Anti-sparking circuit for electric tool

Abstract

The utility model discloses an anti-sparking circuit for an electric tool, which comprises a signal end electrically connected with a singlechip terminal, the signal end is connected with a switch element through an amplifying circuit, the switch element is connected in parallel with a large-resistance resistor, and the switch element tube controls the electric tool to start and stop. And the switch element is an MOS (Metal Oxide Semiconductor) tube Q10. The situation that electric sparks are generated due to the fact that transient current is too large when a high-power electric tool is started and stopped can be effectively prevented.

Description

Technical Field

[0001] The utility model relates to an anti - sparking circuit for power tools, belonging to the technical field of power tools. Background Art

[0002] To meet the needs of users, there are more and more high - power power tools. To drive high - power power tools, a battery pack with large current and high voltage is often required. The motor control system of existing power tools generally includes a large - capacity capacitor. When the battery pack is installed on the power tool, when the voltage at the capacitor terminal is low, the battery pack charges the capacitor, and this process will generate a transient large current, resulting in electric sparks between the connection terminals of the power tool and the connection terminals of the battery pack, thus easily damaging the circuit components.

[0003] Traditional circuits often set large - current switches to solve this problem. However, in the state of frequent use, the large - current switch may have problems such as contact ablation due to incomplete closing. Summary of the Utility Model

[0004] The purpose of the utility model is to overcome the problems existing in the prior art and provide an anti - sparking circuit for power tools, which can effectively prevent the situation of generating electric sparks due to excessive transient current when the high - power power tool starts and stops.

[0005] To solve the above - mentioned technical problems, an anti - sparking circuit for power tools of the utility model includes: a signal terminal electrically connected to the single - chip microcomputer terminal, the signal terminal is connected to a switching element through an amplifying circuit, the switching element is connected in parallel with a large - value resistor, and the switching element controls the start and stop of the power tool.

[0006] Further, the switching element is MOS transistor Q10.

[0007] Further, the signal terminal is connected to the base of transistor Q17 through resistor R59, the collector of transistor Q17 is connected to the base of transistor Q16 through resistor R55, and the emitter of transistor Q17 is grounded; the collector of transistor Q16 is connected to the gate of MOS transistor Q10 through resistor R27, the emitter of transistor Q16 is connected to a low voltage, and the collector of transistor Q16 is also connected to the source of MOS transistor Q10 through resistor R57.

[0008] Further, the drain of MOS transistor Q10 is connected to a high - voltage power supply through an energy - storage circuit, and the source of MOS transistor Q10 is grounded.

[0009] Further, the large - value resistor R19 is connected in parallel between the drain and the source of MOS transistor Q10.

[0010] Further, the energy storage circuit includes a capacitor C1 and a capacitor C2 connected in parallel.

[0011] Further, a resistor R61 is connected between the base and the emitter of the triode Q17, and a resistor R22 is connected between the emitter and the base of the triode Q16.

[0012] Compared with the prior art, the present utility model has achieved the following beneficial effects: it can effectively prevent the situation that large-power electric tools generate electric sparks due to excessive transient current during startup and shutdown. Description of the Drawings

[0013] The following further describes the present utility model in detail with reference to the drawings and specific embodiments. The drawings are only provided for reference and illustration, and are not intended to limit the present utility model.

[0014] Figure 1 is the logic block diagram of the present utility model;

[0015] Figure 2 is the circuit diagram of the present utility model. Detailed Embodiments

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model.

[0017] As Figure 1 shown, the present utility model aims to provide an anti-spark circuit for an electric tool, including: a signal terminal electrically connected to the terminal of a single-chip microcomputer, the signal terminal is connected to a switching element through an amplifying circuit, the switching element is connected in parallel with a large-value resistor, and the switching element controls the startup and shutdown of the electric tool.

[0018] As Figure 2 shown, the switching element is an NMOS transistor Q10. The signal terminal is connected to the base of the triode Q17 through a resistor R59. The collector of the triode Q17 is connected to the base of the triode Q16 through a resistor R55. The emitter of the triode Q17 is grounded; the collector of the triode Q16 is connected to the gate of the MOS transistor Q10 through a resistor R27. The emitter of the triode Q16 is connected to the +12V power supply. The collector of the triode Q16 is also connected to the source of the MOS transistor Q10 through a resistor R57.

[0019] The drain of the MOS transistor Q10 is connected to a 42V voltage through an energy storage circuit. The energy storage circuit includes a capacitor C1 and a capacitor C2 connected in parallel. The source of the MOS transistor Q10 is grounded. The energy storage circuit can protect the switching element from being ablated during the startup and shutdown of the electric tool, but cannot control the delayed startup of the electric tool.

[0020] A high-value resistor R19 is connected in parallel between the drain and source of the MOS transistor Q10. When the switching element MOS transistor Q10 is not conducting, the resistor R19 powers on other components with a small current, so that the power tool can be turned on immediately without being affected by the delayed conduction of the MOS transistor Q10.

[0021] A resistor R61 is connected between the base and emitter of the triode Q17, and a resistor R22 is connected between the emitter and base of the triode Q16. The anti-spark circuit is controlled to conduct with a delay through the delay signal output by the single-chip microcomputer, thus avoiding the generation of electric sparks when the battery pack is inserted into the power tool.

[0022] The above are only the preferred and feasible embodiments of the present invention, which show and describe the basic principles, main features and advantages of the present invention. The patent protection scope of the present invention is not limited thereby. Those skilled in the art should understand that the present invention is not restricted by the above embodiments. Except for the above embodiments, without departing from the spirit and scope of the present invention, the present invention may have other implementation manners. The present invention will also have various changes and improvements. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention. The protection scope required by the present invention is defined by the appended claims and their equivalents. The technical features not described in the present invention can be realized by or adopted the existing technologies, and will not be elaborated herein.

Claims

1. An anti-spark circuit for an electric tool, comprising: A signal end electrically connected to a terminal of the single chip computer, the signal end is connected to a switch element through an amplifier circuit, the switch element is connected in parallel with a large resistance, and the switch element controls the start and stop of the electric tool.

2. The anti-spark circuit for electric tools according to claim 1, characterized in that: The switch element is a MOS tube Q10.

3. The anti-spark circuit for electric tools according to claim 2, characterized in that: The signal end is connected to the base of the transistor Q17 through the resistor R59, the collector of the transistor Q17 is connected to the base of the transistor Q16 through the resistor R55, and the emitter of the transistor Q17 is grounded; the collector of the transistor Q16 is connected to the gate of the MOS transistor Q10 through the resistor R27, the emitter of the transistor Q16 is connected to a low voltage, and the collector of the transistor Q16 is also connected to the source of the MOS transistor Q10 through the resistor R57.

4. The anti-spark circuit for electric tools according to claim 2, characterized in that: The drain of the MOS transistor Q10 is connected to a high voltage power supply through an energy storage circuit, and the source of the MOS transistor Q10 is grounded.

5. The anti-spark circuit for electric tools according to claim 3, characterized in that: The large resistance resistor R19 is connected in parallel between the drain and the source of the MOS transistor Q10.

6. The anti-spark circuit for electric tools according to claim 4, characterized in that: The energy storage circuit includes a capacitor C1 and a capacitor C2 connected in parallel.

7. The anti-spark circuit for electric tools according to claim 3, characterized in that: A resistor R61 is connected between the base and the emitter of the transistor Q17, and a resistor R22 is connected between the emitter and the base of the transistor Q16.

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