Low-current signal isolation output circuit and device

Abstract

The utility model discloses a low current signal isolation output circuit and device, and relates to the isolation device technology field, the low current signal isolation output circuit comprises an input loop, an isolation optocoupler, a relay, an auxiliary contact, an isolation weak current loop and a CPU controller, the input loop comprises a DC220V input loop and a DC110V input loop, the input loop is connected with the diode side of the isolation optocoupler, the relay is connected with the isolation optocoupler, and the isolation optocoupler is connected with the relay. A diode is connected after passing through the diode; a diode input end of the isolation optocoupler is connected in parallel with a resistor and a ceramic capacitor, and an output end of the isolation optocoupler is connected with a coil of the relay; and a coil of the relay is connected with a power supply DC24V. The low-current signal isolation output circuit and device have a stable electrical isolation effect, reduce the power consumption of the circuit, reduce the heat productivity, and improve the anti-interference capability of the circuit at the same time.

Description

Technical Field

[0001] This utility model relates to the field of isolation device technology, and more specifically to a small current signal isolation output circuit and device. Background Technology

[0002] In power systems, relay protection operating circuits, as the core component for realizing the response of protection devices, primarily function to: once the triggering conditions for protection action are detected, execute commands to connect or disconnect associated circuits to quickly isolate faulty areas and ensure the safe and stable operation of equipment and systems. Furthermore, by increasing contact capacity, damage to protection output contacts due to overload is effectively avoided.

[0003] However, in the current power distribution field, for some non-electrical input signal processing, many relays still use the traditional method of directly connecting them in series with the main circuit. In this configuration, to maintain normal circuit operation, a continuous current of tens of milliamps is required. This not only leads to significant heating effects from internal circuit resistance and relays, but also necessitates an efficient heat dissipation mechanism for the operating circuit. Furthermore, the large operating current makes the system more sensitive to strong external electromagnetic interference, increasing the risk of hardware damage due to interference. Any failure in the input signal circuit could pose a significant threat to the safety and reliability of the power grid.

[0004] Therefore, it is necessary to propose a low-current signal isolation circuit and device to solve the above problems. Utility Model Content

[0005] To address the above problems, this utility model provides a low-current signal isolation output circuit and device, which provides electrical isolation and improves anti-interference capability.

[0006] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0007] A low-current signal isolation output circuit and device includes an input circuit, an isolation optocoupler, a relay, auxiliary contacts, an isolation low-voltage circuit, and a CPU controller;

[0008] The input circuit includes a DC220V input circuit and a DC110V input circuit. The input circuit is connected to the diode side of the isolation optocoupler, and after passing through the diode, it is connected to diode D1.

[0009] The diode input terminal of the isolation optocoupler is connected in parallel with a resistor R5 and a ceramic capacitor C2, and the output terminal of the isolation optocoupler is connected to the coil of the relay.

[0010] The relay coil is connected to a DC24V power supply, and a diode D2 is connected in parallel across the relay coil. One auxiliary contact of the relay is connected to a terminal P2, and a varistor Y is connected in parallel across terminal P2. The other auxiliary contact of the relay is connected to an isolated low-voltage circuit.

[0011] The isolated low-voltage circuit includes a power supply VDD3.3, which is connected to the CPU controller;

[0012] A capacitor C1 is connected in parallel to the auxiliary contact of the relay.

[0013] Preferably, the DC220V input circuit includes resistors R1 and R2 connected in series at the input port.

[0014] Preferably, the DC110V input circuit includes resistors R3 and R4 connected in series at the input port.

[0015] Preferably, a resistor R6 is connected between the power supply VDD3.3 and the CPU controller.

[0016] Preferably, a resistor R7 is connected between the relay coil and the DC24V power supply.

[0017] A low-current signal isolation output device includes a main board and a housing. The main board is installed inside the housing, and a display panel and control buttons are installed on the housing. The main board, display panel and buttons are electrically connected.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] 1. This device, by placing the intermediate relay on the secondary side of the isolation optocoupler, enables the use of a small signal from the primary side of the optocoupler to control the relay's operation. This not only enhances the system's anti-interference performance but also ensures effective electrical isolation between the primary and secondary sides of the relay through the application of relay auxiliary contacts to feed back to the primary circuit, thereby improving the system's safety and reliability.

