A switch closed power-on detection circuit

Abstract

The present invention relates to the field of detection circuit technology, and more specifically, to a switch-on power-up detection circuit. The circuit comprises a positive connection terminal B+, a negative connection terminal GND, a detection terminal AD_CHK, an auxiliary power supply terminal +5V, voltage stabilizing diodes D8 and D9, transistors Q4, Q5, and Q6, capacitors C25 and C26, and resistors R46, R47, R49, R50, R51, R52, R53, R54, and R55. The positive connection terminal B+ is connected to the positive terminal of a battery pack, the negative connection terminal GND is connected to the negative terminal of the battery pack, the detection terminal AD_CHK is connected to an MCU, and the MCU is used to detect changes in analog quantities at the detection terminal AD_CHK. The auxiliary power supply terminal +5V is connected to an auxiliary power circuit on a controller and also serves as the operating voltage of the MCU. In the switch-on power-up detection circuit, the MCU detects changes in analog quantities at capacitor C25 in the circuit, and is used to detect the switch status before the power tool is started. This ensures that the tool does not output power when the battery pack is installed when the tool's own switch is closed, thereby protecting the user.

Description

Technical Field

[0001] The present invention relates to the technical field of detection circuits, and in particular to a switch closing power-on detection circuit. Background Art

[0002] As electric (lithium-ion) tools become increasingly common in households, chainsaws, angle grinders, electric shears, and planers are becoming increasingly common. These tools have blades or grinding wheels on their output terminals, which can be harmful if used improperly. This is especially true when the battery pack is inserted while the switch is closed, creating a high risk of injury to the user.

[0003] There are two main existing solutions: 1. Using dual switches (one overcurrent switch and one signal switch); 2. Eliminating the self-locking function of the mechanical switch. The first solution has the drawback of increasing costs, reducing the probability of failure, and being unable to completely avoid it. The second solution also has the drawback of requiring constant pressure on the switch during normal use, which can easily fatigue the finger and make the user feel uncomfortable. Summary of the Invention

[0004] The object of the present invention is to provide a switch closure power-on detection circuit to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned objectives, the present invention provides a switch closed power-on detection circuit, including a positive electrode connection terminal B+, a negative electrode connection terminal GND, a detection terminal AD_CHK, an auxiliary power supply terminal +5V, voltage regulator diodes D8 and D9, transistors Q4, Q5, and Q6, capacitors C25 and C26, resistors R46, R47, R49, R50, R51, R52, R53, R54, and R55, the positive electrode connection terminal B+ is connected to the positive electrode of the battery pack, the negative electrode connection terminal GND is connected to the negative electrode of the battery pack, the detection terminal AD_CHK is connected to the MCU, the MCU is used to detect changes in the analog quantity at the detection terminal AD_CHK, and the auxiliary power supply terminal +5V is connected to the auxiliary power supply circuit on the controller, which is also the operating voltage of the MCU.

[0006] Preferably, the positive electrode connection terminal B+ is connected to the first pin of the Zener diode D9, the second pin of the Zener diode D9 is connected to one end of the resistor R46, the other end of the resistor R46 is connected to the second pin of the transistor Q5, the third pin of the transistor Q5 is connected to one end of the resistor R52, the other end of the resistor R52 is connected to the positive electrode connection terminal B+ and the first pin of the Zener diode D9, the third pin of the transistor Q5 is grounded, the resistor R52 is connected in parallel with the first pin and the third pin of the transistor Q5, the first pin and the third pin of the transistor Q5 are connected in parallel with the resistor R52, and a resistor R50 is connected in series between the first pin of the transistor Q5 and the resistor R52.

[0007] Preferably, the second pin of the transistor Q5 is connected to the second pin of the Zener diode D8 , and the first pin of the Zener diode D8 is connected to the capacitor C26 and grounded.

[0008] Preferably, the second pin of the transistor Q4 is connected to the first pin of the diode D8, the first pin and the second pin of the transistor Q4 are connected in parallel with R49, the first pin of the transistor Q4 is connected to one end of the resistor R53, the other end of the resistor R53 is connected to the third pin of the transistor Q6, the second pin of the transistor Q6 is connected to one end of the capacitor C25, the other end of the capacitor C25 is connected to the detection end AD_CHK, the other end of the detection end AD_CHK is connected to one end of the resistor R47, and the other end of the resistor R47 is connected to the third pin of the transistor.

