WO2020087270A1 - Power failure protection circuit, apparatus and system used for vehicle-mounted device - Google Patents

Abstract

A power failure protection circuit, apparatus and system used for a vehicle-mounted device; a single-chip machine control unit (108) outputs a control instruction when detected that a vehicle power supply (201) experiences power failure; a charging and discharging unit (103) is used to discharge and output a first preset voltage signal when the vehicle power supply (201) experiences power failure so as to continue to supply power to the single-chip machine control unit (108), a system control unit (109), and a hard drive unit (110) so that, according to the control instruction, the system control unit (109) controls the hard drive unit (110) to store data that is recorded in real time within a preset period of time. As such, when the vehicle power supply (201) experiences power failure, the hard drive unit (110) has sufficient time to store data that is recorded in real time, which prevents the problem of data loss and solves the problem with existing power failure protection technologies used for vehicle-mounted devices wherein a driving recorder having a 3.5-in hard drive cannot record and store data in real time when an external power supply is disrupted.

Description

Power-off protection circuit, device and system for vehicle-mounted equipment Technical field

This solution belongs to the technical field of electronic circuits, and particularly relates to a power-off protection circuit, device and system for vehicle-mounted equipment.

Background technique

The national standard GB / T 19056-2012 document stipulates that the operating vehicle on the road is equipped with a car driving recorder. In the case of a power failure, it provides detailed requirements for hard disk storage. It clearly stipulates that the car driving recorder must be able to complete Record and analyze vehicle video data. However, due to the complex internal and external environmental impacts of the car, especially in the event of vehicle collisions, man-made destruction, and other factors that cause a sudden power failure of the car driving recorder, the internal hard disk of the car driving recorder cannot work because of a sudden power failure. Real-time, complete video footage is recorded, which cannot provide an effective basis for later evidence collection. How to accurately solve similar problems is a problem that all car driving recorder design manufacturers need to consider.

In order to solve the above problems, the current general practices are mainly the following two:

The first method: add UPS (Uninterruptible) to the front of the car driving recorder device Power System / Uninterruptible Power Supply), which uses UPS to power the vehicle's driving recorder. This solution can ensure that the vehicle's driving recorder can continue to be powered when the external power supply is turned off, but it has certain limitations and disadvantages. In the following two aspects:

1) The cost is expensive, and the cost of UPS needs to be increased;

2) With reference to Figure 1, when the vehicle power supply to the UPS front-end power supply is damaged (cable A), the car driving recorder can continue to complete the recording. However, if the area from the back-end power supply of the UPS to the car driving recorder is damaged (cable B), the internal hard disk of the car driving recorder will not work even if the power is turned off in an instant, and the real-time complete video screen cannot be recorded, so it has certain limitation.

The second method: In order to solve the first problem, some design manufacturers began to add a farad capacitor inside the car driving recorder, that is, when the external power supply is destroyed, the storage characteristics of the farad capacitor are used to power the car driving recorder. Compared with the first method, it can not only ensure the cost advantage, but also ensure that the car driving recorder is not affected by external power failure. However, Farad capacitors have low voltage resistance and low capacity, and are only suitable for 2.5-inch hard drives and other low-power car driving recorders. Due to the large power consumption of 3.5-inch hard drives, Farad capacitors cannot power them according to the existing architecture. In the existing architecture, it is undesirable to directly use the 12V power supply of the farad capacitor to power the hard disk. After the external power supply is turned off, the farad capacitor begins to discharge and the 12V voltage gradually decreases. The 12V power supply of the hard disk must not be less than 10% of the working power supply. This causes the external power to be turned off. At the same time, the voltage drop causes the 12V of the hard disk to stop working immediately. The system control unit cannot complete the storage and unloading of the hard disk data, and there is a risk of hard disk data loss. Under the increasing influence of the high-definition monitoring environment on the hard disk capacity requirements, car driving recorders using 3.5-inch large-capacity hard disks are imminent.

Therefore, the existing power-off protection technology for in-vehicle equipment has the problem that the 3.5-inch hard disk drive recorder cannot record and store data in real time due to the destruction of the external power supply.

technical problem

The purpose of this solution is to provide a power-off protection circuit, device and system for in-vehicle equipment, aiming to solve the existing power-off protection technology for in-vehicle equipment. In the case of power failure, it is impossible to record and store data in real time.

