CN218733214U - Electric rotary tool protection circuit and electric rotary tool - Google Patents

Abstract

The utility model provides an electric rotary tool protection circuit and electric rotary tool, electric rotary tool protection circuit includes: the protection circuit comprises a first communication circuit board, a driving circuit, a power supply circuit and a power-on detection circuit; the first connecting end of the first communication circuit board is electrically connected with a driving circuit, and the driving circuit is electrically connected with a motor; the power supply circuit comprises a power supply and a switch, one end of the switch is electrically connected with the power supply, and the other end of the switch is electrically connected with the second connecting end of the first communication circuit board; and the third connecting end of the first communication circuit board is connected with the power-on detection circuit and used for transmitting the level signal of the third connecting end to the first communication circuit board. Connect power and first communication circuit board through the switch, go up the level signal of electric detection circuitry transmission third link, first communication circuit board receives low level signal then the closed back motor operation of switch, receives high level signal then the motor does not operate, prevents that power access back motor from operating immediately and causing the injury for the user.

Description

Electric rotary tool protection circuit and electric rotary tool

Technical Field

The utility model relates to an electric tool technical field especially relates to an electric rotary tool protection circuit and electric rotary tool.

Background

With the development of light weight and miniaturization of electric tools, more and more electric tools are going into people's daily life. However, in the case of using an electric power tool, particularly an electric rotary tool such as an electric angle grinder or an electric saw, whether a professional operator or a non-professional operator, there are cases where the power supply is directly cut off without turning off a switch of the electric rotary tool after use. When the existing electric rotating tool is used again under the condition, because the switch is in a closed state, the electric rotating tool is started immediately after the power supply is directly connected, and when a user does not have psychological preparation, the electric rotating tool is directly started, so that personal injury is easily caused to the user.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is, how to avoid electric rotary tool direct start-up when forgetting access power under the condition of closing switch, cause the problem of injury to the operator.

In order to solve the above problem, the utility model provides an electric rotating tool protection circuit, include: the protection circuit comprises a first communication circuit board, a driving circuit, a power supply circuit and a power-on detection circuit; the first communication circuit board comprises a first connecting end, a second connecting end and a third connecting end;

the first connecting end is electrically connected with the driving circuit, and the driving circuit is electrically connected with the motor;

the power supply circuit comprises a power supply and a switch, one end of the switch is electrically connected with the power supply, and the other end of the switch is electrically connected with the second connecting end;

the third connecting end is connected with the power-on detection circuit, the power-on detection circuit is used for transmitting level signals of the third connecting end, and the first communication circuit board is used for receiving the level signals, wherein the level signals comprise high level signals and low level signals.

Optionally, the motor includes a brush motor or a brushless motor, the protection circuit includes a first protection circuit or a second protection circuit, the brush motor is electrically connected to the first protection circuit, and the brushless motor is electrically connected to the second protection circuit.

Optionally, the first protection circuit includes a first driving circuit and a first power-on detection circuit, the first connection end is electrically connected to the first driving circuit, the first driving circuit is electrically connected to the brush motor, and the third connection end is electrically connected to the first power-on detection circuit.

Optionally, the second protection circuit includes a second driving circuit, a second power-on detection circuit, and a motor back electromotive force detection circuit, the first connection end is electrically connected to the second driving circuit through the motor back electromotive force detection circuit, the second driving circuit is electrically connected to the brushless motor, and the third connection end is electrically connected to the second power-on detection circuit.

Optionally, the first power-on detection circuit includes a first capacitor, a first power tube, a first voltage regulator tube, a first resistor and a second resistor, the first resistor is electrically connected to a negative electrode of the first voltage regulator tube, one end of the second resistor, one end of the first capacitor and a gate of the first power tube, respectively, an anode of the first voltage regulator tube, the other end of the second resistor and the other end of the first capacitor are electrically connected to a source of the first power tube, respectively, and a drain of the first power tube is electrically connected to the third connection terminal.

Optionally, the second power-on detection circuit includes a second capacitor, a third capacitor, a second voltage-regulator tube, a third resistor, and a fourth resistor, the second capacitor and the third capacitor are connected in parallel and then connected in series with the third resistor, an anode of the second voltage-regulator tube is grounded, and a cathode of the second voltage-regulator tube is electrically connected to one end of the third resistor and one end of the fourth resistor respectively and then electrically connected to the third connection end.

