Power supply connection state detection circuit, electronic device and electronic device protection method

Abstract

The present invention relates to a power supply access state detection circuit, an electronic device and an electronic device protection method, which comprises: a power supply input terminal for connecting a power supply input, a power supply output terminal for connecting an execution circuit, a switch, a charging circuit and a comparison unit; the first end of the switch is connected to the positive pole of the power supply input terminal, and the second end of the switch is connected to the power supply output terminal; the first end of the charging circuit is connected to the first end of the switch, the second end of the charging circuit is connected to the negative pole of the power supply input terminal, and the third end of the charging circuit is connected to the first input end of the comparison unit; the second input end of the comparison unit is used to receive a reference voltage, the reference voltage is less than the preset charging voltage of the charging circuit and greater than zero, and the output end of the comparison unit outputs a level signal when the power supply output end is connected to the power supply input end. The implementation of the present invention can identify the state of the switch when the power supply is connected to ensure safe use.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply detection, and more specifically, to a power supply access status detection circuit, an electronic device and an electronic device protection method. Background Art

[0002] When many electronic devices are in use, there are strict requirements for the order of power connection and switch on to ensure safety during use. However, for many circuits, the power connection and switch on states cannot be distinguished. When the switch is on, when the power is connected, the internal circuit will be powered on. In fact, at this time, the working state of connecting the power when the switch is on is an abnormal operation, which will bring danger to the operator. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a power connection status detection circuit, an electronic device and an electronic device protection method in view of the above-mentioned technical defects of the prior art.

[0004] The technical solution adopted by the present invention to solve the technical problem is: constructing a power access state detection circuit, including: a power input terminal for connecting to a power input, a power output terminal for connecting to an execution circuit, a switch, a charging circuit and a comparison unit;

[0005] The first end of the switch is connected to the positive electrode of the power input end, and the second end of the switch is connected to the power output end;

[0006] The first end of the charging loop is connected to the first end of the switch, the second end of the charging loop is connected to the negative electrode of the power input end, and the third end of the charging loop is connected to the first input end of the comparison unit;

[0007] The second input end of the comparison unit is used to receive a reference voltage, which is less than the preset charging voltage of the charging circuit and greater than zero. The output end of the comparison unit outputs a level signal when the power output end is connected to the power input end.

[0008] Preferably, the charging circuit includes a first voltage divider unit and a charging element, the first end of the first voltage divider unit is connected to the first end of the switch, the second end of the first voltage divider unit is connected to the negative electrode of the power input end, and the third end of the first voltage divider unit is connected to the first input end of the comparison unit; the charging element is connected to the second end and the third end of the first voltage divider unit.

[0009] Preferably, the first voltage dividing unit includes a resistor R1 and a resistor R3 connected in series, the resistor R1 is connected to the first end of the switch, the resistor R3 is connected to the negative electrode of the power input end, and the series node of the resistor R1 and the resistor R3 is connected to the first input end of the comparison unit.

[0010] Preferably, the charging element comprises a capacitor C1, and the capacitor C1 is connected in parallel with the resistor R3.

[0011] Preferably, it also includes a second voltage dividing unit, a first end of the second voltage dividing unit is connected to the second end of the switch, a second end of the second voltage dividing unit is connected to the negative electrode of the power input end, and a third end of the second voltage dividing unit is connected to the second input end of the comparison unit.

[0012] Preferably, the second voltage dividing unit includes a resistor R2 and a resistor R4 connected in series, the resistor R2 is connected to the second end of the switch, the resistor R4 is connected to the negative electrode of the power input end, and the series node of the resistor R2 and the resistor R4 is connected to the second input end of the comparison unit; the resistance ratio of the resistor R1 to the resistor R3 is smaller than the resistance ratio of the resistor R2 to the resistor R4.

[0013] Preferably, the resistance value of the resistor R1 is equal to the resistance value of the resistor R2.

[0014] The comparison unit includes a comparator U1, wherein the first input end of the comparison unit is the inverting input end of the comparator U1, and the second input end of the comparison unit is the non-inverting input end of the comparator U1; or the first input end of the comparison unit is the non-inverting input end of the comparator U1, and the second input end of the comparison unit is the inverting input end of the comparator U1.

[0015] Preferably, the power supply connection status detection circuit of the present invention further includes a control unit;

[0016] The control unit is connected to the output end of the comparison unit and the execution circuit, and is used for receiving the level signal and starting the execution circuit when the level signal is at a constant level.

[0017] The present invention also constructs an electronic device, comprising any one of the power supply access status detection circuits described above.

