DC isolation circuit and power device

Abstract

The present application provides a DC isolation circuit and power device, comprising: a waveform generator circuit connected to a power supply for generating a waveform signal; a variable gain control circuit comprising a first input terminal, a second input terminal, and a third input terminal for controlling the waveform gain of the third input terminal based on a voltage comparison between the first input terminal and the second input terminal, wherein the first input terminal is used to obtain a ground voltage, the second input terminal is used to obtain a feedback voltage, and the third input terminal is connected to the output terminal of the waveform generator circuit via an amplifying and filtering circuit to obtain the waveform signal; an inverter circuit connected to the output terminal of the variable gain control circuit via a driving circuit, and comprising an isolation transformer, the isolation transformer comprising a magnetic core, a primary winding, a secondary winding, and a feedback winding, the secondary winding being used to output a voltage, the feedback winding being connected to a feedback loop after rectification, and the feedback loop being connected to the second input terminal of the variable gain control circuit. The isolation voltage is improved and the voltage and load regulation rates are reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a DC isolation circuit and a power device. Background Art

[0002] Currently, precision equipment in the semiconductor, medical, and aerospace fields requires suspended overvoltage power supply, which usually requires very high precision of the power supply.

[0003] The use of suspended overvoltage power supply technology can provide a stable and low-noise high-voltage power supply, which is crucial for precise control and image acquisition of precision equipment. Existing high-voltage DC isolation circuits use photoelectric isolation technology, which converts optical signals into electrical signals to achieve isolation between high-voltage and low-voltage circuits. However, this technology is only suitable for scenarios with low isolation voltages (approximately 3kV to 5kV) and usually requires repeated voltage and load adjustments. Summary of the Invention

[0004] Based on this, it is necessary to address the problems in the above background technology and provide a DC isolation circuit that can achieve ultra-low voltage regulation and load regulation while improving the voltage resistance and avoiding electromagnetic interference.

[0005] To achieve the above-mentioned and other related objectives, one aspect of the present application provides a DC isolation circuit, comprising:

[0006] A waveform generator circuit is connected to a power supply, and is used for generating a waveform signal;

[0007] an amplifying and filtering circuit, used for amplifying and filtering the waveform signal output by the waveform generator circuit;

[0008] A variable gain control circuit includes a first input terminal, a second input terminal, and a third input terminal. The variable gain control circuit is used to control the waveform gain of the third input terminal based on a voltage comparison between the first input terminal and the second input terminal. The first input terminal is used to obtain a ground voltage, the second input terminal is used to obtain a feedback voltage, and the third input terminal is connected to the output terminal of the waveform generator circuit via an amplifying and filtering circuit to obtain a waveform signal.

[0009] A driving circuit, used for amplifying and shaping the waveform signal output by the variable gain control circuit;

[0010] an inverter circuit connected to the output end of the variable gain control circuit via a drive circuit, the inverter circuit comprising an isolation transformer, the isolation transformer comprising a magnetic core, a primary winding, a secondary winding and a feedback winding, the secondary winding being used to output a voltage, and the feedback winding being used to output a feedback voltage;

[0011] A feedback loop, wherein the feedback winding is connected to an input end of the feedback loop after rectification, and an output end of the feedback loop is connected to a second input end of the variable gain control circuit;

[0012] The output circuit is connected to the secondary winding and is used for rectifying the waveform signal output by the secondary winding to output a floating voltage.

[0013] In one embodiment, the primary winding and the secondary winding are respectively arranged on two sides of the magnetic core, and the feedback winding is arranged outside the secondary winding.

[0014] In one embodiment, the isolation voltage of the DC isolation circuit is adjusted based on adjusting the distance between the secondary winding and the primary winding.

[0015] In one embodiment, the isolation voltage of the DC isolation circuit is adjusted based on adjusting the distance between the secondary winding and the feedback winding.

[0016] In one embodiment, the isolation voltage range of the DC isolation circuit includes 50 kV to 150 kV.

[0017] In one embodiment, the skeletons of the primary winding, the secondary winding and the feedback winding are made of tetrafluoroethylene material.

[0018] In one embodiment, the voltage processing circuit in the feedback loop includes a voltage divider circuit, an operational amplifier, a differential operation circuit, and a filter circuit arranged in sequence, which are used to perform voltage division, operational amplification, differential operation, and filtering on the feedback voltage and the power supply voltage in sequence. After being processed by the feedback loop, the feedback voltage is input into the second input terminal of the variable gain control circuit.