Optionally, the first driving circuit comprises: the power supply comprises a second power tube, a third power tube, a first triode, a second triode, a third triode, a fifth resistor and a sixth resistor;

the base electrode of the first triode is electrically connected with the collector electrode of the second triode, and the emitter electrode of the first triode is electrically connected with the base electrode of the third triode;

one end of the fifth resistor is electrically connected with the collector of the third triode, and the other end of the fifth resistor is electrically connected with the grid of the second power tube;

one end of the sixth resistor is electrically connected with the collector of the third triode, and the other end of the sixth resistor is electrically connected with the grid of the third power tube;

and the drain electrode of the second power tube and the drain electrode of the third power tube are respectively electrically connected with the brush motor.

Optionally, the second driving circuit includes a second communication circuit board and at least three single driving circuits, each single driving circuit includes a fourth power tube, a fifth power tube, a sixth power tube and a seventh power tube, wherein a gate of the fourth power tube and a gate of the sixth power tube are electrically connected to the second communication circuit board, a drain of the fourth power tube is electrically connected to a drain of the fifth power tube, a source of the fourth power tube and a source of the fifth power tube are electrically connected to the drain of the sixth power tube and the drain of the seventh power tube, and then electrically connected to the brushless motor, and a gate of the fifth power tube and a gate of the seventh power tube are electrically connected to the motor back electromotive force detection circuit.

Optionally, the protection circuit further includes a current detection circuit, the current detection circuit includes a fourth capacitor, a fifth capacitor, a seventh resistor, an eighth resistor, and a ninth resistor, and the first communication circuit board further includes a fourth connection end and a fifth connection end;

one end of the fourth capacitor is electrically connected with one end of the seventh resistor and the fourth connecting end respectively, and the other end of the fourth capacitor is grounded;

one end of the fifth capacitor is electrically connected with one end of the eighth resistor and the fifth connecting end respectively, and the other end of the fifth capacitor is grounded;

one end of the ninth resistor is electrically connected with the other end of the eighth resistor, and the other end of the ninth resistor and the other end of the seventh resistor are electrically connected to an AGND point;

the current detection circuit is electrically connected with the drive circuit through the AGND point.

Compared with the prior art, the utility model discloses a power supply circuit's switch connection power and first communication circuit board, the motor is connected to the first communication circuit board other end is connected to drive circuit's one end, sets up electric detection circuitry simultaneously for to the level signal of first communication circuit board transmission third link, level signal is as drive signal, prevents to move immediately after the motor inserts the power. For example, after the power supply is connected, the power-on detection circuit transmits a high-level signal or a low-level signal to the first communication circuit board, the first communication circuit board receives the low-level signal as a driving signal and transmits the driving signal to the driving circuit, the motor operates after the switch is closed, the first communication circuit board receives the high-level signal as a driving signal and transmits the driving signal to the driving circuit, the motor does not operate, the motor is prevented from being immediately operated after the power supply is connected, the user is easily injured, and the safety of the user is protected.

On the other hand, the utility model also provides an electric rotary tool, include as above electric rotary tool protection circuit.

Compared with the prior art, the electric rotary tool has the same advantages as the electric rotary protection tool, and the details are not repeated herein.

Drawings

Fig. 1 is a schematic connection diagram of a protection circuit of an electric rotary tool according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a speed and power display circuit of the electric rotary tool protection circuit according to the embodiment of the present invention;

fig. 3 is a schematic diagram of a second power supply circuit of the electric rotary tool protection circuit according to the embodiment of the present invention;

fig. 4 is a schematic diagram of a first power-on detection circuit of the electric rotary tool protection circuit according to the embodiment of the present invention;

fig. 5 is a schematic diagram of a second power-on detection circuit of the electric rotary tool protection circuit according to the embodiment of the present invention;

fig. 6 is a schematic diagram of a first driving circuit of a protection circuit for an electric rotary tool according to an embodiment of the present invention;

fig. 7 is a schematic diagram of a second driving circuit of the electric rotary tool protection circuit according to the embodiment of the present invention;

fig. 8 is a schematic diagram of a current detection circuit of the protection circuit for an electric rotary tool according to the embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below. While certain embodiments of the present invention have been illustrated in the accompanying drawings, it is to be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided for a more thorough and complete understanding of the present invention. It should be understood that the drawings and examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

It should be understood that the various steps recited in the method embodiments of the present invention may be performed in a different order and/or performed in parallel. Moreover, method embodiments may include additional steps and/or omit performing the illustrated steps. The scope of the present invention is not limited in this respect.

The term "include" and variations thereof as used herein are open-ended, i.e., "including but not limited to". The term "based on" is "based, at least in part, on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "alternative embodiments". Relevant definitions for other terms will be given in the following description. It should be noted that the terms "first", "second", and the like in the present invention are only used for distinguishing different devices, modules, or units, and are not used for limiting the order or interdependence of the functions performed by the devices, modules, or units.

