DC power supply overvoltage and undervoltage protection circuit and power supply equipment
The DC power supply protection circuit addresses the high cost and slow response issues of existing systems by using a single IO interface to trigger protection for both overvoltage and undervoltage, ensuring rapid and cost-effective protection.
Patent Information
- Application Number
- CN202422005700.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-19
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2034-08-19
AI Technical Summary
Existing DC power supply overvoltage or undervoltage detection circuits require a large amount of IO interface resources, resulting in a long response delay and the inability to trigger protection quickly, which is costly.
Using a DC power supply overvoltage and undervoltage protection circuit, by setting a target IO interface on the MCU protection unit, protection can be achieved by only one IO interface. The first and second output units output low-level signals when overvoltage or undervoltage are used. The MCU protection unit triggers protection actions based on the low-level signal, without distinguishing between specific overvoltage or undervoltage.
It realizes rapid trigger protection, reduces IO interface resource usage, simplifies circuit structure, reduces costs, and can immediately perform protection actions when overvoltage or undervoltage is detected.
Smart Images
Figure CN223109655U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electronic circuits, in particular to an overvoltage and undervoltage protection circuit for a DC power supply and a power supply device. Background Art
[0002] In order to prevent the port voltage of the DC output power supply from being overvoltage or undervoltage under abnormal conditions, resulting in abnormal damage to the power supply device itself and the devices and equipment loads connected thereto, relevant overvoltage and undervoltage detection circuits are usually set at the DC port on the output side. For example, in the related art, a resistor voltage division detection circuit branch is added to the DC port, and different resistor values are set to form different voltage division ratio parameters, so as to realize the overvoltage and undervoltage detection of the output voltage signal. If it is detected that the output voltage signal is determined to have overvoltage or undervoltage, a protection action needs to be performed on it. At present, in this case, it is usually necessary to specifically determine whether it is overvoltage or undervoltage before the protection can be triggered accordingly. In order to realize the determination of overvoltage and undervoltage conditions, a large number of IO interface resources need to be occupied in this process, and the overall cost is relatively high. Moreover, due to the long delay time in the response of a large number of IO interface resources, the protection cannot be triggered quickly. Summary of the Utility Model
[0003] The utility model aims to at least solve one of the technical problems in the related art to a certain extent. For this purpose, the utility model provides an overvoltage and undervoltage protection circuit for a DC power supply with controllable cost, simple structure and capable of quickly triggering protection.
[0004] In a first aspect, an embodiment of the utility model provides an overvoltage and undervoltage protection circuit for a DC power supply, including:
[0005] A first output unit, configured to output a low-level signal when the output voltage of the DC power supply is overvoltage;
[0006] A second output unit, configured to output a low-level signal when the output voltage of the DC power supply is undervoltage;
[0007] A first sampling unit, respectively connected to the output end of the first output unit and the output end of the second output unit, and the first sampling unit is configured to sample and obtain the low-level signal output by the first output unit or the second output unit;
[0008] An MCU protection unit, configured to connect to the DC power supply, the MCU protection unit sets a target IO interface, and the target IO interface is connected to the output end of the first sampling unit; when the target IO interface receives the low-level signal output by the first sampling unit, the MCU protection unit triggers overvoltage and undervoltage protection for the DC power supply.
[0009] Optionally, in an embodiment of the present invention, it further includes a second sampling unit for sampling the output voltage of the DC power supply. The MCU protection unit is provided with an AD interface, and the second sampling unit is respectively connected to the AD interface and the output terminal of the DC power supply; when the target IO interface receives the low-level signal output by the first sampling unit and the AD interface receives the voltage sampling result output by the second sampling unit, the MCU protection unit determines the overvoltage and undervoltage fault types of the DC power supply according to the voltage sampling result.
[0010] Optionally, in an embodiment of the present invention, the first output unit includes a first output element and a first diode for preventing reverse connection. The non-inverting input terminal of the first output element is used to access the overvoltage and undervoltage detection signal of the DC power supply, and the inverting input terminal of the first output element is used to access a preset high-level reference signal. The first output element is used to compare the overvoltage and undervoltage detection signal and the preset high-level reference signal to output a low-level signal when the output voltage of the DC power supply is overvoltage; the output terminal of the first output element is connected to the negative electrode of the first diode, and the positive electrode of the first diode is connected to the input terminal of the first sampling unit.
