A fault indication device based on a single-chip microcomputer
By processing the fault code signal through the signal conditioning unit and the optocoupler isolation unit, the problem of common-mode interference in complex electromagnetic environments of the single-chip microcomputer fault indication device is solved, and the reliability and accuracy of fault diagnosis are realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHENGDU HONGYI TECH LTD CORP
- Filing Date
- 2025-07-14
- Publication Date
- 2026-06-19
AI Technical Summary
Existing fault coding indication devices based on single-chip microcomputers are susceptible to common-mode interference in complex electromagnetic environments, leading to false alarms, decreased diagnostic reliability, and a high rate of incorrect repairs.
The fault code signal is processed by a signal conditioning unit and an optocoupler isolation unit. Common-mode interference is eliminated by signal conditioning filtering and optocoupler isolation to ensure that the signal remains effective before being transmitted to the main processor.
It improves the reliability and quality of fault code signal acquisition, reduces the probability of incorrect maintenance due to misjudgment, and enhances the accuracy of fault diagnosis.
Smart Images
Figure CN224383393U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit technology, specifically to a fault indication device based on a microcontroller. Background Technology
[0002] In the design of conventional audio power amplifiers without displays, microcontroller-based fault code indicator lights have become the mainstream fault indication solution due to their low cost and ease of implementation. This solution conveys fault information through preset light codes, such as flashing frequency and color combinations, helping maintenance personnel quickly locate faulty modules, such as the power supply unit or the left and right channel units of the power amplifier.
[0003] However, within complex high-power audio equipment, there exists a long-overlooked but seriously problematic technical flaw that significantly impacts diagnostic reliability: fault code indicator lights are susceptible to common-mode interference, leading to false alarms. These indicator lights require highly reliable drivers to achieve complex flashing codes, while the strong electromagnetic environment inside the power amplifier demands extreme interference immunity from the circuitry. Existing solutions cannot satisfy both requirements, resulting in a significant decrease in diagnostic reliability when the fault code signal is input to the microcontroller for fault display. Industry reports indicate that in switching power supply faults, the erroneous repair rate due to indicator light false alarms is as high as 15%-22%, substantially increasing after-sales costs. Utility Model Content
[0004] This invention provides a fault indication device based on a microcontroller, which solves the problem that existing fault coding indication devices are susceptible to common-mode interference when detecting audio power amplifiers, leading to abnormal signals in the detection equipment.
[0005] This utility model is achieved through the following technical solution:
[0006] A fault indication device based on a microcontroller includes a microcontroller-based main processor, the main processor including a first input terminal, a second input terminal, a first output terminal and a display output terminal; it also includes a signal conditioning unit, an optocoupler isolation unit and a display unit;
[0007] The input terminal of the signal conditioning unit is connected to an external fault code signal, and the output terminal of the signal conditioning unit is connected to the first input terminal of the main processor; the input terminal of the optocoupler isolation unit is connected to the first output terminal of the main processor, and the output terminal of the optocoupler isolation unit is connected to the second input terminal of the main processor; the display output terminal is connected to the input terminal of the display unit.
[0008] Fault code indicator lights require high-sensitivity drives to achieve complex flashing codes, while the strong electromagnetic environment inside the power amplifier demands extreme anti-interference capabilities from the circuitry. Existing solutions cannot satisfy both requirements, resulting in a significant decrease in diagnostic reliability when the fault code signal is input to the microcontroller for fault display. Industry reports show that in switching power supply faults, the error repair rate due to false alarms from indicator lights is as high as 15%-22%, significantly increasing after-sales costs. Therefore, this invention provides a microcontroller-based fault indication device that solves the problem of existing fault code indicator devices being susceptible to common-mode interference, leading to abnormal equipment signals.
[0009] Further, let the first input terminal be denoted as A1; the signal conditioning unit includes a first resistor R1, a first diode VD1, a first capacitor C1, a second resistor R2, and a first amplifier U1. One end of the first resistor R1 is set as the output terminal of the signal conditioning unit and is denoted as the total input terminal Q. The other end of the first resistor R1 is connected to the anode of the first diode VD1, one end of the first capacitor C1, and the non-inverting input terminal of the first amplifier U1 at the same point and is denoted as E1. The cathode of the first diode VD1 is connected to the other end of the first capacitor C1, one end of the second resistor R2, and the inverting input terminal of the first amplifier U1 at the same point, and the other end of the second resistor R2 is grounded. The output terminal of the first amplifier U1 is connected to the first input terminal A1.