It is noted that references to "a" or "an" or "the" in the present disclosure are intended to be illustrative rather than limiting, and those skilled in the art will appreciate that references to "one or more" are intended to be exemplary and not limiting unless the context clearly indicates otherwise.

When a power-driven rotary tool such as an electric angle grinder or an electric saw is used for work, a situation that a power supply is directly cut off to cut off power supply without turning off a switch of the power-driven rotary tool after use due to negligence of a user often occurs. When the conventional electric rotating tool is used again under the condition, the switch is in a closed state, and the electric rotating tool is started immediately after being directly connected to a power supply, so that a user can easily cause personal injury when the user does not know that the switch is closed and psychological preparation is not available.

In order to solve the above problem, an embodiment of the present invention provides a protection circuit for an electric rotary tool, as shown in fig. 1, the protection circuit for an electric rotary tool includes:

the protection circuit comprises a first communication circuit board, a driving circuit, a power supply circuit and a power-on detection circuit; the first communication circuit board comprises a first connecting end, a second connecting end and a third connecting end;

the first connecting end is electrically connected with a driving circuit which is electrically connected with a motor;

the power supply circuit comprises a power supply and a switch, one end of the switch is electrically connected with the power supply, and the other end of the switch is electrically connected with the second connecting end;

the third connecting end is connected with a power-on detection circuit, the power-on detection circuit is used for transmitting level signals of the third connecting end, and the first communication circuit board is used for receiving the level signals, wherein the level signals comprise high level signals and low level signals.

In one embodiment, the first connection end of the first communication circuit board is electrically connected with a driving circuit, and the driving circuit is electrically connected with a motor and used for driving the motor to run; one end of a switch of the power supply circuit is electrically connected with the power supply, the other end of the switch is connected with the second connecting end of the first communication circuit board, the power supply circuit is used for supplying power to the first communication circuit, and the switch is used for realizing connection and disconnection of electric signals between the first communication circuit board and the power supply circuit; the third connecting end of the first communication circuit board is connected with the power-on detection circuit, and the power-on detection circuit generates a level signal and transmits the level signal of the third connecting end to the first communication circuit board, wherein the level signal comprises a high level signal and a low level signal.

Alternatively, the power supply may be a mobile power supply or a fixed power supply, for example, the mobile power supply may be a lithium battery power supply, and the fixed power supply may be a 220V alternating current power supply;

optionally, the protection circuit may further include a speed and power display circuit, the speed and power display circuit includes at least one filter resistor and a first LED indicator, one end of the first LED indicator is electrically connected to the first communication circuit board, and the other end of the first LED indicator is electrically connected to the filter resistor and the power supply circuit, and when the switch is in a closed state after the power supply is connected, the LED indicator is turned on; when the switch is in an off state, the first LED indicator light is not on, and the indication is provided for a user.

Optionally, as shown in fig. 2, the speed and power display circuit may further include a second filter resistor, a third filter resistor, a second LED indicator lamp and a third LED indicator lamp, and when the mobile power supply is used as the power supply, the remaining power of the mobile power supply is reflected according to the number of lighted indicator lamps, for example, when the voltage of the mobile power supply is above 18.5V, the first LED indicator lamp, the second LED indicator lamp and the third LED indicator lamp are all lighted to indicate that the power is sufficient; when the voltage of the mobile power supply is greater than or equal to 18V and less than 18.5V, the second LED indicator light and the third LED indicator light are turned on to indicate that the electric quantity is medium; when the voltage of the mobile power supply is greater than or equal to 16V and less than 18V, the power is low; when the voltage of the mobile power supply is more than 15V and less than 16V, only the third LED indicator lamp is turned on and flickers, and the electric quantity is extremely low; when the voltage of the mobile power supply is lower than 15V, only the third LED indicator lamp is turned on and flickers, but the motor cannot run at the moment.

Optionally, the speed and power display circuit may further include a fourth LED indicator, a fifth LED indicator and a sixth LED indicator for displaying the current motor speed, preferably, the fourth LED indicator lights up the output speed of the corresponding motor 558HZ, the fifth LED indicator lights up the output speed of the corresponding motor 606HZ, and the sixth LED indicator lights up the output speed of the corresponding motor 657 HZ.

