Circuit for diagnosing whether supply voltage of passenger car is in safety interval

Abstract

The utility model discloses a circuit for diagnosing that the supply voltage of a passenger car is in a safe interval. The device comprises a safety voltage range setting part and a logic gate fault output part, a vehicle-mounted power supply is connected with an MCU micro-control unit through the safety voltage range setting part and the logic gate fault output part in sequence, and the safety voltage range setting part and the logic gate fault output part are both connected with a logic power supply. The safety voltage range setting part comprises a plurality of resistors, comparators and comparators, and the logic gate fault output part comprises a chip and a plurality of resistors. According to the utility model, the normal operation of the vehicle-mounted controller is ensured by monitoring whether the power supply voltage of the passenger vehicle controller is within the safety interval, and the function safety level of the vehicle-mounted controller in use is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile electronic circuits, in particular to a circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range. Background Art

[0002] Passenger car systems are usually 12V systems, and the safe range voltage of their controllers is designed to be 9V to 16V. Within this range, there is no damage to the on-board controller, and all its functions and performance are normal. When the controller power supply voltage is lower than 9V, the low voltage causes some functions of the controller to not guarantee normal performance, and there is also the problem of over-discharge of the on-board battery, resulting in reduced battery life and damage. When the on-board controller power supply voltage is greater than 16V, long-term high-voltage operation will cause the controller to generate excessive heat, thereby reducing the life of the controller. Utility Model Content

[0003] In order to solve the problems existing in the background technology, the utility model proposes a circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range, which solves the technical problem that the power supply voltage of a passenger car in the prior art cannot be quickly and accurately judged within the safe range under limited cost.

[0004] The technical solution of the utility model is achieved in this way:

[0005] The utility model comprises two parts, a safety voltage range setting part and a logic gate fault output part. The vehicle power supply VBAT_SUP is connected to the MCU micro-control unit in sequence via the safety voltage range setting part, the logic gate fault output part, and the safety voltage range setting part and the logic gate fault output part are both connected to the logic power supply.

[0006] The safety voltage range setting part includes multiple resistors, comparator U3 and comparator U4. The positive phase input terminal of comparator U3 is connected to the vehicle power supply VBAT_SUP via resistor R7, and the positive phase input terminal of comparator U3 is connected to the positive phase input terminal of comparator U4 via resistor R9, resistor R12 and comparator U4 in sequence. The positive phase input terminal of comparator U4 is connected to the ground via resistor R7; the inverting input terminal of comparator U3 is connected to the logic power supply via resistor R10, and is also connected to the ground via resistor R11; the inverting input terminal of comparator U4 is connected to the logic power supply via resistor R15, and is also connected to the ground via resistor R16; the output terminals of comparator U3 and comparator U4 are respectively connected to the logic gate fault output part.

[0007] The logic gate fault output part includes a chip IC1 and multiple resistors. The INB pin of the chip IC1 is grounded through a resistor R8 and connected to the output end of the comparator U3; the INA pin of the chip IC1 is grounded through a resistor R13 and connected to the output end of the comparator U4; the VCC pin of the chip IC1 is connected to the logic power supply and grounded through a capacitor C4; the GND pin of the chip IC1 is grounded, and the OUT pin is connected to the general output port FAULIT_OUT of the MCU micro-control unit.

[0008] Beneficial effects of the utility model:

[0009] The utility model monitors whether the power supply voltage of the passenger car controller is within the safe range, thereby ensuring the normal operation of the vehicle controller. This circuit design improves the functional safety level of the vehicle controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The invention is a circuit schematic diagram for diagnosing that the power supply voltage is within the normal operating range. DETAILED DESCRIPTION

[0011] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0012] like Figure 1 As shown, the specific implementation includes two parts: an MCU micro-control unit, a safe voltage range setting part and a logic gate fault output part. The vehicle power supply VBAT_SUP is connected to the MCU micro-control unit in sequence through the safe voltage range setting part, the logic gate fault output part and the MCU micro-control unit, and the safe voltage range setting part and the logic gate fault output part are both connected to the logic power supply 5V.

