Vehicle-mounted eFuse circuit with function safety and control method

Abstract

The invention discloses a vehicle-mounted eFuse circuit with functional safety and a control method. The vehicle-mounted eFuse circuit comprises a pre-charging control circuit module, a positive power switch tube circuit module, a negative power switch tube circuit module, a negative PTC heating control circuit module, a driving circuit module, a microcontroller module, a sampling circuit module and a power supply module. The driving circuit module receives a control signal from the microcontroller module and a control signal output by the sampling circuit module, drives and controls on and off of power switch tubes in the power switch tube modules, and disconnects or connects a current path by controlling on and off of the switch tubes. And a traditional fuse is replaced in response to an abnormal condition in a circuit.

Description

Technical Field

[0001] The present invention relates to an automotive electrical system, and in particular to an on-vehicle eFuse circuit with functional safety and a control method. Background Art

[0002] The battery, motor, and electronic control technology of new energy vehicles are the core technologies of electric vehicles. With the rise of intelligent driving and domain controllers, the safety, reliability, and intelligence of electrical systems are required to be higher, and the diagnostic requirements for electrical circuits are getting higher and higher. The new energy vehicle industry is undergoing a transition from traditional hardware-oriented to software-defined vehicles, and traditional fuses can no longer meet these requirements.

[0003] eFuse (electronic fuse) is an integrated protection circuit used to limit circuit current and voltage to a safe level in the event of a fault. As a more advanced circuit protection device, eFuse came into being in the electronic control system of new energy vehicles. Compared with traditional fuses, eFuse has many advantages, such as long life, fast response speed, self-recovery, small size, rich functions, and low maintenance cost. Therefore, eFuse plays an important role in the iteration of autonomous driving, low-voltage system upgrades, and E / E architecture improvements. At present, compact eFuse is used in new energy vehicles to replace traditional fuses and relays, thereby providing more precise protection for the electronic control system of new energy vehicles and realizing programmable and diagnosable power supply. At the same time, it also provides support for the intelligence and efficiency of automotive electrical systems. Summary of the invention

[0004] The embodiments of the present application provide a functionally safe on-board eFuse circuit and control method, which disconnects or connects the current path by controlling the on-off of a switch tube to respond to abnormal conditions in the circuit, thereby replacing traditional fuses and achieving efficient, precise, safe and intelligent control of the automotive electrical system.

[0005] The present application provides a functionally safe vehicle-mounted eFuse circuit, including a pre-charge control circuit module, a positive power switch tube circuit module, a negative power switch tube circuit module, a negative PTC heating control circuit module, a drive circuit module, a microcontroller module, a sampling circuit module, a voltage protection module, a current protection module, and a power supply module; the power supply module supplies power to the sampling circuit module, the microcontroller module, and the drive circuit module; the drive circuit module receives a control signal from the microcontroller module and a control signal output from the sampling circuit module, and is used to drive and control the conduction and cutoff of the power switch tubes in each power switch tube module;

[0006] The positive power switch tube circuit module is composed of a group of positive charging power switch tubes and a group of positive discharging power switch tubes back to back, and the negative power switch tube circuit module is composed of a group of negative charging power switch tubes and a group of negative discharging power switch tubes back to back. The positive discharge power switch tube is connected to the positive electrode of the vehicle-mounted power battery, and the output side of the positive charging power switch tube is used to connect to the positive electrode of the vehicle-mounted high-voltage load. One end of the negative charging power switch tube is connected to the negative electrode of the vehicle-mounted power battery, and one end of the negative discharge power switch tube is used to connect to the negative electrode of the vehicle-mounted high-voltage load.

[0007] Preferably, the sampling circuit module includes: a positive sampling circuit and a negative sampling circuit.

[0008] Preferably, the sampling circuit module includes: a signal amplification circuit, an overcurrent detection circuit, a signal control circuit, a system reset circuit, and a limit value preset circuit;

[0009] The signal amplification circuit is used to amplify the collected current signal and input it into the overcurrent detection circuit; the overcurrent detection circuit receives the voltage signal of the amplified current information of the signal amplification circuit, and determines whether there is an overcurrent according to a preset limit value. When the comparator detects an overcurrent signal, a primary shutdown signal is generated to control the switch tube to disconnect; the primary shutdown signal is simultaneously applied to the microcontroller module to generate a secondary shutdown signal, which controls the power switch tube to shut down again to realize the overcurrent protection function; the system reset circuit performs a system reset after an overcurrent; the limit value preset circuit sets the overcurrent state limit value.

