A circuit structure for isolating an input power supply and an input signal

Abstract

The present application relates to signal processing circuit technical field, specifically, it relates to a kind of circuit structure for isolating input power supply and input signal.The structure includes DC power input module CN0 and signal input module CN1, it is characterized in that, the positive pole of DC power input module CN0 is electrically connected with the input positive pole of DC-DC isolated power supply, the negative pole of DC power input module CN0 is electrically connected with the input negative pole of DC-DC isolated power supply.Signal input module CN1 positive pole is electrically connected with the output positive pole of DC-DC isolated power supply, signal input module CN1 negative pole is electrically connected with the input anode of photoelectric coupler U1, the input cathode of photoelectric coupler U1 is electrically connected with the output negative pole of DC-DC isolated power supply, and the collector, emitter between photoelectric coupler U1 is electrically connected with signal output module CN9.Through the above structure, the technical scheme of the application realizes that weak current system input module and front-end signal line are completely electrically isolated on power supply and signal path.

Description

Technical Field

[0001] This invention relates to the field of signal processing circuit technology, and more specifically, to a circuit structure for isolating input power supply and input signal. Background Technology

[0002] Currently, the input signals of low-voltage electrical systems in subways and large buildings are susceptible to potential risks such as signal interference and high-voltage interference due to the diverse field equipment and complex wiring. To address short-circuit faults, existing systems incorporate isolation modules in the signal loops. These modules, typically composed of electronic switches or dedicated chips, automatically disconnect the loop segment when a short circuit (i.e., a low-impedance path) is detected between two conductors, protecting other devices on the bus. Under normal electrical conditions, this structure functions effectively.

[0003] However, existing technologies suffer from the following major drawbacks: 1. Limited functionality, unable to isolate high-voltage interference: Existing isolation modules are designed to handle "short-circuit faults at the same voltage level," with their detection mechanism based on a sharp drop in loop impedance. However, field faults often manifest as high-voltage signals (e.g., DC above 28V, or even AC 220V) entering the input signal line due to factors such as humidity, insulation aging, or loose connections between signal lines and high-voltage cables. In this case, the signal line is not a low-impedance short circuit to ground, and existing isolation modules cannot identify and cut off such faults, allowing high-voltage signals to directly enter the low-voltage system through the input module. 2. Chain reaction damage with severe consequences: Once a high-voltage signal enters the detection signal line through the input module, it will sequentially damage the input module and other devices on the same circuit, ultimately leading to damage to the host system and system failure, causing significant safety hazards and economic losses. This is a serious technical challenge currently faced by various low-voltage monitoring systems. Summary of the Invention

[0004] The purpose of this invention is to provide a circuit structure for isolating input power and input signals to address the above problems. This structure completely electrically isolates the input modules of each subsystem of the low-voltage system from the front-end signal lines, ensuring the safety of the input modules and the back-end system even if high voltage is accidentally introduced into the signal lines.

[0005] To achieve the above objectives, the present invention discloses a circuit structure for isolating input power and input signals. The structure includes a DC power input module CN0 and a signal input module CN1. The positive terminal of the DC power input module CN0 is electrically connected to the positive input terminal of the DC-DC isolated power supply, and the negative terminal of the DC power input module CN0 is electrically connected to the negative input terminal of the DC-DC isolated power supply.

[0006] In use, the DC power supply is connected to a DC-DC isolated power supply for DC-DC isolation conversion, and outputs an isolated power supply that has no electrical connection with the input terminal to power the signal isolation section, achieving a power isolation voltage of 1500 volts.

[0007] The positive terminal of signal input module CN1 is electrically connected to the positive output terminal of DC-DC isolated power supply, the negative terminal of signal input module CN1 is electrically connected to the input anode of optocoupler U1, the input cathode of optocoupler U1 is electrically connected to the negative output terminal of DC-DC isolated power supply, and the collector and emitter of optocoupler U1 are electrically connected to signal output module CN9.

[0008] In use, the optocoupler U1 achieves electrical isolation of up to 5000 volts between the input and output. The input electrical signal is converted into an optical signal and then restored to an electrical signal output. There is no direct electrical connection between the two circuits.

[0009] Preferably, the input anode and input cathode of the optocoupler U1 are electrically connected in parallel with a transient voltage suppression diode (TVS1) and a signal status indicator LED1, and the signal status indicator resistor (R102) is connected in series with the signal status indicator LED1.

[0010] In use, the transient voltage suppression diode TVS1 clamps the instantaneous high voltage surge that appears at the input terminal to a safe level, realizing overvoltage and surge protection; the signal status indicator LED1 lights up and turns off synchronously with the input side of the optocoupler U1, intuitively indicating the signal status of the current channel.

[0011] Preferably, the emitter of the optocoupler U1 is electrically connected to the reverse connection protection diode D1 between the signal output module CN9 and the optocoupler U1.

[0012] When in use, the reverse polarity protection diode D1 ensures that the output signal polarity is correct, thus achieving reverse polarity protection.