[0013] The safety voltage range setting part includes multiple resistors, comparator U3 and comparator U4. The No. 3 positive input terminal of comparator U3 is connected to the vehicle power supply VBAT_SUP through resistor R7. The No. 3 positive input terminal of comparator U3 is connected to the No. 3 positive input terminal of comparator U4 through resistor R9, resistor R12 and the No. 3 positive input terminal of comparator U4 in turn. The No. 3 positive input terminal of comparator U4 is connected to the ground through resistor R7; the No. 2 inverting input terminal of comparator U3 is connected to the logic power supply 5V through resistor R10, and is also grounded through resistor R11; the No. 2 inverting input terminal of comparator U4 is connected to the logic power supply 5V through resistor R15, and is also grounded through resistor R16; the output terminals of comparator U3 and comparator U4 are respectively connected to the INB pin and INA pin of the chip IC1 of the logic gate fault output part; in addition, the No. 7 pin V+ of comparator U3 is connected to 5V and the No. 2 pin of capacitor C3. The No. 1 pin of capacitor C3 is grounded, and the No. 4 pin V- of comparator U3 is grounded. The No. 7 V+ pin of the comparator U4 and the No. 2 pin of the capacitor C5 are both connected to 5 V. The No. 1 pin of the capacitor C5 is grounded, and the No. 4 V- pin of the comparator U4 is grounded.

[0014] The logic gate fault output part includes chip IC1 and multiple resistors. The No. 1 INB pin of chip IC1 is grounded through resistor R8 and connected to the output end of comparator U3; the No. 1 INA pin of chip IC1 is grounded through resistor R13 and connected to the output end of comparator U4; the No. 5 VCC pin of chip IC1 is connected to the logic power supply 5V and grounded through capacitor C4; the No. 3 GND pin of chip IC1 is grounded, and the No. 4 OUT pin is connected to the general output port FAULIT_OUT of the MCU micro-control unit.

[0015] In the specific implementation, the comparators U3 and U4 are LM2903, the IC1 is SN74AHC1G86DBVR, which is a two-signal input XOR gate chip, the resistance of resistor R7 is 300K, the resistance of resistor R9 is 10K, the resistance of resistor R12 is 10K, the resistance of resistor R14 is 40K, the resistance of resistor R16 is 2.5K, the resistance of resistor R15 is 10K, the resistance of resistor R10 is 10K, and the resistance of resistor R11 is 11.4K. The resistance of resistor R8 is 10K, and the resistance of resistor R13 is 10K. The capacitance of capacitors C3 and C5 is 100nF.

[0016] By setting the resistance values ​​of resistors R7, R9, R10-R12, R14-R16, when the voltage of the vehicle power supply VBAT_SUP is the highest voltage in the safety interval, the voltage of the non-inverting input terminal of the comparator U3 is the same as the voltage of the inverting input terminal; and when the voltage of the vehicle power supply VBAT_SUP is the lowest voltage in the safety interval, the voltage of the non-inverting input terminal of the comparator U4 is the same as the voltage of the inverting input terminal;

[0017] Then, the chip IC1 monitors the output of the OUT output terminals of the comparator U3 and the comparator U4 in real time, performs logical XOR processing to output the final high and low level results, and determines whether the vehicle power supply VBAT_SUP voltage is within the safe range based on the final high and low level results.

[0018] When the OUT output terminals 6 of the comparator U3 and the comparator U4 are both low or high, the chip IC1 detects that the output is low and the vehicle power supply VBAT_SUP voltage is not within the safe range;

[0019] When one of the OUT output terminals 6 of the comparator U3 and the comparator U4 is at a high level and the other is at a low level, the chip IC1 detects that the output is at a high level, and the vehicle power supply VBAT_SUP voltage is within the safe range.

[0020] By performing detection and diagnosis in the above manner, and then using voltage control means to control the voltage of the vehicle power supply VBAT_SUP, the vehicle power supply VBAT_SUP can be kept within a safe range.