[0019] In one embodiment, the variable gain control circuit includes a variable gain amplifier, a first pin of the variable gain amplifier is grounded and serves as a first input terminal, a second pin of the variable gain amplifier is connected to a voltage processing circuit in a feedback loop to obtain a processed feedback voltage, a third pin of the variable gain amplifier is connected to an output terminal of an amplifying and filtering circuit, and an input terminal of the amplifying and filtering circuit is connected to an output terminal of a waveform generator circuit.

[0020] In one embodiment, the waveform of the waveform signal comprises a sine wave.

[0021] The present application also provides an electric power device, comprising any one of the above DC isolation circuits.

[0022] According to the DC isolation circuit and power device provided in the present application, an isolation transformer is provided in the inverter circuit to increase the isolation voltage, and the feedback voltage is transmitted to the variable gain control circuit through the feedback winding of the isolation transformer through the feedback loop. The waveform gain of the third input terminal is controlled based on the voltage comparison between the first input terminal and the second input terminal of the variable gain control circuit, thereby realizing closed-loop regulation of the DC isolation circuit and reducing the voltage regulation rate and load regulation rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to better describe and illustrate the embodiments and / or examples of the applications disclosed herein, reference may be made to one or more of the accompanying drawings. The additional details or examples used to describe the accompanying drawings should not be considered to limit the scope of the disclosed applications, the presently described embodiments and / or examples, and any of the best modes currently understood for these applications.

[0024] Figure 1 is a principle block diagram of a DC isolation circuit provided in one embodiment;

[0025] Figure 2 is a circuit diagram of a waveform generator circuit provided in one embodiment;

[0026] Figure 3 is a circuit diagram of a variable gain control circuit and a feedback loop provided in one embodiment;

[0027] Figure 4 is a circuit diagram of an inverter circuit provided in one embodiment;

[0028] Figure 5 Schematic diagram of the structure of an isolation transformer provided in one embodiment.

[0029] Description of reference numerals:

[0030] 10. Waveform generator circuit; 20. Amplifier and filter circuit; 30. Variable gain control circuit; 40. Drive circuit; 50. Inverter circuit; 501. Magnetic core; 502. Primary winding; 503. Secondary winding; 504. Feedback winding; 60. Feedback loop; 70. Output circuit. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present application, a more comprehensive description of the present application will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0033] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present application. When used herein, the singular forms "a", "an", and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0034] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present application in a schematic manner. Although the illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation, the type, quantity and proportion of each component in actual implementation can be changed at will, and the component layout type may also be more complicated.

[0035] This application provides a DC isolation circuit, such as Figure 1 As shown, it includes a waveform generator circuit 10, an amplifying and filtering circuit 20, a variable gain control circuit 30, a driving circuit 40, an inverter circuit 50, a feedback loop 60 and an output circuit 70. Among them:

[0036] A waveform generator circuit 10 is connected to a power supply and configured to generate a waveform signal;

[0037] an amplifying and filtering circuit 20 for amplifying and filtering the waveform signal output by the waveform generator circuit 10;

[0038] A variable gain control circuit 30 includes a first input terminal, a second input terminal, and a third input terminal. The variable gain control circuit is used to control the waveform gain of the third input terminal based on a voltage comparison between the first input terminal and the second input terminal. The first input terminal is used to obtain a ground voltage, the second input terminal is used to obtain a feedback voltage, and the third input terminal is connected to the output terminal of the waveform generator circuit 10 via the amplifying and filtering circuit 20 to obtain a waveform signal.

[0039] The driving circuit 40 is used to amplify and shape the waveform signal output by the variable gain control circuit 30;

[0040] an inverter circuit 50 connected to the output end of the variable gain control circuit 30 via the drive circuit 40 , the inverter circuit comprising an isolation transformer, the isolation transformer comprising a magnetic core, a primary winding, a secondary winding, and a feedback winding, the secondary winding being configured to output a voltage, and the feedback winding being configured to output a feedback voltage;

[0041] A feedback loop 60 , wherein the feedback winding is connected to the input end of the feedback loop 60 after rectification, and the output end of the feedback loop 60 is connected to the second input end of the variable gain control circuit 30 ;

[0042] The output circuit 70 is connected to the secondary winding and is used to rectify the waveform signal output by the secondary winding to output a floating voltage.