[0010] Furthermore, the signal conditioning unit also includes an eighth resistor R8 and a third capacitor C3; one end of the eighth resistor R8 is connected to terminal E1, the other end of the eighth resistor is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is connected to the output terminal of the first amplifier U1.
[0011] Furthermore, the signal conditioning unit also includes a fourth capacitor C4, one end of which is connected to terminal E1, and the other end is connected to the same point as the other end of the eighth resistor and one end of the third capacitor C3.
[0012] Further, let the second input terminal be denoted as A2 and the first output terminal as Z1; the optocoupler isolation unit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second diode VD2 and a first inductor L1. One end of the third resistor R3 is connected to one end of the fifth resistor R5, the anode of the second diode VD2 and the first output terminal Z1 at the same point, and the other end of the third resistor R3 is provided with a first voltage source VCC1; the other end of the fifth resistor R5 is connected to one end of the third capacitor C3, and the cathode of the second diode VD2 is connected to one end of the first inductor L1; one end of the fourth resistor R4 is connected to the other end of the third capacitor C3, the other end of the first inductor L1 and the second input terminal A2 at the same point and the endpoint is set as E2.
[0013] Furthermore, the optocoupler isolation unit also includes a sixth resistor R6 and a third diode ZD. One end of the sixth resistor R6 and the cathode of the third diode ZD are both connected to the terminal E2; the other end of the sixth resistor R6 and the anode of the third diode ZD are connected to the same terminal and grounded.
[0014] Furthermore, the optocoupler isolation unit also includes a seventh resistor R7 and a second capacitor C2; one end of the seventh resistor R7 is connected to the endpoint E2, the other end of the seventh resistor R7 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is connected to the same point as the other end of the fifth resistor R5 and one end of the third capacitor C3.
[0015] Furthermore, the third diode ZD is configured as a Zener diode.
[0016] Furthermore, the display unit includes an LED module, the display output terminal includes a P0 terminal, a P1 terminal, a P2 terminal and a P3 terminal, and the input terminal of the display unit includes a D0 terminal, a D1 terminal, a D2 terminal and a D3 terminal disposed on the LED module; the P0 terminal is connected to the D0 terminal, the P1 terminal is connected to the D1 terminal, the P2 terminal is connected to the D2 terminal, and the P3 terminal is connected to the D3 terminal.
[0017] Furthermore, the LED module is provided with a negative power supply terminal VSS, which is connected to a third power supply terminal VCC3.
[0018] Compared with the prior art, this invention, after two-stage processing of signal conditioning and optocoupler isolation, only enters the main processor control logic if the fault signal is still valid after interference isolation. This enables the system to accurately distinguish between real faults and interference signals in complex electromagnetic environments, reducing the probability of erroneous maintenance due to misjudgment and significantly improving the reliability and signal quality of fault code signal acquisition. Attached Figure Description
[0019] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings:
[0020] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model. Example
[0022] like Figure 1 As shown, this embodiment is a fault indication device based on a microcontroller, including a microcontroller-based main processor. The main processor includes a first input terminal, a second input terminal, a first output terminal, and a display output terminal; it also includes a signal conditioning unit, an optocoupler isolation unit, and a display unit.
[0023] The input terminal of the signal conditioning unit is connected to an external fault code signal, and the output terminal of the signal conditioning unit is connected to the first input terminal A1 of the main processor; the input terminal of the optocoupler isolation unit is connected to the first output terminal Z1 of the main processor, and the output terminal of the optocoupler isolation unit is connected to the second input terminal A2 of the main processor; the display output terminal is connected to the input terminal of the display unit.
