WO2021135814A1 - 一种隔离电路、汽车诊断设备及汽车诊断系统 - Google Patents

一种隔离电路、汽车诊断设备及汽车诊断系统 Download PDF

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Publication number
WO2021135814A1
WO2021135814A1 PCT/CN2020/133795 CN2020133795W WO2021135814A1 WO 2021135814 A1 WO2021135814 A1 WO 2021135814A1 CN 2020133795 W CN2020133795 W CN 2020133795W WO 2021135814 A1 WO2021135814 A1 WO 2021135814A1
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WIPO (PCT)
Prior art keywords
circuit
power supply
switch
automobile
signal
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PCT/CN2020/133795
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English (en)
French (fr)
Inventor
陈华明
庞海波
陆宏华
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深圳市道通科技股份有限公司
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Application filed by 深圳市道通科技股份有限公司 filed Critical 深圳市道通科技股份有限公司
Publication of WO2021135814A1 publication Critical patent/WO2021135814A1/zh
Priority to US17/807,987 priority Critical patent/US20220314908A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K19/00—Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
    • H03K19/0175—Coupling arrangements; Interface arrangements
    • H03K19/017545—Coupling arrangements; Impedance matching circuits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • B60R16/023—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for transmission of signals between vehicle parts or subsystems
    • B60R16/0231—Circuits relating to the driving or the functioning of the vehicle
    • B60R16/0232—Circuits relating to the driving or the functioning of the vehicle for measuring vehicle parameters and indicating critical, abnormal or dangerous conditions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/30—Structural combination of electric measuring instruments with basic electronic circuits, e.g. with amplifier
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/16—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using capacitive devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/005—Testing of electric installations on transport means
    • G01R31/006—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks
    • G01R31/007—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks using microprocessors or computers

Definitions

  • This application relates to the field of automobile diagnosis, in particular to an isolation circuit, automobile diagnosis equipment and automobile diagnosis system.
  • the car diagnostic equipment is used to connect with the OBD connector of the car to be diagnosed, to read the fault code of the car to be diagnosed, and to locate the location and cause of the failure.
  • the design size of the non-standard OBD connector differs from that of the standard OBD connector, which may cause the car diagnostic equipment to be connected to the OBD connector Poor grounding, that is, the positive pole of the car power supply is connected to the car diagnostic equipment before the negative pole of the car power supply, so that the instrument panel of the car to be diagnosed will turn on the fault light, which will easily interfere with the judgment of the car maintenance personnel.
  • the embodiments of the present invention aim to provide an isolation circuit, an automobile diagnostic equipment, and an automobile diagnostic system, which can avoid poor grounding and improve the reliability of the automobile diagnostic equipment.
  • the embodiments of the present invention provide the following technical solutions:
  • an embodiment of the present invention provides an isolation circuit, which is applied to automobile diagnostic equipment, and the isolation circuit includes:
  • the first switch circuit is electrically connected between the OBD connector of the vehicle to be diagnosed and the diagnostic device of the vehicle diagnostic equipment, and the OBD connector is also electrically connected to the vehicle power supply of the vehicle to be diagnosed;
  • the switch control circuit is respectively electrically connected to the OBD connector and the first switch circuit, and is used to detect that the OBD connector outputs a positive signal of the power supply, and it is not detected that the OBD connector outputs a negative signal of the power supply ,
  • the switch control circuit does not work, so that the first switch circuit works in the off state, so as to keep the diagnostic device not powered on; when the OBD connector is detected to output the positive signal of the power supply, and all the signals are detected
  • the OBD connector outputs a negative signal of the power supply, it outputs a control signal to make the first switch circuit work in a conducting state, so that the vehicle power supply supplies power to the diagnostic device.
  • the car power supply includes a car power supply positive electrode and a car power supply negative electrode
  • the car power supply positive electrode is used to output the power supply positive signal
  • the car power supply positive electrode is used to output the power supply negative signal
  • the switch control circuit include:
  • a bias circuit electrically connected to the positive pole of the automobile power supply, and used for converting the power supply voltage output by the positive pole of the automobile power supply into a bias voltage
  • the second switch circuit is electrically connected to the positive pole of the vehicle power supply
  • a step-down chopper circuit electrically connected to the second switch circuit, the negative pole of the automobile power supply, and the first switch circuit;
  • the controller is electrically connected to the positive pole of the automobile power supply, the negative pole of the automobile power supply, the bias circuit, the second switch circuit, and the step-down chopper circuit, and is used for detecting the OBD connector
  • the controller does not work; when the OBD connector is detected to output the power positive signal, and the OBD connector is detected to output power
  • the current detection signal flowing through the second switch circuit is detected, and a pulse width modulation signal is output according to the bias voltage and the current detection signal to control the working state of the second switch circuit.
  • the step-down chopper circuit is made to output the control signal.
  • the bias circuit includes a first resistor and a first capacitor
  • One end of the first resistor is connected to the positive pole of the automobile power supply, one end of the first capacitor, and the second switch circuit, and the other end of the first resistor is connected to the other end of the first capacitor and the second switch circuit. Controller connection.
  • the second switch circuit includes a PMOS tube, the gate of the PMOS tube is connected to the controller, the source of the PMOS tube is connected to the positive electrode of the vehicle power supply, and the drain of the PMOS tube is It is connected with the controller and the step-down chopper circuit.
  • the step-down chopper circuit includes:
  • the freewheeling circuit is electrically connected to the second switch circuit and the negative pole of the automobile power supply, and is used for when the second switch circuit is working in the on state, the freewheeling circuit is working in the off state, and when the When the second switch circuit works in the off state, the freewheeling circuit works in the on state;
  • the charging and discharging circuit is electrically connected to the second switch circuit, the freewheeling circuit, the negative pole of the automobile power supply, and the first switch circuit, and is used to output a positive power signal when the OBD connector is detected, and When detecting that the OBD connector outputs the negative signal of the power supply, when the freewheeling circuit is in the off state, charging is performed, and when the freewheeling circuit is in the on state, discharging is performed to output the control Signal and send the control signal to the first switch circuit.
  • the freewheeling circuit includes a diode, the anode of the diode is connected to the negative electrode of the automobile power supply, and the cathode of the diode is connected to the drain of the PMOS tube and the charging and discharging circuit.
  • the charging and discharging circuit includes an inductor and a second capacitor
  • One end of the inductor is connected to the cathode of the diode and the drain of the PMOS tube, and the other end of the inductor is connected to one end of the second capacitor and the first switch circuit; The other end is connected to the negative pole of the automobile power supply.
  • the switch control circuit further includes a voltage sampling circuit, which is respectively electrically connected to the negative pole of the automobile power supply, the step-down chopper circuit, the first switch circuit, and the controller for sampling the A control signal, so that the controller feedbacks and adjusts the control signal.
  • a voltage sampling circuit which is respectively electrically connected to the negative pole of the automobile power supply, the step-down chopper circuit, the first switch circuit, and the controller for sampling the A control signal, so that the controller feedbacks and adjusts the control signal.
  • the second resistor and the third resistor of the voltage sampling circuit are optionally, the second resistor and the third resistor of the voltage sampling circuit.
  • One end of the second resistor is connected to the step-down chopper circuit and the first switch circuit, and the other end of the second resistor is connected to one end of the third resistor and the controller; the first The other end of the three resistors is connected to the negative pole of the automobile power supply.
  • the switch control circuit further includes an input filter circuit, which is electrically connected between the positive pole of the automobile power supply and the negative pole of the automobile power supply, and is used for filtering the power supply voltage.
