Main and standby power management circuit for preventing over discharge of battery

Abstract

The utility model relates to a main / standby power management circuit for preventing over-discharge of a battery. The main / standby power management circuit comprises a power supply protection circuit, a system control circuit, a first resistor and a current type switch, the power supply protection circuit comprises a voltage type switch, one end of the voltage type switch is electrically connected with the battery, and the other end of the voltage type switch is electrically connected with the system control circuit; the system control circuit is also electrically connected with the current type switch; the current type switch is also electrically connected with the voltage type switch; one end of the first resistor is electrically connected between the battery and the voltage type switch, and the other end of the first resistor is electrically connected between the current type switch and the voltage type switch; the system control circuit is used for controlling the current type switch to be switched off or switched on, and if the current type switch is switched off or switched on, the voltage type switch is correspondingly switched off or switched on; power supply of the battery and a rear-end system can be cut off during under-voltage protection of the battery, the protection circuit does not consume current, the battery does not consume electricity to the outside any more, and over-discharge damage of the battery due to long-time non-charging after under-voltage protection is effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of battery power supply, and more particularly to a main and backup power management circuit for preventing battery over-discharge. Background Art

[0002] In the host of security protection systems such as fire alarm control systems and fire door monitoring systems, when the main power supply 220V is cut off, the system will automatically switch to the backup battery power supply, so that the system can continue to work for a certain period of time; when the battery works to the point that its own power can no longer maintain the system operation, the battery will be powered off for protection until the next time the main power supply 220V is turned on to charge the battery.

[0003] In actual applications, the battery may power down when its own charge can no longer sustain system operation. At this point, the battery charge is extremely low. If no human intervention disconnects the power line between the battery and the system, the battery will continue to discharge into the protection circuit, enabling the circuit to function normally and provide protection. The protection circuit can be thought of as a switch. When the battery reaches undervoltage protection, the switch opens. Maintaining the switch requires continuous battery power, resulting in a continuous current loss to the system ground. Over time, this can lead to over-discharge damage to the battery. Utility Model Content

[0004] The technical problem to be solved by the present invention is to provide a main and backup power management circuit for preventing battery over-discharge in view of the above-mentioned defects in the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a main and backup power management circuit to prevent battery over-discharge, including a power supply protection circuit, a system control circuit, a first resistor and a current-type switch; the power supply protection circuit includes a voltage-type switch, one end of the voltage-type switch is electrically connected to the battery, and the other end of the voltage-type switch is electrically connected to the system control circuit; the system control circuit is also electrically connected to the current-type switch, and the current-type switch is also electrically connected to the voltage-type switch; one end of the first resistor is electrically connected between the battery and the voltage-type switch, and the other end of the first resistor is electrically connected between the current-type switch and the voltage-type switch; the system control circuit is used to control the current-type switch to be opened or closed, and when the current-type switch is opened or closed, the voltage-type switch is opened or closed accordingly.

[0006] In some embodiments, the current-mode switch is a first transistor; and the voltage-mode switch is a MOS transistor.

[0007] In some embodiments, the battery is connected through a battery interface; a first pin of the battery interface is electrically connected to a fuse, an end of the fuse away from the battery interface is electrically connected to the source of the MOS tube and the first resistor, respectively, and the drain of the MOS tube is electrically connected to the power supply input end of the system control circuit; an end of the first resistor away from the fuse is electrically connected to the gate of the MOS tube, and the gate of the MOS tube is also electrically connected to the first transistor; a second pin of the battery interface is grounded.

[0008] In some embodiments, the power supply protection circuit further includes a second resistor, a second triode, a third resistor, a first capacitor and an elastic switch; the gate of the MOS tube is also electrically connected to the second resistor, and the end of the second resistor away from the MOS tube is electrically connected to the first triode and the second triode respectively; the collector of the second triode is electrically connected to the second resistor, the emitter of the second triode is grounded, the base of the second triode is electrically connected to the third resistor, the end of the third resistor away from the second triode is electrically connected to the first capacitor, and the end of the first capacitor away from the third resistor is electrically connected to the elastic switch; the elastic switch is also electrically connected to the VBAT end of the system control circuit.

[0009] In some embodiments, the power supply protection circuit also includes a fourth resistor, a second capacitor, a fifth resistor, a sixth resistor and a third capacitor; the base of the second transistor is also electrically connected to the fourth resistor and the second capacitor, respectively, and the ends of the fourth resistor and the second capacitor away from the second transistor are both grounded; the end of the first capacitor away from the third resistor is also electrically connected to the fifth resistor, and the end of the fifth resistor away from the first capacitor is respectively electrically connected to the sixth resistor, the third capacitor and the VBAT_Test end of the system control circuit; the ends of the sixth resistor and the third capacitor away from the fifth resistor are both grounded.