[0024] Further, let the first input terminal be denoted as A1; the signal conditioning unit includes a first resistor R1, a first diode VD1, a first capacitor C1, a second resistor R2, and a first amplifier U1. One end of the first resistor R1 is set as the output terminal of the signal conditioning unit and denoted as the total input terminal Q. The other end of the first resistor R1 is connected to the anode of the first diode VD1, one end of the first capacitor C1, and the non-inverting input terminal of the first amplifier U1 at the same point and denoted as E1. The cathode of the first diode VD1 is connected to the other end of the first capacitor C1, one end of the second resistor R2, and the inverting input terminal of the first amplifier U1. The input terminals are connected to the same point, and the other end of the second resistor R2 is grounded; the output terminal of the first amplifier U1 is connected to the first input terminal A1; the signal conditioning unit also includes an eighth resistor R8 and a third capacitor C3; one end of the eighth resistor R8 is connected to terminal E1, and the other end of the eighth resistor is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is connected to the output terminal of the first amplifier U1; the signal conditioning unit also includes a fourth capacitor C4, one end of the fourth capacitor C4 is connected to terminal E1, and the other end is connected to the same point as the other end of the eighth resistor and one end of the third capacitor C3.
[0025] Further, let the second input terminal be denoted as A2 and the first output terminal as Z1; the optocoupler isolation unit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second diode VD2, and a first inductor L1. One end of the third resistor R3 is connected to one end of the fifth resistor R5, the anode of the second diode VD2, and the first output terminal Z1 at the same point, and the other end of the third resistor R3 is provided with a first voltage source VCC1; the other end of the fifth resistor R5 is connected to one end of the third capacitor C3, and the cathode of the second diode VD2 is connected to one end of the first inductor L1; one end of the fourth resistor R4 is connected to the other end of the third capacitor C3, the other end of the first inductor L1, and the second input terminal Z1 at the same point. Terminal A2 is connected to the same point and designated as endpoint E2; the optocoupler isolation unit also includes a sixth resistor R6 and a third diode ZD, one end of the sixth resistor R6 and the cathode of the third diode ZD are both connected to endpoint E2; the other end of the sixth resistor R6 and the anode of the third diode ZD are connected to the same endpoint and grounded; the optocoupler isolation unit also includes a seventh resistor R7 and a second capacitor C2; one end of the seventh resistor R7 is connected to endpoint E2, and the other end of the seventh resistor R7 is connected to one end of the second capacitor C2, the other end of the second capacitor C2 is connected to the same point as the other end of the fifth resistor R5 and one end of the third capacitor C3; the third diode ZD is configured as a Zener diode.
[0026] Furthermore, the display unit includes an LED module, the display output terminal includes a P0 terminal, a P1 terminal, a P2 terminal, and a P3 terminal, and the input terminal of the display unit includes a D0 terminal, a D1 terminal, a D2 terminal, and a D3 terminal disposed on the LED module; the P0 terminal is connected to the D0 terminal, the P1 terminal is connected to the D1 terminal, the P2 terminal is connected to the D2 terminal, and the P3 terminal is connected to the D3 terminal; the LED module is provided with a negative power supply terminal VSS, and the negative power supply terminal VSS is connected to a third power supply terminal VCC3.
[0027] In this implementation, the main processor is a microcontroller, which serves to connect and process data between various modules. The signal conditioning unit amplifies and filters the fault code signal before inputting it to the main processor. After receiving the fault code signal from the signal conditioning unit, the main processor forwards the signal to the first output terminal and outputs it to the optocoupler isolation unit. The optocoupler isolation unit eliminates common-mode interference in the fault code signal. After the common-mode interference-eliminated fault code signal is transmitted back to the main processor, the main processor transmits instructions to the display unit to display the fault code according to binary ordinal numbers to indicate the fault type.