[0043] In one embodiment, the waveform generator circuit 10 requires only a DC power supply and can self-oscillate to generate waveform signals, such as sine waves, triangle waves, square waves, and rectangular waves, without the need for an external signal. The choice of waveform can determine whether the entire DC isolation circuit can operate in demanding applications. For example, when the waveform generated by the waveform generator circuit 10 is a square wave, the square wave drive will generate high-order harmonics. High-order harmonics can harm the power system and interfere with the communication system, such as causing voltage and current waveform distortion, reducing equipment efficiency, affecting communication quality and the normal operation of the communication system, and causing information loss. Preferably, the waveform signal generated by the waveform generator circuit 10 is a sine wave to avoid generating high-order harmonics, thereby preventing damage to the power system and communication system.

[0044] In one embodiment, Figure 2As shown, the waveform generator circuit 10 includes a waveform generator U1, an oscillation circuit, and a filter circuit. Pin 8 (VCC) of the waveform generator U1 is connected to the voltage VCC, and pin 1 (GND) of the waveform generator U1 is grounded. The oscillation circuit includes resistor R1, resistor R3, and capacitor C8 to form the chip oscillation frequency f=1.44 / (R1+2R3)×C8. Among them, the resistor R1, the resistor R3, and the capacitor C8 are connected in series in sequence. The first end of the resistor R1 is connected to the voltage VCC and pin 8 (VCC) of the waveform generator U1, the second end of the resistor R1 is connected to the first end of the resistor R3 and pin 7 (DISCH) of the waveform generator U1, the second end of the resistor R3 is connected to pin 6 (THRES) of the waveform generator U1, the second end of the resistor R3 is connected to the first end of the capacitor C8, and the second end of the capacitor C8 is grounded; pin 6 (THRES) of the waveform generator U1 is connected to pin 2 (TRIG) of the waveform generator U1; Pin 5 (CONT) of waveform generator U1 is connected to ground via capacitor C3; Pin 1 (GND) of waveform generator U1 is connected to ground; Pin 3 (OUT) of waveform generator U1 is connected to ground via resistor R7; Pin 4 (RESET) of waveform generator U1 is connected to voltage VCC via resistor R2. The first end of resistor R2 is connected to voltage VCC and the first end of capacitor C2. The second end of resistor R2 is connected to pin 4 (RESET) of waveform generator U1. The second end of capacitor C2 is grounded. Capacitors C2 and C3 act as filter capacitors, and resistor R2 acts as a pull-up resistor. The first end of capacitor C7 is connected to pin 3 (OUT) of waveform generator U1 via capacitor C1, and the second end of capacitor C7 is grounded. Capacitors C1 and C7 optimize the waveform, and resistor R7 limits the output.

[0045] Please continue to refer to Figure 2 The filter circuit includes a resistor R6, a capacitor C6, a resistor R5, a capacitor C5, a resistor R4, and a capacitor C4, to make the waveform of the emitted sine wave more standardized. The first end of capacitor C6 is connected to the first end of capacitor C7 via resistor R6, and the second end of capacitor C6 is grounded. The first end of capacitor C5 is connected to the first end of capacitor C6 via resistor R5, and the second end of capacitor C5 is grounded. The first end of capacitor C4 is connected to the first end of capacitor C5 via resistor R4, and the second end of capacitor C4 is grounded.

[0046] In one embodiment, the amplifying and filtering circuit 20 includes a waveform amplifying circuit and a filtering circuit. The input end of the amplifying and filtering circuit 20 is connected to the output end of the waveform generator circuit 10, and performs waveform amplification and filtering on the sine wave output by the waveform generator circuit 10.

[0047] In one embodiment, the variable gain control circuit 30 includes a variable gain amplifier. A first pin of the variable gain amplifier U2 is grounded and serves as the first input terminal. A second pin of the variable gain amplifier U2 is connected to the output terminal of the feedback loop 60 to obtain a processed feedback voltage. A third pin of the variable gain amplifier U2 is connected to the output terminal of the amplifying and filtering circuit 20. The input terminal of the amplifying and filtering circuit 20 is connected to the output terminal of the waveform generator circuit 10.