[0010] In some embodiments, the collector of the first transistor is electrically connected to an end of the second resistor away from the MOS transistor and the collector of the second transistor, respectively; the base of the first transistor is electrically connected to a fourth capacitor and a seventh resistor, respectively, an end of the seventh resistor away from the first transistor is electrically connected to a control signal output end of the system control circuit, and an end of the fourth capacitor away from the first transistor and the emitter of the first transistor are both grounded.

[0011] In some embodiments, the MOS transistor is a P-channel MOS transistor.

[0012] In some embodiments, the first transistor and the second transistor are both NPN transistors.

[0013] The beneficial effects of the present invention are as follows: different from the prior art, the main and backup power management circuit for preventing battery over-discharge of the present invention includes a power supply protection circuit, a system control circuit, a first resistor and a current-type switch; the power supply protection circuit includes a voltage-type switch; the system control circuit is used to control the current-type switch to be opened or closed, and the voltage-type switch is opened or closed by controlling the current-type switch to be opened or closed; the power supply between the battery and the back-end system can be disconnected when the battery is undervoltage protected, the protection circuit does not consume current, and the battery no longer consumes power to the outside, effectively avoiding over-discharge damage of the battery due to not being charged for a long time after undervoltage protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a principle block diagram of the main and backup power management circuit for preventing battery over-discharge in an embodiment of the present utility model;

[0015] Figure 2 This is a circuit diagram of a main backup power management circuit for preventing battery over-discharge in an embodiment of the present utility model;

[0016] Names and numbers in the figure: power supply protection circuit-1; system control circuit-2; battery-3. DETAILED DESCRIPTION

[0017] The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of the present invention are used to distinguish between different items, not to describe a specific order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0018] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0019] "Multiple" refers to two or more. "And / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0020] Moreover, the terms "up, down, front, back, left, right, upper end, lower end" and the like indicating directions are all based on the posture and position of the device or apparatus described in this solution during normal use.

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The present utility model is implemented as follows Figure 1 and Figure 2 As shown in the figure, a main and backup power management circuit for preventing battery over-discharge includes a power supply protection circuit 1, a system control circuit 2, a first resistor R3 and a current-type switch S2; the power supply protection circuit 1 includes a voltage-type switch S1, one end of the voltage-type switch S1 is electrically connected to the battery 3, and the other end of the voltage-type switch S1 is electrically connected to the system control circuit 2; the system control circuit 2 is also electrically connected to the current-type switch S2, and the current-type switch S2 is also electrically connected to the voltage-type switch S1; one end of the first resistor R3 is electrically connected between the battery 3 and the voltage-type switch S1, and the other end of the first resistor R3 is electrically connected between the current-type switch S2 and the voltage-type switch S1; the system control circuit 2 is used to control the current-type switch S2 to be opened or closed, and when the current-type switch S2 is opened or closed, the voltage-type switch S1 is opened or closed accordingly.

[0023] In this embodiment, the system control circuit 2 includes a system control chip (not shown in the drawings), and the current-source switch S2 is controlled by the control signal output terminal of the system control chip (not shown in the drawings). The control logic of the current-source switch S2 and the voltage-source switch S1 is as follows: when the current-source switch S2 is closed, the voltage-source switch S1 is closed; when the current-source switch S2 is disconnected, the voltage-source switch S1 is disconnected. When it is detected that the voltage of the battery 3 is too low and needs to be disconnected, the current-source switch S2 is disconnected. Once the current-source switch S2 is disconnected, the battery 3 does not form a loop with the system ground. The voltage of the battery 3 continuously disconnects the voltage-source switch S1 through the first resistor R3, disconnecting the power supply between the battery 3 and the back-end system control circuit 2. The protection circuit does not consume current. After the battery 3 is undervoltage protected, it will no longer consume any external power, effectively preventing the battery 3 from being over-discharged and damaged due to not being charged for a long time after the undervoltage protection.

[0024] The current-mode switch S2 is a first transistor Q3, which is a current-mode switching device. The voltage-mode switch S1 is a MOS transistor Q1, which is a voltage-mode switching device. Specifically, the MOS transistor Q1 is a P-channel MOS transistor Q1. Both the first transistor Q3 and the second transistor Q2 are NPN transistors.

[0025] Specifically, the battery 3 is connected through the battery interface J1; the first pin of the battery interface J1 is electrically connected to the fuse FBI, and the end of the fuse FBI away from the battery interface J1 is electrically connected to the source of the MOS transistor Q1 and the first resistor R3, respectively, and the drain of the MOS transistor Q1 is electrically connected to the power supply input end of the system control circuit 2; the end of the first resistor R3 away from the fuse FBI is electrically connected to the gate of the MOS transistor Q1, and the gate of the MOS transistor Q1 is also electrically connected to the first transistor Q3; the second pin of the battery interface J1 is grounded.

