Lithium battery charging circuit with electric spark prevention and power supply switching functions

Abstract

The utility model relates to the technical field of power management, and provides a lithium battery charging circuit with electric spark prevention and power supply switching functions, which comprises an electric spark generation prevention circuit connected with a power adapter, and the electric spark generation prevention circuit is connected with a lithium battery through a charging module. The electric spark generation prevention circuit and the battery are connected with the dual-power-supply switching circuit, the dual-power-supply switching circuit is connected with the DC voltage stabilization module, and the DC voltage stabilization module is connected with the load. According to the utility model, the electric spark generation prevention circuit is arranged between the power adapter and the charging module, so that electric sparks generated when the power adapter is inserted into a DC socket are avoided, potential safety hazards are eliminated, and the dual-power switching circuit connected with the electric spark generation circuit and the battery is arranged, so that the battery stops supplying power when the power adapter supplies power; the stability of the power supply voltage is ensured, the charging and discharging times of the battery are reduced, and the service life of the battery is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of power management, in particular to a lithium battery charging circuit with spark protection and power supply switching functions. Background Art

[0002] In the process of electronic product project development, especially when encountering battery-powered projects, you need to deal with lithium batteries. When developing projects powered by lithium batteries, you will face the problem of lithium battery charging circuits.

[0003] The rear visual device of existing visual dual-chamber products is usually a dual power supply mode, with a built-in rechargeable lithium battery and an external charging socket, which is convenient for charging the lithium battery and powering the entire device. The visual device has two power supply modes, one is powered by the internal lithium battery, and the other is powered by the power adapter. When the power adapter is inserted into the charging socket, the power adapter charges the battery through the charging module. At this time, the battery still supplies power to the load through the DC module, which will cause the overall power supply voltage to be unstable and affect the charging efficiency. The battery is discharged while charging, which will cause the battery life to decrease rapidly and the capacity to decay. In addition, when the power adapter is inserted into the charging socket, a large current will be generated at the moment when the two plug contacts come into contact with the socket. The large current will break through the air and produce electric sparks, which will not only affect the life of the charging socket, but also may cause certain harm to the operator, posing a safety hazard. Utility Model Content

[0004] Based on this, the purpose of the utility model is to provide a lithium battery charging circuit with spark protection and power supply switching functions in view of the deficiencies in the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A lithium battery charging circuit with spark protection and power supply switching functions, characterized in that it includes an spark protection circuit connected to a power adapter, the spark protection circuit is connected to a lithium battery through a charging module, the spark protection circuit and the battery are connected to a dual power supply switching circuit, the dual power supply switching circuit is connected to a DC voltage stabilizing module, and the DC voltage stabilizing module is connected to a load.

[0007] As a further improvement of the utility model, the circuit for preventing electric spark generation includes a P-channel MOS tube Q1, the P-channel MOS tube Q1 includes a G pole, an S pole and a D pole, the G pole is connected to ground in series through a voltage-dividing resistor R2, and a voltage-dividing resistor R1 and a capacitor C1 are connected in parallel between the G pole and the S pole.

[0008] As a further improvement of the present invention, the capacitor C1 can be replaced according to the voltage of the power adapter, and the delayed power-on time can be adjusted by adjusting the capacitance value of the capacitor C1.

[0009] As a further improvement of the utility model, the circuit for preventing electric sparks from being generated includes a P-channel MOS tube Q2, the P-channel MOS tube Q2 includes a G pole, an S pole and a D pole, the G pole is connected to ground in series through a resistor R3, the G pole is connected to the power adapter voltage, the D pole is connected to the lithium battery voltage VBAT, a diode D2 is connected in parallel between the G pole and the S pole, and the S pole and the cathode of the diode D2 are both connected to the power supply voltage VCC.

[0010] As a further improvement of the present invention, when the power adapter is connected, the power supply voltage VCC of the power adapter is output through the cathode of the diode D2, and when the power adapter is not connected, the power supply voltage VCC of the lithium battery is output through the S pole of the P-channel MOS tube Q2.

[0011] As a further improvement of the utility model, the power adapter is connected to the spark prevention circuit via a DC socket.

[0012] As a further improvement of the present invention, a filtering structure is provided between each module of the lithium battery charging circuit with spark protection and power supply switching functions.

[0013] As a further improvement of the present invention, a filter inductor L1 is connected in series between the power adapter and the spark prevention circuit, and filter capacitors C2 and C3 are connected in parallel between the spark prevention circuit and the dual power switching circuit.

[0014] As a further improvement of the present invention, the lithium battery can be selected from 1 to 4 lithium batteries in series.

[0015] As a further improvement of the present invention, the voltage of the DC voltage stabilizing module can be selected from 12V, 5V, and 3.3V.