  • the input filter circuit includes a third capacitor, one end of the third capacitor is connected to the positive pole of the vehicle power supply, and the other end of the third capacitor is connected to the negative pole of the vehicle power supply.
  • the isolation circuit further includes a slow-start circuit, which is electrically connected to the first switch circuit and the diagnostic device, respectively, and is used for correcting when the working state of the first switch circuit is switched to the conducting state.
  • the power supply voltage output by the automobile power supply is processed for delay.
  • the first switch circuit includes:
  • the first switch is electrically connected between the positive pole of the vehicle power supply and the diagnostic device, and is also electrically connected to the switch control circuit, for working in a conducting state according to the control signal;
  • the second switch is electrically connected between the negative pole of the automobile power supply and the diagnostic device, and is also electrically connected to the switch control circuit, and is used for working in a conducting state according to the control signal.
  • an automobile diagnostic equipment including:
  • the diagnostic unit is electrically connected to the isolation circuit and is also in communication connection with the vehicle to be diagnosed, and is used to work according to the power supply voltage provided by the vehicle power supply of the vehicle to be diagnosed when the isolation circuit is working in the conducting state, And, obtain the diagnosis data of the vehicle to be diagnosed.
  • an automobile diagnosis system including:
  • the upper computer is in communication connection with the car diagnostic equipment, and is used to display the diagnostic data sent by the car diagnostic equipment.
  • the embodiments of the present invention provide an isolation circuit, a car diagnostic equipment and a car diagnostic system, which are electrically connected to the OBD connector of the car to be diagnosed and the car through a first switch circuit.
  • the OBD connector is also electrically connected to the vehicle power supply of the vehicle to be diagnosed
  • the switch control circuit is electrically connected to the OBD connector and the first switch circuit respectively, and is used to output the positive signal of the power supply when the OBD connector is detected.
  • the switch control circuit does not work, so that the first switch circuit works in the off state to keep the diagnostic device not powered on, and the OBD connector outputs the power positive signal when the OBD connector is detected , And when the OBD connector is detected to output the negative signal of the power supply, it outputs a control signal to make the first switch circuit work in a conductive state, so that the car power supply supplies power to the diagnostic device. Therefore, the embodiment of the present invention can avoid poor grounding and improve Reliability of automotive diagnostic equipment.
  • FIG. 1 is a schematic structural diagram of an automobile diagnosis system provided by an embodiment of the present invention
  • FIG. 2 is a schematic structural diagram of an automobile diagnostic equipment provided by an embodiment of the present invention.
  • FIG. 3 is a schematic structural diagram of an isolation circuit provided by an embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of an isolation circuit provided by another embodiment of the present invention.
  • FIG. 5 is a schematic structural diagram of a switch control circuit provided by an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of circuit connection of a switch control circuit provided by an embodiment of the present invention.
  • FIG. 1 is a schematic structural diagram of an automobile diagnosis system provided by an embodiment of the present invention.
  • the automobile diagnosis system 500 includes automobile diagnosis equipment 300 and an upper computer 400 as described in the following device embodiments.
  • the upper computer 400 is in communication connection with the automobile diagnosis equipment 300 for displaying the Diagnostic data sent by the car diagnostic equipment 300.
  • the automobile diagnosis system provided by the embodiment of the present invention avoids the phenomenon of poor grounding through automobile diagnosis equipment, thereby improving the reliability of diagnosis.
  • FIG. 2 is a schematic structural diagram of an automobile diagnostic equipment provided by an embodiment of the present invention.
  • the automobile diagnostic equipment 300 includes an isolation circuit 100 and a diagnostic device 200 as described in the following circuit embodiments.
  • the diagnostic device 200 is electrically connected to the isolation circuit 100, and is also communicatively connected to the vehicle 11 to be diagnosed, and is used to provide the vehicle power supply 112 of the vehicle 11 to be diagnosed when the isolation circuit 100 is in a conducting state.
  • the power supply voltage is higher than the power supply voltage, and the diagnosis data of the vehicle 11 to be diagnosed is obtained.
  • the vehicle to be diagnosed 11 includes an OBD connector 111, a vehicle power supply 112, and an on-board automatic diagnosis system (not shown).
  • the car power supply 112 includes a car power supply positive electrode and a car power supply negative electrode.
  • the car power supply positive electrode is used to output the power supply positive signal
  • the car power supply positive electrode is used to output the power supply negative signal.
  • the OBD connector 111 is electrically connected to the positive pole of the vehicle power supply and the negative pole of the vehicle power supply, respectively.
  • the OBD connector 111 is electrically connected to the isolation circuit 100 and is communicatively connected to the diagnostic device 200.
  • the isolation circuit 100 is used to enable the automobile power supply 112 to provide power to the diagnostic device 200 through the isolation circuit 100, and when the diagnostic device 200 After power-on, the diagnostic data of the vehicle 11 to be diagnosed is obtained through the OBD connector 111; if the OBD connector 111 and the isolation circuit 100 are poorly grounded, the isolation circuit 100 is used to cut off the power supply of the vehicle 112 and the power supply circuit of the diagnostic device 200 to keep the diagnostic device 200 off.
  • the automobile power supply 112 is used to provide a low-voltage DC power supply (usually 12V for gasoline vehicles and 24V for diesel vehicles) for all electrical equipment in the automobile 11 to be diagnosed, so that all parts of the automobile 11 to be diagnosed can work normally.
  • a low-voltage DC power supply usually 12V for gasoline vehicles and 24V for diesel vehicles
  • the car power supply 112 is also used to provide power for the car diagnostic equipment 300.
  • the on-vehicle automatic diagnosis system is also electrically connected to the OBD connector 111 (not shown) for monitoring the vehicle 11 to be diagnosed, generating diagnostic data, and when the diagnostic device 200 is powered on, it passes through the The OBD connector 111 sends the diagnostic data to the diagnostic device 200.
  • the power supply positive signal and the power supply negative signal reach the isolation circuit 100 through the OBD connector 111, and the isolation circuit 100 is used to detect the power supply positive signal and the power supply negative signal.
  • the OBD connector 111 outputs a positive power signal, and the OBD connector 111 does not detect a negative power signal, keep the diagnostic device 200 off; when it detects that the OBD connector 111 outputs a positive power
  • the automobile power supply 112 is enabled to supply power to the diagnostic device 200.
  • the automotive diagnostic equipment provided by the embodiment of the present invention can avoid poor grounding of the automotive diagnostic equipment through an isolation circuit, thereby improving the reliability of the automotive diagnostic equipment.
  • FIG. 3 is a schematic structural diagram of an isolation circuit provided by an embodiment of the present invention.
  • the isolation circuit 100 is applied to an automobile diagnostic equipment 300 and includes a first switch circuit 10 and a switch control circuit 20.
  • the first switch circuit 10 is electrically connected between the OBD connector 111 of the vehicle to be diagnosed 11 and the diagnostic device 200 of the vehicle diagnostic equipment 300, and the OBD connector 111 is also connected to the vehicle power supply of the vehicle to be diagnosed 11 112 electrical connection.
  • the first switch circuit 10 includes a first switch 101 and a second switch 102.
  • the first switch 101 is electrically connected between the positive pole of the vehicle power supply and the diagnostic device 200, and is also electrically connected to the switch control circuit 20, for operating in a conducting state according to the control signal.
  • the second switch 102 is electrically connected between the negative pole of the vehicle power supply and the diagnostic device 200, and is also electrically connected to the switch control circuit 20, for operating in a conducting state according to the control signal.
  • the first switch 101 and the second switch 102 are normally closed switches. It works in a conducting state according to the control signal, and when the controller 204 is not working, it returns to a normally closed state.
