Lithium battery pack electric quantity display time-delay circuit

Abstract

The utility model discloses an electric quantity display delay circuit for a lithium battery pack. The electric quantity display delay circuit comprises a touch switch, an MOS tube Q6, a triode Q5, a first group of divider resistors, a diode D5, a capacitor C9, a resistor R3 and a plurality of display branches, the first group of voltage dividing resistors comprises a resistor R1 and a resistor R2, the first group of voltage dividing resistors and the touch switch are connected in series between the positive electrode and the negative electrode of the battery, one end of the resistor R2 is connected with one end of the capacitor C9, one end of the resistor R3 and the source electrode of the MOS tube Q6, the other end of the resistor R2 is connected with the positive electrode of the diode D5, the negative electrode of the diode D5, the other end of the capacitor C9 and the other end of the resistor R3 are connected with the grid electrode of the MOS tube Q6, and the drain electrode of the MOS tube Q6 is connected with the base electrode of the triode Q5; the emitter of the triode Q5 is connected with the power supply anode; each display branch is connected in parallel between the collector of the triode Q5 and the negative electrode of the power supply. The device is simple in structure, convenient to use and low in cost, saves power consumption, and enables the cost utilization rate of new energy to be higher.

Description

Technical Field

[0001] The utility model belongs to the technical field of power supply lithium battery packs, and in particular relates to a lithium battery pack power display delay circuit. Background Art

[0002] Common garden tools require the use of new energy lithium battery packs. When using lithium battery packs, users need to know the battery pack's power level first. Traditional power display is through IC design, collecting current and voltage, using integral method to calculate SOC and display the battery pack power through LCD display. Traditional battery pack power display is too complicated, and the circuit system and software system construction cost is too high, which increases the manufacturing cost of some convenient new energy.

[0003] The current lithium battery pack power display circuit requires at least a single-chip microcontroller (MCU) and a complex charge detection and calculation system within the circuit system. It also needs to use a large LCD display data conversion to reflect the battery pack power status. Although it is relatively sophisticated and high-end, the product cost is too high and is not conducive to saving resources. Summary of the Invention

[0004] Purpose of the invention: In order to solve the problem of high cost of lithium battery pack power display in the prior art, the utility model provides a lithium battery pack power display delay circuit.

[0005] Technical solution: A lithium battery pack power display delay circuit includes a touch switch, a MOS tube Q6, a transistor Q5, a first group of voltage-dividing resistors, a diode D5, a capacitor C9, a resistor R3 and multiple display branches, and the multiple display branches are connected in parallel; the first group of voltage-dividing resistors includes resistors R1 and R2, and the resistors R1, R2 and the touch switch are connected in series between the positive and negative poles of the battery. One end of the resistor R2 is connected to one end of the capacitor C9, one end of the resistor R3 and the source of the MOS tube Q6, and the other end of the resistor R2 is connected to the positive pole of the diode D5. The negative pole of the diode D5, the other end of the capacitor C9 and the other end of the resistor R3 are all connected to the gate of the MOS tube Q6. The drain of the MOS tube Q6 is connected to the base of the transistor Q5 via the current-limiting resistor R4, and the emitter of the transistor Q5 is connected to the positive pole of the power supply; one end of the display branch is connected to the collector of the transistor Q5, and the other end is connected to the negative pole of the power supply; the display branch includes a light-emitting diode and a voltage-dividing resistor, and the voltages divided by the voltage-dividing resistors of the multiple display branches are different.

[0006] Furthermore, the display branch also includes a driving chip, a current limiting resistor and a shunt resistor. The voltage dividing resistor is connected between the positive and negative poles of the power supply, and the divided voltage is connected to the driving chip. The output of the driving chip is connected to the shunt resistor and the current limiting resistor in sequence, and the light-emitting diode is connected in parallel with the shunt resistor.

[0007] Furthermore, there are three display branches, including a first display branch, a second display branch, and a third display branch. The voltages divided by the voltage-dividing resistors in the first display branch, the second display branch, and the third display branch decrease successively, and the output voltages of the driving chips in the first display branch, the second display branch, and the third display branch decrease successively.

[0008] Furthermore, the first display branch includes a second group of voltage-coupled resistors, the second display branch includes a third group of voltage-coupled resistors, and the third display branch includes a fourth group of voltage-coupled resistors. The second group of voltage-coupled resistors includes resistor R7 and resistor R8, the third group of voltage-coupled resistors includes resistor R11 and resistor R12, and the fourth group of voltage-coupled resistors includes resistor R14 and resistor R15. Resistors R7, R11, and R14 are connected to the negative pole of the power supply, and resistors R8, R12, and R15 are connected to the collector of transistor Q5. The resistance values ​​of resistors R7, R11, and R14 decrease successively, and the resistance values ​​of resistors R8, R12, and R15 are the same.

[0009] Furthermore, the resistance of the resistor R3 is adjustable.

[0010] Furthermore, the resistance values ​​of the resistors R7 and R8 are adjustable.

