Power failure protection circuit and power failure protection system

Abstract

The utility model provides a power failure protection circuit and a power failure protection system, and relates to the technical field of electronics, the power failure protection circuit comprises a data input module, a power supply monitoring module, a master control monitoring module, a data storage module, a bus connection module and a power supply module, the data input module is electrically connected with the master control monitoring module and the power supply module respectively, and the data storage module is electrically connected with the bus connection module. The receiver receives an input signal. The main control monitoring module is electrically connected with the power supply monitoring module, the data storage module, the bus connection module and the power supply module, and is used for sending a power supply switching signal to the power supply monitoring module; the power supply monitoring module is electrically connected with the data storage module, the bus connection module and the power supply module, a backup power supply is arranged in the power supply monitoring module, and the power supply monitoring module is used for receiving a power supply switching signal and switching the power supply module into the backup power supply for power supply; the data storage module is electrically connected with the bus connection module and the power supply module. The bus connection module is electrically connected with the power supply module. According to the invention, the stability of RAM data writing during power failure can be improved.

Description

Technical Field

[0001] The utility model relates to the field of electronic technology, in particular to a power-off protection circuit and a power-off protection system. Background Art

[0002] In the era of rapid development of electronic information, there are more and more electronic devices, the systems are becoming more and more complex, and the content of flash memory is getting larger and larger. In areas where the power grid fluctuates greatly, the probability of sudden power outage of electronic devices during use will also increase, which will lead to the probability of Flash data loss and product return rate. Especially in the field of wireless communications, when the customer is using it, the system reads and writes the flash memory. At this time, the external power suddenly loses, which is likely to cause operational errors, product data loss and other phenomena.

[0003] The Chinese patent application with announcement number CN213937419U discloses a power-off protection circuit and a display device, including a power-off protection circuit and a display device, wherein the power-off protection circuit includes a detection module and a controller, wherein the detection module is connected to the power board and the controller, and the detection module is used to connect to the power board and the controller respectively, and detect the power-on state of the power board, and output a first detection signal to the controller when the power board loses power; the controller is used to connect to the storage chip and the display screen respectively, and control the storage chip to store data within a preset time according to the first detection signal, and control the display screen to turn off. However, the power-off protection method adopted in the above scheme is capacitor power supply, and the power supply time of such a power-off protection method is short and the voltage fluctuation is large, which is easy to cause content writing failure. Therefore, it is very necessary to provide a power-off protection circuit and a power-off protection system to improve the stability of the power supply voltage during power failure, and then realize the stable writing of RAM data. Utility Model Content

[0004] In view of this, the utility model proposes a power-off protection circuit and a power-off protection system. By setting a data input module, a main control monitoring module, a power monitoring module and a built-in backup power supply in the power monitoring module, when the main control monitoring module detects that the power module loses power, the main control monitoring module controls the power monitoring module to switch the power supply end from the power module to the backup power supply, so as to improve the stability of the power supply voltage during power failure, thereby realizing stable writing of RAM data.

[0005] In a first aspect, the utility model provides a power-off protection circuit, including a data input module, a main control monitoring module, a power monitoring module, a data storage module, a bus connection module and a power module, wherein:

[0006] The data input module is electrically connected to the main control monitoring module and the power supply module respectively, and the data input module is used to receive input signals;

[0007] The main control monitoring module is electrically connected to the power monitoring module, the data storage module, the bus connection module and the power module respectively, and the main control monitoring module is used to send a power switching signal to the power monitoring module;

[0008] The power monitoring module is electrically connected to the data storage module, the bus connection module and the power module respectively, the power monitoring module is equipped with a backup power supply, and the power monitoring module is used to receive the power switching signal and switch the power module to the backup power supply;

[0009] The data storage module is electrically connected to the bus connection module and the power supply module respectively, and the data storage module is used to store the input signal;

[0010] The bus connection module is electrically connected to the power supply module.

[0011] On the basis of the above technical solution, preferably, the data input module includes a data modification unit, a filtering and noise reduction unit and a differential drive unit, the data modification unit is electrically connected to the filtering and noise reduction unit, the filtering and noise reduction unit is electrically connected to the differential drive unit, and the differential drive unit is electrically connected to the main control monitoring module.