  • the first switch 101 and the second switch 102 when the first switch 101 and the second switch 102 are both working in the on state, the first switch 101 and the second switch 102 pass through the OBD connector 111 of the vehicle 11 to be diagnosed.
  • the first switch 101 and the second switch 102 include a metal-oxide semiconductor field effect transistor, a bipolar transistor, a relay, a switch circuit composed of other transistors, and the like.
  • the controller 204 when the controller 204 is not working, the output pins of the controller 204 corresponding to the first switch 101 and the second switch 102 are set low, and the switch control circuit 20 does not output a control signal , So that the first switch 101 and the second switch 102 work in the off state; when the controller 204 works, the controller 204 and the first switch 101 and the second switch 102 The corresponding output pin outputs a pulse width modulation signal, and the switch control circuit 20 outputs a control signal to make the first switch 101 and the second switch 102 work in a conducting state.
  • the switch control circuit 20 is electrically connected to the OBD connector 111 and the first switch circuit 10, respectively, for outputting a positive power signal when the OBD connector 111 is detected, and the OBD connector is not detected 111 when the negative signal of the power supply is output, the switch control circuit 20 does not work, so that the first switch circuit 10 works in the off state to keep the diagnostic device 200 off; when the OBD connector is detected 111 outputs the positive signal of the power supply, and when it is detected that the OBD connector 111 outputs the negative signal of the power supply, it outputs a control signal to make the first switch circuit 10 work in the conducting state, so that the automobile power supply 112 is the The diagnostic device 200 supplies power.
  • the switch control circuit 20 detects that the OBD connector 111 outputs the positive signal of the power supply, and fails to detect the negative signal of the OBD connector 111 outputting the power supply, including the following situations: the positive pole of the automobile power supply is connected before the negative pole of the automobile power supply.
  • the switch control circuit 20 detects that the OBD connector outputs a positive signal of the power supply, and detects that the OBD connector outputs a negative signal of the power supply, including the following two situations: 1.
  • the positive pole of the automobile power supply and the negative pole of the automobile power supply are connected at the same time.
  • the isolation circuit 100 2. After the positive pole of the vehicle power supply is connected to the isolation circuit 100 at the negative pole of the vehicle power supply.
  • the switch control circuit 20 detects that the OBD connector 111 outputs a positive power signal, and does not detect that the OBD connector 111 outputs a negative power signal, at this time, the positive pole of the automobile power supply is the switch control circuit 20. Provides input voltage. Since the switch control circuit 20 is not grounded, the switch control circuit 20 does not work, so that the first switch circuit 10 works in an off state to cut off the automobile power supply 112 and the diagnostic device 200 The power supply loop keeps the diagnostic device 200 unpowered.
  • the switch control circuit 20 includes a bias circuit 201, a second switch circuit 202, a step-down chopper circuit 203, a controller 204, a voltage sampling circuit 205, and an input filter circuit 206.
  • the bias circuit 201 is electrically connected to the positive pole of the automobile power supply for converting the power supply voltage output by the positive pole of the automobile power supply into a bias voltage.
  • the bias circuit 201 includes a first resistor R1 and a first capacitor C1.
  • one end of the first resistor R1 is connected to the positive pole of the vehicle power supply, one end of the first capacitor C1, and the second switch circuit 202, and the other end of the first resistor R1 is connected to the first capacitor.
  • the other end of C1 is connected to the controller 204.
  • the controller 204 includes a constant current source for providing a constant current i.
  • the power supply voltage starts slowly under the action of the volume of the first resistor R1 and the first capacitor C1 to avoid the influence of spike voltage on the controller 204 and protect the controller 204 from being burnt out.
  • the second switch circuit 202 is electrically connected to the positive pole of the automobile power supply.
  • the second switch circuit 202 includes a PMOS tube Q1, the gate of the PMOS tube Q1 is connected to the controller 204, the source of the PMOS tube Q1 is connected to the positive electrode of the vehicle power supply, and the PMOS tube The drain of Q1 is connected to the controller 204 and the step-down chopper circuit 203.
  • the second switch circuit 202 further includes components such as resistors and/or capacitors, which are used to limit the gate-source voltage of the PMOS transistor Q1 and prevent the PMOS transistor Q1 from being affected by the excessively high gate-source voltage. breakdown.
  • the step-down chopper circuit 203 is electrically connected to the second switch circuit 202, the negative pole of the automobile power supply, and the first switch circuit 10, respectively.
  • the step-down chopper circuit 203 includes a freewheeling circuit 2031 and a charging and discharging circuit 2032.
  • the freewheeling circuit 2031 is electrically connected to the second switch circuit 202 and the negative electrode of the automobile power supply, and is used for turning off the freewheeling circuit 2031 when the second switch circuit 202 is working in the on state.
  • the freewheeling circuit 2031 is in the on state.
  • the freewheeling circuit 2031 includes a diode D1, the anode of the diode D1 is connected to the negative electrode of the automobile power supply, the cathode of the diode D1 is connected to the drain of the PMOS transistor Q1 and the charge and discharge Circuit 2032 is connected.
  • the charging and discharging circuit 2032 is electrically connected to the second switch circuit 202, the freewheeling circuit 2031, the negative pole of the automobile power supply, and the first switch circuit 10, respectively, for detecting the OBD connector 111
  • the OBD connector 111 is detected to output the negative signal of the power supply
  • the freewheeling circuit 2031 is working in the off state
  • charging is performed
  • the freewheeling circuit 2031 is working in the on state
  • the discharge is performed to output the control signal, and send the control signal to the first switch circuit 10.
  • the charging and discharging circuit 2032 includes an inductor L1 and a second capacitor C2.
  • one end of the inductor L1 is connected to the cathode of the diode D1 and the drain of the PMOS transistor Q1, and the other end of the inductor L1 is connected to one end of the second capacitor C2 and the first switch circuit 10 Connection; the other end of the second capacitor C2 is connected to the negative pole of the vehicle power supply.
  • the pulse width modulation signal is used to modulate the duty cycle of the PMOS transistor Q1.
  • the diode D1 is reverse-biased, and the power supply voltage is charged through the inductor L1 to charge the first switch circuit 10.
  • the current flowing through the inductor L1 If iL increases, the energy storage of the inductor L1 increases.
  • the controller 204 outputs the pulse width modulation signal when detecting that the OBD connector 111 outputs a positive power signal and detects that the OBD connector 111 outputs a negative power signal.
  • the PMOS transistor Q1 is modulated so that the charge and discharge circuit 2032 outputs the control signal according to the duty ratio of the PMOS transistor Q1.
  • the control signal is a sine wave signal, and the amplitude of the control signal can be changed by setting the duty ratio of the pulse width modulation signal.
  • the controller 204 is electrically connected to the positive pole of the automobile power supply, the negative pole of the automobile power supply, the bias circuit 201, the second switch circuit 202, and the step-down chopper circuit 203 for detecting When the OBD connector 111 outputs a power positive signal, and the OBD connector 111 does not detect that the OBD connector 111 outputs a power negative signal, the controller 204 does not work; when it is detected that the OBD connector 111 outputs a power positive signal, and When it is detected that the OBD connector 111 outputs the negative signal of the power supply, the current detection signal flowing through the second switch circuit 202 is detected, and a pulse width modulation signal is output according to the bias voltage and the current detection signal to control The operating state of the second switch circuit 202 is such that the step-down chopper circuit 203 outputs the control signal.
  • controller 204 calculates the internal voltage drop formed by the PMOS transistor Q1 in the controller 204 according to the current detection signal, and the controller 204 calculates the internal voltage drop of the PMOS transistor Q1 according to the bias voltage and the PMOS transistor Q1.
