Isolated time-delay electronically controlled switch with current surge suppression

Abstract

The present invention relates to the technical field of time delay circuits, and discloses an isolated time delay electronic control switch with a current surge suppression function, comprising: a current surge suppression circuit, configured to increase the time delay of an RC delay circuit based on a voltage stabilizing diode and suppress current surges, while outputting a voltage control signal; an isolated time delay control circuit, configured to receive the voltage control signal output by the current surge suppression circuit, and generate a time delay based on a combination of a photocoupler and a transistor, to achieve a power-on sequence and switch switching. The present invention can simultaneously achieve a power-on sequence, a switch switching function, and a current surge resistance function under the condition of satisfying the time delay, and avoid mutual interference between signals to cause loop oscillation and burn out of sensitive devices.

Description

Technical Field

[0001] The invention relates to the technical field of time delay circuits, and in particular to an isolated time delay electronic control switch with a current surge suppression function. Background Art

[0002] High-frequency and high-speed circuits are becoming more and more widespread, and signals are becoming more and more complicated, and the demand for delay circuits is increasing. Most delay circuits on the market do not have isolation effects and do not have current surge resistance. Using a simple RC circuit, the delay effect is achieved by increasing the resistance and capacitance of RC. Although the circuit is simple, it lacks stability and does not have an isolation effect. Large capacitor charging and discharging current pulses can easily cause surge currents, causing the circuit to generate oscillation signals and even burn sensitive electrical appliances. Due to the limitations of RC, it is impossible to simultaneously achieve power-on sequence, switch switching function and current surge resistance under the condition of meeting the delay. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes an isolated time-delay electronic control switch with current surge suppression function, which can realize power-on sequence, switch switching function and current surge resistance function while meeting the time delay condition.

[0004] The technical solution adopted by the present invention is as follows:

[0005] An isolated time-delay electronic control switch with current surge suppression function, comprising:

[0006] A current surge suppression circuit is configured to increase the time delay of the RC delay circuit based on a voltage zener diode and suppress the current surge, while outputting a voltage control signal;

[0007] The isolated delay control circuit is configured to receive the voltage control signal output by the current surge suppression circuit, and generate a delay based on the combination of a photocoupler and a transistor to achieve a power-on sequence and switch switching.

[0008] Furthermore, the isolated delay control circuit includes a front-stage delay control circuit and a rear-stage delay control circuit, and the front-stage delay control circuit is connected to the rear-stage delay control circuit via a photoelectric coupler.

[0009] Furthermore, the front-stage delay control circuit includes a first resistor, a second resistor and a first capacitor, the first end of the first resistor is connected to the voltage control signal output by the current surge suppression circuit, and the second end is connected to the second resistor, the first capacitor and the first end of the photoelectric coupler, and the second ends of the second resistor, the first capacitor and the photoelectric coupler are respectively connected to the voltage ground signal.

[0010] Furthermore, the post-stage delay control circuit includes a first voltage zener diode, a first transistor, a third resistor, a fourth resistor and a second capacitor. The third end of the photoelectric coupler is respectively connected to the positive electrode of the first voltage zener diode, the second end of the fourth resistor, the second end of the second capacitor and the source of the first transistor. The fourth end of the photoelectric coupler is respectively connected to the negative electrode of the first voltage zener diode, the second end of the third resistor, the first end of the fourth resistor, the first end of the second capacitor and the gate of the first transistor. The first end of the third resistor is connected to the external input voltage, and the drain of the first transistor outputs a controlled voltage.

[0011] Furthermore, the current surge suppression circuit includes an improved RC delay circuit, which includes a second transistor, a second voltage zener diode, a third voltage zener diode, a fifth resistor, a sixth resistor, a seventh resistor and a third capacitor; the first end of the fifth resistor is connected to the voltage control signal, and the second end is respectively connected to the cathode of the second voltage zener diode, the cathode of the third voltage zener diode, the first end of the third capacitor and the first end of the sixth resistor; the second end of the third capacitor, the second end of the sixth resistor, the anode of the third voltage zener diode and the source of the second transistor are respectively connected to the voltage ground signal input end; the anode of the second voltage zener diode is connected to the gate of the second transistor through the seventh resistor, and the drain of the second transistor is connected to the voltage ground signal.

[0012] Furthermore, in the improved RC delay circuit, the second voltage regulator diode is configured to increase the charging time of the third capacitor, so that the second transistor is turned on more slowly.

[0013] Furthermore, in the improved RC delay circuit, the voltage control signal charges the third capacitor through the fifth resistor, and limits the current of the gate of the second transistor through the seventh resistor.