[0021] The embodiments of the present utility model and their implementation process are as follows:

[0022] Usually, the normal power supply voltage range of the vehicle controller is VBAT_SUP 9V-16V, and the logic power supply is 5V. The following example takes VBAT_SUP as 9V and 16V respectively:

[0023] 1. When the voltage of the vehicle power supply VBAT_SUP is 16V, the voltage of the non-inverting input terminal of the comparator U3 is:

[0024] VBAT_SUP*(R9+R12+R14) / (R7+R9+R12+R14)=16V*(10K+10K+40K) / (300K+10K+10K+40K)=2.66V

[0025] Among them, VBAT_SUP represents the voltage of the vehicle power supply VBAT_SUP.

[0026] The voltage at the inverting input of comparator U3 is:

[0027] 5V*R11 / (R11+R10)=5V*11.4K / (11.4K+10K)=2.66V

[0028] Therefore, when the voltage of the vehicle power supply VBAT_SUP is less than or equal to 16V, the positive input terminal of the comparator U3 is less than or equal to 2.66V, and the negative input terminal of the comparator U3 is constantly equal to 2.66V. Therefore, the negative input terminal voltage of the comparator U3 is greater than the positive input terminal voltage of the comparator U3, so the OUT output terminal of the comparator U3 is low level (0V);

[0029] When the voltage of the vehicle power supply VBAT_SUP is greater than 16V, the positive input terminal of the comparator U3 is greater than 2.66V, and the negative input terminal of the comparator U3 is constantly equal to 2.66V. Therefore, the positive input terminal voltage of the comparator U3 is greater than the negative input terminal voltage of the comparator U3, and the OUT output terminal of the comparator U3 is high level.

[0030] 2. When the voltage of the vehicle power supply VBAT_SUP is 16V, the voltage of the non-inverting input terminal of the comparator U4 is:

[0031] VBAT_SUP*R14 / (R7+R9+R12+R14)=16V*(40K) / (300K+10K+10K+40K)=1.77V

[0032] The voltage at the inverting input of comparator U4 is:

[0033] 5V*R16 / (R15+R16)=5V*2.5K / (10K+2.5K)=1V

[0034] When the voltage of the vehicle power supply VBAT_SUP is greater than 16V, the positive input terminal of the comparator U4 is greater than 1.77V, and the inverting input terminal of the comparator U4 is constantly equal to 1V. Therefore, the voltage of the positive input terminal of the comparator U4 is greater than the voltage of the inverting input terminal of the comparator U4, and the OUT output terminal 6 of the comparator U4 is high.

[0035] 3. When the voltage of the vehicle power supply VBAT_SUP is 9V, the voltage of the non-inverting input terminal of the comparator U3 is:

[0036] VBAT_SUP*(R9+R12+R14) / (R7+R9+R12+R14)=9V*(10K+10K+40K) / (300K+10K+10K+40K)=1.5V

[0037] The voltage at the inverting input of comparator U3 is:

[0038] 5V*R11 / (R11+R10)=5*11.4K / (10K+11.4K)=2.66V

[0039] When the voltage of the vehicle power supply VBAT_SUP is less than 9V, the positive input terminal of the comparator U3 is less than 1.5V, and the negative input terminal of the comparator U3 is constantly equal to 2.66V. Therefore, the positive input terminal voltage of the comparator U3 is less than the negative input terminal voltage of the comparator U3, and the OUT output terminal 6 of the comparator U3 is low level (0V).

[0040] 4. When the voltage of the vehicle power supply VBAT_SUP is 9V, the voltage of the non-inverting input terminal of the comparator U4 is:

[0041] VBAT_SUP*R14 / (R7+R9+R12+R14)=9V*(40K) / (300K+10K+10K+40K)=1V

[0042] The voltage at the inverting input of comparator U4 is:

[0043] 5V*R16 / (R15+R16)=5*2.5K / (10K+2.5K)=1V

[0044] When the voltage of the vehicle power supply VBAT_SUP is less than 9V, the positive input terminal of the comparator U4 is less than 1V, and the negative input terminal of the comparator U4 is constantly equal to 1V. Therefore, the positive input terminal voltage of the comparator U4 is less than the negative input terminal voltage of the comparator U4, and the OUT output terminal 6 of the comparator U4 is low level (0V).