[0020] 2. This relay drive circuit design is compatible with DC110V and DC220V DC voltage input, which improves the adaptability of input voltage. The low drive current requirement reduces the power consumption of the drive circuit and also reduces heat generation. It also helps to reduce the overall size of the device and improve the system integration. At the same time, the low current drive characteristics also help to extend the service life of the relay contacts and other related components.

[0021] 3. An anti-interference scheme has been added to the optocoupler side. The resistor and capacitor connected in parallel on the optocoupler side absorb interference signals in the circuit, improving the anti-interference capability. The directional diode at the negative end of the circuit prevents the signal from being connected in reverse, thus protecting the circuit. Attached Figure Description

[0022] Figure 1 This is a circuit block diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the control principle in this utility model;

[0024] Figure 3 This is a cross-sectional view of the small current signal isolation output device of this utility model;

[0025] Figure 4 This is a front view of the small current signal isolation output device of this utility model.

[0026] Figure label:

[0027] 101. Input circuit; 102. Isolation optocoupler; 103. Relay; 104. Auxiliary contact; 105. Isolation low-voltage circuit; 106. CPU controller; 107. Main board; 108. Housing; 109. Display board; 110. Control button. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Please see Figure 1-4 A low-current signal isolation output circuit and device includes an input circuit 101, an isolation optocoupler 102, a relay 103, an auxiliary contact 104, an isolation low-voltage circuit 105, and a CPU controller 106.

[0030] refer to Figure 1 and Figure 2 The input circuit 101 includes a DC220V input circuit and a DC110V input circuit. The input circuit 101 is connected to the diode side of the isolation optocoupler 102. After passing through the diode, a diode D1 is connected. The input terminal of the isolation optocoupler 102 on the drive side of the relay 103 is composed of resistors R1 and R2 forming a DC220V input circuit and resistors R3 and R4 forming a DC110V input circuit. After the two circuits drive the diode on the input side of the optocoupler, they form a circuit after passing through the directional diode D1.

[0031] refer to Figure 1 and Figure 2The diode input terminal of the isolation optocoupler 102 is connected in parallel with a resistor R5 and a ceramic capacitor C2. The isolation optocoupler 102 is input to the acquisition circuit to form a long-term small current continuous signal. The parallel resistor R5 is used to shunt and absorb interference signals, and the parallel capacitor C2 can bypass interference signals to protect the input port. The output terminal of the isolation optocoupler 102 is connected to the coil of the relay 103. The relay 103 (reference) Figure 2 K1 in the figure is driven by the output of the isolation optocoupler 102;

[0032] refer to Figure 1 and Figure 2 The coil of relay 103 is connected to a DC24V power supply. The coil of relay 103 is connected to the DC24V power supply after being connected in series with a current-limiting resistor R7. The coil of relay 103 is driven by the secondary side of an optocoupler and has no external interference signal. A diode D2 is connected in parallel across the coil of relay 103 to prevent reverse interference signals after the coil of relay 103 is de-energized and to consume the reverse energy of the coil of relay 103. One auxiliary contact 104 of relay 103 is connected to terminal P2. The auxiliary contact 104 of relay 103 (K1) is connected to terminal P2 for external use. A varistor Y is connected in parallel across terminal P2. In order to prevent external strong electric interference, a varistor Y is connected in parallel across the auxiliary contact 104. It can quickly discharge high-frequency interference energy and protect the downstream circuit. The other auxiliary contact 104 of relay 103 is connected to the isolated weak current circuit 105. The CPU controller 106 collects the relay 103 action signal DI4.

[0033] refer to Figure 2 The isolated low-voltage circuit 105 includes a power supply VDD3.3, which is connected to the CPU controller 106. The VDD3.3 power supply, resistor R6, auxiliary contact 104 and capacitor C1 are connected together.

[0034] refer to Figure 2 A capacitor C1 is connected in parallel to the auxiliary contact 104 of the relay 103 to absorb interference signals introduced when the contact is frequently switched on and off.

[0035] Specifically, refer to Figure 2 The DC220V input circuit includes resistors R1 and R2 connected in series at the input port, which serve to protect the DC220V input circuit.