[0010] Preferably, the overcurrent detection circuit includes a detection comparison circuit and an overcurrent locking circuit.

[0011] Preferably, the detection and comparison circuit includes two comparators, which respectively perform charging upper limit overcurrent detection and discharging upper limit overcurrent detection.

[0012] Preferably, the overcurrent locking circuit is a positive feedback circuit structure, including an ultrafast recovery diode.

[0013] The present application also provides a vehicle-mounted eFuse circuit control method with functional safety, comprising:

[0014] Step S1, monitoring the current signal of the sampling resistor, inputting it into the signal amplification circuit, and outputting it to the overcurrent detection circuit after being amplified by the operational amplifier;

[0015] Step S2, the limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input to the overcurrent detection circuit to determine whether the current exceeds the limit;

[0016] Step S3, the comparator in the overcurrent detection circuit performs charge and discharge upper limit overcurrent detection. When the comparator detects an overcurrent signal, it generates a primary shutdown signal to control the switch tube to be disconnected; the primary shutdown signal is simultaneously applied to the microcontroller module to generate a secondary shutdown signal, which controls the power switch tube to be turned off again to achieve an overcurrent protection function; at the same time, the comparator is connected in parallel with a diode to achieve overcurrent state locking;

[0017] Step S4, when an overcurrent circuit is detected and the vehicle system is inspected and troubleshooted, the system reset circuit inputs a reset signal to reset the on-board eFuse.

[0018] The technical solution provided in the embodiments of the present application has the following technical effects:

[0019] 1. This application uses a positive and negative power switch tube circuit module to replace the traditional fuse, and through the overcurrent detection circuit and the two overcurrent controls of the microcontroller module, the switch tube is controlled to disconnect or connect the current path and respond to abnormal conditions in the circuit. A pre-charge control circuit module is also set up. During the charging and discharging process of the switch tube, a pre-charge circuit is added to ensure that the bus is slowly established, prevent large starting current shocks, and ensure load safety.

[0020] 2. This application can complete overcurrent judgment and overcurrent state locking by setting comparators and diodes in the sampling circuit module, making the entire system safer and more efficient; the overcurrent state limit value in this application can be independently set through the limit value preset circuit according to actual needs, so that different vehicles and different states can use this system; this application also sets a system reset circuit, which can achieve one-button overcurrent lock reset after maintenance, making the operation simpler and more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a system diagram of the vehicle-mounted eFuse circuit for this application;

[0022] Figure 2 This is the system diagram of the current sampling module for this application;

[0023] Figure 3 This is the positive electrode charge and discharge monitoring circuit diagram of this application;

[0024] Figure 4 This is the negative electrode charge and discharge monitoring circuit diagram of this application;

[0025] Figure 5 This is a circuit diagram for setting the overcurrent signal limit value of this application;

[0026] Figure 6 This is a flow chart of the vehicle-mounted eFuse control method for this application. DETAILED DESCRIPTION

[0027] The embodiments of the present application provide a functionally safe on-board eFuse circuit and control method to replace traditional mechanical fuses, independently realize pre-charge control, charge control, and discharge control for the positive and negative electrodes of the vehicle's high-voltage battery, and achieve the ASIL D safety level through the design of redundant sampling and protection circuits.

[0028] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0029] Embodiment 1

[0030] like Figure 1 As shown, the vehicle-mounted eFuse circuit includes a pre-charge control circuit module, a positive power switch tube circuit module, a negative power switch tube circuit module, a negative PTC heating control circuit module, a switch tube drive circuit module, a microcontroller module, a current sampling module, and a power supply module. The power supply module supplies power to the sampling circuit module, the microcontroller module, the drive circuit module, the voltage protection module, and the current protection module; the switch tube drive circuit module receives a control signal from the microcontroller module to drive and control the conduction and cutoff of the power switch tubes in each power switch tube module.