[0012] On the basis of the above technical solution, preferably, the filtering and noise reduction unit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a first diode, a second diode, a third diode and a fourth diode, the first common end and the second common end of the first capacitor and the second capacitor are both connected to the data modification unit and the GND end, the first common end and the second common end of the third capacitor and the fourth capacitor are both connected to the data modification unit and the GND end, one end of the first resistor is respectively connected to the third end of the data modification unit, the cathode of the first diode and the differential drive unit, the other end of the first resistor is respectively connected to the fourth end of the data modification unit, the cathode of the second diode and the differential drive unit, one end of the second resistor is respectively connected to the first end of the data modification unit, the cathode of the third diode and the differential drive unit, the other end of the second resistor is respectively connected to the second end of the data modification unit, the cathode of the fourth diode and the differential drive unit, and the anode of the first diode, the anode of the second diode, the anode of the third diode and the anode of the fourth diode are grounded together.

[0013] Further preferably, the differential drive unit includes a differential drive chip and a fifth capacitor, the first pin of the differential drive unit is respectively connected to the power supply module and one end of the fifth capacitor, the other end of the fifth capacitor is grounded, the second pin and the third pin of the differential drive unit are both connected to the main control monitoring module, the fourth pin of the differential drive unit is grounded, and the fifth pin, the sixth pin, the seventh pin and the eighth pin of the differential drive unit are all connected to the filtering and noise reduction unit.

[0014] Further preferably, the power supply monitoring module includes a wiring terminal, a backup power supply unit, a power supply control unit and a signal adjustment unit, the wiring terminal is respectively connected to the main control monitoring module, the bus connection module, the backup power supply unit and the power supply control unit, the backup power supply unit is respectively connected to the power supply control unit and the signal adjustment unit, the power supply control unit is respectively connected to the signal adjustment unit, the main control monitoring module and the bus connection module, and the signal adjustment unit is connected to the data storage module.

[0015] Further preferably, the backup power supply unit includes a backup power supply, a switching switch, a third resistor, a fourth resistor, a fifth resistor and a fifth capacitor, the common end of the third resistor and the fourth resistor are respectively connected to the wiring terminal and the power supply control unit, the other end of the third resistor is respectively connected to the wiring terminal, one end of the fifth capacitor, one end of the fifth resistor and the power supply control unit, the other end of the fourth resistor is respectively connected to the negative electrode of the backup power supply, the first end of the switching switch, the other end of the fifth resistor and the power supply control unit, the positive electrode of the backup power supply is connected to the wiring terminal, the second end of the switching switch is connected to the power supply control unit, and the third end of the switching switch is connected to air.

[0016] Further preferably, the power control unit includes a control chip, a first transistor, a fifth diode, a sixth diode, a seventh diode and a sixth capacitor, the first pin of the control chip is connected to the main control monitoring module, the second pin of the control chip is connected to the backup power supply unit, the third pin of the control chip is connected to the positive electrode of the fifth diode, the negative electrode of the fifth diode is respectively connected to the main control monitoring module, the negative electrode of the seventh diode and the collector of the first transistor, the fourth pin of the control chip is connected to the base of the first transistor, the emitter of the first transistor is respectively connected to the positive electrode of the sixth diode, the power module, the backup power supply unit and the fifth pin of the control chip, the common end of the sixth diode and the seventh diode is grounded through the sixth capacitor, and the sixth pin of the control chip is connected to the signal adjustment unit.

[0017] Further preferably, the signal adjustment unit includes a second transistor, an eighth diode, a seventh capacitor and a sixth resistor, the base of the second transistor is connected to the power control unit through the eighth diode, the emitter of the second transistor is respectively connected to one end of the seventh capacitor and the power module, the other end of the seventh capacitor is grounded, the collector of the second transistor is respectively connected to one end of the sixth resistor and the data storage module, and the other end of the sixth resistor is grounded.

[0018] More preferably, the data modification unit comprises an external terminal and a handheld programmer, and the external terminal is connected to the handheld programmer and the filtering and noise reduction unit respectively.

