An automatic identification battery pack multi-voltage output charger

Abstract

The utility model discloses a kind of multi-voltage output charger of automatic identification battery pack, comprising: sequentially electrically connected power input module, power conversion module and output module, and a control module.Control module reads the level of battery pack identity recognition pin by its ID detection circuit, judges battery pack type by MCU, and then controls output control circuit to select corresponding output voltage passage, realizes conduction with charging interface.The utility model realizes the automatic identification and adaptive charging of different voltage grade battery pack by hardware circuit structure, overcomes the drawbacks of needing special charger or manual switching in prior art, with the advantages of convenient to use, safe and reliable.

Description

Technical Field

[0001] This utility model relates to the field of electronic charging equipment technology, and in particular to a multi-voltage output charger that automatically identifies battery packs. Background Technology

[0002] In fields such as power tools, lithium-ion battery packs come in various specifications due to differences in voltage and capacity, such as the common 20V and 40V battery packs. Currently, users typically need to equip themselves with dedicated chargers for different battery pack specifications, which increases user costs and inconvenience. Some chargers attempt to allow users to manually switch the output voltage via an internal switch, but this method carries the risk of misoperation, potentially damaging the battery pack or charger. The root cause is that existing chargers lack a mechanism in their circuit structure that can automatically and accurately identify the battery pack type and adjust the output circuit accordingly. Therefore, the market urgently needs a charger that can automatically identify the battery pack type and output the corresponding voltage to solve the problems and risks associated with users needing to prepare multiple dedicated chargers or manually switch between them. Utility Model Content

[0003] To address the problems of inconvenience, risk of misoperation, and high cost caused by the inability of existing chargers to automatically identify battery pack types, this utility model proposes a multi-voltage output charger that automatically identifies battery packs.

[0004] The specific technical solution is as follows:

[0005] A multi-voltage output charger that automatically identifies battery packs includes: a power input module, a power conversion module, and an output module connected in sequence, wherein the output module includes a charging interface and a control module;

[0006] The control module includes a microcontroller unit (MCU), an ID detection circuit, and an output control circuit.

[0007] The input terminal of the ID detection circuit is electrically connected to the identity recognition pin of the charging interface, and the output terminal of the ID detection circuit is electrically connected to the analog-to-digital conversion sampling pin of the MCU.

[0008] The input terminal of the output control circuit is electrically connected to the output terminal of the power conversion module, and the control terminal of the output control circuit is electrically connected to at least one control pin of the MCU. The output terminal of the output control circuit has multiple power supply paths corresponding to different output voltages and is selectively electrically connected to the power output pin of the charging interface. Through the hardware connection between the ID detection circuit and the MCU, and the multi-output selection structure of the output control circuit, automatic identification and adaptation of the battery pack type is achieved at the hardware level. Users do not need to manually switch or prepare multiple chargers, improving the convenience and safety of use and fundamentally avoiding the risk of equipment damage due to misoperation.

[0009] Furthermore, the power conversion module includes a transformer, a PWM control chip, and a first MOSFET;

[0010] The primary winding of the transformer is connected to the output of the rectifier and filter circuit through the first MOS transistor;

[0011] The control electrode of the first MOSFET is electrically connected to the gate drive pin of the PWM control chip;

[0012] The auxiliary winding of the transformer is electrically connected to the power supply pin of the PWM control chip through a rectifier and filter element. This structure achieves efficient and stable power conversion and electrical isolation. At the same time, by powering the PWM chip through the auxiliary winding, it ensures the reliability of the self-powered control circuit and makes the system work more stably.

[0013] Furthermore, the ID detection circuit includes a pull-up resistor. One end of the pull-up resistor is connected to a reference voltage source, and the other end is connected to both the identification pin of the charging interface and the analog-to-digital conversion sampling pin of the MCU. Different battery pack types can be accurately distinguished using a single pull-up resistor and the MCU's AD sampling function, achieving a cost-effective identification solution.

[0014] Furthermore, the output control circuit includes multiple electronic switches connected in parallel. The control terminals of these electronic switches are electrically connected to the control pins of the MCU. The output terminals of the multiple electronic switches correspond to different output voltages and are all connected to a main power supply circuit of the output module. By connecting multiple electronic switches in parallel on a main power supply circuit and controlling their time-sharing conduction by the MCU, multiple output voltages can be generated using a single power conversion and output circuit. The circuit structure is compact, avoiding the complexity and cost of building independent circuits for each voltage, while retaining the advantages of electronic switches such as fast response, no wear, and long lifespan.

