Positive / reverse step-up / step-down charge / discharge circuit and power tool

Abstract

The present application provides a forward / reverse step-up / step-down charging / discharging circuit and an electric tool, the forward / reverse step-up / step-down charging / discharging circuit including a battery, a forward / reverse step-up / step-down charging / discharging unit, and a first control unit, the battery is for storing electricity and supplying power to a load, the forward / reverse step-up / step-down charging / discharging unit is for charging / discharging the battery, the first control unit controls the forward / reverse step-up / step-down charging / discharging unit to step up or step down the power to supply power to the load, and controls the forward / reverse step-up / step-down charging / discharging unit to step up or step down the power from an external input voltage to charge the battery, the battery is connected to the forward / reverse step-up / step-down charging / discharging unit, and the forward / reverse step-up / step-down charging / discharging unit is connected to the first control unit. The forward / reverse step-up / step-down charging / discharging circuit and the electric tool provided by the embodiments of the present application have improved charging efficiency.

Description

[Technical field]

[0001] The present application relates to the technical field of power tools, and more particularly to a forward / reverse step-up / step-down charge / discharge circuit and a power tool. [Background technology]

[0002] Many conventional power tools available on the market only have a single discharge function, and when the lithium battery runs out of power, the lithium battery must be removed and charged with a charger, and after charging is complete, it must be installed in the power tool before it can be used. Summary of the Invention [Problem to be solved by the invention]

[0003] Since the lithium battery must be removed from the power tool, the charging efficiency is low. In order to solve the problem of having to remove the battery when charging, the embodiments of the present application provide a forward / reverse step-up / step-down charging / discharging circuit and a power tool that can at least partially solve the above problem. [Means for solving the problem]

[0004] In one aspect, the present application provides a forward / reverse step-up / step-down charge / discharge circuit, the circuit including: a battery; a forward / reverse step-up / step-down charge / discharge unit; and a first control unit; The battery is for storing electricity and supplying power to a load, the forward / reverse step-up / step-down charging / discharging unit is for charging / discharging the battery, the first control unit controls the forward / reverse step-up / step-down charging / discharging unit to supply power to a load by stepping up or stepping down, and controls the forward / reverse step-up / step-down charging / discharging unit to charge a battery by stepping up or stepping down an external input voltage; The battery is connected to the forward / reverse step-up / step-down charge / discharge unit, and the forward / reverse step-up / step-down charge / discharge unit is connected to the first control unit.

[0005] Furthermore, the positive and negative step-up and step-down charging and discharging unit includes a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, a first inductor, a first capacitor, and a second capacitor; the first switch transistor is connected in series with the second switch transistor; the third switch transistor is connected in series with the fourth switch transistor; a positive terminal of the battery is connected to a first terminal of the first switch transistor; a first end of the first switch transistor is connected to a first end of the first capacitor; a second end of the first capacitor is connected to a first end of the second capacitor; a second terminal of the second capacitor is connected to a first terminal of the third switch transistor; a second end of the first capacitor and a first end of the second capacitor are grounded; a first end of the first inductance is connected between the first switch transistor and the second switch transistor; a second end of the first inductance is connected between the third switch transistor and the fourth switch transistor; a second terminal of the second switch transistor and a second terminal of the fourth switch transistor are respectively connected to a negative terminal of the battery; The first control unit drives the first switch transistor, the second switch transistor, the third switch transistor and the fourth switch transistor to boost or lower the voltage of the battery to supply power to a load, and to boost or lower the voltage from an external input voltage to charge the battery.

[0006] Furthermore, the forward / reverse step-up / step-down charging / discharging circuit further includes a current regulating unit for regulating a current to protect the forward / reverse step-up / step-down charging / discharging circuit.

[0007] Furthermore, the positive and negative step-up / step-down charge / discharge circuit further includes at least one noise reduction unit connected in parallel to the first switch transistor, the second switch transistor, the third switch transistor, or the fourth switch transistor.

[0008] Furthermore, the forward / reverse step-up / step-down charging / discharging circuit further includes at least one filter capacitor each connected in parallel to the battery.

[0009] Furthermore, the forward and reverse buck-boost charging and discharging circuit further includes a second control unit connected to the first control unit, and the second control unit is for controlling the forward and reverse buck-boost charging and discharging unit so that the first control unit steps up or steps down the voltage to supply power to a load, and for controlling the forward and reverse buck-boost charging and discharging unit so that the first control unit steps up or steps down the voltage to charge a battery.

[0010] Furthermore, the forward and reverse buck-boost charging and discharging circuit further includes an input protection unit connected to the second control unit, the input protection unit being for providing overcurrent protection to the forward and reverse buck-boost charging and discharging circuit.

[0011] Further, the input protection unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor, a fifth capacitor, and a comparator; a first end of the first resistor is grounded, a second end of the first resistor is connected to a first end of the second resistor, and a second end of the first resistor is coupled to a negative circuit of the battery; a first end of the third capacitor is connected to a second end of the second resistor, and a second end of the third capacitor is grounded; a first end of the third resistor is connected to ground, a second end of the third resistor is connected to each of a first end of the fourth resistor and a first end of the fourth capacitor, and a second end of the fourth resistor and a second end of the fourth capacitor are connected to ground; a first input terminal of the comparator is connected to a second terminal of the second resistor, a second input terminal of the comparator is connected between the third resistor and the fourth resistor, and an output terminal of the comparator is connected to a first terminal of the sixth resistor; The first end of the fifth resistor is connected to the first end of the sixth resistor. 1 a second end of the fifth resistor connected to the First input a second end of the sixth resistor connected to a first end of the fifth capacitor, a second end of the fifth capacitor connected to ground, and a second end of the sixth resistor connected to the second control unit.

[0012] In addition, the input protection unit further includes a seventh resistor and a sixth capacitor; The first end of the sixth capacitor is connected to the first end of the fifth resistor. 2 ends a second end of the sixth capacitor connected to a first end of the seventh resistor, and a second end of the seventh resistor connected to a third end of the fifth resistor. 1 end was connected to.