[0036] Specifically, refer to Figure 2 The DC110V input circuit includes resistors R3 and R4 connected in series at the input port, which serve to protect the DC110V input circuit.

[0037] Specifically, refer to Figure 2A resistor R6 is connected between the power supply VDD3.3 and the CPU controller 106. When the auxiliary contact 104 is open, the VDD3.3 power supply and the resistor R6 form an open circuit, so the DI4 level signal is high, and the CPU controller 106 can normally acquire the high level signal. When the auxiliary contact 104 is closed, the VDD3.3 power supply and the resistor R6 close the auxiliary contact 104, forming a circuit, so the DI4 level signal is low, and the CPU controller 106 can normally acquire the low level signal.

[0038] Specifically, refer to Figure 2 A resistor R7 is connected between the coil of the relay 103 and the DC24V power supply.

[0039] A low-current signal isolation output device, reference Figure 3 and Figure 4 The device includes a motherboard 107 and a housing 108. The motherboard 107 is installed inside the housing 108, which protects the motherboard 107 and also secures it to other equipment structures. A display panel 109 and control buttons 110 are installed on the housing 108. The motherboard 107, display panel 109, and buttons are electrically connected. The control buttons 110 are used to control the motherboard 107, and the display panel 109 is used to display the status of the motherboard 107.

[0040] In this embodiment, the relay 103 supports two voltage specifications: DC220V and DC110V for its drive input. By using a resistor voltage divider network, the input voltage of different levels is adjusted to a voltage range suitable for the coupler's operation, ensuring complete electrical isolation between high-voltage and low-voltage circuits. This effectively improves the safety and stability of the system and allows for extremely low input current (as low as 1mA), further enhancing this isolation effect. This protects the control system from external circuit noise interference. To enhance anti-interference performance, an absorption circuit consisting of resistors and capacitors is connected in parallel on the input side of the optocoupler, which can effectively filter out potential interference signals.

[0041] When relay 103 operates, its auxiliary contact 104 closes, connecting to the low level of the reference terminal. At this time, the CPU controller 106 detects a low-level signal. Conversely, if relay 103 does not operate, the auxiliary contact 104 remains open, connecting to the power supply terminal (high level), causing the CPU to detect a high-level signal. This not only enables precise monitoring of the operating status of relay 103, but also provides reliable contact output for external devices to meet further application needs. It has the functions of electrical isolation, anti-interference measures, and status feedback.

[0042] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A low-current signal isolation output circuit, characterized in that: This includes input circuits, isolation optocouplers, relays, auxiliary contacts, isolated low-voltage circuits, and the CPU controller; The input circuit includes a DC220V input circuit and a DC110V input circuit. The input circuit is connected to the diode side of the isolation optocoupler, and after passing through the diode, it is connected to diode D1. The diode input terminal of the isolation optocoupler is connected in parallel with a resistor R5 and a ceramic capacitor C2, and the output terminal of the isolation optocoupler is connected to the coil of the relay. The relay coil is connected to a DC24V power supply, and a diode D2 is connected in parallel across the relay coil. One auxiliary contact of the relay is connected to a terminal P2, and a varistor Y is connected in parallel across terminal P2. The other auxiliary contact of the relay is connected to an isolated low-voltage circuit. The isolated low-voltage circuit includes a power supply VDD3.3, which is connected to the CPU controller; A capacitor C1 is connected in parallel to the auxiliary contact of the relay.

2. The low-current signal isolation output circuit according to claim 1, characterized in that: The DC220V input circuit includes resistors R1 and R2 connected in series at the input port.

3. The low-current signal isolation output circuit according to claim 2, characterized in that: The DC110V input circuit includes resistors R3 and R4 connected in series at the input port.

4. The low-current signal isolation output circuit according to claim 3, characterized in that: A resistor R6 is connected between the power supply VDD3.3 and the CPU controller.

5. The low-current signal isolation output circuit according to claim 4, characterized in that: A resistor R7 is connected between the relay coil and the DC24V power supply.

6. A low-current signal isolation output device, wherein a low-current signal isolation output circuit of claim 5 is installed thereon, characterized in that: It includes a motherboard and a housing, the motherboard being installed inside the housing, and a display panel and control buttons being installed on the housing, the motherboard, display panel and buttons being electrically connected.

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