[0015] Furthermore, the output module also includes an anti-backflow circuit, which is connected in series between the output control circuit and the power output pin of the charging interface. This effectively prevents the battery pack current from flowing back into the charger's internal circuitry, protecting sensitive components inside the charger and improving the reliability and safety of the entire system.

[0016] Furthermore, the anti-backflow circuit includes a second MOSFET, the source and drain of which are connected in series in the output positive circuit, and its gate is electrically connected to a drive signal. Utilizing the unidirectional conduction characteristic and low on-resistance of the MOSFET, efficient power transfer and reliable anti-backflow function are achieved. Its low power consumption contributes to improved charging efficiency.

[0017] Furthermore, it also includes a current sampling and amplification circuit, which comprises a sampling resistor and an operational amplifier connected in series in the output circuit. The input terminal of the operational amplifier is connected across the sampling resistor, and the output terminal of the operational amplifier is electrically connected to the analog input pin of the MCU. This allows for real-time and accurate monitoring of the charging current, providing accurate feedback signals to the MCU, facilitating advanced charging management functions such as constant current charging and overcurrent protection, and ensuring battery charging safety and lifespan.

[0018] Furthermore, it also includes fan control circuitry and temperature detection circuitry;

[0019] The temperature detection circuit includes a thermistor connected between a reference voltage and ground, and the voltage divider node of the thermistor is electrically connected to the analog input pin of the MCU.

[0020] The fan control circuit includes a driving transistor, the base of which is electrically connected to the control pin of the MCU through a resistor. Its collector-emitter circuit is connected in series in the fan's power supply circuit. This enables real-time monitoring and intelligent heat dissipation of the charger's operating temperature. When the temperature is too high, the fan automatically starts, effectively preventing damage to the charger due to overheating and improving the reliability of the product during long-term operation in high-temperature environments.

[0021] Furthermore, the power input module includes an EMI filter circuit and a rectifier bridge;

[0022] The input terminal of the EMI filter circuit is connected to the mains power, and the output terminal of the EMI filter circuit is electrically connected to the AC input terminal of the rectifier bridge.

[0023] The DC output terminal of the rectifier bridge is electrically connected to the power conversion module. The EMI filter circuit can effectively suppress interference from the power grid and electromagnetic pollution from the charger itself to the power grid, while the rectifier bridge converts AC mains power into DC power, providing a clean and stable DC power supply for subsequent power conversion.

[0024] Furthermore, the power conversion module also includes an RCD spike absorption circuit connected across the primary winding of the transformer. This effectively absorbs the reverse peak voltage generated in the primary winding of the transformer when the first MOSFET is turned off, preventing the first MOSFET from being damaged and significantly improving the reliability and lifespan of the power conversion module.

[0025] The above technical solution has the following advantages or technical effects:

[0026] 1. This utility model automatically identifies the battery pack type and switches the output through hardware circuit structure, realizing "one machine for multiple uses", which greatly improves the convenience of user use and the versatility of the product. The circuit structure is clear and modular design, which ensures the feasibility of production and cost controllability while realizing complex functions.

[0027] 2. This utility model constructs multiple safety protection mechanisms by introducing anti-backflow circuits, current sampling and temperature monitoring structures, which significantly improves the safety and reliability of the charging process.

[0028] 3. This utility model adopts a high-efficiency switching power supply architecture combined with intelligent heat dissipation management, which realizes high-efficiency power conversion and good thermal performance, ensuring that the charger can work stably for a long time. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of this utility model;

[0030] Figure 2 This is a schematic diagram of the power input module of this utility model;

[0031] Figure 3 This is a schematic diagram of the power conversion module of this utility model;

[0032] Figure 4 This is the schematic diagram of the microcontroller unit (MCU) of this utility model;

[0033] Figure 5 This is a schematic diagram of the ID detection circuit of this utility model;

[0034] Figure 6 This is a schematic diagram of the anti-backflow circuit of this utility model;

[0035] Figure 7 This is a schematic diagram of the output module of this utility model;

