Vehicle-mounted eFuse circuit with functional safety and control method

Abstract

The application discloses a kind of vehicle-mounted eFuse circuit with functional safety and control method, vehicle-mounted eFuse circuit includes pre-charge control circuit module, positive electrode power switch tube circuit module, negative electrode power switch tube circuit module, negative electrode PTC heating control circuit module, drive circuit module, microcontroller module, sampling circuit module, power supply module;The drive circuit module accepts control signal from microcontroller module and accepts control signal output from sampling circuit module, and the conduction and cut-off of power switch tube in each power switch tube module is driven and controlled, the control of switch tube is disconnected or connected to disconnect or connect current path, to respond to abnormal situation occurred in circuit, replace traditional fuse.

Description

TECHNICAL FIELD

[0001] The application relates to an automobile electrical system, in particular to a vehicle-mounted eFuse circuit with functional safety and a control method. BACKGROUND

[0002] The battery, motor and electric control technology of a new energy automobile are core technologies of an electric automobile, with the rise of intelligent driving and domain controllers, the safety, reliability and intelligent degree of the electrical system are required to be improved, and the diagnosis requirement of the electrical circuit is higher and higher. The new energy automobile industry is experiencing a change from traditional hardware orientation to software defined vehicle, and the traditional fuse cannot meet these requirements.

[0003] An eFuse (electronic fuse) is an integrated protection circuit used to limit the circuit current and voltage at a safe level in the event of a fault. The eFuse, as a more advanced circuit protection device, emerges in the new energy automobile electric control system. Compared with the traditional fuse, the eFuse has many advantages, such as long service life, fast reaction speed, self-recovery, small size, rich functions, low maintenance cost and the like. Therefore, the eFuse plays an important role in automatic driving iteration, low-voltage system upgrade and E / E architecture improvement. At present, the eFuse with compact layout is used in new energy automobiles to replace traditional fuses and relays, thereby providing more accurate protection for the electric control system of the new energy automobile, realizing programmable and diagnosable power supply, and also providing support for the intelligentization and high efficiency of the automobile electrical system. SUMMARY

[0004] The application provides a vehicle-mounted eFuse circuit with functional safety and a control method, which replaces the traditional fuse by controlling the on-off of the switch tube to disconnect or connect the current path in response to abnormal conditions occurring in the circuit, and realizes efficient, accurate, safe and intelligent control of the automobile electrical system.

[0005] The application provides a vehicle-mounted eFuse circuit with functional safety, which comprises 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 driving 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 driving circuit module. The driving circuit module receives control signals from the microcontroller module and control signals output from the sampling circuit module, and is used for driving and controlling the conduction and cutoff of the power switch tube in each power switch tube module.

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

[0007] Preferably, the sampling circuit module comprises a positive electrode sampling circuit and a negative electrode sampling circuit.

[0008] Preferably, the sampling circuit module comprises 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 for amplifying the collected current signal and inputting the current signal to the overcurrent detection circuit; the overcurrent detection circuit receives the voltage signal of the amplified current information of the signal amplification circuit, judges whether overcurrent occurs according to the preset limit value, generates a first shutdown signal to control the switch tube to be disconnected when the comparator detects the overcurrent signal, the first shutdown signal acts on the microcontroller module at the same time to generate a second shutdown signal, and the power switch tube is controlled to be disconnected again to realize the overcurrent protection function; the system reset circuit performs system reset after overcurrent; and the limit value preset circuit sets the overcurrent state limit value.

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

[0011] Preferably, the detection comparison circuit comprises 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 and comprises an ultrafast recovery diode.

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

[0014] In step S1, the current signal of the sampling resistor is monitored and input to the signal amplification circuit, and then output to the overcurrent detection circuit after being amplified by the operational amplifier;

[0015] In 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 judge whether the current is over limit;

[0016] Step S3, the comparator in the overcurrent detection circuit carries out the upper limit overcurrent detection of charging and discharging, when the comparator detects the overcurrent signal, generates a primary shutdown signal to control the switch tube to be turned off; the primary shutdown signal acts on the microcontroller module at the same time, generates a secondary shutdown signal, controls the power switch tube to be turned off again, and realizes the overcurrent protection function; at the same time, the overcurrent state locking is realized through the comparator and the parallel diode.

[0017] Step S4, when the overcurrent circuit is detected, after the vehicle system completes the maintenance and fault elimination, the system reset circuit inputs a reset signal to make the vehicle eFuse reset.

