阅读说明：本技术 电动工具控制器的防意外启动电路 (Accidental start prevention circuit of electric tool controller ) 是由 刘庆江 于盛 李军建 于 2019-11-21 设计创作，主要内容包括：本发明涉及到一种电动工具控制器的防意外启动电路,包括串联在电动工具电池包B+端子上的第一电阻和电容,第一电阻位于B+端子和电容之间,电容另一端接地,第一电阻和电容之间通过一个开关与单片机电性连接。本发明利用单片机检测连接在电池包B+端子上的电容的电压,并根据电压变化曲线判断电动工具的启动属于正常启动还是意外启动,并根据判断结果对电机的动作进行控制,确保电机在电动工具意外启动时不工作、在正常启动时正常运转,从而有效提高电动工具的使用安全性。(The invention relates to an accidental start preventing circuit of an electric tool controller, which comprises a first resistor and a capacitor, wherein the first resistor and the capacitor are connected in series on a B + terminal of an electric tool battery pack, the first resistor is positioned between the B + terminal and the capacitor, the other end of the capacitor is grounded, and the first resistor and the capacitor are electrically connected with a single chip microcomputer through a switch. The invention utilizes the single chip microcomputer to detect the voltage of the capacitor connected to the terminal B + of the battery pack, judges whether the starting of the electric tool belongs to normal starting or accidental starting according to the voltage change curve, and controls the action of the motor according to the judgment result, thereby ensuring that the motor does not work when the electric tool is accidentally started and normally runs when the electric tool is normally started, and effectively improving the use safety of the electric tool.)

1. The accidental starting prevention circuit of the electric tool controller is characterized by comprising a first resistor (1) and a capacitor (2) which are connected in series on a B + terminal of an electric tool battery pack, wherein the first resistor (1) is located between the B + terminal and the capacitor (2), the other end of the capacitor (2) is grounded, and the first resistor (1) and the capacitor (2) are electrically connected with a single chip microcomputer (4) through a switch (3).

2. The circuit for preventing accidental start of a controller of an electric tool according to claim 1, characterized in that a second resistor (5) is connected in series between the switch (3) and the single chip microcomputer (4).

3. The circuit for preventing the accidental start of the electric tool controller according to claim 2, wherein a third resistor (6) is connected in parallel between the second resistor (5) and the single chip microcomputer (4), the other end of the third resistor (6) is grounded, and the resistance value of the third resistor (6) is smaller than that of the first resistor (1).

4. The circuit of claim 1, wherein the switch (3) comprises a first transistor (301) and a second transistor (302) connected in series, wherein the first transistor (301) is a PNP transistor, the second transistor (302) is an NPN transistor, an emitter of the first transistor (301) is connected between the first resistor (1) and the capacitor (2), a collector of the first transistor is connected to the second resistor (5), a base of the first transistor is connected to a collector of the second transistor (302), a base of the second transistor (302) is connected to a control switch of the power tool, and an emitter of the second transistor is grounded.

The technical field is as follows:

the invention relates to an accidental start preventing circuit of an electric tool controller.

Background art:

portable electric tool is more and more receiving user's favor because convenience, the flexibility of its use, but portable electric tool has a biggest drawback just to be the battery reserves restriction, and long in order to improve electric tool uses, can be equipped with two to three battery package for change for an electric tool usually, and when changing the battery, we discover, have a condition and can cause the injury to the user. Usually when the battery package electric quantity is not enough, the instrument can automatic shutdown, lead to the user to be difficult to judge whether the state of electric tool switch is the disconnection or the closure because electric tool loses the electricity this moment, if change the battery package then safe in the disconnection state, but if the switch directly changes the battery package in the closure state, then the electric tool that probably appears installing the battery package starts in the twinkling of an eye, because electric tool has great impact force, and some electric tool have the cutter, consequently, electric tool burst operation is very easy to hurt the user when installing the battery package.

The invention content is as follows:

the technical problem to be solved by the invention is as follows: the utility model provides an unexpected starting circuit of preventing of electric tool controller, this circuit plays a role in electric tool switch closed state installation battery package, restriction motor work to avoid the unexpected start-up of motor to cause the injury to the user.

In order to solve the technical problems, the invention adopts the technical scheme that: the accidental starting prevention circuit of the electric tool controller comprises a first resistor and a capacitor which are connected in series on a B + terminal of an electric tool battery pack, wherein the first resistor is located between the B + terminal and the capacitor, the other end of the capacitor is grounded, and the first resistor and the capacitor are electrically connected with a single chip microcomputer through a switch.

As a preferred scheme, a second resistor is further connected in series between the switch and the single chip microcomputer.

As a preferred scheme, a third resistor is connected in parallel between the second resistor and the singlechip, the other end of the third resistor is grounded, and the resistance value of the third resistor is smaller than that of the first resistor.

As a preferable scheme, the switch includes a first triode and a second triode which are connected in series, wherein the first triode is a PNP triode, the second triode is an NPN triode, an emitter of the first triode is connected between the first resistor and the capacitor, a collector of the first triode is connected with the second resistor, a base of the first triode is communicated with a collector of the second triode, a base of the second triode is connected to the control switch of the electric tool, and the emitter of the second triode is grounded.

