A lithium battery charging protection circuit

Abstract

The utility model discloses a lithium battery charging protection circuit belongs to lithium battery charging management technical field. The circuit board has integrated ten independent lithium battery charging channels, and each group channel adopts PW4203 charging management chip, realizes the constant current constant voltage charging control of single lithium battery. Each group channel is equipped with input filter circuit, charging state indicating circuit and NTC temperature interface, and the stability and visibility of charging process are ensured. In order to enhance the battery safety protection function, the output end of each group channel is further configured with a group of protection circuit composed of DW01 protection chip and 8205 double MOS tube, and is used for the automatic protection of overcharge, overdischarge, overcurrent and short circuit and other abnormal states to the battery. The channel structure is independent of each other but is integrated on the same circuit board, and the overall layout is compact, the management efficiency is high, and is suitable for lithium battery batch charging scene. The circuit board has the advantages of stable charging performance, perfect protection function and the like, and improves the safety and practicality of the charging system.

Description

Technical Field

[0001] This utility model relates to a lithium battery charging protection circuit, belonging to the field of lithium battery charging management technology. Background Technology

[0002] With the rapid development of portable devices, power tools, energy storage systems, and mobile power supplies, lithium-ion batteries have become the mainstream energy storage medium due to their high energy density, long cycle life, and superior charge-discharge performance. In multi-cell applications or batch battery testing, parallel charging and management of multiple lithium batteries is often required to improve efficiency and system integration. Therefore, designing a compact, channel-independent, safe, and reliable multi-channel lithium battery charging system has become a practical need in the industry.

[0003] Existing lithium battery charging circuits generally employ integrated charging management chips, such as TP4056, CN3703, and PW4203, to achieve basic constant current and constant voltage charging control. However, these existing technologies have the following shortcomings:

[0004] Weak channel expansion capability and low integration: Most traditional charging modules are single-channel structures. When multiple channels of charging are required, multiple single-board modules are usually spliced ​​together, resulting in large system size, complex wiring, and difficult maintenance.

[0005] Lack of comprehensive battery protection functions: Some modules do not integrate battery protection circuits, and cannot cut off the circuit in time in case of overcharging, over-discharging, or abnormal current of lithium batteries, which poses a significant safety hazard.

[0006] Therefore, it is necessary to provide a multi-channel lithium battery charging circuit board with high integration, stable charging, independent controllability of each channel, and complete protection mechanism to meet the practical application requirements of multi-cell synchronous charging, safety monitoring, and high reliability management. Utility Model Content

[0007] The purpose of this invention is to provide a lithium battery charging protection circuit that can effectively solve the above-mentioned problems.

[0008] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0009] The circuit board includes ten independent charging unit circuits integrated on it, each of which includes:

[0010] The input port VCC is connected to the input filter capacitor bank via a Schottky diode; the filter capacitor bank is connected to the VIN pin of the PW4203 chip.

[0011] The BAT pin of the PW4203 chip is connected to the output filter capacitor and the boost inductor. A current sampling resistor is connected in series after the boost inductor and together they are connected to the battery output terminal BAT. The LX pin of the PW4203 chip is connected to the boost inductor. The PROG pin of the PW4203 chip uses the default charging current configuration. The VSET pin of the PW4203 chip is grounded, and the TCCT pin is grounded through a timing capacitor. The NTC pin is connected to a thermistor. The STAT pin is connected to an LED indicator circuit to display the charging status. Each charging unit circuit has an independent output port, including BAT, NTC, and GND interfaces.

[0012] Furthermore, the ten sets of charging unit circuits are arranged in a regular array on the circuit board, with each set of circuits not interfering with each other and sharing the same input power supply VCC and ground GND.

[0013] Furthermore, the PW4203 chip used in each of the charging unit circuits operates in boost mode, supporting constant current and constant voltage charging of a single lithium battery.

[0014] Furthermore, the boost inductor of each charging unit circuit has an inductance of 6.8μH and a sampling resistor of 15mΩ.

[0015] Furthermore, each PW4203 chip has a red LED and a current-limiting resistor connected to its STAT pin to display the charging status of each battery in real time.

[0016] Furthermore, the NTC pin of each PW4203 chip is connected to VCC via a pull-up resistor and is brought out for connecting an external thermistor to detect battery temperature.

[0017] Furthermore, each of the charging unit circuits is provided with a charging protection unit, which includes a protection chip DW01A, a dual N-channel MOSFET 8205, a pull-up resistor, and a filter capacitor.