[0026] Specifically, the power supply protection circuit 1 also includes a second resistor R1, a second transistor Q2, a third resistor R2, a first capacitor C1 and an elastic switch SW1; the gate of the MOS transistor Q1 is also electrically connected to the second resistor R1, and the end of the second resistor R1 away from the MOS transistor Q1 is electrically connected to the first transistor Q3 and the second transistor Q2 respectively; the collector of the second transistor Q2 is electrically connected to the second resistor R1, the emitter of the second transistor Q2 is grounded, the base of the second transistor Q2 is electrically connected to the third resistor R2, the end of the third resistor R2 away from the second transistor Q2 is electrically connected to the first capacitor C1, and the end of the first capacitor C1 away from the third resistor R2 is electrically connected to the elastic switch SW1; the elastic switch SW1 is also electrically connected to the VBAT terminal of the system control circuit 2.

[0027] Specifically, the power supply protection circuit 1 also includes a fourth resistor R5, a second capacitor C2, a fifth resistor R4, a sixth resistor R7 and C4; the base of the second transistor Q2 is also electrically connected to the fourth resistor R5 and the second capacitor C2, respectively, and the fourth resistor R5 and the second capacitor C2 are both grounded at one end away from the second transistor Q2; the first capacitor C1 is also electrically connected to the fifth resistor R4 at one end away from the third resistor R2, and the fifth resistor R4 is electrically connected to the sixth resistor R7, C4 and the VBAT_Test end of the system control circuit 2 at one end away from the first capacitor C1; the sixth resistor R7 and C4 are both grounded at one end away from the fifth resistor R4.

[0028] Specifically, the collector of the first transistor Q3 is electrically connected to an end of the second resistor R1 away from the MOS transistor Q1 and the collector of the second transistor Q2, respectively; the base of the first transistor Q3 is electrically connected to a fourth capacitor C3 and a seventh resistor R6, respectively; an end of the seventh resistor R6 away from the first transistor Q3 is electrically connected to the control signal output end of the system control circuit 2; an end of the fourth capacitor C3 away from the first transistor Q3 and the emitter of the first transistor Q3 are both grounded.

[0029] The working principle of the main backup power management circuit for preventing battery over-discharge in this embodiment is described below: Figure 2 In the circuit diagram shown, during normal power supply, the first transistor Q3 is kept closed by the back-end system control circuit, providing stable power to the back-end system control circuit. At this time, current flows through the power protection circuit. When the system control chip (not shown) in the back-end system control circuit detects that the voltage of battery 3 is low and reaches the protection point, it controls the first transistor Q3 to be disconnected, and the system control chip (not shown) in the back-end system control circuit automatically shuts off power. At this point, the first transistor Q3 loses its control signal and remains disconnected. In this state, because MOS transistor Q1 is a voltage-controlled device, its control pin is maintained disconnected by the voltage signal of battery 3 through first resistor R3. Because battery 3 has no current loop to ground, it no longer provides any power to the entire system.

[0030] MOS transistor Q1, first transistor Q3, and second transistor Q2 all function as electronic switches. Battery 3 is connected to battery connector J1. The positive terminal of battery 3 is connected to the back-end circuit via fuse FB1, which protects battery 3 in the event of a short circuit. Charging directly charges battery 3, and charging is possible when the 220V main power supply is active. When the 220V main power supply is powered down, pressing and closing flexible switch SW1 triggers a pulse through first capacitor C1, turning on second transistor Q2. The duration of the pulse can be controlled by adjusting the capacitance of first capacitor C1. After the pulse, second transistor Q2 automatically turns off. During the pulse, second transistor Q2 remains on. Once turned on, the gate of MOS transistor Q1 is connected to ground via second resistor R1, turning on MOS transistor Q1. Battery 3 then powers the back-end system control circuit.

[0031] After the entire system is powered by battery 3, it operates normally. The voltage of battery 3 is read through the VBAT_Test port. When there is voltage, the flexible switch SW1 is pressed. The BAT_PowerOff port is then controlled to output a high level to turn on the second transistor Q3. The gate of MOS transistor Q1 is connected to the first transistor Q3 through the second resistor R1 and then to ground. At this time, even if the second transistor Q2 automatically turns off after the pulse and the flexible switch SW1 is disconnected, the first transistor Q3 is controlled by the system control circuit to remain on, and battery 3 continues to power the entire system. After the entire system is operating, the voltage of battery 3 can be detected through the +12V_BATT port. When it is detected that the voltage of battery 3 reaches the preset protection point, the second transistor Q3 is turned off by outputting a low level through BAT_PowerOff, thereby turning off MOS transistor Q1 and disconnecting the entire system and battery 3.