[0013] Furthermore, the input protection unit includes a switch unit; the switch unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a triode, a Zener diode, a field effect transistor, and a common mode inductance; a first end of the eleventh resistor is connected to the second control unit, a second end of the eleventh resistor is connected to the base of the triode, and an emitter of the triode is grounded; a first end of the ninth resistor is connected to a second end of the eleventh resistor, and a second end of the ninth resistor is grounded; a first end of the tenth resistor is connected to the collector of the triode, and a second end of the tenth resistor is connected to each of a first end of the Zener diode, a first end of the twelfth resistor, and a source of the field effect transistor; a second end of the Zener diode and a second end of the twelfth resistor are respectively connected to a gate of the field effect transistor; The drain of the field effect transistor was connected to the common mode inductance, the gate of the field effect transistor was connected to the positive terminal of the battery, and the common mode inductance was connected to the negative terminal of the battery.

[0014] Furthermore, the forward and reverse step-up / step-down charging / discharging circuit further includes a step-down unit connected to the second control unit, the step-down unit being configured to step down the output voltage of the switch unit to a preset voltage.

[0015] Further, the step-down unit includes a fifth switch transistor, a sixth switch transistor, an eighth resistor, a second inductor, and a third control unit; a first terminal of the fifth switch transistor is connected to a positive terminal of the battery, and a second terminal of the fifth switch transistor is connected to a first terminal of the eighth resistor; a second end of the eighth resistor is connected to each of a first end of the sixth switch transistor and a first end of the second inductance, and a second end of the sixth switch transistor is grounded; a second end of the second inductance is connected to a step-down output end; The fifth switch transistor and the sixth switch transistor are respectively connected to the third control unit.

[0016] In addition, the step-down unit further includes at least one second noise reduction unit connected in parallel to the fifth switch transistor or the sixth switch transistor.

[0017] In another aspect, the present application proposes an electric power tool including a forward / reverse step-up / step-down charge / discharge circuit according to any one of the above embodiments.

[0018] The forward and reverse buck-boost charging and discharging circuit provided by the embodiments of the present application includes a battery, a forward and reverse buck-boost charging and discharging unit, and a first control unit, the battery is for storing electricity and supplying power to a load, the forward and reverse buck-boost charging and discharging unit is for charging and discharging the battery, the first control unit controls the forward and reverse buck-boost charging and discharging unit to supply power to the load by stepping up or stepping down, and controls the forward and reverse buck-boost charging and discharging unit to charge the battery by stepping up or stepping down an external input voltage, the battery is connected to the forward and reverse buck-boost charging and discharging unit, and the forward and reverse buck-boost charging and discharging unit is connected to the first control unit, thereby realizing a charging function without removing the battery and improving charging efficiency.

[0019] Brief Description of the Accompanying Drawings In order to more clearly describe the embodiments of the present invention or the technical solutions of the prior art, the following will briefly describe the accompanying drawings necessary for describing the embodiments or the prior art. The accompanying drawings described below are merely some embodiments of the present invention, and it is obvious to those skilled in the art that other accompanying drawings can be obtained based on these accompanying drawings without creative efforts.

[0020] Attached Drawings [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a second embodiment of the present invention. [Diagram 3] FIG. 3 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a third embodiment of the present invention. [Figure 4] FIG. 4 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a fourth embodiment of the present invention. [Diagram 5] FIG. 5 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a fifth embodiment of the present invention. [Figure 6]FIG. 6 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a sixth embodiment of the present invention. [Figure 7] FIG. 7 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a seventh embodiment of the present invention. [Figure 8] FIG. 8 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to an eighth embodiment of the present invention. [Figure 9] FIG. 9 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a ninth embodiment of the present invention. [Figure 10] FIG. 10 is a structural schematic diagram of an input protection unit provided in a tenth embodiment of the present application. [Figure 11] FIG. 11 is a structural schematic diagram of an input protection unit provided in an eleventh embodiment of the present application. [Figure 12] FIG. 12 is a structural schematic diagram of an input protection unit provided in a twelfth embodiment of the present application. [Figure 13] FIG. 13 is a structural schematic diagram of a forward / reverse step-up / step-down charge / discharge circuit according to a thirteenth embodiment of the present invention. [Figure 14] FIG. 14 is a structural schematic diagram of a voltage step-down unit provided in a fourteenth embodiment of the present invention. [Figure 15] FIG. 15 is a structural schematic diagram of a voltage step-down unit provided in a fifteenth embodiment of the present invention. [Figure 16] FIG. 16 is a structural schematic diagram of a voltage step-down unit provided in a sixteenth embodiment of the present invention. [Figure 17] FIG. 17 is a structural schematic diagram of a power tool according to a seventeenth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Specific embodiment In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will further describe the embodiments of the present application with reference to the accompanying drawings. Herein, the exemplary embodiments of the present application and the description thereof are for the purpose of explaining the present application, but are not intended to limit the present application. It should be noted that, unless there is a contradiction, the embodiments in the present application and the features described in the embodiments may be arbitrarily combined.

[0023] 1 is a structural schematic diagram of a forward / reverse step-up / step-down charging / discharging circuit provided in the first embodiment of the present application. As shown in FIG. 1, the forward / reverse step-up / step-down charging / discharging circuit provided in the first embodiment of the present application includes a battery 1, a forward / reverse step-up / step-down charging / discharging unit 2, and a first control unit 3, where: The battery 1 is for storing electricity and supplying it to a load. The forward / reverse step-up / step-down charging / discharging unit 2 is for charging / discharging the battery 1, the first control unit 2 controls the forward / reverse step-up / step-down charging / discharging unit 3 to supply power to the load by stepping up or stepping down, and controls the forward / reverse step-up / step-down charging / discharging unit 2 to charge the battery by stepping up or stepping down the external input voltage; The battery 1 is connected to a forward / reverse step-up / step-down charge / discharge unit 2 , which is connected to a first control unit 3 .

