CN111817257A - Low-voltage power supply power-down protection circuit and low-voltage power supply power-down protection device - Google Patents
Low-voltage power supply power-down protection circuit and low-voltage power supply power-down protection device Download PDFInfo
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- CN111817257A CN111817257A CN202010741597.0A CN202010741597A CN111817257A CN 111817257 A CN111817257 A CN 111817257A CN 202010741597 A CN202010741597 A CN 202010741597A CN 111817257 A CN111817257 A CN 111817257A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
- B60L3/04—Cutting off the power supply under fault conditions
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Abstract
The invention provides a low-voltage power supply power-down protection circuit and a low-voltage power supply power-down protection device, wherein the low-voltage power supply power-down protection circuit comprises a first power supply input end communicated with a first low-voltage power supply, a second power supply input end communicated with a second low-voltage power supply, a comparison switch circuit and an execution circuit; the first comparison end of the comparison switch circuit is connected with the first power input end, the second comparison end of the comparison switch circuit is connected with the second power input end, the power input end of the comparison switch circuit is communicated with the first low-voltage power supply, and the power output end of the comparison switch circuit is connected with the power end of the execution circuit. The technical scheme of the invention can solve the technical problem that the insulated gate bipolar transistor is damaged due to the fact that the electric drive system executes active short-circuit operation when the low-voltage power supply is powered down.
Description
Technical Field
The invention relates to the technical field of electric automobiles, in particular to a low-voltage power supply power-down protection circuit and a low-voltage power supply power-down protection device.
Background
With the popularization of electric vehicles, the safety of electric vehicles is receiving more and more attention. Specifically, when a safety failure occurs in the electric drive system, for example, a failure that violates torque safety occurs, the electric drive system should enter a safe state, i.e., ASC (active short circuit) or Freewheeling. The path of the electric drive system into the safe state is generally divided into three levels: torque Control hierarchy (software domain), torque monitoring hierarchy (software domain), mcu (micro Control unit) monitoring hierarchy (hardware domain). The MCU monitoring level is completely triggered by hardware and is not controlled by software, so that ASC operation can still be executed under the condition that the MCU fails.
In operation of an electric drive system, once a low-voltage power supply is powered down, the ASC is triggered and executed through the MCU monitoring level, at the moment, because the low-voltage power supply is powered down, the output voltage of the drive power supply drops, so that the drive voltage is insufficient, the IGBT (Insulated Gate Bipolar Transistor) is damaged when the ASC operation is executed under the condition that the drive voltage is insufficient, the IGBT is damaged when the ASC operation is executed in order to prevent the electric drive system from being damaged under the condition, the drive power supply is always backed up, and an extra drive power supply is adopted to take electricity from a high-voltage power battery. However, increasing the backup power supply results in increased cost and PCB area for the electric drive system.
Disclosure of Invention
The invention provides a low-voltage power supply power-down protection circuit and a low-voltage power supply power-down protection device, and aims to solve the technical problem that an insulated gate bipolar transistor is damaged due to the fact that an electric drive system executes active short-circuit operation when a low-voltage power supply is powered down.
In order to achieve the purpose, the invention provides a low-voltage power supply power-down protection circuit, which comprises a first power supply input end communicated with a first low-voltage power supply, a second power supply input end communicated with a second low-voltage power supply, a comparison switch circuit and an execution circuit, wherein the first power supply input end is connected with a first power supply;
a first comparison end of the comparison switch circuit is connected with the first power supply input end, a second comparison end of the comparison switch circuit is connected with the second power supply input end, the power supply input end of the comparison switch circuit is communicated with the first low-voltage power supply, and the power supply output end of the comparison switch circuit is connected with the power supply end of the execution circuit;
and the comparison switch circuit is used for disconnecting the input power supply of the execution circuit according to a preset mode when the second low-voltage power supply is powered off so as to stop the execution circuit from executing the active short-circuit operation.
Optionally, a power input terminal of the comparison switch circuit is connected to the first power input terminal.
Optionally, the comparison switch circuit comprises a comparison circuit and a switch circuit;
the positive input end of the comparison circuit is a first comparison end of the comparison switch circuit, the negative input end of the comparison circuit is a second comparison end of the comparison switch circuit, and the output end of the comparison circuit is connected with the controlled end of the switch circuit;
the power supply input end of the switch circuit is the power supply input end of the comparison switch circuit, and the power supply output end of the switch circuit is the power supply output end of the comparison switch circuit.