  • the internal voltage drop of the output pulse width modulation signal is the internal voltage drop formed by the PMOS transistor Q1 in the controller 204 according to the current detection signal, and the controller 204 calculates the internal voltage drop of the PMOS transistor Q1 according to the bias voltage and the PMOS transistor Q1. The internal voltage drop of the output pulse width modulation signal.
  • the controller 204 includes a single-chip microcomputer, and the single-chip microcomputer may adopt 51 series, iOS series, STM32 series, and the like.
  • the single-chip microcomputer includes an input pin, an adjustable voltage pin, a current detection pin, an output pin, a power ground pin, a controller ground pin, and a feedback pin.
  • the input pin is electrically connected to the positive pole of the vehicle power supply for receiving the power supply voltage;
  • the adjustable voltage pin is electrically connected to the bias circuit 201 for receiving the bias voltage;
  • the current detection pin is electrically connected to the second switch circuit 202 and the step-down chopper circuit 203 for obtaining the current detection signal;
  • the output pin is electrically connected to the second switch circuit 202 for To output the pulse width modulation signal;
  • the power ground pin is connected to the negative pole of the vehicle power supply;
  • the controller ground pin is connected to the negative pole of the vehicle power supply;
  • the feedback pin is connected to the voltage sampling circuit 205 The electrical connection is used to receive the voltage sampling signal sent by the voltage sampling circuit 205.
  • the controller 204 may also be a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an ARM (Acorn RISC Machine) or other Programmable logic device, discrete gate or transistor logic, discrete hardware components or any combination of these components; it can also be any traditional processor, controller, microcontroller or state machine; it can also be implemented as a combination of computing devices, For example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.
  • DSP digital signal processor
  • ASIC application specific integrated circuit
  • FPGA field programmable gate array
  • ARM Acorn RISC Machine
  • the voltage sampling circuit 205 is electrically connected to the negative pole of the automobile power supply, the step-down chopper circuit 203, the first switch circuit 10, and the controller 204, and is used to sample the control signal so that all The controller 204 feeds back and adjusts the control signal.
  • the voltage sampling circuit 205 has a second resistor R2 and a third resistor R3.
  • one end of the second resistor R2 is connected to the step-down chopper circuit 203 and the first switch circuit 10, and the other end of the second resistor R2 is connected to one end of the third resistor R3 and the The controller 204 is connected; the other end of the third resistor R3 is connected to the negative pole of the vehicle power supply.
  • the second resistor R2 and the third resistor R3 form a voltage divider circuit, divide the control signal, output a voltage sampling signal, and send the voltage sampling signal to the controller 204, so that the controller 204 feedback and adjusts the control signal according to the voltage sampling signal.
  • the input filter circuit 206 is electrically connected between the positive pole of the automobile power supply and the negative pole of the automobile power supply for filtering the power supply voltage.
  • the input filter circuit 206 includes a third capacitor C3, one end of the third capacitor C3 is connected to the positive pole of the vehicle power supply, and the other end of the third capacitor C3 is connected to the negative pole of the vehicle power supply.
  • the third capacitor C3 is specifically used to filter out spikes and ripple voltages input by the automobile power supply 112, so that the signal waveforms of the power supply voltage input to the bias circuit 201 and the second switch circuit 202 smooth.