[0011] Optionally, in an embodiment of the present invention, the second output unit includes a second output element and a second diode for preventing reverse connection. The non-inverting input terminal of the second output element is used to access a preset low-level reference signal, and the inverting input terminal of the second output element is used to access the overvoltage and undervoltage detection signal of the DC power supply. The second output element is used to compare the preset low-level reference signal and the overvoltage and undervoltage detection signal to output a low-level signal when the output voltage of the DC power supply is undervoltage; the output terminal of the second output element is connected to the negative electrode of the second diode, and the positive electrode of the second diode is connected to the input terminal of the first sampling unit.
[0012] Optionally, in an embodiment of the present invention, the first sampling unit includes a sampling element, a first current-limiting resistor, and a second current-limiting resistor. The input terminal of the sampling element is respectively connected to the output terminal of the first output unit and the output terminal of the second output unit. The first current-limiting resistor is arranged between a preset first voltage source and the input terminal of the sampling element; the output terminal of the sampling element is connected to the target IO interface and is also connected to a preset second voltage source through the second current-limiting resistor.
[0013] Optionally, in an embodiment of the present invention, the first output element / second output element adopts an operational amplifier or a comparator.
[0014] Optionally, in an embodiment of the present invention, the sampling element is an optocoupler, an optoelectronic relay or a triode.
[0015] In a second aspect, an embodiment of the present invention further provides a power supply device, including the DC power overvoltage and undervoltage protection circuit as described in the first aspect.
[0016] The DC power overvoltage and undervoltage protection circuit and the power supply device proposed by the present invention, compared with the related prior art, by setting a target IO interface on the MCU protection unit, only one IO interface on the MCU protection unit is required to achieve protection, and the overall circuit structure is simple and the cost is controllable; when the target IO interface receives the low-level signal output by the first sampling unit, since the first sampling unit samples the low-level signal output by the first output unit in the overvoltage case or the second output unit in the undervoltage case, so whether it is overvoltage or undervoltage, as long as the target IO interface receives the low-level signal, it can be determined that there must be an overvoltage or undervoltage situation, so there is no need to separately distinguish between overvoltage and undervoltage, and thus the protection can be directly and quickly triggered. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic structural diagram of a DC power overvoltage and undervoltage protection circuit provided by an embodiment of the present invention;
[0018] Figure 2 is a circuit schematic diagram of a DC power overvoltage and undervoltage protection circuit provided by an embodiment of the present invention;
[0019] Figure 3 is a circuit schematic diagram of a DC power overvoltage and undervoltage protection circuit provided by another embodiment of the present invention;
[0020] Figure 4 is a circuit schematic diagram of a DC power overvoltage and undervoltage protection circuit provided by another embodiment of the present invention;
[0021] Figure 5 is a schematic structural diagram of a power supply device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.
[0023] It should be noted that although the functional modules are divided in the device schematic diagram, in some cases, they can be divided differently from the modules in the device.
[0024] Figure 1 The structural schematic diagram of the overvoltage and undervoltage protection circuit for a DC power supply provided by an embodiment of the present utility model.
[0025] As Figure 1 shown, the overvoltage and undervoltage protection circuit for the DC power supply 500 specifically includes, but is not limited to:
[0026] The first output unit 100 is used to output a low-level signal when the output voltage of the DC power supply 500 is overvoltage.
[0027] The second output unit 200 is used to output a low-level signal when the output voltage of the DC power supply 500 is undervoltage.
[0028] The first sampling unit 300 is respectively connected to the output end of the first output unit 100 and the output end of the second output unit 200. The first sampling unit 300 is used to sample and obtain the low-level signal output by the first output unit 100 or the second output unit 200.
[0029] The MCU protection unit 400 is used to connect to the DC power supply 500. The MCU protection unit 400 sets the target IO interface IO_1, and the target IO interface IO_1 is connected to the output end of the first sampling unit 300; when the target IO interface IO_1 receives the low-level signal output by the first sampling unit 300, the MCU protection unit 400 triggers overvoltage and undervoltage protection for the DC power supply 500.
[0030] It can be seen that, compared with the related prior art, by setting the target IO interface IO_1 on the MCU protection unit 400, only one IO interface on the MCU protection unit 400 is required to achieve protection, and the overall circuit structure is simple and the cost is controllable; when the target IO interface IO_1 receives the low-level signal output by the first sampling unit 300, since the first sampling unit 300 samples the low-level signal output by the first output unit 100 in the overvoltage case or the second output unit 200 in the undervoltage case, therefore, whether it is overvoltage or undervoltage, as long as the target IO interface IO_1 receives the low-level signal, it can be determined that there must be an overvoltage or undervoltage situation, so there is no need to separately distinguish whether it is specifically overvoltage or undervoltage, and thus the protection can be triggered directly and quickly.