[0028] During operation, the signal conditioning unit forms a feedback closed-loop structure from input to output. When external environmental disturbances occur, such as power surges or power amplifier switching, this circuit can quickly filter out fluctuations and maintain stable output. The fault code signal enters from the total input terminal Q of the signal conditioning unit. The signal first passes through the first resistor R1 for current limiting to prevent strong sudden signal changes from impacting subsequent circuits. It then enters terminal E1, where it is fed to the anode of VD1 for amplitude limiting protection, to the first capacitor C1 for bypass filtering of high-frequency spikes, and to the non-inverting input terminal of the first amplifier U1. The first diode VD1 acts as a clamping protection; when the input voltage exceeds the diode's conduction threshold, VD1 conducts, limiting the input signal overvoltage and protecting the first amplifier U1. The first capacitor C1 bypasses high-frequency spikes to ground, suppressing glitches; at this time, terminal E1 becomes a protected and filtered signal node. The second resistor R2 forms a bias channel between the cathode of the first diode VD1 and ground, providing a necessary negative feedback closed-loop path for the first operational amplifier U1; it also forms a voltage divider and suppresses negative input terminal floating, stabilizing the differential input. The first amplifier U1, the first diode VD1, and the first capacitor C1 form a negative path, creating a symmetrical signal filtering structure. The first amplifier U1 operates in non-inverting mode, amplifying the input signal from terminal E1 before outputting it; the eighth resistor R8 and the third capacitor C3 form a negative feedback path, controlling the gain and bandwidth of the first amplifier U1; the fourth capacitor C4 is connected in parallel in the feedback path, enhancing high-frequency suppression capability; finally, the output signal is sent from the output terminal of the first amplifier U1 to the first input terminal A1 of the main processor. At this point, the fault code signal has completed limiting, filtering, and amplification processing, possessing clear level transitions and stable timing information.
[0029] The optocoupler isolation unit employs an equivalent isolation mechanism without an optocoupler structure, using a combination of specific components to simulate an anti-interference signal isolation channel. Its operation can be divided into signal emission, isolation processing, and final feedback to the main processor. The third resistor R3 and the second diode VD2 are used for optocoupler drive input; the first inductor L1 and the fifth resistor R5 form an optocoupler channel to filter common-mode interference; the fourth resistor R4, the sixth resistor R6, and the third diode ZD are used to suppress signal voltage overshoot, protect the MCU input, provide level stability, and adjust the optocoupler output level; the seventh resistor R7, the second capacitor C2, and the third capacitor C3 are used for path filtering, with the third capacitor C3 acting as a coupling buffer to provide a smooth transition at the isolation boundary. The main processor outputs the amplified and filtered fault code signal through the first output terminal Z1. The signal is current-limited by the third resistor R3 to prevent excessive current from entering the subsequent stage and damaging the optocoupler input section. Simultaneously, it is voltage-divided by the fifth resistor R5 and enters the next stage filter. The second diode VD2 receives the signal at its anode and outputs it from its cathode. This prevents reverse voltage from damaging the isolation structure, allowing only forward drive to propel the signal into the inductor and optocoupler channels of the next stage. After flowing out from the cathode of the second diode VD2, the current passes through the first inductor L1 to terminal E2. The first inductor L1 acts as an impedance barrier against common-mode interference, suppressing high-frequency interference components. The signal enters the second input terminal A2 of the main controller from terminal E2 to confirm whether the encoded signal has been corrupted during transmission. If the voltage at terminal E2 is too high, exceeding the voltage regulation threshold of the third diode ZD, the Zener diode conducts, directing the excess current to ground through the sixth resistor R6. The fourth resistor R4 acts as a current-limiting resistor for the optocoupler, protecting the second input terminal A2 of the main processor from burnout due to surge voltage. The seventh resistor R7 and the second capacitor C2 form an RC buffer filter, creating a "gradual rise and fall" mechanism for the feedback channel to resist sharp voltage jumps. The third capacitor C3, together with the fifth resistor R5, filters out tail spikes. Even if a signal change occurs at the first output terminal Z1 of the main control, it will not be immediately conducted in the feedback loop, effectively filtering false jumps. In this embodiment, as a feasible implementation, the negative terminal VSS of the LED module is connected to the positive terminal of the VCC3 power supply. This module adopts a common anode LED structure, that is, multiple LEDs share a common anode connected to a high level, and each cathode is connected to the MCU output port. Display control logic: when the MCU outputs a low level, the LED is turned on, making the light on; when the output is high, the LED is turned off, making the light off.