In this embodiment, the power supply and the first communication circuit board are connected through the switch of the power supply circuit, and the power-on detection circuit is arranged to transmit the level signal of the third connection end of the first communication circuit board, and the level signal is used as a driving signal to prevent the motor from running immediately after being connected to the power supply. For example, after the power supply is connected, the power-on detection circuit transmits a high-level signal or a low-level signal to the first communication circuit board, the first communication circuit board receives the low-level signal as a driving signal and transmits the driving signal to the driving circuit, the motor operates after the switch is closed, the first communication circuit board receives the high-level signal as a driving signal and transmits the driving signal to the driving circuit, the motor does not operate, the motor is prevented from being immediately operated after the power supply is connected, the user is easily injured, and the safety of the user is protected.

Optionally, the motor includes a brush motor or a brushless motor, the protection circuit includes a first protection circuit or a second protection circuit, the brush motor is electrically connected to the first protection circuit, and the brushless motor is electrically connected to the second protection circuit.

In one embodiment, the brush motor of the present invention represents: a rotating electrical machine which incorporates a brush assembly to convert electrical energy into mechanical energy. The brush motor consists of two parts, stator and rotor, the stator has magnetic poles, winding or permanent magnet, the rotor has winding, after being powered on, the rotor also forms magnetic field, and the stator and rotor have included angle between their magnetic poles, so that the motor rotates under the mutual attraction of the stator and rotor magnetic fields.

The utility model discloses brushless motor that indicates shows: the rotor can be permanent magnet steel which is connected with the output shaft together with the shell, and the stator can be a winding coil.

Specifically, the electric rotary tool can select a brush motor or a brushless motor as torque output according to actual requirements, the working principles of the brush motor and the brushless motor are different, the protection circuits matched with the two motors are different, the brush motor is electrically connected with the first protection circuit, and the brushless motor is electrically connected with the second protection circuit.

In this embodiment, the brush motor is electrically connected to the first protection circuit or the brushless motor is electrically connected to the second protection circuit, and the corresponding motor and the adaptive protection circuit thereof are selected according to different requirements, so as to achieve the purpose of preventing the electric rotary tool from being immediately started after the electric rotary tool is directly connected to the power supply.

Optionally, the first protection circuit includes a first driving circuit and a first power-on detection circuit, the first connection end is electrically connected to the first driving circuit, the first driving circuit is electrically connected to the brush motor, and the third connection end is electrically connected to the first power-on detection circuit.

For convenience of distinguishing and describing, a first communication circuit board in the first protection circuit is marked as U1, a first connecting end of the first driving circuit electrically connected with the first communication circuit board U1 is marked as a 17 th pin, and a third connecting end of the first power-on detection circuit electrically connected with the first communication circuit board U1 is marked as a 2 nd pin.

In one embodiment, the first protection circuit comprises a first driving circuit and a first power-on detection circuit, the first driving circuit is electrically connected with the first communication circuit board U1 through a pin 17, and the first driving circuit is electrically connected with the brush motor and used for driving the brush motor; the first power-on detection circuit is electrically connected with the first communication circuit board U1 through a pin 2 and is used for transmitting a level signal of the pin 2 to the first communication circuit board U1.

Optionally, a power pin of the first communication circuit board is electrically connected to the capacitor C8, and the capacitor C8 is mainly used for filtering, filtering high-frequency interference radiated from the outside, and filtering pulse interference generated by the first communication circuit board when the first communication circuit board works.

In this embodiment, the protection circuit of the electric rotary tool with the brush motor is electrically connected to the first communication circuit board through one end of the first driving circuit, and the other end of the first driving circuit is electrically connected to the brush motor to drive the brush motor.

Optionally, the second protection circuit includes a second driving circuit, a second power-on detection circuit, and a motor back electromotive force detection circuit, the first connection end is electrically connected to the second driving circuit through the motor back electromotive force detection circuit, the second driving circuit is electrically connected to the brushless motor, and the third connection end is electrically connected to the second power-on detection circuit.

For convenience of distinguishing and description, a first communication circuit board in the second protection circuit is marked as U3A, and first connection ends of the back electromotive force detection circuit and the first communication circuit board U3A are marked as a 14 th pin, a 15 th pin and a 16 th pin; and a third connecting end of the second power-on detection circuit, which is electrically connected with the first communication circuit board U3A, is recorded as a 20 th pin.

In one embodiment, the second protection circuit comprises a second drive circuit, a second power-on detection circuit and a motor back electromotive force detection circuit, wherein the motor back electromotive force detection circuit is used for detecting the electrical angle position of the rotor of the brushless motor so as to execute phase conversion work; the second driving circuit is electrically connected with a 14 th pin, a 15 th pin and a 16 th pin of the first communication circuit board U3A through a back electromotive force detection circuit, and the second driving circuit is electrically connected with the brushless motor; the second electrifying detection circuit is electrically connected with the first communication circuit board U3A through a pin 20.