[0014] Furthermore, in the improved RC delay circuit, the third voltage stabilizing diode is configured to limit the voltage across the third capacitor so that the gate-source voltage of the second transistor is within a preset threshold.

[0015] Furthermore, the current surge suppression circuit also includes a parallel circuit, which includes a third transistor and an eighth resistor, the gate of the third transistor is connected to the voltage control signal through the eighth resistor, the second voltage regulator diode and the fifth resistor in sequence, the source of the third transistor is connected to the voltage ground signal input terminal, and the drain is connected to the voltage ground signal.

[0016] Furthermore, in the parallel circuit, the third transistor works in cooperation with the second transistor and shunts the second voltage regulator diode.

[0017] The beneficial effects of the present invention are:

[0018] The present invention proposes an isolated time-delay electronic control switch with current surge suppression function, which can realize input and output isolation, and the control voltage and the controlled voltage are isolated from each other without interfering with each other; the power-on timing sequence and multi-channel control can be realized together, the delay is controllable, and it has surge current protection; it has little impact on the front stage of the circuit, strong reproducibility, and low cost. The present invention can realize the power-on sequence, switch switching function and current surge resistance function at the same time under the condition of meeting the time delay, and avoid mutual interference between signals to cause loop oscillation and burn sensitive devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a simple RC delay circuit schematic.

[0020] Figure 2 It is a schematic diagram of an improved RC delay circuit according to an embodiment of the present invention.

[0021] Figure 3 It is a schematic diagram of a current surge suppression circuit according to an embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of an isolated delay control circuit according to an embodiment of the present invention.

[0023] Figure 5 The invention discloses an isolated time-delay electronic control switch with current surge suppression function. DETAILED DESCRIPTION

[0024] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only 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 those skilled in the art without making creative work are within the scope of protection of the present invention.

[0025] This embodiment provides an isolated time-delay electronic control switch with a current surge suppression function, including a current surge suppression circuit and an isolated time-delay control circuit. The current surge suppression circuit is configured to increase the time delay of the RC delay circuit based on a voltage-stabilizing diode and suppress the current surge, while outputting a voltage control signal V_c; the isolated time-delay control circuit is configured to receive the voltage control signal V_c output by the current surge suppression circuit, and generate a time delay based on a combination of an optocoupler OP1 and a transistor, so as to realize a power-on sequence and switch switching.

[0026] like Figure 1The figure shows a simple RC delay circuit, whose charging time constant τ=C3*(R5 / / R6), the voltage control signal V_c charges the third capacitor C3 through the fifth resistor R5, and limits the current of the gate of the second transistor V3 through the seventh resistor R7. The third voltage stabilizing diode V6 is used to limit the voltage across the third capacitor C3 to prevent the gate-source voltage V_gs of the second transistor V3 from being too large and being damaged due to excessive voltage, and the second transistor V3 is turned on smoothly through the charging time constant τ to achieve a delay effect.

[0027] Preferably, this embodiment proposes an improved RC delay circuit, which is applied to a current surge suppression circuit. Figure 2 As shown, the improved RC delay circuit includes a second transistor V3, a second voltage zener diode V5, a third voltage zener diode V6, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a third capacitor C3; the first end of the fifth resistor R5 is connected to the voltage control signal V_c, and the second end is respectively connected to the cathode of the second voltage zener diode V5, the cathode of the third voltage zener diode V6, the first end of the third capacitor C3 and the first end of the sixth resistor R6; the second end of the third capacitor C3, the second end of the sixth resistor R6, the anode of the third voltage zener diode V6 and the source of the second transistor V3 are respectively connected to the voltage ground signal input terminal V_c_GND_In; the anode of the second voltage zener diode V5 is connected to the gate of the second transistor V3 through the seventh resistor R7, and the drain of the second transistor V3 is connected to the voltage ground signal V_c_GND.

[0028] It should be noted that in the improved RC delay circuit of the current surge suppression circuit of this embodiment, the second voltage stabilizing diode V5 increases the charging time of the third capacitor C3, so that the second transistor V3 is turned on more slowly. This replaces the increase in the resistance and capacitance of the capacitor or resistor, on the one hand, to avoid the gate voltage of the second transistor V3 being too small, resulting in the second transistor V3 being unable to turn on normally; on the other hand, to avoid the voltage change being too large due to the excessive capacitance, resulting in a peak current.

[0029] More preferably, if Figure 3 As shown, the current surge suppression circuit of this embodiment also includes a parallel circuit, which includes a third transistor V4 and an eighth resistor R8, the gate of the third transistor V4 is connected to the voltage control signal V_c through the eighth resistor R8, the second voltage zener diode V5 and the fifth resistor R5 in sequence, the source of the third transistor V4 is connected to the voltage ground signal input terminal V_c_GND_In, and the drain is connected to the voltage ground signal V_c_GND.

