Two-path voltage comparison circuit
By combining the comparator circuit, power supply circuit, and isolation circuit, and using an optocoupler to determine the voltage magnitude, the problems of component redundancy and poor accuracy in traditional voltage comparison circuits are solved, achieving low-cost and high-precision voltage comparison.
Patent Information
- Application Number
- CN202511692326.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-01-20
AI Technical Summary
Traditional two-channel voltage comparison circuits suffer from component redundancy, high cost, poor accuracy, and are prone to malfunction, making them difficult to integrate and achieve high-precision judgment.
A voltage acquisition module and an optocoupler are used, combining a comparator circuit, a power supply circuit, and an isolation circuit. The voltage magnitude is determined by the conduction state of the optocoupler, and the detection accuracy is adjusted by the optocoupler and a resistor.
It achieves a simple, low-cost, and high-precision voltage comparison, reduces the number of components, improves detection accuracy, and prevents malfunctions, making it suitable for high-voltage environments.
Smart Images
Figure CN121367484A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of circuit design, and particularly relates to a two-way voltage comparison circuit. BACKGROUND
[0002] As a core module in electronic systems, voltage comparison circuits are widely used in power management, signal processing, industrial control and other fields. The core function of the voltage comparison circuit is to compare the difference between two input voltages and output a logic level signal to realize the interaction between analog and digital signals. However, the traditional two-way voltage comparison circuit as shown in FIG. 1 has the following defects: Figure 1 1. Component redundancy, high cost; the traditional voltage comparison circuit usually relies on multiple discrete components to build, resulting in high circuit complexity, large board area, and is not conducive to integration into other application circuits; 2. The higher the comparison voltage of the traditional voltage comparison circuit, the worse the precision; (for example: the power supply voltage is 300V, even if a 1% precision resistor is used, the maximum error is > 6V, the detection precision: 6V / 300 = 2%); 3. The traditional voltage comparison circuit is prone to misoperation when the voltage fluctuates; if the split resistance is set to prevent misoperation, it will produce a larger error and cannot judge the voltage with higher precision. SUMMARY
[0003] The present application aims to at least solve the technical problems existing in the prior art, and provides a two-way voltage comparison circuit.
[0004] The two-way voltage comparison circuit provided by the present application comprises a voltage acquisition module and an optoelectronic coupler, The voltage acquisition module comprises a first diode and a second diode, and the anode of the first diode is connected with the output end of the first power supply; The anode of the second diode is connected with the output end of the second power supply, and the cathode of the second diode is connected with the first input end of the optoelectronic coupler; The cathode of the first diode is connected with the second input end of the optoelectronic coupler; When the voltage input by the first input end of the optoelectronic coupler is greater than the voltage input by the second input end of the optoelectronic coupler, the optoelectronic coupler is turned on.
[0005] By adopting the technical scheme, the two-way voltage comparison circuit can judge the magnitude of the first power supply output voltage and the second power supply output voltage according to the state of the photoelectric coupler: when the voltage output by the second power supply is greater than the voltage output by the first power supply, the photoelectric coupler is turned on; when the voltage output by the second power supply is less than or equal to the voltage output by the first power supply, the photoelectric coupler is turned off; thus, the high and low of the first power supply output voltage and the second power supply output voltage can be clearly judged; the comparator circuit, the power supply circuit and the isolation circuit are combined, compared with the traditional comparison circuit, the number of elements used is small, the circuit is simple, and it is easier to integrate; in addition, the detection precision of the two-way voltage comparison circuit is determined by the turn-on voltage of the photoelectric coupler and the second resistor, so as to facilitate the designer to control the detection precision of the two-way voltage comparison circuit, and simplify the circuit structure while ensuring the high detection precision of the two-way voltage comparison circuit.
[0006] Optionally, the voltage acquisition module further comprises a voltage stabilizing diode, an anode of the voltage stabilizing diode is connected with a cathode of the first diode, and a cathode of the voltage stabilizing diode is connected with a cathode of the second diode.