[0016] The beneficial effects of the utility model are:

[0017] 1. The utility model provides a lithium battery charging circuit with spark protection and power supply switching functions. By providing a spark protection circuit between a power adapter and a charging module, sparks generated when the power adapter is plugged into a DC socket are avoided, thereby eliminating potential safety hazards. By providing a dual power supply switching circuit connected to the spark generation circuit and the battery, the battery stops supplying power when the power adapter is supplying power, thereby ensuring the stability of the power supply voltage, reducing the number of battery charge and discharge times, and saving the battery life.

[0018] 2. The utility model is provided with an anti-spark circuit in the charging circuit, which delays power-on through the P-channel MOS tube Q1, resistors R1, R2 and capacitor C1. When the power adapter is inserted into the DC socket, the P-channel MOS tube Q1 is not turned on, thereby avoiding the spark generated by the large current breaking through the air at the moment of power-on, avoiding the risk of injury to the operator caused by the spark, and ensuring the safety of the charging circuit.

[0019] 3. The utility model is designed with a dual power switching circuit in the charging circuit. When the power adapter is inserted, the power adapter voltage enters the charging module after passing through the spark protection circuit to charge the lithium battery. Since the power adapter voltage is greater than the lithium battery voltage, the P-channel MOS tube Q2 is not turned on at this time, and the lithium battery does not supply power. The power adapter voltage enters the DC voltage regulator module through the diode D2 while charging the lithium battery to supply power to the load, thereby ensuring the stability of the power supply voltage during the lithium battery charging process, reducing the number of times the lithium battery is used, and extending the life of the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Attached Figure 1 It is a schematic diagram of the overall circuit structure of the utility model.

[0022] Attached Figure 2 It is a schematic diagram of the structure of the spark prevention circuit module and the dual power supply switching circuit module of the utility model.

[0023] Attached Figure 3 This is a schematic diagram of the structure of the DC voltage stabilizing module of the utility model.

[0024] Attached Figure 4 This is a schematic diagram of the structure of the charging module of the utility model. Implementation

[0025] The technical solutions in the embodiments of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] like Figure 1As shown, a lithium battery charging circuit with anti-spark and power supply switching functions is characterized in that it includes an anti-spark generating circuit connected to a power adapter, the anti-spark generating circuit is connected to a lithium battery through a charging module, the anti-spark generating circuit and the battery are connected to a dual power supply switching circuit, the dual power supply switching circuit is connected to a DC voltage stabilizing module, and the DC voltage stabilizing module is connected to a load.

[0027] In a specific embodiment, further, the circuit for preventing electric spark generation includes a P-channel MOS tube Q1, the P-channel MOS tube Q1 includes a G pole, an S pole and a D pole, the G pole is connected to ground in series through a voltage-dividing resistor R2, and a voltage-dividing resistor R1 and a capacitor C1 are connected in parallel between the G pole and the S pole.

[0028] In a specific embodiment, further, the C1 capacitor has a delay effect. The larger the capacitance of the C1 capacitor, the longer the charging time required, and the longer the time required for the P-channel MOS tube Q1 to be turned on. The capacitor C1 can be replaced according to the voltage of the power adapter, and the delay power-on time can be adjusted by adjusting the capacitance value of the capacitor C1.

[0029] In a specific embodiment, further, the circuit for preventing electric sparks from being generated includes a P-channel MOS tube Q2, the P-channel MOS tube Q2 includes a G pole, an S pole and a D pole, the G pole is connected to the ground in series through a resistor R3, the G pole is connected to the power adapter voltage, the D pole is connected to the lithium battery voltage VBAT, a diode D2 is connected in parallel between the G pole and the S pole, and the S pole and the cathode of the diode D2 are both connected to the power supply voltage VCC.

[0030] In a specific embodiment, further, when the power adapter is connected, the power supply voltage VCC of the power adapter is output through the cathode of the diode D2, and when the power adapter is not connected, the power supply voltage VCC of the lithium battery is output through the S pole of the P-channel MOS tube Q2.

[0031] In a specific embodiment, further, the power adapter is connected to the spark protection circuit via a DC socket.

[0032] In a specific embodiment, further, a filtering structure is provided between each module of the lithium battery charging circuit with spark protection and power supply switching functions.

[0033] In a specific embodiment, further, a filter inductor L1 is connected in series between the power adapter and the spark prevention circuit, and filter capacitors C2 and C3 are connected in parallel between the spark prevention circuit and the dual power switching circuit.

[0034] In a specific embodiment, further, the lithium battery can be selected to be 1-4 lithium batteries in series.

