Control circuit board of electric tool

Abstract

The utility model relates to an electric tool control circuit board which comprises a circuit board, a control circuit is arranged on the circuit board, one end of the control circuit is electrically connected with a plug terminal, the other end of the control circuit is electrically connected with a battery pack, the battery pack is provided with a battery peripheral circuit, and a positive electrode of the battery pack is electrically connected with an input end of a first electronic switch circuit. The control end of the first electronic switch circuit is electrically connected with the plug terminal, the output end of the first electronic switch circuit is electrically connected with the input end of the second electronic switch circuit, the control end of the second electronic switch circuit is electrically connected with one end of the mechanical switch, and the output end of the second electronic switch circuit is electrically connected with the power supply output circuit. The power supply output circuit is electrically connected with the power end of the electric tool. The scheme has the advantages of simple circuit, low cost, multiple purposes, high working efficiency and convenience in use for users. The principle of the scheme can be universally applied to portable electric tool products of various models and specifications.

Description

TECHNICAL FIELD

[0001] The utility model relates to electric tool product technical field especially, relates to a kind of electric tool control circuit board. BACKGROUND

[0002] Hand-held electric tool is a kind of portable electric tool, usually using battery or other movable power supply to provide power, designed as hand-held operation, suitable for various different applications and working environment. Common portable electric tools include electric drill, electric screwdriver, electric tool set etc. Portable electric tool has the advantages of small size, light weight, convenient to carry, but the existing portable electric tool has the defect that the tool cannot be used during charging of lithium battery.

[0003] In order to overcome the above-mentioned shortcomings, the present application provides an electric tool control circuit board. INVENTION CONTENTS

[0004] The purpose of the present application is to solve the problem of existing portable electric tools that cannot be used during charging of lithium battery. The specific solution is as follows:

[0005] An electric tool control circuit board, comprising a circuit board, a control circuit is provided on the circuit board, one end of the control circuit is electrically connected with a plug-in terminal, the other end of the control circuit is electrically connected with a battery pack, the battery pack is provided with a battery peripheral circuit, the positive electrode of the battery pack is electrically connected with the input end of a first electronic switch circuit, the control end of the first electronic switch circuit is electrically connected with the plug-in terminal, the output end of the first electronic switch circuit is electrically connected with the input end of a second electronic switch circuit, the control end of the second electronic switch circuit is electrically connected with one end of a mechanical switch, the output end of the second electronic switch circuit is electrically connected with a power supply output circuit, and the power supply output circuit is electrically connected with the power supply end of the electric tool.

[0006] Further, the control circuit includes a control IC, the BAT pin of the control IC is electrically connected with the positive electrode of an electrolytic capacitor C1, the negative electrode of the electrolytic capacitor C1 is grounded, the PROG pin of the control IC is electrically connected with one end of a resistor R1, the other end of the resistor R1 is grounded, the power supply end of the control IC is electrically connected with the plug-in terminal, the GND pin of the control IC is grounded, the BAT pin of the control IC is electrically connected with the positive electrode of the battery pack, and the negative electrode of the battery pack is grounded.

[0007] Further, the battery peripheral circuit includes one end of a resistor R2 electrically connected with the positive electrode of the battery pack, the other end of R2 is electrically connected with one end of a resistor R3, the other end of R3 is grounded, and the common end of resistors R2 and R3 is electrically connected with the BATADC I / O pin of the control chip.

[0008] Further, the first electronic switch circuit comprises a MOS tube Q1, the drain D of the MOS tube Q1 is an input end of the first electronic switch circuit, the gate G of the MOS tube Q1 is electrically connected with one end of a resistor R4 and the anode of a diode D1, the other end of the resistor R4 is grounded, the cathode of the diode D1 is electrically connected with the source S of the MOS tube Q1, the gate G of the MOS tube Q1 is electrically connected with a plug terminal and is a control end of the first electronic switch circuit, and the source S of the MOS tube Q1 is an output end of the first electronic switch circuit.

[0009] Further, the second electronic switch circuit comprises a MOS tube Q2, the source S of the MOS tube Q2 is an input end of the second electronic switch circuit, the source S of the MOS tube Q2 is electrically connected with one end of a resistor R5, the other end of the resistor R5 is electrically connected with the gate G of the MOS tube Q2, the gate G of the MOS tube Q2 is a control end of the second electronic switch circuit, the drain D of the MOS tube Q2 is an output end of the second electronic switch circuit, and one end of a mechanical switch S1 is electrically connected with the gate G of the MOS tube Q2, and the other end of the mechanical switch S1 is grounded.

