CN115632472A - Power supply switching circuit of main control unit and control method thereof - Google Patents

Power supply switching circuit of main control unit and control method thereof Download PDF

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Publication number
CN115632472A
CN115632472A CN202211287808.3A CN202211287808A CN115632472A CN 115632472 A CN115632472 A CN 115632472A CN 202211287808 A CN202211287808 A CN 202211287808A CN 115632472 A CN115632472 A CN 115632472A
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CN
China
Prior art keywords
power supply
main control
control unit
lithium battery
charging
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Pending
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CN202211287808.3A
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Chinese (zh)
Inventor
刘苏成
王国俊
李杨
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Nanjing Apaitek Technology Co ltd
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Nanjing Apaitek Technology Co ltd
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Priority to CN202211287808.3A priority Critical patent/CN115632472A/en
Publication of CN115632472A publication Critical patent/CN115632472A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00302—Overcharge protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00306—Overdischarge protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems

Abstract

The invention discloses a power supply switching circuit of a main control unit and a control method thereof, which are used for controlling the switching of a power supply of the main control unit into standby power after the power failure of the main control unit; the lithium battery charging circuit comprises a main control unit power supply switching circuit, a lithium battery and a charging circuit thereof; the MOS tube is arranged in the power supply switching circuit of the main control unit, when the voltage of the battery is detected to be lower than a certain value, the charging function is entered when the voltage is normally lower than 3.5V, and the MOS tube is controlled to be conducted to charge. When the voltage is higher than 4.2V, the battery can be ensured to be in a saturated full-charge state, the battery charging function can be terminated after a period of time, the MOS tube is controlled to be turned off, and the charging is closed; the main control unit power supply switching circuit adopts two MOS butt joints to form interconnection, and ensures that the current of the output end cannot flow back to the lithium battery end. The invention can effectively solve the problem that the main control unit can normally supply power for sudden power failure or fault power failure of system equipment, processes the real-time acquisition and storage of data and transmits the data to the upper control center platform through communication.