Optionally, the switching circuit comprises a first resistor, a second resistor and a first transistor;
a first end of the first resistor is connected with the first power supply input end, a second end of the first resistor is connected with a first end of the second resistor, the first end of the second resistor is a controlled end of the switch circuit, and the second end of the second resistor is connected with a controlled end of the first transistor;
the input end of the first transistor is the power supply input end of the switch circuit, and the output end of the first transistor is the power supply output end of the switch circuit.
Optionally, the power-down protection circuit for the low-voltage power supply further includes a signal detection circuit and an execution signal input terminal;
the input end of the signal detection circuit is connected with the execution signal input end, and the output end of the signal detection circuit is connected with the signal input end of the execution circuit.
Optionally, the signal detection circuit includes a third power input terminal, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a second capacitor, and a second transistor;
a first end of the third resistor is an input end of the signal detection circuit, a second end of the third resistor is connected with a controlled end of the second transistor, a second end of the third resistor is connected with a first end of the fourth resistor, and a second end of the third resistor is connected with a first end of the first capacitor; a second end of the fourth resistor, an output end of the second transistor and a second end of the first capacitor are grounded;
a first end of the fifth resistor is connected with the third power supply input end, a second end of the fifth resistor is an output end of the signal detection circuit, and a second end of the fifth resistor is connected with an input end of the second transistor;
and the second end of the fifth resistor is connected with the first end of the second capacitor, and the second end of the second capacitor is grounded.
Optionally, the execution circuit comprises a digital isolator and an active short execution circuit;
the power supply end of the digital isolator is the power supply end of the execution circuit, the signal input end of the digital isolator is the signal input end of the execution circuit, and the signal output end of the digital isolator is connected with the input end of the active short circuit execution circuit.
Optionally, the low-voltage power supply power-down protection circuit further comprises a voltage stabilizing circuit;
the input end of the voltage stabilizing circuit is connected with the first low-voltage power supply, and the output end of the voltage stabilizing circuit is connected with the input end of the first power supply.
Optionally, the voltage stabilizing circuit comprises a sixth resistor, a zener diode and a third capacitor;
a first end of the sixth resistor is connected with the first low-voltage power supply, a second end of the sixth resistor is connected with the first power supply input end, and a second end of the sixth resistor is connected with a negative electrode of the voltage-stabilizing diode and a first end of the third capacitor; and the anode of the voltage stabilizing diode and the second end of the third capacitor are grounded.
Optionally, the low-voltage power supply power-down protection circuit further includes an EMC filter circuit, an anti-reverse connection circuit, and a filter circuit;
the input of EMC filter circuit with the second low voltage power is connected, EMC filter circuit's output with prevent reverse connection circuit's input and connect, prevent reverse connection circuit's output with filter circuit's input is connected, filter circuit's output with the second power input is connected.
In order to achieve the above object, the present invention further provides a low voltage power supply power-down protection device, which includes the low voltage power supply power-down protection circuit as described above.
According to the technical scheme, the comparison switch circuit is triggered to be turned off when the storage battery of the electric automobile is powered off, and the power supply of the execution circuit is cut off by turning off the comparison switch circuit, so that the execution circuit does not execute ASC operation, and the IGBT can be prevented from being damaged due to the fact that the ASC operation is executed under the condition that the driving voltage is insufficient.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a block diagram of the low voltage power supply power down protection circuit according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of an embodiment of the comparison switch circuit of FIG. 1;
FIG. 3 is a block diagram of another embodiment of the power down protection circuit for a low voltage power supply of the present invention;
FIG. 4 is a schematic circuit diagram of an embodiment of the signal detection circuit shown in FIG. 3;
FIG. 5 is a block diagram of an embodiment of the execution circuit of FIG. 3;
fig. 6 is a block diagram of the power down protection circuit for low voltage power supply according to another embodiment of the present invention.
The reference numbers illustrate:
| Vin1 | a first low voltage power supply | Vin2 | Second low voltage power supply |
| V1 | A first power supply input terminal | V2 | Second power supply input terminal |
| V3 | Third power input terminal | IN | Execution |
| 10 | |
20 | |
| 30 | |
40 | |
| 50 | |
60 | |
| 70 | Filter circuit | R1～R7 | First to seventh resistors |
| T | Voltage stabilizing diode | C1～C3 | First to third capacitors |
| Q1 | A first transistor | Q2 | |
| 101 | |
102 | |
| 201 | |
202 | Active short circuit execution circuit |
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and back … …) are involved in the embodiment of the present invention, the directional indications are only used to explain the relative positional relationship between the components, the movement situation, and the like in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indications are changed accordingly.