[0030] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A fault indication device based on a microcontroller, comprising a microcontroller-based main processor, characterized in that, The main processor includes a first input terminal, a second input terminal, a first output terminal, and a display output terminal; it also includes a signal conditioning unit, an optocoupler isolation unit, and a display unit. The input terminal of the signal conditioning unit is connected to an external fault code signal, and the output terminal of the signal conditioning unit is connected to the first input terminal of the main processor; the input terminal of the optocoupler isolation unit is connected to the first output terminal of the main processor, and the output terminal of the optocoupler isolation unit is connected to the second input terminal of the main processor; the display output terminal is connected to the input terminal of the display unit.
2. The fault indication device based on a microcontroller according to claim 1, characterized in that, Let the first input terminal be denoted as A1; the signal conditioning unit includes a first resistor R1, a first diode VD1, a first capacitor C1, a second resistor R2, and a first amplifier U1. One end of the first resistor R1 is set as the output terminal of the signal conditioning unit and is denoted as the total input terminal Q. The other end of the first resistor R1 is connected to the anode of the first diode VD1, one end of the first capacitor C1, and the non-inverting input terminal of the first amplifier U1 at the same point and is denoted as E1. The cathode of the first diode VD1 is connected to the other end of the first capacitor C1, one end of the second resistor R2, and the inverting input terminal of the first amplifier U1 at the same point, and the other end of the second resistor R2 is grounded. The output terminal of the first amplifier U1 is connected to the first input terminal A1.
3. The fault indication device based on a microcontroller according to claim 2, characterized in that, The signal conditioning unit also includes an eighth resistor R8 and a third capacitor C3; one end of the eighth resistor R8 is connected to terminal E1, the other end of the eighth resistor is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is connected to the output terminal of the first amplifier U1.
4. The fault indication device based on a microcontroller according to claim 3, characterized in that, The signal conditioning unit also includes a fourth capacitor C4, one end of which is connected to terminal E1, and the other end is connected to the same point as the other end of the eighth resistor and one end of the third capacitor C3.
5. A fault indication device based on a microcontroller according to claim 1, characterized in that, set up The second input terminal is designated A2, and the first output terminal is designated Z1. The optocoupler isolation unit includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second diode VD2, and a first inductor L1. One end of the third resistor R3 is connected to one end of the fifth resistor R5, the anode of the second diode VD2, and the first output terminal Z1 at the same point, and the other end of the third resistor R3 is provided with a first voltage source VCC1. The other end of the fifth resistor R5 is connected to one end of the third capacitor C3, and the cathode of the second diode VD2 is connected to one end of the first inductor L1. One end of the fourth resistor R4 is connected to the other end of the third capacitor C3, the other end of the first inductor L1, and the second input terminal A2 at the same point, and the endpoint is designated E2.
6. A fault indication device based on a microcontroller according to claim 5, characterized in that, The optocoupler isolation unit also includes a sixth resistor R6 and a third diode ZD. One end of the sixth resistor R6 and the cathode of the third diode ZD are both connected to the terminal E2; the other end of the sixth resistor R6 and the anode of the third diode ZD are connected to the same terminal and grounded.
7. A fault indication device based on a microcontroller according to claim 5, characterized in that, The optocoupler isolation unit also includes a seventh resistor R7 and a second capacitor C2; one end of the seventh resistor R7 is connected to the endpoint E2, and the other end of the seventh resistor R7 is connected to one end of the second capacitor C2. The other end of the second capacitor C2 is connected to the same point as the other end of the fifth resistor R5 and one end of the third capacitor C3.
8. A fault indication device based on a microcontroller according to claim 6, characterized in that, The third diode ZD is configured as a Zener diode.
9. A fault indication device based on a microcontroller according to claim 1, characterized in that, The display unit includes an LED module, the display output terminal includes a P0 terminal, a P1 terminal, a P2 terminal and a P3 terminal, and the input terminal of the display unit includes a D0 terminal, a D1 terminal, a D2 terminal and a D3 terminal disposed on the LED module; the P0 terminal is connected to the D0 terminal, the P1 terminal is connected to the D1 terminal, the P2 terminal is connected to the D2 terminal, and the P3 terminal is connected to the D3 terminal.
10. A fault indication device based on a microcontroller according to claim 9, characterized in that, The LED module is provided with a negative power supply terminal VSS, which is connected to a third power supply terminal VCC3.