[0032] After the entire system loses power, the flexible switch SW1 is disconnected, along with the second transistor Q2, the first transistor Q3, and the MOS transistor Q1. The entire system has no power-consuming circuits, and battery 3 no longer discharges. To manually shut down the system while battery 3 is powering it, long-press the flexible switch SW1. The VBAT_Test port detects that the switch has been pressed for a specified period of time and shuts down power via BAT_PowerOff.

[0033] The main and backup power management circuit for preventing battery over-discharge in the embodiment of the present invention is simpler in design, uses fewer components, is low in cost, is simple to implement, has better effects and is safer, and can better achieve power-off and protection in a physical sense.

[0034] It should be understood that ordinary technical workers in this field can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to this utility model.

Claims

1. A main and backup power management circuit for preventing battery over-discharge, characterized by: The device comprises a power supply protection circuit, a system control circuit, a first resistor, and a current-mode switch; the power supply protection circuit includes a voltage-mode switch, one end of which is electrically connected to a battery, and the other end of which is electrically connected to the system control circuit; the system control circuit is also electrically connected to the current-mode switch, and the current-mode switch is also electrically connected to the voltage-mode switch; one end of the first resistor is electrically connected between the battery and the voltage-mode switch, and the other end of the first resistor is electrically connected between the current-mode switch and the voltage-mode switch; The system control circuit is used to control the current-mode switch to be opened or closed. When the current-mode switch is opened or closed, the voltage-mode switch is opened or closed accordingly.

2. The main and backup power management circuit for preventing battery over-discharge according to claim 1, characterized in that: The current-mode switch is a first transistor; the voltage-mode switch is a MOS transistor.

3. The main and backup power management circuit for preventing battery over-discharge according to claim 2, characterized in that: The battery is connected through a battery interface; a first pin of the battery interface is electrically connected to a fuse, an end of the fuse away from the battery interface is electrically connected to the source of the MOS tube and the first resistor, respectively, and the drain of the MOS tube is electrically connected to the power supply input end of the system control circuit; an end of the first resistor away from the fuse is electrically connected to the gate of the MOS tube, and the gate of the MOS tube is also electrically connected to the first transistor; a second pin of the battery interface is grounded.

4. The main and backup power management circuit for preventing battery over-discharge according to claim 3, characterized in that: The power supply protection circuit also includes a second resistor, a second triode, a third resistor, a first capacitor and an elastic switch; the gate of the MOS tube is also electrically connected to the second resistor, and the end of the second resistor away from the MOS tube is electrically connected to the first triode and the second triode respectively; the collector of the second triode is electrically connected to the second resistor, the emitter of the second triode is grounded, the base of the second triode is electrically connected to the third resistor, the end of the third resistor away from the second triode is electrically connected to the first capacitor, and the end of the first capacitor away from the third resistor is electrically connected to the elastic switch; the elastic switch is also electrically connected to the VBAT terminal of the system control circuit.

5. The main and backup power management circuit for preventing battery over-discharge according to claim 4, characterized in that: The power supply protection circuit also includes a fourth resistor, a second capacitor, a fifth resistor, a sixth resistor and a third capacitor; the base of the second transistor is also electrically connected to the fourth resistor and the second capacitor, respectively, and the ends of the fourth resistor and the second capacitor away from the second transistor are both grounded; the end of the first capacitor away from the third resistor is also electrically connected to the fifth resistor, and the end of the fifth resistor away from the first capacitor is electrically connected to the sixth resistor, the third capacitor and the VBAT_Test end of the system control circuit, respectively; the ends of the sixth resistor and the third capacitor away from the fifth resistor are both grounded.

6. The main and backup power management circuit for preventing battery over-discharge according to any one of claims 2 to 5, characterized in that: The collector of the first transistor is electrically connected to an end of the second resistor away from the MOS transistor and the collector of the second transistor respectively; the base of the first transistor is electrically connected to a fourth capacitor and a seventh resistor respectively, an end of the seventh resistor away from the first transistor is electrically connected to a control signal output end of the system control circuit, and an end of the fourth capacitor away from the first transistor and the emitter of the first transistor are both grounded.

7. The main and backup power management circuit for preventing battery over-discharge according to any one of claims 2 to 5, characterized in that: The MOS transistor is a P-channel MOS transistor.

8. The main and backup power management circuit for preventing battery over-discharge according to claim 4 or 5, characterized in that: The first transistor and the second transistor are both NPN transistors.

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