Charger detection circuit in lithium battery high-side protection system

Abstract

The utility model discloses a charger detection circuit in a lithium battery high-side protection system, which belongs to the technical field of lithium battery protection and comprises a first triode Q1, a second triode Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6. According to the invention, under the condition that the lithium battery analog front-end chip does not provide the charger detection function, the charger detection function is realized through an external circuit.

Description

Technical Field

[0001] This invention relates to and specifically provides a charger detection circuit in a lithium battery high-side protection system. By using an external circuit, the charger detection function is achieved with fewer components. At the same time, the high voltage of the battery pack and the MCU power supply are isolated, 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 mainstream lithium battery protection chips do not integrate charger detection functionality, making it impossible for the system to distinguish between charger connection and load connection status. This may lead to overcharging or reverse charger connection risks, making it unsuitable for demanding application scenarios. This invention provides a charger detection circuit that does not rely on analog front-end protection chips, enabling real-time monitoring of charger connection. Summary of the Invention

[0003] A charger detection circuit in a lithium battery high-side protection system is characterized by comprising a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The base of the first transistor Q1 is connected to B+ via the first resistor R1 and to its emitter via the second resistor R2. The emitter of the first transistor Q1 is connected to P+. The collector of the first transistor Q1 is connected to ground via the third resistor R3 and the fourth resistor R4. The base of the second transistor Q2 is connected to ground via the fourth resistor R4. The emitter of the second transistor Q2 is connected to ground via the fifth resistor R5 and simultaneously connected to MCU_IO via the sixth resistor R6. The collector of the second transistor Q2 is connected to MCU_VCC. Attached Figure Description

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

[0005] A charger detection circuit in a lithium battery high-side protection system is characterized by comprising a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The base of the first transistor Q1 is connected to B+ via the first resistor R1 and to its emitter via the second resistor R2. The emitter of the first transistor Q1 is connected to P+. The collector of the first transistor Q1 is connected to ground via the third resistor R3 and the fourth resistor R4. The base of the second transistor Q2 is connected to ground via the fourth resistor R4. The emitter of the second transistor Q2 is connected to ground via the fifth resistor R5 and simultaneously connected to MCU_IO via the sixth resistor R6. The collector of the second transistor Q2 is connected to MCU_VCC.

[0006] In this embodiment, the resistance values ​​and accuracies of each resistor are set as follows: the first resistor R1 has a resistance of 1MΩ±5%, the second resistor R2 has a resistance of 100kΩ±5%, the third resistor R3 has a resistance of 10MΩ±5%, the fourth resistor R4 has a resistance of 1MΩ±5%, the fifth resistor R5 has a resistance of 100kΩ±5%, and the sixth resistor R6 has a resistance of 1kΩ±5%. In the circuit, B+ is the total positive terminal of the battery pack, P+ is the positive terminal of the charger, MCU_VCC is the power supply for 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 charger is not connected or the high-side charging FET of the lithium battery analog front-end protection chip is turned on, the voltage at P+ is floating and at the B+ level, and transistor Q1 is not turned on. At this time, MCU_IO remains at a low level. When the charger is connected and the high-side charging FET of the lithium battery analog front-end protection chip is not turned on, the voltage at P+ rises to the positive voltage of the charger, transistor Q1 turns on, and further turns on transistor Q2. At this time, MCU_IO remains at a high level. The specific business logic for waking up the MCU and detecting the charger 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 charger detection circuit in a lithium battery high-side protection system, characterized by: The circuit comprises a first transistor Q1, a second transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The base of the first transistor Q1 is connected to B+ through the first resistor R1 and to its own emitter through the second resistor R2. The emitter of the first transistor Q1 is connected to P+. The collector of the first transistor Q1 is connected to ground through the third resistor R3 and the fourth resistor R4. The base of the second transistor Q2 is connected to ground through the fourth resistor R4. The emitter of the second transistor Q2 is connected to ground through the fifth resistor R5 and to MCU_IO through the sixth resistor R6. The collector of the second transistor Q2 is connected to MCU_VCC.

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

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