[0010] Further, the power supply output circuit comprises a power supply output end VOUT, the power supply output end VOUT is electrically connected with the positive electrode of an electrolytic capacitor C2 and one end of a capacitor C3, the negative electrode of the electrolytic capacitor C2 and the other end of the capacitor C3 are grounded.

[0011] Further, the MOS tube Q1 is a P-channel MOS tube.

[0012] Further, the MOS tube Q2 is a P-channel MOS tube.

[0013] Further, the control IC is a TP4056.

[0014] Further, the mechanical switch is a power button switch on the electric tool.

[0015] The scheme has the following beneficial effects:

[0016] The circuit of the scheme is simple, only a control IC, two MOS tubes, a diode, several resistors, two electrolytic capacitors, a capacitor and a mechanical switch are needed, and the three functions of power supply of a lithium battery to an electric tool, charging of the lithium battery and use of the electric tool while charging the lithium battery can be realized simultaneously by additionally arranging an MCU chip, so that the scheme has the multiple advantages of simple circuit, low cost, multiple use, high working efficiency and convenience for users. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a structural view of the electric tool control circuit board of the utility model;

[0018] Figure 2 This is a circuit diagram of a power tool control circuit board according to the present invention.

[0019] Explanation of reference numerals in the attached figures:

[0020] 10-Control circuit, 20-Battery pack, 30-Battery peripheral circuit, 40-First electronic switch circuit, 50-Second electronic switch circuit, 60-Mechanical switch, 70-Power supply output circuit, 80-Plug-in terminal, 90-Power tool, Circuit board-100. Detailed Implementation

[0021] The embodiments of this utility model are described in detail below with reference to the accompanying drawings. The embodiments are given for illustrative purposes only and should not be construed as limiting the utility model. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of this utility model, because many changes can be made to this utility model without departing from the spirit and scope of this utility model.

[0022] like Figure 1 , 2 As shown, a power tool control circuit board includes a circuit board 100. A control circuit 10 is provided on the circuit board 100. One end of the control circuit 10 is electrically connected to a plug-in terminal 80, and the other end is electrically connected to a battery pack 20. The battery pack 20 has a battery peripheral circuit 30. The positive electrode of the battery pack 20 is electrically connected to the input terminal of a first electronic switch circuit 40. The control terminal of the first electronic switch circuit 40 is electrically connected to the plug-in terminal 80. The output terminal of the first electronic switch circuit 40 is electrically connected to the input terminal of a second electronic switch circuit 50. The control terminal of the second electronic switch circuit 50 is electrically connected to one end of a mechanical switch 60. The output terminal of the second electronic switch circuit 50 is electrically connected to a power supply output circuit 70, which is electrically connected to the power supply terminal of the power tool 90. The battery pack 20 is a lithium battery, and the parameters of the lithium battery are selected according to the needs of the power tool. The circuit board 100 is housed inside the casing of the power tool 90 (not shown in the figure), offering the advantage of a compact design. The plug-in terminal 80 is a charging interface.

[0023] Specifically, the control circuit 10 includes a control IC (corresponding to...) Figure 2 In the charger IC, the BAT pin of the control IC is electrically connected to the positive terminal of electrolytic capacitor C1, and the negative terminal of electrolytic capacitor C1 is grounded. The PROG pin of the control IC is electrically connected to one end of resistor R1, and the other end of resistor R1 is grounded. The power supply terminal of the control IC is connected to terminal 80 (corresponding to...). Figure 2 The Charger is electrically connected, the GND pin of the control IC is grounded, and the BAT pin of the control IC is connected to the battery pack 20 (corresponding to...). Figure 2The positive electrode of the battery pack 20 is electrically connected to the positive electrode of the battery, and the negative electrode of the battery pack 20 is grounded.

[0024] Specifically, the battery peripheral circuit 30 includes one end of a resistor R2 electrically connected to the positive electrode of the battery pack 20, the other end of the resistor R2 electrically connected to one end of a resistor R3, the other end of the resistor R3 grounded, and the common end of the resistors R2 and R3 electrically connected to the BAT ADC I / O pin of the control chip (not shown in the figure) mounted on the circuit board 100. The control chip is a common MCU chip, which functions to monitor the voltage of the lithium battery and ensure that the minimum and maximum values of the lithium battery voltage are within a safe range. The specific model and working principle of the control chip are not described in detail here.