[0024] Specifically, the forward and reverse step-up and step-down charging and discharging circuit provided by the present application has two operating states: a forward power supply state and a reverse charging state. In the forward power supply state, if the voltage output from the output terminal needs to be lower than the DC voltage of the battery 1, the first control unit 3 controls the forward and reverse step-up and step-down charging and discharging unit 2 to drop the voltage supplied from the battery 1 and output it to the output terminal. If the voltage output from the output terminal needs to be higher than the DC voltage of the battery 1, the first control unit 2 controls the forward and reverse step-up and step-down charging and discharging unit 3 to increase the voltage supplied from the battery 1 and output it to the output terminal. In the reverse charging state, if the charging voltage for the battery 1 is lower than the voltage at the output terminal, the first control unit 2 controls the forward and reverse step-up and step-down charging and discharging unit 3 to drop the external input voltage supplied from the output terminal and output it to the battery 1, thereby performing step-down charging for the battery 1. If the charging voltage for the battery 1 is higher than the voltage at the output terminal, the first control unit 2 controls the forward / reverse step-up / step-down charging / discharging unit 3 to increase the voltage supplied from the battery 1 and output it to the battery 1, thereby boosting the charging of the battery 1 with the voltage at the output terminal.

[0025] The forward and reverse buck-boost charging and discharging circuit provided by the embodiments of the present application includes a battery, a forward and reverse buck-boost charging and discharging unit, and a first control unit, the battery is for storing electricity and supplying power to a load, the forward and reverse buck-boost charging and discharging unit is for charging and discharging the battery, the first control unit is for controlling the forward and reverse buck-boost charging and discharging unit to step up or step down to supply power to the load, and for charging the battery by controlling the forward and reverse buck-boost charging and discharging unit to step up or step down the voltage according to an external input voltage, and the battery is connected to the forward and reverse buck-boost charging and discharging unit, and the forward and reverse buck-boost charging and discharging unit is connected to the first control unit, so that the charging function can be performed without removing the battery, improving charging efficiency.

[0026] 2 is a structural schematic diagram of a positive / reverse step-up / step-down charging / discharging circuit provided in a second embodiment of the present application. As shown in FIG. 2, on the basis of the above embodiments, the positive / reverse step-up / step-down charging / discharging unit 2 provided in the embodiment of the present application further includes a first switch transistor Q1, a second switch transistor Q2, a third switch transistor Q3, a fourth switch transistor Q4, a first inductor L1, a first capacitor C1, and a second capacitor C2, where: The first switch transistor Q1 is connected in series to the second switch transistor Q2, the third switch transistor Q3 is connected in series to the fourth switch transistor Q4, the positive electrode of the battery 1 is connected to a first terminal of the first switch transistor Q1, the first terminal of the first switch transistor Q1 is connected to a first terminal of the first capacitor C1, the second terminal of the first capacitor C1 is connected to a first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to a first terminal of the third switch transistor Q3. The second end of the first capacitor C1 and the first end of the second capacitor C2 are grounded, the first end of the first inductance L1 is connected between the first switch transistor Q1 and the second switch transistor Q2, the second end of the first inductance L1 is connected between the third switch transistor Q3 and the fourth switch transistor Q4, the second end of the second switch transistor Q2 and the second end of the fourth switch transistor Q4 are respectively connected to the negative electrode of the battery 1, and the negative electrode of the battery 1 may be grounded. The Port1 terminal is the output terminal of the positive and reverse step-up / step-down charging / discharging unit 2.

[0027] The first control unit 3 is connected to each of the first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3, and the fourth switch transistor Q4, and drives the first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3, and the fourth switch transistor Q4 so as to boost or lower the voltage of the battery 1 to supply power to the load, and to boost or lower the voltage from an external input voltage to charge the battery 1. A lithium battery group may be used as the battery 1. The first control unit 3 may use a control chip of model number SC8815. The first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3, and the fourth switch transistor Q4 may use metal-oxide-semiconductor field-effect transistors (abbreviated as MOSFETs).

[0028] Specifically, the forward and reverse buck-boost charging and discharging circuit provided by the present application has two operating states: a forward power supply state and a reverse charging state. In the forward power supply state, if the voltage output from the output terminal needs to be lower than the voltage of the battery 1, the first switch transistor Q1 and the second switch transistor Q2 are driven by the first control unit 3 to be turned on as upper and lower arms, the first inductance L1 is set as a step-down inductance, and the third switch transistor Q3 is simultaneously turned on, so that a DC voltage lower than that of the battery 1 can be output from the output terminal. If the voltage output from the output terminal needs to be higher than the voltage of the battery 1, the first switch transistor Q1 is turned on, the first inductance L1 is set as a step-up inductance, and the third switch transistor Q3 and the fourth switch transistor Q4 are driven by the first control unit 3 to be turned on as upper and lower arms, so that a DC voltage higher than that of the battery 1 can be output from the output terminal. In the reverse charging state, if the reverse charging voltage for the battery 1 is lower than the voltage at the output terminal, the first switch transistor Q1 and the second switch transistor Q2 are driven by the first control unit 3 to be turned on as the upper and lower arms, the first inductance L1 is set as a step-down inductance, and the third switch transistor Q3 is simultaneously turned on, and step-down charging is performed on the battery 1 with the voltage at the output terminal. If the reverse charging voltage for the battery 1 is higher than the voltage at the output terminal, the first switch transistor Q1 is turned on, the first inductance L1 is set as a step-up inductance, and the third switch transistor Q3 and the fourth switch transistor Q4 are driven by the first control unit 3 to be turned on as the upper and lower arms, and step-up charging is performed on the battery 1 with the voltage at the output terminal. The first capacitor C1 and the second capacitor C2 perform the function of supplementing the operating frequency.

[0029] Based on the above embodiments, the forward / reverse step-up / step-down charging / discharging circuit provided by the present application further includes a current regulating unit for regulating and protecting the forward / reverse step-up / step-down charging / discharging circuit.

[0030] Specifically, the current regulating unit may be provided on a line connecting the battery 1 and the first switch transistor Q1, with a first terminal of the current regulating unit connected to the positive electrode of the battery 1 and a second terminal of the current regulating unit connected to a first terminal of the first switch transistor Q1.

[0031] Based on the above embodiments, the current regulating unit further includes at least one current regulating resistor, each of which has a first end connected to the positive electrode of the battery 1 and a second end connected to the first end of the first switch transistor Q1. The number of current regulating resistors may be set according to actual needs, but is not limited in the embodiments of the present application. The resistance value of each current regulating resistor may be set according to actual needs, but is not limited in the embodiments of the present application.

[0032] 3, the current regulating unit includes a first current regulating resistor R17 and a second current regulating resistor R18, and a first end of the first current regulating resistor R17 and a first end of the second current regulating resistor R18 are respectively connected to the positive electrode of the battery 1. A second end of the first current regulating resistor R17 and a second end of the second current regulating resistor R18 are respectively connected to a first end of the first switch transistor Q1.