[0048] In one embodiment, Figure 3 As shown, variable gain amplifier U2 includes eight pins. Pin 1 (GPOS) is grounded and serves as the first input of variable gain control circuit 30 to obtain a ground voltage. Pin 2 (GNEG) serves as the second input of variable gain control circuit 30 and is connected to the feedback winding of inverter circuit 50 via feedback loop 60 to obtain a feedback voltage after rectification. Pin 3 (VINP) serves as the third input of variable gain control circuit 30 and is connected to the output of waveform generator circuit 10 via amplification and filtering circuit 20 to obtain a waveform signal. Variable gain amplifier U2 compares the ground voltage at pin 1 with the feedback voltage at pin 2 and, based on the comparison data, controls the gain of the waveform at pin 3, thereby amplifying or reducing the waveform input to pin 3. The amplified or reduced waveform is then output to the input of driver circuit 40 via pins 5 (FDBK) and 7 (VOUT) of variable gain amplifier U2.

[0049] In one embodiment, Figure 3As shown, feedback loop 60 includes a voltage divider circuit for the feedback voltage and an operational amplifier U3. Specifically, the voltage divider circuit for feedback voltage VF includes resistors R10 and R11 connected in series. The first end of resistor R10 is connected to feedback voltage VF, and the second end is connected to the first end of resistor R11. The second end of resistor R11 is grounded. The first input (the "+" input or positive input) of operational amplifier U3 is connected to the second end of resistor R10, and the second input (the "-" input or negative input) of operational amplifier U3 is connected to the output of operational amplifier U3. The output of operational amplifier U3 is connected to the positive input of differential operator U5 via resistor R14. Because the feedback voltage has a relatively weak driving capability, after being divided by the voltage divider circuit, the operational amplifier U3 follows and boosts the driving capability of the feedback voltage. Feedback loop 60 also includes a voltage divider circuit for the power supply voltage and an operational amplifier U4. Specifically, the voltage divider circuit for power supply voltage VDD includes resistors R8 and R9 connected in series. The first end of resistor R8 is connected to voltage VDD, the second end of resistor R8 is connected to the first end of resistor R9, the second end of resistor R9 is grounded, and the second end of resistor R9 is connected to the positive input of operational amplifier U4 via capacitor C9. The first input ("+" input, or positive input) of operational amplifier U4 is connected to the second end of resistor R8, and the second input ("-" input, or negative input) of operational amplifier U4 is connected to the output of operational amplifier U4. After voltage VDD is divided by the voltage divider circuit, it is followed by operational amplifier U4. Feedback loop 60 also includes a differential operation circuit, which includes a differential operator U5, resistors R12, R13, R14, and R15. The second input terminal (the "-" input terminal or the inverting input terminal) of differential operator U5 is connected to the output terminal of operational amplifier U4 via resistor R12. The second input terminal of differential operator U5 is also connected to the output terminal of differential operator U5 via resistor R13. The first input terminal (the "+" input terminal or the positive input terminal) of differential operator U5 is grounded (GND) via resistor R15. The output terminal of operational amplifier U3 is connected to the first input terminal of differential operator U5 via resistor R14. Differential operator U5 differentiates the voltages followed by operational amplifiers U4 and U3 to obtain a processed feedback voltage, making the feedback voltage more accurate. The filtering circuit includes a resistor R16 and a capacitor C10. The output end of the differential operator U5 is connected to pin 2 (GNEG) of the variable gain amplifier U2 via the resistor R16. The first end of the resistor R16 is connected to the output end of the differential operator U5, and the second end of the resistor R16 is connected to pin 2 (GNEG) of the variable gain amplifier U2. The second end of the resistor R16 is also grounded via the capacitor C10.The filter circuit is connected to the output end of the differential operator U5. The output waveform signal is RC filtered by the filter circuit and sent to pin 2 (GNEG) of the variable gain amplifier U2 after low-pass filtering.

[0050] Please continue to refer to Figure 3 In one embodiment, pin 1 (GPOS) of variable gain amplifier U2 is grounded and connected to pin 4 (COMM) of variable gain amplifier U2. Pin 3 (GPOS) of variable gain amplifier U2 is grounded via resistor R17 and is also connected to amplification and filtering circuit 20 via capacitor C11. Variable gain amplifier U2 compares the ground voltage with the feedback voltage received at pin 2 (GNEG). Based on the comparison data, the chip implements internal variable gain (amplification factor). The waveform input to pin 3 (VINP) is amplified or reduced based on the amplification factor of variable gain amplifier U2, and the waveform is output through pins 5 (FDBK) and 7 (VOUT) of variable gain amplifier U2. Specifically, the ground voltage of the first input terminal of the variable gain amplifier U2 is usually zero. When the comparison result is positive, that is, when the differential value output by the differential operator U5 is positive, the waveform is amplified; when the comparison result is negative, that is, when the differential value output by the differential operator U5 is negative, the waveform is reduced.