[0011] Furthermore, the resistance values ​​of the resistor R11 and the resistor R12 are adjustable.

[0012] Furthermore, the resistance values ​​of the resistor R14 and the resistor R15 are adjustable.

[0013] Furthermore, the MOS transistor Q6 is an NMOS transistor.

[0014] Furthermore, the transistor Q5 is a PNP transistor.

[0015] Compared to existing technologies, the lithium battery pack power display delay circuit provided by this utility model has a simple structure and is easy to use. The circuit construction eliminates the need for a single-chip microcontroller, a complex charge detection and calculation system, and an LCD display data conversion circuit. The power display automatically turns off after a period of time, further saving power and eliminating the need to manually turn off the display. This circuit allows lithium battery packs to achieve the desired power display function simply and conveniently while significantly reducing the cost of power display. This improves the cost efficiency of new energy resources, promotes sustainable consumption, and enhances awareness of carbon reduction and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the schematic diagram of the lithium battery pack power display delay circuit. DETAILED DESCRIPTION

[0017] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0018] A lithium battery pack power display delay circuit, such as Figure 1 As shown, it includes a touch switch S1, a MOS transistor Q6, a transistor Q5, a first set of voltage-dividing resistors, a diode D5, a capacitor C9, a resistor R3, and multiple display branches, and the multiple display branches are connected in parallel; the first set of voltage-dividing resistors includes resistors R1 and R2, and the resistors R1, R2, and the touch switch S1 are connected in series between the positive and negative electrodes of the battery. One end of the resistor R2 is connected to one end of the capacitor C9, one end of the resistor R3, and the source of the MOS transistor Q6. The other end of the resistor R2 is connected to the positive electrode of the diode D5. The negative electrode of the diode D5, the other end of the capacitor C9, and the other end of the resistor R3 are all connected to the gate of the MOS transistor Q6. The drain of the MOS transistor Q6 is connected to the base of the transistor Q5 via a current-limiting resistor R4. The emitter of the transistor Q5 is connected to the positive electrode of the power supply, and a resistor R51 is connected between the base and the emitter. One end of the display branch is connected to the collector of the transistor Q5, and the other end is connected to the negative electrode of the power supply. The display branch includes a light-emitting diode and a voltage-dividing resistor, and the voltage divided by the voltage-dividing resistor of each display branch is different. The MOS transistor Q6 is an NMOS transistor, and the transistor Q5 is a PNP transistor.

[0019] Taking the first display branch as an example, the display branch also includes a driver chip U2, a current limiting resistor R6 and a shunt resistor R5. The voltage dividing resistors R7 and R8 are connected between the positive and negative poles of the power supply. The divided voltage is connected to the driver chip U2 to provide voltage for the driver chip. The output of the driver chip is connected to the shunt resistor R5 and the current limiting resistor R6 in sequence, and the light-emitting diode D1 is connected in parallel with the shunt resistor R5.

[0020] In this embodiment, there are three display branches, each with a light-emitting diode, so a total of three lights can be illuminated. A different number of display branches can be configured as needed. For example, this embodiment includes a first display branch, a second display branch, and a third display branch. The voltages divided by the voltage divider resistors in the first, second, and third display branches decrease in sequence, and the output voltages of the driver chips in the first, second, and third display branches decrease in sequence. The three display branches include light-emitting diodes D1, D2, and D3, respectively.

[0021] The first display branch includes a second set of transformer resistors, the second display branch includes a third set of transformer resistors, and the third display branch includes a fourth set of transformer resistors. The second set of transformer resistors includes resistors R7 and R8. These resistors regulate the voltage to drive TL431 chip U2 to critical conduction, illuminating light-emitting diode D1. The third set of transformer resistors includes resistors R11 and R12. These resistors regulate the voltage to drive TL431 chip U3 to critical conduction, illuminating light-emitting diode D2. The fourth set of transformer resistors includes resistors R14 and R15. These resistors regulate the voltage to drive TL431 chip U4 to critical conduction, illuminating light-emitting diode D3. Resistors R7, R11, and R14 are connected to the negative terminal of the power supply, while resistors R8, R12, and R15 are connected to the collector of transistor Q5. The resistance values ​​of resistors R7, R11, and R14 decrease in descending order, while the resistance values ​​of resistors R8, R12, and R15 are the same. For example, in this embodiment, R7 = 42.2 kΩ, R11 = 34.8 kΩ, R14 = 32.4 kΩ, R8 = R12 = R15 = 215 kΩ. The threshold voltage for LED D1 to light up is 15.25 V, the threshold voltage for LED D3 to light up is 17.95 V, and the threshold voltage for LED D4 to light up is 19.09 V. The resistance values ​​of resistors R7, R8, R11, R12, R14, and R15 are adjustable, so that the threshold voltage for each LED to light up can be adjusted, achieving lighting at a specific power level.

