A lithium battery charging and discharging status indication circuit

Abstract

A lithium battery charge and discharge status indication circuit. The present invention relates to a first status indicator light and a second status indicator light; an IC control chip, having a first signal output terminal, a second signal output terminal and a third signal output terminal, when the lithium battery is being charged, the first signal output terminal outputs a high level, when the lithium battery is fully charged, the first signal output terminal outputs a low level, when the lithium battery is overcharged, the second signal output terminal outputs a low level, when the lithium battery is being discharged, the third signal output terminal outputs a high level, when the lithium battery is undervoltage, the third signal output terminal outputs a PWM signal. The lithium battery charge and discharge status indication circuit of the above embodiment uses two status indicator lights, which can respectively display the working status of the lithium battery in the five states of charging, full, overcharge, discharge, and undervoltage, with a simple structure and clear display.

Description

Technical Field

[0001] The invention relates to the field of lithium batteries, and in particular to a lithium battery charge and discharge state indicating circuit. Background Art

[0002] With the change of energy technology and the development of emerging technologies, the global production of lithium-ion batteries has entered a period of rapid growth. Lithium-ion batteries have become the battery system with the best comprehensive performance at present, with high specific energy, high cycle life, small size, light weight, no memory effect, no pollution, etc. It has rapidly developed into a new generation of energy storage power supply, widely used in information technology, new energy vehicles, power tools, consumer electronics and other fields. Due to the relatively active chemical properties of lithium-ion batteries, they also have their own safety needs. The use of lithium battery protection boards can further enhance the safety of lithium batteries.

[0003] The lithium battery protection board has functions such as charging monitoring, charging overvoltage detection, discharge monitoring, and discharge undervoltage detection, which can effectively protect the lithium battery and improve the safety of the product. However, these functions are all operated by a dedicated IC chip, and the existing lithium battery pack cannot clearly know what state it is in, which will cause confusion to operators during testing or end consumers during use. It is impossible to clearly and effectively judge whether the battery is fully charged or whether the power has been used up during use. Summary of the invention

[0004] Based on this, it is necessary to provide a lithium battery charge and discharge status indication circuit to address the problem that the status of the lithium battery is not clear enough.

[0005] A lithium battery charge and discharge status indication circuit, comprising:

[0006] A first status indicator light and a second status indicator light;

[0007] The IC control chip has a first signal output terminal, a second signal output terminal and a third signal output terminal. When the lithium battery is being charged, the first signal output terminal outputs a high level. When the lithium battery is fully charged, the first signal output terminal outputs a low level. When the lithium battery is overcharged, the second signal output terminal outputs a low level. When the lithium battery is being discharged, the third signal output terminal outputs a high level. When the lithium battery is under-voltage, the third signal output terminal outputs a PWM signal.

[0008] a first MOS transistor, wherein a gate of the first MOS transistor is connected to the first signal output terminal, and a drain of the first MOS transistor is connected to the second signal output terminal;

[0009] a first triode, wherein the base of the first triode is connected to the source of the first MOS tube;

[0010] A second MOS tube, connected to the first triode, and electrically connected to the positive electrodes of the first status indicator light and the second status indicator light;

[0011] A second triode connected between the first triode and the cathode of the first status indicator light;

[0012] A third transistor, connected to the second status indicator light and the source of the first MOS transistor, and connected in parallel with the first transistor and the second transistor;

[0013] The third MOS tube is connected between the third signal output terminal and the cathode of the first status indicator light.

[0014] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0015] a thirteenth resistor, one end of which is connected to the base of the third transistor;

[0016] a nineteenth resistor, one end of which is connected to the base of the third transistor;

[0017] a fifth capacitor connected in parallel with the nineteenth resistor;

[0018] a fourth diode, the anode of which is electrically connected to the other end of the nineteenth resistor;

[0019] The eighteenth diode has an anode electrically connected to the cathode of the fourth diode, and a cathode electrically connected to the collector of the second transistor.

[0020] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0021] The ninth diode is connected between the cathode of the fourth diode and the drain of the thirteenth MOS tube.

[0022] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0023] a twentieth resistor, one end of which is connected to the base of the second triode, and the other end of which is connected to the emitter of the second triode;

[0024] A sixth capacitor connected in parallel with the second resistor

[0025] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0026] a twenty-second resistor, one end of which is connected to the base of the first transistor, and the other end of which is connected to the emitter of the first transistor;

[0027] A seventh capacitor is connected in parallel with the twenty-second resistor.

[0028] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0029] A twenty-sixth diode is connected between the first signal output terminal and the first MOS transistor.

[0030] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0031] A third resistor is connected in parallel between the gate and the source of the second MOS tube;

[0032] A thirty-third capacitor, connected in parallel with the third resistor;

[0033] A nineteenth diode is connected in parallel with the third resistor and the thirty-third capacitor.

[0034] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0035] An eighteenth resistor is connected in parallel between the gate and the source of the third MOS tube;

[0036] a third capacitor connected in parallel with the eighteenth resistor;

[0037] The eighth transistor is connected in parallel with the eighteenth resistor and the third capacitor.