[0036] Figure 8 This is the schematic diagram of the TL431 sampling circuit and multi-output control circuit of this utility model;

[0037] Figure 9 This is a schematic diagram of the temperature detection circuit of this utility model;

[0038] Figure 10 This is a schematic diagram of the fan control circuit of this utility model. Detailed Implementation

[0039] To make the technical solution of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, a multi-voltage output charger that automatically identifies battery packs achieves automatic identification of battery pack types and multi-voltage output switching through a hardware circuit structure. It includes a power input module, a power conversion module, an output module, and a control module, all electrically connected sequentially. The control module reads the battery pack identification information through an ID detection circuit, and the microcontroller unit (MCU) controls the output control circuit based on this information to select the appropriate output voltage path, thereby achieving automatic adaptive charging for battery packs of different specifications (such as 20V or 40V).

[0041] like Figure 2 As shown, the power input module includes a fuse F1, an EMI filter circuit, and a rectifier bridge BD1. The AC input passes sequentially through the fuse F1 and the EMI filter circuit (composed of a common-mode inductor LF1, filter capacitors CX1 and CX2, etc.) before being connected to the AC input terminal of the rectifier bridge BD1. The EMI filter circuit suppresses electromagnetic interference, ensuring stable charger operation and compliance with electromagnetic compatibility standards. The DC output terminal of the rectifier bridge BD1 outputs pulsating DC power, which is smoothed and filtered by the filter capacitor EC1A to generate approximately 310V DC high voltage (HV_310V), powering the subsequent power conversion module. This module provides a clean and stable DC power supply to the system through EMI filtering and rectification, effectively reducing interference to the power grid and improving the reliability of the charger.

[0042] like Figure 3As shown, the power conversion module adopts a flyback switching power supply structure, including a transformer T1, a PWM control chip IC4 (model LN3C60), a first MOSFET Q1, and an RCD peak absorption circuit. The rectified and filtered DC high voltage HV_310V is connected to the primary winding of transformer T1, which is connected to hot ground through the first MOSFET Q1. The Gate pin (pin 1) of the PWM control chip IC4 outputs a square wave signal to control the on / off state of the first MOSFET Q1. When the first MOSFET Q1 is on, energy is stored in the primary winding of transformer T1; when it is off, the primary energy is released to the secondary winding and auxiliary winding. The auxiliary winding, after rectification by diode D3 and filtering by capacitor EC3, provides operating power to the VCC pin (pin 4) of the PWM control chip IC4, achieving self-powered operation. The RCD peak absorption circuit is connected across the primary winding of transformer T1 to absorb the reverse peak voltage generated when the first MOSFET Q1 is turned off, preventing the first MOSFET Q1 from breaking down. This module achieves high-efficiency power conversion and electrical isolation, and protects the power switching transistors through the RCD circuit, thereby improving system lifespan and stability.

[0043] The control module includes, for example: Figure 4 The microcontroller unit (MCU, U1, model MC51F003A4), ID detection circuit, and output control circuit shown are as follows:

[0044] ID detection circuit: This circuit includes a pull-up resistor R210, one end of which is connected to the 5V reference voltage source provided by the MCU U1, and the other end is connected to the ID pin of the charging interface P1 and the analog-to-digital conversion sampling pin of the MCU U1 (e.g., P2.2 / AIN00). When the battery pack is inserted into the charging interface P1, the pull-down resistor inside the battery pack and the pull-up resistor R210 form a voltage divider, such as... Figure 5 As shown, MCU U1 can determine the battery pack type (e.g., 20V or 40V) and the required charging current by sampling the voltage divider value using an AD converter. This circuit has a simple structure and low cost, achieving accurate identification of the battery pack and providing a reliable basis for subsequent output control.

[0045] Output control circuit: This circuit adopts a parallel switching structure, including multiple electronic switches, such as MOSFETs Q2B and Q2C (model NCEP50P06). The sources (or drains) of these MOSFETs are all connected to the main power supply circuit output by the power conversion module, while the drains (or sources) are respectively connected to the feedback network that determines the output voltage or different winding taps of the switching power supply (the specific circuit depends on the design, for example, by controlling different switch combinations to change the feedback voltage division ratio or the secondary winding connected). The control electrodes (gates) of these MOSFETs are electrically connected to the control pins of MCU U1. Based on the ID detection result, MCU U1 outputs a control signal to enable the corresponding electronic switch, thereby switching the main power supply circuit to the corresponding output voltage. This parallel shared main circuit structure significantly simplifies transformer design and the number of power components compared to establishing completely independent power channels for each voltage.

