A large signal output avoids high-power isolation power output self-locking protection circuit

Abstract

The utility model provides a kind of large signal output's evading high-power isolated power output self-locking protection circuit, comprising: signal adjusting module is used to receive and adjust external ac signal to ac small signal.Signal amplification module is used to carry out power amplification after the ac small signal and obtains ac signal conversion module, for the ac signal is converted into large signal current output.By signal adjusting module, external signal is adjusted as ac small signal, and after multistage amplification and isolation conversion, output stable large current, can effectively inhibit the transient current impact generated by equipment start or working condition switching, avoid the equipment downtime caused by protection circuit malfunction.In the premise of maintaining the effectiveness of original protection mechanism, by optimizing signal processing path ensures the stability of high-power output, it is applicable to the industrial equipment power supply scene existing periodic load variation.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit technology, and in particular to a self-locking protection circuit for large signal output to avoid high-power isolated power supply output. Background Technology

[0002] While the built-in protection mechanisms of high-power isolated power supplies are designed to prevent dangerous situations such as short circuits, overcurrents, and overvoltages, ensuring equipment safety, in practical applications, these mechanisms can sometimes cause equipment to malfunction. This is because their protection logic is relatively simple; once the output voltage or current is detected to exceed a preset threshold at a certain moment, it will immediately activate self-locking protection and cut off the output.

[0003] However, such momentary over-limit fluctuations do not always represent a true malfunction. For example, during startup or in certain operating modes, the current or voltage of some devices may briefly spike to a level slightly above the normal operating range but still within the device's tolerance. In this case, the protection mechanism may mistakenly identify it as an anomaly, thus causing a misjudgment and interrupting the normal operation of the device, even if these brief fluctuations do not cause any substantial damage to the device itself. Utility Model Content

[0004] This invention provides a self-locking protection circuit for high-power isolated power supply output that avoids large signal output, suppresses instantaneous current surges caused by equipment startup or operating condition switching, and prevents equipment shutdown due to malfunction of the self-locking protection circuit.

[0005] This utility model provides a self-locking protection circuit for high-power isolated power supply output to avoid large signal output, including:

[0006] The signal conditioning module is used to receive and adjust external AC signals to a small AC signal.

[0007] A signal amplification module is used to amplify the small AC signal to obtain an AC signal;

[0008] The signal conversion module is used to convert the AC signal into a large signal current output.

[0009] Furthermore, the voltage of the AC small signal is 0V-5V.

[0010] Furthermore, the signal conditioning module includes: a first transformer and an adjustable resistor;

[0011] The first input terminal of the primary winding of the first transformer is connected to an external AC signal, and the second input terminal is grounded;

[0012] The first output terminal of the secondary winding of the first transformer is connected to the AC power supply, and the AC power supply is connected to the adjustable resistor; the first transformer outputs the AC small signal through the adjustable resistor.

[0013] Furthermore, the first gain amplification module includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, and a second capacitor;

[0014] The non-inverting input terminal of the first operational amplifier is connected to the AC small signal through a first resistor and grounded through a second resistor;

[0015] The inverting input terminal of the first operational amplifier is grounded through a third resistor and connected to the output terminal of the first operational amplifier through a fourth resistor;

[0016] The positive voltage input terminal of the first operational amplifier is grounded through the first capacitor and connected to the first power supply voltage;

[0017] The first negative voltage input terminal of the first operational amplifier is grounded through the second capacitor and connected to the second power supply voltage;

[0018] The second negative voltage input terminal of the first operational amplifier is connected to the first output terminal of the first operational amplifier through a fifth resistor;

[0019] The second output terminal of the first operational amplifier is connected to the input terminal of the second gain amplifier module through a sixth resistor;

[0020] The third output terminal of the first operational amplifier is grounded through the seventh resistor and connected to the input terminal of the second gain amplifier module through the eighth resistor.

[0021] Furthermore, the signal amplification module also includes: a second operational amplifier, a first filter capacitor bank, a second filter capacitor bank, a third capacitor, a ninth resistor, a tenth resistor, and an eleventh resistor;

[0022] One end of the seventh resistor connected to the eighth resistor is connected to the non-inverting input of the second operational amplifier;

[0023] The first negative voltage input terminal and the second negative voltage input terminal of the second operational amplifier are connected to the second power supply voltage; the first negative voltage input terminal and the second negative voltage input terminal are also grounded through the first filter capacitor bank;

[0024] The first positive voltage input terminal and the second positive voltage input terminal of the second operational amplifier are connected to the first power supply voltage; the first positive voltage input terminal and the second positive voltage input terminal are also grounded through the second filter capacitor bank;

[0025] The current limiting pin of the second operational amplifier is grounded through the ninth resistor, and the third capacitor is connected in parallel across the ninth resistor;

[0026] The inverting input terminal of the second operational amplifier is connected to the first and second output terminals of the second operational amplifier through a feedback network consisting of the tenth and eleventh resistors;

[0027] The first and second output terminals output AC signals.

