A fast plug-in / plug-out detection circuit

Abstract

This utility model relates to the field of rechargeable lithium battery charging detection technology, and discloses a fast plug-in detection circuit. Its core includes a charging activation circuit composed of a charger voltage input terminal C+, a diode D1, a capacitor C1, resistors R3, R5, and R6, and a MOSFET Q2. The capacitance of capacitor C1 can be flexibly adjusted according to the required activation signal pulse width. During operation, the charger voltage input terminal C+ charges capacitor C1. The charging current flows through resistor R6, generating a voltage drop that drives MOSFET Q2 to conduct, and the activation signal output terminal outputs an activation signal. After capacitor C1 is fully charged, there is no current or voltage drop in resistor R6, MOSFET Q2 is turned off, the activation signal stops outputting, and the circuit remains in a no-signal state even when C+ is continuously supplying power. This circuit can accurately respond to the charger connection signal, ensuring reliable activation of the already powered battery. It features a simple structure, low cost, and high stability, effectively improving product charging reliability and user experience.

Description

Technical Field

[0001] This application belongs to the field of rechargeable lithium battery technology, specifically relating to a fast plug-in / plug-out detection circuit. Background Technology

[0002] During the charging process, rechargeable lithium battery products often experience poor contact between the AC plug and socket, or between the DC plug and the charging port socket. This manifests as sparking, multiple intermittent disconnections, or repeated on / off cycles with multiple connections and disconnections within a short period of time when the plug is inserted.

[0003] In the aforementioned scenarios of poor contact, even if the plug and socket are subsequently connected securely, the lithium battery's battery management system (BMS) may still fail to effectively detect the charger's connection signal. For batteries that have been powered off, they cannot be activated to start the charging process because the charger connection is not detected. If users do not pay attention to the charging indicator, they may mistakenly believe that the battery is charging normally, only to find out when they try to use the product that it is not actually charging. This issue can raise questions about the product's reliability and ease of use.

[0004] In response to the market feedback mentioned above, the product manufacturer raised the following requirement: the BMS needs to be able to quickly respond to various intermittent voltage signals when the charger is connected, ensuring that the battery can be successfully activated and charging can begin, thereby improving product reliability and customer satisfaction; since the product's charging logic is handled by the lithium battery, this requirement needs to be addressed by the lithium battery manufacturer.

[0005] However, existing simple fast plug-in / plug-out detection circuits are insufficient to meet the requirements for rapid response to plug plug-in / plug-out actions. Therefore, this design aims to improve the existing simple fast plug-in / plug-out detection circuits so that they can respond quickly to plug plug-in / plug-out actions, while achieving the effects of simple and inexpensive circuit structure, reliable and durable performance. Utility Model Content

[0006] The purpose of this invention is to provide a fast plug-in / plug-out detection circuit, comprising: a charging activation circuit consisting of a charger voltage input terminal C+, a diode D1, a capacitor C1, resistors R3, R5, and R6, and a MOSFET Q2; wherein, the capacitance of the capacitor C1 is adjusted according to the required pulse width; during the charging process of the charger voltage input terminal C+ to the capacitor C1, the resistor R6 generates a voltage drop due to the charging current, which drives the MOSFET Q2 to conduct, causing the activation signal output terminal to output an activation signal; when the capacitor C1 is fully charged, there is no charging current and no voltage drop across the resistor R6, the MOSFET Q2 is turned off, the activation signal output terminal stops outputting the activation signal, and even when there is a continuous voltage input at the charger voltage input terminal C+, the activation signal output terminal remains in a state of no activation signal output.

[0007] Preferably, the fast plug-in / plug-out detection circuit includes: the anode of diode D1 is connected to the charger voltage input terminal C+, and the cathode of diode D1 is connected to one end of capacitor C1; the other end of capacitor C1 is connected to ground via resistors R3, R5, and R6 in series; and resistor R6 is connected to the gate and source of MOSFET Q2, the source of MOSFET Q2 is grounded, and the drain of MOSFET Q2 serves as the activation signal output terminal; wherein, diode D1 is used to cut off the external discharge path of capacitor C1 when there is no voltage input at the charger voltage input terminal C+; resistors R3, R5, and R6 together constitute the charging current limiting resistor of capacitor C1.

