A driving circuit for quick closing and releasing of a bootstrap double voltage relay

Abstract

The invention discloses a driving circuit for fast closing and releasing of a bootstrap double voltage relay, wherein a resistor R7 is connected to a diode D2, a diode D3, a diode D2 and a transistor Q3 are connected, a diode D1 is connected to a relay K1, a capacitor C2 is connected to the relay K1, a power supply VCC is connected to the resistors R1 and R6, a resistor R5 is connected to the transistor Q2, a diode D1, a transistor Q3 and a transistor Q1 are connected to the power supply VCC, a resistor R2, a driving signal SW and the transistor Q1 are connected, a resistor R1 is connected to the transistor Q1 and the resistor R2, the transistor Q2 is connected to the resistor R4 and the capacitor C1, a voltage regulator D5 is connected to the transistor Q2, a voltage regulator D4 is connected to the voltage regulator D5, the voltage regulator D4 is connected to the lower end of the relay K1, and the lower end of the relay K1 is connected to the transistor Q2, thereby solving the problem that the relay connection and disconnection speed is slow and the output circuit cannot be effectively protected in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a driving circuit for a bootstrap double-voltage relay to quickly pull in and release. Background Art

[0002] Electromagnetic relay (hereinafter referred to as "relay") is an electronic control device, which has a control system (coil side input circuit) and a controlled system (contact side output circuit), and is usually used in automatic control circuits. It is a switch control method that uses a smaller current and a lower voltage to control a larger current and a higher voltage. It plays the role of automatic regulation, safety protection, and circuit conversion in the circuit, and can realize remote control and production automation.

[0003] Conventional relay driving technology cannot achieve the slow closing and disconnecting speed of its contact side, especially in situations where high-speed and high-frequency coordination are required, resulting in the relay contacts being unable to switch quickly, thus affecting the performance of the output circuit and the life of the relay. The closing speed of the relay contacts is related to the voltage rate at both ends of the coil. The larger the voltage rate, the faster the closing speed; and the speed at which the relay contacts bounce open is related to the consumption time of the induced current when the relay coil is turned off. The shorter the consumption time, the faster the relay contacts bounce open. In addition, the induced current generated when the relay coil is turned off is also a key issue of concern. The induced current is caused by the self-inductance effect when the relay coil voltage suddenly decreases, which will cause damage to the circuit and needs to be processed. Summary of the invention

[0004] In view of the problem in the prior art that the contact side of the relay is slow to close and disconnect and cannot effectively protect the output circuit, the present invention adopts the following solution:

[0005] A driving circuit for a bootstrap double-voltage relay to quickly pull in and release, the circuit structure is as follows:

[0006] One end of the resistor R7 is grounded, and the other end is connected to the cathode of the diode D2. The cathode of the diode D3 is connected to the anode of the diode D2. The anode of the diode D3 is connected to the collector of the transistor Q3. The emitter of the transistor Q3 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the upper end of the coil side of the relay K1. One end of the capacitor C2 is connected between the resistor R7 and the diode D2, and the other end is connected to the upper end of the coil side of the relay K1. One end of the resistor R1 is connected to the power supply VCC. One end of the resistor R6 is connected to the power supply VCC. The other end of the resistor R6 is connected to the resistor R5. The other end of the resistor R5 is connected to the collector of the transistor Q2. The base of the transistor Q3 is connected between the resistor R5 and the resistor R6. The anode of the diode D1, the emitter of the transistor Q3, The emitter of transistor Q1 is connected to the power supply VCC, one end of resistor R2 is connected to the driving signal SW, and one end is connected to the base of transistor Q1, the other end of resistor R1 is connected between the base of transistor Q1 and resistor R2, resistor R3 is connected between the collector of transistor Q1 and resistor R4, the base of transistor Q2 is connected to resistor R4 and one end of capacitor C1, the emitter of transistor Q2 is connected to the other end of resistor R4 and capacitor C1, the anode of Zener diode D5 is connected to the emitter of transistor Q2, a grounding mechanism is provided between the anode of Zener diode D5 and the emitter of transistor Q2, the anode of Zener diode D4 is connected to the cathode of Zener diode D5, the cathode of Zener diode D4 is connected to the lower end of the coil side of relay K1, and the lower end of the coil side of relay K1 is connected to the collector of transistor Q2.

[0007] Preferably, when the driving signal SW is at a high level, the transistors Q1, Q2, and Q3 are disconnected, and the diode D1 is forward-conducted. At this time, the power supply VCC charges the capacitor C2 through the diode D1.