In addition, if there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
Fig. 1 is a block diagram of a power-down protection circuit for a low-voltage power supply according to an embodiment of the present invention.
Referring to fig. 1, the low voltage power fail-safe circuit includes a first power input terminal V1 in communication with a first low voltage power Vin1, a second power input terminal V2 in communication with a second low voltage power Vin2, a comparison switch circuit 10 and an execution circuit 30;
the first comparing terminal of the comparing switch circuit 10 is connected to the first power input terminal V1, the second comparing terminal of the comparing switch circuit 10 is connected to the second power input terminal V2, the power input terminal of the comparing switch circuit 10 is connected to the first low voltage source Vin1, and the power output terminal of the comparing switch circuit 10 is connected to the power source terminal of the executing circuit 20.
The comparison switch circuit 10 has two states of off and on, and has the following characteristics: when the voltage of the first comparison end of the comparison switch circuit 10 is greater than the voltage of the second comparison end thereof, the comparison switch circuit 10 is turned off; when the voltage of the first comparing terminal of the comparing switch circuit 10 is smaller than the voltage of the second comparing terminal thereof, the comparing switch circuit 10 is turned on.
The execution circuit 20 is a hardware ASC (active short circuit) execution circuit for executing an ASC operation according to an execution signal inputted from the outside when the comparison switch circuit 10 is turned on.
The voltage inputted from the second power input terminal V2 is provided by the battery positive electrode (KL30) in the electric vehicle, i.e. the second low voltage source Vin2, via an EMC filter circuit 50, an anti-reverse circuit 60 and a filter circuit 70.
It should be noted that, in the present embodiment, the first low-voltage power Vin1 communicated with the first power input terminal V1 is taken from a weak-side power supply which is not related to the triggering of the hardware ASC and has a relatively slow power-down speed, for example, a trigger signal for setting the hardware ASC is provided by an SBC (single board computer), and the second low-voltage power Vin2 is also provided by the SBC, so that the first low-voltage power Vin1 communicated with the first power input terminal V1 and supplying power to the first power input terminal V1 selects a low-voltage power supply generated by a non-SBC, and selects a low-voltage power supply with the slowest power-down speed from the low-voltage power supplies generated by the non-SBC; the first low voltage power supply, i.e. supplying the first power supply input V1, is not selected from the low voltage power supplies generated by the SBC. With the arrangement, in the case of power failure of the non-electric vehicle battery, since the first low-voltage power source Vin1 communicated with the first power input terminal V1 is irrelevant to hardware ASC triggering, common cause failure can be avoided, and the execution circuit 20 can normally execute ASC operation.
Alternatively, in a specific embodiment, the first power input terminal V1 may be directly connected to the power input terminal of the comparison switch circuit 10, so that the voltage inputted from the first power input terminal V1 is used as the reference voltage of the comparison switch circuit 10 and is also used for supplying power to the execution circuit 20. Of course, the power input of the comparison switch circuit 10 may also be connected or connected to other low-voltage power sources, wherein the other low-voltage power sources are selected from weak-side power sources which have no relation to hardware ASC triggering and have relatively slow power-down speed.
The specific working principle is as follows: when the KL30 (positive electrode of the battery) of the electric vehicle is in a non-power-down state, that is, when the second low-voltage power source Vin2 is not powered down, the voltage input by the second power input terminal V2 is normal, specifically, the voltage input by the second power input terminal V2 is greater than the voltage input by the first power input terminal V1, and the comparison switch circuit 10 is turned on. When the comparison switch circuit 10 is in the on state, the first power supply input terminal V1 supplies power to the execution circuit 20 through the on comparison switch circuit 10, in this case, if an execution signal is input to the execution circuit 20 from the outside, the execution circuit 20 performs the ASC operation, and if no execution signal is input to the execution circuit 20 from the outside, the execution circuit 20 does not perform the ASC operation.
When the KL30 of the electric vehicle is powered down, the voltage input by the second power input terminal V2 will gradually decrease, and when the voltage input by the second power input terminal V2 is lower than the voltage input by the first power input terminal V1, which indicates that the driving voltage is insufficient at this time, the IGBT will be damaged when the ASC operation is performed under the condition of insufficient driving voltage, and at this time, the comparison switch circuit 10 is switched from the on state to the off state. When the comparison switch circuit 20 is turned off, the first power supply input terminal V1 is electrically disconnected from the execution circuit 20, and the execution circuit 20 is powered off. After the execution circuit 20 is powered off, the execution circuit 20 does not execute the ASC operation regardless of whether an execution signal is input to the execution circuit 20 from the outside. So set up, make executive circuit 20 not carry out the ASC operation by cutting off the power supply of executive circuit 20 when KL30 loses power to can avoid leading to carrying out the ASC operation under the drive voltage is not enough because KL30 loses power, and then lead to the IGBT to be damaged, and so set up need backup drive power supply, thereby can save the cost of electric automobile.
