A MOS damage detection circuit for lithium batteries

Abstract

The utility model discloses a MOS damage detection circuit for a lithium battery, comprising a resistor R134, a resistor R5, a resistor R8, a resistor R163, a resistor R200, a resistor R141, a resistor R154, a resistor R167, a resistor R168, a diode D27, a diode D28, a transistor Q26, a transistor Q27, a transistor Q34 and a MOS tube QD15, wherein one end of the resistor R134 is connected to a capacitor C16, a resistor R163, a resistor R8, an emitter of the transistor Q27 and a +12V voltage. The MOS damage detection circuit for a lithium battery of the utility model can detect the state of the MOS in real time during the operation of the equipment, and timely disconnect the current through a single chip microcomputer at the moment when the MOS is damaged, so as to protect the equipment in real time, and the application is more flexible and real-time detection is performed.

Description

Technical Field

[0001] The utility model relates to the technical field of battery detection, in particular to a MOS damage detection circuit for a lithium battery. Background Art

[0002] Currently, the only method that can be searched on the website is the detection method of MOS damage, which uses a multimeter to detect the quality of MOS. There is no circuit for MOS damage detection.

[0003] The original method can only test MOS damage when the device is powered off. MOS damage cannot be directly detected during device operation. MOS damage cannot be detected in real time. The operation is complicated and not flexible enough. Utility Model Content

[0004] The purpose of the utility model is to provide a MOS damage detection circuit for a lithium battery to solve the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A MOS damage detection circuit for a lithium battery comprises a resistor R134, a resistor R5, a resistor R8, a resistor R163, a resistor R200, a resistor R141, a resistor R154, a resistor R167, a resistor R168, a diode D27, a diode D28, a transistor Q26, a transistor Q27, a transistor Q34 and a MOS transistor QD15, wherein one end of the resistor R134 is connected to a capacitor C16, a resistor R163, a resistor R8, an emitter of the transistor Q27 and a +12V voltage, the other end of the resistor R134 is connected to the resistor R164 and the emitter of the transistor Q26, the base of the transistor Q26 is connected to the resistor R5 and the other end of the resistor R8, the other end of the transistor Q26 is connected to the positive electrode of the diode D27, the negative electrode of the diode D27 is connected to the positive electrode of the diode D28 and the resistor R141, and the positive electrode of the diode D28 is connected to the positive electrode of the diode D28. The other end of the resistor R141 is connected to the drain of the MOS tube QD15 and the ground terminal, the other end of the diode D28 is connected to the gate of the MOS tube QD15 through the resistor R200, the source of the MOS tube QD15 is grounded, the other end of the resistor R5 is grounded, the other end of the resistor R164 is connected to the other end of the capacitor C16, the other end of the resistor R163 and the base of the transistor Q27, the collector of the transistor Q27 is connected to the diode D23, the other end of the diode D23 is connected to the resistor R167, the other end of the resistor R167 is connected to the resistor R168 and the base of the transistor Q34, the collector of the transistor Q34 is connected to the resistor R154 and the COM_DET pin of the single chip computer, the other end of the resistor R154 is connected to the voltage VCC_MCC, and the other end of the resistor R168 is connected to the emitter of the transistor Q34 and the ground terminal.

[0007] As a further technical solution of the utility model: the transistor Q26 is a PNP transistor.

[0008] As a further technical solution of the utility model: the transistor Q27 is a PNP transistor.

[0009] As a further technical solution of the utility model: the transistor Q34 is an NPN transistor.

[0010] As a further technical solution of the present utility model: the MOS tube QD15 is a P-MOS tube.

[0011] Compared with the prior art, the beneficial effects of the utility model are:

[0012] The MOS damage detection circuit of the utility model lithium battery can detect the state of MOS in real time during the operation of the equipment, and promptly cut off the current through the single chip microcomputer at the moment of MOS damage, so as to protect the equipment in real time, and the application is more flexible and real-time detection is possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is the principle diagram of the utility model. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the utility model are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0015] Reference Figure 1A MOS damage detection circuit for a lithium battery comprises a resistor R134, a resistor R5, a resistor R8, a resistor R163, a resistor R200, a resistor R141, a resistor R154, a resistor R167, a resistor R168, a diode D27, a diode D28, a transistor Q26, a transistor Q27, a transistor Q34 and a MOS transistor QD15, wherein one end of the resistor R134 is connected to a capacitor C16, a resistor R163, a resistor R8, an emitter of the transistor Q27 and a +12V voltage, the other end of the resistor R134 is connected to the resistor R164 and the emitter of the transistor Q26, the base of the transistor Q26 is connected to the other end of the resistor R5 and the resistor R8, the other end of the transistor Q26 is connected to the positive electrode of the diode D27, the negative electrode of the diode D27 is connected to the positive electrode of the diode D28 and the resistor R1 41, the other end of the resistor R141 is connected to the drain of the MOS tube QD15 and the ground terminal, the other end of the diode D28 is connected to the gate of the MOS tube QD15 through the resistor R200, the source of the MOS tube QD15 is grounded, the other end of the resistor R5 is grounded, the other end of the resistor R164 is connected to the other end of the capacitor C16, the other end of the resistor R163 and the base of the transistor Q27, the collector of the transistor Q27 is connected to the diode D23, the other end of the diode D23 is connected to the resistor R167, the other end of the resistor R167 is connected to the resistor R168 and the base of the transistor Q34, the collector of the transistor Q34 is connected to the resistor R154 and the COM_DET pin of the single chip computer, the other end of the resistor R154 is connected to the voltage VCC_MCC, and the other end of the resistor R168 is connected to the emitter of the transistor Q34 and the ground terminal.