[0008] Diode D1 effectively blocks the external discharge path of capacitor C1 when there is no voltage at the C+ terminal, preventing charge loss and ensuring rapid charging initiation when voltage is applied to the C+ terminal again. This ensures sensitive response to intermittent signal input and is suitable for scenarios involving intermittent plug interruptions and repeated on / off cycles. Resistors R3, R5, and R6 are connected in series to limit the charging current. This prevents excessive charging current from damaging components such as capacitor C1 and MOSFET Q2, and also stabilizes the voltage drop across resistor R6, ensuring the accurate on / off state of MOSFET Q2.

[0009] Preferably, the quick plug-in / unplug detection circuit includes: when the quick plug-in / unplug function is not required, the discharge circuit is configured as a first mode discharge circuit: the first mode discharge circuit includes a resistor R2, which is connected in parallel across the capacitor C1. When there is no voltage input at the charger voltage input terminal C+, the charge of the capacitor C1 is released through the resistor R2.

[0010] This utility model can flexibly adapt to different usage needs. When the quick plug-in function is not required, the first mode discharge circuit is formed by the resistor R2 connected in parallel across the capacitor C1. When there is no voltage input at the charger voltage input terminal C+, the residual charge of capacitor C1 is smoothly released, avoiding charge retention from affecting the reliability of the next charging activation. At the same time, it simplifies the circuit logic, reduces static energy consumption, and improves the stability of circuit operation.

[0011] Preferably, the fast plug-in / plug-out detection circuit includes: when the fast plug-in / plug-out function is required, the discharge circuit is configured as a second-mode discharge circuit, the second-mode discharge circuit includes a MOSFET Q1 and a resistor R4, the resistor R2 is removed, the MOSFET Q1 is connected in series with the resistors R4 and R3 and then connected in parallel across the capacitor C1, which is used to quickly discharge the capacitor C1 when there is no voltage input at the charger voltage input terminal C+, so that the MOSFET Q2 can be turned on every time the charger voltage input terminal C+ is powered on, and transmit the activation signal to the main power supply or analog front end to activate the battery pack.

[0012] Preferably, the resistance of resistor R2 is 500kΩ to 1MΩ.

[0013] The resistor R2 is selected with a high resistance value of 500kΩ to 1MΩ. This can ensure that when there is no voltage at the charger voltage input terminal C+, the capacitor C1 can smoothly release the residual charge, avoiding the impact of charge retention on the reliability of the next charging activation. It can also minimize the static energy consumption of the circuit and reduce standby power loss.

[0014] Preferably, the fast plug-in detection circuit further includes a Zener diode Z1, which is connected in parallel between the gate and source of the MOSFET Q1.

[0015] Preferably, the fast plug-in detection circuit further includes a Zener diode Z2, which is connected in parallel between the gate and source of the MOSFET Q2.

[0016] Zener diodes Z1 and Z2 are connected in parallel between the gate and source of MOSFETs Q1 and Q2, respectively. This precisely clamps the gate-source voltage of the corresponding MOSFETs, effectively suppressing instantaneous voltage spikes during rapid insertion and removal, and preventing overvoltage breakdown of the MOSFETs. This design improves the circuit's anti-interference capability and component durability, ensuring stable and reliable discharge and activation functions under rapid insertion and removal scenarios.