According to the technical scheme, the comparison switch circuit 10 is triggered to be turned off when the storage battery of the electric automobile is powered off, and the power supply of the execution circuit 20 is cut off by turning off the comparison switch circuit 10, so that the execution circuit 20 cannot execute ASC operation, the IGBT can be prevented from being damaged due to the fact that the ASC operation is executed under the condition of insufficient driving voltage, a driving power supply does not need to be backed up, the cost of the electric automobile can be reduced, and the complexity of PCB design of the electric automobile can be reduced.
Optionally, referring to fig. 2, in an embodiment, the comparison switch circuit 10 includes a comparison circuit 101 and a switch circuit 102;
the positive input end of the comparator 101 is the first comparison end of the comparison switch circuit 10, the negative input end of the comparator 101 is the second comparison end of the comparison switch circuit 10, and the output end of the comparator 101 is connected to the controlled end of the switch circuit 102; the power input terminal of the switch circuit 102 is the power input terminal of the comparison switch circuit 10, and the power output terminal of the switch circuit 102 is the power output terminal of the comparison switch circuit 10.
The comparison circuit 101 may be selected as a comparator, and the comparison circuit 101 has the following characteristics: when the voltage of the positive input end of the comparison circuit 101 is greater than the voltage of the negative input end thereof, the comparison circuit 101 outputs a high level; when the voltage of the positive input terminal of the comparator circuit 101 is smaller than the voltage of the negative input terminal thereof, the comparator circuit 101 outputs a low level.
The switching circuit 102 has two states of off and on, and may be implemented by a circuit composed of a triode or a MOS transistor. In this embodiment, the switch circuit 102 may be selected as a low-level conducting switch circuit.
It is to be understood that in other embodiments, if the positive input terminal of the comparison circuit 101 is connected to the second power input terminal V2 and the negative input terminal of the comparison circuit 102 is connected to the first power input terminal V1, the switch circuit 102 can be selected as a high-level conducting switch circuit.
The specific working principle is as follows: when the KL30 of the electric vehicle is in a non-power-down state, the voltage input by the second power input terminal V2 is greater than the voltage input by the first power input terminal V1, so the voltage at the positive input terminal of the comparison circuit 101 is less than the voltage at the negative input terminal thereof, the comparison circuit 101 outputs a low-level electrical signal to the controlled terminal of the switch circuit 102, and the switch circuit 102 is turned on. When the switch circuit 102 is turned on, the first power input terminal V1 supplies power to the execution circuit 20 through the turned-on switch circuit 102, in which case the execution circuit 20 performs the ASC operation if an execution signal is inputted to the execution circuit 20 from the outside, and the execution circuit 20 does not perform the ASC operation if no execution signal is inputted to the execution circuit 20 from the outside.
When the KL30 of the electric vehicle is powered off, the voltage input by the second power input terminal V2 gradually decreases, and when the voltage input by the second power input terminal V2 is lower than the voltage input by the first power input terminal V1, the voltage of the positive input terminal of the comparison circuit 101 is greater than the voltage of the negative input terminal thereof, the comparison circuit 101 outputs a high-level electrical signal to the controlled terminal of the switch circuit 102, and the switch circuit 102 is switched from the on state to the off state. When the switch circuit 102 is turned off, the first power input terminal V1 is electrically disconnected from the execution circuit 20, and the execution circuit 20 is powered off. After the execution circuit 20 is powered off, the execution circuit 20 does not execute the ASC operation regardless of whether an execution signal is input to the execution circuit 20 from the outside. The present embodiment causes the execution circuit 20 to stop performing the ASC operation by cutting off the power supply to the execution circuit 20 when the KL30 is powered down, so that it is possible to avoid that the IGBT is damaged by performing the ASC operation in the case where the driving voltage is insufficient.