[0051] Please continue to refer to Figure 3 In one embodiment, pin 6 (VNEG) of the variable gain amplifier U2 is connected to voltage VEE. Pin 8 (VPOS) of the variable gain amplifier U2 is connected to voltage VDD.

[0052] Furthermore, the output of variable-gain amplifier U2 is further connected to operational amplifier U6. Specifically, pin 5 (FDBK) of variable-gain amplifier U2 is connected to pin 7 (VOUT) of variable-gain amplifier U2. Pin 7 (VOUT) of variable-gain amplifier U2 is connected to the first input (the "+" input or positive input) of operational amplifier U6 via capacitor C12 and resistor R0. The connection node of capacitor C12 and resistor R0 is connected to ground (GND) via resistor R18. The second input (the "-" input or negative input) of operational amplifier U6 is connected to the output of operational amplifier U6, and the output of operational amplifier U6 is connected to drive circuit 40. The drive waveform is output to drive circuit 40 via operational amplifier U6, thereby achieving a voltage regulation rate of ≤0.1% and a load regulation rate of ≤0.5%, and achieving balance for the entire system.

[0053] In one embodiment, the driving circuit 40 includes a waveform amplification circuit and a shaping circuit. The input end of the driving circuit 40 is connected to the output end of the variable gain control circuit 30, and the driving waveform output by the variable gain control circuit 30 is amplified and shaped.

[0054] In one embodiment, Figure 4 As shown, the inverter circuit 50 includes a switching circuit and an isolation transformer. The switching circuit includes switching transistors U7 and U8. The drive circuit 40 is connected to the control terminal of switching transistor U7 via resistor R19, and to the control terminal of switching transistor U8 via resistor R20. Switching transistors U7 and U8 are connected to the primary winding of the isolation transformer. The first terminal of switching transistor U7 is connected to the first terminal of the primary winding, the second terminal of switching transistor U7 is connected to the first terminal of switching transistor U8, and the second terminal of switching transistor U8 is connected to the fourth terminal of the primary winding. The node connecting the second and third terminals of the primary winding is connected to ground (GND) via capacitor C0. The node connecting the second and third terminals of the primary winding is also connected to voltage VCC. The node connecting voltage VCC and capacitor C0 is grounded via capacitor Cs. The drive circuit 40 switches switching transistors U7 and U8 via resistors R19 and R20, thereby generating inversion in the isolation transformer.

[0055] In one embodiment, Figure 5 As shown, the isolation transformer includes a magnetic core 501, a primary winding 502, a secondary winding 503 and a feedback winding 504. Figure 5 As shown, the primary winding 502 and the secondary winding 503 are respectively arranged on either side of the magnetic core 501. The primary winding 502 is arranged on the power supply side of the magnetic core 501 and is also referred to as the primary winding. The secondary winding 503 is arranged on the load side of the magnetic core 501 and is also referred to as the secondary winding. Furthermore, both the primary winding 502 and the secondary winding 503 are arranged outside the magnetic core 501, and the feedback winding 504 is arranged outside the secondary winding 503. By having the primary and secondary windings wound on either side of the magnetic core, the isolation voltage is increased.

[0056] Exemplarily, the isolation voltage of the DC isolation circuit can be adjusted by adjusting the distance between the secondary winding 503 and the primary winding 502. Exemplarily, the isolation voltage of the DC isolation circuit can be adjusted by adjusting the distance between the secondary winding 503 and the feedback winding 504. Specifically, the distance between the secondary winding 503 and the primary winding 502 can be adjusted by changing the distance between the two sides of the magnetic core 501, for example, by replacing the magnetic core 501 or using a magnetic core 501 with adjustable spacing on both sides. Since the feedback winding 504 is arranged outside the secondary winding 503, the distance between the secondary winding 503 and the feedback winding 504 can be adjusted by directly adjusting the position of the feedback winding 504.