[0031] The positive power switch tube circuit module is composed of a group of positive charging power switch tubes and a group of positive discharging power switch tubes back to back, and the negative power switch tube circuit module is composed of a group of negative charging power switch tubes and a group of negative discharging power switch tubes back to back. The positive discharging power switch tubes Q1 and Q2 are connected to the positive pole of the vehicle power battery, and the output side of the positive charging power switch tubes Q3 and Q4 is used to connect the positive pole of the vehicle high-voltage load. The negative charging power switch tubes Q6 and Q7 are connected to the negative pole of the vehicle power battery, and the negative discharging power switch tubes Q8 and Q9 are connected to the negative pole of the vehicle high-voltage load. The positive discharge power switch tubes Q1 and Q2 are driven by gate drive 1 to realize the opening and closing of the positive discharge switch tube. The positive charging power switch tubes Q3 and Q4 are driven by gate drive 2 to realize the opening and closing of the positive charging switch tube. The negative charging power switch tubes Q6 and Q7 are driven by gate drive 4 to realize the opening and closing of the negative charging switch tube. The negative discharge power switch tubes Q8 and Q9 are driven by the gate driver 5 to realize the opening and closing of the negative discharge switch tubes.

[0032] The pre-charge control circuit module includes a pre-charge resistor and a pre-charge power switch tube Q3. One end of the pre-charge resistor is used to connect to the positive electrode of the vehicle power battery, and the other end is connected to the pre-charge power switch tube Q3. The other end of the pre-charge power switch tube is connected to the output side of the positive discharge power switch tube. The pre-charge switch tube Q3 is driven and controlled by the gate driver 3 to perform a switching action to realize the pre-charge function. The pre-charge resistor is used to limit the pre-charge current. When a gate drive failure occurs, the gate driver 3 outputs a fault signal to the controller.

[0033] A positive current sampling module 1 is connected in series between the positive charging power switch tube and the positive discharging power switch tube; a negative current sampling module 2 is connected in series between the negative charging power switch tube and the negative discharging power switch tube; the current information detected by the positive current detection module and the negative current detection module is transmitted to the microcontroller module in real time.

[0034] The negative electrode PTC heating control circuit module includes a PTC heater and a power switch tube Q10 for controlling the start and stop of heating. One end of the power switch tube Q10 for controlling the start and stop of heating is connected to the current input side of the negative electrode current sampling module, and the other end is connected to the PTC heater. The power switch tube for controlling the start and stop of heating is controlled by the microcontroller module, and the gate drive 6 drives the power switch tube Q10 for starting and stopping heating to perform switching action to realize the PTC heating function.

[0035] The power supply modules can realize independent power supply of the gate drivers respectively. Due to the existence of the self-recovery fuse, the damage of all power supplies will not affect other branch power supplies, thereby enhancing the reliability of the system.

[0036] like Figure 2 As shown, the current sampling module includes a signal amplification circuit, an overcurrent detection circuit, a signal control circuit, a system reset circuit, and a limit value preset circuit; the overcurrent detection circuit includes a detection comparison circuit and an overcurrent locking circuit.

[0037] like Figure 3 As shown, the current sampling module 1 monitors the current signal POS_IS+ of the positive sampling resistor, and the current signal POS_IS+ is input to the signal amplification circuit of the microcontroller module. The current signal POS_IS+ represents the current flowing through the positive sampling resistor; the current signal POS_IS+ is a differential signal, which is amplified by the operational amplifier U2B and input to the overcurrent detection circuit;

[0038] The signal recognition circuit includes an operational comparator U2A, a comparator U2C, a diode D1, a diode D2, a diode D3, and a diode D4; the comparator U2A performs a charge upper limit overcurrent detection, and the comparator U2A compares the sampled current signal with the limit value input in P_SC2REF to determine whether the current reaches the charge upper limit; the comparator U2C performs a discharge upper limit overcurrent detection, and the comparator U2C compares the sampled current signal with the limit value input in P_SC1REF to determine whether the current reaches the discharge upper limit; when the comparator U2A detects an overcurrent signal, the output terminal 1 of the comparator U2A outputs a high-level signal, that is, a primary shutdown signal controls the switch tube to be disconnected; at the same time, when the comparator U2A detects an overcurrent signal, the high-level signal acts on the resistor R4 of the signal control circuit through the diode D1, and the transistor Q1 is forced to turn on under the action of the high-level signal, so the POS_EN signal is grounded after passing through R2, and then the POS_EN signal is pulled down, that is, the secondary shutdown signal, and the positive switch tube and the negative switch tube are controlled to be turned off again to realize the overcurrent protection function. Through the independent control of the charging and discharging power switch tubes, a higher level of functional safety is achieved, and the overcurrent state is maintained under the action of the switch tube D2 to achieve the locking function. When the comparator U2C detects an overcurrent signal, the output terminal 8 of the comparator U2C outputs a high-level signal, that is, the primary shutdown signal controls the switch tube to disconnect; at the same time, when the comparator U2C detects an overcurrent signal, the high-level signal acts on the resistor R4 of the signal control circuit through the diode D3. Under the action of the high-level signal, the transistor Q1 is forced to turn on, so the POS_EN signal is grounded after R2, and then the POS_EN signal is pulled down, that is, the secondary shutdown signal, and the positive switch tube and the negative switch tube are controlled to be turned off again to achieve the overcurrent protection function. And the overcurrent state is maintained under the action of the switch tube D4 to achieve the locking function.