[0033] 4 is a structural schematic diagram of a forward / reverse step-up / step-down charging / discharging circuit provided in a fourth embodiment of the present application. As shown in FIG. 4, based on the above embodiments, the forward / reverse step-up / step-down charging / discharging circuit provided in the embodiment of the present application further includes at least one noise reduction unit 22 connected in parallel to the first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3, or the fourth switch transistor Q4. The noise reduction unit 22 is for reducing the noise signal of the switch transistor.

[0034] Specifically, at least one noise reduction unit 22 may be connected in parallel to one or more of the first switch transistor Q1, the second switch transistor Q2, the third switch transistor Q3 and the fourth switch transistor Q4. The specific installation manner and quantity of the noise reduction unit 22 may be installed according to actual needs, and are not limited in the embodiments of the present application.

[0035] For example, Fig. 5 is a structural schematic diagram of a forward / reverse step-up / step-down charging / discharging circuit provided in the fifth embodiment of the present application. As shown in Fig. 5, based on the above embodiments, the forward / reverse step-up / step-down charging / discharging unit 2 further includes four noise reduction units, namely, a first noise reduction unit, a second noise reduction unit, a third noise reduction unit and a fourth noise reduction unit, where: The first noise reduction unit includes a thirteenth resistor R13 and a thirteenth capacitor C13, the thirteenth resistor R13 and the thirteenth capacitor C13 are connected in series and connected in parallel with the first switch transistor Q1, that is, a first end of the thirteenth resistor R13 is connected to a first end of the first switch transistor Q1, a first end of the thirteenth resistor R13 is connected to a first end of the thirteenth capacitor C13, and a second end of the thirteenth capacitor C13 is connected to the second end of the first switch transistor Q1.

[0036] The second noise reduction unit includes a fourteenth resistor R14 and a fourteenth capacitor C14, the fourteenth resistor R14 and the fourteenth capacitor C14 are connected in series and connected in parallel with the second switch transistor Q2, that is, a first end of the fourteenth resistor R14 is connected to a first end of the second switch transistor Q2, a first end of the fourteenth resistor R14 is connected to a first end of the fourteenth capacitor C14, and a second end of the fourteenth capacitor C14 is connected to a second end of the second switch transistor Q2.

[0037] The third noise reduction unit includes a fifteenth resistor R15 and a fifteenth capacitor C15, the fifteenth resistor R15 and the fifteenth capacitor C15 are connected in series and connected in parallel with the third switch transistor Q3, that is, a first end of the fifteenth resistor R15 is connected to a first end of the third switch transistor Q3, a first end of the fifteenth resistor R15 is connected to a first end of the fifteenth capacitor C15, and a second end of the fifteenth capacitor C15 is connected to a second end of the third switch transistor Q3.

[0038] The fourth noise reduction unit includes a sixteenth resistor R16 and a sixteenth capacitor C16, the sixteenth resistor R16 and the sixteenth capacitor C16 are connected in series and connected in parallel with the fourth switch transistor Q4, that is, a first end of the sixteenth resistor R16 is connected to a first end of the fourth switch transistor Q4, a first end of the sixteenth resistor R16 is connected to a first end of the sixteenth capacitor C16, and a second end of the sixteenth capacitor C16 is connected to a second end of the fourth switch transistor Q4.

[0039] The first noise reduction unit, the second noise reduction unit, the third noise reduction unit and the fourth noise reduction unit can perform the function of reducing noise signals of switch transistors.

[0040] FIG. 6 is a structural schematic diagram of a positive / reverse step-up / step-down charging / discharging circuit provided in a sixth embodiment of the present application. As shown in FIG. 6, based on the above embodiments, the positive / reverse step-up / step-down charging / discharging circuit provided in the embodiment of the present application further includes at least one filter capacitor C9, each of which is connected in parallel to the battery 1. The filter capacitor C9 functions as a filter. Here, the specific number of filter capacitors C9 may be installed according to actual needs, for example, four filter capacitors may be installed, but is not limited in the embodiment of the present application.

[0041] 7 is a structural schematic diagram of a positive / reverse buck-boost charging / discharging circuit according to a seventh embodiment of the present application. As shown in FIG. 7, the positive / reverse buck-boost charging / discharging circuit according to the present application includes a battery 1, three filter capacitors, a positive / reverse buck-boost charging / discharging unit 2, and a first control unit 3, where: The forward / reverse step-up / step-down charging / discharging unit 2 includes a first switch transistor Q1, a second switch transistor Q2, a third switch transistor Q3, a fourth switch transistor Q4, the first noise reduction unit, the second noise reduction unit, the third noise reduction unit, the fourth noise reduction unit, a first inductance L1, a first capacitor C1, a second capacitor C2, a first current regulating resistor R17, and a second current regulating resistor R18, the first switch transistor Q1 is connected in series to the second switch transistor Q2, the third switch transistor Q3 is connected in series to the fourth switch transistor Q4, a positive electrode of the battery 1 is connected to a first terminal of the first switch transistor Q1, A first terminal of the switch transistor Q1 is connected to a first terminal of the first capacitor C1, a second terminal of the first capacitor C1 is connected to a first terminal of the second capacitor C2, a second terminal of the second capacitor C2 is connected to a first terminal of the third switch transistor Q3, the second terminal of the first capacitor C1 and the first terminal of the second capacitor C2 are grounded, a first terminal of the first inductance L1 is connected between the first switch transistor Q1 and the second switch transistor Q2, a second terminal of the first inductance L1 is connected between the third switch transistor Q3 and the fourth switch transistor Q4, the second terminal of the second switch transistor Q2 and the second terminal of the fourth switch transistor Q4 are respectively connected to the negative terminal of the battery 1, and the negative terminal of the battery 1 is grounded.