[0057] In one embodiment, the magnetic core 501 adopts an isolation transformer core with excellent performance, and the primary winding 502, the secondary winding 503 and the feedback winding 504 select a special isolation transformer skeleton with good anti-electromagnetic interference performance. Specifically, the skeletons of the primary winding 502, the secondary winding 503 and the feedback winding 504 are made of tetrafluoroethylene material, which is a high-voltage resistant material. The isolation transformer is used to separate the high-voltage part and the low-voltage part, reduce the risk of electromagnetic interference and high-voltage leakage, and increase the isolation voltage. Compared with the use of optocouplers, the isolation transformer using the above structure and materials can greatly improve the isolation voltage of the DC isolation circuit. In this embodiment, the isolation voltage range of the DC isolation circuit includes 50kV~150kV, such as 50kV, 100kV, 150kV, etc.

[0058] In one embodiment, the feedback winding is connected to the second input terminal of the variable gain control circuit through the feedback loop after rectification. Figure 4As shown, the drive circuit 40 switches the switch tubes U7 and U8 through the resistors R19 and R20, thereby generating an inversion in the isolation transformer. Then, according to the turns ratio of the isolation transformer, the high-frequency voltage output by the secondary winding of the isolation transformer is full-wave rectified by the diodes D1 and D2. The anode of the diode D1 is connected to the 5th terminal of the secondary winding, the anode of the diode D2 is connected to the 8th terminal of the secondary winding, and the connection node between the 6th and 7th terminals of the secondary winding is grounded GND_ISO; the 9th terminal of the feedback winding is grounded (GND); the anode of the diode D1 is connected to the cathode of the diode D1 via the capacitor C13 and the resistor R21; the anode of the diode D2 is connected to the cathode of the diode D2 via the capacitor C14 and the resistor R22; and the cathode of the diode D2 is also connected to the cathode of the diode D1. The signal inverted by the switching tube U7, the switching tube U8, and the secondary winding of the isolation transformer is processed by the capacitor C13, the resistor R21 and / or the sub-filter circuit including the capacitor C14 and the resistor R22, and finally subjected to I-type filtering by the filter circuit composed of the capacitor C15, the capacitor C16, the inductor U9, the capacitor C17 and the capacitor C18. After the filtering is completed, a more stable output is obtained through the resistor R23. A first end of capacitor C15 is connected to the cathode of diode D1, and a second end of capacitor C15 is connected to ground GND_ISO; a first end of capacitor C16 is connected to the cathode of diode D1, and a second end of capacitor C16 is connected to ground GND_ISO; a first end of capacitor C17 is connected to the cathode of diode D1 via inductor U9, and a second end of capacitor C17 is connected to ground GND_ISO; a first end of capacitor C18 is connected to the first end of capacitor C17, and a second end of capacitor C18 is connected to ground GND_ISO; a first end of resistor R23 is connected to voltage VOUT, a second end of resistor R23 is connected to ground GND_ISO, and a first end of resistor R23 is also connected to a first end of capacitor C18.

[0059] Please continue to refer to Figure 4 The 10th terminal of the feedback winding is connected to the feedback voltage VF via diode D3, resistor R24, and resistor R25. The first terminal of resistor R24 ​​is connected to the cathode of diode D3, the second terminal of resistor R24 ​​is connected to the first terminal of resistor R25, and the second terminal of resistor R24 ​​is also connected to ground (GND) via capacitor C19. The first terminal of capacitor C20 is connected to the second terminal of resistor R24, and the second terminal of capacitor C20 is grounded (GND). The first terminal of capacitor C21 is connected to the second terminal of resistor R25, and the second terminal of capacitor C21 is grounded (GND). The first terminal of capacitor C22 is connected to the feedback voltage VF, and the second terminal of capacitor C22 is grounded (GND). The first terminal of feedback loop 60 is connected to the feedback voltage VF, and the second terminal of feedback loop 60 is connected to variable gain control circuit 30.

[0060] Please continue to refer to Figure 4In one embodiment, as Figure 4 As shown, in order to accurately capture the feedback voltage from the isolation transformer's feedback winding and ensure that the feedback voltage delivered to the second input terminal of the variable gain control circuit 30 accurately reflects changes in the output voltage "VOUT" as the load changes to adjust the system, the output current should be prevented from flowing through the feedback winding. As the output current changes, the magnetic flux of the feedback winding is captured. Since the induced electromotive force E ≈ dΦ / dt, which is opposite to the feedback terminal voltage U, it undergoes half-wave rectification via diode D3. The induced electromotive force E is filtered by resistors R24 and R25 and capacitors C19, C20, C21, and C22 before being delivered to the feedback loop 60. Based on the received feedback voltage, the feedback loop 60 determines the feedback output voltage. This feedback output voltage is then delivered to the variable gain control circuit 30 to control the output gain of the control circuit, thereby controlling the output of the drive circuit 40. This ensures that the entire DC isolation circuit operates in a closed-loop, efficient, and stable state. This achieves a voltage regulation of ≤ 0.1% and a load regulation of ≤ 0.5%.

