A battery charging anti-backflow circuit

Abstract

The utility model discloses a battery charging backflow prevention circuit, including an input end connected to an external charging circuit, a P-MOS circuit connected to the input end, an output end of the P-MOS circuit connected to a battery to be charged, two ends of the P-MOS circuit respectively connected to a control circuit, and also including a current and voltage detection circuit arranged on the output end of the P-MOS circuit and the battery path. In the utility model, by adding a current and voltage detection circuit in the circuit, it can monitor the current and voltage changes during the battery charging process, and the current and voltage detection circuit will quickly transmit the relevant information to the control circuit, and the control circuit controls the P-MOS circuit to be turned on or off, thereby preventing the current backflow from damaging the battery and the charging circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and more specifically, to a battery charging backflow prevention circuit. Background Art

[0002] Nowadays, people have more and more demands for battery charging circuits. Various new circuits are constantly being designed and applied to various battery chargers, which provide great convenience for people's lives. However, after the battery is fully charged, when the battery and the charger are not separated, a small part of the battery energy will be discharged through the charger, causing energy waste. If a diode is added to the output end of the charger to prevent the battery energy from flowing back, the diode PN junction will suffer large losses when overcurrent occurs, and the purpose of energy saving cannot be achieved.

[0003] For example, patent number CN201922103559.8 discloses a battery charging backflow prevention circuit. In this circuit, there is no current detection circuit, and the voltage and current changes at the charger output end and the battery end cannot be monitored at any time. The on or off of the P-MOS circuit cannot be controlled in time, resulting in excessive voltage drop and severe heat generation of the transistors in the P-MOS circuit. After long-term use, the transistors in the P-MOS circuit are prone to failure. Utility Model Content

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages to be described below.

[0005] In order to achieve these purposes and other advantages according to the utility model, a battery charging backflow prevention circuit is provided, including an input end connected to an external charging circuit, a P-MOS circuit connected to the input end, an output end of the P-MOS circuit connected to a battery to be charged, two ends of the P-MOS circuit respectively connected to a control circuit, and also including a current and voltage detection circuit arranged on a path between the output end of the P-MOS circuit and the battery.

[0006] Preferably, the control circuit includes: a single-chip microcomputer, a P14 pin of the single-chip microcomputer is connected to one end of a transistor, a PA5 pin of the single-chip microcomputer is communicatively connected to a current and voltage detection circuit, one end of the transistor is connected to a P-MOS circuit, the other end of the transistor is grounded, and the other end is connected to the output end of the P-MOS circuit.

[0007] Preferably, the current and voltage detection circuit includes: a current sensing resistor arranged on the battery and P-MOS path, the two ends of the current sensing resistor are respectively connected to the two positive and negative input pins of the current detection chip, and the output pin of the current detection chip is connected to the PA5 pin of the microcontroller.

[0008] The utility model includes at least the following beneficial effects: in the utility model, by adding a current and voltage detection circuit in the circuit, it can monitor the current and voltage changes during the battery charging process, and the current and voltage detection circuit will quickly transmit the relevant information to the control circuit, and the control circuit controls the P-MOS circuit to be turned on or off, thereby preventing current backflow from damaging the battery and the charging circuit.

[0009] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the utility model.

[0011] Figure 2 It is a circuit diagram of the utility model.

[0012] Markings in the figure: 1. External charging circuit, 2. P-MOS circuit, 3. Battery to be charged, 4. Microcontroller, 5. Transistor, 6. Current sensing resistor, 7. Current detection chip. DETAILED DESCRIPTION

[0013] The present invention will be further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0014] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0015] It should be noted that in the description of the present invention, the orientation or position relationship indicated by the term is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0016] In the description of the present utility model, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "sleeved / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to specific circumstances.

[0017] In addition, in the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0018] Figure 1 A battery charging backflow prevention circuit of the present invention is shown, including an input end connected to an external charging circuit 1, a P-MOS circuit connected to the input end, an output end of the P-MOS circuit connected to a battery 3 to be charged, two ends of the P-MOS circuit respectively connected to a control circuit, and also including a current and voltage detection circuit arranged on the output end of the P-MOS circuit and the battery path.

[0019] Working principle:

[0020] When the voltage at the input end connected to the external charging circuit 1 is higher than the voltage at the end of the battery 3 to be charged during the battery charging stage, the gate voltage of the P-MOS tube, as the core component of the circuit, is precisely controlled by the control circuit. When the external charging circuit 1 is connected to the input end and starts to charge the battery 2 to be charged, the internal circuit is detected according to the current and voltage detection circuit, and the control circuit adjusts the gate voltage of the P-MOS tube according to real-time requirements and system status. In the charging working state, the P-MOS tube is turned on at an appropriate gate voltage, allowing the charging current to flow from the input end through the P-MOS tube and finally reach the battery for charging.