[0018] The present invention also constructs an electronic device protection method, based on any one of the power supply access status detection circuits described above, comprising:

[0019] When the power input is connected, the level signal of the output end of the comparison unit is obtained to confirm whether the level signal is a constant level. If so, the execution circuit connected to the power output end is started normally, otherwise, the execution circuit is not started.

[0020] The power supply connection state detection circuit, electronic device and electronic device protection method of the present invention have the following beneficial effects: the state of the switch when the power supply is connected can be identified to ensure safe use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0022] Figure 1 It is a logic block diagram of a first embodiment of a power supply connection state detection circuit of the present invention;

[0023] Figure 2 is a logic block diagram of a second embodiment of a power supply connection state detection circuit of the present invention;

[0024] Figure 3 is a circuit schematic diagram of a second embodiment of a power supply connection state detection circuit of the present invention;

[0025] Figure 4 is a logic block diagram of a third embodiment of a power supply connection state detection circuit of the present invention;

[0026] Figure 5 is a circuit schematic diagram of a third embodiment of a power supply connection state detection circuit of the present invention;

[0027] Figure 6 is a logic block diagram of a fourth embodiment of a power supply connection state detection circuit of the present invention;

[0028] Figure 7 is a circuit schematic diagram of a fourth embodiment of a power supply connection state detection circuit of the present invention;

[0029] Figure 8 It is a circuit principle diagram of the fifth embodiment of the power supply connection state detection circuit of the present invention. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0031] like Figure 1As shown, in the first embodiment of the power access state detection circuit of the present invention, it includes: a power input terminal 10 for connecting the power input, a power output terminal 30 for connecting the execution circuit, and a switch 20, a charging circuit 40 and a comparison unit 50; the first end of the switch 20 is connected to the positive electrode of the power input terminal 10, and the second end of the switch 20 is connected to the power output terminal 30; the first end of the charging circuit 40 is connected to the first end of the switch 20, the second end of the charging circuit 40 is connected to the negative electrode of the power input terminal 10, and the third end of the charging circuit 40 is connected to the first input end of the comparison unit 50; the second input end of the comparison unit 50 is used to receive a reference voltage, the reference voltage is less than the preset charging voltage of the charging circuit 40 and greater than zero, and the output end of the comparison unit 50 outputs a level signal when the power output terminal 30 is connected to the power input terminal 10. Specifically, the charging circuit 40 is set between the power input terminal 10 and the switch 20, and when the power input terminal 10 has a power input, the charging circuit 40 starts charging and outputs the charging voltage at the third end of the charging circuit 40. When the power input is connected, the switch 20 is in the open state, that is, the switch 20 is closed after the power input is connected. When the power input is connected, the charging circuit 40 is charged. Before the switch 20 is closed, the third end of the charging circuit 40 will output a stable preset charging voltage. After the switch 20 is closed, the power output end 30 is connected to the power input end 10. The power input can supply power to the comparison unit 50 through the closed switch 20 and the power output end 30. The comparison unit 50 starts to work. At this time, it can also be understood that the detection circuit starts to work. At this time, the first input end of the comparison unit 50 has the preset charging voltage of the charging circuit 40, and the second input end of the comparison unit 50 is provided with a reference voltage. The comparison unit 50 outputs a first level signal according to the comparison result of the reference voltage and the preset charging voltage. When the switch 20 is in the closed state before the power input is connected, then when the power input is connected, the charging circuit 40 starts to charge, and the charging voltage outputted from its third end is a changing process, that is, the input voltage of the first input end of the comparison unit 50 increases from zero to the preset charging voltage, that is, the output end of the comparison unit 52 will have a level signal changing process during the charging process of the charging circuit 40. At the same time, the switch 20 is closed, and the power input supplies power to the comparison unit 50 through the switch 20 and the power output terminal 30. At this time, the reference voltage of the second input terminal of the comparison unit 50 does not change. At this time, when the reference voltage is set to a certain value lower than the preset charging voltage, the charging change process of the charging circuit 40 can be captured according to the comparison result of the comparison unit 50. The specific process is that when the charging voltage of the charging circuit 40 is lower than the reference voltage, the comparison unit 50 outputs a second level signal according to the comparison result. When the charging circuit 40 continues to charge until the charging is completed, the charging voltage of the charging circuit 40, that is, the output voltage of the third terminal, is the preset charging voltage, that is, higher than the reference voltage, the comparison unit 50 outputs a first level signal according to the comparison result.At this time, it can be determined whether the power input is connected when the switch 20 is closed or the power input is connected when the switch 20 is open, based on whether the comparison unit 50 continuously outputs the first level signal, thereby completing the determination of the power connection state.

