High-voltage dry reed relay of integrated drive circuit

Abstract

The invention discloses a high-voltage dry reed relay integrated with a driving circuit, the relay comprises a dry reed switch, a first shielding layer and a second shielding layer, the driving circuit and an isolating circuit are arranged in the relay, a control signal is transmitted to the dry reed switch through the isolating circuit and the driving circuit, and the first shielding layer and the second shielding layer are grounded. The reed switch is a normally open switch. The drive circuit is integrated in the dry reed relay, the circuit design is simplified, the problem of current leakage is solved through the two shielding layers, a control signal passes through the isolation circuit and the drive circuit to the dry reed switch, the dry reed switch is closed firstly, the voltage is gradually increased from low to high, the high voltage switching problem is effectively solved, and the reliability of the dry reed relay is improved. Epoxy resin is used as a packaging material, so that the protection performance, the stability and the reliability of the dry reed relay are improved. The integration level is high, the complexity of the whole circuit design is reduced, and the development time of the whole circuit is saved.

Description

Technical Field

[0001] The invention relates to a high-voltage reed relay with an integrated drive circuit. Background Art

[0002] High voltage reed relay is an electrical switch that uses the working principle of reed switch and is widely used in automation control, signal processing and circuit protection. Traditional high voltage reed relay provides driving signal through external circuit to control its on and off state. However, as the requirements of electronic equipment for integration, performance and reliability continue to increase, individual reed relays face some challenges.

[0003] The current use of high-voltage reed relays requires additional drive circuits, which increases the complexity of the overall circuit design. Engineers need to consider the selection, layout, and compatibility of the drive circuit with other components, which increases the design and development time to a certain extent; in traditional configurations, the efficiency of the drive circuit directly affects the performance of the reed relay. If the drive circuit design is unreasonable, it may cause excessive power consumption and affect the energy efficiency performance of the entire system. Due to the complexity of the external circuit, the system reliability of traditional reed relays is also affected. Each connection point in the circuit has a potential risk of failure, especially in high frequencies or harsh environments, which may cause malfunction or failure. In addition, as electronic devices develop towards miniaturization and lightweight, the problem of space occupied by additional drive circuits of traditional reed relays has become increasingly prominent. Especially in portable devices and compact designs, the effective use of limited space has become a major challenge in design. Summary of the invention

[0004] The present invention provides a high-voltage reed relay with an integrated drive circuit in order to solve the problems existing in the above-mentioned prior art.

[0005] The technical solutions adopted in the present invention are: A high-voltage reed relay with an integrated drive circuit, the relay comprising a reed switch, a first shielding layer and a second shielding layer, a drive circuit and an isolation circuit are arranged inside the relay, a control signal passes through the isolation circuit and the drive circuit to the reed switch, the first shielding layer and the second shielding layer are both grounded, and the reed switch is a normally open switch.

[0006] Furthermore, the driving circuit includes a resistor R5, a resistor R1, a voltage regulator D3, an N-channel field effect transistor, a coil L1, a freewheeling diode D4 and two diodes D1 and D2 connected in reverse series, the drain of the N-channel field effect transistor, the cathode of the voltage regulator D3 and the anode of the freewheeling diode D4 are connected together, one end of the coil L1 is externally connected to a VDDF power supply, the coil L1 is connected in parallel with the freewheeling diode D4, the source of the N-channel field effect transistor, the anode of the voltage regulator, the resistor R1 and the anode of the diode D2 are connected together and are externally connected to FG, the gate of the N-channel field effect transistor is connected to one end of the resistor R5, the cathode of the diode D1 and the cathode of the diode D2 are connected together, and the other end of the resistor R5, the other end of the resistor R1 and the anode of the diode D1 are connected together.

[0007] Furthermore, the isolation circuit includes a pull-up resistor R4, a resistor R2, a resistor R3 and an optocoupler U1, the pull-up resistor R4 and the collector of the phototransistor in the optocoupler U1 are connected to the drive circuit, the emitter of the phototransistor in the optocoupler U1 is externally connected to a VDDF power supply, the positive electrode of the light-emitting diode in the optocoupler U1 is connected to the resistor R2, the other end of the resistor R2 serves as a signal end to output a control signal, the negative electrode of the light-emitting diode is connected to one end of the resistor R3, and the other end of the resistor R3 is externally connected to FG.

[0008] Furthermore, the input port of the isolation circuit is connected to the signal end, and the input port of the drive circuit is connected to the output port of the isolation circuit to receive the isolated signal. When the signal end outputs the signal to the drive circuit, the drive circuit triggers the reed switch to close and the circuit is turned on.

[0009] Furthermore, the reed switch is a normally open switch, and when the circuit is working, the reed switch is in a normally conducting state.

[0010] The present invention has the following beneficial effects: The present invention simplifies the circuit design by integrating the drive circuit in the reed relay, solves the current leakage problem through two shielding layers, and the control signal passes through the isolation circuit and the drive circuit to the reed switch. The reed switch is closed first, and the voltage increases slowly from low to high, which effectively solves the high voltage switching problem. By using epoxy resin as the packaging material, the protection performance and stability and reliability of the reed relay are improved. The invention has a high degree of integration, reduces the complexity of the overall circuit design, and saves the development time of the overall circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a principle block diagram of the present invention.

