Passive and active compatible signal control circuit

Abstract

The utility model relates to a passive and active compatible signal control circuit, which comprises an external input protection module, a current limiting driving module, an optocoupler isolation signal module, a filter level output module and a single chip microcomputer. Passive signals and active signals can be processed at the same time through the circuit, independent input ports do not need to be distributed for different types of signals, product port resources are greatly saved, and the compatibility processing of the passive signals and the active signals is achieved, so that the compatibility processing efficiency is improved. A user does not need to prepare different wiring modes for different types of signal sources during use, so that the wiring process is simplified, the use difficulty is reduced, meanwhile, the failure rate caused by wiring errors is reduced, in addition, ports are saved, wiring is simplified, the overall size and weight of the product are reduced, and the portability is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a passive and active compatible signal control circuit. Background Art

[0002] In the design and application of electronic products, the limited nature of port resources is an issue that cannot be ignored. Especially in portable devices, compact control systems, or electronic products with limited space, every port and interface is particularly precious. Traditionally, when a product needs to receive external control signals, it is usually necessary to design and allocate independent input ports for different types of signals. However, this approach not only increases the complexity and cost of the product but also limits the flexibility and portability of the product. Summary of the Invention

[0003] In view of this, the purpose of the utility model is to provide a passive and active compatible signal control circuit that saves ports, simplifies wiring, and is convenient to use.

[0004] To achieve the above purpose, the utility model adopts such a passive and active compatible signal control circuit, which includes an external input protection module, a current limiting drive module, an optocoupler isolation signal module, a filtering level output module, and a single-chip microcomputer. The output end of the external input protection module is connected to the input end of the current limiting drive module, the output end of the current limiting drive module is connected to the input end of the optocoupler isolation signal module, the output end of the optocoupler isolation signal module is connected to the input end of the filtering level output module, and the output end of the filtering level output module is connected to the input end of the single-chip microcomputer.

[0005] The utility model is further configured such that the external input protection module includes a zener diode, a diode, an external signal input terminal IN, and a common ground interface COM. The zener diode is used to limit the input voltage not to exceed a preset value, the diode is used to prevent the reverse voltage from damaging the circuit, and the external signal input terminal IN is used to receive external passive signals or active signals.

[0006] The utility model is further configured such that the current limiting drive module is composed of two triodes and three resistors. The current limiting drive module limits and controls the current flowing to the optocoupler isolation signal module by adjusting the conduction state of the triodes to protect the circuit from damage caused by excessive current.

[0007] The utility model is further configured such that the optocoupler isolation signal module includes an optocoupler isolation signal circuit and a current limiting circuit. The optocoupler isolation signal circuit includes optocouplers U1 and U2, which are used to achieve electrical isolation of signals.

[0008] This utility model is further configured such that the current limiting circuit includes at least one resistor, and the resistor is connected between the light emitting end of optocoupler U2 and the output end of the current limiting driving module, and the resistor is used to limit the current flowing to the light emitting end of optocoupler U2.

[0009] This utility model is further configured such that the filtering level output module consists of a filtering capacitor, a resistor, and a digital output port OUTPUT. The filtering capacitor is used to filter out high-frequency noise in the signal, the resistor is used to adjust the level of the output signal or match the impedance, and the digital output port OUTPUT is used to output the processed signal to the single-chip microcomputer in a level form suitable for the single-chip microcomputer to process.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows: Through this circuit, passive signals and active signals can be processed simultaneously without allocating independent input ports for different types of signals, greatly saving the product port resources. And because the compatible processing of passive and active signals is realized, users do not need to prepare different wiring methods for different types of signal sources when using, thus simplifying the wiring process, reducing the usage difficulty. At the same time, it also reduces the failure rate caused by wiring errors. In addition, due to saving ports and simplifying wiring, the overall volume and weight of the product are also reduced, thereby improving portability. Description of the Drawings

[0011] Figure 1 is the circuit schematic diagram of the embodiment of this utility model. Detailed Embodiment

[0012] As Figure 1 shown, the embodiment of this utility model provides a passive and active compatible signal control circuit, including an external input protection module, a current limiting driving module, an optocoupler isolation signal module, a filtering level output module, and a single-chip microcomputer. The output end of the external input protection module is connected to the input end of the current limiting driving module, the output end of the current limiting driving module is connected to the input end of the optocoupler isolation signal module, the output end of the optocoupler isolation signal module is connected to the input end of the filtering level output module, and the output end of the filtering level output module is connected to the input end of the single-chip microcomputer (not all details are drawn in the figure, but the connection points with the filtering level output module are shown).