[0032] Optional, such as Figure 2 In the illustrated embodiment, the charging circuit 40 includes a first voltage dividing unit 41 and a charging element 42, wherein the first end of the first voltage dividing unit 41 is connected to the first end of the switch 20, the second end of the first voltage dividing unit 41 is connected to the negative electrode of the power input terminal 10, and the third end of the first voltage dividing unit 41 is connected to the first input terminal of the comparison unit 50; the charging element 42 is connected to the second end and the third end of the first voltage dividing unit 41. Specifically, the preset charging voltage of the charging circuit 40 can be set by the first voltage dividing unit 41, that is, during the charging process of the charging element 42, the voltage across the two ends of the charging element 42 is the voltage divided output terminal of the first voltage dividing unit 41, that is, the voltage divided at the third end.

[0033] Further, such as Figure 3 As shown, the first voltage dividing unit 41 includes a resistor R1 and a resistor R3 connected in series, the resistor R1 is connected to the first end of the switch 20, the resistor R3 is connected to the negative electrode of the power input terminal 10, and the series node of the resistor R1 and the resistor R3 is connected to the first input end of the comparison unit 50. Specifically, the first voltage dividing unit 41 uses the resistor R1 and the resistor R3 connected in series, which has the advantage of a simple structure.

[0034] Furthermore, the charging element 42 includes a capacitor C1, which is connected in parallel with a resistor R3. Specifically, based on the above, the charging element 42 can be a capacitor C1, which is charged through a resistor R1 when the power input terminal 10 is connected to the power supply, and is no longer charged when the voltage of the capacitor C1 is equal to the divided voltage of the resistor R3. That is, a preset charging voltage is obtained at the input terminal of the capacitor.

[0035] Further, such as Figure 4In the illustrated embodiment, the power connection state detection circuit of the present invention further includes a second voltage divider unit 60, a first end of the second voltage divider unit 60 is connected to the second end of the switch 20, a second end of the second voltage divider unit 60 is connected to the negative electrode of the power input terminal 10, and a third end of the second voltage divider unit 60 is connected to the second input terminal of the comparison unit 50. Specifically, the reference voltage of the second input terminal of the comparison unit 50 can also be provided by the power input of the power input terminal 10. The specific principle is that when the switch 20 is closed and the power input passes through, the voltage divider voltage of the second voltage divider unit 60, that is, the output voltage of the third end, is the reference voltage. If the power input is already in the connection state when the switch 20 is closed, then the voltage of the charging circuit 40 at the first input terminal of the comparison unit 50 is higher than the reference voltage, and it directly outputs the corresponding first level signal. If the power input is not connected when the switch 20 is closed, then during the power connection process, according to the change of the charging voltage of the charging circuit 40, the comparison unit 50 will still output a change process from the second power signal to the first level signal at its output terminal according to the relationship between the charging voltage and the reference voltage.

[0036] Further, such as Figure 5 As shown, the second voltage dividing unit 60 includes a resistor R2 and a resistor R4 connected in series, the resistor R2 is connected to the second end of the switch 20, the resistor R4 is connected to the negative electrode of the power input terminal 10, and the resistor R2 and the resistor R4 are connected in series at a node connected to the second input end of the comparison unit 50; the resistance ratio of the resistor R1 to the resistor R3 is less than the resistance ratio of the resistor R2 to the resistor R4. Specifically, the second voltage dividing unit 60 can also use resistors connected in series, which divide the voltage by the resistor R2 and the resistor R4 connected in series to obtain a reference voltage. In order to make the reference voltage less than the preset charging voltage of the charging circuit 40, the resistance ratio of the first voltage dividing unit 41 and the second voltage dividing unit 60 must satisfy that the resistance ratio of the resistor R1 to the resistor R3 is less than the resistance ratio of the resistor R2 to the resistor R4.

[0037] Furthermore, the resistance value of the resistor R1 is equal to the resistance value of the resistor R2. Specifically, in actual circuit design, as long as the resistance values ​​of the resistors R1 and R2 are equal, at this time, as long as the resistance value of the resistor R4 is set to be smaller than the resistance value of the resistor R3, a voltage divider circuit that meets the requirements can be simply designed.