[0012] Figure 2 This is the internal circuit structure diagram of a high voltage reed relay (two switch structures).

[0013] Figure 3 This is the internal circuit diagram of a high voltage reed relay (a switch structure). DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings.

[0015] like Figures 1 to 3 The present invention discloses a high-voltage reed relay with an integrated drive circuit. The relay comprises a reed switch, a first shielding layer and a second shielding layer. A drive circuit and an isolation circuit are arranged inside the relay.

[0016] The first shielding layer is connected to pin 9 of the high-voltage reed relay, and the second shielding layer is connected to pin 4 of the high-voltage reed relay and is also connected to FG.

[0017] Figure 3 This is the internal circuit diagram of a reed relay with a set of drive circuits controlling a set of switches. The principle is basically the same as that of two sets of switches, but compared Figure 2 The high voltage reed relay is missing a shielding layer.

[0018] The following is combined with Figure 2 Embodiments of the present invention will be described in detail.

[0019] The reed switch includes two sets of switches K1 and K2. Both sets of switches K1 and K2 are normally open switches. One end of the K1 switch is connected to pin 8 of the high-voltage reed relay. Pin 8 of the high-voltage reed relay is connected to a 6000V high-voltage signal.

[0020] One end of the K2 switch is connected to GDF through pin 7 of the high-voltage reed relay, the other end of K1 is connected to pin 1 of the reed switch and the output signal VHO, the other end of K2 is connected to pin 2 of the high-voltage reed relay, the second shielding layer is connected to pin 4 of the high-voltage reed relay, and pin 4 of the high-voltage reed relay is externally connected to FG.

[0021] The driving circuit includes two diodes D1 and D2 connected in reverse series, a resistor R5, a resistor R1, a voltage regulator D3, an N-channel field effect transistor, a control coil L1 and a freewheeling diode D4.

[0022] The drain of the N-channel field effect transistor, the cathode of the voltage regulator D3 and the anode of the freewheeling diode are connected together, and one end of the coil L1 is connected to the pin 5 of the reed switch and VDDF, and VDDF provides a 12V rated power supply.

[0023] One end of the coil L1 is connected to the cathode of the freewheeling diode D4, and the other end is connected to the driving circuit. The coil is connected in parallel with the freewheeling diode D4. The source of the N-channel field effect tube, the anode of the voltage regulator tube, the resistor R1, the anode of the diode D2, and the pin 3 of the high-voltage reed relay are connected together, and the pin 3 of the high-voltage reed relay is externally connected to FG. The gate of the N-channel field effect tube and one end of the resistor R5 are connected together, and the cathode of the diode D1 and the cathode of the diode D2 are connected together. The other end of the resistor R5, the other end of the resistor R1, and the anode of the diode D1 are connected together.

[0024] The purpose of the freewheeling diode D4 is that the inductive load will generate an induced electromotive force, and the direction of the induced electromotive force is opposite to the direction of the voltage applied across it. When the inductive load is suddenly powered off, the induced electromotive force is still there. Since the induced electromotive force is opposite to the original voltage, when the power is not cut off, there is still the original voltage to offset it. After the power is cut off, there is no voltage to offset the induced electromotive force. The induced electromotive force may cause damage to components in the circuit. After adding the freewheeling diode D4, the freewheeling diode D4 and the inductive load form a closed loop in the present invention. The current direction in the loop is exactly the same as the forward conduction of the freewheeling diode, so the current of the induced electromotive force can be released.

[0025] The isolation circuit includes a pull-up resistor R4, a resistor R2, a resistor R3 and an optocoupler U1. The pull-up resistor R4, the collector of the phototransistor in the optocoupler and the drive circuit are connected together through electrical signals, and the emitter of the phototransistor and pin 5 of the high-voltage reed relay are connected together to an external VDDF power supply.

[0026] The positive electrode of the light-emitting diode of the optical coupler U1 is connected to the resistor R2, and the other end of the resistor R2 is used as a signal end to output the control signal. The negative electrode of the light-emitting diode is connected to the resistor R3, and the other end of the resistor R3 is connected to the pin 3 of the high-voltage reed relay and externally connected to FG.

[0027] The switch K1 and the switch K2 in the reed switch are two sets of normally open switches. When the circuit is working, the reed switch is in a normally conducting state.

[0028] The input port of the isolation circuit is connected to the signal end, and the input port of the drive circuit is connected to the output port of the isolation circuit to receive the isolated signal; when the signal end outputs the signal to the drive circuit, when the G end signal is greater than V GND +V GS MOS tube U3 is turned on when the signal voltage is less than V GND +V GS When the MOS tube U3 is turned on, the drive circuit triggers the two sets of switches of the reed switch to close, and the circuit is turned on.