Description

Power supply switching circuit of main control unit and control method thereof
Technical Field
The invention relates to the technical field of power electronics, in particular to a power supply switching circuit of a main control unit and a control method thereof.
Background
With the continuous development of power electronic technology, on one hand, the requirements on the instantaneity and storability of important data acquisition of system equipment are higher and higher, and the key data acquisition and reanalysis capacity provides an important basis for further improving the system stability; on the other hand, the protection requirements for system equipment, especially for the vulnerable core devices such as IGBT, siC and other key devices, are also more and more demanding. The timely response protection mechanisms of the real-time data acquisition, storage and devices are particularly important before and after sudden power failure of equipment or power failure of equipment. The device may involve various external parameters and internal parameter changes at the moment of power failure during operation, and the real-time state of the operation control drive is the same, so that a response mechanism is difficult to be pertinently made for protection of the device or even if the design cost of protection is increased, the protection of various devices is difficult to be perfected. Aiming at the requirements, more and more manufacturers can increase a standby power supply to supply power to the main control unit, the standby power supply is switched to continue to supply power to the main control unit immediately after system equipment is powered off, the main control unit can operate normally, data are collected in real time and stored, and after the power off of the equipment is detected, the main control unit sends a protection mechanism to turn off key input and output signals of the relevant equipment, so that the abnormal damage of the equipment and key devices is prevented. The first scheme is that a backup power supply UPS, namely an uninterruptible power supply with an energy storage device, is directly used for providing an uninterrupted power supply for partial equipment with higher requirements on the stability of the power supply; the other type is that a button cell is placed in the main control processor, and relevant important parameters and data information can be stored after the system equipment is powered off.
The two solutions, although possible, have several disadvantages: 1) The UPS power supply has larger volume and is not suitable for being placed due to the limited space of the equipment module; the cost is high even if small capacity is selected; the response time of the UPS is longer, and the UPS is not suitable for main control equipment which is sensitive to charge and discharge. 2) The button battery is adopted, so that related real-time data can be stored, but the button battery is not easy to maintain, and cannot confirm whether the power is normally supplied or not, so that a detection means is lost; and then only data processing can be performed, the normal communication function of the main control unit cannot be ensured, communication with an upper computer cannot be continued to realize data interaction, and meanwhile, the control function of the main control is lost, so that the main control state is in a random state, and timely protective measure response cannot be performed on equipment.
Disclosure of Invention
1. The technical problem to be solved is as follows:
in view of the above technical problems, the present invention provides a power supply switching circuit for a main control unit, which is capable of switching power supplies in a nanosecond hardware response after a power failure of the main control unit, so that the main control unit supplies power normally and stably, and realizes real-time data acquisition and storage functions, normal communication functions, and timely processing of response measures after a power failure of system equipment. The circuit is convenient for effectively protecting the damage faults of equipment and key devices, can timely protect the working abnormal states of other external load equipment, and further improves the running reliability of the equipment in the whole circuit network.
2. The technical scheme is as follows:
a power supply switching circuit of a main control unit is used for controlling the power supply of the main control unit to be switched into a standby power supply after the power failure of the main control unit; the method is characterized in that: the lithium battery charging circuit comprises a main control unit power supply switching circuit, a lithium battery and a charging circuit thereof; the main control unit power supply switching circuit is connected with the lithium battery to control whether the lithium battery is used for supplying power to the main control unit;
the lithium battery and the charging circuit thereof comprise a control circuit and a charging circuit; the trigger signal CL _ BT of the control circuit is sent out by a corresponding pin of a control chip of the main control unit; the trigger signal CL _ BT is connected to the base electrode of the triode Q2 after being connected to the current limiting resistor R5 through a circuit; the emitter of the triode Q2 is grounded AGND, and the collector is connected to the gate of the control MOS tube Q1; a resistor R1 is connected in parallel between the source electrode and the gate electrode of the MOS transistor Q1; the source electrode of the MOS tube Q1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to a power supply; the drain electrode of the MOS tube Q1 is connected to a power supply pin of the charging chip U1; a power supply pin of a charging chip U1 of the charging circuit is connected with a bypass filter capacitor C1 in series and then grounded; a chip charging current control pin of the charging chip U1 is connected with a resistor R2 in series and then grounded; a charging output pin of the charging chip U1 is connected to the lithium battery BT1 for charging management; a bypass filter capacitor C2 is connected in parallel between the anode and the cathode of the lithium battery BT 1; the positive electrode of the lithium battery BT1 is connected to a resistor R3, then connected to a resistor R4 and finally grounded AGND; the resistors R3 and R4 form voltage division, a circuit connected between the resistors R3 and R4 forms a net point AD _ BT, and the AD _ BT is connected to a sampling port of a control chip of the main control unit;