[0019] In a second aspect, the present application provides a power-off protection system, which includes a power-off protection circuit as described in any one of the first aspects.

[0020] The power-off protection circuit and the power-off protection system provided by the utility model have the following beneficial effects compared with the prior art:

[0021] (1) By setting a data input module, a main control monitoring module, a power monitoring module and a built-in backup power supply of the power monitoring module, when the main control monitoring module detects that the power module is powered off, the main control monitoring module controls the power monitoring module to switch the power supply end from the power module to the backup power supply. After the main control monitoring module completes the RAM write operation, it controls the power monitoring module to turn off the backup power supply and stop supplying power. At this time, the power supply time of the backup power supply can change with the time of the RAM write operation, so that the voltage of the power-off protection mode is relatively stable and the time length is controllable, so that even large data can be written;

[0022] (2) The handheld programmer is connected via terminal P9 and terminal P9 adopts RS485 communication, so that the TX differential transmitting end performs terminal matching on resistors R45 and R46, and a matching resistor is connected across the differential ports TX0+ and TX0- at both ends of the bus, thereby reducing the reflection and absorption noise caused by mismatch, and can effectively suppress noise interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1A schematic diagram of the framework of the power-off protection circuit provided by the utility model;

[0025] Figure 2 A circuit diagram of a data input module provided by the utility model;

[0026] Figure 3 The circuit schematic diagram of the main control monitoring module provided by the utility model;

[0027] Figure 4 A circuit schematic diagram of the power supply monitoring module provided by the utility model;

[0028] Figure 5 A circuit schematic diagram of a data storage module provided by the utility model;

[0029] Figure 6 This is a circuit schematic diagram of the bus connection module provided by the utility model.

[0030] Explanation of the accompanying drawings: 1. Data input module; 11. Data modification unit; 12. Filtering and noise reduction unit; 13. Differential drive unit; 2. Main control monitoring module; 3. Power supply monitoring module; 31. Wiring terminal; 32. Backup power supply unit; 33. Power supply control unit; 34. Signal adjustment unit; 4. Data storage module; 5. Bus connection module; 6. Power supply module. DETAILED DESCRIPTION

[0031] The following will be combined with the implementation of the utility model to clearly and completely describe the technical solutions in the implementation of the utility model. Obviously, the described implementation is only a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] The utility model discloses a power-off protection circuit, referring to Figure 1 The power-off protection circuit includes a data input module 1, a main control monitoring module 2, a power monitoring module 3, a data storage module 4, a bus connection module 5 and a power module 6, wherein:

[0033] The data input module 1 is electrically connected to the main control monitoring module 2 and the power supply module 6, respectively, and the data input module 1 is used to receive input signals. The data input module 1 includes a data modification unit 11, a filter noise reduction unit 12, and a differential drive unit 13. The data modification unit 11 is electrically connected to the filter noise reduction unit 12, the filter noise reduction unit 12 is electrically connected to the differential drive unit 13, and the differential drive unit 13 is electrically connected to the main control monitoring module 2. Among them, the data modification unit 11 includes an external terminal and a handheld programmer, and the external terminal is connected to the handheld programmer and the filter noise reduction unit 12, respectively.

[0034] In this embodiment, the filtering and noise reduction unit 12 includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a first diode, a second diode, a third diode and a fourth diode. The first common end and the second common end of the first capacitor and the second capacitor are both connected to the data modification unit 11 and the GND end, the first common end and the second common end of the third capacitor and the fourth capacitor are both connected to the data modification unit 11 and the GND end, one end of the first resistor is respectively connected to the third end of the data modification unit 11, the cathode of the first diode and the differential drive unit 13, the other end of the first resistor is respectively connected to the fourth end of the data modification unit 11, the cathode of the second diode and the differential drive unit 13, one end of the second resistor is respectively connected to the first end of the data modification unit 11, the cathode of the third diode and the differential drive unit 13, the other end of the second resistor is respectively connected to the second end of the data modification unit 11, the cathode of the fourth diode and the differential drive unit 13, and the anode of the first diode, the cathode of the second diode, the cathode of the third diode and the cathode of the fourth diode are grounded together.

