Power failure detection circuit and electronic equipment
By introducing a combination of energy storage branch and switching branch in the power-down detection circuit, the voltage of the energy storage branch drives the optical coupler to conduct and disconnect, the problem of excessive power consumption in the prior art is solved, and the power consumption is reduced while maintaining the detection function normally.
Patent Information
- Application Number
- CN202421985562.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2034-08-15
AI Technical Summary
When the existing AC power supply power-down detection circuit is implemented through the optocoupler, the resistance value should not be too large, resulting in too high power consumption, and the inability to drive the optocoupler to conduct, resulting in abnormal function, or the resistance value is small, resulting in too high power consumption.
The combination of the first switching branch, the resistor branch, the energy storage branch, the second switching branch and the third switching branch is adopted, and the optical coupler is driven to conduct and disconnect the voltage of the energy storage branch to realize power-down detection, and the resistance branch is set to a larger value to reduce power consumption.
While maintaining the power-down detection function normally, power consumption is reduced through a larger resistor branch, avoiding the problem of excessive power consumption.
Smart Images
Figure CN223229731U_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the technical field of electronic circuits, and in particular to a power-off detection circuit and an electronic device. Background Art
[0002] A brownout detection circuit monitors when the power supply voltage drops below a certain threshold. When the power supply voltage falls below the preset threshold, the brownout detection circuit triggers appropriate actions, such as resetting the system, saving data, or switching to a backup power source.
[0003] At present, the most common power-off detection circuit for detecting AC power is a circuit implemented by an optocoupler. Specifically, the AC power is input into the optocoupler after passing through a resistor. When the AC power is in the positive half cycle, the output optocoupler is turned on and outputs a signal to the controller, so that the controller determines whether the power has been lost based on the received signal.
[0004] However, since the AC power directly acts on the optocoupler after passing through the resistor, the resistance of the resistor should not be too large, otherwise it will cause the optocoupler to fail to turn on and cause malfunction. However, if the resistance of the resistor is too small, the power consumption will be too high. Utility Model Content
[0005] Embodiments of the present application provide a power-off detection circuit and an electronic device, which can reduce power consumption while maintaining a normal power-off detection function.
[0006] In a first aspect, an embodiment of the present application provides a power-off detection circuit, comprising:
[0007] a first switch branch, connected to a live wire of an AC power source, and configured to be turned on when a voltage of the AC power source is greater than a first preset voltage, and to be turned off when the voltage of the AC power source is less than or equal to the first preset voltage;
[0008] a resistance branch and an energy storage branch, wherein the energy storage branch is connected to the first switch branch through the resistance branch, and the energy storage branch is configured to be charged by the AC power supply when the first switch branch is turned on, and to discharge when the first switch branch is turned off;
[0009] a second switch branch, connected to the energy storage branch, configured to be turned on when the voltage of the energy storage branch is greater than a second preset voltage, and to be turned off when the voltage of the energy storage branch is less than or equal to the second preset voltage;
[0010] A third switch branch and a controller, wherein the third switch branch is connected between the second switch branch and the controller, and the third switch branch includes an optocoupler. The third switch branch is configured such that when the second switch branch is turned on, the optocoupler is turned on in response to the voltage on the energy storage branch, and outputs a first level to the controller so that the controller determines that the AC power supply has not been powered off. The third switch branch is configured such that when the second switch branch is turned off, the optocoupler is turned off, and outputs a second level to the controller so that the controller determines that the AC power supply has been powered off.
[0011] In one or more embodiments, the first switch branch includes a diode;
[0012] The anode of the diode is connected to the live wire of the AC power supply, and the cathode of the diode is connected to the resistance branch.
[0013] In one or more embodiments, the resistance branch includes a first resistor;
[0014] The first end of the first resistor is connected to the first switch branch, and the second end of the first resistor is connected to the energy storage branch and the second switch branch respectively.
[0015] In one or more embodiments, the energy storage branch includes a first capacitor;
[0016] A first end of the first capacitor is connected to the resistance branch and the second switch branch respectively, and a second end of the first capacitor is connected to the neutral line of the AC power supply.
[0017] In one or more embodiments, the second switch branch includes a trigger diode;
[0018] The first end of the trigger diode is connected to the energy storage branch and the resistance branch respectively, and the second end of the trigger diode is connected to the third switch branch.