[0039] When an overcurrent condition occurs, after the vehicle system is repaired and the fault is eliminated, the system reset circuit inputs a reset signal to POS_RST to achieve overcurrent protection lock reset of the entire eFuse circuit.

[0040] like Figure 5 As shown, the limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input into N_SC2REF and N_SC1REF, and is used by comparator U4A and comparator U4C to determine whether the current exceeds the limit.

[0041] like Figure 4As shown, the current sampling module 2 monitors the current signal NEG_IS+ of the negative electrode sampling resistor, and the current signal NEG_IS+ is input to the signal amplification circuit of the microcontroller module. The current signal NEG_IS+ represents the current flowing through the negative electrode sampling resistor; the current signal NEG_IS+ is a differential signal, which is amplified by the operational amplifier U4B and input to the overcurrent detection circuit;

[0042] The signal recognition circuit includes an operational comparator U4A, a comparator U4C, a diode D5, a diode D6, a diode D7, and a diode D8; the comparator U4A performs a charging upper limit overcurrent detection, and the comparator U2A compares the sampled current signal with the limit value input in N_SC2REF to determine whether the current reaches the charging upper limit; the comparator U4C performs a discharge upper limit overcurrent detection, and the comparator U2C compares the sampled current signal with the limit value input in N_SC1REF to determine whether the current reaches the discharge upper limit; when the comparator U4A detects an overcurrent signal, the output terminal 1 of the comparator U4A outputs a high-level signal, that is, a primary shutdown signal controls the switch tube to be disconnected; at the same time, the high-level signal acts on the resistor R27 of the signal control circuit through the diode D5, and the transistor Q4 is forced to be turned on under the action of the high-level signal, so the NEG_EN signal is grounded after passing through R24, thereby pulling down the NEG_EN signal, that is, the secondary shutdown signal, and again controlling the shutdown of the positive switch tube and the negative switch tube to achieve the overcurrent protection function. Through the independent control of the charging and discharging power switch tubes, a higher level of functional safety is achieved, and the overcurrent state is maintained under the action of the switch tube D6 to achieve the locking function. When the comparator U4C detects an overcurrent signal, the output terminal 8 of the comparator U4C outputs a high-level signal, that is, a primary shutdown signal controls the switch tube to disconnect; at the same time, the high-level signal acts on the resistor R27 of the signal control circuit through the diode D5, and the transistor Q4 is forced to turn on under the action of the high-level signal, so the NEG_EN signal is grounded after R24, and then the NEG_EN signal is pulled down, that is, the secondary shutdown signal, and the positive switch tube and the negative switch tube are controlled to be turned off again to achieve the overcurrent protection function. And the overcurrent state is maintained under the action of the switch tube D8 to achieve the locking function.

[0043] When an overcurrent condition occurs, after the vehicle system is repaired and the fault is eliminated, the system reset circuit inputs a reset signal to NEG_RST to achieve overcurrent protection lock reset of the entire eFuse circuit.

[0044] like Figure 5As shown, the limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input into P_SC2REF and P_SC1REF, and is used by comparator U2A and comparator U2C to determine whether the current exceeds the limit. The overcurrent signal limit value includes two setting methods: controlling the DAC to set the overcurrent signal limit value through the microcontroller module; and setting the overcurrent signal limit value through the IC.

[0045] Embodiment 2

[0046] A vehicle-mounted eFuse control method with functional safety, comprising:

[0047] Step S1, monitoring the current signal of the sampling resistor, inputting it into the signal amplification circuit, and outputting it to the overcurrent detection circuit after being amplified by the operational amplifier;

[0048] Step S2, the limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input to the overcurrent detection circuit to determine whether the current exceeds the limit;

[0049] Step S3, the comparator in the overcurrent detection circuit performs charge and discharge upper limit overcurrent detection. When the comparator detects an overcurrent signal, it generates a primary shutdown signal to control the switch tube to be disconnected; the primary shutdown signal is simultaneously applied to the microcontroller module to generate a secondary shutdown signal, which controls the power switch tube to be turned off again to achieve an overcurrent protection function; at the same time, the comparator is connected in parallel with a diode to achieve overcurrent state locking;

[0050] Step S4, when an overcurrent circuit is detected and the vehicle system is inspected and troubleshooted, the system reset circuit inputs a reset signal to reset the on-board eFuse.

