Load detection circuit in lithium battery high-side protection system

Abstract

The utility model discloses a load detection circuit in a lithium battery high-side protection system, which belongs to the technical field of lithium battery protection and comprises a first metal oxide semiconductor (MOS) tube M1, a first triode Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a first diode D1. According to the invention, under the condition that the lithium battery analog front-end chip does not provide the load detection function, the load detection function is realized through an external circuit.

Description

Technical Field

[0001] This circuit is used in a lithium battery high-side protection system. By using an external circuit, it achieves the load detection function with fewer components. At the same time, it isolates the high voltage of the battery pack from the MCU power supply, thereby making the lithium battery protection system more complete and suitable for application scenarios with high requirements for lithium battery safety performance. Background Technology

[0002] Currently, traditional lithium battery analog front-end protection chips suffer from inconsistent functionality. Most commercially available lithium battery analog front-end protection chips lack load detection capabilities, resulting in the system's inability to monitor the load connection status in real time. This can lead to safety hazards when the battery is over-discharged or short-circuited, failing to meet the requirements of demanding application scenarios. This invention provides a load detection circuit that does not rely on analog front-end protection chips, enabling real-time monitoring of load connection. Summary of the Invention

[0003] A load detection circuit in a lithium battery high-side protection system is characterized by comprising a first MOSFET M1, a first transistor Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a first diode D1. The source of the first MOSFET M1 is connected to its gate via the third resistor R3 and simultaneously connected to B+ and the cathode of the first diode D1. The gate of the first MOSFET M1 is connected to P+ via the fourth resistor R4 and simultaneously connected to the anode of the first diode D1. The drain of the first MOSFET M1 is grounded via the first resistor R1 and the second resistor R2. The base of the first transistor Q1 is grounded via the second resistor R2. The collector of the first transistor Q1 is connected to MCU_VCC. The emitter of the first transistor Q1 is grounded via the fifth resistor R5 and simultaneously connected to MCU_IO via the sixth resistor R6. Attached Figure Description

[0004] Figure 1 This is a circuit diagram of the load detection circuit in the lithium battery high-side protection system of the present invention. Detailed Implementation

[0005] A load detection circuit in a lithium battery high-side protection system is characterized by comprising a first MOSFET M1, a first transistor Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a first diode D1. The source of the first MOSFET M1 is connected to its gate via the third resistor R3 and simultaneously connected to B+ and the cathode of the first diode D1. The gate of the first MOSFET M1 is connected to P+ via the fourth resistor R4 and simultaneously connected to the anode of the first diode D1. The drain of the first MOSFET M1 is grounded via the first resistor R1 and the second resistor R2. The base of the first transistor Q1 is grounded via the second resistor R2. The collector of the first transistor Q1 is connected to MCU_VCC. The emitter of the first transistor Q1 is grounded via the fifth resistor R5 and simultaneously connected to MCU_IO via the sixth resistor R6.

[0006] In this embodiment, the resistance values ​​and accuracies of each resistor are set as follows: the resistance of the first resistor R1 is 10MΩ±5%, the resistance of the second resistor R2 is 1MΩ±5%, the resistance of the third resistor R3 is 1MΩ±5%, the resistance of the fourth resistor R4 is 10MΩ±5%, the resistance of the fifth resistor R5 is 100KΩ±5%, and the resistance of the sixth resistor R6 is 1KΩ±5%. In the circuit, B+ is the total positive terminal of the battery pack, P+ is the positive terminal of the load, MCU_VCC is the power supply of the MCU, and MCU_IO is the general purpose input / output pin of the MCU.

[0007] This circuit uses the voltage at the P+ terminal to make logical judgments. When the load is not connected or the high-side discharge FET is turned on, the voltage at P+ is floating and at the B+ level, and the MOSFET M1 is not turned on. At this time, MCU_IO remains at a low level. When the load is connected and the high-side discharge FET is not turned on, the P+ voltage is pulled to ground, the MOSFET M1 turns on, and further turns on the transistor Q1. At this time, MCU_IO remains at a high level. The specific business logic for waking up the MCU and detecting the load connection is realized by configuring an interrupt in the MCU.

[0008] It will be apparent to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0009] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This description is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other ways that can be understood by those skilled in the art.

Claims

1. A load detection circuit in a lithium battery high-side protection system, characterized by: The circuit includes a first MOSFET M1, a first transistor Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a first diode D1. The source of the first MOSFET M1 is connected to its own gate through the third resistor R3, and is also connected to B+ and the cathode of the first diode D1. The gate of the first MOSFET M1 is connected to P+ through the fourth resistor R4, and is also connected to the anode of the first diode D1. The drain of the first MOSFET M1 is grounded through the first resistor R1 and the second resistor R2. The base of the first transistor Q1 is grounded through the second resistor R2. The collector of the first transistor Q1 is connected to MCU_VCC. The emitter of the first transistor Q1 is grounded through the fifth resistor R5 and is also connected to MCU_IO through the sixth resistor R6.

2. The load detection circuit in a lithium battery high-side protection system of claim 1, wherein: The resistance of the first resistor R1 is 10MΩ±5%, the resistance of the second resistor R2 is 1MΩ±5%, the resistance of the third resistor R3 is 1MΩ±5%, the resistance of the fourth resistor R4 is 10MΩ±5%, the resistance of the fifth resistor R5 is 100KΩ±5%, and the resistance of the sixth resistor R6 is 1KΩ±5%. In the circuit, B+ is the positive terminal of the battery pack, P+ is the positive terminal of the load, MCU_VCC is the power supply of the MCU, and MCU_IO is the general-purpose input / output pin of the MCU.

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