A simple 5V and 3V lithium battery charging system

Abstract

The utility model discloses a simple 5V and 3V lithium battery charging system, including a 5V lithium battery charging circuit and a 3V lithium battery charging circuit. The 5V lithium battery charging circuit includes an input side connector CN1, a protection diode D1, an energy storage capacitor EC1, a current limiting resistor R1, a voltage stabilizing chip U1, a diode D3, a transformer T1, a rectifier circuit, an input side connector CN2 and an output side connector CN2, and can output a 5V DC voltage; the 3V lithium battery charging circuit includes a capacitor C2, a battery management chip U2 and an output side connector CN4, and can output a 3V DC voltage. The utility model can construct a dual power supply system with 8-15V DC and 220V AC input, and a dual-channel charging system with 5V and 3V voltage outputs to provide charging for lithium batteries. The circuit structure is simple, circuit cost is saved, and the charging needs of common electronic products are met.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery charging, in particular to a simple 5V and 3V lithium battery charging system. Background Art

[0002] Lithium batteries are a type of battery that uses lithium metal or lithium alloy as positive / negative electrode materials and non-aqueous electrolyte solutions. With the development of science and technology, lithium batteries have become mainstream battery products. In daily life, electronic products such as mobile phones, tablets, and various types of toys often need to be powered by lithium batteries to ensure the normal operation of the above products and meet the needs of daily life.

[0003] At present, the working voltages of commonly used electronic products are more common at 5V and 3V, and most household power supplies are 220V AC power supplies (mains power), and some are 8-15V DC power supplies (output voltage of household photovoltaic panels) as household power supplies. Therefore, it is necessary to design a 5V and 3V lithium battery charging system with simple circuit structure and low cost for the above situation, which can be connected to the power supply system of 8-15V DC power supply and 220V AC power supply, and converted into 5V and 3V output voltages to meet the charging needs of lithium batteries. Utility Model Content

[0004] The purpose of the utility model is to overcome the defects and shortcomings of the prior art and to provide a simple 5V and 3V lithium battery charging system, which can construct a dual power supply system with 8-15V DC and 220V AC input and a dual charging system with 5V and 3V voltage output to provide charging for lithium batteries to meet the charging needs of commonly used electronic products.

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

[0006] A simple 5V and 3V lithium battery charging system, including a 5V lithium battery charging circuit and a 3V lithium battery charging circuit, characterized in that: the 5V lithium battery charging circuit includes an input side connector CN1, a protection diode D1, an energy storage capacitor EC1, a current limiting resistor R1, a voltage stabilizing chip U1, a diode D3, a transformer T1, a rectifier circuit, an input side connector CN2 and an output side connector CN2, the input end of the input side connector CN1 is externally connected to an 8-15V DC power supply, the input end of the input side connector CN2 is externally connected to a 220V AC power supply, the output end of the input side connector CN1 is connected to the protection diode D1, on the one hand, connected to the energy storage capacitor EC1 and then grounded, on the other hand, connected in sequence to the current limiting resistor R1, the voltage stabilizing chip U1 and the diode D3, and the output end of the input side connector CN2 is connected to the transformer T1 and the rectifier circuit in sequence, and then connected to the input end of the output side connector CN2, and a 5V DC voltage is output through the output end of the output side connector CN2;

[0007] The 3V lithium battery charging circuit includes a capacitor C2, a battery management chip U2 and an output side connector CN4. A wiring is led out from the input end of the output side connector CN2. On the one hand, it is connected to the capacitor C2 and then grounded. On the other hand, it is connected to the battery management chip U2 and then connected to the input end of the output side connector CN4. A 3V DC voltage is output through the output end of the output side connector CN2.

[0008] Furthermore, the GND port of the voltage regulator chip U1 is connected to the light emitting diode D2 and then grounded.

[0009] Furthermore, the rectifier circuit is a bridge rectifier circuit composed of diodes D4, D5, D6, and D7.