  • the input filter circuit 206 is composed of reactive elements, for example, a capacitor is connected in parallel at both ends of the load, or an inductor is connected in series with the load, as well as various multiple filter circuits composed of capacitors and inductors.
  • the voltage sampling circuit 205 and/or the input filter circuit 206 may be omitted.
  • the isolation circuit 100 further includes a slow-start circuit 40, which is electrically connected to the first switch circuit 10 and the diagnostic device 200, and is used for connecting to the first switch circuit 10 and the diagnostic device 200.
  • a slow-start circuit 40 which is electrically connected to the first switch circuit 10 and the diagnostic device 200, and is used for connecting to the first switch circuit 10 and the diagnostic device 200.
  • the slow-start circuit 40 is used to delay processing the power supply voltage output by the automobile power supply 112 to prevent the high-voltage spikes from reaching the diagnostic device 200 and improve the safety of the isolation circuit 100.
  • the embodiment of the present invention provides an isolation circuit, which is electrically connected between the OBD connector of the car to be diagnosed and the diagnostic device of the car diagnostic equipment through a first switch circuit.
  • the OBD connector is also electrically connected to the car power supply of the car to be diagnosed.
  • the switch control circuit is electrically connected to the OBD connector and the first switch circuit respectively, and is used for detecting that the OBD connector outputs the positive signal of the power supply, and the OBD connector outputs the negative signal of the power supply, the switch control circuit does not work to make
  • the first switch circuit works in the off state to keep the diagnostic device not powered on.
  • the OBD connector When it detects that the OBD connector outputs a positive signal of the power supply, and detects that the OBD connector outputs a negative signal of the power supply, it outputs a control signal to enable the first switch
  • the circuit works in a conducting state, so that the vehicle power supply supplies power to the diagnostic device. Therefore, the embodiment of the present invention can avoid poor grounding and improve the reliability of the vehicle diagnostic equipment.

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Abstract

一种隔离电路(100)、汽车诊断设备(300)及汽车诊断系统(500)。其中，隔离电路(100)包括：第一开关电路(10)，电连接于待诊断汽车的OBD连接器(111)和汽车诊断设备(300)的诊断器(200)之间，OBD连接器(111)还与待诊断汽车的汽车电源(112)电连接；开关控制电路(20)，分别与OBD连接器(111)和第一开关电路(10)电连接，用于在检测到OBD连接器(111)输出电源正极信号，且未检测到OBD连接器(111)输出电源负极信号时，开关控制电路(20)不工作，以使第一开关电路(10)工作在关断状态，以保持诊断器(200)未上电；在检测到OBD连接器(111)输出电源正极信号，且检测到OBD连接器(111)输出电源负极信号时，输出控制信号，以使第一开关电路(10)工作在导通状态，以使汽车电源(112)为诊断器(200)供电。能够避免接地不良，提升汽车诊断设备(300)的可靠性。

Description

一种隔离电路、汽车诊断设备及汽车诊断系统
本申请要求于2020年1月3日提交中国专利局、申请号为202010006699.8、申请名称为“一种隔离电路、汽车诊断设备及汽车诊断系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及汽车诊断领域，尤其涉及一种隔离电路、汽车诊断设备及汽车诊断系统。
背景技术
目前，利用汽车诊断设备与待诊断汽车的OBD连接器连接，读取待诊断汽车的故障码，定位发生故障的部位及原因。但是，若待诊断汽车采用非标OBD连接器，虽然待诊断汽车没有故障，由于非标OBD连接器的设计尺寸与标准OBD连接器的设计尺寸存在偏差，可能导致汽车诊断设备与OBD连接器连接时接地不良，即汽车电源正极先于汽车电源负极接入汽车诊断设备，使得待诊断汽车的仪表盘亮故障灯，容易干扰汽车维修人员的判断。
发明内容
本发明实施例旨在提供一种隔离电路、汽车诊断设备及汽车诊断系统，其能够避免接地不良，提升汽车诊断设备的可靠性。
为解决上述技术问题，本发明实施例提供以下技术方案：
在第一方面，本发明实施例提供了一种隔离电路，应用于汽车诊断设备，所述隔离电路包括：
第一开关电路，电连接于待诊断汽车的OBD连接器和所述汽车诊断设备的诊断器之间，所述OBD连接器还与所述待诊断汽车的汽车电源电连接；
开关控制电路，分别与所述OBD连接器和所述第一开关电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且未检测到所述OBD连接器输出电源负极信号时，所述开关控制电路不工作，以使所述第一开关电路工作在关断状态，以保持所述诊断器未上电；在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，输出控制信号，以使所述第一开关电路工作在导通状态，以使所述汽车电源为所述诊断器供电。
可选地，所述汽车电源包括汽车电源正极和汽车电源负极，所述汽车电源正极用于输出所述电源正极信号，所述汽车电源正极用于输出所述电源负极信号，所述开关控制电路包括：
偏置电路，与所述汽车电源正极电连接，用于将所述汽车电源正极输出的电源电压转换为偏置电压；
第二开关电路，与所述汽车电源正极电连接；
降压斩波电路，分别与所述第二开关电路、所述汽车电源负极以及所述第一开关电路电连接；
控制器，分别与所述汽车电源正极、所述汽车电源负极、所述偏置电路、所述第二开关电路以及所述降压斩波电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且未检测到所述OBD连接器输出电源负极信号时，所述控制器不工作；在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，检测流经所述第二开关电路的电流检测信号，根据所述偏置电压和所述电流检测信号，输出脉宽调制信号，以控制所述第二开关电路的工作状态，以使所述降压斩波电路输出所述控制信号。