[0042] The first noise reduction unit includes a thirteenth resistor R13 and a thirteenth capacitor C13, the thirteenth resistor R13 and the thirteenth capacitor C13 are connected in series and are connected in parallel with the first switch transistor Q1. The second noise reduction unit includes a fourteenth resistor R14 and a fourteenth capacitor C14, the fourteenth resistor R14 and the fourteenth capacitor C14 are connected in series and are connected in parallel with the second switch transistor Q2. The third noise reduction unit includes a fifteenth resistor R15 and a fifteenth capacitor C15, the fifteenth resistor R15 and the fifteenth capacitor C15 are connected in series and are connected in parallel with the third switch transistor Q3. The fourth noise reduction unit includes a sixteenth resistor R16 and a sixteenth capacitor C16, the sixteenth resistor R16 and the sixteenth capacitor C16 are connected in series and connected in parallel with the fourth switch transistor Q4.

[0043] A first end of the first current regulating resistor R17 and a first end of the second current regulating resistor R18 were each connected to the positive electrode of the battery 1. A second end of the first current regulating resistor R17 and a second end of the second current regulating resistor R18 were each connected to a first end of the first switch transistor Q1. A first filter capacitor C9, a second filter capacitor C10 and a third filter capacitor C11 were each connected in parallel to the battery cell 1.

[0044] 8 is a structural schematic diagram of a forward / reverse step-up / step-down charging / discharging circuit provided by the eighth embodiment of the present application. As shown in FIG. 8, the forward / reverse step-up / step-down charging / discharging circuit provided by the embodiment of the present application further includes a second control unit 814, and the forward / reverse step-up / step-down charging / discharging circuit 81 includes a battery 811, a forward / reverse step-up / step-down charging / discharging unit 812, and a first control unit 813, and the second control unit 814 is connected to the first control unit 813. The second control unit 814 is for controlling the forward / reverse step-up / step-down charging / discharging unit 812 so that the first control unit 813 steps up or steps down to supply power to the load, and controls the forward / reverse step-up / step-down charging / discharging unit 812 so that the battery 1 is charged by stepping up or stepping down the external input voltage.

[0045] For example, when the second control unit 814 detects that the voltage required for the output terminal of the forward / reverse step-up / step-down charging / discharging circuit is lower than the DC voltage from the battery 811, the second control unit 814 sends a first control signal to the first control unit 813. After receiving the first control signal, the first control unit 813 controls the forward / reverse step-up / step-down charging / discharging unit 812 to lower the voltage supplied from the battery 811 and output it to the output terminal. When the second control unit 814 detects that the voltage required for the output terminal of the forward / reverse step-up / step-down charging / discharging circuit is higher than the DC voltage from the battery 811, the second control unit 814 sends a second control signal to the first control unit 813. After receiving the second control signal, the first control unit 813 controls the forward / reverse step-up / step-down charging / discharging unit 812 to lower the voltage supplied from the battery 811 and output it to the output terminal. The second control unit 814 may be a control chip or may be selected according to actual needs, but is not limited in the embodiments of the present application.

[0046] 9 is a structural schematic diagram of a forward / reverse buck-boost charging / discharging circuit according to a ninth embodiment of the present application. As shown in FIG. 9, based on the above embodiments, the forward / reverse buck-boost charging / discharging circuit according to the embodiment of the present application further includes an input protection unit 815 connected to a second control unit 814, and the input protection unit 815 is for providing overcurrent protection to the forward / reverse buck-boost charging / discharging circuit 81.

[0047] 10 is a structural schematic diagram of an input protection unit provided in the tenth embodiment of the present application. As shown in FIG. 10, on the basis of the above embodiments, the input protection unit 815 further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a comparator U1, where: A first end of the first resistor R1 is grounded, a second end of the first resistor is connected to a first end of the second resistor R2, a second end of the first resistor is coupled to the negative circuit of the battery 1, a first end of the third capacitor C3 is connected to a second end of the second resistor R2, a second end of the third capacitor C3 is grounded, a first end of the third resistor R3 is grounded, a second end of the third resistor R3 is connected to each of a first end of a fourth resistor R4 and a first end of a fourth capacitor C4, a second end of the fourth resistor R4 and a second end of the fourth capacitor C4 are grounded, a first input end of the comparator U1 is connected to the second end of the second resistor R2, a second input end of the comparator U1 is connected between the third resistor R3 and the fourth resistor R4, an output end of the comparator U1 is connected to a first end of a sixth resistor R6, a first end of the fifth resistor R5 is connected to a third end of the sixth resistor R6, 1 The second end of the fifth resistor R5 is connected to the First input , a second end of the sixth resistor R6 is connected to a first end of the fifth capacitor C5, a second end of the fifth capacitor C5 is grounded, and a second end of the sixth resistor R6 is connected to the second control unit 814.

[0048] Specifically, the first end of the first resistor R1 is grounded, the second end of the first resistor R1 is coupled to the negative pole of the battery 1, and the overcurrent detection signal of the first resistor R1 is collected by the third resistor R3 and amplified by the comparator U1, and then passes through the sixth resistor R6 and flows into the detection pin of the second control unit 814. When the detection current obtained by the detection pin of the second control unit 814 exceeds the overcurrent threshold, the second control unit 814 sends an off signal to the first control unit 813 to stop the operation of the positive and reverse step-up and step-down charging and discharging circuit 81, thereby improving the safety of the circuit operation. Here, the third capacitor C4, the fourth capacitor C4, and the fifth capacitor C5 function as a filter to reduce interference. The fifth resistor R5 provides the number of amplification stages by the comparator U1. The sixth resistor R6 exerts the function of current regulation. Here, the first resistor R1 may be coupled to the negative pole circuit of the battery 1 by a common mode inductance. The overcurrent threshold may be set according to practical needs, but is not limited in the embodiment of the present application. The second end of the first resistor is the Port2 end. The second end of the sixth resistor is the Port3 end.

[0049] 11 is a structural schematic diagram of an input protection unit provided in an eleventh embodiment of the present application. As shown in FIG. 11, based on the above embodiments, the input protection unit 815 further includes a seventh resistor R7 and a sixth capacitor C6, where the first end of the sixth capacitor C6 is connected to the third end of the fifth resistor R5. 2 ends , a second end of the sixth capacitor C6 is connected to a first end of the seventh resistor R7, and a second end of the seventh resistor R7 is connected to a third end of the fifth resistor R5. 1 end The sixth capacitor C6 and the fifth resistor R5 serve to stabilize the comparator U1.