[0018] The technical scheme provided in the embodiment of the application has the following technical effects:

[0019] 1. The application adopts the positive and negative power switch tube circuit module to replace the traditional fuse, and realizes the control of the on-off of the switch tube to disconnect or connect the current path in response to the abnormal situation occurring in the circuit through the overcurrent detection circuit and the twice overcurrent control of the microcontroller module. The pre-charging circuit module is set, and the pre-charging circuit is added in the charging and discharging process of the switch tube, so as to ensure the slow establishment of the bus, prevent the impact of large starting current, and ensure the safety of the load.

[0020] 2. The comparator and the diode are set in the sampling circuit module, the overcurrent judgment and overcurrent state locking can be completed, the whole system is more safe and efficient, the overcurrent state limiting value in the application can be set autonomously through the limiting value preset circuit according to actual needs, different vehicles and different states can be universalized by using the system, and the system reset circuit is further set in the application, so that the one-key overcurrent locking reset can be realized after maintenance, and the operation is more simple and convenient. DETAILED DESCRIPTION

[0021] Figure 1 It is a system diagram of the vehicle eFuse circuit of the application;

[0022] Figure 2 It is a system diagram of the current sampling module of the application;

[0023] Figure 3 It is a positive electrode charging and discharging monitoring circuit diagram of the application;

[0024] Figure 4 It is a negative electrode charging and discharging monitoring circuit diagram of the application;

[0025] Figure 5 It is an overcurrent signal limiting value setting circuit diagram of the application;

[0026] Figure 6 It is a vehicle eFuse control method flow chart of the application. DETAILED DESCRIPTION

[0027] This application provides a functionally safe vehicle-mounted eFuse circuit and control method to replace traditional mechanical fuses. It independently implements pre-charge control, charging control, and discharging control for the positive and negative terminals of the automotive high-voltage battery, and achieves ASIL D safety level through the design of redundant sampling and protection circuits.

[0028] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0029] Example 1

[0030] like Figure 1 As shown, the on-board eFuse circuit includes a pre-charge control circuit module, a positive power switch circuit module, a negative power switch circuit module, a negative PTC heating control circuit module, a switch driver 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 driver circuit module, the voltage protection module, and the current protection module. The switch driver circuit module receives control signals from the microcontroller module and drives the power switches in each power switch module to turn on and off.

[0031] The positive power switch circuit module consists of a set of positive charging power switches and a set of positive discharging power switches back-to-back. The negative power switch circuit module consists of a set of negative charging power switches and a set of negative discharging power switches back-to-back. Positive discharging power switches Q1 and Q2 are connected to the positive terminal of the vehicle's power battery. The output sides of positive charging power switches Q3 and Q4 are used to connect to the positive terminal of the vehicle's high-voltage load. Negative charging power switches Q6 and Q7 are connected to the negative terminal of the vehicle's power battery. Negative discharging power switches Q8 and Q9 are connected to the negative terminal of the vehicle's high-voltage load. Gate driver 1 drives positive discharging power switches Q1 and Q2 to turn them on and off. Gate driver 2 drives positive charging power switches Q3 and Q4 to turn them on and off. Gate driver 4 drives negative charging power switches Q6 and Q7 to turn them on and off. The gate driver 5 drives the negative discharge power switches Q8 and Q9 to turn the negative discharge switches on and off.

[0032] The pre-charging control circuit module includes a pre-charging resistor and a pre-charging power switch Q3, one end of the pre-charging resistor is connected with the positive electrode of the vehicle-mounted power battery, the other end is connected with the pre-charging power switch Q3, and the other end of the pre-charging power switch is connected with the output side of the positive electrode discharging power switch. The pre-charging switch Q3 is driven and controlled by the gate drive 3 to realize switching action, realizing the pre-charging function, and the pre-charging resistor is used for limiting the pre-charging current. When a gate drive fault occurs, the fault signal output by the gate drive 3 is sent to the controller.

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

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

[0035] The power supply module can independently supply power to the gate drive. Since the self-restoring fuse is present, the damage of all power supplies does not affect other branch power supplies, thereby enhancing the reliability of the system.

[0036] As shown in Figure 2 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] As shown in Figure 3 The current sampling module 1 monitors the current signal POS_IS+ of the positive electrode sampling resistor, the current signal POS_IS+ is input to the signal amplification circuit of the microcontroller module, and the current signal POS_IS+ represents the current flowing through the positive electrode sampling resistor. The differential signal is amplified by the operational amplifier U2B and input to the overcurrent detection circuit.