[0010] Furthermore, the two input ends of the bridge rectifier circuit are respectively connected to the two ends of the secondary coil of the transformer T1, and one output end of the bridge rectifier circuit is grounded. The other output end of the bridge rectifier circuit is connected to the input end of the output side connector CN2 on the one hand, and is connected to the current limiting resistor R2 and the light-emitting diode D8 in sequence on the other hand to be divided into two branches, one of which is connected to the light-emitting diode D9 and the current limiting resistor R3 in sequence, and the other branch is connected to the voltage divider resistor R4 and then converged into one place and connected to the PGND port of the output side connector CN2.

[0011] Furthermore, a voltage feedback resistor R5 is connected between the VCC port and the BAT port of the battery management chip U2.

[0012] Furthermore, a wiring is led out from the input end of the output side connector CN2, and then connected to the current limiting resistor R6 and divided into two branches, one of which is connected to the green LED light D10 and then grounded, and the other branch is connected to the red LED light D11 and then connected to the CHRG port of the battery management chip U2.

[0013] Furthermore, the on-state voltage drop of the green LED lamp D10 is 2.5V, and the on-state voltage drop of the red LED lamp D11 is 1.7V.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] The utility model can be connected to a power supply system of 8-15V DC power supply and 220V AC power supply, and can convert into output voltages of 5V and 3V, that is, a dual power supply system with 8-15V DC power and 220V AC power input is constructed, and a dual-path charging system with 5V and 3V voltage output is used to charge the lithium battery. The circuit structure is simple, the circuit cost is saved, and the charging needs of common electronic products are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a circuit structure schematic diagram of the utility model. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in 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.

[0018] See also Figure 1A simple 5V and 3V lithium battery charging system includes a 5V lithium battery charging circuit and a 3V lithium battery charging circuit. The 5V lithium battery charging circuit includes an input side connector CN1, a protection diode D1, an energy storage capacitor EC1, a current limiting resistor R1, a voltage stabilizing chip U1, a diode D3, a transformer T1, a rectifier circuit, an input side connector CN2 and an output side connector CN2. The input end of the input side connector CN1 is externally connected to a 12V DC power supply, and the input end of the input side connector CN2 is externally connected to a 220V AC power supply. After the output end of the input side connector CN1 is connected to the protection diode D1, it is connected to the energy storage capacitor EC1 and then to ground on the one hand, and is connected to the current limiting resistor R1, the voltage stabilizing chip U1 and the diode D3 in sequence on the other hand. The output end of the input side connector CN2 is connected to the transformer T1 and the rectifier circuit in sequence, and then connected to the input end of the output side connector CN2, and a 5V DC voltage is output through the output end of the output side connector CN2;

[0019] The 3V lithium battery charging circuit includes a capacitor C2, a battery management chip U2 and an output side connector CN4. A wiring is led out from the input end of the output side connector CN2. On the one hand, it is connected to the capacitor C2 and then grounded. On the other hand, it is connected to the battery management chip U2 and then connected to the input end of the output side connector CN4. A 3V DC voltage is output through the output end of the output side connector CN2.

[0020] In the present invention, the GND port of the voltage stabilizing chip U1 is connected to the light emitting diode D2 and then grounded.

[0021] Therefore, by providing the light emitting diode D2, on the one hand, it can be used as a power supply indicator light of the external DC power supply, and on the other hand, the output voltage can be raised by about 1V.

[0022] In the utility model, the rectifier circuit is a bridge rectifier circuit composed of diodes D4, D5, D6 and D7.

[0023] In the utility model, the two input ends of the bridge rectifier circuit are respectively connected to the two ends of the secondary coil of the transformer T1, and one output end of the bridge rectifier circuit is grounded. The other output end of the bridge rectifier circuit is connected to the input end of the output side connector CN2 on the one hand, and is connected to the current limiting resistor R2 and the light emitting diode D8 in sequence on the other hand, and then divided into two branches, one of which is connected to the light emitting diode D9 and the current limiting resistor R3 in sequence, and the other branch is connected to the voltage dividing resistor R4 and then converged into one place and connected to the PGND port of the output side connector CN2.