[0061] In one embodiment, referring to Figure 1-Figure 5As shown, after the DC isolation circuit is powered on, a sine wave waveform is first emitted by the waveform generator circuit 10, which is amplified and filtered by the amplifying and filtering circuit 20 and enters the third input terminal (pin 3 of the variable gain amplifier) ​​of the variable gain control circuit 30. Based on the comparison of the ground voltage of the first input terminal (pin 1 of the variable gain amplifier) ​​and the feedback voltage of the second input terminal (pin 2 of the variable gain amplifier), the gain multiple of the third input terminal (pin 3 of the variable gain amplifier) ​​is controlled. The gained sine wave enters the driving circuit 40 for further amplification and shaping of the waveform, and then enters the inverter circuit 50 for inversion. After inversion by the isolation transformer in the inverter circuit 50, one path is used as the output voltage and is rectified by the secondary winding through the rectifier circuit for π-type rectification to output a floating voltage; the other feedback voltage is output by the feedback winding through the RC rectification to the feedback loop 60, and is first divided by the voltage divider circuit to prevent the feedback voltage from being too high, and then is operated. The operational amplifier U3 follows and improves the driving capability of the feedback voltage. The power supply voltage and the feedback voltage are then differentiated by the differential operator U5 to make the feedback voltage more accurate. The low-pass filter is then performed by the resistor R16 and the capacitor C10. The processed waveform is transmitted to the pin 2 of the variable gain amplifier U2. Based on the comparison between the ground voltage of the pin 1 of the variable gain amplifier U2 and the feedback voltage of the pin 2 of the variable gain amplifier U2, the gain multiple of the waveform input to the pin 3 of the variable gain amplifier U2 is controlled to amplify or reduce the output of the waveform. The output waveforms of pins 5 (FDBK) and 7 (VOUT) of the variable gain amplifier are processed by the capacitor C12 and the resistor R18 and then input to the input of the operational amplifier U6. The drive waveform is output to the drive circuit 40 through the operational amplifier U6, and the entire DC isolation circuit is closed-loop regulated, thereby obtaining a voltage regulation rate of ≤0.1% and a load regulation rate of ≤0.5%.

[0062] According to the DC isolation circuit and power device provided in the present application, an isolation transformer is provided in the inverter circuit to increase the isolation voltage, and the feedback voltage is transmitted to the variable gain control circuit through the feedback winding of the isolation transformer through the feedback loop. The waveform gain of the third input terminal is controlled based on the voltage comparison between the first input terminal and the second input terminal of the variable gain control circuit, thereby realizing closed-loop regulation of the DC isolation circuit and reducing the voltage regulation rate and load regulation rate.

[0063] The present application also provides an electric power device, comprising the DC isolation circuit as described above:

[0064] A waveform generator circuit 10 is connected to a power supply and configured to generate a waveform signal;

[0065] an amplifying and filtering circuit 20 for amplifying and filtering the waveform signal output by the waveform generator circuit 10;

[0066] A variable gain control circuit 30 includes a first input terminal, a second input terminal, and a third input terminal. The variable gain control circuit is used to control the waveform gain of the third input terminal based on a voltage comparison between the first input terminal and the second input terminal. The first input terminal is used to obtain a ground voltage, the second input terminal is used to obtain a feedback voltage, and the third input terminal is connected to the output terminal of the waveform generator circuit 10 via the amplifying and filtering circuit 20 to obtain a waveform signal.

[0067] The driving circuit 40 is used to amplify and shape the waveform signal output by the variable gain control circuit 30;

[0068] an inverter circuit 50 connected to the output end of the variable gain control circuit 30 via the drive circuit 40 , the inverter circuit including an isolation transformer, the isolation transformer including a magnetic core, a primary winding, a secondary winding, and a feedback winding, the secondary winding being used to output a voltage, and the feedback winding being used to output a feedback voltage;

[0069] A feedback loop 60 , wherein the feedback winding is connected to the input end of the feedback loop 60 after rectification, and the output end of the feedback loop 60 is connected to the second input end of the variable gain control circuit 30 ;

[0070] The output circuit 70 is connected to the secondary winding and is used to rectify the waveform signal output by the secondary winding to output a floating voltage.