[0025] Specifically, the first electronic switch circuit 40 includes a MOS tube Q1, the drain D of the MOS tube Q1 being the input end of the first electronic switch circuit 40, the gate G of the MOS tube Q1 being electrically connected to one end of a resistor R4 and the anode of a diode D1, the other end of the resistor R4 being grounded, the cathode of the diode D1 being electrically connected to the source S of the MOS tube Q1, and the gate G of the MOS tube Q1 being the control end and the plug-in terminal 80 (corresponding to the Figure 2 the Charger) of the first electronic switch circuit 40, and the source S of the MOS tube Q1 being the output end of the first electronic switch circuit 40.

[0026] Specifically, the second electronic switch circuit 50 includes a MOS tube Q2, the source S of the MOS tube Q2 being the input end of the second electronic switch circuit 50, the source S of the MOS tube Q2 being electrically connected to one end of a resistor R5, the other end of the resistor R5 being electrically connected to the gate G of the MOS tube Q2, the gate G of the MOS tube Q2 being the control end of the second electronic switch circuit 50, the drain D of the MOS tube Q2 being the output end of the second electronic switch circuit 50, one end of a mechanical switch (also referred to as 60) S1 being electrically connected to the gate G of the MOS tube Q2, and the other end of the mechanical switch S1 being grounded.

[0027] Specifically, the power supply output circuit 70 includes a power supply output end VOUT, the power supply output end VOUT being electrically connected to the positive electrode of a capacitor C2 and one end of a capacitor C3, the negative electrode of the capacitor C2 and the other end of the capacitor C3 being grounded. The power supply output end VOUT is electrically connected to the power supply end of the electric tool 90.

[0028] Specifically, the MOS tube Q1 is a P-channel MOS tube, the parameters of which are configured according to the parameters of the lithium battery.

[0029] Specifically, the MOS tube Q2 is a P-channel MOS tube, the parameters of which are configured according to the parameters of the lithium battery.

[0030] Optionally, the model of the control IC is TP4056, or other alternative models can be used.

[0031] Specifically, the mechanical switch (i.e., 60) S1 is the power button switch on the power tool.

[0032] The working principle of the charging circuit in this solution is briefly described as follows:

[0033] (1) When the power tool is not plugged into terminal 80, the battery pack 20 (e.g., lithium battery) discharges, and the body diode of MOSFET Q1 (attached) Figure 2 The circuit (distributed between the drain D and source S) transfers the battery voltage 4.2V of the battery pack 20 to the source S of MOSFET Q1. Since the gate G of MOSFET Q1 is not connected to the terminal 80, the voltage of the gate G is 0V. Since the Vgs (gate-source voltage difference) of MOSFET Q1 = 0 - 4.2 - 0.7 (voltage drop of diode D1) = -3.5V, the conduction condition of MOSFET Q1 is met. MOSFET Q1 is turned on, and the voltage at the source S of MOSFET Q1, which is also the source S of MOSFET Q2, is 4.2V. If the mechanical switch S1 of the power tool is not pressed (i.e., not closed), the resistor R5 transfers the high voltage to the gate G of MOSFET Q2. MOSFET Q2 is not turned on, the power output terminal VOUT is 0V, and the power tool 90 does not work. When the mechanical switch S1 of the power tool is pressed (i.e. closed), the mechanical switch S1 grounds the gate G of the MOSFET Q2, which is 0V. At this time, the Vgs of the MOSFET Q2 is -4.2V, and the MOSFET Q2 meets the conduction condition. After conduction, VOUT is 4.2V, and the power tool 90 is powered on and works.

[0034] (2) When the charger is plugged into the power tool's connector 80, the control IC charges the battery pack 20. Simultaneously, connector 80 causes the gate G of MOSFET Q1 to have a voltage of 5V, and through diode D1, the source S voltage of MOSFET Q1 becomes 5V - 0.3V = 4.7V. Since the Vgs of MOSFET Q1 is 5V - 4.7V > 0V, MOSFET Q1 is not conducting. At this time, the drain D and source S of MOSFET Q1 are disconnected. Therefore, if the power tool's mechanical switch S1 is not pressed (i.e., not closed), the resistance R... 5. The high voltage is transferred to the gate G of MOSFET Q2. MOSFET Q2 is not turned on, and the power supply output VOUT is 0V. The power tool 90 does not work. If the mechanical switch S1 of the power tool is pressed (i.e. closed), the mechanical switch S1 grounds the gate G of MOSFET Q2, which is 0V. At this time, the Vgs of MOSFET Q2 is -4.7V. MOSFET Q2 meets the conduction condition. After conduction, VOUT is 4.7V, and the power tool 90 is powered on and works. This realizes the unique function of this solution: charging the lithium battery while continuing to use the power tool.

[0035] The MCU chip monitors the voltage of the battery pack 20, and prompts charging when the voltage is lower than the charging voltage value, and prompts charging completion when the voltage reaches the full voltage value, which belongs to the prior art and will not be described here.