[0035] The differential drive unit 13 includes a differential drive chip and a fifth capacitor. The first pin of the differential drive unit 13 is respectively connected to the power supply module 6 and one end of the fifth capacitor, and the other end of the fifth capacitor is grounded. The second pin and the third pin of the differential drive unit 13 are both connected to the main control monitoring module 2, the fourth pin of the differential drive unit 13 is grounded, and the fifth pin, the sixth pin, the seventh pin and the eighth pin of the differential drive unit 13 are all connected to the filtering and noise reduction unit 12.

[0036] For example, see Figure 2 , the specific circuit structure of the data input module 1 is described in detail below.

[0037] In a possible example, the data input module 1 includes a terminal P9, a terminal P7, a capacitor TZ1, a capacitor TZ2, a capacitor C8, a capacitor C11, a capacitor C12, a capacitor C13, a capacitor C14, a resistor R2, a resistor R3, a resistor R43, a resistor R44, a resistor R45, a resistor R46, a Zener diode Z1, a Zener diode Z2, a Zener diode Z3, a Zener diode Z4, and a differential driver and receiver pair U3. Among them, the terminal P9 corresponds to an external terminal, the capacitor C11 corresponds to a first capacitor, the capacitor C12 corresponds to a second capacitor, the capacitor C13 corresponds to a third capacitor, the capacitor C14 corresponds to a fourth capacitor, the resistor R2 corresponds to a first resistor, the resistor R3 corresponds to a second resistor, the Zener diode Z1 corresponds to a first diode, the Zener diode Z2 corresponds to a second diode, the Zener diode Z3 corresponds to a third diode, the Zener diode Z4 corresponds to a fourth diode, the differential driver and receiver pair U3 corresponds to the differential drive unit 13, and the capacitor C8 corresponds to a fifth capacitor.

[0038] The first pin of the terminal P9 is respectively connected to the sixth pin of the terminal P9, one end of the capacitor TZ2 and the third pin of the terminal P7, the second pin of the terminal P9 is respectively connected to the seventh pin of the terminal P9, one end of the capacitor TZ1 and the first pin of the terminal P7, the second pin of the terminal P7 is connected to the empty space, the third pin of the terminal P9 is connected to the empty space, the fourth pin of the terminal P9 is connected to the common end of the resistor R2 and the resistor R43, the fifth pin of the terminal P9 is connected to the common end of the resistor R3 and the resistor R45, the eighth pin of the terminal P9 is connected to the common end of the resistor R2 and the resistor R44, the ninth pin of the terminal P9 is connected to the common end of the resistor R3 and the resistor R46, the tenth pin and the eleventh pin of the terminal P9, the other end of the capacitor TZ1, the other end of the capacitor TZ2, the first common end and the second common end of the capacitor C11 and the capacitor C12, the first common end and the second common end of the capacitor C13 and the capacitor C14 are connected to the common end The common end of the resistor R43 and the Zener diode Z1 is connected to the eighth pin of the differential driver and receiver pair U3, the common end of the resistor R44 and the Zener diode Z2 is connected to the seventh pin of the differential driver and receiver pair U3, the common end of the resistor R45 and the Zener diode Z3 is connected to the fifth pin of the differential driver and receiver pair U3, the common end of the resistor R46 and the Zener diode Z4 is connected to the sixth pin of the differential driver and receiver pair U3, the positive electrode of the Zener diode Z1, the positive electrode of the Zener diode Z2, the positive electrode of the Zener diode Z3 and the positive electrode of the Zener diode Z4 are grounded together, the fourth pin of the differential driver and receiver pair U3 is grounded, the third pin and the second pin of the differential driver and receiver pair U3 are both connected to the main control monitoring module 2, the first pin of the differential driver and receiver pair U3 is respectively connected to the power module 6 and one end of the capacitor C8, and the other end of the capacitor C8 is grounded.