[0017] This invention offers the following advantages: The rapid plug-in / plug-out detection circuit addresses the pain point of poor plug contact during charging of rechargeable lithium battery products, providing significant benefits. Through the collaborative design of capacitor C1, resistor R6, and MOSFET Q2, when power supply voltage is applied (rapid plug-in / plug-out), capacitor C1 charges, causing resistor R6 to generate sufficient voltage to trigger MOSFET Q2 to conduct, quickly outputting a WAKE_UP activation signal. This ensures the BMS promptly captures various intermittent voltage signals from the charger (such as signals generated by arcing, flashover, or repeated on / off cycles), completely solving the problem of a powered-off battery failing to activate charging due to the lack of a detected connection signal, thus avoiding the user's confusion of mistakenly believing charging is successful. For rapid plug-in / plug-out scenarios, the instantaneous voltage spike generated during plug-in / plug-out can reversely break down the Zener diode Z1, and the resulting clamping voltage triggers MOSFET Q1 to conduct. Combined with the design where the total resistance of bleeder resistors R3 and R4 is much smaller than that of bleeder resistor R2, a low-impedance rapid discharge path is constructed, allowing capacitor C1 to quickly release residual charge and rapidly return to the ready-to-activate state, ensuring reliable circuit response regardless of subsequent intermittent connections. The bleeder resistor R2 is chosen with a large resistance value to ensure smooth discharge during normal power outages and reduce the circuit's static energy consumption. The design of R4, with a resistance value much smaller than R3, balances rapid discharge efficiency with current limiting protection to prevent component damage. The entire circuit uses only basic components such as capacitors, resistors, and MOSFETs, resulting in a simple, inexpensive, reliable, and durable structure. Attached Figure Description

[0018] Figure 1 This is a fast plug-in / plug-out detection circuit in one embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the transmission path of the activation signal when capacitor C1 is charging in one embodiment of this application.

[0020] Figure 3 This is a schematic diagram of the normal charge discharge path of capacitor C1 in one embodiment of this application.

[0021] Figure 4 This is a schematic diagram of the charge transfer path of capacitor C1 when a rapid plugging and unplugging operation occurs during the power supply connection of the power supply voltage in one embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] This embodiment provides a fast plug-in / plug-out detection circuit, referencing... Figure 1 and Figure 2 The circuit includes a charging activation circuit consisting of a charger voltage input terminal C+, a diode D1, a capacitor C1, resistors R3, R5, and R6, and a MOSFET Q2. The capacitance of capacitor C1 is adjusted according to the required pulse width. During the charging process from the charger voltage input terminal C+ to capacitor C1, resistor R6 experiences a voltage drop due to the charging current. This voltage drop drives the MOSFET Q2 to conduct, causing the activation signal output terminal to output an activation signal. When capacitor C1 is fully charged, there is no charging current and no voltage drop across resistor R6, the MOSFET Q2 is turned off, and the activation signal output terminal stops outputting the activation signal. Furthermore, even with a continuous voltage input at the charger voltage input terminal C+, the activation signal output terminal remains in a state without any activation signal output.

[0024] In this embodiment, the core function of the fast plug-in / plug-out detection circuit is achieved through a charging activation circuit. This circuit consists of a charger voltage input terminal C+, a diode D1, a capacitor C1, resistors R3, R5, and R6, and a MOSFET Q2. These components work together to accurately output and turn off the charging activation signal. The capacitor C1, as a key energy storage component, can have its capacitance flexibly adjusted according to the required activation signal pulse width in practical applications, adapting to the varying signal duration requirements of different BMSs. Specifically, when the charger voltage input terminal C+ is connected to a voltage source and charges capacitor C1, the charging current flowing through resistor R6 generates a voltage drop. Once this voltage drop reaches the gate-source turn-on voltage of MOSFET Q2, MOSFET Q2 is turned on, and the activation signal is output from its drain-side activation signal output terminal. After capacitor C1 is fully charged, the charging current stops, no current flows through resistor R6, and the voltage drop returns to zero. MOSFET Q2 is turned off due to the loss of its driving voltage, and the activation signal output terminal stops outputting the signal. Even if the charger voltage input terminal C+ is continuously supplied with voltage, the activation signal output terminal remains in a state of no signal output to avoid redundant signals interfering with the normal operation logic of the BMS.