Alternatively, the counter electromotive force detection circuit is electrically connected to the second drive circuit through the U point, the V point, and the W point.

Optionally, as shown in fig. 3, the second protection circuit further includes a second power supply circuit, where the second power supply circuit includes at least one power transistor, at least one triode, at least two diodes, and at least one connection port; for convenience of distinguishing from description, the power tube is denoted as Q3, the triode is denoted as Q2, the two diodes are denoted as a diode D1 and a diode D7, and the connection port is denoted as a key interface. The drain electrode of the power tube Q3 is electrically connected with the positive electrode of the diode D1, the grid electrode of the power tube Q3 is electrically connected with the collector electrode of the triode Q2, the negative electrode of the diode is electrically connected with the emitting electrode of the triode Q2, the positive electrode of the diode is electrically connected with the key interface, and the power supply circuit is electrically connected with the first communication circuit board through the key interface. The diode D1 can prevent the voltage from flowing backwards after the power supply voltage is pulled down, and meanwhile, the power supply stability of the first communication circuit board is guaranteed.

In this embodiment, the electric rotary tool protection circuit using the brushless motor electrically connects the second driving circuit to the first connection terminal of the first communication circuit board through the back electromotive force detection circuit, so as to drive the brushless motor, and the second power-on detection circuit is electrically connected to the third connection terminal of the first communication circuit board, so as to transmit the level signal of the third connection terminal to the first communication circuit board, thereby forming the electric rotary tool protection circuit using the brushless motor, and achieving the purpose of preventing the electric rotary tool from being immediately started after the electric rotary tool is directly connected to the power supply.

Optionally, the first power-on detection circuit includes a first capacitor, a first power tube, a first voltage regulator tube, a first resistor and a second resistor, the first resistor is electrically connected to a negative electrode of the first voltage regulator tube, one end of the second resistor, one end of the first capacitor and a gate of the first power tube, respectively, an anode of the first voltage regulator tube, the other end of the second resistor and the other end of the first capacitor are electrically connected to a source of the first power tube, and a drain of the first power tube is electrically connected to the third connection terminal.

As shown in fig. 4, in an embodiment, for convenience of distinguishing and describing, a first capacitor in the first power-on detection circuit is denoted as C9, a first power tube is denoted as Q1, a first voltage regulator tube is denoted as ZD1, a first resistor is denoted as R15, and a second resistor is denoted as R16.

Preferably, the power transistor is an NMOS transistor.

Optionally, the positive electrode of the first voltage regulator tube ZD1 is grounded.

In an embodiment, the first resistor R15 is electrically connected to a negative electrode of the first voltage regulator tube ZD1, one end of the second resistor R16, one end of the first capacitor C9, and a gate of the first power tube Q1, the positive electrode of the first voltage regulator tube ZD1, the other end of the second resistor R16, and the other end of the first capacitor C9 are electrically connected to a source of the first power tube Q1, and a drain of the first power tube Q1 is electrically connected to the third connection terminal.

In the embodiment, when the power tube is driven, the gate of the power tube has stray capacitance, lead inductance and routing inductance, the input impedance is high, the inductance Q value is large, resonance is easy to occur, the gate charging current and the gate discharging current can be adjusted by connecting the first resistor and the second resistor, direct connection is prevented when the power tube is driven, and the power tube is not easy to resonate; meanwhile, a voltage regulator tube is arranged to prevent the circuit from being damaged due to overhigh potential, so that the stability of the first power-on detection circuit is facilitated.

Optionally, the second power-on detection circuit includes a second capacitor, a third capacitor, a second voltage-regulator tube, a third resistor and a fourth resistor, the second capacitor and the third capacitor are connected in parallel and then connected in series with the third resistor, an anode of the second voltage-regulator tube is grounded, and a cathode of the second voltage-regulator tube is electrically connected to one end of the third resistor and one end of the fourth resistor respectively and then electrically connected to the third connection end.

As shown in fig. 5, in an embodiment, for convenience of distinction and description, a second capacitor in the second power-on detection circuit is denoted as C32, a third capacitor is denoted as C33, a second voltage regulator tube is denoted as ZD2, a third resistor is denoted as R62, a fourth resistor is denoted as R63, and a third connection terminal is denoted as pin 20.