[0008] Preferably, when the driving signal SW is at a high level, the relay K1 is in a non-operating state, and the contact side remains normally closed.

[0009] Preferably, when the driving signal SW changes from a low level to a high level, the induced current on the coil side of the relay K1 is released quickly, so that the contact side returns to a normally closed state, and the output circuit is connected.

[0010] Preferably, when the driving signal SW is at a low level, the transistor Q1 is turned on, causing the transistor Q2 to be turned on and the transistor Q3 to be turned on, and the voltage of the power supply VCC is added to the upper end of the capacitor C2 through the transistor Q3, the diode D3 and the diode D2.

[0011] Preferably, since the voltage of capacitor C2 cannot change suddenly, the voltage at the lower end of capacitor C2 is also the voltage at the upper end of the coil side of relay K1, which reaches twice the voltage of VCC. The unidirectional characteristic of diode D1 prevents the double voltage from flowing to VCC.

[0012] Preferably, when the voltage at the lower end of capacitor C2 and the voltage at the upper end of the coil side of relay K1 reach twice the voltage of VCC, the lower end of the coil side of relay K1 is grounded through the turned-on transistor Q2. Since the capacitor voltage cannot change suddenly, the voltage difference between the upper and lower ends of the coil side of relay K1 is twice the voltage of VCC, and the contacts of relay K1 can quickly close and open.

[0013] Preferably, diode D3 and diode D2 are Schottky diodes, which have a smaller conduction voltage and a lower switching capacitance, so that the circuit conducts faster.

[0014] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0015] 1. Use transistor Q3, diode D3, diode D2, and diode D1 to add 2 times VCC voltage to both ends of the coil side of relay K1, so as to quickly disconnect the contact side of relay K1 and protect the output circuit.

[0016] 2. Use resistors R6, R5 and diode D1 to quickly consume the induced current on the coil side of relay K1, use Zener diodes D4 and D5 to clamp the lower end of the coil side of relay K1 to protect the collector of transistor Q3, achieve rapid release of the voltage on the coil side of relay K1, and rapid closure of the contact side of relay K1, thereby ensuring circuit safety and the reliability of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of a driving circuit for a bootstrap double-voltage relay to quickly pull in and release according to the present invention;

[0019] Figure 2 is a circuit diagram of an embodiment of the present invention;

[0020] Figure 3 It is a circuit diagram of prior art 1;

[0021] Figure 4 It is a circuit diagram of prior art 2;

[0022] Figure 5 is a simulation waveform diagram of an embodiment of the present invention;

[0023] Figure 6 It is a simulation waveform diagram of prior art 1;

[0024] Figure 7 It is the simulation waveform diagram of prior art 2. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it may not be further defined or explained in the subsequent drawings.

[0027] Embodiment 1:

[0028] like Figure 1 As shown,

[0029] A driving circuit for a bootstrap double-voltage relay to quickly pull in and release, the circuit structure is as follows:

[0030] One end of the resistor R7 is grounded, and the other end is connected to the cathode of the diode D2. The cathode of the diode D3 is connected to the anode of the diode D2. The anode of the diode D3 is connected to the collector of the transistor Q3. The emitter of the transistor Q3 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the upper end of the coil side of the relay K1. One end of the capacitor C2 is connected between the resistor R7 and the diode D2, and the other end is connected to the upper end of the coil side of the relay K1. One end of the resistor R1 is connected to the power supply VCC. One end of the resistor R6 is connected to the power supply VCC. The other end of the resistor R6 is connected to the resistor R5. The other end of the resistor R5 is connected to the collector of the transistor Q2. The base of the transistor Q3 is connected between the resistor R5 and the resistor R6. The anode of the diode D1, the emitter of the transistor Q3, The emitter of transistor Q1 is connected to the power supply VCC, one end of resistor R2 is connected to the driving signal SW, and one end is connected to the base of transistor Q1, the other end of resistor R1 is connected between the base of transistor Q1 and resistor R2, resistor R3 is connected between the collector of transistor Q1 and resistor R4, the base of transistor Q2 is connected to resistor R4 and one end of capacitor C1, the emitter of transistor Q2 is connected to the other end of resistor R4 and capacitor C1, the anode of Zener diode D5 is connected to the emitter of transistor Q2, a grounding mechanism is provided between the anode of Zener diode D5 and the emitter of transistor Q2, the anode of Zener diode D4 is connected to the cathode of Zener diode D5, the cathode of Zener diode D4 is connected to the lower end of the coil side of relay K1, and the lower end of the coil side of relay K1 is connected to the collector of transistor Q2.