[0038] The signal recognition circuit includes operational comparator U2A, comparator U2C, diode D1, diode D2, diode D3, diode D4; the comparator U2A performs charging upper limit overcurrent detection, the comparator U2A compares the sampling current signal with the limit value input in P_SC2REF, and judges whether the current reaches the charging upper limit; the comparator U2C performs discharging upper limit overcurrent detection, the comparator U2C compares the sampling current signal with the limit value input in P_SC1REF, and judges whether the current reaches the discharging upper limit; when the comparator U2A detects the overcurrent signal, the output end 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 the overcurrent signal, the high level signal acts on the resistor R4 of the signal control circuit through the diode D1, and under the action of the high level signal, the triode Q1 is forced to conduct, so that the POS_EN signal is grounded after R2, and then the POS_EN signal is pulled low, that is, a secondary shutdown signal, which controls the positive and negative switch tubes to be disconnected 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 realized, and under the action of the switch tube D2, the overcurrent state is maintained to realize the locking function. When the comparator U2C detects the overcurrent signal, the output end 8 of the comparator U2C 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 U2C detects the overcurrent signal, the high level signal acts on the resistor R4 of the signal control circuit through the diode D3, and under the action of the high level signal, the triode Q1 is forced to conduct, so that the POS_EN signal is grounded after R2, and then the POS_EN signal is pulled low, that is, a secondary shutdown signal, which controls the positive and negative switch tubes to be disconnected again to realize the overcurrent protection function. And under the action of the switch tube D4, the overcurrent state is maintained to realize the locking function.

[0039] When the overcurrent condition occurs, after the vehicle system completes the repair and fault elimination, the system reset circuit inputs a reset signal to POS_RST to realize the overcurrent protection locking reset of the entire eFuse circuit.

[0040] As shown in Figure 5 The limit value preset circuit sets the overcurrent signal limit value, and the set limit value is input into N_SC2REF and N_SC1REF for the comparator U4A and the comparator U4C to judge whether the current is over limit.

[0041] As shown in Figure 4As shown, the current sampling module 2 monitors the current signal NEG_IS+ of the negative electrode sampling resistor, the current signal NEG_IS+ is input to the signal amplification circuit of the microcontroller module, and 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 the operational comparator U4A, the comparator U4C, the diode D5, the diode D6, the diode D7, and the diode D8; the comparator U4A performs charging upper limit overcurrent detection, the comparator U2A compares the sampling current signal with the limit value input in N_SC2REF to determine whether the current reaches the charging upper limit; the comparator U4C performs discharging upper limit overcurrent detection, the comparator U2C compares the sampling current signal with the limit value input in N_SC1REF to determine whether the current reaches the discharging upper limit; when the comparator U4A detects the overcurrent signal, the output end 1 of the comparator U4A outputs a high-level signal, i.e., a primary shutdown signal to control 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 under the action of the high-level signal, the triode Q4 is forced to be turned on, so that the NEG_EN signal is grounded after passing through R24, thereby pulling down the NEG_EN signal, i.e., a secondary shutdown signal, to control the positive electrode switch tube and the negative electrode switch tube to be disconnected 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 realized, and the overcurrent state is maintained under the action of the switch tube D8 to realize the locking function. When the comparator U4C detects the overcurrent signal, the output end 8 of the comparator U4C outputs a high-level signal, i.e., a primary shutdown signal to control 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 under the action of the high-level signal, the triode Q4 is forced to be turned on, so that the NEG_EN signal is grounded after passing through R24, thereby pulling down the NEG_EN signal, i.e., a secondary shutdown signal, to control the positive electrode switch tube and the negative electrode switch tube to be disconnected again to realize the overcurrent protection function. And the overcurrent state is maintained under the action of the switch tube D8 to realize the locking function.

[0043] When the overcurrent condition occurs, after the vehicle system completes the maintenance and fault elimination, the system reset circuit inputs a reset signal to NEG_RST to realize the overcurrent protection locking reset of the entire eFuse circuit.

[0044] As 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 for the comparator U2A and the comparator U2C to judge whether the current is over limit. The overcurrent signal limit value includes two setting methods: the overcurrent signal limit value is set by the microcontroller module controlling the DAC; and the overcurrent signal limit value is set by the IC.

