Dual-power-supply, low-dropout and anti-reverse-charging circuit

Abstract

The utility model discloses a dual power supply, low dropout and anti-reverse charging circuit, comprising a disposable battery power supply module used for providing power output; the direct-current power supply input module is used for providing a standby direct-current power supply; the MOS switch control circuit comprises a Q2 / Q4 providing a battery power supply access and a Q5 providing a direct-current power supply access; and the reverse charging prevention circuit cuts off a reverse charging access of the Q2 / Q4 to the disposable battery through the Q1 / Q3 when the direct-current power supply is input. According to the utility model, low-dropout power supply can be realized in a dual-power supply mode, reverse charging can be prevented, and a novel circuit which supports delayed power supply reset in a switching process can be realized, so that the residual electric quantity of a disposable battery can be better utilized, the safety of standby power supply and the stability of a system can be improved, and the requirements of users in various use scenes can be met.

Description

Technical Field

[0001] This utility model relates to an anti-reverse charging circuit, specifically an anti-reverse charging circuit with dual power supply, low voltage difference. Background Technology

[0002] Many electronic devices on the market today use disposable, non-rechargeable batteries (such as lithium-ion batteries) as their primary power source. These batteries offer advantages such as high energy density and long storage life, but their low voltage characteristics and non-rechargeability mean that the device cannot be used when the battery is depleted, impacting the user experience. Therefore, it is typically necessary to design a backup power interface (such as a DC power interface) in the device to provide temporary power support when the disposable battery is depleted.

[0003] However, existing technologies have the following problems in dual power supply and switching processes:

[0004] If an effective reverse charging protection circuit is not designed after connecting a backup DC power supply, the DC power supply may charge the disposable non-rechargeable battery through the circuit, which may not only damage the battery but also pose a safety hazard.

[0005] The voltage drop of the power switching circuit in the prior art is relatively high, which makes it difficult to effectively utilize the disposable battery when it is low in power, thus shortening the service life of the equipment.

[0006] After disconnecting the backup DC power supply, the system may switch directly to a disposable battery power supply, which may cause a momentary power outage and prevent the equipment from resetting properly, thus affecting the stable operation of the system. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a dual-power supply, low-dropout, reverse-charging-protected circuit. This circuit enables low-dropout power supply and prevents reverse charging in dual-power supply mode, while also supporting delayed power supply reset during switching. It can better utilize the remaining power of the disposable battery, improve the safety of backup power supply and system stability, and meet the needs of users in various usage scenarios.

[0008] This utility model is achieved through the following technical solution: a dual-power supply, low-dropout, reverse-charging protection circuit, comprising:

[0009] A disposable battery-powered module is used to provide power output;

[0010] DC power input module, used to provide backup DC power;

[0011] The MOS switch control circuit includes MOS transistors Q2 and Q4 for providing a battery power supply path, and MOS transistor Q5 for providing a DC power supply path.

[0012] The reverse charging protection circuit cuts off the reverse charging path to the primary battery when DC power is input through the MOSFETs Q1 and Q3.

[0013] The delayed power supply control circuit, including capacitors, voltage divider resistors and transistors, is used to delay the opening of the power supply path of a disposable battery after the DC power supply is disconnected.

[0014] As a preferred technical solution, the on-resistance of the MOS switch control circuit is less than 120mΩ to achieve a low voltage drop during power supply.

[0015] As a preferred technical solution, the anti-reverse charging circuit uses MOSFETs Q1 and Q3 to close the connection path with the disposable battery when a DC power input is detected, so as to prevent the DC power supply from reversing the charging of the disposable battery.

[0016] As a preferred technical solution, the delayed power supply control circuit includes:

[0017] At least one capacitor is used to store energy to generate a delay time;

[0018] At least one voltage divider resistor is used to adjust the delay time;

[0019] At least one transistor is used to control the conduction state of the MOSFETs Q2 and Q4, thereby achieving delayed power supply after the DC power supply is disconnected.

[0020] As a preferred technical solution, when a disposable battery and a DC power supply are connected at the same time, only the DC power supply is used for power supply, and the power supply path of the disposable battery is shut off through the MOS switch control circuit.