In an embodiment, the second capacitor C32 and the third capacitor C33 are connected in parallel and then connected in series with the third resistor R62, the anode of the second voltage regulator ZD2 is grounded, and the cathode of the second voltage regulator ZD2 is electrically connected to one end of the third resistor R62 and one end of the fourth resistor R63 respectively and then electrically connected to the 20 th pin. The second capacitor C32 and the third capacitor C33 are connected in parallel for filtering, and meanwhile, a voltage regulator tube is arranged to prevent the circuit from being damaged due to overhigh potential, so that the stability of the second electrifying detection circuit is facilitated.

Optionally, the first drive circuit comprises: the power supply comprises a second power tube, a third power tube, a first triode, a second triode, a third triode, a fifth resistor and a sixth resistor;

the base electrode of the first triode is electrically connected with the collector electrode of the second triode, and the emitter electrode of the first triode is electrically connected with the base electrode of the third triode;

one end of a fifth resistor is electrically connected with the collector of the third triode, and the other end of the fifth resistor is electrically connected with the grid of the second power tube;

one end of the sixth resistor is electrically connected with the collector of the third triode, and the other end of the sixth resistor is electrically connected with the grid of the third power tube;

and the drain electrode of the second power tube and the drain electrode of the third power tube are respectively and electrically connected with the brush motor.

As shown in fig. 6, in an embodiment, for convenience of distinction and description, the second power transistor is denoted as Q2, the third power transistor is denoted as Q3, the first triode is denoted as Q4, the second triode is denoted as Q5, the third triode is denoted as Q6, the fifth resistor is denoted as R18, and the sixth resistor is denoted as R19;

specifically, the base electrode of the first triode Q4 is electrically connected with the collector electrode of the second triode Q5, and the emitter electrode of the first triode Q4 is electrically connected with the base electrode of the third triode Q6; one end of a fifth resistor R18 is electrically connected with the collector of the third triode Q6, and the other end of the fifth resistor R18 is electrically connected with the grid of the second power tube Q2; one end of the sixth resistor R19 is electrically connected to the collector of the third triode Q6, and the other end of the sixth resistor R19 is electrically connected to the gate of the third power transistor Q3; the drain electrode of the second power tube Q2 and the drain electrode of the third power tube Q3 are respectively and electrically connected with the brush motor.

Optionally, the first driving circuit further includes a capacitor C10 and a capacitor C11, the capacitor C10 is electrically connected to one end of the fifth resistor R18, one end of the capacitor C11 is electrically connected to one end of the sixth resistor R19 and the gate of the third power transistor Q3, respectively, and the other end of the capacitor C10 and the other end of the capacitor C11 are electrically connected to the AGND point. The capacitor C10 and the capacitor C11 can effectively improve the interference resistance of the second power tube Q2 and the third power tube Q3, and effectively filter switching actions caused by jitter.

Optionally, the first driving circuit further includes a resistor R20 and a resistor R21, a collector of the third transistor Q6 is electrically connected to one end of the resistor R20, one end of the resistor R21 is electrically connected to a base of the third transistor Q6, and the other end of the resistor R21 is electrically connected to an emitter of the third transistor Q6, where the resistor R20 plays a role of current limiting, and the resistor R21 is a pull-down resistor, so as to increase a turn-off speed of the third transistor Q6.

In one embodiment, the first driving circuit implements the operation and stop of the brush motor by the switches of the second power transistor Q2 and the third power transistor Q3; the fifth resistor R18 and the sixth resistor R19 are respectively used for adjusting the switching rates of the second power tube Q2 and the third power tube Q3, reducing the ringing phenomenon of the grid electrode of the power tube and improving the stability of the first driving circuit.

Optionally, the second driving circuit includes a second communication circuit board and at least three single driving circuits, each single driving circuit includes a fourth power tube, a fifth power tube, a sixth power tube and a seventh power tube, wherein a gate of the fourth power tube and a gate of the sixth power tube are electrically connected to the second communication circuit board, a drain of the fourth power tube is electrically connected to a drain of the fifth power tube, a source of the fourth power tube and a source of the fifth power tube are electrically connected to the drain of the sixth power tube and the drain of the seventh power tube, and then electrically connected to the brushless motor, and a gate of the fifth power tube and a gate of the seventh power tube are electrically connected to the motor back electromotive force detection circuit.

As shown in fig. 7, in one embodiment, for convenience of distinction and description, the second communication circuit board of the single-item driving circuit is denoted as U3B, the fourth power transistor is denoted as Q4, the fifth power transistor is denoted as Q10, the sixth power transistor is denoted as Q5, and the seventh power transistor is denoted as Q11.