Technical solution

The first aspect of the present solution provides a power-off protection circuit for a vehicle-mounted device. The power-off protection circuit includes:

Transformer unit, first buck unit, second buck unit, third buck unit, current limiting unit, charge and discharge unit, and boost unit;

The input terminal of the voltage transformation unit is connected to a vehicle power source, the output terminal of the voltage transformation unit is connected to the charge and discharge unit through the current limiting unit, the input terminal of the first voltage reduction unit, and the second voltage reduction unit The input end of the unit and the input end of the boosting unit are respectively connected to the current limiting unit, the output end of the first step-down unit is connected to a microcontroller control unit, and the output end of the second step-down unit is connected to a system control unit , The output end of the step-up unit is connected to the hard disk unit on the one hand, and connected to the hard disk unit through the third step-down unit on the other hand;

The voltage signal output by the vehicle power supply undergoes voltage conversion by the transformer unit and then outputs a first preset voltage signal. On the one hand, the first preset voltage signal charges the charging and discharging unit through the current limiting unit On the other hand, after performing voltage reduction processing through the first voltage step-down unit and the second voltage step-down unit, respectively, a second preset voltage signal is output to supply power to the single-chip microcomputer control unit and the system control unit respectively; In another aspect, after the boosting process is performed by the boosting unit, a third preset voltage signal is output to supply power to the hard disk unit, and the third preset voltage signal is stepped down by the third step-down unit After processing, a fourth preset voltage signal is output to supply power to the hard disk unit;

The single-chip microcomputer control unit outputs a control instruction when the vehicle power supply is powered off, and the charge and discharge unit is used to discharge the first preset voltage signal to maintain the The single-chip microcomputer control unit, the system control unit and the hard disk unit supply power so that the system control unit controls the hard disk unit to store the real-time recorded data within a preset time according to the control instruction.

The second aspect of the present solution provides a power-off protection device for a vehicle-mounted device, including a single-chip microcomputer control unit, a system control unit, and a hard disk unit. The power-off protection device further includes a power-off protection circuit as described above.

The third aspect of the present solution provides a power-off protection system for vehicle-mounted equipment, including a vehicle power supply, and the power-off protection system further includes a power-off protection device as described above.

Beneficial effect

This solution provides a power-off protection circuit, device and system for vehicle-mounted equipment. The single-chip microcomputer control unit outputs a control command when the vehicle power supply is detected to be powered off. The charge and discharge unit is used to discharge the output when the vehicle power supply is powered off The first preset voltage signal maintains power supply to the microcontroller control unit, the system control unit and the hard disk unit, so that the system control unit controls the hard disk unit to store the real-time recorded data within a preset time according to the control instruction. This realizes that when the vehicle power supply is powered off, the hard disk unit has enough time to store the real-time recorded data, avoiding the problem of data loss, and solving the existing power-off protection technology for on-board equipment. The problem that the drive recorder of the hard disk cannot record and store data in real time due to the destruction of the external power supply.

BRIEF DESCRIPTION

FIG. 1 is a schematic diagram of a connection structure for supplying power to a vehicle traveling data recorder according to the prior art.

FIG. 2 is a diagram illustrating an example of a unit structure of a power-off protection circuit for a vehicle-mounted device provided by an embodiment of the present solution.

FIG. 3 is a circuit example diagram of a power-off protection circuit for an in-vehicle device provided by an embodiment of this solution.

Embodiments of the invention

In order to make the technical problems, technical solutions, and beneficial effects to be solved by the solution more clear, the following describes the solution in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the solution, and are not used to limit the solution.

The above-mentioned power-off protection circuit, device and system for in-vehicle equipment, through the single-chip microcomputer control unit to output control instructions when the vehicle power supply is detected to be powered off, the charge and discharge unit is used to discharge the first output when the vehicle power supply is powered off The preset voltage signal maintains the power supply to the microcontroller control unit, the system control unit and the hard disk unit, so that the system control unit controls the hard disk unit to store the real-time recorded data within a preset time according to the control instructions. Thus, when the vehicle power supply is cut off, the hard disk unit has enough time to store the data recorded in real time, avoiding the problem of data loss. The above power-off protection circuit, device and system for in-vehicle equipment can be applied to in-vehicle security-related equipment such as in-vehicle digital video recorders, in-vehicle car driving recorders and the like.

FIG. 2 shows a unit structure of a power-off protection circuit for a vehicle-mounted device provided by an embodiment of this solution. For ease of description, only the parts related to this embodiment are shown. The details are as follows:

The above-mentioned power-off protection circuit for in-vehicle equipment includes a transformer unit 101, a first buck unit 104, a second buck unit 105, a third buck unit 107, a current limiting unit 102, a charge and discharge unit 103, and Booster unit 106.