可选地，所述偏置电路包括第一电阻和第一电容；
所述第一电阻的一端与所述汽车电源正极、所述第一电容的一端以及所述第二开关电路连接，所述第一电阻的另一端与所述第一电容的另一端和所述控制器连接。
可选地，所述第二开关电路包括PMOS管，所述PMOS管的栅极与所述控制器连接，所述PMOS管的源极与所述汽车电源正极连接，所述PMOS管的漏极与所述控制器和所述降压斩波电路连接。
可选地，所述降压斩波电路包括：
续流电路，与所述第二开关电路和所述汽车电源负极电连接，用于当所述第二开关电路工作在导通状态时，所述续流电路工作在关断状态，当所述第二开关电路工作在关断状态时，所述续流电路工作在导通状态；
充放电电路，分别与所述第二开关电路、所述续流电路、所述汽车电源负极以及所述第一开关电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，当所述续流电路工作在关断状态时，实施充电，当所述续流电路工作在导通状态时，实施放电，以输出所述控制信号，并将所述控制信号发送至所述第一开关电路。
可选地，所述续流电路包括二极管，所述二极管的阳极与所述汽车电源负极连接，所述二极管的阴极与所述PMOS管的漏极和所述充放电电路连接。
可选地，所述充放电电路包括电感和第二电容；
所述电感的一端与所述二极管的阴极和所述PMOS管的漏极连接，所述电感的另一端与所述第二电容的一端和所述第一开关电路连接；所述第二电容的另一端与所述汽车电源负极连接。
可选地，所述开关控制电路还包括电压采样电路，分别与所述汽车电源负极、所述降压斩波电路、所述第一开关电路以及所述控制器电连接，用于采样所述控制信号，以使所述控制器反馈调节所述控制信号。
可选地，所述电压采样电路第二电阻和第三电阻；
所述第二电阻的一端与所述降压斩波电路和所述第一开关电路连接，所述第二电阻的另一端与所述第三电阻的一端和所述控制器连接；所述第三电阻的另一端与所述汽车电源负极连接。
可选地，所述开关控制电路还包括输入滤波电路，电连接于所述汽车电源正极和所述汽车电源负极之间，用于对所述电源电压作滤波处理。
可选地，所述输入滤波电路包括第三电容，所述第三电容的一端与所述汽车电源正极连接，所述第三电容的另一端与所述汽车电源负极连接。
可选地，所述隔离电路还包括缓启电路，分别与所述第一开关电路和所述诊断器电连接，用于在所述第一开关电路的工作状态切换为导通状态时，对所述汽车电源输出的电源电压作延时处理。
可选地，所述第一开关电路包括：
第一开关，电连接于所述汽车电源正极和所述诊断器之间，且还与所述开关控制电路电连接，用于根据所述控制信号工作在导通状态；
第二开关，电连接于所述汽车电源负极和所述诊断器之间，且还与所述开关控制电路电连接，用于根据所述控制信号工作在导通状态。
在第二方面，本发明实施例提供了一种汽车诊断设备，包括：
如上任一项所述的隔离电路；
诊断器，与所述隔离电路电连接，还与待诊断汽车通信连接，用于当所述隔离电路工作在导通状态时，根据所述待诊断汽车的汽车电源提供的电源电压，进行工作，并且，获取所述待诊断汽车的诊断数据。
在第三方面，本发明实施例提供了一种汽车诊断系统，包括：
如上所述的汽车诊断设备；
上位机，与所述汽车诊断设备通信连接，用于显示所述汽车诊断设备发送的诊断数据。
本发明的有益效果是：与现有技术相比较，本发明实施例提供了一种隔离电路、汽车诊断设备及汽车诊断系统，通过第一开关电路电连接于待诊断汽车的OBD连接器和汽车诊断设备的诊断器之间，OBD连接器还与待诊断汽车的汽车电源电连接，开关控制电路分别与OBD连接器和第一开关电路电连接，用于在检测到OBD连接器输出电源正极信号，且未检测到OBD连接器输出电源负极信号时，开关控制电路不工作，以使第一开关电路工作在关断状态，以保持诊断器未上电，在检测到OBD连接器输出电源正极信号，且检测到OBD连接器输出电源负极信号时，输出控制信号，以使第一开关电路工作在导通状态，以使汽车电源为诊断器供电，因此，本发明实施例能够避免接地不良，提升汽车诊断设备的可靠性。
附图说明
一个或多个实施例通过与之对应的附图中的图片进行示例性说明，这些示例性说明并不构成对实施例的限定，附图中具有相同参考数字标号的元件表示为类似的元件，除非有特别申明，附图中的图不构成比例限制。
图1为本发明实施例提供的一种汽车诊断系统的结构示意图；
图2为本发明实施例提供的一种汽车诊断设备的结构示意图；
图3为本发明实施例提供的一种隔离电路的结构示意图；
图4为本发明另一实施例提供的一种隔离电路的结构示意图；
图5为本发明实施例提供的一种开关控制电路的结构示意图；
图6为本发明实施例提供的一种开关控制电路的电路连接示意图。
具体实施方式
为了便于理解本申请，下面结合附图和具体实施方式，对本申请进行更详细的说明。需要说明的是，当一个元件被表述“连接”另一个元件，它可以是直接连接到另一个元件、或者其间可以存在一个或多个居中的元件。此外，术语“第一”、“第二”等仅用于描述目的，而不能理解为指示或暗示相对重要性。
除非另有定义，本说明书所使用的所有的技术和科学术语与属于本发明的技术领域的技术人员通常理解的含义相同。在本发明的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是用于限制本发明。本说明书所使用的术语“和/或”包括一个或多个相关的所列项目的任意的和所有的组合。
此外，下面所描述的本申请不同实施例中所涉及的技术特征只要彼此之间未构成冲突就可以相互结合。
请参阅图1，为本发明实施例提供的一种汽车诊断系统的结构示意图。如图1所示，所述汽车诊断系统500包括如下述设备实施例所述的汽车诊断设备300和上位机400，所述上位机400与所述汽车诊断设备300通信连接，用于显示所述汽车诊断设备300发送的诊断数据。
本发明实施例提供的一种汽车诊断系统，通过汽车诊断设备，避免了接地不良的现象，进而提升了诊断可靠性。
请参阅图2，为本发明实施例提供的一种汽车诊断设备的结构示意图。如图2所示，所述汽车诊断设备300包括如下述电路实施例所述的隔离电路100和诊断器200。所述诊断器200与所述隔离电路100电连接，还与待诊断汽车11通信连接，用于当所述隔离电路100工作在导通状态时，根据所述待诊断汽车11的汽车电源112提供的电源电压，进行工作，并且，获取所述待诊断汽车11的诊断数据。
其中，所述待诊断汽车11包括OBD连接器111、汽车电源112以及车载自动诊断系统(图未示)。所述汽车电源112包括汽车电源正极和汽车电源负极，所述汽车电源正极用于输出所述电源正极信号，所述汽车电源正极用于输出所述电源负极信号。
在所述待诊断汽车11内部，所述OBD连接器111分别与所述汽车电源正极以及所述汽车电源负极电连接。当所述汽车诊断设备300与所述待诊断汽车11连接时，所述OBD连接器111与所述隔离电路100电连接，且与所述诊断器200通信连接。若所述OBD连接器111与所述隔离电路100正常连接，所述隔离电路100用于使所述汽车电源112通过所述隔离电路100为所述诊断器200提供电源，当所述诊断器200上电后，通过所述OBD连接器111获取所述 待诊断汽车11的诊断数据；若所述OBD连接器111与所述隔离电路100接地不良，所述隔离电路100用于切断所述汽车电源112与所述诊断器200的供电回路，以保持所述诊断器200未上电。
所述汽车电源112用于为所述待诊断汽车11中所有用电设备提供低压直流电源(通常汽油车为12V，柴油车为24V)，使所述待诊断汽车11各部分能正常工作，当所述汽车诊断设备300与所述待诊断汽车11连接时，所述汽车电源112还用于为所述汽车诊断设备300提供电源。
所述车载自动诊断系统还与所述OBD连接器111电连接(图未示)，用于监控所述待诊断汽车11，生成诊断数据，并且，当所述诊断器200上电后，通过所述OBD连接器111将所述诊断数据发送至所述诊断器200。
具体的，所述电源正极信号和所述电源负极信号通过所述OBD连接器111到达所述隔离电路100，所述隔离电路100用于检测所述电源正极信号和所述电源负极信号，在检测到所述OBD连接器111输出电源正极信号，且未检测到所述OBD连接器111输出电源负极信号时，保持所述诊断器200未上电；在检测到所述OBD连接器111输出电源正极信号，且检测到所述OBD连接器111输出电源负极信号时，使所述汽车电源112为所述诊断器200供电。
本发明实施例提供的一种汽车诊断设备，通过隔离电路，能够避免汽车诊断设备接地不良，进而提升了汽车诊断设备的可靠性。
请参阅图3，为本发明实施例提供的一种隔离电路的结构示意图。如图3所示，所述隔离电路100应用于汽车诊断设备300，包括第一开关电路10和开关控制电路20。
所述第一开关电路10电连接于待诊断汽车11的OBD连接器111和所述汽车诊断设备300的诊断器200之间，所述OBD连接器111还与所述待诊断汽车11的汽车电源112电连接。
请参阅图4和图5，所述第一开关电路10包括第一开关101和第二开关102。
所述第一开关101电连接于所述汽车电源正极和所述诊断器200之间，且还与所述开关控制电路20电连接，用于根据所述控制信号工作在导通状态。
所述第二开关102电连接于所述汽车电源负极和所述诊断器200之间，且还与开关控制电路20电连接，用于根据所述控制信号工作在导通状态。
在本实施例中，所述第一开关101和所述第二开关102为常闭开关。其根据所述控制信号工作在导通状态，当所述控制器204不工作时，恢复常闭状态。
