High-side discharge MOS protection circuit under charging reverse connection condition

Abstract

The utility model discloses a high-side discharge MOS (Metal Oxide Semiconductor) protection circuit under a charging reverse connection condition, which belongs to the technical field of battery management systems (BMS) and comprises a first MOS tube Q1, a first resistor R1, a second resistor R2, a third resistor R3, a first switching diode D1 and a first voltage stabilizing diode Z1. According to the circuit, the discharge loop closing module is additionally arranged, so that the discharge loop can be automatically detected and closed under the abnormal condition of reverse connection of the charger, and key devices (such as MOS (Metal Oxide Semiconductor) tubes) in the circuit are protected from being damaged due to over-current impact.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery management system (BMS), and particularly relates to a high-side discharge driving circuit in a battery management system. In the battery management system, the high-side discharge MOS transistor is used to control the discharge process of the battery, ensuring that the battery can work safely and efficiently during discharge. However, in the case of reverse connection of the charger, the traditional discharge driving circuit may face the problem of reverse current flowing into the battery system, causing the discharge MOS transistor to bear abnormal voltage or current, and further causing device burnout or performance degradation. Therefore, the present application provides a high-side discharge MOS protection circuit under the condition of reverse connection of the charger, aiming to solve the problem of protection of the discharge MOS transistor under the condition of reverse connection of the charger. BACKGROUND

[0002] In the existing battery management system, the design of the high-side discharge driving circuit usually relies on the switching characteristics of the MOS transistor to control the discharge process of the battery. However, when the charger is reversely connected, the current may flow reversely into the battery system, causing the discharge MOS transistor to bear reverse voltage or current. This abnormal working condition may cause problems such as overcurrent impact, voltage stress, thermal runaway, etc. In order to solve these problems, the existing technical solutions usually use the following methods: using reverse diode protection, increasing overcurrent protection circuit or voltage clamping circuit, etc. However, these methods cannot cope with the problem of reverse current flow. Although the existing technology provides protection to some extent, there is still a risk of damage to the discharge MOS transistor under the condition of reverse connection of the charger. Therefore, a circuit design is needed that can quickly respond and protect the discharge MOS transistor under the condition of reverse connection of the charger. SUMMARY

[0003] This invention provides a high-side discharge MOS protection circuit under reverse charging conditions. By adding a discharge MOS protection circuit module to the traditional high-side discharge drive circuit, it effectively solves the overcurrent surge and voltage stress problems faced by the discharge MOS transistor when the charger is reverse connected. This invention includes a first MOS transistor Q1, a first resistor R1, a second resistor R2, a third resistor R3, a first switching diode D1, and a first Zener diode Z1. The drain of the first MOS transistor Q1 is connected to the high-side discharge output signal DSG through the first resistor R1. The source of the first MOS transistor Q1 is connected to the anode of the first Zener diode Z1, one end of the second resistor R2, and the positive input terminal PACK+ of the charger. The gate of the first MOS transistor Q1 is connected to the cathode of the first Zener diode Z1, the other end of the second resistor R2, and the cathode of the first switching diode D1 through the third resistor R3. The anode of the first switching diode D1 is connected to the negative input terminal PACK- of the charger. Through the above technical solution, this invention not only provides effective protection under reverse charging conditions but also responds quickly to other abnormal operating conditions (such as short circuits and sudden load changes), ensuring the safety and reliability of the battery management system. Attached Figure Description

[0004] Figure 1 This is a circuit diagram of the high-side discharge MOS protection circuit under reverse charging conditions in this invention. Detailed Implementation

[0005] The invention will be further illustrated below through non-limiting embodiments to help you understand it.

[0006] This invention relates to a high-side discharge MOS protection circuit under reverse charging conditions, such as... Figure 1 It includes a first MOSFET Q1, a first resistor R1, a second resistor R2, a third resistor R3, a first switching diode D1, and a first Zener diode Z1. The drain of the first MOSFET Q1 is connected to the high-side discharge output signal DSG through the first resistor R1. The source of the first MOSFET Q1 is connected to the anode of the first Zener diode Z1, one end of the second resistor R2, and the positive input terminal PACK+ of the charger. The gate of the first MOSFET Q1 is connected to the cathode of the first Zener diode Z1, the other end of the second resistor R2, and the cathode of the first switching diode D1 through the third resistor R3. The anode of the first switching diode D1 is connected to the negative input terminal PACK- of the charger.

[0007] When the charger is reverse-connected, this circuit will cause a negative voltage to appear at the positive terminal PACK+ of the charger. At this time, the gate voltage of Q1 is greater than the source voltage, the first MOSFET Q1 is turned on, and the high-side discharge output signal DSG is pulled down to the voltage of the positive terminal PACK+ of the charger, thus protecting the discharge MOSFET.

[0008] In abnormal conditions (such as short circuit, load mutation or power reverse connection), the discharge circuit is quickly cut off to avoid current continuous over-limit, and to protect MOS tube and other key devices from burnout or performance degradation caused by over-current impact.

[0009] The application solves the protection problem of the traditional high-side discharge drive circuit under the reverse connection of the charger through the innovative circuit design, has the advantages of fast response speed and remarkable protection effect, and the like. The application is not only suitable for the battery management system, but also can be widely applied to other electronic devices requiring high-side discharge protection, and has broad market prospect and application value.

Claims

1. A high-side discharge MOS protection circuit in a reverse connection charging situation, comprising a first MOS tube Q1, a first resistor R1, a second resistor R2, a third resistor R3, a first switching diode D1, and a first voltage stabilizing diode Z1, wherein the drain of the first MOS tube Q1 is connected to a high-side discharge output signal DSG through the first resistor R1, the source of the first MOS tube Q1 is connected to the anode of the first voltage stabilizing diode Z1, one end of the second resistor R2, and a charger input positive pole PACK+, the gate of the first MOS tube Q1 is connected to the cathode of the first voltage stabilizing diode Z1, the other end of the second resistor R2, and the cathode of the first switching diode D1 through the third resistor R3, and the anode of the first switching diode D1 is connected to a charger input negative pole PACK-.

2. The high-side discharge MOS protection circuit under charge reverse connection according to claim 1, characterized in that: In the circuit, DSG is a high-side discharge output signal from an AFE, PACK+ is a charger input positive pole, and PACK- is a charger input negative pole.

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