[0050] 12 is a structural schematic diagram of an input protection unit provided in a twelfth embodiment of the present application. As shown in FIG. 12, on the basis of the above-mentioned embodiments, the input protection unit 815 further includes a switch unit 8151, which includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a triode Q, a Zener diode D2, a field effect transistor T1, and a common mode inductance H, where: A first end of the eleventh resistor R11 is connected to the second control unit 814, a second end of the eleventh resistor R11 is connected to the base of the triode Q, and the emitter of the triode Q is grounded, a first end of the ninth resistor R9 is connected to the second end of the eleventh resistor R11, and the second end of the ninth resistor R9 is grounded, a first end of the tenth resistor R10 is connected to the collector of the triode Q, and a second end of the tenth resistor R10 is connected to each of a first end of a Zener diode D2, a first end of a twelfth resistor R12 and a source of a field effect transistor T1, and a second end of the Zener diode D2 and a second end of the twelfth resistor R12 are respectively connected to a gate of the field effect transistor T1, a drain of the field effect transistor T1 is connected to a common mode inductance H, a gate of the field effect transistor T1 is connected to a positive electrode of the battery 811, and the common mode inductance H is connected to a negative electrode of the battery 811.

[0051] As shown in FIG. 12, based on each of the above embodiments, further, the first resistor R1 is coupled to the negative circuit of the battery 811 by a common mode inductance H, a first end of the third resistor R3 is grounded, a first end of the sixth resistor R6 is connected to the output end of the comparator U1, and a second end of the sixth resistor R6 is connected to the detection pin of the second control unit 814. The first end of the eleventh resistor R11 is connected to the overcurrent control pin SW of the second control unit 814, the second end of the eleventh resistor R11 is connected to the base of the triode Q, the emitter of the triode Q is grounded, the first end of the ninth resistor R9 is connected to the second end of the eleventh resistor R11, the second end of the ninth resistor R9 is grounded, the first end of the tenth resistor is connected to the collector of the triode Q, the second end of the tenth resistor is connected to the first end of the Zener diode D2, the first end of the twelfth resistor R12 and the source of the field effect transistor T1, the second end of the Zener diode D2 and the second end of the twelfth resistor R12 are respectively connected to the gate of the field effect transistor T1, and the drain of the field effect transistor T1 is connected to the common mode inductance H. The Port4 terminal may be connected to the forward and reverse buck-boost charging and discharging unit 812.

[0052] When the input protection unit 815 determines that the negative electrode current of the battery 811 obtained by the detection pin exceeds the overcurrent threshold, the second control unit 814 outputs a control signal via the overcurrent control pin SW to turn off the triode Q, controls to turn off the field effect transistor T1, turns off the common mode inductance H, and cuts off the power supply circuit of the forward and reverse step-up / step-down charging / discharging circuit.

[0053] FIG. 13 is a structural schematic diagram of a forward / reverse step-up / step-down charging / discharging circuit provided by a thirteenth embodiment of the present application. As shown in FIG. 13, based on the above embodiments, the forward / reverse step-up / step-down charging / discharging circuit provided by the embodiment of the present application further includes a step-down unit 816 and a second control unit, the step-down unit 816 is connected to the second control unit 814, and the step-down unit 816 is for dropping the output voltage of the switch unit 8151 to a preset voltage. Here, the preset voltage may be set according to actual needs, but is not limited in the embodiment of the present application. The input terminal of the step-down unit 816 may be connected to the output terminal of the battery 811. The output terminal of the step-down unit 816 may be connected to a load to supply power to the load.

[0054] 14 is a structural schematic diagram of a step-down unit provided in the fourteenth embodiment of the present application. As shown in FIG. 14, the step-down unit 816 includes a fifth switch transistor Q5, a sixth switch transistor Q6, an eighth resistor R8, a second inductor L2, and a third control unit U2, where the first end of the fifth switch transistor Q5 is connected to the positive pole of the battery 811, the second end of the fifth switch transistor Q5 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the first end of the sixth switch transistor Q6 and the first end of the second inductor L2, respectively, the second end of the sixth switch transistor Q6 is grounded, the second end of the second inductor L2 is connected to the step-down output terminal, the fifth switch transistor Q5 and the sixth switch transistor Q6 are respectively connected to the third control unit U12, and the third control unit U2 is connected to the second control unit 814.

[0055] Specifically, the fifth switch transistor Q5 is an upper arm of the step-down circuit, the sixth switch transistor Q6 is a lower arm of the step-down circuit, the third control unit U2 provides a driving signal to the fifth switch transistor Q5 and the sixth switch transistor Q6, and the second inductance L2 is a reflux output inductance. The step-down unit 816 may step down the DC voltage supplied from the battery 1 and output it. The second control unit 814 transmits a step-down output trigger signal to the third control unit U2, so that the third control unit U2 controls the fifth switch transistor Q5 and the sixth switch transistor Q6 to output a preset voltage. The third control unit U2 may use a control chip of model number SC8002. The Port4 terminal is an input terminal of the step-down unit 816 and may be connected to the positive pole of the battery 811, and the Port5 terminal is an output terminal of the step-down unit 816 and may be externally connected to the input terminal of the load.

[0056] For example, the step-down unit 816 converts a DC voltage of 16V to 22V supplied and input from the battery 811 into a standard vehicle charging voltage of 12V / 10A and outputs it.

[0057] 15 is a structural schematic diagram of a step-down unit provided in a fifteenth embodiment of the present application. As shown in FIG. 15, based on the above embodiments, the step-down unit 816 further includes at least one second noise reduction unit 8161 connected in parallel with the fifth switch transistor Q5 or the sixth switch transistor Q6. The second noise reduction unit is for reducing the noise signal of the switch transistor.

[0058] Specifically, at least one second noise reduction unit 8161 may be connected in parallel to one or more of the fifth switch transistor Q5 or the sixth switch transistor Q6. The specific installation manner and quantity of the second noise reduction unit 8161 may be installed according to actual needs, and are not limited in the embodiments of the present application.