[0045] When the voltage of the vehicle power supply VBAT_SUP is greater than or equal to 9V, the positive input terminal of the comparator U4 is greater than or equal to 1V, and the inverting input terminal of the comparator U4 is constantly equal to 1V. Therefore, the voltage of the positive input terminal of the comparator U4 is greater than or equal to the voltage of the inverting input terminal of the comparator U4, and the OUT output terminal 6 of the comparator U4 is high level.

[0046] Therefore, combined with the above situation, it can be seen that when the voltage of the vehicle power supply VBAT_SUP is less than 9V, the OUT output terminals 6 of the comparator U3 and the comparator U4 are both low level;

[0047] When the voltage of the vehicle power supply VBAT_SUP is greater than or equal to 9V and less than or equal to 16V, the OUT output terminal 6 of the comparator U3 is at a low level, and the OUT output terminal 6 of the comparator U4 is at a high level;

[0048] When the voltage of the vehicle power supply VBAT_SUP is greater than 16V, the OUT output terminals 6 of the comparator U3 and the comparator U4 are both at a high level.

[0049] The specific input logic truth table is as follows

[0050] VBAT_SUP U3-OUT U4-OUT Logical XOR (FaultOUT) output <9V 0 0 0 9<＝X<＝16 0 1 1 >16 1 1 0

[0051] Then, according to the real-time monitoring of the output of the OUT output of comparator U3 and comparator U4 by chip IC1, a logical XOR processing is performed to output the final high and low level results. When the chip IC1 detects that the output is only high level, the vehicle power supply VBAT_SUP is used as the power supply voltage, and its voltage is within the safe range; when the chip IC1 detects that the output is low level, the vehicle power supply VBAT_SUP voltage is not within the safe range.

[0052] Finally, the voltage of the vehicle power supply VBAT_SUP can be controlled by using voltage control means to ensure that the vehicle power supply VBAT_SUP is maintained between 9V and 16V.

[0053] As can be seen from the above table, the utility model can accurately, quickly and efficiently detect whether the power supply voltage of a passenger car is within a safe range by making a judgment according to the logic of the above table and the circuit of the utility model.

[0054] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range, characterized in that: It includes two parts: a safety voltage range setting part and a logic gate fault output part. The on-board power supply VBAT_SUP is connected to the MCU microcontroller unit in sequence through the safety voltage range setting part, the logic gate fault output part, and the safety voltage range setting part and the logic gate fault output part are both connected to the logic power supply.

2. A circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range according to claim 1, characterized in that: The safety voltage range setting part includes multiple resistors, comparator U3 and comparator U4, the non-phase input end of comparator U3 is connected to the vehicle power supply VBAT_SUP via resistor R7, the non-phase input end of comparator U3 is connected to the non-phase input end of comparator U4 via resistor R9, resistor R12 and the non-phase input end of comparator U4 in sequence, and the non-phase input end of comparator U4 is connected to the ground via resistor R7; the output ends of comparator U3 and comparator U4 are respectively connected to the logic gate fault output part.

3. A circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range according to claim 2, characterized in that: The inverting input terminal of the comparator U3 is connected to the logic power supply via the resistor R10 and is also grounded via the resistor R11.

4. A circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range according to claim 2, characterized in that: The inverting input terminal of the comparator U4 is connected to the logic power supply via the resistor R15 and is also grounded via the resistor R16.

5. A circuit for diagnosing whether the power supply voltage of a passenger car is within a safe range according to claim 2, characterized in that: The logic gate fault output part includes a chip IC1 and multiple resistors. The INB pin of the chip IC1 is grounded through a resistor R8 and connected to the output end of the comparator U3; the INA pin of the chip IC1 is grounded through a resistor R13 and connected to the output end of the comparator U4; the VCC pin of the chip IC1 is connected to the logic power supply and grounded through a capacitor C4; the GND pin of the chip IC1 is grounded, and the OUT pin is connected to the general output port FAULIT_OUT of the MCU micro-control unit.

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