[0029] Specifically, the reed switch voltage is VDDF = 12V, the rated voltage of the coil is 5V, and the drain-source voltage is: V DS =12-5=7V. Threshold voltage V GS(th) =1.2V, when the driving voltage is greater than the threshold voltage, the MOS tube U3 is turned on, that is: V GS >1.2V.

[0030] When the signal is sent to the input of the optocoupler, the light-emitting diode emits light through the current, and the phototransistor generates current and turns on after being illuminated by light; when there is no signal at the input, the light-emitting diode does not light up, and the phototransistor is cut off; when the input is a high level "1", the phototransistor is saturated and turned on, and the output is a low level "0", V GS =0V; when the input is low level "0", the phototransistor is cut off and the output is high level "1". The rated voltage VDDF is 12V, and the pull-up resistor R4 and the pull-down resistor R1 are both 300kΩ, and the voltage is divided to get V GS Voltage: V GS =6V.

[0031] At this time V GS >V GS(th) , Mos tube U3 is turned on normally and the circuit works normally.

[0032] Based on the above solution, there are two layers of signal shielding inside the reed switch. The first shielding layer is connected to FG of the reed switch housing, and the second shielding layer is connected to GDF. The leakage current is effectively eliminated through the two layers of shielding.

[0033] One set of switches of the reed switch is connected to the output signal VHO terminal, and another set of switches is connected to the GDF terminal.

[0034] The contact surface of the reed switch is plated with a layer of tungsten. Unlike other materials, tungsten is low in cost and has an extremely high melting point and excellent arc resistance, which improves the voltage resistance level between the contacts.

[0035] Epoxy resin is used as the packaging material of the reed relay to improve the protection performance and stability and reliability of the reed relay.

[0036] The control signal passes through the isolation circuit and the drive circuit to the reed switch. At this time, the reed switch is closed, and the voltage slowly increases from low to high, and the high voltage is output through pin 1 of the high-voltage reed relay.

[0037] When the control signal disappears, the voltage slowly decreases from high to low. When the voltage between the contacts reaches the withstand voltage, the reed switch gradually disconnects.

[0038] Based on the above scheme, the creepage distance is related to the comparative tracking index (CTI) of the insulating material and the environmental pollution level. The higher the CTI level of the material, the shorter the creepage distance can be. Conversely, the lower the environmental pollution level, the shorter the creepage distance can be. Under the conditions of 6000V DC working voltage (equivalent to 4243VAC), pollution level 1, and CTI of 600, according to the IEC 60664-1 standard, the minimum creepage distance required is about 4mm.

[0039] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A high voltage reed relay with integrated drive circuit, characterized in that: The relay includes a reed switch, a first shielding layer and a second shielding layer. A drive circuit and an isolation circuit are provided inside the relay. The control signal passes through the isolation circuit and the drive circuit to the reed switch. The first shielding layer and the second shielding layer are both grounded. The reed switch is a normally open switch.

2. The high voltage reed relay with integrated drive circuit as claimed in claim 1, characterized in that: The driving circuit includes a resistor R5, a resistor R1, a voltage regulator D3, an N-channel field effect transistor, a coil L1, a freewheeling diode D4 and two diodes D1 and D2 connected in reverse series. The drain of the N-channel field effect transistor, the cathode of the voltage regulator D3 and the anode of the freewheeling diode D4 are connected together, one end of the coil L1 is externally connected to a VDDF power supply, the coil L1 is connected in parallel with the freewheeling diode D4, the source of the N-channel field effect transistor, the anode of the voltage regulator, the resistor R1 and the anode of the diode D2 are connected together and are externally connected to FG, the gate of the N-channel field effect transistor is connected to one end of the resistor R5, the cathode of the diode D1 and the cathode of the diode D2 are connected together, and the other end of the resistor R5, the other end of the resistor R1 and the anode of the diode D1 are connected together.

3. The high voltage reed relay with integrated drive circuit as claimed in claim 1, characterized in that: The isolation circuit includes a pull-up resistor R4, a resistor R2, a resistor R3 and an optocoupler U1. The pull-up resistor R4 and the collector of the phototransistor in the optocoupler U1 are connected to the drive circuit. The emitter of the phototransistor in the optocoupler U1 is externally connected to a VDDF power supply. The positive electrode of the light-emitting diode in the optocoupler U1 is connected to the resistor R2. The other end of the resistor R2 serves as a signal end to output a control signal. The negative electrode of the light-emitting diode is connected to one end of the resistor R3. The other end of the resistor R3 is externally connected to FG.

4. The high voltage reed relay with integrated drive circuit as claimed in claim 1, characterized in that: The input port of the isolation circuit is connected to the signal end, and the input port of the drive circuit is connected to the output port of the isolation circuit to receive the isolated signal. When the signal end outputs the signal to the drive circuit, the drive circuit triggers the reed switch to close and the circuit is turned on.

5. The high voltage reed relay with integrated drive circuit as claimed in claim 1, characterized in that: The reed switch is a normally open switch. When the circuit is working, the reed switch is in a normally conducting state.

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