[0021] As a preferred technical solution, the on-resistance of the MOS switch control circuit is used to control the voltage difference of the primary battery to be less than 0.012V, so as to maximize the power utilization rate of the primary battery.

[0022] As a preferred technical solution, the DC power input module supports DC 5V power supply and is connected to the output terminal through the MOS switch control circuit.

[0023] As a preferred technical solution, the disposable battery is a lithium-ion battery, and the circuit supports the low-voltage operating state of the lithium-ion battery through the low on-resistance characteristics of the MOS.

[0024] The beneficial effects of this utility model are: by using a MOSFET as a power supply switching switch, this utility model realizes low voltage drop switching in dual power supply mode. The on-resistance of the MOSFET is as low as 120mΩ, ensuring that the voltage drop under normal operating current is extremely low, thereby making full use of the power of the disposable battery and enabling it to supply power efficiently in low voltage conditions.

[0025] By setting up an anti-reverse charging circuit, when a DC power source is connected, the charging path between the DC power source and the primary battery can be effectively cut off, preventing the DC power source from reversing the charging of the primary non-rechargeable battery, thus avoiding battery damage and potential safety hazards.

[0026] In addition, a delayed power supply control module is designed in the circuit. By using a combination of capacitors, voltage divider resistors and transistors, the disposable battery power supply path is opened after the DC power supply is disconnected, which ensures a smooth transition during the switching process and realizes system reset, thereby improving the stability and reliability of the equipment.

[0027] When a disposable battery and a DC power supply are connected at the same time, the circuit prioritizes the use of the DC power supply and shuts off the power supply path of the disposable battery, effectively reducing the consumption of the disposable battery.

[0028] Meanwhile, through optimized design, the entire circuit achieves an organic combination of functions such as low power supply dropout, reverse charging protection, and delayed reset. It is widely applicable to electronic devices that use disposable batteries, especially in scenarios where high power supply switching accuracy is required and space is limited, demonstrating significant technical advantages and practical application value. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0031] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0032] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0033] like Figure 1As shown, this utility model provides a dual-power supply, low-dropout, reverse-charging protection circuit. This circuit combines a disposable battery power supply module and a DC power input module, and achieves efficient switching between the two power supplies through a MOS switch control circuit. It also has reverse-charging protection and delayed power supply control functions, which can ensure stable operation of the device and extend the service life of the disposable battery under different power supply modes.

[0034] Specifically, the disposable battery power supply module in this invention provides power output to the device. This module supports lithium-ion batteries as disposable batteries, which are characterized by low voltage but high energy density, enabling them to provide stable power to the device for a relatively long period. Simultaneously, to address the situation where the disposable battery runs out of power, a DC power input module is included in the circuit design, supporting DC 5V power supply. This DC power input module provides backup power; when a DC power source is plugged in, it prioritizes switching to DC power supply, while simultaneously providing effective protection for the disposable battery.

[0035] To achieve efficient switching between the two power sources, a MOS switch control circuit is employed. This circuit includes MOSFETs Q1 and Q3, which control the power supply path for the primary battery, and MOSFET Q6, which controls the DC power supply path. The low on-resistance of the MOSFETs allows the circuit to maintain an extremely low voltage drop during power supply; specifically, its on-resistance is below 120mΩ, and the voltage drop under normal operating current conditions is as low as 0.012V. This low voltage drop design minimizes energy loss during primary battery power supply, ensuring a stable power output even at low voltage levels, thus improving battery utilization efficiency.

[0036] A key feature of this circuit is its reverse charging protection. By incorporating reverse charging protection, the circuit uses MOSFETs Q1 and Q3 to disconnect the DC power supply from the primary battery when a DC power source is input, preventing reverse charging of the primary battery. Since primary batteries (such as lithium-ion batteries) are non-rechargeable, reverse charging can not only damage the battery but also pose safety hazards. This reverse charging protection design safeguards the primary battery from reverse charging even when a DC power source is connected, ensuring the safety of the circuit operation.

