Battery protection board pulse discharge soft start circuit

Abstract

This utility model relates to the field of battery startup circuit technology, specifically a pulse discharge soft-start circuit for a battery protection board. It includes a discharge field-effect transistor (MOSFET), a charging field-effect transistor (MOSFET), a front-end chip (AFE), and a controller (MCU). When the discharge field-effect transistor (MOSFET) is turned on, the front-end chip (AFE) detects an excessive instantaneous current during the pulse width Tw time and stops outputting the discharge field-effect transistor (MOSFET) drive signal. After pausing the pulse interval Tint time, the controller (MCU) starts outputting the discharge field-effect transistor (MOSFET) drive signal, turning on the MOSFET. If the instantaneous current is still excessive, the above steps are repeated until the instantaneous current drops to the design value, completing the battery soft start. By controlling the on / off state of the discharge field-effect transistor (MOSFET) through the controller (MCU), pulse pre-discharge is performed on the load to prevent excessive instantaneous current during battery startup, which could cause the protection board to fail to start or be damaged, thus ensuring normal battery startup.

Description

Technical Field

[0001] This utility model relates to the field of battery starting circuit technology, and in particular to a pulse discharge soft start circuit for battery protection boards. Background Technology

[0002] When a capacitive load is initially connected to the battery circuit, it is essentially in a short-circuit state (from a current perspective), generating a large charging current. For example, a large electrolytic capacitor may initially draw several amperes or even higher during charging. When the battery discharges through the battery management system (BMS) to the capacitive load, the voltage across the load is zero the instant it is connected to the circuit. According to the capacitor charging formula... (i is the charging current, C is the capacitance value, (This refers to the rate of voltage change). At this point, a large voltage difference exists between the battery and the load, resulting in a large rate of voltage change. The capacitor needs to quickly establish an electric field to store charge, drawing a large amount of charge from the battery, leading to a very large instantaneous current. This is equivalent to the battery rapidly charging the capacitor. The battery itself has a certain electromotive force (EMF), and when a capacitive load is connected, this EMF is applied across the capacitive load. Since the initial voltage of the capacitive load is 0, the large voltage difference causes a large amount of charge to move rapidly, forming a large instantaneous current. Just as water flows faster when there is a large difference in water level, charges move faster when there is a large voltage difference, thus generating a large instantaneous current. This large instantaneous current can easily cause the protection board to fail to activate or be damaged. To ensure normal battery discharge, excessive current must be avoided. Summary of the Invention

[0003] The main purpose of this invention is to provide a pulse discharge soft-start circuit for battery protection boards, in order to solve the problem in related technologies that instantaneous high current can easily cause the protection board to fail to start or be damaged.

[0004] To achieve the above objectives, according to one aspect of the present invention, a pulse discharge soft-start circuit for a battery protection board is provided, including a battery pack (PACK) and a load. The battery pack (PACK) includes a discharge field-effect transistor (MOSFET), a charging field-effect transistor (MOSFET), a front-end chip (AFE), and a controller (MCU). When the discharge field-effect transistor (MOSFET) is turned on, the front-end chip (AFE) detects an excessive instantaneous current during the pulse width Tw time, stops outputting the discharge field-effect transistor (MOSFET) drive signal, and pauses the pulse interval time Tint time. After this pause, the controller (MCU) starts outputting the discharge field-effect transistor (MOSFET) drive signal, and the discharge field-effect transistor (MOSFET) is turned on. If the instantaneous current is still too large, the above steps are repeated until the instantaneous current drops to the design value, thus completing the battery soft start.

[0005] Furthermore, the battery pack also includes a battery, the positive terminal B+ of which is connected to the drain of the discharge field-effect transistor MOS, and the negative terminal B- of which is connected to the negative terminal P- of the load. The battery supplies power to the startup circuit.

[0006] Furthermore, the front-end chip AFE is connected to the gate of the discharge field-effect transistor MOS. The front-end chip AFE is responsible for acquiring analog signals from the battery, including voltage, current, and temperature, and converting the analog signals into digital signals while monitoring the battery status.