[0028] Furthermore, the signal conversion module includes a second transformer and a twelfth resistor;

[0029] The first input terminal of the primary winding of the second transformer is connected to the AC signal, and the first input terminal is grounded;

[0030] The first output terminal of the secondary winding of the second transformer outputs the large signal current through the twelfth resistor, and the second output terminal is grounded.

[0031] Furthermore, the magnitude of the large signal current is 0A-10A.

[0032] Compared with the prior art, the present invention has at least the following technical effects:

[0033] The external signal is converted into a small AC signal by a signal conditioning module. After multi-stage amplification and isolation transformation, a stable large current is output, which can effectively suppress the instantaneous current surge caused by equipment startup or operating condition switching, and avoid equipment shutdown due to malfunction of the protection circuit. While maintaining the effectiveness of the original protection mechanism, the stability of high-power output is ensured by optimizing the signal processing path, making it particularly suitable for power supply scenarios of industrial equipment with periodic load changes. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the self-locking protection circuit for avoiding high-power isolated power supply output in Embodiment 1 of this utility model;

[0035] Figure 2 This is a simplified structural diagram of the signal conditioning module in Embodiment 1 of this utility model;

[0036] Figure 3 This is a simplified structural diagram of the signal amplification module in Embodiment 1 of this utility model;

[0037] Figure 4 This is a simplified structural diagram of the signal conversion module in Embodiment 1 of this utility model; Detailed Implementation

[0038] The following description, with reference to schematic diagrams, illustrates a self-locking protection circuit for large-signal output to avoid high-power isolated power supply output according to the present invention. Preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the present invention.

[0039] The present invention will be described more specifically by way of example with reference to the accompanying drawings in the following paragraphs. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0040] Please refer to Figures 1-4 This embodiment provides a self-locking protection circuit for large signal output to avoid high-power isolated power supply output, including:

[0041] The signal conditioning module is used to receive and adjust external AC signals to AC small signals.

[0042] The signal amplification module is used to amplify the AC small signal to obtain an AC signal.

[0043] The signal conversion module is used to convert the AC signal into a large signal current output.

[0044] In this embodiment, the external signal is converted into a small AC signal by a signal conditioning module. After multi-stage amplification and isolation transformation, a stable large current is output, which can effectively suppress the instantaneous current surge caused by equipment startup or operating condition switching, and avoid equipment shutdown due to malfunction of the protection circuit. While maintaining the effectiveness of the original protection mechanism, the stability of high-power output is ensured by optimizing the signal processing path, making it suitable for power supply scenarios of industrial equipment with periodic load changes.

[0045] Please refer to Figure 2 In one specific embodiment, the signal conditioning module includes: a first transformer T1 and an adjustable resistor R13.

[0046] Specifically, the first input terminal of the primary winding of the first transformer T1 is connected to an external AC signal AC_220V, and the second input terminal is grounded. The first output terminal of the secondary winding of the first transformer T1 is connected to the AC power supply AC_5V, which is connected to the adjustable resistor R13. The first transformer T1 outputs the AC small signal AC_OUT through the adjustable resistor R13.

[0047] Specifically, the external AC signal is input through the primary winding of the first transformer T1, and a stepped-down AC signal is generated in the secondary winding through electromagnetic induction. The signal output from the secondary winding is transmitted to the adjustable resistor R13. By slowly adjusting the resistance value of the adjustable resistor R13, the amplitude of the small AC signal AC_OUT output from the secondary winding can be controlled within a specific range. This ensures that the signal amplitude input to the signal amplification module is always within a safe threshold. Even if there are instantaneous fluctuations in the external power supply, the signal amplitude can be suppressed by adjusting the resistance value of the adjustable resistor R13 in real time, thereby avoiding the triggering of the self-locking protection due to instantaneous over-limit and effectively preventing false triggering of the power supply protection circuit.