[0016] Among them, transistor Q4 and transistor Q7 are PNP transistors, and transistor Q10 and transistor Q12 are NPN transistors.

[0017] Here’s how it works:

[0018] The MOS damage detection circuit can be used in the protection circuit of lithium batteries, where QD15 is the MOS that needs to be detected. Under normal circumstances, the GS pole resistance of the MOS will be very large, generally in several megohms. When the MOS is damaged, it will become hundreds of thousands of ohms. At this time, QD15 and R141 in parallel will make the collector voltage of Q26 smaller and the emitter voltage larger. At this time, Q27 and Q34 are driven normally, and the COM DET pin of the microcontroller will be pulled low. The microcontroller executes the corresponding program to disconnect the circuit controlled by QD15, thereby protecting the protection board and the lithium battery, and playing a role in safety protection. The diodes are used for anti-reverse, capacitor filtering, and resistor voltage division.

[0019] When the MOS is damaged, the GS pole internal resistance of the MOS will become smaller. Based on this, the present invention sets two sets of transistor drives and adopts a suitable voltage division ratio. When the MOS is normal, the GS pole internal resistance of QD15 is large, and the Q26 transistor is normally turned on at this time, and the mos works normally at this time; when the MOS is damaged, the GS pole internal resistance of QD15 becomes smaller, and Q27 is normally driven and turned on at this time, and Q34 is also normally driven. At this time, the CMOSDET pin of the single-chip microcomputer will be pulled low, and the single-chip microcomputer executes corresponding actions to disconnect the discharge port, thereby playing a protective role.

[0020] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0021] In addition, it should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment have also been appropriately combined to form other implementation modes that are easy for those skilled in the art to understand.

Claims

1. A MOS damage detection circuit for a lithium battery, comprising a resistor R134, a resistor R5, a resistor R8, a resistor R163, a resistor R200, a resistor R141, a resistor R154, a resistor R167, a resistor R168, a diode D27, a diode D28, a transistor Q26, a transistor Q27, a transistor Q34 and a MOS transistor QD15, characterized in that: One end of the resistor R134 is connected to the capacitor C16, the resistor R163, the resistor R8, the emitter of the transistor Q27 and the +12V voltage, the other end of the resistor R134 is connected to the resistor R164 and the emitter of the transistor Q26, the base of the transistor Q26 is connected to the resistor R5 and the other end of the resistor R8, the other end of the transistor Q26 is connected to the positive electrode of the diode D27, the negative electrode of the diode D27 is connected to the positive electrode of the diode D28 and the resistor R141, the other end of the resistor R141 is connected to the drain of the MOS tube QD15 and the ground terminal, the other end of the diode D28 is connected to the gate of the MOS tube QD15 through the resistor R200, The source of OS tube QD15 is grounded, the other end of resistor R5 is grounded, the other end of resistor R164 is connected to the other end of capacitor C16, the other end of resistor R163 and the base of transistor Q27, the collector of transistor Q27 is connected to diode D23, the other end of diode D23 is connected to resistor R167, the other end of resistor R167 is connected to resistor R168 and the base of transistor Q34, the collector of transistor Q34 is connected to resistor R154 and the COM_DET pin of the microcontroller, the other end of resistor R154 is connected to voltage VCC_MCC, and the other end of resistor R168 is connected to the emitter of transistor Q34 and the ground.

2. A MOS damage detection circuit for a lithium battery according to claim 1, characterized in that: The transistor Q26 is a PNP transistor.

3. The MOS damage detection circuit of a lithium battery according to claim 1, characterized in that: The transistor Q27 is a PNP transistor.

4. The MOS damage detection circuit of a lithium battery according to claim 1, characterized in that: The transistor Q34 is an NPN transistor.

5. A MOS damage detection circuit for a lithium battery according to claim 4, characterized in that: The MOS tube QD15 is a P-MOS tube.

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