[0035] In a specific embodiment, further, the voltage of the DC voltage stabilizing module can be selected from 12V, 5V, and 3.3V.

[0036] The specific workflow is:

[0037] When the power adapter is not connected, in the dual power switching circuit, the lithium battery voltage VBAT reaches the S pole of the P-channel MOS tube Q2 through the body diode of the P-channel MOS tube Q2. At this time, the S pole voltage is greater than the G pole voltage, so that Vgs<0, the P-channel MOS tube Q2 is turned on, the battery voltage VBAT reaches the VCC point, and the load is powered by the DC voltage regulator module.

[0038] When the power adapter is connected, in the anti-spark circuit, since the voltage across the capacitor C1 will not change suddenly, at this time, the G pole voltage of the P-channel MOS tube Q1 is equal to the S pole voltage, so the P-channel MOS tube Q1 is not turned on. As time goes by, the G pole voltage of the P-channel MOS tube Q1 continuously charges the capacitor C1 through the resistor R2, and the G pole voltage of the P-channel MOS tube Q1 gradually decreases. When the G pole voltage of the P-channel MOS tube Q1 decreases to the lowest threshold, the S level voltage is greater than the G level voltage, Vgs<0, and the P-channel MOS tube Q1 is turned on at this time. The power adapter voltage passes through the P-channel MOS tube Q1 to supply power to the charging module and the dual power switching circuit respectively. At this time, the power adapter has been installed and no sparks will be generated at the joint.

[0039] When the power adapter voltage reaches the dual power switching circuit, the G pole voltage of the P-channel MOS tube Q2 is the power adapter voltage, and the S pole voltage is the lithium battery voltage VBAT. Since the power adapter voltage is greater than the lithium battery voltage VBAT, Vgs>0, the P-channel MOS tube Q2 is not turned on, and the lithium battery voltage VBAT no longer supplies power to the dual power switching circuit. The power adapter voltage reaches the VCC point through the diode D2, and the load is powered by the DC voltage regulator module.

[0040] It can be understood that the above specific description of the utility model is only used to illustrate the utility model and is not limited to the technical solution described in the embodiments of the utility model. Ordinary technicians in the field should understand that the utility model can still be modified or replaced by equivalents to achieve the same technical effect; as long as the use requirements are met, they are within the protection scope of the utility model.

[0041] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

Claims

1. A lithium battery charging circuit with spark protection and power supply switching function, characterized in that: It includes an anti-spark generation circuit connected to a power adapter, the anti-spark generation circuit is connected to a lithium battery through a charging module, the anti-spark generation circuit and the battery are connected to a dual power supply switching circuit, the dual power supply switching circuit is connected to a DC voltage stabilizing module, and the DC voltage stabilizing module is connected to a load.

2. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: The spark prevention circuit includes a P-channel MOS transistor Q1, which includes a G pole, an S pole and a D pole. The G pole is connected to the ground in series through a voltage-dividing resistor R2, and a voltage-dividing resistor R1 and a capacitor C1 are connected in parallel between the G pole and the S pole.

3. The lithium battery charging circuit with spark protection and power supply switching function according to claim 2, characterized in that: The capacitor C1 can be replaced according to the voltage of the power adapter, and the delayed power-on time can be adjusted by adjusting the capacitance value of the capacitor C1.

4. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: The circuit for preventing electric spark generation includes a P-channel MOS tube Q2, and the P-channel MOS tube Q2 includes a G pole, an S pole and a D pole. The G pole is connected to the ground in series through a resistor R3, the G pole is connected to the power adapter voltage, the D pole is connected to the lithium battery voltage VBAT, a diode D2 is connected in parallel between the G pole and the S pole, and the S pole and the cathode of the diode D2 are both connected to the power supply voltage VCC.

5. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: When the power adapter is connected, the power supply voltage VCC of the power adapter is output through the cathode of the diode D2. When the power adapter is not connected, the power supply voltage VCC of the lithium battery is output through the S pole of the P-channel MOS tube Q2.

6. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: The power adapter is connected to the spark prevention circuit via a DC socket.

7. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: A filtering structure is provided between each module of the lithium battery charging circuit with spark protection and power supply switching functions.

8. The lithium battery charging circuit with spark protection and power supply switching function according to claim 7, characterized in that: A filter inductor L1 is connected in series between the power adapter and the spark prevention circuit, and filter capacitors C2 and C3 are connected in parallel between the spark prevention circuit and the dual power switching circuit.

9. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: The lithium battery can be selected from 1 to 4 lithium batteries in series.

10. The lithium battery charging circuit with spark protection and power supply switching function according to claim 1, characterized in that: The voltage of the DC voltage stabilizing module can be selected from 12V, 5V, and 3.3V.

Images