[0019] In one or more embodiments, the third switch branch further includes a second resistor, a third resistor, and a fourth resistor;
[0020] The second resistor is connected between the second switch branch and the anode of the light emitting device of the optocoupler, the cathode of the light emitting device of the optocoupler is connected to the neutral line of the AC power supply, the first end of the light receiver of the optocoupler is respectively connected to the first end of the third resistor and the first end of the fourth resistor, the second end of the third resistor is connected to the first power supply, the second end of the fourth resistor is connected to the controller, and the second end of the light receiver of the optocoupler is grounded.
[0021] In a second aspect, an embodiment of the present application provides an electronic device, comprising the power-off detection circuit as described above.
[0022] The beneficial effects of the present application are as follows: the power-off detection circuit of the embodiment of the present application includes a first switch branch, a resistor branch, an energy storage branch, a second switch branch, a third switch branch and a controller. When the voltage of the AC power supply is greater than the first preset voltage, the first switch branch is turned on, and the energy storage branch is charged by the AC power supply until the voltage of the energy storage branch is greater than the second preset voltage. The second switch branch is turned on, and then the optocoupler is turned on in response to the voltage on the energy storage branch, and the third switch branch outputs a first level to the controller, so that the controller determines that the AC power supply has not been powered off. When the voltage of the AC power supply is less than or equal to the first preset voltage, the first switch branch is disconnected, and the energy storage branch is discharged until the voltage of the energy storage branch is less than or equal to the second preset voltage. The second switch branch is disconnected, and then the optocoupler is disconnected, and the third switch branch outputs a second level to the controller, so that the controller determines that the AC power supply has been powered off. At this point, the process of determining whether the AC power supply has been powered off is realized. In the above process, since the energy storage branch is charged first and then the optocoupler is driven based on the voltage of the energy storage branch, even if the resistance of the resistance branch is set to a larger value, as long as the energy storage branch can be charged, the optocoupler can be driven, and the power-off detection function will not be abnormal. By setting the resistance of the resistance branch to a larger value, the purpose of reducing power consumption can be achieved, thereby achieving the goal of reducing power consumption while maintaining the normal power-off detection function. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] One or more embodiments are exemplarily described by the figures in the accompanying drawings, which are not intended to limit the embodiments. Elements with the same reference numerals in the drawings represent similar elements.
[0024] Figure 1 Schematic diagram of a block diagram of a power-off detection circuit provided in an embodiment of the present application;
[0025] Figure 2 is with Figure 1 The block diagram shown corresponds to the circuit structure schematic diagram. DETAILED DESCRIPTION
[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and in detail below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of them. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.
[0027] It should be noted that, when an element is referred to as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.
[0028] In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as there is no structural conflict between them.
[0029] Please refer to Figure 1 , Figure 1 Schematic diagram of the block diagram of the power failure detection circuit provided in the embodiment of the present application. Figure 1 As shown, the power failure detection circuit 100 includes a first switch branch 10, a resistor branch 20, an energy storage branch 30, a second switch branch 40, a third switch branch 50 and a controller 60. The third switch branch 50 includes an optocoupler U1.
[0030] The first switch branch 10 is connected to the live wire L of the AC power source 200, the energy storage branch 30 is connected to the first switch branch 10 via the resistor branch 20, the second switch branch 40 is connected to the energy storage branch 30, and the third switch branch 50 is connected between the second switch branch 40 and the controller 60. Specifically, the first end of the first switch branch 10 is connected to the live wire L of the input power source 200, the second end of the first switch branch 10 is connected to the first end of the resistor branch 20, the second end of the resistor branch 20 is connected to the first end of the energy storage branch and the first end of the second switch branch 40, respectively, the second end of the energy storage branch 30 is connected to the second end of the optocoupler U1 and the neutral wire N of the AC power source, respectively, the second end of the second switch branch 40 is connected to the first end of the optocoupler U1, and the third end of the optocoupler U1 is connected to the controller 60. In some embodiments, the AC power source 200 is a mains supply.