[0046] The output module includes an output rectifier and filter circuit and an anti-backflow circuit, such as... Figure 6 As shown. The output voltage of the secondary winding of transformer T1 is rectified by rectifier diode D2 and filtered by filter capacitors EC7 and EC8, as follows. Figure 7 As shown, the DC voltage is obtained. This DC voltage serves as the main power supply circuit. Subsequent precise voltage control and path selection are accomplished collaboratively by the output control circuit and the feedback network. The output voltage is precisely set and switched by controlling the resistor network connected in parallel in the feedback loop.

[0047] Specifically, the output control circuit includes a logic control network composed of transistors Q5, Q5A, and Q8, which controls the on / off state of power MOSFETs Q2B and Q2C, and simultaneously switches the parallel resistor combination in the TL431 reference circuit, such as... Figure 8 As shown.

[0048] 20V Output Mode: When a 20V output is required, the MCU controls transistor Q5 to turn on while ensuring Q5A is turned off. The conduction of Q5 causes resistors R27A and R27B to form a series connection, which in turn forms a parallel connection with fixed resistors R38 and R39A in the TL431 reference circuit. This changes the voltage division ratio of the entire feedback network, bringing the TL431's reference point to 2.5V, ultimately resulting in a stable 20V output. In this mode, power MOSFETs Q2B and Q2C are simultaneously controlled to turn on, forming a 20V charging path.

[0049] 40V Output Mode: When a 40V output is required, the MCU controls transistor Q5A to turn on while ensuring Q5A remains off. The conduction of Q5A causes resistors R27C and R27D to be connected in parallel, which in turn is connected in parallel with fixed resistors R38 and R39A, forming another voltage division ratio. This also stabilizes the TL431 reference point at 2.5V, but the final output is 40V. In this mode, power MOSFETs Q2B and Q2C are simultaneously controlled to turn on, forming a 40V charging path.

[0050] The reverse current protection function is implemented by power MOSFETs Q2B and Q2C. When the charger is not working or the MCU controls the transistor Q8 to turn off, Q8 will force the gate drive signals of Q2B and Q2C to fail, ensuring that both Q2B and Q2C are in the off state, thereby completely cutting off the output positive circuit and effectively preventing the current from the battery pack from flowing back into the charger.

[0051] By combining a sophisticated parallel resistor switching network with a single TL431 feedback reference circuit, multiple stable output voltages can be generated using the same power conversion and rectification / filtering circuitry. This method features a compact circuit structure, low cost, reliable control logic, and efficient reverse current protection through the power MOSFET itself.

[0052] The current sampling and amplification circuit (not shown in the figure) includes a sampling resistor RS1 (0.03Ω) and operational amplifiers IC2A and IC2B (LM358). The sampling resistor RS1 is connected in series in the output circuit, and the input terminals of the operational amplifiers are connected across RS1, amplifying the sampled voltage and outputting it to the analog input pin of MCU U1 (e.g., P1.5 / AIN08). MCU U1 monitors the charging current in real time based on this signal and compares it with a reference value to achieve constant current charging or overcurrent protection. This circuit provides accurate current feedback, making the charging process safer and more controllable, and extending the battery pack's lifespan.

[0053] like Figure 9 As shown, the temperature detection circuit includes a thermistor RT1 (100K), connected between a 5V reference voltage and ground. Its voltage divider node is electrically connected to the analog input pin (e.g., P2.1 / AIN00) of MCU U1. MCU U1 obtains the temperature value through AD sampling. Figure 10 As shown, the fan control circuit includes a driver transistor Q11 (model D882), whose base is electrically connected to the control pin of MCU U1 (e.g., P1.6 / TX1) via resistor R89. The collector-emitter loop is connected in series in the power supply circuit of fan FAN1. When the temperature exceeds a set threshold, MCU U1 outputs a signal to enable the driver transistor Q11, activating the fan for heat dissipation. This circuit achieves real-time temperature monitoring and intelligent heat dissipation, preventing the charger from overheating and ensuring stability during long-term operation.