The input terminal of the transformer unit 101 is connected to the vehicle power supply 201, the output terminal of the transformer unit 101 is connected to the charging and discharging unit 103 through the current limiting unit 102, the input terminal of the first step-down unit 104, the input terminal of the second step-down unit 105 and The input terminals of the voltage step-up unit 106 are respectively connected to the current limiting unit 102, the output terminal of the first voltage step-down unit 104 is connected to the microcontroller control unit 108, the output terminal of the second voltage step-down unit 105 is connected to the system control unit 109, and the output of the voltage step-up unit 106 The terminal is connected to the hard disk unit 110 on the one hand, and connected to the hard disk unit 110 through the third voltage reduction unit 107 on the other hand.

The voltage signal output by the vehicle power supply 201 undergoes voltage conversion by the transformer unit 101 and outputs a first preset voltage signal. On the one hand, the first preset voltage signal charges the charging and discharging unit 103 through the current limiting unit 102; After the first step-down unit 104 and the second step-down unit 105 perform step-down processing, they output a second preset voltage signal to supply power to the microcontroller control unit 108 and the system control unit 109 respectively; After the voltage processing, the third preset voltage signal is output to supply power to the hard disk unit 110, and the third preset voltage signal is subjected to the voltage reduction process by the third voltage step-down unit 107, and then the fourth preset voltage signal is output to supply power to the hard disk unit 110 ;

The MCU control unit 108 outputs a control instruction when it detects that the vehicle power supply 201 is powered off, and the charge and discharge unit 103 is used to discharge the first preset voltage signal when the vehicle power supply 201 is powered off to maintain the MCU control unit 108 and the system control unit 109 and the hard disk unit 110 supply power so that the system control unit 109 controls the hard disk unit 110 to store the real-time recorded data within a preset time according to the control instruction.

As an embodiment of the present solution, the voltage value of the first preset voltage signal is 12V, the voltage value of the second preset voltage signal is 3.3V, the voltage value of the third preset voltage signal is 12.4V, and the fourth preset The voltage value of the voltage signal is 5V.

As an embodiment of this solution, when the vehicle power supply 201 is powered off, in order to ensure that data is not lost, it takes enough time for the hard disk unit 110 to be continuously powered on to store the data recorded in real time. When the microcontroller control unit 108 outputs a control instruction when it detects that the vehicle power supply 201 is powered off, the system control unit 109 controls the hard disk unit 110 to store the real-time recorded data within a preset time according to the control instruction. That is, after the vehicle power supply 210 is powered off, the charging and discharging unit 103 can discharge to ensure that the single-chip control unit 108, the system control unit 109, and the hard disk unit 110 can continue to operate for a period of time. This period of time is sufficient for the hard disk unit 110 to store the data recorded in real time.

FIG. 3 shows an example circuit for a power-off protection circuit of an in-vehicle device provided by an embodiment of the present solution. For convenience of description, only parts related to this embodiment are shown. Details are as follows:

As an embodiment of this solution, the current limiting unit 102 includes a current limiting resistor.

As an embodiment of the present solution, the above-mentioned transformer unit 101 is implemented by a transformer chip U1. Since the range of the voltage signal output by the vehicle power supply 201 is 8V ~ 36V, a voltage signal of 12V is output after the voltage conversion by the transformer chip U1.

As an embodiment of this solution, the first step-down unit 104, the second step-down unit 105, and the first

The three step-down units 107 are all implemented with step-down chips. Specifically, the first bucking chip U2 used by the first bucking unit 104 and the second bucking chip U3 used by the second bucking unit 105 may be the same type of bucking chip, both of which step down the voltage signal of 12V After outputting a voltage signal of 3.3V, it supplies power to the microcontroller control unit 108 and the system control unit 109 respectively; the third step-down chip U4 used by the third step-down unit 107 steps down the voltage signal of 12.4V to 5V Voltage signal to the hard disk unit 110.

As an embodiment of this solution, the boosting unit 106 is implemented using a boosting chip U5. The boosting chip U5 is used to boost the voltage signal of 12V to 12.4V and supply power to the hard disk unit 110.

As an embodiment of this solution, the charging and discharging unit 103 includes a farad capacitor.

As an embodiment of this solution, the hard disk unit 110 includes a 3.5-inch hard disk or a 2.5-inch hard disk, and FIG. 3 is represented by a 3.5-inch hard disk.

The solution also provides a power-off protection device for vehicle-mounted equipment, including a single-chip microcomputer control unit, a system control unit, and a hard disk unit. The power-off protection device further includes the power-off protection circuit as described above.