[0025] Furthermore, the fast plug-in / plug-out detection circuit includes: the anode of diode D1 is connected to the charger voltage input terminal C+, and the cathode of diode D1 is connected to one end of capacitor C1; the other end of capacitor C1 is connected to ground via resistors R3, R5, and R6 in series; and resistor R6 is connected to the gate and source of MOSFET Q2, the source of MOSFET Q2 is grounded, and the drain of MOSFET Q2 serves as the activation signal output terminal; wherein, diode D1 is used to cut off the external discharge path of capacitor C1 when there is no voltage input at the charger voltage input terminal C+; resistors R3, R5, and R6 together constitute the charging current limiting resistor of capacitor C1.

[0026] In this embodiment, the quick-plug detection circuit precisely designs the component connections and functions of the charging activation circuit. Specifically, the anode of diode D1 is directly connected to the charger voltage input terminal C+, while the cathode is electrically connected to one end of capacitor C1. Utilizing the unidirectional conduction characteristic of the diode, diode D1 can effectively cut off the external discharge path of capacitor C1 when there is no voltage input at the charger voltage input terminal C+, preventing the undue loss of charge stored in capacitor C1. The other end of capacitor C1 is connected to ground via resistors R3, R5, and R6 in series. Resistors R3, R5, and R6 together constitute the charging current-limiting resistor for capacitor C1, which limits the charging current of capacitor C1 and prevents excessive current from damaging capacitor C1 and subsequent components. Simultaneously, resistor R6 is connected to the gate and source of MOSFET Q2. The source of MOSFET Q2 is grounded, and the drain directly serves as the activation signal output terminal, providing reliable circuit support for the stable output of the activation signal.

[0027] Furthermore, the quick plug-in / plug-out detection circuit, refer to Figure 3 When the quick plug-in / unplug function is not required, the discharge circuit is configured as a first mode discharge circuit: the first mode discharge circuit includes a resistor R2, which is connected in parallel across the capacitor C1. When there is no voltage input at the charger voltage input terminal C+, the charge of the capacitor C1 is released through the resistor R2.

[0028] In this embodiment, the quick-plug detection circuit can be flexibly configured with a discharge circuit mode according to actual functional requirements. When the quick-plug function is not required, the discharge circuit switches to the first mode discharge circuit. The core configuration of this first mode discharge circuit is resistor R2, which is directly connected in parallel across capacitor C1 to form a simple passive discharge path. When there is no voltage input at the charger voltage input terminal C+, the residual charge stored in capacitor C1 can be smoothly released through resistor R2. This avoids the charge remaining for a long time from affecting the response sensitivity of the next charging activation, and eliminates the need for additional switching elements to participate in the control, simplifying the circuit structure. At the same time, the high resistance of resistor R2 is used to reduce the static power consumption of the circuit.

[0029] Furthermore, the quick plug-in / plug-out detection circuit, refer to Figure 4 When a quick plug-in / plug-out function is required, the discharge circuit is configured as a second-mode discharge circuit. The second-mode discharge circuit includes a MOSFET Q1 and a resistor R4. The resistor R2 is removed. The MOSFET Q1 is connected in series with the resistors R4 and R3 and then in parallel across the capacitor C1. This is used to quickly discharge the capacitor C1 when there is no voltage input at the charger voltage input terminal C+. This ensures that the MOSFET Q2 can be turned on every time the charger voltage input terminal C+ is powered on, and the activation signal is transmitted to the main power supply or analog front end to activate the battery pack.

[0030] Furthermore, the resistance of the resistor R2 is 500kΩ to 1MΩ.

[0031] Furthermore, the fast plug-in detection circuit also includes a Zener diode Z1, which is connected in parallel between the gate and source of the MOSFET Q1.

[0032] Furthermore, the fast plug-in detection circuit also includes a Zener diode Z2, which is connected in parallel between the gate and source of the MOSFET Q2.