In an embodiment, the switch circuit 102 may be composed of MOS transistors, and the MOS transistor in the switch circuit 102 adopts a P-channel MOS transistor, which is controlled to be turned off by a high-level electrical signal and to be turned on by a low-level signal, so that the execution circuit 20 cannot execute the ASC operation after the switch circuit 102 is turned off; in practical applications, the MOS transistor in the switch circuit 102 may also be an N-channel MOS transistor, in which case, the negative input of the comparison circuit 101 is connected to the first power input terminal V1, the positive input is connected to the second power input terminal V2, the comparison circuit 101 may be controlled to be turned off by outputting an electrical signal with a low level, and the comparison circuit 101 may be controlled to be turned on by outputting an electrical signal with a high level, which may cause an increase in cost. Therefore, if the positive input terminal of the comparator 101 is connected to the first power input terminal V1 and the negative input terminal of the comparator 101 is connected to the second power input terminal V2, the switch circuit 102 is selected to be a low-level conducting switch circuit, which can reduce the cost.
Optionally, the switch circuit 102 may also be formed by a triode, the triode in the switch circuit 102 may be a PNP triode, and the comparison circuit 101 may control the PNP triode to be turned off by a high-level electrical signal. The transistor in the switch circuit 102 may also be an NPN transistor, in which case, the negative input of the comparison circuit 101 is connected to the first power input terminal V1, the positive input is connected to the second power input terminal V2, the comparison circuit 101 may be controlled to turn off by outputting an electrical signal with a low level, and the comparison circuit 101 may be controlled to turn on by outputting an electrical signal with a high level, which may increase the cost.
Optionally, referring to fig. 2, in an embodiment, the switch circuit 102 includes a first resistor R1, a second resistor R2, and a first transistor Q1;
a first terminal of the first resistor R1 is connected to the first power input terminal V1, a second terminal of the first resistor R1 is connected to a first terminal of a second resistor R2, the first terminal of the second resistor R2 is a controlled terminal of the switch circuit 102, and a second terminal of the second resistor R2 is connected to a controlled terminal of a first transistor Q1; the input terminal of the first transistor Q1 is the power input terminal of the switch circuit 102, and the output terminal of the first transistor Q1 is the power output terminal of the switch circuit 102.
The first transistor Q1 may be a P-MOS transistor or a PNP transistor.
The specific working principle is as follows: when the KL30 of the electric vehicle is in a non-power-down state, the comparison circuit 101 outputs a low-level electrical signal to the controlled terminal of the first transistor Q1, the first transistor Q1 is turned on, and the first power input terminal V1 supplies power to the execution circuit 20 through the turned-on first transistor Q1.
When the KL30 is powered down, the comparison circuit 101 outputs an electrical signal with a high level to the controlled terminal of the first transistor Q1, the first transistor Q1 is turned off, the first power input terminal V1 is electrically disconnected from the execution circuit 20, and the execution circuit 20 is powered down.
Optionally, referring to fig. 3, IN an embodiment, the low-voltage power supply power-down protection circuit further includes a signal detection circuit 30 and an execution signal input terminal IN;
the input terminal of the signal detection circuit 30 is connected to the execution signal input terminal IN, and the output terminal of the signal detection circuit 30 is connected to the signal input terminal of the execution circuit 20.
The signal detection circuit 30 is used for detecting whether an execution signal is input to the execution signal input terminal IN, and when the execution signal is input, the execution signal is transmitted to the execution circuit 20 to trigger the execution circuit 20 to execute the ASC operation. It should be noted that, because the battery of the electric vehicle may have a situation of multiple power-down re-turn-on, that is, a shaking situation, and the power-down re-turn-on process is often accompanied with a series of initial processes such as chip initialization, in this process, once the ASC signal is enabled, and the driving voltage is not completely established, a situation may occur that the IGBT is not in saturated conduction and then the ASC operation is performed. Therefore, in order to avoid the occurrence of the case where the IGBT is not turned on in saturation and the ASC operation is performed, the delay time of the signal detection circuit 30 is set to be longer than the delay time required for the driving voltage to rise to satisfy the IGBT turning on in saturation.
Optionally, referring to fig. 4, in an embodiment, the signal detection circuit 30 includes a third power input terminal V3, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first capacitor C1, a second capacitor C2, and a second transistor Q2;
a first terminal of the third resistor R3 is an input terminal of the signal detection circuit 30, a second terminal of the third resistor R3 is connected to the controlled terminal of the second transistor Q2, a second terminal of the third resistor R3 is connected to a first terminal of a fourth resistor R4, and a second terminal of the third resistor R3 is connected to a first terminal of the first capacitor; the second terminal of the fourth resistor R4, the output terminal of the second transistor Q2, and the second terminal of the first capacitor C1 are all grounded;
a first end of the fifth resistor R5 is connected to the third power input terminal V3, a second end of the fifth resistor R5 is an output terminal of the signal detection circuit 30, and a second end of the fifth resistor R5 is connected to an input terminal of the second transistor Q2; and the second terminal of the fifth resistor R5 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is grounded.