[0038] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0039] The fifteenth resistor is connected between the third signal output terminal and the third MOS tube.

[0040] In one preferred embodiment, the lithium battery charge and discharge status indication circuit further includes:

[0041] The first resistor and the second resistor are connected in parallel with the first status indicator light and the second status indicator light respectively.

[0042] The lithium battery charge and discharge status indication circuit of the above embodiment of the present invention uses two status indicator lights to respectively display the working status of the lithium battery in five states: charging, full, overcharge, discharge, and undervoltage. It has a simple structure and clear display. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The figure is a schematic diagram of the circuit structure of a lithium battery charge and discharge status indication circuit in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0047] like Figure 1 As shown, the present invention discloses a lithium battery charge and discharge status indication circuit 100, including a first status indicator LED1A, a second status indicator LED1B, an IC control chip (not shown), a first MOS tube Q12, a first transistor Q7, a second MOS tube Q2, a second transistor Q6, a third transistor Q5 and a third MOS tube Q3;

[0048] The IC control chip has a first signal output terminal C0, a second signal output terminal CHG and a third signal output terminal LED+. When the lithium battery is being charged, the first signal output terminal C0 outputs a high level. When the lithium battery is fully charged, the first signal output terminal C0 outputs a low level. When the lithium battery is overcharged, the second signal output terminal CHG outputs a low level. When the lithium battery is discharging, the third signal output terminal LED+ outputs a high level. When the lithium battery is undervoltage, the third signal output terminal LED+ outputs a PWM signal.

[0049] a first MOS transistor Q12, wherein a gate of the first MOS transistor Q12 is connected to the first signal output terminal C0, and a drain of the first MOS transistor Q12 is connected to the second signal output terminal CHG;

[0050] a first transistor Q7, wherein the base of the first transistor Q7 is connected to the source of the first MOS transistor Q12;

[0051] The second MOS transistor Q2 is connected to the first transistor Q7 and is electrically connected to the positive electrodes of the first status indicator LED1A and the second status indicator LED1B;

[0052] A second transistor Q6 is connected between the first transistor Q7 and the cathode of the first status indicator LED1A;

[0053] A third transistor Q5 is connected to the second state indicator LED1B and the source of the first MOS transistor Q12, and is connected in parallel with the first transistor Q7 and the second transistor Q6;

[0054] The third MOS tube Q3 is connected between the third signal output terminal LED+ and the cathode of the first status indicator LED1A.

[0055] Specifically, the lithium battery charge and discharge status indication circuit 100 also includes: a thirteenth resistor R13, a nineteenth resistor R19, a fifth capacitor C5, a fourth diode D4 and an eighteenth diode D18, one end of the thirteenth resistor R13 is connected to the base of the third transistor Q5, and one end of the nineteenth resistor R19 is connected to the base of the third transistor Q5; the fifth capacitor C5 is connected in parallel with the nineteenth resistor R19; the anode of the fourth diode D4 is electrically connected to the other end of the nineteenth resistor R19; the anode of the eighteenth diode D18 is electrically connected to the cathode of the fourth diode D4, and the cathode is electrically connected to the collector of the second transistor Q6.

[0056] The ninth diode D9 is connected between the cathode of the fourth diode D4 and the drain of the third MOS transistor Q3.

[0057] Specifically, the lithium battery charge and discharge status indication circuit 100 further includes:

[0058] A twentieth resistor R20 has one end connected to the base of the second transistor D2, and the other end connected to the emitter of the second transistor D2;

[0059] The sixth capacitor C6 is connected in parallel with the second resistor R2

[0060] a twenty-second resistor R22, one end of which is connected to the base of the first transistor Q7, and the other end of which is connected to the emitter of the first transistor Q7;

[0061] The seventh capacitor C7 is connected in parallel with the twenty-second resistor R22.

[0062] A twenty-sixth diode D26 is connected between the first signal output terminal C0 and the first MOS transistor Q12.

[0063] A third resistor R3 is connected in parallel between the gate and the source of the second MOS transistor Q2;

[0064] A thirty-third capacitor C33, connected in parallel with the third resistor R3;

[0065] The nineteenth diode D19 is connected in parallel with the third resistor R3 and the thirty-third capacitor C33.

[0066] An eighteenth resistor R18 is connected in parallel between the gate and the source of the third MOS transistor Q3;

[0067] A third capacitor C3 is connected in parallel with the eighteenth resistor R18;

[0068] The eighth transistor D8 is connected in parallel with the eighteenth resistor R18 and the third capacitor C3.

[0069] The fifteenth resistor R15 is connected between the third signal output terminal LED+ and the third MOS transistor Q3.

[0070] The first resistor R1 and the second resistor R2 are connected in parallel with the first status indicator LED1A and the second status indicator LED1B respectively.

[0071] During lithium battery charging:

[0072] When the lithium battery is in the charging state, the first signal output terminal C0 of the lithium battery charge and discharge state indication circuit 100 outputs a high level, the first MOS tube Q12 is turned on, the first transistor Q7 is turned on, the second transistor Q6 is turned off, the first state indicator LED1A is not lit, the third transistor Q5 is turned on, and the second state indicator LED1B is lit.