[0033] In this embodiment, the fast plug-in / plug-out detection circuit features targeted optimization of the parameters and configurations of key components to ensure stable operation under different working modes. Furthermore, the resistor R2, adapted to the first mode discharge circuit, is selected from a high resistance range of 500kΩ to 1MΩ. This resistance value allows capacitor C1 to smoothly release residual charge when there is no voltage at the charger voltage input terminal C+, preventing charge retention from affecting the next activation response, while also minimizing the circuit's static power consumption, meeting the usage requirements of conventional charging scenarios. Furthermore, the circuit also includes a Zener diode Z1, connected in parallel between the gate and source of the MOSFET Q1. This effectively clamps the gate-source voltage of the MOSFET Q1, suppressing instantaneous voltage spikes generated during fast plug-in / plug-out, preventing the MOSFET Q1 from being damaged by overvoltage, and ensuring the reliable operation of the second mode discharge circuit. Furthermore, a Zener diode Z2 is added to the circuit and connected in parallel between the gate and source of the MOSFET Q2. By precisely clamping the voltage, the MOSFET Q2 is prevented from falsely turning on or off due to input voltage fluctuations, thus ensuring the accuracy and stability of the activation signal output.

[0034] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0036] Although the description of this application has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A quick plug detection circuit, characterized by, include: The charging activation circuit consists of the charger voltage input terminal C+, diode D1, capacitor C1, resistor R3, resistor R5, resistor R6, and MOSFET Q2; wherein, the capacitance of capacitor C1 is adjusted according to the required pulse width. During the charging process from the charger voltage input terminal C+ to the capacitor C1, the resistor R6 generates a voltage drop due to the charging current. This voltage drop drives the MOSFET Q2 to turn on, causing the activation signal to be output from the activation signal output terminal. When capacitor C1 is fully charged, there is no charging current and no voltage drop across resistor R6, MOSFET Q2 is turned off, the activation signal output terminal stops outputting the activation signal, and even when there is a continuous voltage input at the charger voltage input terminal C+, the activation signal output terminal still remains in a state of no activation signal output.

2. The plug and play detection circuit of claim 1, wherein, include: The anode of diode D1 is connected to the charger voltage input terminal C+, and the cathode of diode D1 is connected to one end of capacitor C1; the other end of capacitor C1 is connected to ground in series with resistors R3, R5, and R6. Furthermore, the resistor R6 is connected to the gate and source of the MOSFET Q2, the source of the MOSFET Q2 is grounded, and the drain of the MOSFET Q2 serves as the activation signal output terminal. Diode D1 is used to cut off the external discharge path of capacitor C1 when there is no voltage input at the charger voltage input terminal C+; resistors R3, R5, and R6 together constitute the charging current limiting resistor of capacitor C1.

3. The plug-and-play detection circuit of claim 2, wherein, include: When the quick plug-in / unplug function is not required, the discharge circuit is configured as a first mode discharge circuit: the first mode discharge circuit includes a resistor R2, which is connected in parallel across the capacitor C1. When there is no voltage input at the charger voltage input terminal C+, the charge of the capacitor C1 is released through the resistor R2.

4. The plug and play detection circuit of claim 3, wherein, include: When a quick plug-in / plug-out function is required, the discharge circuit is configured as a second-mode discharge circuit. The second-mode discharge circuit includes a MOSFET Q1 and a resistor R4. The resistor R2 is removed. The MOSFET Q1 is connected in series with the resistors R4 and R3 and then connected in parallel across the capacitor C1. This is used to quickly discharge the capacitor C1 when there is no voltage input at the charger voltage input terminal C+. This ensures that the MOSFET Q2 can be turned on every time the charger voltage input terminal C+ is powered on, and the activation signal is transmitted to the main power supply or analog front end to activate the battery pack.

5. The plug-and-play detection circuit of claim 4, wherein, include: The resistance of resistor R2 is 500kΩ to 1MΩ.

6. The plug-and-play detection circuit of claim 5, wherein, Also includes: Zener diode Z1, The Zener diode Z1 is connected in parallel between the gate and source of the MOSFET Q1.

7. The plug-and-play detection circuit of claim 6, wherein, Also includes: Zener diode Z2, The Zener diode Z2 is connected in parallel between the gate and source of the MOSFET Q2.

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