[0051] The embodiments of this specific implementation mode are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be included in the protection scope of the present invention. Although the preferred embodiments of the present invention have been described, once the technical personnel in this field know the basic creative concept, they can make other changes and modifications to these embodiments. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, the technical personnel in this field can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and variations.

Claims

1. A vehicle-mounted eFuse circuit with functional safety, characterized in that: It includes a pre-charge control circuit module, a positive power switch tube circuit module, a negative power switch tube circuit module, a negative PTC heating control circuit module, a drive circuit module, a microcontroller module, a sampling circuit module, a voltage protection module, a current protection module, and a power supply module; the power supply module supplies power to the sampling circuit module, the microcontroller module, and the drive circuit module; the drive circuit module receives a control signal from the microcontroller module and a control signal output from the sampling circuit module, and is used to drive and control the conduction and cutoff of the power switch tubes in each power switch tube module; The positive power switch tube circuit module is composed of a group of positive charging power switch tubes and a group of positive discharging power switch tubes back to back, and the negative power switch tube circuit module is composed of a group of negative charging power switch tubes and a group of negative discharging power switch tubes back to back. The positive discharge power switch tube is connected to the positive electrode of the vehicle-mounted power battery, and the output side of the positive charging power switch tube is used to connect to the positive electrode of the vehicle-mounted high-voltage load. One end of the negative charging power switch tube is connected to the negative electrode of the vehicle-mounted power battery, and one end of the negative discharge power switch tube is used to connect to the negative electrode of the vehicle-mounted high-voltage load.

2. The vehicle-mounted eFuse circuit according to claim 1, characterized in that: The sampling circuit module includes: a positive sampling circuit and a negative sampling circuit.

3. The vehicle-mounted eFuse circuit according to claim 1, characterized in that: The sampling circuit module includes: a signal amplification circuit, an overcurrent detection circuit, a signal control circuit, a system reset circuit, and a limit value preset circuit; The signal amplification circuit is used to amplify the collected current signal and input it into the overcurrent detection circuit; the overcurrent detection circuit receives the voltage signal of the amplified current information of the signal amplification circuit, and determines whether there is an overcurrent according to a preset limit value. If it is in an overcurrent state, a primary shutdown signal is generated, and the primary shutdown signal controls the power switch tube to shut down; the primary shutdown signal acts on the microcontroller module at the same time to generate a secondary shutdown signal, and controls the power switch tube to shut down again; the system reset circuit performs a system reset after an overcurrent; the limit value preset circuit sets the overcurrent state limit value.

4. The vehicle-mounted eFuse circuit as claimed in claim 3, characterized in that: The overcurrent detection circuit includes a detection comparison circuit and an overcurrent locking circuit.

5. The vehicle-mounted eFuse circuit as claimed in claim 4, characterized in that: The detection and comparison circuit includes a window comparator, which performs charging upper limit overcurrent detection and discharging upper limit overcurrent detection respectively.

6. The vehicle-mounted eFuse circuit as claimed in claim 4, characterized in that: The overcurrent locking circuit is a positive feedback circuit structure and includes an ultrafast recovery diode.

7. A method for controlling an on-vehicle eFuse circuit with functional safety, characterized in that: include: Step S1, monitoring the current signal of the sampling resistor, inputting it into the signal amplification circuit, and outputting it to the overcurrent detection circuit after being amplified by the operational amplifier; Step S2, the limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input to the overcurrent detection circuit to determine whether the current exceeds the limit; Step S3, the comparator in the overcurrent detection circuit performs charge and discharge upper limit overcurrent detection. When the comparator detects an overcurrent signal, it generates a primary shutdown signal to control the switch tube to be disconnected; the primary shutdown signal is simultaneously applied to the microcontroller module to generate a secondary shutdown signal, which controls the power switch tube to be turned off again to achieve an overcurrent protection function; at the same time, the comparator is connected in parallel with a diode to achieve overcurrent state locking; Step S4, when an overcurrent circuit is detected and the vehicle system is inspected and troubleshooted, the system reset circuit inputs a reset signal to reset the on-board eFuse.

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