[0073] When the lithium battery is fully charged, the first signal output terminal C0 outputs a low level, the first MOS tube Q12 is turned off, the first transistor Q7 is turned off, the second transistor Q6 is turned on, and the first state indicator LED1A is on. Since the resistance values ​​of the fourth diode D4, the eighteenth diode D18, and the second transistor Q6 are much smaller than the 113th resistor R13 and the nineteenth resistor R19, the second state indicator LED1B is not on.

[0074] When the lithium battery is in an overcharge state: the second signal output terminal CHG outputs a low level, the first MOS tube Q12 is turned off, the first transistor Q7 is turned off, the second transistor Q6 is turned on, and the first state indicator LED1A is on. Since the resistance values ​​of the fourth diode D4, the eighteenth diode D18, and the second transistor Q6 are much smaller than the thirteenth resistor R13 and the nineteenth resistor R19, the second state indicator LED1B is not on.

[0075] Discharge process:

[0076] When the lithium battery is discharging, the third signal output terminal LED+ outputs a high level, the third MOS tube Q3 is turned on, the first status indicator LED1A is on, the first signal output terminal C0 outputs a low level, and the second status indicator LED1B is off.

[0077] When the lithium battery is under-voltage: the third signal output terminal LED+ outputs a PWM signal, Q3 turns on, the first status indicator LED1A flashes, the first signal output terminal C0 outputs a low level, and the second status indicator LED1B does not light up.

[0078] The lithium battery charge and discharge status indication circuit of the above embodiment of the present invention uses two status indicator lights to respectively display the working status of the lithium battery in five states: charging, full, overcharge, discharge, and undervoltage. It has a simple structure and clear display.

[0079] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A lithium battery charge and discharge status indication circuit, characterized in that: include: A first status indicator light and a second status indicator light; The IC control chip has a first signal output terminal, a second signal output terminal and a third signal output terminal. When the lithium battery is being charged, the first signal output terminal outputs a high level. When the lithium battery is fully charged, the first signal output terminal outputs a low level. When the lithium battery is overcharged, the second signal output terminal outputs a low level. When the lithium battery is being discharged, the third signal output terminal outputs a high level. When the lithium battery is under-voltage, the third signal output terminal outputs a PWM signal. a first MOS transistor, wherein a gate of the first MOS transistor is connected to the first signal output terminal, and a drain of the first MOS transistor is connected to the second signal output terminal; a first triode, wherein the base of the first triode is connected to the source of the first MOS tube; A second MOS tube, connected to the first triode, and electrically connected to the positive electrodes of the first status indicator light and the second status indicator light; A second triode connected between the first triode and the cathode of the first status indicator light; a third transistor, connected to the second state indicator light and the source of the first MOS transistor, and connected in parallel with the first transistor and the second transistor; A first resistor and a second resistor are connected in parallel with the first status indicator light and the second status indicator light respectively; The third MOS tube is connected between the third signal output terminal and the cathode of the first status indicator light.

2. The lithium battery charge and discharge status indication circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: a thirteenth resistor, one end of which is connected to the base of the third transistor; a nineteenth resistor, one end of which is connected to the base of the third transistor; a fifth capacitor connected in parallel with the nineteenth resistor; a fourth diode, the anode of which is electrically connected to the other end of the nineteenth resistor; The eighteenth diode has an anode electrically connected to the cathode of the fourth diode, and a cathode electrically connected to the collector of the second transistor.

3. The lithium battery charge and discharge status indication circuit according to claim 2, characterized in that: The lithium battery charge and discharge status indication circuit also includes: A ninth diode is connected between the cathode of the fourth diode and the drain of the third MOS tube.

4. The lithium battery charge and discharge status indication circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: a twentieth resistor, one end of which is connected to the base of the second triode, and the other end of which is connected to the emitter of the second triode; A sixth capacitor is connected in parallel with the second resistor.

5. The lithium battery charge and discharge status indication circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: a twenty-second resistor, one end of which is connected to the base of the first transistor, and the other end of which is connected to the emitter of the first transistor; A seventh capacitor is connected in parallel with the twenty-second resistor.

6. The lithium battery charge and discharge status indicating circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: A twenty-sixth diode is connected between the first signal output terminal and the first MOS transistor.

7. The lithium battery charge and discharge status indicating circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: A third resistor is connected in parallel between the gate and the source of the second MOS tube; A thirty-third capacitor, connected in parallel with the third resistor; A nineteenth diode is connected in parallel with the third resistor and the thirty-third capacitor.

8. The lithium battery charge and discharge status indication circuit according to claim 1, characterized in that: The lithium battery charge and discharge status indication circuit also includes: An eighteenth resistor is connected in parallel between the gate and the source of the third MOS tube; a third capacitor connected in parallel with the eighteenth resistor; The eighth transistor is connected in parallel with the eighteenth resistor and the third capacitor.

9. The lithium battery charge and discharge status indicating circuit according to claim 8, characterized in that: The lithium battery charge and discharge status indication circuit also includes: The fifteenth resistor is connected between the third signal output terminal and the third MOS tube.

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