[0031] Specifically, the first switch branch 10 is configured to turn on when the voltage of the AC power source 200 is greater than a first preset voltage, and to turn off when the voltage of the AC power source 200 is less than or equal to the first preset voltage. The energy storage branch 30 is configured to be charged by the AC power source 200 when the first switch branch 10 is turned on, and to discharge when the first switch branch 10 is turned off. The second switch branch 40 is configured to turn on when the voltage of the energy storage branch 30 is greater than a second preset voltage, and to turn off when the voltage of the energy storage branch 30 is less than or equal to the second preset voltage. The third switch branch 50 is configured such that when the second switch branch 40 is turned on, the optocoupler U1 turns on in response to the voltage on the energy storage branch 30 and outputs a first voltage level to the controller 60, allowing the controller 60 to determine that the AC power source 200 has not lost power. The third switch branch 50 is configured such that when the second switch branch 40 is turned off, the optocoupler U1 turns off and outputs a second voltage level to the controller 60, allowing the controller 60 to determine that the AC power source 200 has lost power.
[0032] The first preset voltage and the second preset voltage can be set based on actual application scenarios, and the embodiments of the present application do not impose specific limitations on this. For example, in some embodiments, the first preset voltage can be set based on the characteristics of the first switch branch 10, such as the first preset voltage being set to the minimum voltage that drives the first switch branch 10 to conduct. For another example, in some embodiments, the second preset voltage can be set based on the characteristics of the second switch branch 40, such as the second preset voltage being set to the minimum voltage that drives the second switch branch 40 to conduct. The first level and the second level are different levels. When the first level is high, the second level is low; when the first level is low, the second level is high.
[0033] In actual applications, when the voltage of the AC power source 200 is greater than a first preset voltage, the first switch branch 10 is turned on, and the AC power source 200 charges the energy storage branch 30 through the first switch branch 10 and the resistor branch 20. The second switch branch 40 is turned on until the voltage of the energy storage branch 30 is greater than a second preset voltage. Subsequently, the voltage on the energy storage branch 30 acts on the optocoupler U1 through the second switch branch 40, causing the optocoupler U1 to turn on in response to the voltage on the energy storage branch 30. The third switch branch 50 outputs a first voltage level to the controller 60, allowing the controller 60 to determine that the AC power source 200 is not powered off.
[0034] When the voltage of the AC power source 200 is less than or equal to the first preset voltage, the first switch branch 10 is disconnected, and the energy storage branch 30 discharges until the voltage of the energy storage branch 30 is less than or equal to the second preset voltage, at which point the second switch branch 40 is disconnected. Subsequently, the connection between the energy storage branch 30 and the optocoupler U1 is disconnected, the optocoupler U1 is disconnected, and the third switch branch 50 outputs a second voltage level to the controller 60, allowing the controller 60 to determine that the AC power source 200 has lost power.
[0035] At this point, the process of determining whether the AC power supply 200 has lost power has been completed. In the above process, since the energy storage branch 30 is first charged, and then the optocoupler U1 is driven based on the voltage of the energy storage branch 30, even if the resistance of the resistor branch 20 is set to a large value, as long as the energy storage branch 30 can be charged, the optocoupler U1 will be driven, and the power failure detection function will not malfunction. By setting the resistance of the resistor branch 20 to a large value, the purpose of reducing power consumption can be achieved. In summary, the power failure detection function is maintained normally while reducing power consumption.
[0036] Please refer to Figure 2 , Figure 2 An example is shown with Figure 1 A circuit structure corresponding to the block diagram shown in FIG. Figure 2 As shown, the first switching branch 10 includes a diode D1 .
[0037] The anode of the diode D1 is connected to the live wire L of the AC power source 200 , and the cathode of the diode D1 is connected to the resistance branch 20 .
[0038] Specifically, when the voltage of the AC power source 200 is greater than the forward voltage drop of the diode D1 (typically 0.7V), the diode D1 is forward-conducting, and the corresponding first switch branch 10 is turned on. Conversely, when the voltage of the AC power source 200 is less than or equal to the forward voltage drop of the diode D1, the diode D1 is reverse-conducting, and the corresponding first switch branch 10 is turned off. At this time, the forward voltage drop of the diode D1 is the first preset voltage.
[0039] It should be noted that, in other embodiments, the first switch branch 10 may also include other switching devices, such as an NMOS tube. By short-circuiting the gate and source of the NMOS tube and connecting it to the live wire L of the AC power supply 200, and connecting the drain of the NMOS tube to the resistance branch 20, the function achieved is the same as that of the diode D1.
[0040] In this embodiment, the resistance branch 20 includes a first resistor R1 .
[0041] The first end of the first resistor R1 is connected to the first switch branch 10 , and the second end of the first resistor R1 is connected to the energy storage branch 30 and the second switch branch 40 respectively.
[0042] Specifically, the first resistor R1 is used for current limiting.