[0048] Preferably, the voltage of the AC small signal AC_OUT is 0V-5V.

[0049] In one specific embodiment, a thirteenth resistor R14 is also included. One end of the thirteenth resistor R14 is connected to the center tap of the primary coil of the first transformer T1, and the other end is connected to the test point PAD_1 and ground. The test point PAD_1 is used to measure the voltage at the lower end of the thirteenth resistor R14.

[0050] In this embodiment, the signal amplification module includes a first gain amplification module and a second gain amplification module.

[0051] Specifically, the first gain amplification module is used to perform primary amplification of the AC small signal AC_OUT. The second gain amplification module is used to perform secondary amplification of the AC small signal AC_OUT after primary amplification.

[0052] In another specific embodiment, the first gain amplification module includes: a first operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a first capacitor C1, and a second capacitor C2.

[0053] The inverting input terminal of the first operational amplifier U1 is grounded through the third resistor R3 and connected to the output terminal of the first operational amplifier U1 through the fourth resistor R4.

[0054] The positive voltage input terminal of the first operational amplifier U1 is grounded through the first capacitor C1 and connected to the first power supply voltage. The first negative voltage input terminal of the first operational amplifier U1 is grounded through the second capacitor C2 and connected to the second power supply voltage. The second negative voltage input terminal of the first operational amplifier U1 is connected to the first output terminal of the first operational amplifier U1 through the fifth resistor R5. The second output terminal of the first operational amplifier U1 is connected to the input terminal of the second gain amplifier module through the sixth resistor R6. The third output terminal of the first operational amplifier U1 is grounded through the seventh resistor R7 and connected to the input terminal of the second gain amplifier module through the eighth resistor R8.

[0055] In the above specific embodiment, when the small AC signal AC_OUT is input to the non-inverting input terminal of the first operational amplifier U1, the amplitude of the input signal can be adjusted by the voltage division effect of the first resistor R1 and the second resistor R2. For example, the input signal of 0-5V can be attenuated to a voltage range suitable for the processing of the amplifier circuit. The inverting input terminal is grounded through the third resistor R3 to form a virtual ground. The ratio of the fourth resistor R4 to the third resistor R3 in the feedback network determines the primary amplification factor. For example, when the resistance of the fourth resistor R4 is 5 times the resistance of the third resistor R3, a voltage gain of 5 times can be achieved. The positive and negative power supply terminals are respectively connected to a filtered and stable DC voltage. The first capacitor C1 and the second capacitor C2 can effectively absorb the ripple interference on the power supply line, so that the first operational amplifier U1 maintains a stable operating point during the amplification process. The amplified signal is fed back to the inverting input terminal through the fifth resistor R5 to form a closed-loop control. At the same time, the sixth resistor R6 and the eighth resistor R8 form a voltage divider output, coupling the primary amplified signal to the secondary amplifier circuit for further processing.

[0056] In the above specific embodiment, the first operational amplifier U1 can be implemented using an OPA549 operational amplifier, forming an inverting amplifier circuit structure by configuring an external resistor network. The first resistor R1 is 0Ω, equivalent to a wire. The third resistor R3 and the fourth resistor R4 form a feedback network, which can be implemented using a resistor combination with a resistance ratio of 1:10, used to set the gain parameters of the primary amplifier circuit. The first capacitor and the second capacitor are decoupling capacitors, which can be implemented using ceramic capacitors with a capacitance of 0.1μF-10μF, used to filter out high-frequency and low-frequency noise interference in the power supply voltage.

[0057] In another specific embodiment, the signal amplification module further includes: a second operational amplifier U2, a first filter capacitor bank, a second filter capacitor bank, a third capacitor C3, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11.

[0058] One end of the seventh resistor R7 and the eighth resistor R8 is connected to the non-inverting input of the second operational amplifier U2. The first negative voltage input V1- and the second negative voltage input V2- of the second operational amplifier U2 are connected to the second power supply voltage -30V; the first negative voltage input V1- and the second negative voltage input V2- are also grounded through the first filter capacitor bank. The first positive voltage input V1+ and the second positive voltage input V2+ of the second operational amplifier U2 are connected to the first power supply voltage +30V. The first positive voltage input V1+ and the second positive voltage input V2+ are also grounded through the second filter capacitor bank. The current limiting pin of the second operational amplifier is grounded through the ninth resistor R9, and the third capacitor C3 is connected in parallel across the ninth resistor R9. The inverting input of the second operational amplifier U2 is connected to the first output VO1 and the second output VO2 of the second operational amplifier U2 through a feedback network composed of the tenth resistor R10 and the eleventh resistor R11. The first output VO1 and the second output VO2 output an AC signal OUT_OPA54549.

