High-voltage-resistant ac-dc in-situ detection circuit
By combining relays and optocouplers, the problem of solid-state relays being easily damaged in inductive systems is solved, enabling stable detection of high-voltage AC/DC signals and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SYNTRONIC (BEIJING) TECH R&D CENT CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-06-05
AI Technical Summary
Existing solid-state relays are susceptible to damage from induced electromotive force in inductive systems, are costly, and cannot effectively detect high-voltage AC/DC signals.
By employing a combination of relays, discrete diodes, and optocouplers, a bridge rectifier and filter capacitor are formed through series diodes, which improves the withstand voltage and enables AC/DC signal detection compatibility.
It broadens the application range of the detection circuit, improves the withstand voltage, reduces material costs, and can effectively detect positive and negative high voltages generated by inductive loads.
Smart Images
Figure CN224328208U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of hardware circuit technology, specifically to a high-voltage AC / DC in-situ detection circuit. Background Technology
[0002] With the rapid development of the electronics industry, people's needs are becoming increasingly diversified. When it is necessary to control high voltage with low voltage through MCU or PLC, isolation detection devices are required.
[0003] Currently, solid-state relays are commonly used for testing. However, solid-state relays generally have low voltage withstand capability and are relatively expensive. For resistive systems, this method is functionally sound.
[0004] However, if an inductive system is encountered, the solid-state relay may be damaged due to insufficient withstand voltage. This is because an inductive system generates a large induced electromotive force when the load changes abruptly. Therefore, a high-voltage AC / DC in-situ detection circuit is designed to solve this problem. Utility Model Content
[0005] The purpose of this invention is to provide a high-voltage AC / DC in-situ detection circuit to solve the problems mentioned in the background art.
[0006] To achieve the above objectives, this utility model provides the following technical solution: a high-voltage AC / DC in-situ detection circuit, comprising a relay J1, diodes D1, D2, D3, D4, D5, D6, and D7, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10, a capacitor C1, an optocoupler U1, and a relay J2. The PIN2 of the relay J1 is connected to the PIN1 of the optocoupler U1 via diodes D1, D2, R1, R2, R3, R4, R5, R6, and R7. The PIN1 of the relay J1 is connected between diode D2 and resistor R1 via diodes D8 and D9.
[0007] Diodes D3 and D4 are connected in series, with their cathodes connected to PIN2 of relay J1 and their anodes grounded; diodes D5 and D6 are connected in series, with their cathodes grounded and their anodes connected to PIN2 of relay J1; resistors R9 and R10 are connected in series, with one end grounded and the other end connected between resistors R5 and R6; PIN1 of relay J2 is connected to PIN2 of relay J2 in sequence through resistor R8, PIN4 of optocoupler U1, and PIN3; the anode of diode D7 is connected to PIN2 of relay J2, and its cathode is connected to PIN4 of optocoupler U1.
[0008] Preferably, the PIN2 of the optocoupler U1 is grounded.
[0009] Preferably, one end of the capacitor C1 is grounded, and the other end is connected between resistors R5 and R6.
[0010] Compared with the prior art, the beneficial effects of this utility model are:
[0011] 1. It broadens the application range of the detection circuit, including resistive and inductive loads, and AC and DC power supplies.
[0012] 2. Improve the voltage withstand capability of the detection circuit to prevent damage.
[0013] 3. Reduced material costs.
[0014] This invention improves the voltage withstand capability of the detection circuit by using discrete components in series. Through the reasonable combination of rectifier bridge and filter capacitor, it achieves AC and DC detection compatibility and can withstand high voltage in both positive and negative directions generated by inductive load. Attached Figure Description
[0015] Figure 1 Functional module block diagram;
[0016] Figure 2 This is a simulation diagram of the high voltage at the moment of shutdown.
[0017] Figure 3 This is the circuit diagram of this utility model;
[0018] Figure 4 This is a functional simulation diagram of the present invention. Detailed Implementation
[0019] 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.
[0020] This invention proposes a method that combines high-voltage-resistant devices with optocouplers to acquire AC / DC signals and then transmit the signals to an MCU or PLC. This achieves the detection purpose without damaging the corresponding devices due to the high voltage from the inductive system.
[0021] See Figure 1 When AC / DC power is supplied to an inductive load, a high voltage will be generated across the load the instant the switch is turned off. The direction of the high voltage may be positive or negative.