[0043] In this embodiment, the energy storage branch 30 includes a first capacitor C1.
[0044] A first end of the first capacitor C1 is connected to the resistor branch 20 and the second switch branch 40 respectively, and a second end of the first capacitor C1 is connected to the neutral line N of the AC power source 200 .
[0045] Specifically, when the diode D1 is forward-conducted, the AC power supply 200 charges the first capacitor C1 through the diode D1 and the first resistor R1; when the diode D1 is reverse-conducted, the first capacitor C1 is discharged.
[0046] In this embodiment, the second switching branch 40 includes a trigger diode D2 .
[0047] The first end of the trigger diode D2 is connected to the energy storage branch 30 and the resistance branch 20 respectively, and the second end of the trigger diode D2 is connected to the third switch branch 50 .
[0048] Specifically, when the voltage on the first capacitor C1 reaches the trigger voltage of the trigger diode D2, the trigger diode D2 turns on, and the corresponding second switch branch 40 turns on. The voltage on the first capacitor C1 can act on the optocoupler U1 through the trigger diode D2 and the second resistor R2, so that the light emitter of the optocoupler U1 is energized and the light receiver of the optocoupler U1 is turned on, and the corresponding optocoupler U1 is turned on. Conversely, when the voltage on the first capacitor C1 does not reach the trigger voltage of the trigger diode D2, the trigger diode D2 remains off, and the corresponding second switch branch 40 is disconnected. The light emitter of the optocoupler U1 is not energized, the light receiver of the optocoupler U1 remains disconnected, and the corresponding optocoupler U1 is disconnected.
[0049] In this embodiment, the third switch branch 50 further includes a second resistor R2 , a third resistor R3 , and a fourth resistor R4 .
[0050] Among them, the second resistor R2 is connected between the second switch branch 40 and the anode of the light emitter of the optocoupler U1, the cathode of the light emitter of the optocoupler U1 is connected to the neutral line N of the AC power supply 200, the first end of the light receiver of the optocoupler U1 is respectively connected to the first end of the third resistor R3 and the first end of the fourth resistor R4, the second end of the third resistor R3 is connected to the first power supply V1, the second end of the fourth resistor R4 is connected to the controller 60, and the second end of the light receiver of the optocoupler U1 is grounded GND.
[0051] Specifically, the second resistor R2 and the fourth resistor R4 are used for current limiting. The third resistor R3 is a pull-up resistor.
[0052] The following Figure 2 The principle of the circuit structure shown is explained again.
[0053] When the voltage of the AC power supply 200 is greater than the forward conduction voltage drop of the diode D1, the diode D1 conducts forward, and the AC power supply 200 charges the first capacitor C1 through the diode D1 and the first resistor R1. This continues until the voltage of the first capacitor C1 is greater than the trigger voltage of the trigger diode D2, causing the trigger diode D2 to conduct. Subsequently, the voltage on the first capacitor C1 acts on the optocoupler U1 through the trigger diode D2 and the second resistor R2, energizing the light emitter of the optocoupler U1 and turning on the light receiver of the optocoupler U1. The controller 60 connects to the ground GND of the light receiver of the optocoupler U1 through the fourth resistor R4. This corresponds to the controller 60 receiving a low level (i.e., in this embodiment, the first level is taken as the low level), and also corresponds to the third switch branch 50 outputting a low level to the controller 60. Based on the received low level, the controller 60 can then determine that the AC power supply 200 is not powered off.
[0054] When the voltage of the AC power source 200 is less than or equal to the forward voltage drop of diode D1, diode D1 is disconnected, and first capacitor C1 discharges until the voltage of first capacitor C1 is less than or equal to a second predetermined voltage, triggering diode D2 to disconnect. Subsequently, the connection between first capacitor C1 and optocoupler U1 is disconnected, the light emitter of optocoupler U1 is de-energized, and the light receiver of optocoupler U1 remains disconnected. The voltage of first power source V1 is input to controller 60 through third resistor R3 and fourth resistor R4, corresponding to controller 60 receiving a high level (i.e., in this embodiment, the second level is assumed to be a high level), and corresponding to third switch branch 50 outputting a high level to controller 60. Based on the received high level, controller 60 can then determine that the AC power source 200 has lost power.
