Low-side-driven lithium battery protection load detection circuit
By configuring an interrupt input on the MCU's load_check pin and combining it with a detection circuit composed of MOSFETs, diodes, Zener diodes, resistors, and capacitors, the problem of insufficient load detection accuracy and response speed in low-side driven lithium battery protection circuits is solved, enabling fast load detection and lithium battery protection logic judgment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YISIYUAN SEMICON NANJING CO LTD
- Filing Date
- 2025-03-27
- Publication Date
- 2026-04-10
AI Technical Summary
The existing low-side drive lithium battery protection circuits have insufficient load detection accuracy and response speed, which cannot meet the high requirements of the new energy industry.
By configuring the load_check pin of the MCU as an interrupt input, and combining it with a detection circuit composed of MOSFETs, diodes, Zener diodes, resistors, and capacitors, the load connection status is determined by the change in the PACK- terminal voltage, thus realizing logical judgment.
It improves the accuracy and response speed of load detection, enabling the MCU to quickly intervene in the lithium battery protection logic judgment.
Smart Images
Figure CN224111158U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to, in particular provides a low-side driven lithium battery protection load detection circuit, by detecting PACK- voltage change to determine the load access, after the MCU pin is configured as an interrupt input, so that when the load access occurs MCU can intervene in logical judgment. BACKGROUND
[0002] At present, for low-side driven lithium battery protection circuit in the basic function has been relatively mature, but the precision of load detection, response speed still needs to be further optimized, with the continuous development of new energy industry, the requirement of load detection is also more and more high, so the present application provides an improved method, under the condition that the analog front-end chip does not have load detection function, load detection function is provided. SUMMARY
[0003] A low-side driven lithium battery protection load detection circuit, comprising a first MOS tube Q1, a first diode D1, a first voltage stabilizing tube ZD1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1. Wherein the drain of the first MOS tube Q1 is connected with the 3V3 of the MCU through the first resistor R1 and is connected with the load_check pin of the MCU, the gate of the first MOS tube Q1 is connected with the negative electrode of the first diode D1 through the second resistor R2 and is connected to the negative electrode of the first voltage stabilizing tube ZD1 through the first capacitor C1 and is connected to the ground at the same time, the source of the first MOS tube Q1 is connected to the gate of the first MOS tube Q1 through the third resistor R3 and is connected to the ground at the same time, the positive electrode of the first diode D1 is connected to PACK-, the positive electrode of the first voltage stabilizing tube ZD1 is connected to the ground.
[0004] It should be noted that in the present application, the load_check pin is an interrupt input pin of the MCU, which is used for detecting the load access state; PACK- is the negative end of the load in the low-side driven circuit, that is, the power ground end; MCU_3V3 is the power supply end of the MCU, which provides working voltage for the MCU and its related circuits. BRIEF DESCRIPTION OF DRAWINGS
[0005] Figure 1 The low-side driven lithium battery protection load detection circuit in the present application. DETAILED DESCRIPTION
[0006] The low-side driving lithium battery protection load detection circuit comprises a first MOS tube Q1, a first diode D1, a first voltage stabilizing tube ZD1, a first resistor R1, a second resistor R2, a third resistor R3 and a first capacitor C1. The drain of the first MOS tube Q1 is connected to the 3V3 of the MCU through the first resistor R1 and is connected to the load_check pin of the MCU, the gate of the first MOS tube Q1 is connected to the negative electrode of the first diode D1 through the second resistor R2 and is connected to the negative electrode of the first voltage stabilizing tube ZD1 through the first capacitor C1, the source of the first MOS tube Q1 is connected to the gate of the first MOS tube Q1 through the third resistor R3 and is grounded, the positive electrode of the first diode D1 is connected to PACK-, and the positive electrode of the first voltage stabilizing tube ZD1 is connected to the ground.
[0007] The circuit realizes logical judgment by detecting the voltage of the PACK- end. When the circuit is not connected to a load, the PACK- is suspended or at a negative level, the MOS tube Q1 does not satisfy the conduction condition, and the load_check end will remain at a high level. When the circuit is connected to a load, the PACK- is at a positive voltage, the MOS tube Q1 satisfies the conduction condition, and the load_check end will be pulled down to a low level. The load_check is connected to the IO of the MCU, and is configured to make the MCU quickly intervene in the logical judgment of the lithium battery protection after the interruption.
[0008] It is apparent for those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the present application being indicated by the appended claims rather than by the foregoing description, and it is intended that all changes and modifications which come within the meaning and range of equivalency of the claims are resolvable by the following claims. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.
[0009] In addition, it should be understood that, although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the specification is described only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be combined appropriately to form other manners that those skilled in the art can understand.
Claims
1. A low-side driven lithium battery protection load detection circuit, characterized in that: The circuit includes a first MOSFET Q1, a first diode D1, a first Zener diode ZD1, a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The drain of the first MOSFET Q1 is connected to the 3V3 of the MCU through the first resistor R1 and is also connected to the load_check pin of the MCU. The gate of the first MOSFET Q1 is connected to the cathode of the first diode D1 through the second resistor R2, and is also grounded through the first capacitor C1 and connected to the cathode of the first Zener diode ZD1. The source of the first MOSFET Q1 is connected to the gate of the first MOSFET Q1 through the third resistor R3 and is also grounded. The anode of the first diode D1 is connected to PACK-, and the anode of the first Zener diode ZD1 is connected to ground.
2. The low-side driven lithium battery protection load detection circuit according to claim 1, characterized in that: In the circuit, the load_check pin serves as an interrupt input pin for the MCU, PACK- is the negative terminal of the load in the low-side drive circuit, and MCU_3V3 is the power supply terminal for the MCU.