A low-side driven lithium battery protection charger detection circuit
By designing a detection circuit that includes transistors and diodes, the charger connection status is determined by the change in PACK terminal voltage. This solves the problem of insufficient charger detection accuracy and response speed in low-side driven lithium battery protection circuits, and realizes fast logic judgment and protection functions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YISIYUAN SEMICON NANJING CO LTD
- Filing Date
- 2025-03-21
- Publication Date
- 2026-05-26
AI Technical Summary
The existing charger detection accuracy and response speed of low-side drive lithium battery protection circuits are insufficient, failing to meet the high requirements of the new energy industry.
By designing a detection circuit that includes specific transistors and diodes, the charging connection status is determined by the change in PACK terminal voltage, and the interrupt input pin of the MCU is configured to achieve fast logic judgment.
It improves the accuracy and response speed of charger detection, ensuring that the MCU can quickly intervene in the lithium battery protection logic judgment.
Smart Images
Figure CN224287111U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to and specifically provides a low-side driven lithium battery protection charger detection circuit, which determines the charger connection by detecting the voltage change of the PACK-. After configuring the MCU pin as an interrupt input, the MCU can intervene in the logic judgment when a load is connected. Background Technology
[0002] Currently, the basic functions of low-side drive lithium battery protection circuits are relatively mature, but the accuracy and response speed of charger detection still need further optimization. With the continuous development of the new energy industry, the requirements for charger detection are also getting higher and higher. Therefore, this invention provides an improved method to provide charger detection function when the analog front-end chip does not have charger detection function. Summary of the Invention
[0003] A low-side driven lithium battery protection charger detection circuit, characterized in that it includes a first transistor Q1, a second transistor Q2, a first diode D1, 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 emitter of the first transistor Q1 is connected to MCU_3V3 and then to its base via the first resistor R1. The collector of the first transistor Q1 is connected to CHG_DET via the third resistor R3 and grounded via the fourth resistor R4. The base of the first transistor Q1 is connected to the collector of the second transistor Q2 via the second resistor R2. The base of the second transistor Q2 is grounded via the fifth resistor R5 and then connected to its emitter via the sixth resistor R6. The emitter of the second transistor Q2 is connected to the first diode D1, and the cathode of the first diode D1 is connected to PACK-.
[0004] It should be noted that in this application, CHG_DET is used as an interrupt input pin of the MCU to detect the charger connection status; PACK- is the negative terminal of the load in the low-side drive circuit, i.e., the power ground terminal; MCU_3V3 is the power supply terminal of the MCU, which provides the operating voltage to the MCU and its related circuits. Attached Figure Description
[0005] Figure 1 This is a circuit diagram of a low-side driven lithium battery charger detection circuit in this invention. Detailed Implementation
[0006] A low-side driven lithium battery protection charger detection circuit, characterized in that it includes a first transistor Q1, a second transistor Q2, a first diode D1, 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 emitter of the first transistor Q1 is connected to MCU_3V3 and then to its base via the first resistor R1. The collector of the first transistor Q1 is connected to CHG_DET via the third resistor R3 and grounded via the fourth resistor R4. The base of the first transistor Q1 is connected to the collector of the second transistor Q2 via the second resistor R2. The base of the second transistor Q2 is grounded via the fifth resistor R5 and then connected to its emitter via the sixth resistor R6. The emitter of the second transistor Q2 is connected to the first diode D1, and the cathode of the first diode D1 is connected to PACK-.
[0007] This circuit performs logic judgment by detecting the voltage at the PACK- terminal. When no charger is connected to the circuit, PACK- is floating, transistor Q2 does not meet the conduction condition, and the CHG_DET terminal will remain at a low level. When a charger is connected to the circuit, PACK- is negative, transistor Q2 meets the conduction condition, and transistor Q1 is further turned on. The CHG_DET terminal will be pulled up to a high level. CHG_DET is connected to the MCU's I / O. After being configured as an interrupt, it can enable the MCU to quickly intervene in the lithium battery protection logic judgment.
[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 low-side driven lithium battery protection charger detection circuit, characterized in that: The circuit includes a first transistor Q1, a second transistor Q2, a first diode D1, 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 emitter of the first transistor Q1 is connected to MCU_3V3 and then to the base of the first transistor Q1 via the first resistor R1. The collector of the first transistor Q1 is connected to CHG_DET via the third resistor R3 and grounded via the fourth resistor R4. The base of the first transistor Q1 is connected to the collector of the second transistor Q2 via the second resistor R2. The base of the second transistor Q2 is grounded via the fifth resistor R5 and then connected to the emitter of the second transistor Q2 via the sixth resistor R6. The emitter of the second transistor Q2 is connected to the first diode D1, and the cathode of the first diode D1 is connected to PACK-.
2. The detection circuit for a low-side driven lithium battery protection charger according to claim 1, characterized in that: In the circuit, the MCU's IO port is configured as the interrupt input CHG_DET pin, PACK- is the negative terminal of the load in the low-side drive circuit, and MCU_3V3 comes from the MCU's power supply terminal.