[0013] Preferably, the collector and emitter of the optocoupler U1 are electrically connected to a short-circuit protection resistor R103.

[0014] When in use, the short-circuit protection resistor R103 is used to prevent short circuit between the collector and emitter of the optocoupler U1, which helps to improve safety.

[0015] Preferably, a resistor R101 is electrically connected between the input anode of the optocoupler U1 and the signal input module CN1.

[0016] In use, the electrical connection resistor R101 is used to prevent short circuit between the input anode and input cathode of the optocoupler U1, which helps to improve safety.

[0017] Preferably, the input cathode of the optocoupler U1 is electrically connected to the output negative terminal of the DC-DC isolated power supply via the input fuse F1.

[0018] When in use, fuse F1 will blow when the signal input current is abnormal, thus achieving overcurrent protection.

[0019] Preferably, a fuse F0 and a diode D0 are electrically connected between the positive terminal of the DC power input module CN0 and the positive input terminal of the DC-DC isolated power supply.

[0020] In use, the fuse F0 blows when the input current increases abnormally, achieving overcurrent protection; the diode D0 is reverse-biased when the positive and negative terminals of the input power supply are reversed, achieving reverse connection protection.

[0021] Preferably, the positive and negative output terminals of the DC-DC isolated power supply are electrically connected in series with a power indicator LED0 and a power indicator resistor R0.

[0022] When in use, the power indicator LED0 is lit, indicating that the isolated power supply is working normally, which makes it easy for maintenance personnel to quickly determine the power status of the device.

[0023] Preferably, the negative output terminal of the DC-DC isolated power supply is electrically connected to ground GND1.

[0024] This facilitates the normal operation of DC-DC isolated power supplies.

[0025] Preferably, the output voltage of the DC power input module CN0 is 24V.

[0026] When in use, the 24V power output from the DC power input module CN0 is converted to DC-DC isolation by connecting to a DC-DC isolation power supply, and outputs an isolated power supply that has no electrical connection to the input terminal.

[0027] In summary, the beneficial effects of this invention are as follows: Through the above structure, the technical solution of this application achieves complete electrical isolation between the input module of the low-voltage system and the front-end signal line in terms of power supply and signal path. It employs an independent dual-isolation circuit architecture combining power isolation and signal isolation. Through independent power isolation and signal isolation sections, synchronous electrical isolation of the power supply and signal of the input module of the low-voltage system is achieved, fundamentally cutting off the path of high-voltage signals propagating to the low-voltage system. This architecture is applicable to various low-voltage electronic systems such as FAS (Automatic Fire Alarm System), BAS (Building Automation System), and security systems, and has broad application value. Compared with existing technologies, the technical solution of this application replaces mechanical contact relays with fully electronic optocouplers and isolated power supplies, achieving faster response, longer lifespan, and higher isolation voltage. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a circuit structure for isolating input power and input signals according to the present invention. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0030] like Figure 1 As shown, a circuit structure for isolating input power and input signals includes a DC power input module CN0 and a signal input module CN1.

[0031] The positive terminal of the DC power input module CN0 is electrically connected to the positive input terminal of the DC-DC isolated power supply, and the negative terminal of the DC power input module CN0 is electrically connected to the negative input terminal of the DC-DC isolated power supply. In use, the DC power supply undergoes DC-DC isolation conversion via the DC-DC isolated power supply, outputting an isolated power supply with no electrical connection to the input terminal to power the signal isolation section, achieving a 1500V power isolation voltage. Specifically, the output voltage of the DC power input module CN0 is 24V. In use, the 24V power output from the DC power input module CN0 undergoes DC-DC isolation conversion via the DC-DC isolated power supply, outputting an isolated power supply with no electrical connection to the input terminal. Specifically, a fuse F0 and a diode D0 are electrically connected between the positive terminal of the DC power input module CN0 and the positive input terminal of the DC-DC isolated power supply. In use, the fuse F0 blows when the input current abnormally increases, providing overcurrent protection; the diode D0 cuts off in reverse when the input power supply polarity is reversed, providing reverse connection protection. The positive and negative output terminals of the DC-DC isolated power supply are electrically connected in series between a power indicator LED0 and a power indicator resistor R0. During operation, the illuminated power indicator LED0 indicates that the isolated power supply is functioning correctly, allowing maintenance personnel to quickly determine the device's power status. The negative output terminal of the DC-DC isolated power supply is electrically connected to ground GND1. This ensures the normal operation of the DC-DC isolated power supply.