[0038] Further, such as Figure 3 and Figure 5As shown, the comparison unit 50 includes a comparator U1, the first input end of the comparison unit 50 is the inverting input end of the comparator U1, and the second input end of the comparison unit 50 is the non-inverting input end of the comparator U1; or the first input end of the comparison unit 50 is the non-inverting input end of the comparator U1, and the second input end of the comparison unit 50 is the inverting input end of the comparator U1. Specifically, the comparison unit 50 uses a comparator chip U1, the third end of the charging circuit 40 is connected to the inverting input end of the comparator U1, and the reference voltage is provided by the non-inverting input end of the comparator U1. It should be noted that in some embodiments, the reference voltage of the non-inverting input end of the comparator U1 can be provided by the comparator U1 itself, and the chip of the comparator U1 that can be selected here can be selected according to needs. Here, it is described in detail according to its specific connection relationship. When the first input terminal of the comparison unit 50 is the inverting input terminal of the comparator U1, and the second input terminal of the comparison unit 50 is the non-inverting input terminal of the comparator U1, that is, the charging voltage of the charging circuit 40 is input by the inverting terminal of the comparator U1, and the reference voltage is input by the non-inverting terminal of the comparator U1, then according to the working principle of the comparator U1, when the charging voltage of the charging circuit 40 is lower than the reference voltage, the first level signal output by the comparator U1 is a high level signal, and when the charging voltage of the charging circuit 40 reaches a preset charging voltage higher than the reference voltage, the second level signal output by the output terminal of the comparator U1 is a low level signal. According to the above description, when the power output terminal and the power input terminal are connected, when the level signal at the output terminal of the comparator U1 changes from a low level signal to a high level signal, it is understood as a change level rather than a constant level, that is, it can be determined that the power input is connected when the switch 20 is closed. As long as the level signal at the output terminal of the comparator U1 is a constant high level signal, it is understood as a constant level, and the power input is determined to be connected before the switch 20 is closed. In another embodiment, when the first input terminal of the comparison unit 50 is the non-inverting input terminal of the comparator U1, the second input terminal of the comparison unit 50 is the inverting input terminal of the comparator U1. That is, the charging voltage of the charging circuit 40 is input by the non-inverting terminal of the comparator U1, and the reference voltage is input by the inverting terminal of the comparator U1. Then, according to the working principle of the comparator U1, when the charging voltage of the charging circuit 40 is lower than the reference voltage, the first level signal output by the comparator U1 is a low level signal. When the charging voltage of the charging circuit 40 reaches a preset charging voltage higher than the reference voltage, the second level signal output by the output terminal of the comparator U1 is a high level signal. According to the above description, when the power output terminal and the power input terminal are connected, when the level signal at the output terminal of the comparator U1 changes from a high level signal to a low level signal, it is understood as a change level rather than a constant level, that is, it can be determined that the power input is connected when the switch 20 is closed. As long as the level signal at the output terminal of the comparator U1 is a constant low level signal, it is understood as a constant level, and the power input is determined to be connected before the switch 20 is closed.It can also be understood that the comparator U1 here can be a voltage comparator. It can also be understood that the working power supply of the comparator U1 is the power output of the power output terminal 30 after conversion.

[0039] In addition, if Figure 3 and Figure 5 As shown, the switch 20 includes a switch device S1, which can be a normally open or normally closed switch.

[0040] like Figure 6 In the illustrated embodiment, the power supply connection state detection circuit of the present invention further includes a control unit 70; the control unit 70 is connected to the output end of the comparison unit 50 and the execution circuit, and is used to receive the level signal and start the execution circuit when the level signal is a constant level. Specifically, according to the above description, when the power input is turned on, when the output level signal of the comparison unit 50 changes from a high level signal to a low level signal or from a low level signal to a high level signal, that is, it is understood as a change level rather than a constant level, it is determined that the power input is connected when the switch 20 is closed, and this is an abnormal working state. The control unit 70 does not start the execution circuit connected to the power input end 10. Here, the execution circuit can also be understood as a working circuit. Only when the level signal at the output end of the comparison unit 50 is a constant low level signal or a constant high level signal, it is understood as a constant level, and it is determined that the power input is connected when the switch 20 is disconnected, that is, the card closing occurs after the power is connected. This is a normal working state, and the control unit 70 can normally start the subsequent execution circuit to work normally.

[0041] Further, such as Figure 7 As shown, the control unit 70 includes an MCU chip U6, and the power supply of the MCU chip U6 is the power output of the power output terminal 30 after conversion. Figure 8 As shown, the execution circuit may include a motor drive circuit, and the control signal output by the MCU chip U6 controls the on or off of the motor drive circuit to perform corresponding work.