[0054] When the battery pack is inserted into charging port P1, the ID detection circuit first reads the battery pack's identity information, and the MCU U1 determines the battery pack type (e.g., 20V or 40V) based on the AD sampling value. Subsequently, the MCU U1 controls the corresponding electronic switch in the output control circuit to turn on, selecting the corresponding output voltage path. Simultaneously, the current sampling circuit monitors the charging current in real time, the temperature detection circuit monitors the charger temperature, and activates the fan when necessary. Throughout the process, the anti-backflow circuit ensures unidirectional current flow, protecting the charger's safety. This invention, through the coordinated operation of the above hardware circuit structure, achieves automatic battery pack type identification, intelligent switching between multiple voltage outputs, and multiple safety protections. The overall structure is compact and functionally complete, effectively solving the problems of poor charger compatibility and inconvenience in existing technologies.

[0055] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A multi-voltage output charger that automatically identifies a battery pack, characterized by, It includes: a power input module, a power conversion module, and an output module connected in sequence, wherein the output module includes a charging interface and a control module; The control module includes a microcontroller unit (MCU), an ID detection circuit, and an output control circuit. The input terminal of the ID detection circuit is electrically connected to the identity recognition pin of the charging interface, and the output terminal of the ID detection circuit is electrically connected to the analog-to-digital conversion sampling pin of the MCU. The input terminal of the output control circuit is electrically connected to the output terminal of the power conversion module, and the control terminal of the output control circuit is electrically connected to at least one control pin of the MCU. The output terminal of the output control circuit has multiple power supply paths corresponding to different output voltages and is selectively electrically connected to the power output pin of the charging interface.

2. The multi-voltage output charger of claim 1, wherein, The power conversion module includes a transformer, a PWM control chip, and a first MOSFET; The primary winding of the transformer is connected to the output of the rectifier and filter circuit through the first MOS transistor; The control electrode of the first MOSFET is electrically connected to the gate drive pin of the PWM control chip; The auxiliary winding of the transformer is electrically connected to the power pin of the PWM control chip through a rectifier and filter element.

3. The multi-voltage output charger of claim 1, wherein, The ID detection circuit includes a pull-up resistor. One end of the pull-up resistor is connected to a reference voltage source, and the other end is connected to the identity recognition pin of the charging interface and the analog-to-digital conversion sampling pin of the MCU.

4. The multi-voltage output charger of claim 1, wherein, The output control circuit includes multiple electronic switches connected in parallel. The control electrode of each electronic switch is electrically connected to the control pin of the MCU. The output terminals of the multiple electronic switches correspond to different output voltages and are all connected to a main power supply circuit of the output module.

5. The multi-voltage output charger of claim 1, wherein, The output module also includes an anti-backflow circuit, which is connected in series between the output control circuit and the power output pin of the charging interface.

6. The multi-voltage output charger of claim 5, wherein, The backflow prevention circuit includes a second MOS transistor, the source and drain of which are connected in series in the output positive circuit, and its gate is electrically connected to a drive signal.

7. The multi-voltage output charger of claim 1, wherein, It also includes a current sampling and amplification circuit, which includes a sampling resistor and an operational amplifier connected in series in the output circuit. The input terminal of the operational amplifier is connected across the two ends of the sampling resistor, and the output terminal of the operational amplifier is electrically connected to the analog input pin of the MCU.

8. The multi-voltage output charger of claim 1, wherein, It also includes a fan control circuit and a temperature detection circuit; The temperature detection circuit includes a thermistor connected between a reference voltage and ground, and the voltage divider node of the thermistor is electrically connected to the analog input pin of the MCU. The fan control circuit includes a driving transistor. The base of the driving transistor is electrically connected to the control pin of the MCU through a resistor, and its collector-emitter circuit is connected in series in the power supply circuit of the fan.

9. The multi-voltage output charger of claim 1, wherein, The power input module includes an EMI filter circuit and a rectifier bridge; The input terminal of the EMI filter circuit is connected to the mains power, and the output terminal of the EMI filter circuit is electrically connected to the AC input terminal of the rectifier bridge. The DC output terminal of the rectifier bridge is electrically connected to the power conversion module.

10. The multi-voltage output charger of claim 2, wherein, The power conversion module also includes an RCD spike absorption circuit connected to both ends of the primary winding of the transformer.

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