Power-on protection circuit and electronic equipment

Abstract

The embodiment of the utility model relates to the field of power-off protection, and discloses a power-on protection circuit and electronic equipment. The power-on protection circuit comprises a zero-cross detection module, a control module and a power supply module, the zero-crossing detection circuit comprises a zero-crossing signal detection node and a switch arranged between the zero-crossing signal detection node and the power supply module. The control module is connected with the zero-crossing detection module, and the control module is used for controlling the electronic equipment to start if the zero-crossing signal detection node does not detect the zero-crossing signal and the switch state is switched into a closed state after power-on; and if the zero-crossing signal detection node detects a zero-crossing signal, controlling the electronic equipment to stop starting until the switch state is switched to the off state and switched to the on state again, and controlling the electronic equipment to start. Therefore, the reliability of a power failure detection result is improved.

Description

Technical Field

[0001] This utility model relates to the field of power failure protection, and in particular to a power-on protection circuit and electronic device. Background Technology

[0002] Electronic devices typically include power-on protection circuits. These circuits prevent energy waste or accidents caused by sudden surges in current when the electronic device experiences a sudden power outage and the switch is forgotten to be turned off. Current power-on protection circuits usually utilize the principle of the time delay in the charging and discharging of capacitors, determining whether to activate power-on protection by detecting the potential difference across the capacitor.

[0003] The inventors discovered at least the following problems with power-on protection circuits implemented using the capacitor principle: Due to energy consumption considerations, current circuit construction typically uses AC-DC modules to reduce power consumption. Because AC-DC chips inherently require a soft-start time, the capacitor charging process in the power-on protection circuit is completed within this soft-start time. This results in the inability to detect the potential difference, preventing timely power-on protection and rendering the circuit ineffective. Utility Model Content

[0004] The purpose of this utility model embodiment is to provide a power-on protection circuit and electronic device, which comprehensively determines whether the current circuit is in a power-off state by using the detection results of the zero-crossing signal and the detection results of the switch state, thereby improving the reliability of the power-off detection results and providing safety protection for the electronic device when power is restored.

[0005] To address the aforementioned technical problems, embodiments of this utility model provide a power-on protection circuit, comprising: a zero-crossing detection module, a control module, and a power supply module; the zero-crossing detection circuit includes: a zero-crossing signal detection node, and a switch disposed between the zero-crossing signal detection node and the power supply module; the control module is connected to the zero-crossing detection module, and the control module is configured to, after power-on, if the zero-crossing signal detection node does not detect a zero-crossing signal, switch the state of the switch to a closed state, and then control the electronic device to start; if the zero-crossing signal detection node detects a zero-crossing signal, control the electronic device to pause starting until the switch state switches to an open state and then switches back to a closed state, and then control the electronic device to start.

[0006] An embodiment of this utility model provides an electronic device, including the power-on protection circuit described above.

[0007] Compared with related technologies, this utility model embodiment utilizes the detection results detected by the zero-crossing signal detection node and the detection results of the state of the switch set between the zero-crossing signal detection node and the power module to comprehensively determine whether the current circuit is in a power-off state, thereby improving the reliability of the power-off detection results. After power-on, if the switch state switches to the closed state after the zero-crossing signal detection node does not detect a zero-crossing signal, the electronic device is controlled to start; if the zero-crossing signal detection node detects a zero-crossing signal, the electronic device is controlled to pause starting until the switch state switches to the open state and then switches to the closed state again, after which the electronic device is controlled to start, so as to ensure safety protection for the electronic device when power is restored.

[0008] In addition, the zero-crossing detection circuit also includes a voltage divider module; the voltage divider module is disposed between the switch and the zero-crossing signal detection node, and is used to divide the output voltage of the power supply module to the zero-crossing signal detection node.

[0009] In addition, the voltage divider module consists of several first resistors connected in series.

[0010] In addition, the resistance values ​​of the several first resistors connected in series are all between 510KΩ and 1MΩ.

[0011] In addition, the zero-crossing detection circuit also includes a filtering module; the filtering module is connected to the zero-crossing signal detection node and is located at the end of the zero-crossing signal detection node away from the power supply module, and is used to filter and denoise the electrical signal passing through the zero-crossing signal detection node.

[0012] In addition, the filter module consists of a capacitor and a second resistor connected in parallel.

[0013] In addition, a number of first resistors are connected in series between the switch and the zero-crossing signal detection node; the resistance value of the second resistor is determined based on the sum of the resistances of the number of first resistors connected in series and the output voltage of the power module to the zero-crossing signal detection node.

[0014] In addition, the electronic devices are powered by AC power.