In this embodiment, the third power input end V3 may be connected to the first low-voltage power source Vin1, or may be another weak-current power source that has no relation with the triggering of the hardware ASC and has a relatively slow power-down speed (for example, if the hardware ASC signal is triggered by an SBC, the low-voltage power source VAUX is also generated by the SBC, and the power is supplied without using the VAUX power generated by the SBC).
In this embodiment, the second transistor Q2 may be a transistor or a MOS transistor, and for convenience of description, the second transistor Q2 is a high-level conducting transistor, and the execution circuit 20 executes an ASC operation when receiving a high-level electrical signal.
The specific working principle is as follows: when the execution signal input terminal IN inputs an electric signal of a high level, the second transistor Q2 is turned on. When the second transistor Q2 is turned on, the signal input terminal of the execution circuit 20 is at a low level, and the execution circuit 20 does not perform the ASC operation.
When the execution signal input terminal IN inputs the electric signal of the low level, the second transistor Q2 is turned off. When the second transistor Q2 is turned off, the signal input terminal of the execution circuit 20 is pulled up to a high level by the fifth resistor R5, and if the comparison switch circuit 10 is also turned on at this time, the execution circuit 20 performs an ASC operation.
Alternatively, the second transistor Q2 is a transistor turned on at a low level, and the execution circuit 20 executes an ASC operation when receiving an electrical signal at a low level.
The specific working principle is as follows: when the execution signal input terminal IN inputs the electric signal of the low level, the second transistor Q2 is turned on. When the second transistor Q2 is turned on, the signal input terminal of the execution circuit 20 is at a low level, and if the comparison switch circuit 10 is also turned on at this time, the execution circuit 20 performs an ASC operation.
When the execution signal input terminal IN inputs an electric signal of a high level, the second transistor Q2 is turned off. When the second transistor Q2 is turned off, the signal input terminal of the execution circuit 20 is pulled up to a high level by the fifth resistor R5, and the execution circuit 20 does not perform the ASC operation.
It should be noted that the execution circuit 20 needs to satisfy two conditions, namely, the comparison switch circuit 10 is turned on, the first power input terminal V1 supplies power to the execution circuit 20, and the execution circuit 20 receives the execution signal sent by the signal detection circuit 30 and instructing to execute the ASC operation.
Optionally, referring to fig. 5, in an embodiment, the execution circuit 20 includes a digital isolator 201 and an active short execution circuit 202;
the power source terminal of the digital isolator 201 is the power source terminal of the execution circuit 20, the signal input terminal of the digital isolator 201 is the signal input terminal of the execution circuit 20, and the signal output terminal of the digital isolator 201 is connected to the input terminal of the active short execution circuit 202.
The digital isolator 201 is used for transmitting an execution signal to the active short circuit execution circuit 202, and has strong anti-interference capability, so as to ensure the stability and reliability of the system.
The active short circuit execution circuit 202 is used for executing an ASC operation.
The specific working principle is as follows: when KL30 is in the non-powered-down state, comparison switch circuit 10 is turned on. When the comparison switch circuit 10 is turned on, the first power input terminal V1 supplies power to the digital isolator 201 through the turned-on comparison switch circuit 10, in this case, if an execution signal is input to the digital isolator 201 by the signal detection circuit 30, the digital isolator 201 transmits the execution signal to the active short circuit execution circuit 202 to drive the active short circuit execution circuit 202 to execute the ASC operation.
When the KL30 is powered down, the voltage input by the second power input terminal V2 gradually decreases, and when the voltage input by the second power input terminal is lower than the voltage input by the first power input terminal V1, the comparison switch circuit 10 is turned off, and the digital isolator 201 is powered down, in this case, no matter whether the signal detection circuit 30 detects an execution signal, the digital isolator 201 cannot transmit the execution signal to the active short circuit execution circuit 202, and the active short circuit execution circuit 202 does not execute the ASC operation.
Optionally, referring to fig. 6, in an embodiment, the low voltage power supply power down protection circuit further includes a voltage stabilizing circuit 40; the input end of the voltage stabilizing circuit 40 is connected with the first low voltage power supply Vin1, and the output end of the voltage stabilizing circuit 40 is connected with the first power supply input end V1.
The voltage stabilizing circuit 40 is used for stabilizing the voltage output by the first low voltage source Vin1 to a certain voltage, and then providing a reference voltage for the comparison switch circuit 10, and at the same time, supplying power for the execution circuit 20.