[0007] By adopting the technical scheme, the first diode, the second diode and the voltage stabilizing diode can constitute a protection circuit, which can reduce the possibility of circuit damage caused by reverse current.
[0008] Optionally, the cathode of the first diode is connected with the ground through a first resistor, and the cathode of the second diode is connected with a first input end of the photoelectric coupler through a second resistor.
[0009] By adopting the technical scheme, when the voltage output by the second power supply is greater than the voltage output by the first power supply, the working path of the circuit is: the output end of the second power supply, the second diode, the second resistor, the photoelectric coupler, the first resistor to the ground, and the photoelectric coupler is turned on; when the voltage output by the second power supply is less than or equal to the voltage output by the first power supply, the working path of the circuit is: the output end of the first power supply, the first diode, the first resistor to the ground, and the photoelectric coupler is turned off.
[0010] Optionally, the resistance value of the first resistor is adjustable, and the resistance value of the second resistor is adjustable.
[0011] By adopting the technical scheme, the resistance value of the first resistor and / or the second resistor can be adjusted according to the range of the first power supply output voltage and the second power supply output voltage, so as to limit the current passing through the photoelectric coupler, thereby ensuring the reliable work of the two-way voltage comparison circuit.
[0012] Optionally, the number of the first resistors is set to be multiple, and the multiple first resistors are arranged in series or in parallel.
[0013] By adopting the technical scheme, in the high-voltage circuit, a single resistor needs to bear a high voltage, and the power consumption P can also be very large, which can cause the resistor to overheat or even burn out; by replacing the single first resistor R1 with an equivalent resistor composed of a plurality of first resistors in series (or a plurality of first resistors in parallel), the total power consumption can be shared, which can better protect the circuit.
[0014] Optionally, a first capacitor is connected in parallel between the first input of the optocoupler and the second input of the optocoupler.
[0015] By adopting the technical scheme, when the ripple voltage of the first power supply and the second power supply is large, the interference signal generated is filtered by the first capacitor, and under the fixed deviation of the optocoupler, the misoperation can be effectively prevented.
[0016] In summary, the present application has the following beneficial technical effects: The two-way voltage comparison circuit provided by the present application can judge the size of the first power supply output voltage and the second power supply output voltage according to the state of the optocoupler: when the voltage output by the second power supply is greater than the voltage output by the first power supply, the optocoupler is turned on; when the voltage output by the second power supply is less than or equal to the voltage output by the first power supply, the optocoupler is turned off; thus the high and low of the first power supply and the second power supply output voltage can be clearly judged; the comparator circuit, the power supply circuit and the isolation circuit are combined, compared with the traditional comparison circuit, the number of elements used is less, the cost is low, the circuit is simple, and it is easier to integrate; in addition, the detection precision of the two-way voltage comparison circuit is determined by the turn-on voltage of the optocoupler and the second resistor, so as to facilitate the designer to control the detection precision of the two-way voltage comparison circuit, while ensuring the high detection precision of the two-way voltage comparison circuit, the circuit structure is simplified. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 It is a circuit diagram of the traditional two-way voltage comparison circuit; Figure 2 It is a circuit diagram of the two-way voltage comparison circuit provided by an embodiment of the present application.
[0018] Reference signs: 11, first diode; 12, second diode; 13, voltage stabilizing diode; 21, light-emitting diode; 22, isolation triode; 3, first resistor; 4, second resistor; 5, first capacitor.
[0019] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION
[0020] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only, and are used only for explanation of the present application, and cannot be understood as a limitation of the present application.
[0021] In the description of the present application, it is understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.
[0022] In the description of the present application, unless otherwise specified and limited, it is necessary to explain that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection or electrical connection, it can be the communication between the two elements, it can be direct connection, or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by the person skilled in the art according to the specific circumstances.