可以理解，当所述第一开关101和所述第二开关102均工作在导通状态时，所述第一开关101和所述第二开关102通过所述待诊断汽车11的OBD连接器111分别与所述汽车电源正极和所述汽车电源负极电连接，以使所述待诊断汽车11的汽车电源112提供的电源电压通过所述OBD连接器111，到达所述第一开关101、所述第二开关102以及所述开关控制电路20，为所述第一开关101、所述第二开关102述以及所述开关控制电路20提供电源。
在一些实施例中，所述第一开关101和所述第二开关102包括金属-氧化物半导体场效应晶体管、双极型三极管、继电器、其他晶体管组成的开关电路等。此时，当所述控制器204不工作时，所述控制器204与所述第一开关101和所述第二开关102对应的输出引脚置低，所述开关控制电路20不输出控制信号，以使所述第一开关101和所述第二开关102工作在关断状态；当所述控制器204工作时，所述控制器204与所述第一开关101和所述第二开关102对应的输出引脚输出脉宽调制信号，所述开关控制电路20输出控制信号，以使所述第一开关101和所述第二开关102工作在导通状态。
所述开关控制电路20分别与所述OBD连接器111和所述第一开关电路10电连接，用于在检测到所述OBD连接器111输出电源正极信号，且未检测到所述OBD连接器111输出电源负极信号时，所述开关控制电路20不工作，以使所述第一开关电路10工作在关断状态，以保持所述诊断器200未上电；在检测到所述OBD连接器111输出电源正极信号，且检测到所述OBD连接器111输出电源负极信号时，输出控制信号，以使所述第一开关电路10工作在导通状态，以使所述汽车电源112为所述诊断器200供电。
其中，开关控制电路20检测到所述OBD连接器111输出电源正极信号，且未检测到所述OBD连接器111输出电源负极信号包括以下情况：所述汽车电源正极先于所述汽车电源负极接入所述隔离电路100。开关控制电路20检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号包括以下两种情况：一、所述汽车电源正极和所述汽车电源负极同时接入所述隔离电路100；二、所述汽车电源正极后于所述汽车电源负极接入所述隔离电路100。
可见，当开关控制电路20检测到所述OBD连接器111输出电源正极信号，且未检测到所述OBD连接器111输出电源负极信号，此时，所述汽车电源正极为所述开关控制电路20提供输入电压，由于所述开关控制电路20未接地，所述开关控制电路20不工作，使所述第一开关电路10工作在关断状态，以切断所述汽车电源112与所述诊断器200的供电回路，保持所述诊断器200未上电。紧接着，人为调整所述汽车诊断设备300与所述OBD连接器111的连接，例如，重新拔插所述汽车诊断设备300，使得当开关控制电路20检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号，此时，所述汽车电源正极为所述开关控制电路20提供输入电压，所述开关控制电路20接地，所述开关控制电路20输出控制信号，使所述第一开关电路10根据所述控制信号，工作在导通状态，以使汽车电源112通过所述隔离电路100为所述诊断器200提供电源。从而，避免了接地不良使电压浮高或产生火花放电，导致所述待诊断汽车11检测到外部高压脉冲而触发报警问题。
请再次参阅图5，所述开关控制电路20包括偏置电路201、第二开关电路202、降压斩波电路203、控制器204、电压采样电路205以及输入滤波电路206。
所述偏置电路201与所述汽车电源正极电连接，用于将所述汽车电源正极输出的电源电压转换为偏置电压。
请一并参阅图6，所述偏置电路201包括第一电阻R1和第一电容C1。
其中，所述第一电阻R1的一端与所述汽车电源正极、所述第一电容C1的一端以及所述第二开关电路202连接，所述第一电阻R1的另一端与所述第一电容C1的另一端和所述控制器204连接。
所述控制器204包括恒流电流源，用于提供恒定电流i，恒定电流i在所述第一电阻R1上形成压降，即偏置电压V，其中，偏置电压V＝R1*i，并且，将偏置电压V发送至所述控制器204。另外，所述电源电压在所述第一电阻R1和所述第一电容C1的容积作用下缓慢启动，避免尖峰电压对所述控制器204的影响，保护所述控制器204不被烧坏。
所述第二开关电路202与所述汽车电源正极电连接。
其中，所述第二开关电路202包括PMOS管Q1，所述PMOS管Q1的栅极与所述控制器204连接，所述PMOS管Q1的源极与所述汽车电源正极连接，所述PMOS管Q1的漏极与所述控制器204和所述降压斩波电路203连接。
在一些实施例中，所述第二开关电路202还包括电阻和/或电容等元器件，用于限制所述PMOS管Q1的栅源电压，避免所述PMOS管Q1由于栅源电压过高被击穿。
所述降压斩波电路203分别与所述第二开关电路202、所述汽车电源负极以及所述第一开关电路10电连接。
在本实施例中，所述降压斩波电路203包括续流电路2031和充放电电路2032。
所述续流电路2031与所述第二开关电路202和所述汽车电源负极电连接，用于当所述第二开关电路202工作在导通状态时，所述续流电路2031工作在关断状态，当所述第二开关电路202工作在关断状态时，所述续流电路2031工作在导通状态。
如图6所示，所述续流电路2031包括二极管D1，所述二极管D1的阳极与所述汽车电源负极连接，所述二极管D1的阴极与所述PMOS管Q1的漏极和所述充放电电路2032连接。
所述充放电电路2032分别与所述第二开关电路202、所述续流电路2031、所述汽车电源负极以及所述第一开关电路10电连接，用于在检测到所述OBD连接器111输出电源正极信号，且检测到所述OBD连接器111输出电源负极信号时，当所述续流电路2031工作在关断状态时，实施充电，当所述续流电路2031工作在导通状态时，实施放电，以输出所述控制信号，并将所述控制信号发送至所述第一开关电路10。
如图6所示，所述充放电电路2032包括电感L1和第二电容C2。
其中，所述电感L1的一端与所述二极管D1的阴极和所述PMOS管Q1的漏极连接，所述电感L1的另一端与所述第二电容C2的一端和所述第一开关电路 10连接；所述第二电容C2的另一端与所述汽车电源负极连接。
具体的，所述脉宽调制信号用于调制所述PMOS管Q1的占空比。当所述PMOS管Q1处于导通ton期间，所述二极管D1反偏，所述电源电压经过所述电感L1充电给所述第一开关电路10充电，此时，流经所述电感L1的电流iL增加，所述电感L1的储能增加，假设所述电源电压为E，所述第一开关电路10两端电压为u0，则在所述电感L1的两端有一个正向电压Ul＝E-u0，Ul使得电流iL线性增加。当所述PMOS管Q1处于截止toff期间，所述电感L1产生感应电动势，所述二极管D1导通，电流iL经所述二极管D1续流，此时，Ul＝-u0，所述电感L1向所述第一开关电路10供电，电感储能逐步消耗，电流iL线性下降。
可以理解，所述电感L1的电感值和所述第二电容C2的电容值需设置稍大一些。在本实施例中，所述控制器204在检测到所述OBD连接器111输出电源正极信号，且检测到所述OBD连接器111输出电源负极信号时，输出所述脉宽调制信号，用以调制所述PMOS管Q1，以使所述充放电电路2032根据所述PMOS管Q1的占空比，输出所述控制信号。其中，所述控制信号为正弦波信号，通过设置所述脉宽调制信号的占空比，可改变所述控制信号的幅度等。
所述控制器204分别与所述汽车电源正极、所述汽车电源负极、所述偏置电路201、所述第二开关电路202以及所述降压斩波电路203电连接，用于在检测到所述OBD连接器111输出电源正极信号，且未检测到所述OBD连接器111输出电源负极信号时，所述控制器204不工作；在检测到所述OBD连接器111输出电源正极信号，且检测到所述OBD连接器111输出电源负极信号时，检测流经所述第二开关电路202的电流检测信号，根据所述偏置电压和所述电流检测信号，输出脉宽调制信号，以控制所述第二开关电路202的工作状态，以使所述降压斩波电路203输出所述控制信号。
可以理解，所述控制器204根据所述电流检测信号，计算所述PMOS管Q1在所述控制器204形成的内部压降，所述控制器204根据所述偏置电压和所述PMOS管Q1的内部压降，输出脉宽调制信号。
在本实施例中，所述控制器204包括单片机，所述单片机可以采用51系列、Arduino系列、STM32系列等。
其中，所述单片机包括输入引脚、可调电压引脚、电流检测引脚、输出引脚、电源接地引脚、控制器接地引脚以及反馈引脚。所述输入引脚与所述汽车电源正极电连接，用于接收所述电源电压；所述可调电压引脚与所述偏置电路201电连接，用于接收所述偏置电压；所述电流检测引脚与所述第二开关电路202和所述降压斩波电路203电连接，用于获取所述电流检测信号；所述输出引脚与所述第二开关电路202电连接，用于输出所述脉宽调制信号；所述电源接地引脚与所述汽车电源负极连接；所述控制器接地引脚与所述汽车电源负极连接；所述反馈引脚与所述电压采样电路205电连接，用于接收所述电压采样电路205发送的电压采样信号。
在一些实施例中，所述控制器204还可以为通用处理器、数字信号处理器(DSP)、专用集成电路(ASIC)、现场可编程门阵列(FPGA)、ARM(Acorn RISC Machine)或其它可编程逻辑器件、分立门或晶体管逻辑、分立的硬件组件或者这些部件的任何组合；还可以是任何传统处理器、控制器、微控制器或状态机；也可以被实现为计算设备的组合，例如，DSP和微处理器的组合、多个微处理器、一个或多个微处理器结合DSP核、或任何其它这种配置。