[0036] The present scheme has the following beneficial effects:

[0037] The circuit of the present scheme is simple, only one control IC, two MOS tubes, one diode, several resistors, two electrolytic capacitors, one capacitor and a mechanical switch are needed, and a MCU chip is further needed to simultaneously realize the three functions of power supply of the lithium battery to the electric tool, charging of the lithium battery and use of the electric tool during charging of the lithium battery, and the present scheme has multiple advantages of simple circuit, low cost, multiple use, high work efficiency and convenience for users.

[0038] The above embodiment is the preferred embodiment of the present application, but the embodiment of the present application is not limited by the above embodiment, and any change, modification, substitution, combination, simplification made without departing from the spirit and principle of the present application should be an equivalent replacement mode, and all are included in the protection scope of the present application.

Claims

1. A power tool control circuit board comprising a circuit board, characterized by: The circuit board is provided with a control circuit, one end of the control circuit is electrically connected with the plug-in terminal, the other end of the control circuit is electrically connected with the battery pack, the battery pack is provided with a battery peripheral circuit, the positive electrode of the battery pack is electrically connected with the input end of the first electronic switch circuit, the control end of the first electronic switch circuit is electrically connected with the plug-in terminal, the output end of the first electronic switch circuit is electrically connected with the input end of the second electronic switch circuit, the control end of the second electronic switch circuit is electrically connected with one end of the mechanical switch, the output end of the second electronic switch circuit is electrically connected with the power supply output circuit, and the power supply output circuit is electrically connected with the power supply end of the electric tool.

2. The control circuit board for a power tool according to claim 1, wherein: The control circuit comprises a control IC, the BAT pin of the control IC is electrically connected with the positive electrode of the electrolytic capacitor C1, the negative electrode of the electrolytic capacitor C1 is grounded, the PROG pin of the control IC is electrically connected with one end of the resistor R1, the other end of the resistor R1 is grounded, the power supply end of the control IC is electrically connected with the plug-in terminal, the GND pin of the control IC is grounded, and the BAT pin of the control IC is electrically connected with the positive electrode of the battery pack.

3. The control circuit board for a power tool of claim 1, wherein: The battery peripheral circuit comprises one end of the resistor R2 electrically connected with the positive electrode of the battery pack, the other end of the resistor R2 is electrically connected with one end of the resistor R3, the other end of the resistor R3 is grounded, and the common end of the resistors R2 and R3 is electrically connected with the BAT ADC I / O pin of the control chip.

4. The control circuit board for a power tool of claim 1, wherein: The first electronic switch circuit comprises a MOS tube Q1, the drain D of the MOS tube Q1 is the input end of the first electronic switch circuit, the gate G of the MOS tube Q1 is electrically connected with one end of the resistor R4 and the positive electrode of the diode D1, the other end of the resistor R4 is grounded, the negative electrode of the diode D1 is electrically connected with the source S of the MOS tube Q1, the gate G of the MOS tube Q1 is the control end of the first electronic switch circuit and is electrically connected with the plug-in terminal, and the source S of the MOS tube Q1 is the output end of the first electronic switch circuit.

5. The control circuit board for a power tool of claim 1, wherein: The second electronic switch circuit comprises a MOS tube Q2, the source S of the MOS tube Q2 is the input end of the second electronic switch circuit, the source S of the MOS tube Q2 is electrically connected with one end of the resistor R5, the other end of the resistor R5 is electrically connected with the gate G of the MOS tube Q2, the gate G of the MOS tube Q2 is the control end of the second electronic switch circuit, the drain D of the MOS tube Q2 is the output end of the second electronic switch circuit, one end of the mechanical switch S1 is electrically connected with the gate G of the MOS tube Q2, and the other end of the mechanical switch S1 is grounded.

6. The control circuit board for a power tool of claim 1, wherein: The power supply output circuit comprises a power supply output end VOUT, the power supply output end VOUT is electrically connected with the positive electrode of the electrolytic capacitor C2 and one end of the capacitor C3, and the negative electrode of the electrolytic capacitor C2 and the other end of the capacitor C3 are grounded.

7. The control circuit board for a power tool of claim 4, wherein: The MOS tube Q1 is a P-channel MOS tube.

8. The control circuit board for a power tool of claim 5, wherein: The MOS tube Q2 is a P-channel MOS tube.

9. The control circuit board for a power tool of claim 2, wherein: The model of the control IC is TP4056.

10. The control circuit board for a power tool of claim 1, wherein: The mechanical switch is a power button switch on the electric tool.

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