the drain electrode of an MOS (metal oxide semiconductor) tube Q3 of the power supply switching circuit of the main control unit is connected to the output voltage of the lithium battery BT 1; the source electrode of the MOS tube Q3 is connected with the source electrode of the MOS tube Q4, and the two tubes Q3 and Q4 form a butt joint method; the gates of the Q3 and Q4 tubes are shorted and then are grounded after being connected with the resistor R6 in series; the short-circuit position of the gate poles of the Q3 and the Q4 is connected with the cathode of a diode D3, and the anode of the D3 is connected with a power supply; the drain electrode output of the MOS tube Q4 is connected to a power supply MVCC of the main control unit; the drain electrode of the MOS transistor Q4 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the power supply.
Further, the model of the charging chip U1 is BL4054.
Further, the power supply is 5.3V.
A switching method of a power supply switching circuit of a main control unit comprises the following steps:
controlling the charge and discharge of the lithium battery: the sampling voltage of a sampling port of a control chip of the main control unit is reduced to a preset voltage value, a control signal CL _ BT sent by the control chip of the main control unit is at a high level, an MOS (metal oxide semiconductor) tube is conducted, and a lithium battery BT1 is charged; when the sampling voltage reaches a preset value, continuing to charge for a period of time and the voltage value is unchanged, changing the control signal CL _ BT into a low level, stopping the MOS transistor, and stopping charging the lithium battery BT 1;
the main control unit supplies power and switches over the control: when the power supply exists, the diode D2 is conducted, the gate poles of the MOS transistors Q3 and Q4 are at high level, the transistor Q4 is cut off, and the loop is not conducted, so that the power supply participates in power supply in the state, and the power supply of the lithium battery is in a cut-off state; when the power supply is suddenly lost or fails, the diode D2 is cut off, the gate poles of the MOS tubes Q3 and Q4 are at low level, the MOS tubes Q3 and Q4 are in a conducting state, and the lithium battery participates in power supply at the moment, so that the fast power supply switching of a hardware circuit is realized, and the normal power supply ground of the main control power supply is continuously kept.
3. Has the beneficial effects that:
(1) The lithium battery charging circuit not only ensures that the normal voltage of the lithium battery is stored, prevents the failure of the lithium battery caused by long-time consumption, but also satisfies the condition that the lithium battery cannot be in a charging state for a long time all the time, and the lithium battery can be damaged by overshoot and overdischarge, thereby reducing the service life. Controlling charging conduction and disconnection through an MOS (metal oxide semiconductor) tube; the charging chip BL4054 is used for realizing the charging of the lithium battery and protecting the lithium battery, so that the service life of the lithium battery is prolonged. And such a set of charging circuit device of this scheme is very little, and the cost is also extremely low, is applicable to the charging control circuit of master control unit very much.
(2) The main control unit power supply switching circuit in this scheme, simple structure adopts two P passageway MOS pipe butt joints, forms the interconnection, ensures that output end current can not flow backwards to the lithium cell end. The circuit also has the function of realizing circuit power supply switching by using a single diode and a main control unit power supply in parallel, but the conduction voltage drop of the diode is generally higher and is about 0.7V. For the voltage of the power supply of the lithium battery, the service efficiency of the lithium battery is greatly reduced, and the working time is reduced. The on-resistance of the MOS tube is generally within hundred milliohms, and the loss voltage is very low and is almost ignored. The MOS tube is used, the anti-reverse-flow function of the diode is also realized, the loss can be reduced, and the power supply use efficiency of the lithium battery is greatly improved.
Drawings
FIG. 1 is a circuit diagram of a lithium battery charging circuit according to an embodiment;
fig. 2 is a circuit diagram of a master unit switching circuit according to an embodiment.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
As shown in fig. 1 and 2, a power supply switching circuit of a main control unit is used for switching between a power supply and a standby power supply after a power failure of the main control unit of a system device; the lithium battery charging circuit comprises a main control unit power supply switching circuit, a lithium battery and a charging circuit thereof; the main control unit power supply switching circuit is connected with the lithium battery and controls whether the lithium battery is used for supplying power to the system equipment.
The specific embodiment is as follows:
fig. 1 and 2 are specific circuit diagrams and parameters of the present embodiment; in this embodiment, the power supply of the main control unit takes 5.3V as an example, and 5.3V is the voltage of the most common control unit; the input power of the equipment in the system is mostly 24V, so the equipment is switched to a 5V power supply in the design for communication and control. The stand-by power supply adopts the lithium cell as stand-by power supply BTV, and when the 5.3V power outage back, BTV stands the horse and participates in the power supply of main control unit.
Fig. 1 shows a lithium battery charging circuit, which is composed of a control circuit and a charging circuit. The control process specifically comprises the following steps:
1) The net point CL _ BT in the circuit is a trigger signal of the charging control circuit, can be sent out by a control chip pin of the main control unit, is connected to the base electrode of the triode Q2 through a current-limiting resistor R5, the emitting electrode of the Q2 is grounded AGND, and the collecting electrode is connected to the gate electrode of the control MOS tube Q1. When the control signal CL _ BT is at high level, the triode Q2 is conducted, the collector electrode is pulled down to be at low level, when the CL _ BT is at low level, the triode Q2 is cut off, the collector electrode is pulled up to be at high level through the connecting resistor R1, the R1 is connected to the cathode of the anti-reflection diode D1, the anode of the D1 is connected with the power supply 5.3V, the voltage drop of the diode D1 and the D1 is about 0.3V, and therefore the voltage of the resistor R1 is 5V. The negative electrode of the D1 is simultaneously connected to the source electrode of the MOS tube, the MOS tube is switched on and off by the voltage change between the negative electrode and the gate electrode, when the voltage is 0V, the MOS tube is switched off, and when the voltage is 5V, the MOS tube is switched on. The drain electrode of the MOS tube is connected to a power supply pin of a charging chip in the charging circuit. Summarizing, when the control signal CL _ BT is at high level, the MOS transistor is turned on to realize the charging function, and when the control signal CL _ BT is at low level, the MOS transistor is turned off to terminate the charging function.
2) A battery management chip U1 is selected in the charging circuit, the model is BL4054, 4 pins of the U1 are power pins, the drain electrode of the MOS tube Q1 is connected, and the C1 is a bypass filter capacitor of the management chip U1. U1 has 5 pins connected to R2 and then to ground, 5 pins are chip charging current control pins, and the calculated charging current IBAT = (VPROG/R2) × 1000 = (1V/1.65K) × 1000 = 600MA. Therefore, when the charge control resistor R2 of the circuit takes on a value of 1.65, the charging current for the lithium battery is 600MA. Pin 1 of U1 is floating, and this pin is mainly used as the switch output of the charging state, and may not be connected. And the pin 2 of the U1 is a power supply ground pin and is connected with the AGND. And the pin 3 of the U1 is a charging output pin and is connected with a lithium battery BT1 for charging management of the lithium battery. And C2 is a bypass filter capacitor of the lithium battery BT 1. The positive electrode of BT1 is connected with a resistor R3, then connected with a resistor R4, and finally grounded AGND. The resistors R3 and R4 form a voltage division connection to a net point AD _ BT, the AD _ BT is connected to a sampling port of a control chip of the main control unit, and the resistance values of the resistors R3 and R4 are selected to be as large as possible under the permission of sampling current, so that the loss of the battery can be reduced. The highest voltage division value cannot exceed the maximum sampling voltage of the control chip of the main control unit. When the voltage value is reduced to a certain value, the charging function is started, and the net point CL _ BT is set high. And when the lithium battery is fully charged, the net point CL _ BT is pulled down, and the charging function is turned off.
Fig. 2 shows a power supply switching circuit of the main control unit, which is composed of MOS transistor circuits.
1) The net point BTV in the circuit is the lithium battery supply voltage. The net point BTV is connected to the drain electrode of the MOS tube Q3, the source electrode of the Q3 is connected with the source electrode of the MOS tube Q4, the two tubes form a butt joint method, the gate electrode short circuits of the two tubes are grounded through a resistor R6, the D3 tube is connected to a power supply 5.3V through reverse connection prevention, the gate electrode of the MOS tube is controlled through the existence of 5.3V main power, and the drain electrode output of the Q4 is connected to the net point MVCC which is the power supply of the main control unit.
2) A D2 anti-reverse diode in the circuit and MOS transistors Q3 and Q4 form a dual-power supply switching circuit, when a main power supply 5.3V exists, the diode D2 is conducted, gate poles of the MOS transistors Q3 and Q4 are in a high level, the Q4 transistor is cut off, a loop is not conducted, therefore, in the state, the main power supply 5.3V participates in power supply, the lithium battery is in a cut-off state, when the main power supply 5.3V is suddenly powered off or fails to supply power, the D2 transistor is cut off, the gate poles of the MOS transistors Q3 and Q4 are in a low level, and the Q3 and Q4 are both in a conducting state. Therefore, the lithium battery participates in power supply in the state, the rapid power supply switching of the hardware circuit is formed, and the normal power supply of the main control power supply is continuously kept.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (4)