[0013] The external input protection module consists of a voltage stabilizing diode D2, a diode D3, an external signal input terminal IN, and a common ground interface COM. The voltage stabilizing diode D2 is used to limit the input voltage not exceeding a preset value, the diode D3 is used to prevent reverse voltage from damaging the circuit, and the external signal input terminal IN receives external passive signals (0 - 5V) or active signals (5 - 24V).

[0014] The current limiting drive module consists of transistor Q1, transistor Q2, and resistors R3 to R5. This module limits and controls the current flowing to the optocoupler isolation signal module by adjusting the conduction state of the transistors, protecting the circuit from damage caused by excessive current.

[0015] The optocoupler isolation signal module includes an optocoupler isolation signal circuit and a current limiting circuit. The optocoupler isolation signal circuit consists of optocouplers U1 and U2 and is used to achieve electrical isolation of signals. The current limiting circuit consists of a resistor R1, which is connected between the light emitting end of optocoupler U2 and the output end of the current limiting drive module. Resistor R1 is used to limit the current flowing to the light emitting end of optocoupler U2.

[0016] The filtering level output module consists of filtering capacitor C1, resistor R2, and digital output port OUTPUT. Filtering capacitor C1 is used to filter out high-frequency noise in the signal, while resistor R2 is used to adjust the level of the output signal or match the impedance. Digital output port OUTPUT is used to output the processed signal to the microcontroller in a level form suitable for microcontroller processing.

[0017] Specifically, the external signal input terminal IN is respectively connected to the negative electrode of voltage stabilizing diode D2 and the negative electrode of diode D3. The positive electrode of diode D3 is connected to the +3.3V power supply. The positive electrode of voltage stabilizing diode D2 is respectively connected to one end of resistor R3 and the positive electrode of the light emitting end of optocoupler U1. The negative electrode of the light emitting end of optocoupler U1 is connected to the collector of transistor Q1. The base of transistor Q1 is respectively connected to the other end of resistor R3 and the collector of transistor Q2. The emitter of transistor Q1 is respectively connected to the base of transistor Q2 and one end of resistor R4. The other end of resistor R4, the emitter of transistor Q2, and one end of resistor R5 are all connected to the common ground interface COM. The other end of resistor R5 is respectively connected to one end of resistor R1 and the positive electrode of the light emitting end of optocoupler U2. The negative electrode of the light emitting end of optocoupler U2 and the other end of resistor R1 are both grounded. The collector of the light receiving end of optocoupler U1 is respectively connected to the collector of the light receiving end of optocoupler U2, one end of filtering capacitor C1, one end of resistor R2, and digital output port OUTPUT. Digital output port OUTPUT is connected to the microcontroller. The other end of resistor R2 is connected to the +3.3V power supply. The emitter of the light receiving end of optocoupler U1, the emitter of the light receiving end of optocoupler U2, and the other end of filtering capacitor C1 are all grounded.

[0018] Working principle of the utility model: When a passive signal (0 - 5V) is input, when the external signal input terminal IN receives a passive signal of 0 - 5V and the common ground interface COM is correctly grounded, the circuit starts to work. Due to the forward conduction characteristic of diode D3 and the clamping effect of zener diode D2, the potential at point A is limited to below about 1.1V (considering the zener voltage of zener diode D2 and the forward conduction voltage drop of diode D3). At this time, triode Q1 is in a cut-off or weakly conducting state due to insufficient base voltage and cannot provide enough drive current for optocoupler U1. Therefore, the light-receiving end of optocoupler U1 remains in a high-impedance state and does not conduct, resulting in the OUTPUT terminal of the filter level output module maintaining a high level state, and the single-chip microcomputer does not perform any action.

