JP3060920U - Charger spark prevention protection circuit - Google Patents

Abstract

(57) [Summary] [Problem] At the moment when the battery is removed from the charger,
Provided is a spark generation prevention circuit for a charger that prevents generation of dangerous sparks. SOLUTION: A sensor terminal S and a plug 22 for sensing relative to a battery 10 and a charger 20 are provided. Thus, during the charging process, the charging circuit 30 in the charger constantly detects whether or not the battery 10 has been removed from the insertion hole. When unplugged, the power is turned off in a very short time and no voltage is transmitted to the terminals on charger 20. In this way, a spark is generated at the moment when the battery 10 is removed from the charger 20, and a short circuit is prevented.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a spark prevention and protection circuit for a kind of charger. Particularly, the present invention relates to a spark generation prevention circuit of a charger for preventing a dangerous spark from being generated at the moment when a battery is removed from the charger.

[0002]

[Prior art]

 In the use of electric tools such as electric drills and electric screwdrivers, in order to escape the restrictions of cords, widen the range of use, and achieve more convenient use, the design of a power supply system using a battery is currently the mainstream. I have. On the other hand, there are the following three types of conventional chargers. The first is to adopt a transformer system. If this type of method is applied to a high wattage charger, the volume of the transformer will be enormous, which will significantly increase the overall weight of the charger. This is very inconvenient. Moreover, when applied to a universal charger capable of charging a battery of 7.2 V, 9.6 V, 16 V, etc., there are many parts that need to be added in the design, and naturally the cost is also high. Up significantly. Second, an electronic exchange system is adopted. The cost of this type of charger is very high and not suitable for general products. The third one adopts a capacitance charging method. This type of scheme is the most economical and the lightest. However, often due to improper design, sparks (arcs) are generated on the terminals when the battery is removed from the charger, which is extremely dangerous. There is even the danger that the charger itself will burn.

[0003]

[Problems to be solved by the invention]

 SUMMARY OF THE INVENTION In order to improve various disadvantages of the above-mentioned known structure, an object of the present invention is to provide a protection circuit for preventing sparking of a charger. It installs sensor terminals and plugs that sense relative to the battery and charger. Thus, during the charging process, the charging circuit in the charger constantly detects whether the battery has been removed from the insertion hole. When unplugged, disconnect the power supply in a very short time and do not transfer any voltage to the terminals on the charger. In this way, a spark is generated when the battery is removed from the charger, preventing the circuit from being short-circuited.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides the following spark prevention and protection circuit for a charger. It mainly includes batteries, chargers and charging circuits. The battery is provided with positive and negative terminal charging contacts and a sensor terminal, and the charger is formed with a plug for inserting the charging contact and the sensor terminal. Moreover, there is an altitude difference between the positive and negative terminal charging contacts and the sensor terminal. A silicon controlled rectifier and an IC circuit are installed in the charging circuit, and the silicon controlled rectifier is installed between a power supply and a positive terminal charging contact. The IC circuit includes a sensor connection leg and a control signal leg. The sensor connection leg is connected to the sensor terminal and is used to determine a battery removal operation. The control signal leg is connected to the control terminal of the silicon controlled rectifier and is used for controlling the energized state of the silicon controlled rectifier. During the charging process, the IC circuit constantly reads the voltage change of the sensor connection leg to determine whether or not the removal operation is performed. If the sensor terminal disconnects from the charger, the circuit determines that the battery has already been disconnected and immediately disconnects the silicon controlled rectifier, even if the positive and negative charging contacts of the battery are still in contact with the charger plug. I do. As a result, the charger stops the power output and no spark occurs.

[0005]

[Embodiment of the invention]

 As shown in FIG. 1, the present invention mainly includes a battery 10, a charger 20, and a charging circuit 30. An insertion portion 11 is provided at a lower end of the battery 10. The inside of the insertion portion 11 includes contacts B + and B− that are positive and negative terminals of a power supply, and a sensor terminal S. An altitude difference exists between the charging contacts B +, B- and the sensor terminal S (the sensor terminal S is low). The charger 20 has a concave installation space 21 in which the battery 10 is inserted. A plug 22 corresponding to the charging contacts B + and B− and the sensor terminal S is installed in the concave installation space 21.