[0022] See Figure 2 At the moment the switch is turned off, the voltage across the inductive load is already as high as 1400V. If a solid-state relay is used for detection, the coil side of the solid-state relay can mostly only withstand a voltage of less than 400V. 1400V is enough to damage the solid-state relay.
[0023] See Figure 3 This utility model provides a technical solution: a high-voltage AC / DC in-situ detection circuit, including a relay J1, diodes D1, D2, D3, D4, D5, D6, and D7, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10, a capacitor C1, an optocoupler U1, and a relay J2. The PIN2 of the relay J1 is connected to the PIN1 of the optocoupler U1 via diodes D1, D2, R1, R2, R3, R4, R5, R6, and R7. The PIN1 of the relay J1 is connected between diode D2 and resistor R1 via diodes D8 and D9.
[0024] Diodes D3 and D4 are connected in series, with their cathodes connected to PIN2 of relay J1 and their anodes grounded; diodes D5 and D6 are connected in series, with their cathodes grounded and their anodes connected to PIN2 of relay J1; resistors R9 and R10 are connected in series, with one end grounded and the other end connected between resistors R5 and R6; PIN1 of relay J2 is connected to PIN2 of relay J2 via resistor R8, PIN4 of optocoupler U1, and PIN3; the anode of diode D7 is connected to PIN2 of relay J2, and its cathode is connected to PIN4 of optocoupler U1, with PIN2 of optocoupler U1 grounded; one end of capacitor C1 is grounded, and the other end is connected between resistors R5 and R6.
[0025] This design uses discrete components, and improves the withstand voltage by connecting the components in series. At the same time, the selected discrete components are all general-purpose components, which are inexpensive and easy to obtain.
[0026] 1) A bridge rectifier is built by separating diodes. Each bridge arm uses two 1kV diodes connected in series. The voltage withstand of the entire rectifier bridge circuit is increased to 2kV. Regardless of whether the generated high voltage is positive or negative, it is rectified into positive voltage after passing through the rectifier bridge. Therefore, this design can withstand high voltage in both positive and negative directions.
[0027] 2) Detection section: The instantaneous withstand voltage of ordinary 1206 resistors is 400V. Multiple 1206 resistors are connected in series to increase the withstand voltage. When the detection input voltage is AC, the C1 capacitor acts as a filter to make the light at the input of the optocoupler stable, so that the detection signal of the subsequent stage is stable.
[0028] 3) Functional simulation, such as Figure 4 As shown, when the switch is closed, there is AC power across the load terminals, and the detection signal is high; when the switch is open, there is no AC power across the load terminals, and the detection signal is low.
[0029] This invention improves the voltage withstand capability of the detection circuit by using discrete components in series. Through the reasonable combination of rectifier bridge and filter capacitor, it achieves AC and DC detection compatibility and can withstand high voltage in both positive and negative directions generated by inductive load.
[0030] The contents not described in detail in this specification are prior art known to those skilled in the art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A high-voltage AC / DC in-situ detection circuit, characterized in that: The system includes a relay J1, diodes D1, D2, D3, D4, D5, D6, and D7, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10, a capacitor C1, an optocoupler U1, and a relay J2. The pin 2 of the relay J1 is connected to the pin 1 of the optocoupler U1 via diodes D1, D2, R1, R2, R3, R4, R5, R6, and R7. The pin 1 of the relay J1 is connected between diode D2 and resistor R1 via diodes D8 and D9. Diodes D3 and D4 are connected in series, with their cathodes connected to PIN2 of relay J1 and their anodes grounded; diodes D5 and D6 are connected in series, with their cathodes grounded and their anodes connected to PIN2 of relay J1; resistors R9 and R10 are connected in series, with one end grounded and the other end connected between resistors R5 and R6; PIN1 of relay J2 is connected to PIN2 of relay J2 in sequence through resistor R8, PIN4 of optocoupler U1, and PIN3; the anode of diode D7 is connected to PIN2 of relay J2, and its cathode is connected to PIN4 of optocoupler U1.
2. The high-voltage AC / DC in-situ detection circuit according to claim 1, characterized in that: The PIN2 of the optocoupler U1 is grounded.
3. The high-voltage AC / DC in-situ detection circuit according to claim 1, characterized in that: One end of the capacitor C1 is grounded, and the other end is connected between resistors R5 and R6.