[0024] Therefore, the light emitting diode D8 is used as a power indicator light, and when it is lit, it indicates that input power is connected.

[0025] In addition, the LED D9 is used as a charging indicator light, which indicates that a 5V charging load is connected when it is lit. When the load is connected to the 5V charging interface, a voltage drop of about 3V is generated on the resistor R4, that is, a voltage drop of 3V is also generated across the resistor R3 and the LED D9, causing the LED D9 to turn on and light up.

[0026] In the present invention, a voltage feedback resistor R5 is connected between the VCC port and the BAT port of the battery management chip U2.

[0027] In the utility model, a wiring is led out from the input end of the output side connector CN2, and then connected to the current limiting resistor R6 and divided into two branches, one of which is connected to the green LED light D10 and then grounded, and the other branch is connected to the red LED light D11 and then connected to the CHRG port of the battery management chip U2.

[0028] In the present invention, the on-state voltage drop of the green LED lamp D10 is 2.5V, and the on-state voltage drop of the red LED lamp D11 is 1.7V.

[0029] The utility model is further described below in conjunction with the accompanying drawings:

[0030] The utility model uses 12V DC and 220V AC input as a dual power supply system and 5V voltage output as a charging system. The specific working process is as follows:

[0031] A 12V DC voltage is input through the input side connector CN1, and is powered by the voltage regulator chip (L7806) U1 through the protection diode (1N4007-M7) D1, the energy storage capacitor (100uF / 25V) EC1, and the current limiting resistor (36R-1206) R1. Since the GND port (ground port) of the voltage regulator chip U1 is grounded through the light-emitting diode (LED0805) D2, the output voltage of the voltage regulator chip U1 is stably adjusted to 7.8V, and then through the voltage divider effect of the resistor R4, the resistor R3 and the light-emitting diode D9, a 5V DC voltage is output through the output end of the output side connector CN2.

[0032] The 220V AC voltage is input through the input side connector CN3, which is reduced to an AC voltage of about 7V by the transformer T1, and then converted into a DC voltage of about 8V (i.e. 7V×1.414-1.7V≈8V, where 1.7V is the voltage drop of the bridge rectifier circuit) through the rectification effect of the bridge rectifier circuit composed of diodes D4, D5, D6, and D7, and then through the voltage division effect of resistors R4, R3 and light-emitting diode D9, and then outputs a 5V DC voltage through the output end of the output side connector CN2.

[0033] In addition, the resistor R2 is used as a current limiting resistor, the light emitting diode D8 is used as a power indicator light, and the light emitting diode D9 is used as a charging status indicator light.

[0034] The resistor R4 is used as a voltage-dividing resistor, and the resistor R3 is used as a current-limiting resistor. In the charging state, the resistor R4 bears a voltage drop of about 3V, and the light-emitting diode D9 is lit through the resistor R3. At this time, it indicates that the battery is in the charging state.

[0035] The utility model uses 12V DC and 220V AC input as a dual power supply system and 3V voltage output as a charging system. The specific working process is as follows:

[0036] The 5V DC voltage output by the above circuit charges the capacitor (10uF / 1206) C2, and then supplies it to the battery management chip (TP4054) U2. The resistor (100K-0603) R5 is used as a voltage feedback resistor to stabilize the output voltage of the battery management chip U2, and outputs a 3V DC voltage through the BAT port of the stabilized battery management chip U2, and then outputs a 3V DC voltage through the output end of the output side connector CN4.