[0023] Referring to Figure 2 The circuit diagram of the two-way voltage comparison circuit provided by an embodiment of the present application is shown. In the present embodiment, the two-way voltage comparison circuit comprises a voltage acquisition module and a photoelectric coupler 2, wherein: The voltage acquisition module comprises a first diode 11 (D1 in reference Figure 2 ) and a second diode 12 (D2 in reference Figure 2 The photoelectric coupler 2 is internally provided with a light-emitting diode 21 and an isolation triode 22, in the present embodiment, the photoelectric coupler 2 is packaged together by the light-emitting diode 21 and the isolation triode 22, to realize electric-optical-electric conversion and electrical isolation; the first input end (i.e. A pin in reference Figure 2 ) of the photoelectric coupler 2 is connected with the anode of the light-emitting diode 21, the second input end (i.e. K pin in reference Figure 2 ) of the photoelectric coupler 2 is connected with the cathode of the light-emitting diode 21; the first output end (i.e. C pin in reference Figure 2 ) of the photoelectric coupler 2 is connected with the single-chip microcomputer port, and the second output end (i.e. B pin in reference Figure 2The ground is connected to the E pin of the optocoupler 2; when the isolation triode 22 is turned on, the first output end and the second output end of the optocoupler 2 are in a short-circuit state; when the optocoupler is turned off, the first output end and the second output end of the optocoupler 2 are in an open-circuit state; whether the optocoupler 2 is in a conduction state or an off state is determined by the single-chip microcomputer connected to the C pin of the optocoupler.
[0024] The anode of the first diode 11 is connected to the output end of the first power supply (the power supply 1 in Figure 2 the drawing), and the cathode of the first diode 11 is connected to the second input end (i.e., the cathode of the light-emitting diode 21) of the optocoupler 2; the cathode of the first diode 11 is grounded through the first resistor 3. The anode of the second diode 12 is connected to the output end of the second power supply (the power supply 2 in Figure 2 the drawing), and the cathode of the second diode 12 is connected to the first input end (i.e., the anode of the light-emitting diode 21) of the optocoupler 2; the cathode of the second diode 12 is connected to the first input end (i.e., the anode of the light-emitting diode 21) of the optocoupler 2 through the second resistor 4. The isolation triode 22 is used to receive the light signal emitted by the light-emitting diode 21 after being powered on; when the light signal is received, the isolation triode 22 is turned on, and the optocoupler 2 becomes a conduction state.
[0025] The comparator circuit, the power supply circuit and the isolation circuit are combined in the present application, the circuit is simple and easy to integrate. When the voltage output by the second power supply is greater than the voltage output by the first power supply, the working path of the circuit is: the output end of the second power supply, the second diode 12, the second resistor 4, the optocoupler 2, the first resistor 3 to the ground, the optocoupler 2 is turned on, the first output end (the C pin of the optocoupler 2) and the second output end (the E pin of the optocoupler 2) of the optocoupler 2 are short-circuited, and there is an output signal, so the voltage of the single-chip microcomputer port is 0V; When the voltage output by the second power supply is less than or equal to the voltage output by the first power supply, the working path of the circuit is: the output end of the first power supply, the first diode 11, the first resistor 3 to the ground, the optocoupler 2 is turned off, the first output end (the C pin of the optocoupler 2) and the second output end (the E pin of the optocoupler 2) of the optocoupler 2 are open-circuited, and there is no output signal, so the voltage of the single-chip microcomputer port is 5V, thereby it can be clearly determined that the output voltages of the first power supply and the second power supply are high or low.
[0026] The precision of the voltage detection of the two-way voltage comparison circuit is determined by the optoelectronic coupler 2 and the second resistor 4. For example, if the voltage to be detected is 300V, the maximum conduction voltage of the optoelectronic coupler 2 is 1.2V, and the detection precision of the two-way voltage comparison circuit is 1.2V / 300V=0.4%. The precision of 0.4% is better than the precision of 2% of the traditional comparator. In addition, due to the fixed deviation of the optoelectronic coupler and the adjustable resistance value of the second resistor 4, the interference caused by the power supply ripple voltage can be effectively reduced.
