A lithium battery pre-discharge circuit

Abstract

The utility model discloses a lithium battery pre -discharge circuit, including pre -discharge resistance, MCU and pre -discharge control circuit, pre -discharge resistance is connected in series between lithium battery and host capacitor, and pre -discharge control circuit includes MOS pipe Q1, Q2 that connects in series at pre -discharge resistance both ends respectively, the MCU connects the host capacitor end voltage of gathering, and the on -off of MOS pipe Q1, Q2 is controlled. The utility model designs a lithium battery pre -discharge circuit, by setting up pre -discharge resistance in lithium battery discharge circuit, limit host capacitor charging initial stage's current, make capacitor voltage slowly rise to avoid generating excessive current impact, protect component damage, prolong host service life. When capacitor voltage satisfies the opening condition, and pre -discharge process is completed, and main circuit is closed, and system enters normal working condition.

Description

Technical Field

[0001] This utility model relates to lithium battery technology, and in particular to a lithium battery pre-discharge circuit. Background Technology

[0002] When lithium batteries supply power to a load, excessive current surges can easily occur during the discharge circuit startup, damaging load components and affecting the lifespan of the main unit.

[0003] It is necessary to design a pre-discharge circuit. By incorporating a pre-discharge unit into the lithium battery discharge circuit, the current during the initial charging of the main capacitor is limited, allowing the capacitor voltage to rise slowly. This avoids excessive current surges, protects components from damage, and extends the lifespan of the main unit. When the capacitor voltage meets the activation conditions, the pre-discharge process is complete, the main circuit closes, and the system enters normal operation. Utility Model Content

[0004] The purpose of this invention is to provide a lithium battery pre-discharge circuit that makes lithium battery discharge safer.

[0005] The technical solution of this utility model is:

[0006] A lithium battery pre-discharge circuit includes a pre-discharge resistor, an MCU, and a pre-discharge control circuit. The pre-discharge resistor is connected in series between the lithium battery and the host capacitor. The pre-discharge control circuit includes MOSFETs Q1 and Q2 connected in series across the pre-discharge resistor. The MCU is connected to acquire the voltage at the end of the host capacitor and controls the switching on and off of the MOSFETs Q1 and Q2.

[0007] Preferably, the pre-discharge resistor comprises several parallel resistors.

[0008] Preferably, the MCU controls the switching on and off of MOS transistors Q1 and Q2 through two driving circuits respectively.

[0009] Preferably, the two drive circuits have the same structure. The first drive circuit includes a MOSFET Q8, resistors R4, R7, R11, R15, and a Zener diode D1. The source of the MOSFET Q1 is connected to the host capacitor, the drain is connected to a pre-discharge resistor, and the gate is connected to the drain of the MOSFET Q8 through resistor R7. The gate of the MOSFET Q1 is also connected to its own source through a parallel resistor R4 and Zener diode D1. The source of the MOSFET Q8 is grounded, and its gate is connected to a control terminal CHG_YCCtrl of the MCU through resistor R11. The gate is also connected to its own drain through resistor R15.

[0010] Preferably, a main discharge circuit is also connected between the lithium battery and the host capacitor. The main discharge circuit is also connected to and controlled by an MCU. After the MCU detects that the host capacitor meets the host power supply voltage, it controls the pre-discharge circuit to open and the main discharge circuit to close to supply power to the load.

[0011] The advantages of this utility model are:

[0012] This invention designs a lithium battery pre-discharge circuit. By setting a pre-discharge resistor in the lithium battery discharge circuit, the current in the initial stage of charging of the host capacitor is limited, allowing the capacitor voltage to rise slowly. This avoids excessive current surges, protects components from damage, and extends the service life of the host. When the capacitor voltage meets the opening conditions, the pre-discharge process is completed, the main circuit is closed, and the system enters normal operating mode. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0014] Figure 1 This is a schematic diagram of the lithium battery pre-discharge circuit of this utility model.