[0009] Preferably, the capacitor C25 and the resistor R51 are connected in parallel, and the second pin of the transistor Q6 is grounded.

[0010] Preferably, the first pin of the transistor Q6 is connected to one end of the resistor R54, and the other end of the resistor R54 is connected to the auxiliary power supply terminal +5V.

[0011] Preferably, the first pin of the transistor Q6 is connected to one end of the resistor R55, and the other end of the resistor R55 is grounded.

[0012] Compared with the prior art, the present invention has the following beneficial effects: in the switch closed power-on detection circuit, the MCU detects the change in the AD_CHK analog quantity at the capacitor C25 in the circuit, which is used for switch status detection before the power tool is started, thereby achieving the effect of no output when the battery pack is installed when the tool's own switch is closed, thereby protecting the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a power-on detection circuit diagram of the present invention;

[0014] Figure 2 The oscilloscope displays a waveform diagram when the capacitor C26 of the present invention is charged;

[0015] Figure 3 For the present invention Figure 2 The waveform screenshots are in brackets;

[0016] Figure 4 The oscilloscope displays a waveform diagram when the auxiliary power supply of the present invention is powered;

[0017] Figure 5 For the present invention Figure 4 The waveform screenshots are in brackets;

[0018] Figure 6 The waveform diagram displayed by the oscilloscope when the switch of the present invention is in the closed state;

[0019] Figure 7 For the present invention Figure 6 The waveform screenshots are in square brackets. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] See also Figure 1-Figure 7 As shown, the present invention provides a technical solution:

[0022] The present invention provides a switch-closed power-on detection circuit, comprising a positive electrode connection terminal B+, a negative electrode connection terminal GND, a detection terminal AD_CHK, an auxiliary power supply terminal +5V, voltage-stabilizing diodes D8 and D9, transistors Q4, Q5, and Q6, capacitors C25 and C26, and resistors R46, R47, R49, R50, R51, R52, R53, R54, and R55. The positive electrode connection terminal B+ is connected to the positive electrode of a battery pack, the negative electrode connection terminal GND is connected to the negative electrode of the battery pack, the detection terminal AD_CHK is connected to an MCU, and the MCU is used to detect changes in an analog quantity at the detection terminal AD_CHK. The auxiliary power supply terminal +5V is connected to an auxiliary power supply circuit on a controller and is also the operating voltage of the MCU.

[0023] In this embodiment, the positive electrode connection terminal B+ is connected to the first pin of the Zener diode D9, the second pin of the Zener diode D9 is connected to one end of the resistor R46, the other end of the resistor R46 is connected to the second pin of the transistor Q5, the third pin of the transistor Q5 is connected to one end of the resistor R52, the other end of the resistor R52 is connected to the positive electrode connection terminal B+ and the first pin of the Zener diode D9, the third pin of the transistor Q5 is grounded, the resistor R52 is connected in parallel with the first and third pins of the transistor Q5, the first and third pins of the transistor Q5 are connected in parallel with the resistor R52, and a resistor R50 is connected in series between the first pin of the transistor Q5 and the resistor R52.

[0024] Furthermore, the second pin of the transistor Q5 is connected to the second pin of the Zener diode D8 , and the first pin of the Zener diode D8 is connected to the capacitor C26 and is grounded.

[0025] Specifically, the second pin of the transistor Q4 is connected to the first pin of the diode D8, the first and second pins of the transistor Q4 are connected in parallel with the resistor R49, the first pin of the transistor Q4 is connected to one end of the resistor R53, the other end of the resistor R53 is connected to the third pin of the transistor Q6, the second pin of the transistor Q6 is connected to one end of the capacitor C25, the other end of the capacitor C25 is connected to the detection terminal AD_CHK, the other end of the detection terminal AD_CHK is connected to one end of the resistor R47, and the other end of the resistor R47 is connected to the third pin of the transistor.

[0026] It is worth noting that the capacitor C25 and the resistor R51 are connected in parallel, and the second pin of the transistor Q6 is grounded.

[0027] Furthermore, a first pin of the transistor Q6 is connected to one end of the resistor R54, and the other end of the resistor R54 is connected to the auxiliary power supply terminal +5V.

[0028] The first pin of the transistor Q6 is connected to one end of the resistor R55 , and the other end of the resistor R55 is grounded.