[0027] In the preferred embodiment of the present application, the voltage acquisition module further comprises a stabilizing diode 13, the anode of the stabilizing diode 13 is connected with the cathode of the first diode 11, and the cathode of the stabilizing diode 13 is connected with the cathode of the second diode 12.
[0028] The first diode 11, the second diode 12 and the stabilizing diode 13 can constitute a protection circuit. For example, when the voltage output by the first power supply is much larger than the voltage output by the second power supply, if there is no stabilizing diode 13, the optoelectronic coupler 2 will be reversely broken down by the high voltage, causing damage to the optoelectronic coupler 2. After the stabilizing diode 13 is added, even in the extreme case that only one of the first power supply and the second power supply is powered and the other power supply is 0, the current backflow can be prevented to prevent damage to the circuit.
[0029] The first capacitor 5 is connected in parallel between the anode and the cathode of the light-emitting diode 21. The connection of the first capacitor 5 and the light-emitting diode 21 can realize an anti-interference function. When the ripple voltage of the first power supply and the second power supply is large, the interference signal generated is filtered through the first capacitor 5, and under the fixed deviation of the light-emitting diode 21, the malfunction can be effectively prevented.
[0030] In the preferred embodiment of the present application, the resistance value of the first resistor 3 is adjustable, and the resistance value of the second resistor 4 is adjustable. For different voltage output power supplies, the resistance value of the first resistor 3 and / or the second resistor 4 can be adjusted to limit the current passing through the optoelectronic coupler 2, so as to ensure the reliable operation of the two-way voltage comparison circuit.
[0031] It should be noted that the number of the first resistor 3 can be one or multiple. When the voltage output by the first power supply and the voltage output by the second power supply are large, the number of the first resistor 3 can be increased. When the number of the first resistor 3 is set to multiple, the multiple first resistors 3 can be connected in series or connected in parallel.
[0032] In a high-voltage circuit, a single resistor needs to withstand a high voltage. According to the formula for calculating electric power When the voltage U is very high, even if the resistance R has a very large resistance value, its power consumption P can be very large, which can cause the resistor to overheat or even burn out; by replacing the single first resistor 3 with an equivalent resistor composed of a plurality of first resistors 3 connected in series (or a plurality of first resistors connected in parallel), the total power consumption can be shared.
[0033] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", "one implementation", "a preferred implementation" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0034] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.
Claims
1. A two-path voltage comparison circuit, characterized by, The voltage acquisition module comprises a first diode (11) and a second diode (12), the anode of the first diode (11) is connected with the output end of the first power supply; The anode of the second diode (12) is connected with the output end of the second power supply, and the cathode of the second diode (12) is connected with the first input end of the optoelectronic coupler (2); The cathode of the first diode (11) is connected with the second input end of the optoelectronic coupler (2); When the voltage inputted by the first input end of the optoelectronic coupler (2) is greater than the voltage inputted by the second input end of the optoelectronic coupler (2), the isolation triode (22) is turned on. The voltage acquisition module further comprises a voltage stabilizing diode (13), the anode of the voltage stabilizing diode (13) is connected with the cathode of the first diode (11), and the cathode of the voltage stabilizing diode (13) is connected with the cathode of the second diode (12).
2. The two-path voltage comparison circuit of claim 1, wherein, The cathode of the first diode (11) is connected with the ground through a first resistor (3), and a second resistor (4) is connected between the cathode of the second diode (12) and the first input end of the optoelectronic coupler (2).
3. The two-path voltage comparison circuit of claim 1, wherein, The resistance value of the first resistor (3) is adjustable, and the resistance value of the second resistor (4) is adjustable.
4. The two-path voltage comparison circuit of claim 3, wherein, A plurality of first resistors (3) are provided, and the plurality of first resistors (3) are connected in series or in parallel.
5. The two-path voltage comparison circuit of claim 3, wherein, A first capacitor (5) is connected in parallel between the first input end of the optoelectronic coupler (2) and the second input end of the optoelectronic coupler (2).
6. The two-path voltage comparison circuit of any one of claims 1 to 5, wherein,