[0015] In addition, the control module is also used to control the indicator light to display a preset prompt color if the zero-crossing signal detection node detects a zero-crossing signal after power-on. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1This is a schematic diagram of a power-on protection circuit according to the first embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a power-on protection circuit according to the second embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of a power-on protection circuit according to the third embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of a power-on protection circuit according to the fourth embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of a power-on protection circuit according to the fifth embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the electrical signal detected by the zero-crossing signal detection node in the case of power failure of a power-on protection circuit according to the present invention;

[0023] Figure 7 This is a schematic diagram of the electrical signal detected by the zero-crossing signal detection node under energized conditions in a power-on protection circuit according to the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to enable the reader to better understand this utility model. However, the technical solutions claimed by this utility model can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0025] The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this utility model. The various embodiments can be combined with or referenced by each other without contradiction.

[0026] The first embodiment of this utility model relates to a power-on protection circuit, such as... Figure 1As shown, the system includes: a zero-crossing detection module, a control module, and a power supply module. The zero-crossing detection circuit includes: a zero-crossing signal detection node TP1, and a switch that connects the zero-crossing signal detection node TP1 and the power supply module. The control module is connected to the zero-crossing detection module and the power supply module. After power-on, if the zero-crossing signal detection node TP1 does not detect a zero-crossing signal and the switch switches to the closed state, the control module controls the electronic device to start. If the zero-crossing signal detection node TP1 detects a zero-crossing signal, it means that the switch was still in the closed state after power-off, and therefore, a zero-crossing signal can be detected after power-on. To ensure circuit safety, the electronic device needs to be paused from starting. A preset warning color (e.g., red) can be displayed on an indicator light to alert personnel of any abnormal equipment operation. The electronic device will only start after the switch is detected to switch to the open state and then back to the closed state.

[0027] Compared with related technologies, this utility model embodiment utilizes the detection results detected by the zero-crossing signal detection node and the detection results of the state of the switch set between the zero-crossing signal detection node and the power module to comprehensively determine whether the current circuit is in a power-off state, thereby improving the reliability of the power-off detection results. After power-on, if the switch state switches to the closed state after the zero-crossing signal detection node does not detect a zero-crossing signal, the electronic device is controlled to start; if the zero-crossing signal detection node detects a zero-crossing signal, the electronic device is controlled to pause starting until the switch state switches to the open state and then switches to the closed state again, after which the electronic device is controlled to start, so as to ensure safety protection for the electronic device when power is restored.

[0028] In addition, the zero-crossing detection module, control module, and power supply module are all connected to the live wire L. The control module performs power-off protection after detecting that the electronic device is in a non-started state, detects the zero-crossing signal at the zero-crossing signal detection node TP1, and detects the on / off state of the switch. When the electronic device is in normal operating condition, power-off protection is not required, and therefore, it is unnecessary to detect the zero-crossing signal at the zero-crossing signal detection node TP1 or the switch state, thus saving energy.

[0029] The second embodiment of this utility model relates to a power-on protection circuit, such as... Figure 2As shown, the zero-crossing detection circuit also includes a voltage divider module. The voltage divider module is located between the switch and the zero-crossing signal detection node. It is used to divide the output voltage from the power module to the zero-crossing signal detection node TP1, or to limit the current flowing downstream of the voltage divider module. This prevents the zero-crossing signal detection node TP1 from being directly subjected to high voltage, which could damage the detection device. It can also enable the zero-crossing signal detection node TP1 to detect a suitable voltage value. For example, by connecting suitable resistors in series to form a voltage divider module, the zero-crossing signal detection node TP1 can detect a voltage change from a voltage greater than 3V to a voltage less than 2V as a zero-crossing signal.

[0030] The voltage divider module consists of several first resistors connected in series. The resistance values ​​of these first resistors are all between 510KΩ and 1MΩ. The first resistor is a 1206 resistor, meaning its package size is 0.12 inches × 0.06 inches × 0.02 inches (3.2 mm × 1.6 mm × 0.5 mm). The power rating of the first resistor is typically 0.125 watts or 0.25 watts. The resistance values ​​of the multiple first resistors connected in series can be set to the same value or different values ​​depending on the specific requirements.

[0031] The third embodiment of this utility model relates to a power-on protection circuit, such as... Figure 3 As shown, the zero-crossing detection circuit also includes a filtering module. The filtering module is connected to the zero-crossing signal detection node and is located at the end of the zero-crossing signal detection node furthest from the power supply module. It is used to filter and denoise the electrical signal passing through the zero-crossing signal detection node to prevent noise signals from being captured at the zero-crossing signal detection node TP1, thus avoiding errors in the detection results. The filtering module consists of a capacitor and a second resistor connected in parallel.