[0031] It should be noted that the specific type, composition method, etc. of the MCU protection unit 400 can be various, which are not limited here. For example, referring to Figure 2, the MCU protection unit 400 can be, but is not limited to, an MCU. This MCU is integrated with a protection function and can trigger protection according to the IO interface signal / AD port signal. The MCU usually has a large number of IO interfaces for use. However, in this embodiment, the number of IO interfaces does not have to be set too many. Those skilled in the art can select the corresponding MCU according to the actual application scenario for setting. Or, the MCU provides basic functions and is combined with an external protection unit to form the MCU protection unit 400. Among them, the external protection unit is related prior art well-known to those skilled in the art and will not be elaborated here.
[0032] In one embodiment, as Figure 2 shown, the first output unit 100 includes a first output element A1 and a first diode D1 for preventing reverse connection. The non-inverting input terminal of the first output element A1 is used to access the overvoltage and undervoltage detection signal of the DC power supply 500, and the inverting input terminal of the first output element A1 is used to access a preset high-level reference signal. The first output element A1 is used to compare the overvoltage and undervoltage detection signal with the preset high-level reference signal to output a low-level signal when the output voltage of the DC power supply 500 is overvoltage; the output terminal of the first output element A1 is connected to the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected to the input terminal of the first sampling unit 300. It can be seen that the first output element A1 is used to simultaneously access the overvoltage and undervoltage detection signal of the DC power supply 500 and the preset high-level reference signal, so as to further compare the magnitude relationship between the overvoltage and undervoltage detection signal and the preset high-level reference signal. In this case, since the voltage value of the overvoltage and undervoltage detection signal is higher than the voltage value of the preset high-level reference signal, a low-level signal will be output. Among them, the first output element A1 can be, but is not limited to, an operational amplifier or a comparator.
[0033] In one embodiment, as Figure 2As shown, the second output unit 200 includes a second output component A2 and a second diode D2 for preventing reverse connection. The non-inverting input terminal of the second output component A2 is used to access a preset low-level reference signal, and the inverting input terminal of the second output component A2 is used to access the overvoltage and undervoltage detection signal of the DC power supply 500. The second output component A2 is used to compare the preset low-level reference signal and the overvoltage and undervoltage detection signal to output a low-level signal when the output voltage of the DC power supply 500 is undervoltage; the output terminal of the second output component A2 is connected to the negative electrode of the second diode D2, and the positive electrode of the second diode D2 is connected to the input terminal of the first sampling unit 300. It can be seen that the second output component A2 is used to simultaneously access the overvoltage and undervoltage detection signal of the DC power supply 500 and the preset low-level reference signal, so as to further compare the magnitude relationship between the overvoltage and undervoltage detection signal and the preset low-level reference signal. In this case, since the voltage value of the overvoltage and undervoltage detection signal is lower than the voltage value of the preset low-level reference signal, a low-level signal will be output. Among them, the second output component A2 can be, but is not limited to, an operational amplifier or a comparator.