所述电压采样电路205分别与所述汽车电源负极、所述降压斩波电路203、所述第一开关电路10以及所述控制器204电连接，用于采样所述控制信号，以使所述控制器204反馈调节所述控制信号。
如图6所示，所述电压采样电路205第二电阻R2和第三电阻R3。
其中，所述第二电阻R2的一端与所述降压斩波电路203和所述第一开关电路10连接，所述第二电阻R2的另一端与所述第三电阻R3的一端和所述控制器204连接；所述第三电阻R3的另一端与所述汽车电源负极连接。
具体的，所述第二电阻R2和所述第三电阻R3构成一分压电路，对所述控制信号作分压处理，输出电压采样信号，并将所述电压采样信号发送至所述控制器204，以使所述控制器204根据所述电压采样信号，反馈调节所述控制信号。
所述输入滤波电路206电连接于所述汽车电源正极和所述汽车电源负极之间，用于对所述电源电压作滤波处理。
其中，所述输入滤波电路206包括第三电容C3，所述第三电容C3的一端与所述汽车电源正极连接，所述第三电容C3的另一端与所述汽车电源负极连接。所述第三电容C3具体用于滤除所述汽车电源112输入的尖峰脉冲和纹波电压，使输入至所述偏置电路201和所述第二开关电路202的所述电源电压的信号波形平滑。
在一些实施例中，所述输入滤波电路206由电抗元件组成，例如，在负载两端并联电容器，或者与负载串联电感器，以及电容、电感组成而成的各种复式滤波电路。
可以理解，所述电压采样电路205和/或所述输入滤波电路206可省略。
在一些实施例中，请参阅图4，所述隔离电路100还包括缓启电路40，分别与所述第一开关电路10和所述诊断器200电连接，用于在所述第一开关电路10的工作状态切换为导通状态时，对所述汽车电源112输出的电源电压作延时处理。
可以理解，在所述第一开关电路10打开瞬间，产生高压尖峰脉冲，若所述汽车电源112输出的电源电压通过所述第一开关电路10直接作用于所述诊断器200，则所述高压尖峰脉冲也输入至所述诊断器200，可能烧坏或击穿所述诊断器200的内部元器件。采用所述缓启电路40对所述汽车电源112输出的电源电压作延时处理，避免所述高压尖峰脉冲到达所述诊断器200，提升了所述隔离电路100的安全性。
本发明实施例提供了一种隔离电路，通过第一开关电路电连接于待诊断汽车的OBD连接器和汽车诊断设备的诊断器之间，OBD连接器还与待诊断汽车的汽车电源电连接，开关控制电路分别与OBD连接器和第一开关电路电连接，用于在检测到OBD连接器输出电源正极信号，且未检测到OBD连接器输出电源负极信号时，开关控制电路不工作，以使第一开关电路工作在关断状态，以保持诊断器未上电，在检测到OBD连接器输出电源正极信号，且检测到OBD连接器输出电源负极信号时，输出控制信号，以使第一开关电路工作在导通状态，以使汽车电源为诊断器供电，因此，本发明实施例能够避免接地不良，提升汽车诊断设备的可靠性。
最后应说明的是：以上实施例仅用以说明本发明的技术方案，而非对其限制；在本发明的思路下，以上实施例或者不同实施例中的技术特征之间也可以进行组合，步骤可以以任意顺序实现，并存在如上所述的本发明的不同方面的许多其它变化，为了简明，它们没有在细节中提供；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。

Claims (15)

  1. 一种隔离电路，应用于汽车诊断设备，其特征在于，所述隔离电路包括：
    第一开关电路，电连接于待诊断汽车的OBD连接器和所述汽车诊断设备的诊断器之间，所述OBD连接器还与所述待诊断汽车的汽车电源电连接；
    开关控制电路，分别与所述OBD连接器和所述第一开关电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且未检测到所述OBD连接器输出电源负极信号时，所述开关控制电路不工作，以使所述第一开关电路工作在关断状态，以保持所述诊断器未上电；在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，输出控制信号，以使所述第一开关电路工作在导通状态，以使所述汽车电源为所述诊断器供电。
  2. 根据权利要求1所述的隔离电路，其特征在于，所述汽车电源包括汽车电源正极和汽车电源负极，所述汽车电源正极用于输出所述电源正极信号，所述汽车电源正极用于输出所述电源负极信号，所述开关控制电路包括：
    偏置电路，与所述汽车电源正极电连接，用于将所述汽车电源正极输出的电源电压转换为偏置电压；
    第二开关电路，与所述汽车电源正极电连接；
    降压斩波电路，分别与所述第二开关电路、所述汽车电源负极以及所述第一开关电路电连接；
    控制器，分别与所述汽车电源正极、所述汽车电源负极、所述偏置电路、所述第二开关电路以及所述降压斩波电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且未检测到所述OBD连接器输出电源负极信号时，所述控制器不工作；在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，检测流经所述第二开关电路的电流检测信号，根据所述偏置电压和所述电流检测信号，输出脉宽调制信号，以控制所述第二开关电路的工作状态，以使所述降压斩波电路输出所述控制信号。
  3. 根据权利要求2所述的隔离电路，其特征在于，所述偏置电路包括第一电阻和第一电容；
    所述第一电阻的一端与所述汽车电源正极、所述第一电容的一端以及所述第二开关电路连接，所述第一电阻的另一端与所述第一电容的另一端和所述控制器连接。
  4. 根据权利要求2所述的隔离电路，其特征在于，所述第二开关电路包括PMOS管，所述PMOS管的栅极与所述控制器连接，所述PMOS管的源极与所述汽车电源正极连接，所述PMOS管的漏极与所述控制器和所述降压斩波电路连接。
  5. 根据权利要求4所述的隔离电路，其特征在于，所述降压斩波电路包括：
    续流电路，与所述第二开关电路和所述汽车电源负极电连接，用于当所述第二开关电路工作在导通状态时，所述续流电路工作在关断状态，当所述第二开关电路工作在关断状态时，所述续流电路工作在导通状态；
    充放电电路，分别与所述第二开关电路、所述续流电路、所述汽车电源负极以及所述第一开关电路电连接，用于在检测到所述OBD连接器输出电源正极信号，且检测到所述OBD连接器输出电源负极信号时，当所述续流电路工作在关断状态时，实施充电，当所述续流电路工作在导通状态时，实施放电，以输出所述控制信号，并将所述控制信号发送至所述第一开关电路。
  6. 根据权利要求5所述的隔离电路，其特征在于，所述续流电路包括二极管，所述二极管的阳极与所述汽车电源负极连接，所述二极管的阴极与所述PMOS管的漏极和所述充放电电路连接。
  7. 根据权利要求6所述的隔离电路，其特征在于，所述充放电电路包括电感和第二电容；
    所述电感的一端与所述二极管的阴极和所述PMOS管的漏极连接，所述电感的另一端与所述第二电容的一端和所述第一开关电路连接；所述第二电容的另一端与所述汽车电源负极连接。
  8. 根据权利要求2所述的隔离电路，其特征在于，所述开关控制电路还包括电压采样电路，分别与所述汽车电源负极、所述降压斩波电路、所述第一开关电路以及所述控制器电连接，用于采样所述控制信号，以使所述控制器反馈调节所述控制信号。
  9. 根据权利要求8所述的隔离电路，其特征在于，所述电压采样电路第二电阻和第三电阻；
    所述第二电阻的一端与所述降压斩波电路和所述第一开关电路连接，所述第二电阻的另一端与所述第三电阻的一端和所述控制器连接；所述第三电阻的另一端与所述汽车电源负极连接。
  10. 根据权利要求8所述的隔离电路，其特征在于，所述开关控制电路还包括输入滤波电路，电连接于所述汽车电源正极和所述汽车电源负极之间，用于对所述电源电压作滤波处理。
  11. 根据权利要求10所述的隔离电路，其特征在于，所述输入滤波电路包括第三电容，所述第三电容的一端与所述汽车电源正极连接，所述第三电容的另一端与所述汽车电源负极连接。
  12. 根据权利要求1-11任一项所述的隔离电路，其特征在于，所述隔离电路还包括缓启电路，分别与所述第一开关电路和所述诊断器电连接，用于在所述第一开关电路的工作状态切换为导通状态时，对所述汽车电源输出的电源电压作延时处理。
  13. 根据权利要求2-11任一项所述的隔离电路，其特征在于，所述第一开关电路包括：
    第一开关，电连接于所述汽车电源正极和所述诊断器之间，且还与所述开 关控制电路电连接，用于根据所述控制信号工作在导通状态；
    第二开关，电连接于所述汽车电源负极和所述诊断器之间，且还与所述开关控制电路电连接，用于根据所述控制信号工作在导通状态。
  14. 一种汽车诊断设备，其特征在于，包括：
    如权利要求1-13任一项所述的隔离电路；
    诊断器，与所述隔离电路电连接，还与待诊断汽车通信连接，用于当所述隔离电路工作在导通状态时，根据所述待诊断汽车的汽车电源提供的电源电压，进行工作，并且，获取所述待诊断汽车的诊断数据。
  15. 一种汽车诊断系统，其特征在于，包括：
    如权利要求14所述的汽车诊断设备；
    上位机，与所述汽车诊断设备通信连接，用于显示所述汽车诊断设备发送的诊断数据。
PCT/CN2020/133795 2020-01-03 2020-12-04 一种隔离电路、汽车诊断设备及汽车诊断系统 WO2021135814A1 (zh)

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