1. A power supply switching circuit of a main control unit is used for controlling the power supply of the main control unit to be switched into a standby power supply after the power failure of the main control unit; the method is characterized in that: the lithium battery charging circuit comprises a main control unit power supply switching circuit, a lithium battery and a charging circuit thereof; the main control unit power supply switching circuit is connected with the lithium battery to control whether the lithium battery is used for supplying power to the main control unit;
the lithium battery and the charging circuit thereof comprise a control circuit and a charging circuit; the trigger signal CL _ BT of the control circuit is sent out by a corresponding pin of a control chip of the main control unit; the trigger signal CL _ BT is connected to the base electrode of the triode Q2 after being connected to the current limiting resistor R5 through a circuit; an emitter of the triode Q2 is grounded AGND, and a collector of the triode Q2 is connected to a gate pole of the control MOS tube Q1; a resistor R1 is connected in parallel between the source electrode and the gate electrode of the MOS transistor Q1; the source electrode of the MOS tube Q1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to a power supply; the drain electrode of the MOS tube Q1 is connected to a power supply pin of the charging chip U1; a power supply pin of a charging chip U1 of the charging circuit is connected with a bypass filter capacitor C1 in series and then grounded; a chip charging current control pin of the charging chip U1 is connected with a resistor R2 in series and then grounded; a charging output pin of the charging chip U1 is connected to the lithium battery BT1 for charging management; a bypass filter capacitor C2 is connected in parallel between the anode and the cathode of the lithium battery BT 1; the positive electrode of the lithium battery BT1 is connected to the resistor R3, then connected to the resistor R4 and finally grounded AGND; the resistors R3 and R4 form voltage division, a circuit connected between the resistors R3 and R4 forms a net point AD _ BT, and the AD _ BT is connected to a sampling port of a control chip of the main control unit;
the drain electrode of an MOS (metal oxide semiconductor) tube Q3 of the power supply switching circuit of the main control unit is connected to the output voltage of the lithium battery BT 1; the source electrode of the MOS tube Q3 is connected with the source electrode of the MOS tube Q4, and the two tubes Q3 and Q4 form a butt joint method; the gates of the Q3 and Q4 tubes are shorted and then are connected with the resistor R6 in series and then are grounded; the short-circuit position of the gate poles of the Q3 and the Q4 is connected with the cathode of a diode D3, and the anode of the D3 is connected with a power supply; the drain electrode output of the MOS tube Q4 is connected to a power supply MVCC of the main control unit; the drain electrode of the MOS transistor Q4 is connected to the cathode of the diode D2, and the anode of the diode D2 is connected to the power supply.
2. The power supply switching circuit of claim 1, wherein: the model of the charging chip U1 is BL4054.
3. The power supply switching circuit of claim 1, wherein: the power supply is 5.3V.
4. A control method of a power supply switching circuit of a main control unit is characterized in that: the method comprises the following steps:
controlling the charge and discharge of the lithium battery: the sampling voltage of a sampling port of a control chip of the main control unit is reduced to a preset voltage value, a control signal CL _ BT sent by the control chip of the main control unit is at a high level, an MOS (metal oxide semiconductor) tube is conducted, and a lithium battery BT1 is charged; when the sampling voltage reaches a preset value, continuing to charge for a period of time and the voltage value is unchanged, changing the control signal CL _ BT into a low level, stopping the MOS transistor, and stopping charging the lithium battery BT 1;
the main control unit supplies power and switches over the control: when the power supply exists, the diode D2 is conducted, the gate poles of the MOS transistors Q3 and Q4 are at high level, the transistor Q4 is cut off, and the loop is not conducted, so that the power supply participates in power supply in the state, and the power supply of the lithium battery is in a cut-off state; when the power supply is suddenly lost or fails, the diode D2 is cut off, the gate poles of the MOS transistors Q3 and Q4 are at low level, the MOS transistors Q3 and Q4 are in a conducting state, and the lithium battery participates in power supply at the moment, so that the fast power supply switching of the hardware circuit is realized, and the normal power supply of the main control power supply is continuously maintained.
CN202211287808.3A 2022-10-20 2022-10-20 Power supply switching circuit of main control unit and control method thereof Pending CN115632472A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211287808.3A CN115632472A (en) 2022-10-20 2022-10-20 Power supply switching circuit of main control unit and control method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211287808.3A CN115632472A (en) 2022-10-20 2022-10-20 Power supply switching circuit of main control unit and control method thereof

Publications (1)

Publication Number Publication Date
CN115632472A true CN115632472A (en) 2023-01-20

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211287808.3A Pending CN115632472A (en) 2022-10-20 2022-10-20 Power supply switching circuit of main control unit and control method thereof

Country Status (1)

Country Link
CN (1) CN115632472A (en)

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