[0037] In addition, the resistor (2K-0603) R6 serves as a current limiting resistor for the green LED lamp D10 and the red LED lamp D11, wherein the on-state voltage drop of the green LED lamp D10 is 2.5V, and the on-state voltage drop of the red LED lamp D11 is 1.7V. Therefore, when the output side connector CN4 is not connected to the lithium battery, that is, when charging is not performed, the CHRG port (pin 1) of the battery management chip U2 is set to a high level, and the red LED lamp D11 cannot be turned on, that is, cannot be lit. The current flows into the green LED lamp D10 through the resistor R6, so that the green LED lamp D10 is lit. At this time, it indicates that it is in an uncharged state; when the output side connector CN4 is connected to the lithium battery, that is, charging is performed, the CHRG port (pin 1) of the battery management chip U2 is grounded, so that the red LED lamp D11 is lit, and the green LED lamp D10 cannot be lit due to being bypassed. At this time, it indicates that it is in a charging state.

[0038] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0039] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent changes made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. A simple 5V and 3V lithium battery charging system, including a 5V lithium battery charging circuit and a 3V lithium battery charging circuit, characterized in that: The 5V lithium battery charging circuit includes an input side connector CN1, a protection diode D1, an energy storage capacitor EC1, a current limiting resistor R1, a voltage stabilizing chip U1, a diode D3, a transformer T1, a rectifier circuit, an input side connector CN2 and an output side connector CN2. The input end of the input side connector CN1 is externally connected to an 8-15V DC power supply, and the input end of the input side connector CN2 is externally connected to a 220V AC power supply. After the output end of the input side connector CN1 is connected to the protection diode D1, on the one hand, it is connected to the energy storage capacitor EC1 and then grounded, and on the other hand, it is sequentially connected to the current limiting resistor R1, the voltage stabilizing chip U1 and the diode D3. The output end of the input side connector CN2 is sequentially connected to the transformer T1 and the rectifier circuit, and then connected to the input end of the output side connector CN2, and a 5V DC voltage is output through the output end of the output side connector CN2; The 3V lithium battery charging circuit includes a capacitor C2, a battery management chip U2 and an output side connector CN4. A wiring is led out from the input end of the output side connector CN2. On the one hand, it is connected to the capacitor C2 and then grounded. On the other hand, it is connected to the battery management chip U2 and then connected to the input end of the output side connector CN4. A 3V DC voltage is output through the output end of the output side connector CN2.

2. A simple 5V and 3V lithium battery charging system according to claim 1, characterized in that: The GND port of the voltage stabilizing chip U1 is connected to the light emitting diode D2 and then grounded.

3. A simple 5V and 3V lithium battery charging system according to claim 1, characterized in that: The rectifier circuit is a bridge rectifier circuit composed of diodes D4, D5, D6 and D7.

4. A simple 5V and 3V lithium battery charging system according to claim 3, characterized in that: The two input ends of the bridge rectifier circuit are respectively connected to the two ends of the secondary coil of the transformer T1, and one output end of the bridge rectifier circuit is grounded. The other output end of the bridge rectifier circuit is connected to the input end of the output side connector CN2 on the one hand, and is connected to the current limiting resistor R2 and the light emitting diode D8 in sequence on the other hand, and then divided into two branches, one of which is connected to the light emitting diode D9 and the current limiting resistor R3 in sequence, and the other branch is connected to the voltage dividing resistor R4 and then converged into one place and connected to the PGND port of the output side connector CN2.

5. A simple 5V and 3V lithium battery charging system according to claim 1, characterized in that: A voltage feedback resistor R5 is connected between the VCC port and the BAT port of the battery management chip U2.

6. A simple 5V and 3V lithium battery charging system according to claim 1, characterized in that: A wiring is led out from the input end of the output side connector CN2, and then connected to the current limiting resistor R6 and divided into two branches, one of which is connected to the green LED light D10 and then grounded, and the other branch is connected to the red LED light D11 and then connected to the CHRG port of the battery management chip U2.

7. A simple 5V and 3V lithium battery charging system according to claim 6, characterized in that: The on-state voltage drop of the green LED lamp D10 is 2.5V, and the on-state voltage drop of the red LED lamp D11 is 1.7V.

Images