3) connects the P end of diode (D4), and the N end of diode (D4) connects the collector electrode of NPN triode (Q2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201506171U CN201222724Y (en) | 2008-07-08 | 2008-07-08 | Circuit for switching signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201506171U CN201222724Y (en) | 2008-07-08 | 2008-07-08 | Circuit for switching signal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201222724Y true CN201222724Y (en) | 2009-04-15 |
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ID=40576226
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201506171U Expired - Fee Related CN201222724Y (en) | 2008-07-08 | 2008-07-08 | Circuit for switching signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201222724Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101626230B (en) * | 2008-07-08 | 2012-08-08 | 上海海能汽车电子有限公司 | Kline-RS232 circuit with function of preventing reverse connection |
| CN107482605A (en) * | 2017-09-30 | 2017-12-15 | 广西玉柴机器股份有限公司 | A kind of anti-over-pressed K line communication devices |
-
2008
- 2008-07-08 CN CNU2008201506171U patent/CN201222724Y/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101626230B (en) * | 2008-07-08 | 2012-08-08 | 上海海能汽车电子有限公司 | Kline-RS232 circuit with function of preventing reverse connection |
| CN107482605A (en) * | 2017-09-30 | 2017-12-15 | 广西玉柴机器股份有限公司 | A kind of anti-over-pressed K line communication devices |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090415 Termination date: 20110708 |