[0018] Furthermore: the VCC pin of the protection chip DW01A is connected to the positive terminal of the battery, and the GND pin is connected to the negative terminal of the battery; the source and drain of the dual N-channel MOSFET are connected back-to-back on the negative terminal path of the battery.

[0019] Furthermore, the OD and OC pins of the protection chip DW01A are respectively connected to the two gates of the dual N-channel MOSFET, and the gates are driven stably by pull-up resistors and capacitors.

[0020] The beneficial effects are:

[0021] It adopts ten independent charging unit circuits, each of which integrates a PW4203 lithium battery charging chip, enabling simultaneous charging and independent management of ten individual lithium batteries, which facilitates large-scale battery testing and batch pre-charging applications.

[0022] All charging units are integrated on the same circuit board, sharing the input power and ground wire, which reduces the wiring mess caused by module splicing and improves the overall system integration and maintainability.

[0023] Each channel uses a PW4203 boost-type charging management chip, which supports constant current and constant voltage control, has high charging efficiency and thermal management capabilities, and is suitable for various application environments.

[0024] Each charging unit's output terminal integrates a protection module consisting of a DW01 battery protection chip and 8205 dual MOSFETs, which can provide overvoltage, undervoltage, overcurrent, and short circuit protection for the battery, effectively preventing battery damage or safety accidents.

[0025] Clear status indication and easy monitoring: Each charging circuit is equipped with an LED status indicator to display the charging status in real time. Combined with the NTC thermistor interface, the battery temperature can be monitored, improving safety and visibility during use. Attached Figure Description

[0026] For ease of explanation, this utility model is described in detail below with reference to the specific embodiments and accompanying drawings.

[0027] Figure 1 This is a circuit diagram of a charging path for this utility model;

[0028] Figure 2 This is a circuit diagram of the charging protection unit of this utility model;

[0029] Figure 3 This is a circuit diagram of the five charging paths of this utility model. Detailed Implementation

[0030] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] Furthermore, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] See Figure 1-3 This invention relates to an embodiment of a lithium battery charging protection circuit, comprising ten independent charging paths. Each circuit uses a PW4203 lithium battery charging management chip to achieve constant current and constant voltage charging control for a single lithium battery.

[0033] Taking the first charging circuit as an example, as shown in the attached diagram, the input terminal of the charging circuit is VCC. First, a Schottky diode (model SS34) is used to realize the reverse connection protection function of the power supply. Then, three filter capacitors are connected in sequence: electrolytic capacitor C41 (100μF), surface mount capacitor C1 (22μF), and ceramic capacitor C2 (0.1μF) to suppress input voltage fluctuations and improve power supply stability.

[0034] The VIN pin of the PW4203 chip is connected to the filtered input power supply, and the GND pin is grounded. The STAT pin of the chip is connected to the power supply through a series resistor (R2, 1kΩ) and an LED (LED1, 0603 red) to indicate the charging status of the current channel. When STAT is low, the LED lights up, indicating that it is charging.

[0035] The TCCT pin of the chip is connected to an external timing capacitor C4 (470nF) and grounded to set the charging timeout protection time during the constant voltage stage. The VSET pin is grounded to set the output voltage to 4.2V, which is compatible with common single-cell lithium batteries.

[0036] The chip's PROG pin uses the default charging current configuration, with a typical selection value set to around 1A (e.g., setting it to 2kΩ will result in a charging current of approximately 1A, which can be adjusted according to the PW4203 datasheet). The chip's NTC pin is connected to VCC via a pull-up resistor (R1, 10kΩ) and an NTC1 interface is provided for connecting a battery thermistor to achieve temperature detection and protection functions.

[0037] The LX pin of the PW4203 chip is connected to a boost inductor L1 (6.8μH). The output of this inductor is connected in series with a current sensing resistor R3 (15mΩ) and then connected to the BAT output port. A filter capacitor C3 (22μF) is connected in parallel to the BAT output port to stabilize the output.

[0038] The first charging circuit outputs all have three-terminal interfaces J1, including BAT1 (battery positive), NTC1 (temperature feedback), and GND (ground). Each set of interfaces corresponds to one set of battery connections, and the ten sets of interfaces can simultaneously manage and charge ten single lithium batteries independently.

[0039] The ten circuits of this invention are evenly arranged in a matrix on a PCB board. The circuits are independent of each other but share the input VCC and the common ground GND, which greatly improves the space utilization of the circuit board and facilitates batch management, testing and assembly.