The solution also provides a power-off protection system for vehicle-mounted equipment, including a vehicle power supply, and the power-off protection system further includes a power-off protection device as described above.

The working principle of the above-mentioned power-off protection circuit, device and system for vehicle-mounted equipment will be described below in conjunction with FIGS. 2-3:

Vehicle power supply 201 power supply process:

1) Transformer chip U1 is responsible for the buck-boost processing of the input voltage of vehicle power supply 201: when the input is lower than 12V, it is in boost mode; when the output is higher than 12V, it is in buck mode. The output is set to a fixed 12V. Based on the reason that the output is set to 12V, it is mainly for the industry general standard and the peripheral interface is powered by 12V;

2) The transformer chip U1 outputs 12V to supply power to the back-end system, and charges the farad capacitor through the current limiting resistor, and it is in a constant state after being fully charged;

3) The transformer chip U1 outputs 12V, and after the first buck chip U2 and the second buck chip U3 are stepped down to 3.3V, they supply power to the microcontroller control unit 108 and the system control unit 109, respectively;

4) For the transformer chip U5, the circuit operating conditions input voltage range (3V-60V), the output voltage is set at 12.4V, for the back-end hard disk 12V power supply and the third step-down chip U4 power supply;

5) For the third step-down chip U4, the input is provided by the transformer chip U5 at 12.4V, and the output voltage is set at 5V for the back-end hard disk 5V power supply;

6) The boost output value of the transformer chip U5 is set to 12.4V, which satisfies the operating range of 3.5-inch hard disk power supply 12V ± 10%, and at the same time allows the transformer chip U5 to work independently of the external power on and off, and maintain a stable boost mode . That is, under normal power-on operation, U1 outputs 12V, and the transformer chip U5 boost outputs 12.4V.

Vehicle power supply 201 power down process:

The single-chip microcomputer control unit 108 monitors the situation of the vehicle power supply 201 in real time through the ADC pins. If it detects that the voltage is lower than 7V for 600ms continuously, it is determined as abnormal power failure, and notifies the system control unit 109 to shut down and save the data. After receiving the external power low command (ie, control command) issued by the single-chip microcomputer control unit 108, the system control unit 109 starts to enter the shutdown mode, saves data, and uninstalls the dormant hard disk. Generally, it takes about 4s to complete the data storage, that is, the entire system needs to be turned off when the external power is turned off, as long as the power supply is stable for more than 4s to ensure that the hard disk data will not be lost.

How to keep the system power stable, the performance is as follows:

1) Transformer chip U1 is not working;

2) In the entire system, the power supply of the single-chip microcomputer control unit 108, the system control unit 109, and the hard disk unit 110 are all supported by the discharge of the farad capacitor 103 from 12V;

3) The output voltage of the first step-down chip U1 and the second step-down chip U2 keeps stable when the input drops from 12V, and continues to output 3.3V until the voltage discharge of the farad capacitor 103 is lower than 3.3V;

4) The boost chip U5 is always in boost mode when the input falls from 12V, and the falling process is within the range of 12V-3V. The boost chip U5 is not affected by external power and always maintains the boost state. The stable output is 12.4V. The 3.5-inch hard disk works until the voltage discharge of the farad capacitor 103 is lower than the input threshold of the boost chip U5 by 3V;

5) The working state of the third step-down chip U4 remains unchanged, and the input and output voltages are the same as during normal power-up operation;

6) As can be seen from the above, the voltage of the farad capacitor 103 can be kept stable when the voltage is higher than 3.3V, so the voltage of the farad capacitor 103 slowly drops from 12V and falls from 12V to 3.3V as the effective voltage. Set the parameter of the farad capacitor 103 to 3F, and the theoretical time for the load 3A to drop from 12V to 3.3V according to the calculation formula is (12V-3.3V) * 3F / 3A = 8.7S, that is, the effective voltage time is 8.7S. The effective 8.7S voltage can ensure that the system control unit 109 controls the 3.5-inch hard disk to complete the data storage.

Therefore, the above power-off protection circuit improves the success of data storage, and solves the problem that the 3.5-inch large hard disk power-off data protection cannot be supported in the current automotive market. The power-off protection circuit supports 2.5-inch hard disks or 3.5-inch hard disks; using the boosting characteristics of the circuit, the power-down range of the farad capacitor is improved, and the system wins more time to handle the shutdown process, thereby greatly improving the hard disk Reliability of data storage; its circuit is simple, reliable, stable and low cost.