[0059] Specifically, the second operational amplifier U2 receives the signal from the preamplifier module through its non-inverting input. Its negative voltage input is connected to the power supply voltage and is filtered by a group of capacitors to eliminate power supply interference. The positive voltage input is connected to another power supply and is further stabilized by a second group of capacitors. The inverting input feeds the output signal back to the input through a feedback network, forming a closed-loop control to maintain the stability of the amplification process. Stable closed-loop gain control is achieved through the feedback network composed of the tenth resistor R10 and the eleventh resistor R11, resulting in good linearity and low distortion characteristics for the AC signal OUT_OPA54549 output from the first output VO1 and the second output VO2.

[0060] In one specific embodiment, the second operational amplifier U1 can also be implemented using an operational amplifier of model OPA549.

[0061] In another specific embodiment, please refer to Figure 3 The first and second filter capacitor groups are filter units composed of multiple capacitors connected in parallel or series, specifically electrolytic capacitors or ceramic capacitors, used to filter out high-frequency noise in the power supply voltage.

[0062] In one specific embodiment, the first filter capacitor group includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7 connected in parallel in sequence, and the second filter capacitor group includes an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, and an eleventh capacitor C11 connected in parallel in sequence. It is understood that the number of filter capacitors can be optimized according to specific application scenarios, performance requirements, and cost constraints. No specific limitations are imposed here.

[0063] In summary, in the above embodiments, the first gain amplification module receives a small AC signal AC_OUT from the signal conditioning module and amplifies the primary voltage by setting the feedback resistor ratio of the operational amplifier, for example, amplifying the input signal to an intermediate amplitude range. The amplified signal is then passed to the second gain amplification module, where it undergoes power amplification through a second-stage operational amplifier, ultimately boosting the signal to the power level required to drive the transformer. The two amplification modules are coupled between stages using RC components, with the signal amplified by the first stage input to the second stage via a resistor divider network, ensuring that the two amplification stages have matched impedance characteristics.

[0064] In one specific embodiment, the signal conversion module includes a second transformer T2 and a twelfth resistor R12. The first input terminal 1 of the primary winding of the second transformer T2 is connected to the AC signal OUT_OPA54549, the second input terminal 2 is grounded, the first output terminal 4 of the secondary winding outputs a large signal current through the twelfth resistor R12, and the second output terminal 3 is grounded.

[0065] In the above specific embodiment, the AC signal OUT_OPA54549 is input through the primary winding of the second transformer T2. Under the action of magnetic core coupling, the secondary winding induces a higher amplitude current signal. One end of the primary winding is directly grounded, and the other end is connected to the AC signal OUT_OPA54549. One end of the secondary winding outputs a large signal current OUT_OP, and the other end is grounded to form a loop. The twelfth resistor R12 is connected in series at the output terminal of the secondary winding. By limiting the maximum current of the output loop, it avoids triggering the self-locking protection mechanism due to instantaneous overcurrent. Thus, the cooperation between the second transformer T2 and the twelfth resistor R12 can ensure that the output current is stable within a preset range.

[0066] In one specific embodiment, the second transformer T2 can be implemented using a ferrite core wound with a double winding structure. The primary winding receives the amplified AC signal OUT_OPA54549, and the secondary winding boosts the current to the target range before outputting it. The twelfth resistor R12 is used to limit the output circuit current; it can be implemented using a metal film resistor or a wire-wound resistor. By adjusting the resistance value, the amplitude of the output current is controlled to prevent overcurrent from causing false triggering of the protection circuit.

[0067] In this embodiment, the final output large signal current OUT_OP can be limited to a specific range by adjusting the circuit component parameters. Specifically, this can be achieved by adjusting the matching relationship between the turns ratio of the second transformer T2 winding and the resistance value of the twelfth resistor R12. By adjusting the synergistic effect of the transformer turns ratio and the load resistance, a stable current range is formed at the output terminal. This range is set to balance the relationship between the equipment load capacity and the protection threshold, avoiding false protection triggered by instantaneous current exceeding the limit.

[0068] Please refer to Figure 4 In this embodiment, when the primary winding of the second transformer T2 receives the AC signal OUT_OPA54549, the turns ratio of the secondary winding and the twelfth resistor R12 together determine the amplitude of the output current.