[0032] The fourth embodiment of this utility model relates to a power-on protection circuit, such as... Figure 4 As shown, the zero-crossing detection circuit includes the aforementioned voltage divider module and filter module. Several first resistors are connected in series between the switch and the zero-crossing signal detection node. The resistance value of the second resistor is determined based on the sum of the resistances of the several first resistors connected in series and the output voltage from the power supply module to the zero-crossing signal detection node, ensuring that the voltage signal detected at the zero-crossing signal detection node TP1 fluctuates within a fixed range. Therefore, the presence of a zero-crossing signal at the zero-crossing signal detection node TP1 can be analyzed based on the detected voltage value changes. The fluctuation range of the voltage signal detected by the zero-crossing signal detection node TP1 can typically be set between 3V and 5V. The specifications of the components in the voltage divider module and filter module can be, for example... Figure 4 The resistance of the two first resistors shown is 510kΩ, the capacitance is 100pF, the resistance of the second resistor is 300KΩ, and the downstream output of the filter module is -5V.

[0033] The fifth embodiment of this utility model relates to a power-on protection circuit, such as... Figure 5 As shown, the control module includes: a motor M, a drive module connected to the motor M for driving the motor M, a microcontroller unit (MCU) for controlling the drive module, and a power supply module connected to the MCU, which provides operating voltage to the MCU. After the MCU analyzes the detection results from the zero-crossing signal detection node and the detection results from the state of the switch set between the zero-crossing signal detection node and the power supply module, if it determines that the electronic device needs to be started, it controls the motor M to start through the drive module.

[0034] In addition, the curve of the electrical signal detected by the zero-crossing signal detection node TP1 changing with time is as follows: Figures 6 to 7 As shown, Figure 6 This represents the electrical signal detected by the zero-crossing signal detection node under power failure conditions. At this time, the electrical signal has a fixed value and its value will not change. Figure 7 The zero-crossing signal detection node detects the electrical signal when the power is on. Since the electronic device is powered by AC, the waveform of the electrical signal changes over time as a rectangular wave. The zero-crossing signal can be detected at the falling edge and rising edge of the rectangular wave.

[0035] An embodiment of this utility model provides an electronic device, including the aforementioned power-on protection circuit. The electronic device can be an edge trimmer or an angle grinder, and the power-on protection circuit is integrated into the edge trimmer or angle grinder. An indicator light is used to provide an abnormal indication in the event of a power-on malfunction.

[0036] Compared with related technologies, the electronic device provided in this embodiment of the present invention is equipped with the power-on protection circuit provided in the aforementioned embodiments. Therefore, it also has the technical effects provided in the aforementioned embodiments, which will not be elaborated here.

[0037] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A power-on protection circuit, characterized by, The application relates to an electronic device power-on protection circuit. The zero-crossing detection circuit comprises a zero-crossing signal detection node and a switch arranged between the zero-crossing signal detection node and the power module. The control module is connected with the zero-crossing detection module, and is used for controlling the electronic device to start if the switch state is switched to the closed state after power-on and no zero-crossing signal is detected by the zero-crossing signal detection node; and controlling the electronic device to suspend starting if the zero-crossing signal detection node detects a zero-crossing signal, until the switch state is switched to the open state and then switched to the closed state again, and then controlling the electronic device to start. The zero-crossing detection circuit further comprises a voltage dividing module.

2. The power-on protection circuit of claim 1, wherein, The voltage dividing module is arranged between the switch and the zero-crossing signal detection node, and is used for dividing the output voltage of the power module output to the zero-crossing signal detection node. The voltage dividing module is composed of a plurality of first resistors in series.

3. The power-on protection circuit of claim 2, wherein, The resistance values of the plurality of first resistors in series are all between 510KΩ and 1MΩ.

4. The power-on protection circuit of claim 3, wherein, The zero-crossing detection circuit further comprises a filter module.

5. The power-on protection circuit of claim 1, wherein, The filter module is connected with the zero-crossing signal detection node, and is arranged at the end of the zero-crossing signal detection node away from the power module, and is used for filtering and denoising the electric signal passing through the zero-crossing signal detection node. The filter module is composed of a capacitor and a second resistor in parallel.

6. The power-on protection circuit of claim 5, wherein, The switch and the zero-crossing signal detection node are connected with a plurality of first resistors in series; and the resistance value of the second resistor is determined based on the sum of the resistances of the plurality of first resistors in series and the output voltage of the power module output to the zero-crossing signal detection node.

7. The power-on protection circuit of claim 6, wherein, The electronic device is powered by alternating current.

8. The power-on protection circuit of claim 1, wherein, The control module is further used for controlling an indicator light to display a preset prompt color if the zero-crossing signal detection node detects a zero-crossing signal after power-on.

9. The power-on protection circuit of claim 1, wherein, The application relates to an electronic device power-on protection circuit.

10. An electronic device, comprising: The application relates to an electronic device power-on protection circuit. ​

Images