Optionally, referring to fig. 6, in an embodiment, the voltage regulating circuit 40 includes a sixth resistor R6, a zener diode T, and a third capacitor C3; a first end of the sixth resistor R6 is connected to the first low voltage source Vin1, a second end of the sixth resistor R6 is connected to the first power input terminal V1, and a second end of the sixth resistor R6 is connected to the cathode of the zener diode T and the first end of the third capacitor C3; the anode of the zener diode T and the second terminal of the third capacitor C3 are grounded.
The zener diode T is configured to stabilize a voltage input by the first low voltage source Vin1 to a certain voltage.
Optionally, referring to fig. 6, in an embodiment, the low-voltage power supply power-down protection circuit further includes an EMC filter circuit 50, an anti-reverse connection circuit 60, and a filter circuit 70;
the input end of the EMC filter circuit 50 is connected to the second low voltage source Vin2, the output end of the EMC filter circuit 50 is connected to the input end of the anti-reverse connection circuit 60, the output end of the anti-reverse connection circuit 60 is connected to the input end of the filter circuit 70, and the output end of the filter circuit 70 is connected to the second power source input end V2.
The EMC filter circuit 50 is used for eliminating and suppressing electromagnetic interference in the electric energy output by the second low-voltage power supply Vin 2.
The reverse connection preventing circuit 60 is used for preventing the rear-end circuit from being damaged due to reverse connection of the positive electrode and the negative electrode of the second low-voltage power supply Vin2, specifically, when the positive electrode and the negative electrode of the second low-voltage power supply Vin2 are correctly connected, electric energy output by the second low-voltage power supply Vin2 can be conducted to the rear-end circuit, and when the positive electrode and the negative electrode of the second low-voltage power supply Vin2 are incorrectly connected, the rear-end circuit is powered.
The filter circuit 70 is configured to filter out ripples in the electric power output by the second low-voltage power source Vin 2. Optionally, the filter circuit 70 includes a seventh resistor R7 and a fourth capacitor C4, a first end of the seventh resistor R7 is connected to the output end of the anti-reverse connection circuit 60, a first end of the seventh resistor R7 is connected to a first end of the fourth capacitor C4, and a second end of the fourth capacitor C4 is grounded; the second terminal of the seventh resistor R7 is the second power input terminal V2, i.e., the second terminal of the seventh resistor R7 is connected to the second comparing terminal of the comparison switch circuit 10.
The invention also provides a low-voltage power supply power-down protection device, which comprises the low-voltage power supply power-down protection circuit, and the detailed structure of the low-voltage power supply power-down protection circuit can refer to the embodiment and is not described again; it can be understood that, because the low-voltage power supply power-down protection circuit is used in the low-voltage power supply power-down protection device of the present invention, embodiments of the low-voltage power supply power-down protection device of the present invention include all technical solutions of all embodiments of the low-voltage power supply power-down protection circuit, and the achieved technical effects are also completely the same, and are not described herein again.
The above description is only an alternative embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (11)
1. The low-voltage power supply power-down protection circuit is characterized by comprising a first power supply input end communicated with a first low-voltage power supply, a second power supply input end communicated with a second low-voltage power supply, a comparison switch circuit and an execution circuit;
a first comparison end of the comparison switch circuit is connected with the first power supply input end, a second comparison end of the comparison switch circuit is connected with the second power supply input end, the power supply input end of the comparison switch circuit is communicated with the first low-voltage power supply, and the power supply output end of the comparison switch circuit is connected with the power supply end of the execution circuit;
and the comparison switch circuit is used for disconnecting the input power supply of the execution circuit according to a preset mode when the second low-voltage power supply is powered off so as to stop the execution circuit from executing the active short-circuit operation.
2. The power down protection circuit for a low voltage power supply of claim 1, wherein a power input of the comparison switch circuit is coupled to the first power input.
3. The low voltage power supply power down protection circuit of claim 2, wherein the comparison switch circuit comprises a comparison circuit and a switch circuit;
the positive input end of the comparison circuit is a first comparison end of the comparison switch circuit, the negative input end of the comparison circuit is a second comparison end of the comparison switch circuit, and the output end of the comparison circuit is connected with the controlled end of the switch circuit;
the power supply input end of the switch circuit is the power supply input end of the comparison switch circuit, and the power supply output end of the switch circuit is the power supply output end of the comparison switch circuit.