[0059] For example, Figure 16 is a structural schematic diagram of a step-down unit provided in the 16th embodiment of the present application. As shown in Figure 16, based on the above embodiments, the second noise reduction unit 8161 further includes a fifth noise reduction unit and a sixth noise reduction unit, where: The fifth noise reduction unit includes a 19th resistor R19 and a 12th capacitor C12, the 19th resistor R19 and the 12th capacitor C12 are connected in series and connected in parallel to the fifth switch transistor Q5, and the sixth noise reduction unit includes a 20th resistor R20 and a 13th capacitor C17, the 20th resistor R20 and the 13th capacitor C17 are connected in series and connected in parallel to the sixth switch transistor Q6. The fifth noise reduction unit and the sixth noise reduction unit perform the function of reducing the noise signal of the switch transistor.

[0060] An embodiment of the present application provides an electric power tool including the forward / reverse step-up / step-down charge / discharge circuit according to any one of the above embodiments. The electric power tool includes, but is not limited to, a lighter.

[0061] Fig. 17 is a structural schematic diagram of an electric power tool according to a seventeenth embodiment of the present application. As shown in Fig. 17, based on the above-mentioned embodiments, the electric power tool according to the seventeenth embodiment of the present application further includes a positive / reverse step-up / step-down charging / discharging circuit 81, a second control unit 814, an input protection unit 815, a step-down unit 816, and an instruction unit 82, where: The forward and reverse step-up and step-down charging and discharging circuit 81 includes a battery 811, a forward and reverse step-up and step-down charging and discharging unit 812, and a first control unit 813. The second control unit 814 is connected to each of the first control unit 813, the input protection unit 815, the step-down unit 816, and the instruction unit 82. The step-down unit 816 is connected to the battery 811 and is for reducing and outputting the voltage of the battery 811. The input protection unit 815 is connected to the battery 811 and is for providing overcurrent protection to the forward and reverse step-up and step-down charging and discharging circuit 81. The instruction unit 82 is for presenting an overcurrent in response to an instruction from the second control unit 814.

[0062] When the input protection unit 815 detects an overcurrent, the second control unit 814 can send an overcurrent indication signal to the indication unit 82, and the indication unit 82 can perform an overcurrent indication according to the overcurrent indication signal. For example, the indication unit 82 includes an LED indication lamp, and the indication unit 82 turns on the LED indication lamp when receiving the overcurrent indication signal.

[0063] The electric tool provided by the present application has advantages such as small volume, large power and light weight, and can realize positive and reverse step-up and step-down charging and discharging of a rechargeable battery. The battery provides energy to a load, and after the battery runs out of power, the battery may be fully charged using a charging interface such as a USB-C port. In addition, an input protection unit is installed to collect the current flowing into the negative electrode of the battery, and when the second control unit determines that an overcurrent has occurred, it turns off the enable pin signal from the first control unit to stop the operation of the positive and reverse step-up and step-down charging and discharging circuit, and sends an overcurrent indication signal to the indication unit to cause the indication unit to perform an overcurrent indication. This improves the safety of the use of the electric tool. In addition, the step-down unit can provide a power supply function like an in-vehicle charging output port, and can supply power to an electric appliance with a full power of 120W and DC 12V.

[0064] In the present description, the reference terms "one embodiment," "one specific embodiment," "some embodiments," "for example," "example," "specific examples," or "some examples" refer to specific components, structures, materials, or features described in combination with the embodiment or example being included in at least one embodiment or example of the present application. In the present description, the exemplary expressions for the above terms do not necessarily refer to the same embodiment or example. Moreover, specific components, structures, materials, or features described may be combined in any suitable manner in any one or more embodiments or examples.

[0065] The specific embodiments described above further explain the objectives, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application, and is not intended to limit the scope of protection of the present application. Any amendments, equivalent replacements, improvements, etc. made according to the spirit and principles of the present application are within the scope of protection of the present application.

Claims

1. The battery includes a forward / reverse step-up / step-down charge / discharge unit, and a first control unit; The battery is for storing electricity and supplying power to a load, the forward / reverse step-up / step-down charging / discharging unit is for charging / discharging the battery, the first control unit controls the forward / reverse step-up / step-down charging / discharging unit to supply power to a load by stepping up or stepping down, and controls the forward / reverse step-up / step-down charging / discharging unit to charge the battery by stepping up or stepping down an external input voltage; the battery is connected to the positive / reverse step-up / step-down charging / discharging unit, and the positive / reverse step-up / step-down charging / discharging unit is connected to the first control unit; further comprising a second control unit connected to the first control unit; The second control unit is The first control unit controls the forward / reverse step-up / step-down charging / discharging unit to supply power to a load by stepping up or stepping down the voltage, and controls the forward / reverse step-up / step-down charging / discharging unit to charge a battery by stepping up or stepping down an external input voltage. This is for the purpose of an input protection unit connected to the second control unit, the input protection unit providing overcurrent protection; the input protection unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor, a fifth capacitor, and a comparator; a first end of the first resistor is grounded, a second end of the first resistor is connected to a first end of the second resistor, and a second end of the first resistor is coupled to a negative circuit of the battery; a first end of the third capacitor is connected to a second end of the second resistor, and a second end of the third capacitor is grounded; a first end of the third resistor is grounded, and a second end of the third resistor is connected to each of a first end of the fourth resistor and a first end of the fourth capacitor; a second end of the fourth resistor and a second end of the fourth capacitor are grounded; a first input terminal of the comparator is connected to the second terminal of the second resistor, a second input terminal of the comparator is connected between the third resistor and the fourth resistor, and an output terminal of the comparator is connected to the first terminal of the sixth resistor; a first end of the fifth resistor is connected to a first end of the sixth resistor, and a second end of the fifth resistor is connected to a first input end of the comparator; a second end of the sixth resistor is connected to a first end of the fifth capacitor, a second end of the fifth capacitor is grounded, and a second end of the sixth resistor is connected to the second control unit; A forward / reverse step-up / step-down charge / discharge circuit.

2. The positive and negative step-up and step-down charging and discharging unit includes a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, a first inductor, a first capacitor, and a second capacitor; the first switch transistor is connected in series with the second switch transistor; the third switch transistor is connected in series with the fourth switch transistor; a positive terminal of the battery is connected to a first terminal of the first switch transistor; a first end of the first switch transistor is connected to a first end of the first capacitor; a second end of the first capacitor connected to a first end of the second capacitor; a second end of the second capacitor is connected to a first end of the third switch transistor; a second end of the first capacitor and a first end of the second capacitor are grounded; a first end of the first inductance is connected between the first switch transistor and the second switch transistor; a second end of the first inductance is connected between the third switch transistor and the fourth switch transistor; a second terminal of the second switch transistor and a second terminal of the fourth switch transistor are respectively connected to a negative terminal of the battery; The first control unit drives the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor so as to boost or drop the voltage of the battery to supply power to a load, and to boost or drop the voltage from an external input voltage to charge the battery.