[0069] In one specific embodiment, the turns ratio of the primary winding to the secondary winding of the second transformer T2 is 20:1. When the turns ratio of the primary winding to the secondary winding of the second transformer T2 is 20:1, the resistance value of the twelfth resistor R12 can be selected as a precision power resistor of 0.1Ω-1Ω. Then, the final output large signal current OUT_OP is 0A-10A.

[0070] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A self-locking protection circuit for large signal output to avoid high-power isolated power supply output, characterized in that, include: The signal conditioning module is used to receive and adjust external AC signals to a small AC signal. A signal amplification module is used to amplify the small AC signal to obtain an AC signal; The signal conversion module is used to convert the AC signal into a large signal current output.

2. The self-locking protection circuit for avoiding high-power isolated power supply output of large signal output as described in claim 1, characterized in that, The signal conditioning module includes: a first transformer and an adjustable resistor; The first input terminal of the primary winding of the first transformer is connected to an external AC signal, and the second input terminal is grounded; The first output terminal of the secondary winding of the first transformer is connected to an AC power supply, which is connected to the adjustable resistor; the first transformer outputs the small AC signal through the adjustable resistor.

3. The self-locking protection circuit for avoiding high-power isolated power supply output of large signal output as described in claim 1, characterized in that, The voltage of the AC small signal is 0V-5V.

4. The self-locking protection circuit for large signal output to avoid high-power isolated power supply output as described in claim 1, characterized in that, The signal amplification module includes a first gain amplification module and a second gain amplification module; The first gain amplification module is used to perform primary amplification on the AC small signal; The second gain amplification module is used to perform secondary amplification on the AC small signal after primary amplification.

5. The self-locking protection circuit for avoiding high-power isolated power supply output of large signal output as described in claim 4, characterized in that, The first gain amplification module includes: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, and a second capacitor; The non-inverting input terminal of the first operational amplifier is connected to the AC small signal through a first resistor and grounded through a second resistor; The inverting input terminal of the first operational amplifier is grounded through a third resistor and connected to the output terminal of the first operational amplifier through a fourth resistor; The positive voltage input terminal of the first operational amplifier is grounded through the first capacitor and connected to the first power supply voltage; The first negative voltage input terminal of the first operational amplifier is grounded through the second capacitor and connected to the second power supply voltage; The second negative voltage input terminal of the first operational amplifier is connected to the first output terminal of the first operational amplifier through a fifth resistor; The second output terminal of the first operational amplifier is connected to the input terminal of the second gain amplifier module through a sixth resistor; The third output terminal of the first operational amplifier is grounded through the seventh resistor and connected to the input terminal of the second gain amplifier module through the eighth resistor.

6. The self-locking protection circuit for avoiding high-power isolated power supply output of large signal output as described in claim 5, characterized in that, The signal amplification module further includes: a second operational amplifier, a first filter capacitor bank, a second filter capacitor bank, a third capacitor, a ninth resistor, a tenth resistor, and an eleventh resistor; One end of the seventh resistor connected to the eighth resistor is connected to the non-inverting input of the second operational amplifier; The first negative voltage input terminal and the second negative voltage input terminal of the second operational amplifier are connected to the second power supply voltage; the first negative voltage input terminal and the second negative voltage input terminal are also grounded through the first filter capacitor bank; The first positive voltage input terminal and the second positive and negative voltage input terminal of the second operational amplifier are connected to the first power supply voltage; the first positive voltage input terminal and the second positive voltage input terminal are also grounded through the second filter capacitor bank; The current limiting pin of the second operational amplifier is grounded through the ninth resistor, and the third capacitor is connected in parallel across the ninth resistor; The inverting input terminal of the second operational amplifier is connected to the first and second output terminals of the second operational amplifier through a feedback network consisting of the tenth and eleventh resistors; The first and second output terminals output AC signals.

7. The self-locking protection circuit for large signal output to avoid high-power isolated power supply output as described in claim 6, characterized in that, The signal conversion module includes a second transformer and a twelfth resistor; The first input terminal of the primary winding of the second transformer is connected to the AC signal, and the first input terminal is grounded; The first output terminal of the secondary winding of the second transformer outputs the large signal current through the twelfth resistor, and the second output terminal is grounded.

8. The self-locking protection circuit for avoiding high-power isolated power supply output of large signal output as described in claim 7, characterized in that, The magnitude of the large signal current is 5A-10A.

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