[0007] Furthermore, the front-end chip AFE and the controller MCU are bidirectionally connected via an SPI interface. The front-end chip AFE converts the acquired analog signals into digital signals and transmits them to the controller MCU. The controller MCU analyzes and processes the digital signals and sends control commands to the front-end chip AFE and the discharge field-effect transistor MOS.

[0008] Furthermore, the source of the charging field-effect transistor MOS is connected to the source of the discharging field-effect transistor MOS, and the drain of the charging field-effect transistor MOS is connected to the positive terminal P+ of the load. During discharge, the controller MCU controls the discharging field-effect transistor MOS to conduct, and the battery energy flows to the load through the discharging field-effect transistor MOS and the charging field-effect transistor MOS. During charging, the controller MCU controls the charging field-effect transistor MOS to conduct, and the charging power supply provides charging current to the positive terminal B+ of the battery through the drain of the charging field-effect transistor MOS.

[0009] Furthermore, the pulse width Tw is 10µs to 500µs.

[0010] Furthermore, the pulse interval time Tint is 10ms to 500ms.

[0011] Compared with the prior art, the present invention has the following advantages: by controlling the on and off states of the discharge field-effect transistor MOS through the controller MCU, the load is pulsed pre-discharged to prevent the protection board from failing to start or being damaged due to excessive instantaneous current when the battery starts, thus ensuring the normal start-up of the battery. Attached Figure Description

[0012] Figure 1 This is a block diagram of the battery soft-start principle circuit of this utility model. Detailed Implementation

[0013] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0014] This embodiment provides a pulse discharge soft-start circuit for a battery protection board, such as... Figure 1 As shown, the system includes a battery pack and a load. The battery pack includes a discharge field-effect transistor (MOSFET), a charging field-effect transistor (MOSFET), a front-end chip (AFE), and a controller (MCU). When the discharge field-effect transistor (MOSFET) is turned on, the front-end chip (AFE) detects an excessive instantaneous current during the pulse width Tw time and stops outputting the discharge field-effect transistor (MOSFET) drive signal. After pausing the pulse interval Tint time, the controller (MCU) starts outputting the discharge field-effect transistor (MOSFET) drive signal, and the discharge field-effect transistor (MOSFET) is turned on. If the instantaneous current is still too large, the above steps are repeated until the instantaneous current drops to the design value, completing the battery soft start.

[0015] The battery pack also includes a battery. The positive terminal (B+) of the battery is connected to the drain of a discharge field-effect transistor (MOSFET), and the negative terminal (B-) of the battery is connected to the negative terminal (P-) of the load. The battery supplies power to the startup circuit. The MOSFET, as a voltage-controlled device, operates in the battery discharge circuit. The current output from the positive terminal (B+) of the battery flows into the drain of the MOSFET. When a suitable voltage signal is applied to the gate of the MOSFET to turn it on, the current flows from the drain to the source, thus supplying power to the load.

[0016] The front-end chip (AFE) is connected to the gate of the discharge field-effect transistor (MOSFET). The AFE is responsible for acquiring analog signals from the battery, including voltage, current, and temperature, and converting them into digital signals while monitoring the battery status. When the AFE detects a need for discharge control (such as overcurrent or over-discharge protection), it transmits the signal to the controller MCU. After processing by the MCU, the voltage at the gate of the MOSFET is controlled to turn the MOSFET on or off, thereby managing the battery's discharge process.

[0017] The front-end chip (AFE) and the controller MCU are bidirectionally connected via the SPI interface. The AFE converts the acquired analog signals into digital signals and transmits them to the controller MCU. The controller MCU analyzes and processes the digital signals and sends control commands to the AFE and the discharge field-effect transistor (MOS).

[0018] The source of the charging MOSFET is connected to the source of the discharging MOSFET, and the drain of the charging MOSFET is connected to the positive terminal P+ of the load. During discharge, the controller MCU turns on the discharging MOSFET, and battery energy flows to the load through the discharging MOSFET and the charging MOSFET. During charging, the controller MCU turns on the charging MOSFET, and the charging power supply provides charging current to the positive terminal B+ of the battery through the drain of the charging MOSFET. When the charging MOSFET is turned on, external current flows in from the drain of the charging MOSFET, through its internal channel to its source, and thus charges the battery.