[0039] In one example, a handheld programmer is connected via terminal P9 and terminal P9 uses RS485 communication, so that the TX differential transmitter performs terminal matching with resistor R45 and resistor R46, and a 220Ω matching resistor is connected across the differential ports TX0+ and TX0- at both ends of the bus, thereby reducing the reflection and absorption noise caused by mismatching, and effectively suppressing noise interference. Since the matching resistor consumes a large current, it is not suitable for systems with strict power consumption constraints. This solution connects to the main control monitoring module 2 through the differential driver and receiver pair U3 and 100nf capacitor filtering, and provides a +5V power supply for the data input module 1, and powers the differential driver and receiver pair U3 after filtering through capacitors C1, C2, C3, C4 and C5.

[0040] The main control monitoring module 2 is electrically connected to the power monitoring module 3, the data storage module 4, the bus connection module 5 and the power module 6 respectively, and the main control monitoring module 2 is used to send a power switching signal to the power monitoring module 3. The circuit diagram of the main control monitoring module 2 is shown in FIG. Figure 3 As shown, the main control monitoring module 2 adopts a 32-bit microcontroller of model MC68332A.

[0041] The power monitoring module 3 is electrically connected to the data storage module 4, the bus connection module 5 and the power module 6 respectively. The power monitoring module 3 has a built-in backup power supply. The power monitoring module 3 is used to receive a power switching signal and switch the power module 6 to the backup power supply.

[0042] In this embodiment, the power supply monitoring module 3 includes a wiring terminal 31, a backup power supply unit 32, a power supply control unit 33 and a signal adjustment unit 34. The wiring terminal 31 is respectively connected to the main control monitoring module 2, the bus connection module 5, the backup power supply unit 32 and the power supply control unit 33. The backup power supply unit 32 is respectively connected to the power supply control unit 33 and the signal adjustment unit 34. The power supply control unit 33 is respectively connected to the signal adjustment unit 34, the main control monitoring module 2 and the bus connection module 5. The signal adjustment unit 34 is connected to the data storage module 4.

[0043] The backup power supply unit 32 includes a backup power supply, a switching switch, a third resistor, a fourth resistor, a fifth resistor and a fifth capacitor. The common end of the third resistor and the fourth resistor are respectively connected to the wiring terminal 31 and the power control unit 33, the other end of the third resistor is respectively connected to the wiring terminal 31, one end of the fifth capacitor, one end of the fifth resistor and the power control unit 33, the other end of the fourth resistor is grounded, the other end of the fifth capacitor is respectively connected to the negative electrode of the backup power supply, the first end of the switching switch, the other end of the fifth resistor and the power control unit 33, the positive electrode of the backup power supply is connected to the wiring terminal 31, the second end of the switching switch is connected to the power control unit 33, and the third end of the switching switch is connected to air.

[0044] The power control unit 33 includes a control chip, a first transistor, a fifth diode, a sixth diode, a seventh diode and a sixth capacitor. The first pin of the control chip is connected to the main control monitoring module 2, the second pin of the control chip is connected to the backup power supply unit 32, the third pin of the control chip is connected to the positive electrode of the fifth diode, the negative electrode of the fifth diode is respectively connected to the main control monitoring module 2, the negative electrode of the seventh diode and the collector of the first transistor, the fourth pin of the control chip is connected to the base of the first transistor, the emitter of the first transistor is respectively connected to the positive electrode of the sixth diode, the power module 6 backup power supply unit 32 and the fifth pin of the control chip, the common end of the sixth diode and the seventh diode is grounded through the sixth capacitor, and the sixth pin of the control chip is connected to the signal adjustment unit 34.

[0045] The signal adjustment unit 34 includes a second transistor, an eighth diode, a seventh capacitor and a sixth resistor. The base of the second transistor is connected to the power control unit 33 through the eighth diode, the emitter of the second transistor is respectively connected to one end of the seventh capacitor and the power module 6, and the other end of the seventh capacitor is grounded. The collector of the second transistor is respectively connected to one end of the sixth resistor and the data storage module 4, and the other end of the sixth resistor is grounded.

[0046] For example, see Figure 4 , the specific circuit structure of the power supply monitoring module 3 is described in detail below.