2. The forward / reverse step-up / step-down charge / discharge circuit according to claim 1.

3. 3. The forward / reverse buck-boost charging / discharging circuit according to claim 2, further comprising a current regulating unit for regulating a current for protection of the forward / reverse buck-boost charging / discharging circuit.

4. at least one noise reduction unit connected in parallel to the first switch transistor, the second switch transistor, the third switch transistor, or the fourth switch transistor; 3. The forward / reverse step-up / step-down charge / discharge circuit according to claim 2.

5. 2. The forward / reverse buck-boost charging / discharging circuit of claim 1, further comprising at least one filter capacitor each connected in parallel with said battery.

6. the input protection unit further includes a seventh resistor and a sixth capacitor; a first end of the sixth capacitor is connected to a second end of the fifth resistor, a second end of the sixth capacitor is connected to a first end of the seventh resistor, and a second end of the seventh resistor is connected to a first end of the fifth resistor; 2. The forward / reverse step-up / step-down charge / discharge circuit according to claim 1.

7. The battery includes a forward / reverse step-up / step-down charge / discharge unit, and a first control unit; The battery is for storing electricity and supplying power to a load, the forward / reverse step-up / step-down charging / discharging unit is for charging / discharging the battery, the first control unit controls the forward / reverse step-up / step-down charging / discharging unit to supply power to a load by stepping up or stepping down, and controls the forward / reverse step-up / step-down charging / discharging unit to charge the battery by stepping up or stepping down an external input voltage; the battery is connected to the positive / reverse step-up / step-down charging / discharging unit, and the positive / reverse step-up / step-down charging / discharging unit is connected to the first control unit; further comprising a second control unit connected to the first control unit; The second control unit is The first control unit controls the forward / reverse step-up / step-down charging / discharging unit to supply power to a load by stepping up or stepping down the voltage, and controls the forward / reverse step-up / step-down charging / discharging unit to charge a battery by stepping up or stepping down an external input voltage. This is for the purpose of an input protection unit connected to the second control unit, the input protection unit providing overcurrent protection; the input protection unit includes a switch unit; the switch unit includes a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a triode, a Zener diode, a field effect transistor, and a common mode inductance; a first end of the eleventh resistor is connected to the second control unit, a second end of the eleventh resistor is connected to the base of the triode, and an emitter of the triode is grounded; a first end of the ninth resistor is connected to a second end of the eleventh resistor, and a second end of the ninth resistor is grounded; a first end of the tenth resistor is connected to the collector of the triode, and a second end of the tenth resistor is connected to each of a first end of the Zener diode, a first end of the twelfth resistor, and a source of the field effect transistor; a second end of the Zener diode and a second end of the twelfth resistor are respectively connected to a gate of the field effect transistor; The drain of the field effect transistor is connected to the common mode inductance, the gate of the field effect transistor is connected to the positive terminal of the battery, and the common mode inductance is connected to the negative terminal of the battery. A forward / reverse step-up / step-down charge / discharge circuit.

8. The positive and negative step-up and step-down charging and discharging unit includes a first switch transistor, a second switch transistor, a third switch transistor, a fourth switch transistor, a first inductor, a first capacitor, and a second capacitor; the first switch transistor is connected in series with the second switch transistor; the third switch transistor is connected in series with the fourth switch transistor; a positive terminal of the battery is connected to a first terminal of the first switch transistor; a first end of the first switch transistor is connected to a first end of the first capacitor; a second end of the first capacitor connected to a first end of the second capacitor; a second end of the second capacitor is connected to a first end of the third switch transistor; a second end of the first capacitor and a first end of the second capacitor are grounded; a first end of the first inductance is connected between the first switch transistor and the second switch transistor; a second end of the first inductance is connected between the third switch transistor and the fourth switch transistor; a second terminal of the second switch transistor and a second terminal of the fourth switch transistor are respectively connected to a negative terminal of the battery; The first control unit drives the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor so as to boost or drop the voltage of the battery to supply power to a load, and to boost or drop the voltage from an external input voltage to charge the battery.

8. The positive / reverse step-up / step-down charge / discharge circuit according to claim 7.

9. 9. The forward / reverse buck-boost charging / discharging circuit according to claim 8, further comprising a current regulating unit for regulating a current for protection of the forward / reverse buck-boost charging / discharging circuit.

10. at least one noise reduction unit connected in parallel to the first switch transistor, the second switch transistor, the third switch transistor, or the fourth switch transistor; 9. The positive / reverse step-up / step-down charge / discharge circuit according to claim 8.

11. 8. The forward / reverse buck-boost charging / discharging circuit of claim 7, further comprising at least one filter capacitor each connected in parallel with said battery.

12. a step-down unit connected to the second control unit; 8. The forward / reverse step-up / step-down charging / discharging circuit according to claim 7, wherein the step-down unit is adapted to step-down the output voltage of the switch unit to a preset voltage.

13. the step-down unit includes a fifth switch transistor, a sixth switch transistor, an eighth resistor, a second inductor, and a third control unit; a first terminal of the fifth switch transistor is connected to a positive terminal of the battery, and a second terminal of the fifth switch transistor is connected to a first terminal of the eighth resistor; a second end of the eighth resistor is connected to each of a first end of the sixth switch transistor and a first end of the second inductance, and a second end of the sixth switch transistor is grounded; a second end of the second inductance is connected to a step-down output end; the fifth switch transistor and the sixth switch transistor are each connected to the third control unit; 13. The forward / reverse step-up / step-down charge / discharge circuit according to claim 12.

14. the step-down unit further includes at least one second noise reduction unit connected in parallel to the fifth switch transistor or the sixth switch transistor; 14. The forward / reverse step-up / step-down charge / discharge circuit according to claim 13.

15. An electric power tool comprising the forward / reverse step-up / step-down charge / discharge circuit according to any one of claims 1 to 14.

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