[0031] When the drive signal SW is at a high level (working level), transistors Q1, Q2, and Q3 are disconnected, and diode D1 is forward-conducted. At this time, the power supply VCC charges capacitor C2 to 11.3V through diode D1.

[0032] When the drive signal SW is at a high level, the power supply VCC also reaches the ground through the emitter and base of the transistor Q3, the resistor R5, the Zener diode D4 and the Zener diode D5. At this time, the Zener diodes D4 and D5 are working, the line current is 1mA, and the cathode voltage of the Zener diode D4 is about 11.0V, so the voltage difference between the two ends of the coil side of the relay K1 is 0.3V, which is less than the action voltage. At this time, the contacts of the relay K1 remain in a normally closed state.

[0033] When the drive signal SW changes from a low level to a high level, since the Zener diodes D4 and D5 respond very quickly, the voltage across the coil side of the relay K1 is quickly clamped to a low voltage of about 0.3V, so that the induced current on the coil side of the relay K1 is quickly released, the contacts of the relay K1 return to the normally closed state, and the output circuit is connected.

[0034] When the driving signal SW is at a low level (protection level), transistor Q1 is turned on, causing transistor Q2 and transistor Q3 to be turned on, and the voltage of the power supply VCC is added to the upper end of capacitor C2 through transistor Q3, diode D3 and diode D2.

[0035] Diode D2 and diode D3 are Schottky diodes, which have a smaller turn-on voltage (about 0.3V), a very fast speed and a lower switching capacitance, so that the line turns on faster.

[0036] The voltage of capacitor C2 cannot change suddenly, so the voltage at the lower end of capacitor C2 is also the voltage at the upper end of the coil side of relay K1, which reaches twice the voltage of VCC. The unidirectional characteristic of diode D1 prevents the double voltage from flowing to VCC.

[0037] When the lower end voltage of capacitor C2, that is, the upper end voltage of relay K1 coil side, reaches twice the VCC voltage, the lower end of relay K1 coil side is grounded through the turned-on transistor Q2. Since the capacitor voltage cannot change suddenly, the voltage difference between the upper and lower ends of relay K1 coil side is twice the VCC voltage, and the contacts of relay K1 can be quickly disconnected to protect the output circuit.

[0038] Resistors R6, R5 and diode D1 are used to quickly consume the induced current on the coil side of relay K1. Zener diodes D4 and D5 are used to clamp the lower end of the coil side of relay K1 to protect the collector of transistor Q3, so as to quickly release the voltage on the coil side of relay K1 and quickly close the contact side of relay K1, thereby ensuring circuit safety and the reliability of the relay.

[0039] Transistor Q3, diode D3, diode D2 and diode D1 are used to add 2 times VCC voltage to both ends of the coil side of relay K1, so as to quickly disconnect the contact side of relay K1 and protect the output circuit.

[0040] Zener diodes D4 and D5 are used to quickly conduct the relay coil current to the ground, thereby achieving rapid release of the relay.

[0041] The resistance value of resistor R1 is 7K ohms, the resistance value of resistor R2 is 11K ohms, the resistance value of resistor R3 is 11K ohms, the resistance value of resistor R4 is 7K ohms, the resistance value of resistor R5 is 1.5K ohms, the resistance value of resistor R6 is 700 ohms, the resistance value of resistor R7 is 90 ohms, and the resistance value of resistor R8 is 1K ohm.

[0042] The resistor R8 is a simulated load on the contact side of the relay K1, and the contact side of the relay is a high-voltage DC circuit.

[0043] Embodiment 2:

[0044] like Figure 2 As shown, a driving circuit for a bootstrap double voltage relay to quickly pull in and release, the circuit structure is as follows:

[0045] One end of the resistor R7 is grounded, and the other end is connected to the cathode of the diode D2. The cathode of the diode D3 is connected to the anode of the diode D2. The anode of the diode D3 is connected to the collector of the transistor Q3. The emitter of the transistor Q3 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the upper end of the coil side of the relay K1. One end of the capacitor C2 is connected between the resistor R7 and the diode D2, and the other end is connected to the upper end of the coil side of the relay K1. One end of the resistor R1 is connected to the power supply VCC. One end of the resistor R6 is connected to the power supply VCC. The other end of the resistor R6 is connected to the resistor R5. The other end of the resistor R5 is connected to the collector of the transistor Q2. The base of the transistor Q3 is connected between the resistor R5 and the resistor R6. The anode of the diode D1, the emitter of the transistor Q3, and the emitter of the transistor Q1 are connected to the power supply VCC. One end of the resistor R2 is connected to the drive signal SW, and one end is connected to The base of transistor Q1 and the other end of the driving signal SW are connected to the anode of Zener diode D5, the other end of resistor R1 is connected between the base of transistor Q1 and resistor R2, resistor R3 is connected between the collector of transistor Q1 and resistor R4, the base of transistor Q2 is connected to resistor R4 and one end of capacitor C1, the emitter of transistor Q2 is connected to resistor R4 and the other end of capacitor C1, the anode of Zener diode D5 is connected to the emitter of transistor Q2, capacitor C1 is connected to a grounding mechanism, the anode of Zener diode D4 is connected to the cathode of Zener diode D5, the cathode of Zener diode D4 is connected to the lower end of the coil side of relay K1, the lower end of the coil side of relay K1 is connected to the collector of transistor Q2, the voltage source V2 is a simulated high-voltage power supply, one end of which is connected to the upper end of the contact side of relay K1, and the other end is grounded, one end of resistor R8 is connected to the lower end of the contact side of relay K1, and the other end is connected to the voltage source V2.

[0046] like Figure 5 As shown, this simulation diagram is a simulation waveform diagram obtained by the inventor after conducting a simulation test on the circuit structure of Example 1, wherein Figure 5 The waveform in the upper middle part is the voltage change of the simulated load resistor R8 when the output circuit of relay K1 is disconnected. The time taken is the pull-in time, which is 5.4189us. Figure 5 The waveform in the lower middle part is the voltage change of the simulated load resistor R8 when the output circuit of relay K1 is connected. The time taken is the release time, which is 7.3315us.

[0047] The resistance value of resistor R1 is 7K ohms, the resistance value of resistor R2 is 11K ohms, the resistance value of resistor R3 is 11K ohms, the resistance value of resistor R4 is 7K ohms, the resistance value of resistor R5 is 1.5K ohms, the resistance value of resistor R6 is 700 ohms, the resistance value of resistor R7 is 90 ohms, and the resistance value of resistor R8 is 1K ohm.

[0048] The capacity of capacitor C1 is 100nF, the capacity of capacitor C2 is 50uF, the model of diode D1 is 1N5831, the model of diode D4 is 1N5830, the model of diode D3 is 1N5831, the model of Zener diode D4 is 1N754A, the model of Zener diode D5 is 1N754A, the model of transistor Q1 is 2N3906, the model of transistor Q2 is 2N3904, the model of transistor Q3 is 2N3906, and the model of relay K1 is EMR021B24.

[0049] like Figure 3 As shown, Figure 3 The circuit structure diagram of the prior art 1 is a conventional relay circuit. The input circuit of the prior art 1 includes a bias resistor R11, a filter capacitor C11, a transistor Q11, a pulse voltage source V11, a freewheeling diode D11, and a relay K11. The output circuit includes a DC voltage source V12 and a simulated load resistor R18. The pulse voltage source V11 provides a drive signal for the transistor Q11, the freewheeling diode D11 provides a release path for the induced current, and the DC voltage source V12 supplies power to the simulated load resistor R18. The inventor conducted a simulation experiment on this circuit, and the simulation results are shown in FIG. Figure 6 As shown, Figure 6 The waveform in the upper part of the figure is the voltage change of the simulated load resistor R18 when the output circuit of relay K11 is disconnected. The time used is the pull-in time, which is 15.5738us. Figure 6 The waveform in the lower part of the figure is the voltage change of the simulated load resistor R18 when the output circuit of relay K11 is connected. The time taken is the release time, which is 18.4426us.

[0050] like Figure 4 As shown, this figure is another relay circuit in the prior art, named as prior art 2. The input circuit of this circuit structure includes bias resistors R21 and R22, current limiting resistors R23 and R24, filter capacitors C21 and C22, transistors Q21 and Q22, pulse voltage source V21, voltage regulator tubes D21 and D22, and relay K21. The output circuit includes a DC voltage source V22 and a simulated load resistor R28. The pulse voltage source V21 provides a driving signal for the transistor Q21. When the coil of the relay K21 is powered off, the voltage regulator tubes D21 and D22 are forcibly clamped to quickly release the energy of the coil and protect the collector of Q22 from breakdown. The DC voltage source V22 supplies power to the simulated load resistor R28. The inventor conducted a simulation experiment on the circuit of prior art 2, and the simulation results are shown as follows. Figure 7 As shown, Figure 7 The waveform in the upper middle part is the voltage change of the simulated load resistor R28 when the output circuit of relay K21 is disconnected. The time taken is the pull-in time, which is 9.9723us. Figure 7The waveform in the lower middle part is the voltage change of the simulated load resistor R28 when the output circuit of relay K21 is connected. The time taken is the release time, which is 13.2964us.