[0045] Embodiment two

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

[0047] Step S1, monitoring the current signal of the sampling resistor, inputting into the signal amplification circuit, and outputting 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 into the overcurrent detection circuit for judging whether the current is over limit;

[0049] Step S3, the comparator in the overcurrent detection circuit performs the upper limit overcurrent detection, and when the comparator detects the overcurrent signal, generates a primary shutdown signal to control the switch tube to be turned off; the primary shutdown signal simultaneously acts on the microcontroller module to generate a secondary shutdown signal, and controls the power switch tube to be turned off again to realize the overcurrent protection function; and the overcurrent state is locked through the comparator and the parallel diode;

[0050] Step S4, when the overcurrent circuit is detected, the system reset circuit inputs the reset signal to make the vehicle-mounted eFuse reset after the vehicle system completes the maintenance and fault elimination.

[0051] The embodiments of the specific implementation are the preferred embodiments of the present application, not limited to the protection scope of the present application, so that: any equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application. Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to the embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application. Obviously, those skilled in the art can make various modifications and changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and changes of the present application fall within the scope of the claims of the present application and their equivalents, the present application also intends to include these modifications and changes.

Claims

1. An in-vehicle eFuse circuit with functional safety, characterized by, The application relates to a power management circuit for a vehicle-mounted power battery, which comprises 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 driving 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 driving circuit module; the driving circuit module receives control signals from the microcontroller module and control signals output from the sampling circuit module, and is used for driving and controlling the conduction and cutoff of power switch tubes in the power switch tube modules; 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 in back-to-back mode, 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 in back-to-back mode; the positive discharging power switch tube is connected to the positive pole of the vehicle-mounted power battery, the output side of the positive charging power switch tube is used for connecting the positive pole of the vehicle-mounted high-voltage load, one end of the negative charging power switch tube is connected to the negative pole of the vehicle-mounted power battery, and one end of the negative discharging power switch tube is used for connecting the negative pole of the vehicle-mounted high-voltage load.

2. The in-vehicle eFuse circuit of claim 1, wherein, The sampling circuit module comprises positive sampling circuits and negative sampling circuits.

3. The in-vehicle eFuse circuit of claim 1, wherein, The sampling circuit module comprises a signal amplification circuit, an overcurrent detection circuit, a signal control circuit, a system reset circuit and a limited value preset circuit. The signal amplification circuit is used for amplifying the collected current signals and inputting the current signals into the overcurrent detection circuit; the overcurrent detection circuit receives the voltage signals of the amplified current information of the signal amplification circuit, judges whether overcurrent exists according to the preset limited value, generates a primary cutoff signal if overcurrent exists, and the primary cutoff signal controls the cutoff of the power switch tube; the primary cutoff signal simultaneously acts on the microcontroller module to generate a secondary cutoff signal, and the secondary cutoff signal controls the cutoff of the power switch tube again; the system reset circuit resets the system after overcurrent; and the limited value preset circuit sets the limited value of the overcurrent state.

4. The in-vehicle eFuse circuit of claim 3, wherein, The overcurrent detection circuit comprises a detection comparison circuit and an overcurrent locking circuit.

5. The in-vehicle eFuse circuit of claim 4, wherein, The detection comparison circuit comprises window comparators and is used for performing charging upper-limit overcurrent detection and discharging upper-limit overcurrent detection.

6. The in-vehicle eFuse circuit of claim 4, wherein, The overcurrent locking circuit is a positive feedback circuit structure and comprises an ultrafast recovery diode.

7. A method of controlling a functionally safe in-vehicle eFuse circuit, for controlling the functionally safe in-vehicle eFuse circuit according to claim 1, characterized by, The application further discloses a power management method for a vehicle-mounted power battery, which comprises the following steps: S1, monitoring the current signals of sampling resistors, inputting the current signals into a signal amplification circuit, amplifying the current signals through an operational amplifier and outputting the current signals into an overcurrent detection circuit; S2, setting the limited value of overcurrent signals through a limited value preset circuit, inputting the set limited value into the overcurrent detection circuit, and judging whether the current is overlimited; S3, performing charging upper-limit overcurrent detection and discharging upper-limit overcurrent detection through comparators in the overcurrent detection circuit, generating a primary cutoff signal to control the cutoff of a switch tube when the comparators detect overcurrent signals, simultaneously acting on a microcontroller module to generate a secondary cutoff signal, controlling the cutoff of the power switch tube again, realizing the overcurrent protection function, and realizing overcurrent state locking through comparators and parallel diodes. Step S4, when detecting the overcurrent circuit, the vehicle system completes the maintenance and troubleshooting, and the system reset circuit inputs the reset signal to make the vehicle eFuse reset.

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