[0037] Furthermore, to address the issue of potential momentary power loss when the DC power supply is disconnected, a delayed power supply control module was added to the circuit design. This module includes components such as capacitors, voltage divider resistors, and transistors. It stores energy in the capacitors and adjusts the voltage change time using the voltage divider resistors to control the switching action of the transistors. When the DC power supply is disconnected, the delayed power supply control module can delay the activation of MOSFETs Q2 and Q4, ensuring that the power supply path of the disposable battery is turned on at the appropriate time. This achieves a smooth power switching and avoids equipment malfunctions or data loss due to momentary power loss. In addition, this delayed switching also enables the automatic reset function of the equipment, further improving the reliability and stability of equipment operation.

[0038] In practical use, when both a disposable battery and a DC power supply are connected, the circuit design prioritizes DC power supply and uses a MOS switch to control the circuit to shut off the power supply to the disposable battery. This design effectively reduces the energy consumption of the disposable battery and extends its lifespan. Furthermore, after the DC power supply is disconnected, the circuit can smoothly switch back to disposable battery power, ensuring continuous operation of the device.

[0039] like Figure 1 As shown, this utility model uses MOS as a power supply switching switch to realize low differential voltage power input plus dual MOS control, so that when DC5V power is plugged in, the 5V to the disposable battery path is shut off to prevent reverse charging. RCQ is added to the control terminal to realize that when DC5V is disconnected and switched back to the disposable battery, the battery power supply is turned on after a delay to realize system power failure reset.

[0040] When powered by a normal disposable battery, Q2 and Q4 are on, and Q5 is off. The conducting MOSFET has a Ron of approximately 60mΩ. Assuming a current of 0.1A flows through, Vdrop = 0.1A * 120mΩ = 0.012V, which is an extremely low voltage drop, ensuring that the battery can be used until it is depleted.

[0041] When the disposable battery is depleted, a DC 5V circuit is plugged in. Q5 turns on, while Q2 and Q4 turn off. This ensures normal 5V power supply while preventing the 5V from charging the disposable battery through Q2 and Q4, thus preventing reverse charging. After the backup power supply operation is completed, the 5V power supply is disconnected. R1, C1, and Q1 will delay the turn-on of Q2, achieving delayed power supply during switching and resetting the backend equipment.

[0042] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope defined in the claims.

Claims

1. A dual power supply, low dropout, reverse charge prevention circuit, characterized by, include: A disposable battery-powered module is used to provide power output; DC power input module, used to provide backup DC power; The MOS switch control circuit includes MOS transistors Q2 and Q4 for providing a battery power supply path, and MOS transistor Q5 for providing a DC power supply path. The reverse charging protection circuit cuts off the reverse charging path to the primary battery when DC power is input through the MOSFETs Q1 and Q3. The delayed power supply control circuit, including capacitors, voltage divider resistors and transistors, is used to delay the opening of the power supply path of a disposable battery after the DC power supply is disconnected.

2. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The on-resistance of the MOS switch control circuit is less than 120mΩ to achieve a low voltage drop during power supply.

3. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The anti-reverse charging circuit uses MOSFETs Q1 and Q3 to close the connection path with the disposable battery when a DC power input is detected, so as to prevent the DC power supply from reversing the charging of the disposable battery.

4. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The delayed power supply control circuit includes: At least one capacitor is used to store energy to generate a delay time; At least one voltage divider resistor is used to adjust the delay time; At least one transistor is used to control the conduction state of the MOSFETs Q2 and Q4, thereby achieving delayed power supply after the DC power supply is disconnected.

5. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: When a disposable battery and a DC power supply are connected at the same time, only the DC power supply is used for power supply, and the power supply path of the disposable battery is shut off through the MOS switch control circuit.

6. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The on-resistance of the MOS switch control circuit is used to control the voltage difference of the primary battery to be less than 0.012V, so as to maximize the power utilization rate of the primary battery.

7. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The DC power input module supports DC 5V power supply and is connected to the output terminal through the MOS switch control circuit.

8. The dual supply, low dropout, reverse charge protection circuit of claim 1, wherein: The disposable battery is a lithium-ion battery, and the circuit supports the low-voltage operation of the lithium-ion battery through the low on-resistance characteristics of the MOS.

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