4. The power down protection circuit for low voltage power supply of claim 3, wherein said switching circuit comprises a first resistor, a second resistor and a first transistor;
a first end of the first resistor is connected with the first power supply input end, a second end of the first resistor is connected with a first end of the second resistor, the first end of the second resistor is a controlled end of the switch circuit, and the second end of the second resistor is connected with a controlled end of the first transistor;
the input end of the first transistor is the power supply input end of the switch circuit, and the output end of the first transistor is the power supply output end of the switch circuit.
5. The low voltage power supply fail safe circuit of claim 1, wherein the low voltage power supply fail safe circuit further comprises a signal detection circuit and an execution signal input;
the input end of the signal detection circuit is connected with the execution signal input end, and the output end of the signal detection circuit is connected with the signal input end of the execution circuit.
6. The power down protection circuit for low voltage power supply of claim 5, wherein the signal detection circuit comprises a third power input terminal, a third resistor, a fourth resistor, a fifth resistor, a first capacitor, a second capacitor and a second transistor;
a first end of the third resistor is an input end of the signal detection circuit, a second end of the third resistor is connected with a controlled end of the second transistor, a second end of the third resistor is connected with a first end of the fourth resistor, and a second end of the third resistor is connected with a first end of the first capacitor; a second end of the fourth resistor, an output end of the second transistor and a second end of the first capacitor are grounded;
a first end of the fifth resistor is connected with the third power supply input end, a second end of the fifth resistor is an output end of the signal detection circuit, and a second end of the fifth resistor is connected with an input end of the second transistor;
and the second end of the fifth resistor is connected with the first end of the second capacitor, and the second end of the second capacitor is grounded.
7. The low voltage power supply power down protection circuit of claim 5, wherein the execution circuit comprises a digital isolator and an active short execution circuit;
the power supply end of the digital isolator is the power supply end of the execution circuit, the signal input end of the digital isolator is the signal input end of the execution circuit, and the signal output end of the digital isolator is connected with the input end of the active short circuit execution circuit.
8. The low voltage power supply fail safe circuit of any one of claims 1 to 7, wherein the low voltage power supply fail safe circuit further comprises a voltage regulator circuit;
the input end of the voltage stabilizing circuit is connected with the first low-voltage power supply, and the output end of the voltage stabilizing circuit is connected with the input end of the first power supply.
9. The power down protection circuit for a low voltage power supply of claim 8, wherein the voltage regulation circuit comprises a sixth resistor, a zener diode, and a third capacitor;
a first end of the sixth resistor is connected with the first low-voltage power supply, a second end of the sixth resistor is connected with the first power supply input end, and a second end of the sixth resistor is connected with a negative electrode of the voltage-stabilizing diode and a first end of the third capacitor; and the anode of the voltage stabilizing diode and the second end of the third capacitor are grounded.
10. The low voltage power supply fail safe circuit of claim 8, wherein the low voltage power supply fail safe circuit further comprises an EMC filter circuit, an anti-reverse circuit, and a filter circuit;
the input of EMC filter circuit with the second low voltage power is connected, EMC filter circuit's output with prevent reverse connection circuit's input and connect, prevent reverse connection circuit's output with filter circuit's input is connected, filter circuit's output with the second power input is connected.
11. A low voltage power supply power down protection device, characterized in that it comprises a low voltage power supply power down protection circuit according to any of claims 1-10.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010741597.0A CN111817257A (en) | 2020-07-28 | 2020-07-28 | Low-voltage power supply power-down protection circuit and low-voltage power supply power-down protection device |
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| CN202010741597.0A CN111817257A (en) | 2020-07-28 | 2020-07-28 | Low-voltage power supply power-down protection circuit and low-voltage power supply power-down protection device |
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| CN111817257A true CN111817257A (en) | 2020-10-23 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023040368A1 (en) * | 2021-09-17 | 2023-03-23 | 精进电动科技股份有限公司 | Standby power supply system for parking controller |
-
2020
- 2020-07-28 CN CN202010741597.0A patent/CN111817257A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023040368A1 (en) * | 2021-09-17 | 2023-03-23 | 精进电动科技股份有限公司 | Standby power supply system for parking controller |
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Address after: 215000 52 tianedang Road, Yuexi, Wuzhong District, Suzhou City, Jiangsu Province Applicant after: Suzhou Huichuan United Power System Co.,Ltd. Address before: 215000 52 tianedang Road, Yuexi, Wuzhong District, Suzhou City, Jiangsu Province Applicant before: SUZHOU HUICHUAN UNITED POWER SYSTEM Co.,Ltd. |