[0034] It should be noted that the specific parameters of the preset high-level reference signal and the preset low-level reference signal can be set accordingly according to the actual application scenario, and there is no limitation here; the acquisition of the overvoltage and undervoltage detection signal is related to the existing technology in this field. For example, referring to Figure 3 , in this application scenario, it can be, but is not limited to, using an output detection circuit for detection. The output detection circuit is arranged between the DC port voltage of the DC power supply 500 and the overvoltage and undervoltage protection circuit of the DC power supply 500 in this embodiment. The output detection circuit uses a resistor voltage division method for detection. Figure 3 The output detection circuit shown in
[0035] is a combined type, that is, overvoltage and undervoltage are combined for sampling, and the output is combined in one circuit. It can also use different resistor voltage division circuits for separate sampling and separate detection and output. Figure 4As shown, the first sampling unit 300 includes a sampling element OP1, a first current-limiting resistor R1, and a second current-limiting resistor R2. The input end of the sampling element OP1 is respectively connected to the output end of the first output unit 100 and the output end of the second output unit 200. The first current-limiting resistor R1 is disposed between a preset first voltage source V1 and the input end of the sampling element OP1; the output end of the sampling element OP1 is connected to the target IO interface IO_1 and is also connected to a preset second voltage source V2 through the second current-limiting resistor R2. It can be seen that under the current-limiting effects of the first current-limiting resistor R1 and the second current-limiting resistor R2, since the input end of the sampling element OP1 is respectively connected to the output end of the first output unit 100 and the output end of the second output unit 200, when an overvoltage or undervoltage situation occurs, the sampling element OP1 can obtain a low-level signal through the output end of the first output unit 100 or the output end of the second output unit 200, and then directly transmit the low-level signal to the target IO interface IO_1. Among them, the preset first voltage source V1 and second voltage source V2 are used to provide a bias operating current for the sampling element OP1 and at the same time provide the required operating voltages for the first current-limiting resistor R1 and the second current-limiting resistor R2, and their parameters can be set by themselves and are not limited here; the sampling element OP1 can be but not limited to an optocoupler, an optoelectronic relay, or a triode. For example Figure 4 the shown sampling element OP1 adopts an isolation device, that is, an optocoupler, while Figure 3 the shown sampling element OP1 adopts a non-isolation device, that is, a MOSFET triode, and both are acceptable and are not limited here.
[0036] In one embodiment, as Figure 4 shown, the overvoltage and undervoltage protection circuit of the DC power supply 500 further includes a second sampling unit OP2 for sampling the output voltage of the DC power supply 500. The MCU protection unit 400 sets an AD interface AD_1, and the second sampling unit OP2 is respectively connected to the AD interface AD_1 and the output end of the DC power supply 500; when the target IO interface IO_1 receives the low-level signal output by the first sampling unit 300 and the AD interface AD_1 receives the voltage sampling result output by the second sampling unit OP2, the MCU protection unit 400 determines the overvoltage and undervoltage fault types of the DC power supply 500 according to the voltage sampling result.
[0037] It can be seen that through single-channel voltage sampling, overvoltage and undervoltage signals are combined on a single IO interface. For the MCU protection unit 400, after the corresponding IO signal quickly triggers a protection action, fast protection is achieved. Then, the AD sampling result of the power supply voltage is read, and based on the AD sampling result, it is determined whether it is an overvoltage or undervoltage fault, that is, slow reporting is achieved. Whether it is overvoltage or undervoltage, the protection logic is executed first, and then the fault information is reported, thereby achieving fast protection. This can reduce the time when the DC power supply 500 is damaged and play a better protection role. In particular, the multiplexing of multiple protection functions is achieved using fewer IO interface resources, streamlining the chip's IO interface resources, and at the same time reducing the number of relevant sampling devices, reducing the overall circuit cost. Refer to Figure 4 , the second sampling unit OP2 uses an operational amplifier or a comparator, and its non-inverting input terminal is used to connect the detected DC port voltage, which can be achieved by connecting the second sampling unit OP2 to the output detection circuit.
[0038] To better clarify the working principles of the above embodiments, the following is a detailed description based on Figure 4 the overvoltage and undervoltage protection circuit of the DC power supply 500 shown.
[0039] As Figure 4 shown, the first output element A1 and the second output element A2 are both operational amplifiers, and the sampling element OP1 is an optocoupler; when an overvoltage or undervoltage signal is detected on the output side, the detected overvoltage and undervoltage detection signal Vo_VP is compared with the two operational amplifiers respectively. When overvoltage or undervoltage occurs, the corresponding action is triggered, and a low-level signal is output. As a result, the primary diode of the optocoupler conducts, and the secondary triode of the optocoupler also conducts synchronously, causing the Vce voltage of the optocoupler to be pulled low, presenting a low level. As a result, the target IO interface IO_1 of the MCU protection unit 400 also receives this low-level fault signal, and by responding to this signal, a fast protection function can be achieved.
[0040] The specific working mechanism is as follows:
[0041] When the output voltage port voltage Vdc is within the rated range, the Vo_VP voltage is less than the preset high-level reference signal REF_H voltage, and the first output element A1 outputs a high level at this time; similarly, when the Vo_VP voltage is greater than the preset low-level reference signal REF_L voltage, the second output element A2 also outputs a high level at this time. At this time, the diode on the primary side of the optocoupler does not conduct, and the target IO interface IO_1 is pulled up to a high level through the first current-limiting resistor R1;
[0042] When the DC side voltage is overvoltage, the Vo_VP voltage is higher than the REF_H voltage, and the first output element A1 will output a low level; when the DC side voltage is undervoltage, the Vo_VP voltage is less than the REF_L voltage, and the second output element A2 will output a low level; if any one of the first output element A1 and the second output element A2 outputs a low level, the primary side of the photocoupler will be turned on, and then the Vce of the photocoupler will be pulled down, and a low level signal will be given to the target IO interface IO_1 to achieve fast overvoltage and undervoltage protection.