In summary, the embodiment provides a power-off protection circuit, device and system for vehicle-mounted equipment. The single-chip microcomputer control unit outputs a control command when the power supply of the vehicle is detected, and the charge-discharge unit is used to shut down the vehicle power supply. When the power is on, the first preset voltage signal is discharged to maintain the power supply to the microcontroller control unit, the system control unit and the hard disk unit, so that the system control unit controls the hard disk unit to store the real-time recorded data within a preset time according to the control instruction. This realizes that when the vehicle power supply is powered off, the hard disk unit has enough time to store the real-time recorded data, avoiding the problem of data loss, and solving the existing power-off protection technology for on-board equipment. The problem that the drive recorder of the hard disk cannot record and store data in real time due to the destruction of the external power supply.

In this article, specific examples are used to explain the principle and implementation of the solution. The descriptions of the above embodiments are only used to help understand the method and the core idea of the solution. It should be noted that, for those of ordinary skill in the art, without departing from the principles of this solution, several improvements and modifications can also be made to this solution, and these improvements and modifications also fall within the protection scope of the claims of this solution.

The above is only the preferred embodiment of this solution and is not intended to limit this solution. Any modification, equivalent replacement and improvement made within the spirit and principle of this solution should be included in the protection of this solution Within range.

Claims (10)

1. A power-off protection circuit for vehicle-mounted equipment, characterized in that the power-off protection circuit includes:

   Transformer unit, first buck unit, second buck unit, third buck unit, current limiting unit, charge and discharge unit, and boost unit;

   The input terminal of the voltage transformation unit is connected to a vehicle power source, the output terminal of the voltage transformation unit is connected to the charge and discharge unit through the current limiting unit, the input terminal of the first voltage reduction unit, and the second voltage reduction unit The input end of the unit and the input end of the boosting unit are respectively connected to the current limiting unit, the output end of the first step-down unit is connected to a microcontroller control unit, and the output end of the second step-down unit is connected to a system control unit , The output end of the step-up unit is connected to the hard disk unit on the one hand, and connected to the hard disk unit through the third step-down unit on the other hand;

   The voltage signal output by the vehicle power supply undergoes voltage conversion by the transformer unit and then outputs a first preset voltage signal. On the one hand, the first preset voltage signal charges the charging and discharging unit through the current limiting unit On the other hand, after performing voltage reduction processing through the first voltage step-down unit and the second voltage step-down unit, respectively, a second preset voltage signal is output to supply power to the single-chip microcomputer control unit and the system control unit respectively; In another aspect, after the boosting process is performed by the boosting unit, a third preset voltage signal is output to supply power to the hard disk unit, and the third preset voltage signal is stepped down by the third step-down unit After processing, a fourth preset voltage signal is output to supply power to the hard disk unit;

   The single-chip microcomputer control unit outputs a control instruction when the vehicle power supply is powered off, and the charge and discharge unit is used to discharge the first preset voltage signal to maintain the The single-chip microcomputer control unit, the system control unit and the hard disk unit supply power so that the system control unit controls the hard disk unit to store the real-time recorded data within a preset time according to the control instruction.
2. The power-off protection circuit of claim 1, wherein the current limiting unit includes a current limiting resistor.
3. The power-off protection circuit according to claim 1, wherein the voltage value of the first preset voltage signal is 12V, the voltage value of the second preset voltage signal is 3.3V, and the third The voltage value of the voltage signal is 12.4V, and the voltage value of the fourth preset voltage signal is 5V.
4. The power-off protection circuit according to claim 1, wherein the voltage transformation unit is implemented by a voltage transformation chip.
5. The power-off protection circuit according to claim 1, wherein the first step-down unit,

   Both the second step-down unit and the third step-down unit are implemented by a step-down chip.
6. The power-off protection circuit according to claim 1, wherein the boosting unit is implemented by a boosting chip.
7. The power-off protection circuit of claim 1, wherein the charging and discharging unit includes a farad capacitor.
8. The power-off protection circuit of claim 1, wherein the hard disk unit comprises a 3.5-inch hard disk or a 2.5-inch hard disk.
9. A power-off protection device for vehicle-mounted equipment, including a single-chip microcomputer control unit, a system control unit, and a hard disk unit, characterized in that the power-off protection device further includes the power-off according to any one of claims 1 to 8. protect the circuit.
10. A power-off protection system for vehicle-mounted equipment, including a vehicle power supply, characterized in that the power-off protection system further includes the power-off protection device according to claim 9.