[0015] Figure 2 This is a schematic diagram of the main discharge circuit of the lithium battery according to this utility model. Detailed Implementation

[0016] like Figure 1 As shown, this utility model proposes a lithium battery pre-discharge circuit, including a pre-discharge resistor, an MCU, and a pre-discharge control circuit. The pre-discharge resistor is connected in series between the lithium battery S+ and the host capacitor P+, and includes parallel resistors R1, R2, R3, and R5. The pre-discharge control circuit includes MOSFETs Q1 and Q2 connected in series across the pre-discharge resistor, and two drive circuits to control the on / off state of MOSFETs Q1 and Q2 respectively. The MCU is connected to collect the voltage at the host capacitor terminal and controls the on / off state of MOSFETs Q1 and Q2.

[0017] The two drive circuits have the same structure. The first drive circuit includes a MOSFET Q8, resistors R4, R7, R11, R15, and a Zener diode D1. The source of the MOSFET Q1 is connected to the host capacitor, the drain is connected to the pre-discharge resistor, and the gate is connected to the drain of the MOSFET Q8 through resistor R7. The gate of the MOSFET Q1 is also connected to its own source through the parallel resistor R4 and the Zener diode D1. The source of the MOSFET Q8 is grounded, and the gate is connected to a control terminal CHG_YCCtrl of the MCU through resistor R11. The gate is also connected to its own drain through resistor R15.

[0018] like Figure 2As shown, a main discharge circuit is also connected between the lithium battery and the host capacitor. The main discharge circuit is also connected to and controlled by the MCU. After the MCU detects that the host capacitor meets the host power supply voltage, it controls the pre-discharge circuit to open and the main discharge circuit to close to supply power to the load.

[0019] This invention limits the initial charging current of the main capacitor by setting a pre-discharge resistor in the lithium battery discharge circuit, allowing the capacitor voltage to rise slowly. This avoids excessive current surges, protects components from damage, and extends the lifespan of the main unit. When the capacitor voltage meets the activation conditions, the pre-discharge process is complete, the main circuit closes, and the system enters normal operation.

[0020] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All modifications made in accordance with the spirit and essence of the main technical solution of this utility model should be included within the scope of protection of this utility model.

Claims

1. A lithium battery pre-discharge circuit, characterized in that, The device includes a pre-discharge resistor, an MCU, and a pre-discharge control circuit. The pre-discharge resistor is connected in series between the lithium battery and the host capacitor. The pre-discharge control circuit includes MOSFETs Q1 and Q2 connected in series across the pre-discharge resistor. The MCU is connected to collect the voltage at the end of the host capacitor and controls the switching on and off of the MOSFETs Q1 and Q2. The MCU controls the on / off state of MOS transistors Q1 and Q2 through two driving circuits respectively; The two drive circuits have the same structure. The first drive circuit includes a MOSFET Q8, resistors R4, R7, R11, R15, and a Zener diode D1. The source of the MOSFET Q1 is connected to the host capacitor, the drain is connected to the pre-discharge resistor, and the gate is connected to the drain of the MOSFET Q8 through resistor R7. The gate of the MOSFET Q1 is also connected to its own source through the parallel resistor R4 and the Zener diode D1. The source of the MOSFET Q8 is grounded, and the gate is connected to a control terminal CHG_YCCtrl of the MCU through resistor R11. The gate is also connected to its own drain through resistor R15.

2. The lithium battery pre-discharge circuit according to claim 1, characterized in that, The pre-discharge resistor includes several parallel resistors.

3. The lithium battery pre-discharge circuit according to claim 2, characterized in that, The lithium battery is connected to the host capacitor via a main discharge circuit, which is also controlled by an MCU. When the MCU detects that the host capacitor meets the host power supply voltage, it controls the pre-discharge circuit to open and the main discharge circuit to close to supply power to the load.

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