Next, as shown in FIG. 2, a silicon controlled rectifier is installed in the charging circuit 30. The output voltage of the rectifier 31 is connected to the silicon controlled rectifier, and the output of the silicon controlled rectifier is connected to the positive terminal charging contact B +. The control end of the silicon controlled rectifier is connected to two series light emitting diodes and a voltage stabilizer 32. The light emitting diode indicates the charging status of the charger 20. The voltage stabilizing circuit 32 generates a working voltage required by the IC circuit 33, transmits the working voltage to the sensor connection leg A of the IC circuit 33, and uses it as a reference voltage for detection. The IC circuit 33 is a main control unit, and its sensor connection leg A is connected to the sensor terminal S. When the battery 10 is inserted into the charger 20 and after the battery 10 is removed from the charger 20 (or not inserted). Is used to compare the voltage change on the sensor terminal S. Based on the sensing, if the voltage of the sensor terminal S after the battery 10 is inserted is higher than that when the battery 10 is not inserted (that is, the sensor reference voltage), the IC circuit 33 determines whether the battery 10 is removed due to this voltage change. Determine whether or not. In addition, the sensing is performed using an altitude difference between the positive and negative terminal charging contacts B +, B− and the sensor terminal S of the battery. When the sensor terminal S leaves the charger 20, it is determined that the battery has already been removed even if the positive and negative terminal charging contacts B + and B- of the battery are still in contact with the plug 22 of the charger 20. Also, the IC circuit 33 is provided with a control signal leg C, which is connected to the control terminal of the silicon controlled rectifier. During the charging time, the pulse signal is continuously transmitted, the energized state of the silicon controlled rectifier is maintained, and the charging voltage is transmitted to the positive terminal charging contact B +. When the battery 10 is removed, the sensor connection leg A senses a voltage change on the sensor terminal S, and the IC circuit 33 stops outputting the control signal leg C. Subsequently, the silicon controlled rectifier is disconnected, and the transmission of the charging voltage is stopped.

Further, as shown in FIG. 3, during the charging process, the IC circuit 33 constantly reads the voltage change of the sensor connection leg (40). If the removal of the battery 10 is detected (41), the output of the control signal leg is stopped within a very short time (2 ms in this embodiment), and the silicon control rectifier is disconnected (42). All voltage output of the charger 20 is stopped. Therefore, no spark occurs at the moment when the battery 10 is removed. Further, the IC circuit 33 checks the charging voltage again (43). If there is no charging voltage, the disconnection of the silicon controlled rectifier is maintained for an appropriate time (5 ms in this embodiment), and then the charging is performed. The voltage output is restored (44). If the charging voltage indicates that a situation such as failure or aging of electronic components may occur (45), the light emitting diode lights up and a warning is issued.

[0008]

[Effect of the invention]

 In the present invention, a sensor terminal and a plug are installed for the battery and the charger, which correspond to each other. With this structure, the charging circuit in the charger continuously searches for the removal of the battery during the charging process. When removal is detected, the power supply is momentarily turned off and no voltage is transmitted to the terminals on the charger. In this way, a spark is generated when the battery is removed from the charger, preventing the circuit from being short-circuited. As mentioned above, in addition to providing practical effects, the present invention has a completely new design, and is equipped with inventive step and originality.

[Brief description of the drawings]

FIG. 1 is an exploded view of the present invention.

FIG. 2 is a detailed circuit diagram of a charger.

FIG. 3 is an operation flowchart of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Battery 11 Insertion / attachment part 20 Charger 21 Recessed installation space 22 Outlet 30 Charging circuit 31 Rectifier 32 Voltage stabilization circuit 33 IC circuit 40 Read voltage change of battery sensor terminal 41 Battery removal 42 Silicon controlled rectifier disconnection 43 Check charging voltage 44 Recover the charging standby state of the charger 45 Error display

Claims (4)

[Utility model registration claims] 1. A spark prevention and protection circuit for a charger mainly including a battery, a charger, and a charging circuit, wherein the battery is provided with positive and negative terminal charging contacts, and a sensor terminal. A plug for inserting the charging contact and the sensor terminal is formed, and there is an altitude difference between the positive and negative terminal charging contacts and the sensor terminal; a silicon controlled rectifier and an IC circuit in the charging circuit. The silicon control rectifier is installed between a power supply and the positive terminal charging contact, the IC circuit includes a sensor connection leg, and a control signal leg, the sensor connection leg is connected to the sensor terminal, and the battery is connected to the sensor terminal. The control signal leg is connected to the control terminal of the silicon controlled rectifier, and is used for controlling the energized state of the silicon controlled rectifier. During the charging process, the IC circuit is connected to the sensor connection. Continuously read the voltage change of the continuation leg, judge the presence or absence of removal operation,
When the sensor terminals disconnect from the charger, if the positive and negative terminal charging contacts of the battery are still in contact with the plug of the charger, the circuit senses and determines that the battery has been removed. Wherein the silicon controlled rectifier is immediately disconnected, the charger stops outputting power, and no spark is generated. 2. The IC circuit, after removing the battery, the control signal leg controls the silicon controlled rectifier and disconnects it for an appropriate period of time, after which the silicon controlled rectifier is energized and the charging voltage output is recovered. The spark prevention and protection circuit for a charger according to claim 1, wherein 3. The charging circuit includes a voltage stabilizing circuit, generates a working voltage required by the IC circuit, and transmits a sensing reference voltage to the sensor terminal of the IC circuit. The spark generation prevention and protection circuit for a charger according to claim 1. 4. The protection circuit according to claim 1, wherein when the voltage of the sensor terminal is higher than a reference voltage for sensing, it is determined that the battery is removed.