[0047] In a possible example, the power monitoring module 3 includes a terminal JP3, a resistor R1, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R40, a resistor R42, a switch SW1, a battery BT1, a capacitor C6, a capacitor C7, a capacitor C9, a capacitor C10, a capacitor C15, a capacitor C16, a diode D1, a diode D2, a diode D3, a diode D4, a transistor Q1, a transistor Q2, a terminal JP10, a terminal JP11 and a controller U4. Among them, terminal JP3 corresponds to terminal 31, resistor R5 corresponds to the third resistor, resistor R6 corresponds to the fourth resistor, capacitor C9 corresponds to the fifth capacitor, battery BT1 corresponds to the backup power supply, switch SW1 corresponds to the switching switch, resistor R42 corresponds to the fifth resistor, controller U4 corresponds to the control chip, transistor Q1 corresponds to the first transistor, diode D3 corresponds to the fifth diode, diode D1 corresponds to the sixth diode, diode D2 corresponds to the seventh diode, diode D4 corresponds to the eighth diode, capacitor C10 corresponds to the sixth capacitor, transistor Q1 corresponds to the first transistor, transistor Q2 corresponds to the second transistor, resistor R7 corresponds to the sixth resistor, and capacitor C15 corresponds to the seventh capacitor.

[0048] The first pin of terminal JP3 is respectively connected to the main control monitoring module 2 and one end of the resistor R40, the other end of the resistor R40 is grounded, the second pin of terminal JP3 is connected to the air, the third pin of terminal JP3 is connected to the bus connection module 5, the fourth pin of terminal JP3 is connected to the WDI pin of the controller U4, the fifth pin of terminal JP3 is respectively connected to the common end of resistors R5 and R6 and the PFI pin of the controller U4, the sixth pin of terminal JP3 is respectively connected to one end of capacitor C9, the other end of resistor R5, one end of resistor R42 and the VBAT pin of the controller U4, the seventh pin of terminal JP3 is connected to the positive electrode of battery BT1, the eighth pin of terminal JP3 is connected to the main control monitoring module 2, and the ninth pin of terminal JP3 is respectively connected to the The pin is connected to the main control monitoring module 2, the tenth pin of the terminal JP3 is grounded, the other end of the resistor R6 is grounded, the other end of the capacitor C9, the negative electrode of the battery BT1, the first end of the switch SW1, the other end of the resistor R42, the GND pin of the controller U4 and one end of the capacitor C6 are grounded, the second end of the switch SW1 is connected to the GND pin of the controller U4 The other end of the capacitor C6 is connected to the VCC pin of the controller U4, the power module, the emitter of the transistor Q1 and the positive electrode of the diode D1 respectively, the BACKUP pin of the controller U4 is connected to the main control monitoring module 2, and the The pins are connected to the bus connection module 5 and one end of the terminal JP10 respectively, the base of the transistor Q1 is connected to the BATTON pin of the controller U4 through the resistor R4, the common end of the diode D1 and the diode D2 is grounded through the resistor R1 and the capacitor C10 in turn, the collector of the transistor Q1 is connected to the cathode of the diode D2, the cathode of the diode D3 and the main control monitoring module 2 respectively, the VOUT pin of the controller U4 is connected to one end of the capacitor C7 and the anode of the diode D3 respectively, the other end of the capacitor C7 is grounded, and the Pin is empty, controller U4 The pin is connected to one end of terminal JP11, and the controller U4 The pin is connected to the main control monitoring module 2, the RESET pin of the controller U4 is connected to the cathode of the diode D4, and the The pin is connected to the bus connection module 5, the other end of the terminal JP10 and the other end of the terminal JP11 are commonly connected to the data storage module 4, the anode of the diode D4 is connected to the base of the transistor Q2, the emitter of the transistor Q2 is respectively connected to one end of the capacitor C15, one end of the capacitor C16 and the power module, the other end of the capacitor C15 and the other end of the capacitor C16 are both grounded, the collector of the transistor Q2 is respectively connected to one end of the resistor R7 and the data storage module 4, and the other end of the resistor R7 is grounded.