Optionally, the single-phase driving circuit further includes a resistor R31 and a resistor R40, one end of the resistor R31 is electrically connected to the second communication circuit board U3B, the other end of the resistor R31 is electrically connected to the gate of the fourth power transistor Q4, one end of the resistor R40 is electrically connected to the gate of the fourth power transistor Q4, and the other end of the resistor R40 is electrically connected to the source of the fourth power transistor Q4. The resistor R31 is used for reducing oscillation, reducing peak current of grid charging and preventing drain-source breakdown of the fourth power tube Q4; the resistor R40 can be regarded as a pull-down resistor, so that the gate level of the fourth power transistor Q4 has a reference ground, thereby improving the level stability and preventing accidental turn-on.

In the embodiment, the gate of the fourth power transistor Q4 and the gate of the sixth power transistor Q5 are electrically connected to the second communication circuit board U3B, the drain of the fourth power transistor Q4 is electrically connected to the drain of the fifth power transistor Q10, the source of the fourth power transistor Q4 and the source of the fifth power transistor Q10 are electrically connected to the drain of the sixth power transistor Q5 and the drain of the seventh power transistor Q11, respectively, and then electrically connected to the brushless motor, and the gate of the fifth power transistor Q10 and the gate of the seventh power transistor Q11 are electrically connected to the motor back electromotive force detection circuit, respectively. The fourth power tube Q4, the fifth power tube Q10, the sixth power tube Q5 and the seventh power tube Q11 form a full bridge driving circuit, which is used for reducing current fluctuation and torque ripple, so that the motor outputs a larger torque. The first communication circuit board outputs high level or low level to enable each power tube of the second driving circuit to be switched on or switched off through the second communication circuit board U3B, and therefore the forward and reverse rotation and the starting and stopping of the brushless motor are achieved.

Optionally, the protection circuit further includes a current detection circuit, the current detection circuit includes a fourth capacitor, a fifth capacitor, a seventh resistor, an eighth resistor, and a ninth resistor, and the first communication circuit board further includes a fourth connection end and a fifth connection end;

one end of a fourth capacitor is electrically connected with one end of the seventh resistor and the fourth connecting end respectively, and the other end of the fourth capacitor is grounded;

one end of a fifth capacitor is electrically connected with one end of the eighth resistor and the fifth connecting end respectively, and the other end of the fifth capacitor is grounded;

one end of the ninth resistor is electrically connected with the other end of the eighth resistor, and the other end of the ninth resistor and the other end of the seventh resistor are electrically connected to the AGND point;

the current detection circuit is electrically connected to the drive circuit via the AGND point.

As shown in fig. 8, in an embodiment, for convenience of description, a fourth capacitor of the current detection circuit is denoted as C2, a fifth capacitor is denoted as C5, a seventh resistor is denoted as R4, an eighth resistor is denoted as R10, and a ninth resistor is denoted as R11; recording a fourth connecting end of the first communication circuit board as an IPeak interface and recording a fifth connecting end as an IRms interface;

in this embodiment, one end of the fourth capacitor C2 is electrically connected to one end of the seventh resistor R4 and the fourth connection terminal IPeak interface, respectively, and the other end of the fourth capacitor C2 is grounded; one end of a fifth capacitor C5 is electrically connected with one end of the eighth resistor R10 and the fifth connection end IRms interface respectively, and the other end of the fifth capacitor C5 is grounded; one end of the ninth resistor R11 is electrically connected to the other end of the eighth resistor R10, and the other end of the ninth resistor R11 and the other end of the seventh resistor R4 are electrically connected to the AGND point; the seventh resistor R4, the eighth resistor R10 and the ninth resistor R11 are used for voltage division; the current detection circuit is electrically connected with the driving circuit through the AGND point and is used for monitoring the current of the driving circuit and avoiding the damage to the motor caused by the continuous heating of the overlarge current due to the motor stalling.

Another embodiment of the present invention provides an electric rotary tool, including the electric rotary tool protection circuit as described above.

In this embodiment, the electric rotary tool has all the effects of the protection circuit of the electric rotary tool, and will not be described herein again.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the disclosure, and these changes and modifications are intended to fall within the scope of the disclosure.

Claims (10)

1. A power rotary tool protection circuit, comprising: the protection circuit comprises a first communication circuit board, a driving circuit, a power supply circuit and a power-on detection circuit; the first communication circuit board comprises a first connecting end, a second connecting end and a third connecting end;

the first connecting end is electrically connected with the driving circuit, and the driving circuit is electrically connected with the motor;

the power supply circuit comprises a power supply and a switch, one end of the switch is electrically connected with the power supply, and the other end of the switch is electrically connected with the second connecting end;

the third connecting end is connected with the power-on detection circuit, the power-on detection circuit is used for transmitting level signals of the third connecting end, and the first communication circuit board is used for receiving the level signals, wherein the level signals comprise high level signals and low level signals.