[0042] In addition, an electronic device of the present invention includes any one of the above power connection state detection circuits. Specifically, the above power connection state detection circuit can be set in the electronic device to determine the power connection state of the electronic device to ensure the safety of the electronic device. For example, a power saw, etc.

[0043] Another electronic device protection method of the present invention is based on any one of the above power supply connection status detection circuits, comprising:

[0044] When the power input is connected, the level signal of the output end of the comparison unit 50 is obtained to confirm whether the level signal is a constant level. If so, the execution circuit connected to the power output terminal 30 is started normally. If not, the execution circuit is not started. Specifically, referring to the above description, the power connection state corresponding to the electronic device is obtained by the power connection state detection circuit described above, and the safe working method of the electronic device is set according to the power connection state. The specific process is referred to the above description and will not be repeated here. When the execution circuit is not started, an alarm message of abnormal power connection state can be generated to prompt corrective measures, such as disconnecting and then reclosing the switch 20 to make it enter a normal working state.

[0045] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A power supply access status detection circuit, It is characterized in that include: A power input terminal for connecting a power input, a power output terminal for connecting an execution circuit, a switch, a charging circuit and a comparison unit; The first end of the switch is connected to the positive electrode of the power input end, and the second end of the switch is connected to the power output end; The first end of the charging loop is connected to the first end of the switch, the second end of the charging loop is connected to the negative electrode of the power input end, and the third end of the charging loop is connected to the first input end of the comparison unit; The second input terminal of the comparison unit is used to receive a reference voltage, the reference voltage is less than the preset charging voltage of the charging circuit and greater than zero, and the output terminal of the comparison unit outputs a level signal when the power output terminal and the power input terminal are connected; The charging circuit includes a first voltage dividing unit and a charging element, wherein a first end of the first voltage dividing unit is connected to a first end of the switch, a second end of the first voltage dividing unit is connected to a negative electrode of the power input end, and a third end of the first voltage dividing unit is connected to a first input end of the comparison unit; the charging element is connected to the second end and the third end of the first voltage dividing unit; The comparison unit includes a comparator U1, wherein the first input end of the comparison unit is the inverting input end of the comparator U1, and the second input end of the comparison unit is the non-inverting input end of the comparator U1; or the first input end of the comparison unit is the non-inverting input end of the comparator U1, and the second input end of the comparison unit is the inverting input end of the comparator U1.

2. The power supply status detection circuit according to claim 1, Features: The first voltage dividing unit includes a resistor R1 and a resistor R3 connected in series, the resistor R1 is connected to the first end of the switch, the resistor R3 is connected to the negative electrode of the power input end, and the series node of the resistor R1 and the resistor R3 is connected to the first input end of the comparison unit.

3. The power supply connection status detection circuit according to claim 2, It is characterized in that The charging element includes a capacitor C1 , and the capacitor C1 is connected in parallel with the resistor R3 .

4. The power supply connection status detection circuit according to claim 2, It is characterized in that It also includes a second voltage dividing unit, a first end of the second voltage dividing unit is connected to the second end of the switch, a second end of the second voltage dividing unit is connected to the negative electrode of the power input end, and a third end of the second voltage dividing unit is connected to the second input end of the comparison unit.

5. The power supply connection status detection circuit according to claim 4, It is characterized in that The second voltage dividing unit includes a resistor R2 and a resistor R4 connected in series, the resistor R2 is connected to the second end of the switch, the resistor R4 is connected to the negative electrode of the power input end, and the series node of the resistor R2 and the resistor R4 is connected to the second input end of the comparison unit; the resistance ratio of the resistor R1 to the resistor R3 is less than the resistance ratio of the resistor R2 to the resistor R4.

6. The power supply connection status detection circuit according to claim 5, It is characterized in that The resistance value of the resistor R1 is equal to the resistance value of the resistor R2.

7. The power supply status detection circuit according to any one of claims 1 to 6, It is characterized in that Also includes a control unit; The control unit is connected to the output end of the comparison unit and the execution circuit, and is used for receiving the level signal and starting the execution circuit when the level signal is at a constant level.

8. An electronic device, It is characterized in that It comprises a power supply connection status detection circuit as described in any one of claims 1 to 7.

9. A method for protecting an electronic device, It is characterized in that A power supply connection status detection circuit according to any one of claims 1 to 7, comprising: When the power input is connected, the level signal of the output end of the comparison unit is obtained to confirm whether the level signal is a constant level. If so, the execution circuit connected to the power output end is started normally, otherwise, the execution circuit is not started.

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