[0043] In addition, if Figure 5 As shown, an embodiment of the utility model further discloses a power supply device 800, including the DC power supply overvoltage and undervoltage protection circuit 700 as shown in any of the above embodiments.
[0044] The power supply device 800 provided in the embodiment of the utility model corresponds to the DC power supply overvoltage and undervoltage protection circuit 700 and belongs to the same inventive concept. Therefore, the power supply device 800 also has the embodiments and beneficial technical effects of the corresponding DC power supply overvoltage and undervoltage protection circuit 700. Since the embodiments and beneficial technical effects of the DC power supply overvoltage and undervoltage protection circuit 700 have been described in detail above, the embodiments and beneficial technical effects of the corresponding power supply device 800 will not be repeated here.
[0045] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.
Claims
1. A DC power overvoltage and undervoltage protection circuit, characterized in that, Including: A first output unit, configured to output a low-level signal when the output voltage of the DC power supply is overvoltage; A second output unit, configured to output a low-level signal when the output voltage of the DC power supply is undervoltage; A first sampling unit, respectively connected to the output end of the first output unit and the output end of the second output unit, and the first sampling unit is configured to sample and obtain the low-level signal output by the first output unit or the second output unit; An MCU protection unit, configured to be connected to the DC power supply, the MCU protection unit is provided with a target IO interface, and the target IO interface is connected to the output end of the first sampling unit; when the target IO interface receives the low-level signal output by the first sampling unit, the MCU protection unit triggers overvoltage and undervoltage protection for the DC power supply.
2. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 1, wherein, It further includes a second sampling unit for sampling the output voltage of the DC power supply, the MCU protection unit is provided with an AD interface, and the second sampling unit is respectively connected to the AD interface and the output end of the DC power supply; when the target IO interface receives the low-level signal output by the first sampling unit and the AD interface receives the voltage sampling result output by the second sampling unit, the MCU protection unit determines the overvoltage and undervoltage fault type of the DC power supply according to the voltage sampling result.
3. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 1, characterized in that The first output unit includes a first output element and a first diode for preventing reverse connection. The non-inverting input terminal of the first output element is used to access the overvoltage and undervoltage detection signal of the DC power supply, and the inverting input terminal of the first output element is used to access a preset high-level reference signal. The first output element is configured to compare the overvoltage and undervoltage detection signal and the preset high-level reference signal to output a low-level signal when the output voltage of the DC power supply is overvoltage; the output end of the first output element is connected to the negative electrode of the first diode, and the positive electrode of the first diode is connected to the input end of the first sampling unit.
4. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 3, characterized in that, The second output unit includes a second output element and a second diode for preventing reverse connection. The non-inverting input terminal of the second output element is used to access a preset low-level reference signal, and the inverting input terminal of the second output element is used to access the overvoltage and undervoltage detection signal of the DC power supply. The second output element is configured to compare the preset low-level reference signal and the overvoltage and undervoltage detection signal to output a low-level signal when the output voltage of the DC power supply is undervoltage; the output end of the second output element is connected to the negative electrode of the second diode, and the positive electrode of the second diode is connected to the input end of the first sampling unit.
5. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 1, wherein The first sampling unit includes a sampling element, a first current-limiting resistor and a second current-limiting resistor. The input end of the sampling element is respectively connected to the output end of the first output unit and the output end of the second output unit. The first current-limiting resistor is arranged between a preset first voltage source and the input end of the sampling element; the output end of the sampling element is connected to the target IO interface and is also connected to a preset second voltage source through the second current-limiting resistor.
6. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 4, characterized in that, The first output element / second output element employs an operational amplifier or a comparator.
7. The overvoltage and undervoltage protection circuit for a DC power supply according to claim 5, characterized in that, The sampling element employs an optocoupler, an optoelectronic relay or a triode.
8. A power supply device, characterized in that, Comprising: The DC power supply overvoltage undervoltage protection circuit according to any one of claims 1 to 7.