[0021] When the battery is fully charged, the current and voltage detection circuit detects the internal circuit. If the voltage at the input end connected to the external charging circuit 1 is lower than the voltage at the battery end, the control circuit adjusts the gate voltage of the P-MOS tube, causing it to change from the on state to the off state, thereby cutting off the charging current and preventing the current from flowing back into the charging circuit or damaging other circuit components.

[0022] In the above scheme, the control circuit includes: a single-chip microcomputer 4, a P14 pin of the single-chip microcomputer 4 is connected to one end of a transistor 5, a PA5 pin of the single-chip microcomputer 4 is connected to a current and voltage detection circuit, one end of the transistor 5 is connected to a P-MOS circuit, the other end of the transistor 5 is grounded, and the other end is connected to the output end of the P-MOS circuit. With this technical method, the single-chip microcomputer 4 is responsible for receiving and processing information from the current and voltage detection circuit, and controls the switch state of the transistor 5 according to this information, thereby controlling the on and off of the P-MOS circuit 2. The PA5 pin of the single-chip microcomputer 4 is connected to the current and voltage detection circuit. The current and voltage detection circuit monitors the current and voltage on the output end of the P-MOS circuit 2 and the battery path in real time, and sends the relevant information to the single-chip microcomputer 4 through the PA5 pin. After receiving this information, the single-chip microcomputer 4 will quickly process and analyze it.

[0023] When the voltage at the input end connected to the external charging circuit 1 is higher than the voltage at the battery end, the single chip computer 4 outputs the signal to the transistor 5 through the P14 pin, the transistor 5 is turned on, and the collector and emitter of the transistor 5 are respectively connected to the gate and source of the P-MOS circuit 2. The conduction of the P-MOS circuit 2 ensures the normal progress of the charging process.

[0024] However, if the single-chip computer 4 finds through the current and voltage detection circuit that the voltage at the input end connected to the external charging circuit 1 is lower than the voltage at the battery end, it will immediately adjust the output state of the P14 pin. By changing the level signal of the P14 pin, the single-chip computer 4 can control the cutoff of the transistor 5. Thus, the path between the output end of the P-MOS circuit 2 and the battery is cut off, realizing the function of preventing backflow.

[0025] In the above scheme, the current and voltage detection circuit includes: a current detection resistor 6 arranged on the battery and P-MOS path, the two ends of the current detection resistor 6 are respectively connected to the two positive and negative input pins of the current detection chip 7, and the output pin of the current detection chip 7 is connected to the PA5 pin of the single-chip computer 4. Using this technical method, the two ends of the current detection resistor 6 are respectively connected to the two positive and negative input pins of the current detection chip 7. When the current flows through the current detection resistor 6, according to Ohm's law, a voltage drop proportional to the current magnitude will be generated on the current detection resistor 6. This voltage drop is captured by the two input pins of the current detection chip 7, and is converted into a measurable voltage signal after being processed by the internal circuit. The output pin of the current detection chip 7 is connected to the PA5 pin of the single-chip computer 4. In this way, the voltage signal output by the current detection chip 7 can be read by the single-chip computer 4. The single-chip computer 4 receives the voltage signal through the PA5 pin, and according to the series voltage division principle, can obtain the voltage of the input end connected to the external charging circuit 1 and the voltage of the battery end. According to the values ​​of the two voltages, the single-chip computer 4 controls the transistor 5 to realize the conduction or cutoff of the P-MOS circuit 2.

[0026] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation modes. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A battery charging backflow prevention circuit, comprising an input end connected to an external charging circuit, a P-MOS circuit connected to the input end, an output end of the P-MOS circuit connected to a battery to be charged, and two ends of the P-MOS circuit respectively connected to a control circuit, characterized in that: It also includes a current and voltage detection circuit arranged on the output end of the P-MOS circuit and the battery path.

2. The battery charging backflow prevention circuit according to claim 1, characterized in that: The control circuit includes: a single-chip microcomputer, a P14 pin of the single-chip microcomputer is connected to one end of a transistor, a PA5 pin of the single-chip microcomputer is communicatively connected to a current and voltage detection circuit, one end of the transistor is connected to a P-MOS circuit, the other end of the transistor is grounded, and the other end is connected to the output end of the P-MOS circuit.

3. The battery charging backflow prevention circuit according to claim 1, characterized in that: The current and voltage detection circuit includes: a current detection resistor arranged on the battery and P-MOS path, the two ends of the current detection resistor are respectively connected to the two positive and negative input pins of the current detection chip, and the output pin of the current detection chip is connected to the PA5 pin of the microcontroller.

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