[0032] The positive terminal of signal input module CN1 is electrically connected to the positive output terminal of the DC-DC isolated power supply, and the negative terminal of signal input module CN1 is electrically connected to the input anode of optocoupler U1. The input cathode of optocoupler U1 is electrically connected to the output negative terminal of the DC-DC isolated power supply. The collector and emitter of optocoupler U1 are electrically connected to signal output module CN9. In use, optocoupler U1 achieves electrical isolation of up to 5000 volts between input and output. The input electrical signal is converted into an optical signal and then restored to an electrical signal output; there is no direct electrical connection between the two circuits. A transient voltage suppression diode (TVS1) and a signal status indicator LED1 are connected in parallel between the input anode and input cathode of optocoupler U1. The signal status indicator resistor R102 is connected in series with the signal status indicator LED1. In use, the transient voltage suppression diode TVS1 clamps instantaneous high-voltage surges at the input terminal to a safe level, achieving overvoltage and surge protection; the signal status indicator LED1 lights up and turns off synchronously with the input side of optocoupler U1, clearly indicating the signal status of the current channel. A reverse polarity protection diode D1 is electrically connected between the emitter of optocoupler U1 and the signal output module CN9. During operation, the reverse polarity protection diode D1 ensures the correct polarity of the output signal, providing reverse polarity protection. An input fuse F1 is electrically connected between the input cathode of optocoupler U1 and the negative output terminal of the DC-DC isolated power supply. During operation, the input fuse F1 blows when the signal input current is abnormal, providing overcurrent protection. A short-circuit protection resistor R103 is electrically connected between the collector and emitter of optocoupler U1. During operation, the short-circuit protection resistor R103 prevents short circuits between the collector and emitter of optocoupler U1, improving safety. A resistor R101 is electrically connected between the input anode of optocoupler U1 and the signal input module CN1. During operation, the electrical connection resistor R101 prevents short circuits between the input anode and input cathode of optocoupler U1, improving safety.

[0033] Through the above structure, the technical solution of this application achieves complete electrical isolation between the input module of the low-voltage system and the front-end signal line in terms of power supply and signal path. It employs an independent dual-isolation circuit architecture combining power isolation and signal isolation. Through independent power isolation and signal isolation sections, synchronous electrical isolation of the power supply and signal of the input module of the low-voltage system is achieved, fundamentally cutting off the path of high-voltage signals propagating to the low-voltage system. This architecture is applicable to various low-voltage electronic systems such as FAS (Automatic Fire Alarm System), BAS (Building Automation System), and security systems, and has broad application value. Compared with existing technologies, the technical solution of this application replaces mechanical contact relays with fully electronic optocouplers and isolated power supplies, achieving faster response, longer lifespan, and higher isolation voltage; simultaneously, the circuit structure clearly integrates multiple protection and indication functions such as transient voltage suppression diodes, fuses, and status indicator lights.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A circuit structure for isolating input power and input signals, comprising a DC power input module CN0 and a signal input module CN1, characterized in that, The positive terminal of the DC power input module CN0 is electrically connected to the positive input terminal of the DC-DC isolated power supply, and the negative terminal of the DC power input module CN0 is electrically connected to the negative input terminal of the DC-DC isolated power supply. The positive terminal of signal input module CN1 is electrically connected to the positive output terminal of DC-DC isolated power supply, the negative terminal of signal input module CN1 is electrically connected to the input anode of optocoupler U1, the input cathode of optocoupler U1 is electrically connected to the negative output terminal of DC-DC isolated power supply, and the collector and emitter of optocoupler U1 are electrically connected to signal output module CN9.

2. The circuit structure for isolating input power and input signals as described in claim 1, characterized in that, The input anode and input cathode of the optocoupler U1 are electrically connected in parallel with a transient voltage suppression diode TVS1 and a signal status indicator LED1. The signal status indicator resistor R102 is connected in series with the signal status indicator LED1.

3. The circuit structure for isolating input power and input signals as described in claim 1, characterized in that, The emitter of optocoupler U1 is electrically connected to the reverse connection protection diode D1 between the signal output module CN9 and the optocoupler U1.

4. The circuit structure for isolating input power and input signals as described in claim 1, characterized in that, The collector and emitter of optocoupler U1 are electrically connected by a short-circuit protection resistor R103.

5. The circuit structure for isolating input power and input signals as described in claim 1, characterized in that, The input anode of optocoupler U1 is electrically connected to the signal input module CN1 by resistor R101.

6. The circuit structure for isolating input power and input signals as described in claim 1, characterized in that, The input cathode of optocoupler U1 is electrically connected to the output negative terminal of the DC-DC isolated power supply via input fuse F1.

7. The circuit structure for isolating input power supply and input signal as described in any one of claims 1 to 6, characterized in that, The positive terminal of the DC power input module CN0 is electrically connected to the positive input terminal of the DC-DC isolated power supply via fuse F0 and diode D0.

8. The circuit structure for isolating input power supply and input signal as described in any one of claims 1 to 6, characterized in that, The positive and negative output terminals of the DC-DC isolated power supply are electrically connected in series with a power indicator LED0 and a power indicator resistor R0.

9. The circuit structure for isolating input power supply and input signal as described in any one of claims 1 to 6, characterized in that, The negative output terminal of the DC-DC isolated power supply is connected to ground GND1.

10. The circuit structure for isolating input power supply and input signal as described in any one of claims 1 to 6, characterized in that, The output voltage of the DC power input module CN0 is 24V.

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