[0071] In one embodiment, the compact isolation transformer used in the DC isolation circuit significantly reduces the overall size of the power device. The power device's housing is made of aluminum alloy, offering excellent heat dissipation and electromagnetic interference resistance. The power device's interior utilizes a modular design, with each module independently separated for easy maintenance and replacement.

[0072] In one embodiment, a power device including the aforementioned DC isolation circuit has broad application in semiconductor devices, medical equipment, and other applications requiring ultrahigh-voltage DC isolation circuits. In these technical fields, the use of suspended overvoltage power supply technology can provide a stable and low-noise high-voltage power supply, which is crucial for precise control and image acquisition of precision equipment. Application of this power device can improve the reliability and safety of these devices.

[0073] It should be noted that the above application fields are only exemplary and this application does not limit them.

[0074] Please note that the above embodiments are for illustrative purposes only and are not intended to limit the present application.

[0075] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0076] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A DC isolation circuit, characterized in that: include: A waveform generator circuit is connected to a power supply, and is used to generate a waveform signal; an amplifying and filtering circuit, used for amplifying and filtering the waveform signal output by the waveform generator circuit; a variable gain control circuit, comprising a first input terminal, a second input terminal, and a third input terminal, the variable gain control circuit being configured to control the waveform gain of the third input terminal based on a voltage comparison between the first input terminal and the second input terminal, wherein the first input terminal is configured to obtain a ground voltage, the second input terminal is configured to obtain a feedback voltage, and the third input terminal is connected to the output terminal of the waveform generator circuit via the amplifying and filtering circuit to obtain the waveform signal; A driving circuit, configured to amplify and shape the waveform signal output by the variable gain control circuit; an inverter circuit connected to the output end of the variable gain control circuit via the drive circuit, the inverter circuit comprising an isolation transformer, the isolation transformer comprising a magnetic core, a primary winding, a secondary winding, and a feedback winding, the secondary winding being configured to output a voltage, and the feedback winding being configured to output the feedback voltage; the primary winding and the secondary winding being respectively disposed on opposite sides of the magnetic core, and the distance between the primary winding and the secondary winding being configured to adjust the isolation voltage of the DC isolation circuit; A feedback loop, wherein the magnetic flux change of the feedback winding is collected and rectified and then connected to the input end of the feedback loop, and the output end of the feedback loop is connected to the second input end of the variable gain control circuit; The output circuit is connected to the secondary winding and is used to rectify the waveform signal output by the secondary winding to output a floating voltage.

2. The DC isolation circuit according to claim 1, characterized in that: The feedback winding is arranged outside the secondary winding.

3. The DC isolation circuit according to claim 1, characterized in that: Based on adjusting the distance between the secondary winding and the feedback winding, the isolation voltage of the DC isolation circuit is adjusted.

4. The DC isolation circuit according to claim 1, characterized in that: The isolation voltage range of the DC isolation circuit includes 50kV to 150kV.

5. The DC isolation circuit according to claim 1, characterized in that: The skeletons of the primary winding, the secondary winding and the feedback winding are made of tetrafluoroethylene material.

6. The DC isolation circuit according to claim 1, characterized in that: The voltage processing circuit in the feedback loop includes a voltage divider circuit, an operational amplifier, a differential operation circuit and a filter circuit arranged in sequence, which is used to perform voltage division, operational amplification, differential operation and filtering on the feedback voltage and the power supply voltage in sequence. After being processed by the feedback loop, the feedback voltage is input into the second input end of the variable gain control circuit.

7. The DC isolation circuit according to claim 6, characterized in that: The variable gain control circuit includes a variable gain amplifier, a first pin of the variable gain amplifier is grounded and serves as the first input terminal, a second pin of the variable gain amplifier is connected to the voltage processing circuit in the feedback loop to obtain the processed feedback voltage, a third pin of the variable gain amplifier is connected to the output terminal of the amplifying and filtering circuit, and the input terminal of the amplifying and filtering circuit is connected to the output terminal of the waveform generator circuit.

8. The DC isolation circuit according to claim 1, characterized in that: The waveform of the waveform signal includes a sine wave.

9. An electric power device, characterized in that: The DC isolation circuit comprises the DC isolation circuit according to any one of claims 1 to 8.

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