[0030] It should be noted that in the parallel circuit of the current surge suppression circuit of this embodiment, the third transistor V4 is connected in parallel with the second transistor V3. On the one hand, the third transistor V4 works in conjunction with the second transistor V3 to prevent the transistor from being damaged and unable to work due to accidental circumstances; on the other hand, the second voltage regulator diode V5 is shunted to prevent the second voltage regulator diode V5 from being damaged by excessive current during instantaneous charging and discharging of the capacitor.

[0031] Preferably, the isolated delay control circuit of this embodiment includes a front-stage delay control circuit and a rear-stage delay control circuit, and the front-stage delay control circuit is connected to the rear-stage delay control circuit via a photocoupler OP1.

[0032] More preferably, if Figure 4 As shown, the front-stage delay control circuit includes a first resistor R1, a second resistor R2 and a first capacitor C1, the first end of the first resistor R1 is connected to the voltage control signal V_c output by the current surge suppression circuit, and the second end is connected to the second resistor R2, the first capacitor C1 and the first end of the photocoupler OP1, and the second end of the second resistor R2, the first capacitor C1 and the photocoupler OP1 is respectively connected to the voltage ground signal V_c_GND. The rear-stage delay control circuit includes a first voltage zener diode V1, a first transistor V2, a third resistor R3, a fourth resistor R4 and a second capacitor C2, the third end of the photocoupler OP1 is respectively connected to the positive electrode of the first voltage zener diode V1, the second end of the fourth resistor R4, the second end of the second capacitor C2 and the source of the first transistor V2, the fourth end of the photocoupler OP1 is respectively connected to the negative electrode of the first voltage zener diode V1, the second end of the third resistor R3, the first end of the fourth resistor R4, the first end of the second capacitor C2 and the gate of the first transistor V2, the first end of the third resistor R3 is connected to the external input voltage VDD, and the drain of the first transistor V2 outputs the controlled voltage V_a.

[0033] like Figure 4 As shown, in the isolated delay control circuit of this embodiment:

[0034] The voltage control signal V_c is limited by the first resistor R1 and the second resistor R2 to supply power to the photodiode in the photocoupler OP1. Figure 4is the electrical signal from pin 1 to pin 2 of the optocoupler OP1. When the photodiode in the optocoupler OP1 emits light due to the electrical signal, it stimulates the photo-controlled transistor in the optocoupler OP1 to produce a photoelectric effect to conduct the channel, so that pin 4 and pin 3 are short-circuited. At this time, the first voltage-stabilizing diode V1, the fourth resistor R4, and the second capacitor C2 in the circuit are all short-circuited to VDD_GND due to the conduction of pins 3 and 4 of the optocoupler OP1. For the first transistor V2, the voltages of both the gate and the source V_G-V_S=VDD_GND-VDD_GND=0, so the drain voltage V_D of the first transistor V2=controlled voltage V_a, which can be regarded as the switch being turned on. In the above analysis, the second capacitor C2 and the fourth resistor R4 are both short-circuited, so the delay at this time is not generated by RC, but by the combination of the optocoupler OP1 and the first transistor V2, which can quickly realize the power-on sequence and achieve a millisecond delay effect.

[0035] When the voltage control signal V_c is no longer provided, no current flows through pins 1 and 2 of the input end of the optocoupler OP1, the photodiode turns off, causing pins 3 and 4 of the output end of the optocoupler OP1 to be disconnected, and the first voltage regulator diode V1 clamps the voltage to protect the output end of the optocoupler OP1 from being burned. The resistors R3 and R4 divide the voltage to provide voltage for the gate of the first transistor V2, and R3 and C2 form a charging circuit, which can delay the power supply to the gate of the first transistor V2. When the gate voltage of the first transistor V2 is powered, a voltage drop is formed with the source, the channel is turned on, and the drain voltage V_D is equal to the source voltage V_S, so the drain voltage V_D is pulled from the controlled voltage V_a (high level) to the source voltage V_S VDD_GND (low level), thereby realizing the controllable shutdown delay.

[0036] Preferably, if Figure 5 FIG. 1 is a schematic diagram of an isolated time-delay electronic control switch with current surge suppression function according to the present embodiment, which includes: Figure 3 The current surge suppression circuit shown and Figure 4 The isolated delay control circuit shown.

[0037] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. An isolated time-delay electronic control switch with current surge suppression function, characterized in that: include: A current surge suppression circuit is configured to increase the time delay of the RC delay circuit based on a voltage zener diode and suppress the current surge, while outputting a voltage control signal (V_c); The isolated delay control circuit is configured to receive the voltage control signal (V_c) output by the current surge suppression circuit, and to generate a delay based on a combination of a photocoupler (OP1) and a transistor to achieve a power-on sequence and switch switching.