[0029] In this embodiment, under normal working conditions, the startup is divided into two processes:

[0030] Process 1: Install the battery pack with the switch in the off mode and charge capacitor C26. The oscilloscope shows the following during the charging process: Figure 2 and Figure 3 The solid curve is because the switch is disconnected at this time, the auxiliary power supply part of the circuit is not powered, and the capacitor C25 is not charging. The oscilloscope shows Figure 2 and Figure 3 Dashed curve.

[0031] Process 2: Close the switch to start the tool, auxiliary power supply, +5V starts working, capacitor C26 has a discharge process, the oscilloscope shows as follows Figure 4 and Figure 5 The solid curve; capacitor C26 has a rapid charging and reaches a stable state, the oscilloscope shows Figure 4 and Figure 5 Dashed curve.

[0032] Furthermore, with the switch closed, insert the battery pack to start the tool:

[0033] The switch is in the closed state, the tool battery pack is installed, and "+5V" starts working slightly later than "B+". At this time, capacitor C26 is charged, and the oscilloscope shows Figure 6 and Figure 7 Solid curve; capacitor C25 is charged, and the oscilloscope shows Figure 6 and Figure 7 Middle dotted curve, at this time, you only need to disconnect the switch and then close the switch again to start the tool.

[0034] The present invention detects the change of the AD_CHK analog quantity at the capacitor C25 in the circuit through the MCU, which is used for switch status detection before the power tool is started, so as to achieve the effect of no output when the battery pack is installed when the tool's own switch is closed, thereby realizing the protection effect for the user.

[0035] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A switch closure power-on detection circuit, characterized in that: It includes a positive connection terminal B+, a negative connection terminal GND, a detection terminal AD_CHK, an auxiliary power supply terminal +5V, voltage-stabilizing diodes D8 and D9, transistors Q4, Q5, and Q6, capacitors C25 and C26, and resistors R46, R47, R49, R50, R51, R52, R53, R54, and R55. The positive connection terminal B+ is connected to the positive terminal of the battery pack, the negative connection terminal GND is connected to the negative terminal of the battery pack, and the detection terminal AD_CHK is connected to the MCU. The MCU is used to detect changes in the analog quantity at the detection terminal AD_CHK. The auxiliary power supply terminal +5V is connected to the auxiliary power supply circuit on the MCU and is also the operating voltage of the MCU. The positive electrode connection terminal B+ is connected to the first pin of the voltage-stabilizing diode D9, the second pin of the voltage-stabilizing diode D9 is connected to one end of the resistor R46, the other end of the resistor R46 is connected to the second pin of the transistor Q5, the third pin of the transistor Q5 is connected to one end of the resistor R52, the other end of the resistor R52 is connected to the positive electrode connection terminal B+ and the first pin of the voltage-stabilizing diode D9, the third pin of the transistor Q5 is grounded, the resistor R52 is connected in parallel with the first and third pins of the transistor Q5, the first and third pins of the transistor Q5 are connected in parallel with the resistor R52, and a resistor R50 is connected in series between the first pin of the transistor Q5 and the resistor R52; The second pin of the transistor Q5 is connected to the second pin of the voltage stabilizing diode D8, and the first pin of the voltage stabilizing diode D8 is connected to the capacitor C26 and grounded; The second pin of the transistor Q4 is connected to the first pin of the voltage-stabilizing diode D8, the resistor R49 is connected in parallel with the first and second pins of the transistor, the first pin of the transistor Q4 is connected to one end of the resistor R53, the other end of the resistor R53 is connected to the third pin of the transistor Q6, the second pin of the transistor Q6 is connected to one end of the capacitor C25, and the other end of the capacitor C25 is connected to the detection terminal AD_CHK.

2. The switch closed power-on detection circuit according to claim 1, characterized in that: The other end of the detection terminal AD_CHK is connected to one end of the resistor R47.

3. The switch closed power-on detection circuit according to claim 2, characterized in that: The other end of the resistor R47 is connected to the third pin of the transistor.

4. The switch closing power-on detection circuit according to claim 1, characterized in that: The capacitor C25 and the resistor R51 are connected in parallel, and the second pin of the transistor Q6 is grounded.

5. The switch closing power-on detection circuit according to claim 1, characterized in that: The first pin of the transistor Q6 is connected to one end of the resistor R54, and the other end of the resistor R54 is connected to the auxiliary power supply terminal +5V.

6. The switch closing power-on detection circuit according to claim 5, characterized in that: The first pin of the transistor Q6 is connected to one end of the resistor R55 , and the other end of the resistor R55 is grounded.

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