[0040] This multi-channel charging circuit board is suitable for parallel charging scenarios of multiple lithium batteries, such as portable battery pack pre-charging platforms, power tool battery pack charging stations, and battery aging test stations. It has the advantages of compact structure, stable charging, status visualization, and temperature control protection.

[0041] In each of the above-mentioned charging unit circuits, this embodiment further includes a charging protection unit for overvoltage, undervoltage, overcurrent and short circuit protection of the lithium battery. This module consists of a lithium battery protection chip DW01 and dual MOS transistors 8205.

[0042] The DW01 chip is used to monitor the voltage and current of a connected single lithium battery in real time. Its power supply pin VDD is connected to the positive terminal of the battery, and its VSS pin is connected to the negative terminal of the battery. The OD and OC pins of the DW01 chip control the gate of the dual N-channel MOSFET 8205, respectively, to control the conduction state of the discharge path (OD) and the charge path (OC).

[0043] The 8205 is an integrated dual N-channel MOSFET. Its source is connected to the negative terminal of the battery, and its drain is connected to the system load terminal and the negative terminal of the charger, respectively, forming the forward / reverse conduction control path of the battery. When DW01 detects any of the following conditions, it will turn off the MOSFET: if the battery voltage exceeds the overcharge threshold, the charging path will be cut off; if the battery voltage is lower than the over-discharge threshold, the discharge path will be cut off; if an abnormal current is detected, such as a short circuit or overcurrent, the circuit will be immediately disconnected to protect the battery.

[0044] The DW01 and 8205 modules are located between the output of the PW4203 chip and the battery BAT interface, forming a complete dual safety architecture of "charging control + battery protection". This structure can ensure that the voltage and current are controlled during the charging process, and prevent the battery from being damaged under extreme conditions.

[0045] Each charging unit circuit is equipped with an independent DW01+8205 protection module, thereby achieving independent safety protection for each battery, which is suitable for the high safety requirements of large-scale battery pack management systems.

[0046] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A lithium battery charging protection circuit, characterized in that: The circuit board includes ten independent charging unit circuits integrated on it, each of which includes: The input port VCC is connected to the input filter capacitor bank via a Schottky diode; the filter capacitor bank is connected to the VIN pin of the PW4203 chip. The BAT pin of the PW4203 chip is connected to the output filter capacitor and the boost inductor. A current sampling resistor is connected in series after the boost inductor and together they are connected to the battery output terminal BAT. The LX pin of the PW4203 chip is connected to the boost inductor. The PROG pin of the PW4203 chip uses the default charging current configuration. The VSET pin of the PW4203 chip is grounded, and the TCCT pin is grounded through a timing capacitor. The NTC pin is connected to a thermistor. The STAT pin is connected to an LED indicator circuit to display the charging status. Each charging unit circuit has an independent output port, including BAT, NTC, and GND interfaces.

2. The lithium battery charging protection circuit according to claim 1, characterized in that: The ten sets of charging unit circuits are arranged in a regular array on the circuit board. Each set of circuits does not interfere with the others and shares the same input power supply VCC and ground GND.

3. The lithium battery charging protection circuit according to claim 2, characterized in that: The PW4203 chip used in each of the charging unit circuits operates in boost mode, supporting constant current and constant voltage charging of a single lithium battery.

4. The lithium battery charging protection circuit according to claim 3, characterized in that: The boost inductor of each charging unit circuit has an inductance of 6.8μH and a sampling resistor of 15mΩ.

5. The lithium battery charging protection circuit according to claim 4, characterized in that: Each PW4203 chip has a red LED and a current-limiting resistor connected to its STAT pin to display the charging status of each battery in real time.

6. The lithium battery charging protection circuit according to claim 5, characterized in that: The NTC pin of each PW4203 chip is connected to VCC via a pull-up resistor and is brought out for connecting an external thermistor to detect battery temperature.

7. The lithium battery charging protection circuit according to claim 1, characterized in that: Each of the charging unit circuits is equipped with a charging protection unit, which includes a protection chip DW01A, a dual N-channel MOSFET 8205, a pull-up resistor, and a filter capacitor.

8. The lithium battery charging protection circuit according to claim 7, characterized in that: The VCC pin of the protection chip DW01A is connected to the positive terminal of the battery, and the GND pin is connected to the negative terminal of the battery; the source and drain of the dual N-channel MOSFET are connected back-to-back in the negative terminal path of the battery. Furthermore, the OD and OC pins of the protection chip DW01A are respectively connected to the two gates of the dual N-channel MOSFET, and the gates are driven stably by pull-up resistors and capacitors.

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