[0055] It can be understood that there are two situations in which the voltage of the AC power supply 200 is less than or equal to the forward conduction voltage drop of the diode D1. One is that when the voltage of the AC power supply 200 has not yet increased to be greater than the forward conduction voltage drop of the diode D1, the diode D1 remains disconnected and the first capacitor C1 is usually discharged. That is, there is no voltage on the first capacitor C1, then the first capacitor C1 is neither discharged nor charged, the voltage of the first capacitor C1 is less than the second preset voltage, and the diode D2 is triggered to be disconnected. The other is that when the voltage of the AC power supply 200 decreases from greater than the forward conduction voltage drop of the diode D1 to less than or equal to the forward conduction voltage drop of the diode D1, the diode D1 is disconnected, the first capacitor C1 is discharged, and the voltage of the first capacitor C1 is less than or equal to the second preset voltage, and the diode D2 is triggered to be disconnected.
[0056] At this point, the process of determining whether the AC power supply 200 has lost power is completed. In the above process, since the first capacitor C1 is charged first, and then the optocoupler U1 is driven based on the voltage of the first capacitor C1, even if the resistance value of the first resistor R1 is set to a large value, since the first capacitor C1 can be kept charged, the voltage on the first capacitor C1 will increase. Then, the voltage of the first capacitor C1 will inevitably be able to drive the optocoupler U1, and the power failure detection function will not be abnormal. By setting the resistance value of the first resistor R1 to a large value, the purpose of reducing power consumption can be achieved. In summary, it is achieved that power consumption is reduced while maintaining the normal power failure detection function.
[0057] An embodiment of the present application further provides an electronic device, which includes the power-off detection circuit 100 in any embodiment of the present application.
[0058] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.
[0059] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them. Based on the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, and the steps may be implemented in any order. A person skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some of the technical features may be replaced by equivalents. However, such modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A power-off detection circuit, characterized in that: include: a first switch branch, connected to a live wire of an AC power source, and configured to be turned on when a voltage of the AC power source is greater than a first preset voltage, and to be turned off when the voltage of the AC power source is less than or equal to the first preset voltage; a resistance branch and an energy storage branch, wherein the energy storage branch is connected to the first switch branch through the resistance branch, and the energy storage branch is configured to be charged by the AC power supply when the first switch branch is turned on, and to discharge when the first switch branch is turned off; a second switch branch, connected to the energy storage branch, configured to be turned on when the voltage of the energy storage branch is greater than a second preset voltage, and to be turned off when the voltage of the energy storage branch is less than or equal to the second preset voltage; A third switch branch and a controller, wherein the third switch branch is connected between the second switch branch and the controller, and the third switch branch includes an optocoupler. The third switch branch is configured such that when the second switch branch is turned on, the optocoupler is turned on in response to the voltage on the energy storage branch, and outputs a first level to the controller so that the controller determines that the AC power supply has not been powered off. The third switch branch is configured such that when the second switch branch is turned off, the optocoupler is turned off, and outputs a second level to the controller so that the controller determines that the AC power supply has been powered off.
2. The power-off detection circuit according to claim 1, wherein: The first switch branch includes a diode; The anode of the diode is connected to the live wire of the AC power supply, and the cathode of the diode is connected to the resistance branch.
3. The power-off detection circuit according to claim 1, wherein: The resistance branch includes a first resistor; The first end of the first resistor is connected to the first switch branch, and the second end of the first resistor is connected to the energy storage branch and the second switch branch respectively.
4. The power-off detection circuit according to claim 1, wherein: The energy storage branch includes a first capacitor; A first end of the first capacitor is connected to the resistance branch and the second switch branch respectively, and a second end of the first capacitor is connected to the neutral line of the AC power supply.
5. The power-off detection circuit according to claim 1, wherein: The second switch branch includes a trigger diode; The first end of the trigger diode is connected to the energy storage branch and the resistance branch respectively, and the second end of the trigger diode is connected to the third switch branch.
6. The power-off detection circuit according to claim 1, wherein: The third switch branch further includes a second resistor, a third resistor and a fourth resistor; The second resistor is connected between the second switch branch and the anode of the light emitting device of the optocoupler, the cathode of the light emitting device of the optocoupler is connected to the neutral line of the AC power supply, the first end of the light receiver of the optocoupler is respectively connected to the first end of the third resistor and the first end of the fourth resistor, the second end of the third resistor is connected to the first power supply, the second end of the fourth resistor is connected to the controller, and the second end of the light receiver of the optocoupler is grounded.
7. An electronic device, characterized in that: The method comprises the power-off detection circuit according to any one of claims 1 to 6.