The invention has the beneficial effects that: the invention utilizes the single chip microcomputer to detect the capacitance voltage variation trend when the electric tool is switched on and switched off, judges the electric tool to be started accidentally or normally according to the capacitance voltage variation trend, controls the motor according to the judgment result, limits the motor to work when the judgment result is the accidental start so as to ensure the personal safety of a user, and controls the motor to work when the judgment result is the normal start so as to ensure the normal use of the electric tool.

The invention further connects a second resistor between the switch and the singlechip to limit the current in the circuit, thereby avoiding the damage of the singlechip caused by overlarge current.

The invention further connects a third resistor in parallel between the second resistor and the single chip, and the other end of the third resistor is grounded, thereby reducing the voltage of the detection end of the single chip and further ensuring the use safety of the single chip.

The invention further uses the first triode and the second triode which are mutually connected in series as switches, thereby utilizing the control voltage to turn on or off the switches, and realizing the synchronous switching of the switch of the accidental starting prevention circuit and the switch of the electric tool.

Description of the drawings:

the following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

FIG. 1 is an electrical schematic of the present invention;

FIG. 2 is a graph of the change in capacitor voltage detected by the single chip during normal start-up of the power tool;

fig. 3 is a graph of the change of the capacitor voltage detected by the single chip microcomputer when the electric tool is accidentally started due to the battery pack installed in the switch closed state.

In fig. 1: 1. the circuit comprises a first resistor, a second resistor, a capacitor, a third resistor, a switch, a first triode, a second triode, a third triode, a singlechip, a second resistor, a third resistor and a fourth resistor.

The specific implementation mode is as follows:

specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the accidental start preventing circuit of the electric tool controller comprises a first resistor 1 and a capacitor 2 which are connected in series on a battery pack B + terminal of the electric tool, the first resistor 1 is positioned between the B + terminal and the capacitor 2, the other end of the capacitor 2 is grounded, the first resistor 1 and the capacitor 2 are electrically connected with a single chip microcomputer 4 through a switch 3, a second resistor 5 is connected in series between the switch 3 and the single chip microcomputer 4, a third resistor 6 is connected in parallel between the second resistor 5 and the single chip microcomputer 4, the other end of the third resistor 6 is grounded, and the resistance of the third resistor 6 is smaller than that of the first resistor 1.

The switch 3 comprises a first triode 301 and a second triode 302 which are mutually connected in series, wherein the first triode 301 is a PNP triode, the second triode 302 is an NPN triode, an emitting electrode of the first triode 301 is connected between a first resistor 1 and a capacitor 2, a collecting electrode is connected with a second resistor 5, a base electrode is communicated with a collecting electrode of the second triode 302, a base electrode of the second triode 302 is connected to a control switch of the electric tool, and the emitting electrode is grounded.

The working principle of the invention is as follows: as shown in fig. 1, when the battery pack is installed when the control switch of the power tool is turned off, B + is charged and charges the capacitor 2 through the first resistor 1 and is charged quickly while the battery pack is installed, which is about 2ms, so that it is impossible for an operator to close the control switch of the power tool in such a short time.

After the battery pack is installed, an operator closes a control switch of the electric tool, at the moment, the base electrode of the second triode 302 is electrified to form a high level, the collector electrode and the emitter electrode of the second triode 302 are enabled to be conducted, the base electrode of the first triode 301 is formed into a low level, the emitter electrode and the collector electrode of the first collector electrode 301 are further conducted, the switch 3 is conducted, the capacitor 2, the second resistor 5 and the third resistor 6 are conducted, the capacitor 2 starts to discharge, since the initial voltage of the capacitor 2 is higher, as the discharge time goes on and since the resistance of the third resistor 6 is smaller than that of the first resistor 1, therefore, the voltage detected by the single chip 4 is gradually reduced from the high voltage and then stabilized at a lower voltage value, forming a voltage trend chart as shown in fig. 2, under the condition, the singlechip 4 judges that the electric tool is normally started, and the singlechip 4 controls the motor to normally work.

When the control switch of the electric tool is closed to install the battery pack, B + is powered on and the base of the second triode 302 forms a high level to switch on the switch 3 when the battery pack is installed, at the moment, because the capacitor 2 is not powered yet, the terminal B + is still in a state of charging the capacitor 2, therefore, the voltage detected by the singlechip 4 is very low, along with continuous power supply of the battery pack, the voltage detected by the singlechip 4 gradually rises to a heightened level and then keeps balance, and a voltage trend graph as shown in figure 3 is formed, under the condition, the singlechip 4 judges that the electric tool is started accidentally, and the singlechip 4 controls the motor not to work.

How the single chip microcomputer 4 controls the motor to stop working or normally work can be realized through a relay connected with the motor driving circuit in series.

The above embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments in use, and are not intended to limit the invention; it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications belong to the protection scope of the present invention.