[0022] The resistance of resistor R3 is adjustable. The larger the resistance of R3, the slower the voltage drop on capacitor C9, and the longer the display delay time. In this embodiment, the discharge delay time of C9 is: T RC =1 / RC=1 / (1*1000000)*(2.2 / 1000000)=2.2 seconds.

[0023] The touch switch S1 is turned on and activated when it is short-circuited with the positive pole of the battery. When in use, just press the touch switch S1, and the first group of voltage dividers R1 and R2 divide the voltage, and the capacitor C9 is charged by connecting the unidirectional diode D5. When the voltage of the capacitor C9 increases, the MOS tube Q6 drain is driven to output a drive control signal, and according to the voltage value of the battery, the light-emitting diodes in the display branch are driven to display, and the corresponding voltage value displays the corresponding number of light-emitting diodes. When the touch switch S1 is released, the diode D5 is reversely cut off, and the charge on the capacitor C9 is slowly discharged through the resistor R3, achieving a delay of about a few seconds, until the voltage drops to the point where the MOS tube Q6 cannot be driven, and the battery indicator light is turned off.

[0024] This embodiment can illuminate a corresponding number of LEDs based on the battery pack voltage and then delay extinguishing, letting the user know the battery pack's charge level. A battery voltage greater than the critical 19.09V indicates a full charge, with all three LEDs lighting up; a voltage between 17.95V and 19.08V indicates two-thirds charge, with two LEDs lighting up; a voltage between 15.25V and 17.95V indicates one-third charge, with only one LED lighting up; and a voltage below 15.25V indicates a dead battery, with no light illuminating. Therefore, this embodiment can display charge levels without relying on a single-chip microcontroller or software, reducing costs and static power consumption. The circuit structure is simple and clear, making it easy to use.

Claims

1. A lithium battery pack power display delay circuit, characterized in that: The device comprises a touch switch, a MOS tube Q6, a transistor Q5, a first group of voltage-dividing resistors, a diode D5, a capacitor C9, a resistor R3, and multiple display branches, wherein the multiple display branches are connected in parallel; the first group of voltage-dividing resistors comprises a resistor R1 and a resistor R2, wherein the resistors R1, R2, and the touch switch are connected in series between the positive and negative electrodes of the battery; one end of the resistor R2 is connected to one end of the capacitor C9, one end of the resistor R3, and the source electrode of the MOS tube Q6; the other end of the resistor R2 is connected to the positive electrode of the diode D5; the negative electrode of the diode D5, the other end of the capacitor C9, and the other end of the resistor R3 are all connected to the gate electrode of the MOS tube Q6; the drain electrode of the MOS tube Q6 is connected to the base electrode of the transistor Q5 via a current-limiting resistor R4; the emitter electrode of the transistor Q5 is connected to the positive electrode of the power supply; one end of the display branch is connected to the collector electrode of the transistor Q5, and the other end is connected to the negative electrode of the power supply; the display branch comprises a light-emitting diode and a voltage-dividing resistor, and the voltages divided by the voltage-dividing resistors of the multiple display branches are different.

2. The lithium battery pack power display delay circuit according to claim 1, characterized in that: The display branch also includes a driving chip, a current limiting resistor and a shunt resistor. The voltage dividing resistor is connected between the positive and negative poles of the power supply, and the divided voltage is connected to the driving chip. The output of the driving chip is connected to the shunt resistor and the current limiting resistor in sequence, and the light-emitting diode is connected in parallel with the shunt resistor.

3. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: There are three display branches, including a first display branch, a second display branch, and a third display branch. The voltages divided by the voltage-dividing resistors in the first display branch, the second display branch, and the third display branch decrease in sequence, and the output voltages of the driving chips in the first display branch, the second display branch, and the third display branch decrease in sequence.

4. The lithium battery pack power display delay circuit according to claim 3, characterized in that: The first display branch includes a second group of voltage-coupled resistors, the second display branch includes a third group of voltage-coupled resistors, and the third display branch includes a fourth group of voltage-coupled resistors. The second group of voltage-coupled resistors includes resistors R7 and R8, the third group of voltage-coupled resistors includes resistors R11 and R12, and the fourth group of voltage-coupled resistors includes resistors R14 and R15. Resistors R7, R11, and R14 are connected to the negative pole of the power supply, and resistors R8, R12, and R15 are connected to the collector of transistor Q5. The resistance values ​​of resistors R7, R11, and R14 decrease in sequence, and the resistance values ​​of resistors R8, R12, and R15 are the same.

5. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The resistance of resistor R3 is adjustable.

6. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The resistance values ​​of the resistors R7 and R8 are adjustable.

7. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The resistance values ​​of the resistor R11 and the resistor R12 are adjustable.

8. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The resistance values ​​of the resistor R14 and the resistor R15 are adjustable.

9. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The MOS transistor Q6 is an NMOS transistor.

10. The lithium battery pack power display delay circuit according to claim 1 or 2, characterized in that: The transistor Q5 is a PNP transistor.

Images