[0019] The pulse width Tw is 10µs ~ 500µs.

[0020] The pulse interval time Tint is 10ms ~ 500ms.

[0021] When the circuit is unloaded, lightly loaded, or heavily loaded, the instantaneous starting current is small, and there is no need to pre-discharge the load. The battery protection board directly turns on the discharge tube to start discharging the load.

[0022] When the load is a large capacitive load and the motor is soft-started, the instantaneous starting current is very large, requiring pulse pre-discharge of the load. The working process is as follows:

[0023] S1: The discharge field-effect transistor MOS is turned on. The front-end chip AFE of the battery protection board detects excessive current at time Tw and stops outputting the discharge field-effect transistor MOS drive signal.

[0024] S2: Following a Tint interval, the MCU controller begins outputting the discharge field-effect transistor (MOS) drive signal;

[0025] S3: If the instantaneous starting current is still too high, return to S1 or continue to S4;

[0026] S4: Keep the discharge field-effect transistor MOS in the on state, the battery soft start is successful, and the battery discharges normally.

[0027] During a short circuit, the instantaneous starting current is too large, requiring pulse pre-discharge of the load. The working process is as follows:

[0028] S1: The discharge field-effect transistor MOS is turned on. The front-end chip AFE of the battery protection board detects excessive current at time Tw and stops outputting the discharge field-effect transistor MOS drive signal.

[0029] S2: Following a Tint interval, the MCU controller begins outputting the discharge field-effect transistor (MOS) drive signal;

[0030] S3: Execute S1 and S2 again, and repeat this process n times (n>Nmax);

[0031] S4: Keep the discharge field-effect transistor MOS in the off state. The battery protection board judges it as a short circuit and prohibits the battery from discharging.

[0032] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A battery protection board pulse discharge soft-start circuit, including a battery pack and a load, characterized in that, The battery pack includes a discharge field-effect transistor (MOSFET), a charging field-effect transistor (MOSFET), an AFE (Automatic Front-End Chip), and a controller MCU. When the discharge field-effect transistor (MOSFET) is turned on, the AFE detects an excessive instantaneous current during the pulse width Tw time, stops outputting the discharge field-effect transistor (MOSFET) drive signal, and pauses the pulse interval Tint time. After this pause, the MCU starts outputting the discharge field-effect transistor (MOSFET) drive signal, and the MOSFET turns on. If the instantaneous current is still too large, the above steps are repeated until the instantaneous current drops to the design value, completing the battery soft start.

2. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The battery pack also includes a battery, the positive terminal B+ of which is connected to the drain of the discharge field-effect transistor MOS, and the negative terminal B- of which is connected to the negative terminal P- of the load. The battery supplies power to the startup circuit.

3. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The front-end chip AFE is connected to the gate of the discharge field-effect transistor MOS. The front-end chip AFE is responsible for acquiring analog signals from the battery, including voltage, current, and temperature, and converting the analog signals into digital signals while monitoring the battery status.

4. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The front-end chip (AFE) and the controller MCU are bidirectionally connected via an SPI interface. The front-end chip (AFE) converts the acquired analog signals into digital signals and transmits them to the controller MCU. The controller MCU analyzes and processes the digital signals and sends control commands to the front-end chip (AFE) and the discharge field-effect transistor (MOS).

5. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The source of the charging field-effect transistor MOS is connected to the source of the discharging field-effect transistor MOS, and the drain of the charging field-effect transistor MOS is connected to the positive terminal P+ of the load. During discharge, the controller MCU controls the discharging field-effect transistor MOS to turn on, and the battery energy flows to the load through the discharging field-effect transistor MOS and the charging field-effect transistor MOS. During charging, the controller MCU controls the charging field-effect transistor MOS to turn on, and the charging power supply provides charging current to the positive terminal B+ of the battery through the drain of the charging field-effect transistor MOS.

6. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The pulse width Tw is 10µs to 500µs.

7. The battery protection board pulse discharge soft-start circuit according to claim 1, characterized in that, The pulse interval time Tint is 10ms to 500ms.

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