[0049] In one example, the controller U4 uses a microprocessor of model LTC1235. The microprocessor LTC1235 provides complete power monitoring and battery control functions for the power-off protection circuit, and can be used for microprocessor reset, battery backup, RAM write protection, power failure warning, and watchdog timing. When the power supply is out of tolerance, the reset output is forced into an active state, and the microprocessor LTC1235 enables the output to write-protect the external memory. The RESET output is guaranteed to maintain a logic low level when the VCC pin is as low as 1V, and the input can be reset by a debounce button reset through an external reset control. The microprocessor LTC1235 supplies power to the active CMOS RAM through a charge pump NMOS power switch to achieve low voltage drop and low supply current. When the power module 6 is lost, the power-off protection circuit can be connected to the auxiliary power supply of the battery input pin to provide backup power for the RAM. The power-off protection circuit can be programmed through a μP signal to achieve backup or non-backup of the RAM, which prolongs the battery life and can always save the RAM data when the power module 6 is powered off. At the same time, in order to issue an early warning of an impending power failure, the microprocessor LTC1235 provides an internal comparator with a user-defined threshold. In addition, an internal watchdog timer is provided. When the watchdog input does not switch before the timeout period, the timer forces the reset pin to enter an active state. Terminal JP3 can select battery power supply through a jumper cap to ensure that data will not be lost in the event of a sudden power failure, and the system can save important data. Switch SW1 performs an external manual reset, and different reset functions can be performed by different pressing times.

[0050] In this embodiment, the data storage module 4 is electrically connected to the bus connection module 5 and the power module 6 respectively, and the data storage module 4 is used to store input signals. Figure 5 As shown, the data storage module 4 includes four parallel-connected Flash memories, and the Flash memory can be a Flash memory of model 29F040.

[0051] In this embodiment, the bus connection module 5 is electrically connected to the power supply module 6. Figure 6 As shown, it is a circuit schematic diagram of the bus connection module 5 provided in this application.

[0052] The utility model also provides a power-off protection system, which includes each of the power-off protection circuits described above.

[0053] It should be noted that, in the present invention, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A power-off protection circuit, characterized in that: It comprises a data input module (1), a main control monitoring module (2), a power supply monitoring module (3), a data storage module (4), a bus connection module (5) and a power supply module (6), wherein: The data input module (1) is electrically connected to the main control monitoring module (2) and the power supply module (6) respectively, and the data input module (1) is used to receive input signals; The main control monitoring module (2) is electrically connected to the power monitoring module (3), the data storage module (4), the bus connection module (5) and the power module (6) respectively, and the main control monitoring module (2) is used to send a power switching signal to the power monitoring module (3); The power monitoring module (3) is electrically connected to the data storage module (4), the bus connection module (5) and the power module (6) respectively; the power monitoring module (3) is equipped with a backup power supply; the power monitoring module (3) is used to receive the power switching signal and switch the power module (6) to the backup power supply; The data storage module (4) is electrically connected to the bus connection module (5) and the power supply module (6) respectively, and the data storage module (4) is used to store the input signal; The bus connection module (5) is electrically connected to the power supply module (6).

2. The power-off protection circuit according to claim 1, characterized in that: The data input module (1) comprises a data modification unit (11), a filtering and noise reduction unit (12) and a differential drive unit (13); the data modification unit (11) is electrically connected to the filtering and noise reduction unit (12); the filtering and noise reduction unit (12) is electrically connected to the differential drive unit (13); and the differential drive unit (13) is electrically connected to the main control monitoring module (2).

3. The power-off protection circuit according to claim 2, characterized in that: The filtering and noise reduction unit (12) comprises a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first resistor, a second resistor, a first diode, a second diode, a third diode and a fourth diode; the first common end and the second common end of the first capacitor and the second capacitor are both connected to the data modification unit (11) and a GND terminal; the first common end and the second common end of the third capacitor and the fourth capacitor are both connected to the data modification unit (11) and a GND terminal; one end of the first resistor is respectively connected to the third end of the data modification unit (11), the cathode of the first diode and the differential driving unit (13); The other end of the first resistor is respectively connected to the fourth end of the data modification unit (11), the cathode of the second diode and the differential drive unit (13); one end of the second resistor is respectively connected to the first end of the data modification unit (11), the cathode of the third diode and the differential drive unit (13); the other end of the second resistor is respectively connected to the second end of the data modification unit (11), the cathode of the fourth diode and the differential drive unit (13); the anode of the first diode, the anode of the second diode, the anode of the third diode and the anode of the fourth diode are commonly grounded.