[0051] Through the above simulation results analysis, it is obvious that the present invention has made great progress compared with the prior art 1 and the prior art 2. The pull-in time of the relay of the present invention is 5.4189us, which is almost twice as fast as the 9.9723us-15.5738us of the prior art. The release time of the relay of the present invention is 7.3315us, which is almost twice as fast as the 13.2964us-18.4426us of the prior art. At the same time, the induced current of the relay coil is also completely consumed, protecting the circuit. Therefore, the present invention realizes the rapid release of the voltage on the coil side of the relay K1 and the rapid pull-in of the contact side of the relay K1, ensuring the circuit safety and the reliability of the relay.

Claims

1. A driving circuit for fast closing and releasing of a bootstrap double voltage relay, characterized in that: One end of the resistor R7 is grounded, and the other end is connected to the cathode of the diode D2. The cathode of the diode D3 is connected to the anode of the diode D2. The anode of the diode D3 is connected to the collector of the transistor Q3. The emitter of the transistor Q3 is connected to the anode of the diode D1. The cathode of the diode D1 is connected to the upper end of the coil side of the relay K1. One end of the capacitor C2 is connected between the resistor R7 and the diode D2, and the other end is connected to the upper end of the coil side of the relay K1. One end of the resistor R1 is connected to the power supply VCC. One end of the resistor R6 is connected to the power supply VCC. The other end of the resistor R6 is connected to the resistor R5. The other end of the resistor R5 is connected to the collector of the transistor Q2. The base of the transistor Q3 is connected between the resistor R5 and the resistor R6. The anode of the diode D1 and the emitter of the transistor Q3 are connected. , the emitter of transistor Q1 is connected to the power supply VCC, one end of resistor R2 is connected to the driving signal SW, and the other end is connected to the base of transistor Q1, the other end of resistor R1 is connected between the base of transistor Q1 and resistor R2, resistor R3 is connected between the collector of transistor Q1 and resistor R4, the base of transistor Q2 is connected to resistor R4 and one end of capacitor C1, the emitter of transistor Q2 is connected to the other end of resistor R4 and capacitor C1, the anode of Zener diode D5 is connected to the emitter of transistor Q2, the anode of Zener diode D5 and the emitter of transistor Q2 are grounded, the anode of Zener diode D4 is connected to the cathode of Zener diode D5, the cathode of Zener diode D4 is connected to the lower end of the coil side of relay K1, and the lower end of the coil side of relay K1 is connected to the collector of transistor Q2.

2. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 1, characterized in that: When the drive signal SW is at a high level, transistors Q1, Q2, and Q3 are disconnected, and diode D1 is forward-conducted. At this time, the power supply VCC charges capacitor C2 through diode D1; relay K1 is in a non-working state, and the contact side remains normally closed.

3. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 1, characterized in that: When the drive signal SW changes from a low level to a high level, the induced current on the coil side of the relay K1 is released quickly, causing the contact side to return to a normally closed state, and the output circuit is connected.

4. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 1, characterized in that: When the driving signal SW is at a low level, the transistor Q1 is turned on, causing the transistor Q2 to be turned on and the transistor Q3 to be turned on. The voltage of the power supply VCC is added to the upper end of the capacitor C2 through the transistor Q3, the diode D3 and the diode D2.

5. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 4, characterized in that: The diode D2 and the diode D3 are Schottky diodes.

6. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 5, characterized in that: The voltage of capacitor C2 cannot change suddenly, so the voltage at the lower end of capacitor C2 is also the voltage at the upper end of the coil side of relay K1, which reaches twice the voltage of VCC. The unidirectional characteristic of diode D1 prevents the voltage twice VCC from flowing to VCC.

7. A driving circuit for fast closing and releasing of a bootstrap double voltage relay according to claim 6, characterized in that: When the lower end voltage of capacitor C2 and the upper end voltage of relay K1 coil side reach twice VCC voltage, the lower end of relay K1 coil side is grounded through the turned-on transistor Q2. Since the capacitor voltage cannot change suddenly, the voltage difference between the upper and lower ends of relay K1 coil side is twice VCC voltage, and the contacts of relay K1 can quickly close and open.

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