[0019] When an active signal (5 - 24V) is input, when the external signal input terminal IN receives an active signal of 5 - 24V, the potential at point A increases with the increase of the input voltage. Once the potential at point A is higher than the conduction threshold of optocoupler U1, optocoupler U1 starts to conduct, and its light-receiving end outputs a low-level signal. This low-level signal is filtered by filter capacitor C1 and the level is adjusted by resistor R2, and then is stably sent to the OUTPUT terminal, thereby triggering the single-chip microcomputer to perform corresponding actions. At the same time, the current limiting drive module stabilizes the current flowing through optocoupler U1 within a safe range through the constant current characteristics of triode Q1 and triode Q2 to prevent the circuit from being damaged due to overcurrent.

[0020] In some special cases, when the COM terminal is accidentally short-circuited to the external ground, the potential at the COM point may no longer be 0V, but is maintained at about 2.7V under the action of the internal power supply of the product. At this time, if the input signal is still 5 - 24V and meets the conduction condition of optocoupler U2, optocoupler U2 will conduct and pull down the potential of the OUTPUT terminal through its light-receiving end, thereby triggering the single-chip microcomputer to perform actions. This design increases the flexibility and fault tolerance of the circuit, enabling the circuit to still maintain a certain functionality and stability under abnormal conditions.

[0021] Of course, in addition to the above embodiments, the utility model can also have many other embodiments. Without departing from the essence of the technical solution of the utility model, those skilled in the art can make various corresponding changes and deformations according to the utility model. And if these changes or deformations are equivalent to the technical solutions in this patent, then these corresponding changes and deformations should all fall within the protection scope of the appended claims of the utility model, and this utility model creation meets the actual R & D capabilities and resource conditions of the applicant.

Claims

1. A passive and active compatible signal control circuit, characterized in that: It includes an external input protection module, a current limit drive module, an optocoupler isolation signal module, a filter level output module, and a single-chip microcomputer. The output end of the external input protection module is connected to the input end of the current limit drive module. The output end of the current limit drive module is connected to the input end of the optocoupler isolation signal module. The output end of the optocoupler isolation signal module is connected to the input end of the filter level output module. The output end of the filter level output module is connected to the input end of the single-chip microcomputer.

2. The passive-active compatible signal control circuit according to claim 1, wherein: The external input protection module includes a voltage stabilizing diode, a diode, an external signal input terminal IN, and a common ground interface COM. The voltage stabilizing diode is used to limit the input voltage not to exceed a preset value. The diode is used to prevent the reverse voltage from damaging the circuit. The external signal input terminal IN is used to receive external passive signals or active signals.

3. The passive and active compatible signal control circuit according to claim 1, wherein: The current limit drive module is composed of two triodes and three resistors. The current limit drive module limits and controls the current flowing to the optocoupler isolation signal module by adjusting the conduction state of the triodes to protect the circuit from excessive current damage.

4. The passive-active compatible signal control circuit according to claim 1, characterized in that: The optocoupler isolation signal module includes an optocoupler isolation signal circuit and a current limiting circuit. The optocoupler isolation signal circuit includes optocouplers U1 and U2, which are used to achieve electrical isolation of signals.

5. The passive-active compatible signal control circuit according to claim 4, wherein: The current limiting circuit includes at least one resistor. The resistor is connected between the light emitting end of optocoupler U2 and the output end of the current limit drive module. The resistor is used to limit the current flowing to the light emitting end of optocoupler U2.

6. The passive-active compatible signal control circuit according to claim 1, wherein: The filter level output module is composed of a filter capacitor, a resistor, and a digital output port OUTPUT. The filter capacitor is used to filter out high-frequency noise in the signal. The resistor is used to adjust the level of the output signal or match the impedance. The digital output port OUTPUT is used to output the processed signal to the single-chip microcomputer in a level form suitable for the single-chip microcomputer to process.

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