2. The electric rotary tool protection circuit of claim 1, wherein the motor comprises a brush motor or a brushless motor, the protection circuit comprises a first protection circuit or a second protection circuit, the brush motor is electrically connected to the first protection circuit, and the brushless motor is electrically connected to the second protection circuit.

3. The electric rotary tool protection circuit of claim 2, wherein the first protection circuit comprises a first drive circuit and a first power-up detection circuit, the first connection terminal is electrically connected to the first drive circuit, the first drive circuit is electrically connected to the brushed motor, and the third connection terminal is electrically connected to the first power-up detection circuit.

4. The electric rotary tool protection circuit according to claim 3, wherein the second protection circuit includes a second drive circuit, a second power-on detection circuit, and a motor back electromotive force detection circuit, the first connection terminal is electrically connected to the second drive circuit through the motor back electromotive force detection circuit, the second drive circuit is electrically connected to the brushless motor, and the third connection terminal is electrically connected to the second power-on detection circuit.

5. The electric rotary tool protection circuit according to claim 4, wherein the first power-on detection circuit comprises a first capacitor, a first power tube, a first voltage regulator tube, a first resistor and a second resistor, the first resistor is electrically connected with a negative electrode of the first voltage regulator tube, one end of the second resistor, one end of the first capacitor and a grid electrode of the first power tube, an anode of the first voltage regulator tube, the other end of the second resistor and the other end of the first capacitor are electrically connected with a source electrode of the first power tube, and a drain electrode of the first power tube is electrically connected with the third connection end.

6. The electric rotary tool protection circuit according to claim 5, wherein the second power-on detection circuit includes a second capacitor, a third capacitor, a second voltage regulator tube, a third resistor and a fourth resistor, the second capacitor and the third capacitor are connected in parallel and then connected in series with the third resistor, the anode of the second voltage regulator tube is grounded, and the cathode of the second voltage regulator tube is electrically connected to one end of the third resistor and one end of the fourth resistor respectively and then electrically connected to the third connection terminal.

7. The power rotary tool protection circuit of claim 6, wherein the first drive circuit comprises: the power supply comprises a second power tube, a third power tube, a first triode, a second triode, a third triode, a fifth resistor and a sixth resistor;

the base electrode of the first triode is electrically connected with the collector electrode of the second triode, and the emitter electrode of the first triode is electrically connected with the base electrode of the third triode;

one end of the fifth resistor is electrically connected with the collector of the third triode, and the other end of the fifth resistor is electrically connected with the grid of the second power tube;

one end of the sixth resistor is electrically connected with the collector of the third triode, and the other end of the sixth resistor is electrically connected with the grid of the third power tube;

and the drain electrode of the second power tube and the drain electrode of the third power tube are respectively and electrically connected with the brush motor.

8. The electric rotary tool protection circuit according to claim 7, wherein the second drive circuit includes a second communication circuit board and at least three single drive circuits, and the single drive circuits include a fourth power tube, a fifth power tube, a sixth power tube and a seventh power tube, wherein a gate of the fourth power tube and a gate of the sixth power tube are electrically connected to the second communication circuit board, respectively, a drain of the fourth power tube is electrically connected to a drain of the fifth power tube, a source of the fourth power tube and a source of the fifth power tube are electrically connected to the brushless motor after being electrically connected to a drain of the sixth power tube and a drain of the seventh power tube, respectively, and a gate of the fifth power tube and a gate of the seventh power tube are electrically connected to the motor back electromotive force detection circuit, respectively.

9. The electric rotary tool protection circuit according to any one of claims 1 to 8, wherein the protection circuit further comprises a current detection circuit including a fourth capacitor, a fifth capacitor, a seventh resistor, an eighth resistor, and a ninth resistor, the first communication circuit board further including a fourth connection terminal and a fifth connection terminal;

one end of the fourth capacitor is electrically connected with one end of the seventh resistor and the fourth connecting end respectively, and the other end of the fourth capacitor is grounded;

one end of the fifth capacitor is electrically connected with one end of the eighth resistor and the fifth connecting end respectively, and the other end of the fifth capacitor is grounded;

one end of the ninth resistor is electrically connected with the other end of the eighth resistor, and the other end of the ninth resistor and the other end of the seventh resistor are electrically connected to an AGND point;

the current detection circuit is electrically connected with the drive circuit through the AGND point.

10. An electric rotary tool characterized by comprising the electric rotary tool protection circuit according to any one of claims 1 to 9.

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