4. The power-off protection circuit according to claim 2, characterized in that: The differential drive unit (13) comprises a differential drive chip and a fifth capacitor; a first pin of the differential drive unit (13) is respectively connected to the power module (6) and one end of the fifth capacitor; the other end of the fifth capacitor is grounded; a second pin and a third pin of the differential drive unit (13) are both connected to the main control monitoring module (2); a fourth pin of the differential drive unit (13) is grounded; and a fifth pin, a sixth pin, a seventh pin and an eighth pin of the differential drive unit (13) are all connected to the filtering and noise reduction unit (12).

5. The power-off protection circuit according to claim 1, characterized in that: The power supply monitoring module (3) comprises a wiring terminal (31), a backup power supply unit (32), a power supply control unit (33) and a signal adjustment unit (34); the wiring terminal (31) is respectively connected to the main control monitoring module (2), the bus connection module (5), the backup power supply unit (32) and the power supply control unit (33); the backup power supply unit (32) is respectively connected to the power supply control unit (33) and the signal adjustment unit (34); the power supply control unit (33) is respectively connected to the signal adjustment unit (34), the main control monitoring module (2) and the bus connection module (5); and the signal adjustment unit (34) is connected to the data storage module (4).

6. The power-off protection circuit according to claim 5, characterized in that: The backup power supply unit (32) comprises a backup power supply, a switching switch, a third resistor, a fourth resistor, a fifth resistor and a fifth capacitor. The common end of the third resistor and the fourth resistor is respectively connected to the wiring terminal (31) and the power control unit (33). The other end of the third resistor is respectively connected to the wiring terminal (31), one end of the fifth capacitor, one end of the fifth resistor and the power control unit (33). The other end of the fourth resistor is grounded. The other end of the fifth capacitor is respectively connected to the negative electrode of the backup power supply, the first end of the switching switch, the other end of the fifth resistor and the power control unit (33). The positive electrode of the backup power supply is connected to the wiring terminal (31). The second end of the switching switch is connected to the power control unit (33). The third end of the switching switch is connected to air.

7. The power-off protection circuit according to claim 5, characterized in that: The power control unit (33) comprises a control chip, a first transistor, a fifth diode, a sixth diode, a seventh diode and a sixth capacitor, wherein the first pin of the control chip is connected to the main control monitoring module (2), the second pin of the control chip is connected to the backup power supply unit (32), the third pin of the control chip is connected to the positive electrode of the fifth diode, the negative electrode of the fifth diode is respectively connected to the main control monitoring module (2), the negative electrode of the seventh diode and the collector of the first transistor, the fourth pin of the control chip is connected to the base of the first transistor, the emitter of the first transistor is respectively connected to the positive electrode of the sixth diode, the power module (6), the backup power supply unit (32) and the fifth pin of the control chip, the common end of the sixth diode and the seventh diode is grounded through the sixth capacitor, and the sixth pin of the control chip is connected to the signal adjustment unit (34).

8. The power-off protection circuit according to claim 5, characterized in that: The signal adjustment unit (34) comprises a second triode, an eighth diode, a seventh capacitor and a sixth resistor, the base of the second triode is connected to the power control unit (33) via the eighth diode, the emitter of the second triode is respectively connected to one end of the seventh capacitor and the power module (6), the other end of the seventh capacitor is grounded, the collector of the second triode is respectively connected to one end of the sixth resistor and the data storage module (4), and the other end of the sixth resistor is grounded.

9. The power-off protection circuit according to claim 2, characterized in that: The data modification unit (11) comprises an external terminal and a handheld programmer, and the external terminal is connected to the handheld programmer and the filtering and noise reduction unit (12) respectively.

10. A power-off protection system, characterized in that: The invention comprises a power-off protection circuit as claimed in any one of claims 1 to 9.

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