2. The isolated time-delay electronic control switch with current surge suppression function according to claim 1, characterized in that: The isolated delay control circuit comprises a front-stage delay control circuit and a rear-stage delay control circuit, wherein the front-stage delay control circuit is connected to the rear-stage delay control circuit via a photoelectric coupler (OP1).

3. The isolated time-delay electronic control switch with current surge suppression function according to claim 2, characterized in that: The front-stage delay control circuit comprises a first resistor (R1), a second resistor (R2) and a first capacitor (C1); a first end of the first resistor (R1) is connected to a voltage control signal (V_c) output by a current surge suppression circuit, and a second end is connected to the second resistor (R2), the first capacitor (C1) and a first end of a photoelectric coupler (OP1); second ends of the second resistor (R2), the first capacitor (C1) and the photoelectric coupler (OP1) are respectively connected to a voltage ground signal (V_c_GND).

4. The isolated time-delay electronic control switch with current surge suppression function according to claim 3, characterized in that: The post-stage delay control circuit comprises a first voltage stabilizing diode (V1), a first transistor (V2), a third resistor (R3), a fourth resistor (R4) and a second capacitor (C2); the third end of the photoelectric coupler (OP1) is respectively connected to the positive electrode of the first voltage stabilizing diode (V1), the second end of the fourth resistor (R4), the second end of the second capacitor (C2) and the source electrode of the first transistor (V2); the fourth end of the photoelectric coupler (OP1) is respectively connected to the negative electrode of the first voltage stabilizing diode (V1), the second end of the third resistor (R3), the first end of the fourth resistor (R4), the first end of the second capacitor (C2) and the gate electrode of the first transistor (V2); the first end of the third resistor (R3) is connected to an external input voltage (VDD); and the drain electrode of the first transistor (V2) outputs a controlled voltage (V_a).

5. The isolated time-delay electronic control switch with current surge suppression function according to claim 1, characterized in that: The current surge suppression circuit comprises an improved RC delay circuit, which comprises a second transistor (V3), a second voltage zener diode (V5), a third voltage zener diode (V6), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7) and a third capacitor (C3); a first end of the fifth resistor (R5) is connected to a voltage control signal (V_c), and a second end is respectively connected to a cathode of the second voltage zener diode (V5), a cathode of the third voltage zener diode (V6), a first end of the third capacitor (C3) and a first end of the sixth resistor (R6); a second end of the third capacitor (C3), a second end of the sixth resistor (R6), an anode of the third voltage zener diode (V6) and a source of the second transistor (V3) are respectively connected to a voltage ground signal input terminal (V_c_GND_In); an anode of the second voltage zener diode (V5) is connected to a gate of the second transistor (V3) through a seventh resistor (R7), and a drain of the second transistor (V3) is connected to a voltage ground signal (V_c_GND).

6. The isolated time-delay electronic control switch with current surge suppression function according to claim 5, characterized in that: In the improved RC delay circuit, the second voltage stabilizing diode (V5) is configured to increase the charging time of the third capacitor (C3), so that the second transistor (V3) is turned on more slowly.

7. The isolated time-delay electronic control switch with current surge suppression function according to claim 5, characterized in that: In the improved RC delay circuit, the voltage control signal (V_c) charges the third capacitor (C3) through the fifth resistor (R5), and limits the current of the gate of the second transistor (V3) through the seventh resistor (R7).

8. The isolated time-delay electronic control switch with current surge suppression function according to claim 5, characterized in that: In the improved RC delay circuit, the third voltage stabilizing diode (V6) is configured to limit the voltage across the third capacitor (C3) so that the gate-source voltage (V_gs) of the second transistor (V3) is within a preset threshold.

9. The isolated time-delay electronic control switch with current surge suppression function according to claim 5, characterized in that: The current surge suppression circuit also includes a parallel circuit, which includes a third transistor (V4) and an eighth resistor (R8), wherein the gate of the third transistor (V4) is connected to a voltage control signal (V_c) via the eighth resistor (R8), a second voltage stabilizing diode (V5) and a fifth resistor (R5) in sequence, and the source of the third transistor (V4) is connected to a voltage ground signal input terminal (V_c_GND_In), and the drain is connected to a voltage ground signal (V_c_GND).

10. The isolated time-delay electronic control switch with current surge suppression function according to claim 9, characterized in that: In the parallel circuit, the third transistor (V4) works in coordination with the second transistor (V3) and shunts the second voltage-stabilizing diode (V5).

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