Direct current isolation circuit and power device

Abstract

The invention provides a DC isolation circuit and a power device, and the circuit comprises a waveform generator circuit which is connected to a power supply and is used for transmitting a waveform signal; the variable gain control circuit comprises a first input end, a second input end and a third input end and is used for controlling waveform gain of the third input end based on voltage comparison of the first input end and the second input end, the first input end is used for acquiring grounding voltage, and the second input end is used for acquiring feedback voltage. The third input end is connected to the output end of the waveform generator circuit through the amplification filter circuit to obtain a waveform signal; the inverter circuit is connected to the output end of the variable gain control circuit through the driving circuit and comprises an isolation transformer, the isolation transformer comprises a magnetic core, a primary winding, a secondary winding and a feedback winding, the secondary winding is used for outputting voltage, and the feedback winding is connected to a feedback loop after being rectified. The feedback loop is connected to the second input end of the variable gain control circuit. The isolation voltage is improved, and the voltage and load regulation rate is reduced.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a direct current 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. The existing high-voltage DC isolation circuit uses photoelectric isolation technology, which converts optical signals into electrical signals to achieve isolation between high-voltage and low-voltage circuits. However, it is only suitable for scenarios with low isolation voltage (about 3kV~5kV), and usually requires repeated voltage and load adjustments. Summary of the invention

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

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

[0006] A waveform generator circuit is connected to a power supply, and the waveform generator circuit is used to generate 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, comprising a first input terminal, a second input terminal and a third input terminal, wherein 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, 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 an output terminal of a 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 is connected to the output end of the variable gain control circuit via a drive circuit, the inverter circuit includes an isolation transformer, the isolation transformer includes a magnetic core, a primary winding, a secondary winding and a feedback winding, the secondary winding is used to output a voltage, and the feedback winding is 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 a 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 suspension 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. The feedback voltage is input into the second input terminal of the variable gain control circuit after being processed by the feedback loop.

[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 a 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 the load regulation rate. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0026] Figure 3 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 an 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. Amplification and filtering 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] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

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

[0033] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", 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 may be changed arbitrarily, and the component layout type may also be more complicated.

[0035] The present 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, connected to a power supply, the waveform generator circuit is used to generate a waveform signal;

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

[0038] A variable gain control circuit 30, comprising a first input terminal, a second input terminal and a third input terminal, wherein 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, 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 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 is used to output a voltage, and the feedback winding is used 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 only needs to be supplied with a DC power supply, and can oscillate and generate a waveform signal by itself without an external signal, such as a sine wave, a triangle wave, a square wave, a rectangular wave, etc. The selection of the generated waveform can determine whether the entire DC isolation circuit can work in a high-demand situation. 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, which will 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 normal operation of the communication system, and causing information loss. Preferably, the waveform signal emitted by the waveform generator circuit 10 is a sine wave to avoid generating high-order harmonics, thereby avoiding damage to the power system and the 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 a resistor R1, a resistor R3 and a capacitor C8 to form a 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 the 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 the pin 7 (DISCH) of the waveform generator U1, the second end of the resistor R3 is connected to the 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; the pin 6 (THRES) of the waveform generator U1 is connected to the pin 2 (TRIG) of the waveform generator U1; Pin 5 (CONT) of waveform generator U1 is grounded via capacitor C3; Pin 1 (GND) of waveform generator U1 is grounded; Pin 3 (OUT) of waveform generator U1 is grounded 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, capacitor C2 and capacitor C3 are filter capacitors, and resistor R2 is a pull-up resistor. The first end of capacitor C7 is connected to pin 3 (OUT) of waveform generator U1 via capacitor C1, the second end of capacitor C7 is grounded, capacitor C1 and capacitor C7 can optimize the waveform, and resistor R7 limits the output.

[0045] Please continue to refer to Figure 2 The filter circuit includes a filter circuit composed of a resistor R6, a capacitor C6, a resistor R5, a capacitor C5, a resistor R4, and a capacitor C4, so that the waveform of the emitted sine wave is more standard. The first end of the capacitor C6 is connected to the first end of the capacitor C7 via the resistor R6, and the second end of the capacitor C6 is grounded. The first end of the capacitor C5 is connected to the first end of the capacitor C6 via the resistor R5, and the second end of the capacitor C5 is grounded; the first end of the capacitor C4 is connected to the first end of the capacitor C5 via the resistor R4, and the second end of the 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, wherein 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, and an 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, the variable gain amplifier U2 includes 8 pins, wherein pin 1 (GPOS) is grounded as the first input terminal of the variable gain control circuit 30 to obtain the ground voltage, pin 2 (GNEG) is connected to the feedback winding of the inverter circuit 50 via the feedback loop 60 as the second input terminal of the variable gain control circuit 30 to obtain the feedback voltage after rectification, and pin 3 (VINP) is connected to the output terminal of the waveform generator circuit 10 via the amplification and filtering circuit 20 as the third input terminal of the variable gain control circuit 30 to obtain the waveform signal. The variable gain amplifier U2 compares the ground voltage of pin 1 with the feedback voltage of pin 2, and controls the gain of the waveform of pin 3 according to the comparison data, that is, the waveform input to pin 3 is amplified or reduced, and the amplified or reduced waveform is output to the input terminal of the drive circuit 40 through pin 5 (FDBK) and pin 7 (VOUT) of the variable gain amplifier U2.

[0049] In one embodiment, Figure 3As shown, the feedback loop 60 includes a voltage divider circuit for feedback voltage and an operational amplifier U3. Specifically, the voltage divider circuit of the feedback voltage VF includes a resistor R10 and a resistor R11 connected in series, the first end of the resistor R10 is connected to the feedback voltage VF and the second end is connected to the first end of the resistor R11, and the second end of the resistor R11 is grounded; the first input end ("+" input end or positive input end) of the operational amplifier U3 is connected to the second end of the resistor R10, the second input end ("-" input end or negative input end) of the operational amplifier U3 is connected to the output end of the operational amplifier U3, and the output end of the operational amplifier U3 is connected to the positive input end of the differential operator U5 via a resistor R14. Since the driving ability of the feedback voltage is weak, after the voltage is divided by the voltage divider circuit, the driving ability of the feedback voltage is improved by following the operational amplifier U3. The 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 the power supply voltage VDD includes a resistor R8 and a resistor R9 connected in series, wherein the first end of the resistor R8 is connected to the voltage VDD, the second end of the resistor R8 is connected to the first end of the resistor R9, the second end of the resistor R9 is grounded, and the second end of the resistor R9 is also connected to the positive input end of the operational amplifier U4 via the capacitor C9; the first input end ("+" input end or positive input end) of the operational amplifier U4 is connected to the second end of the resistor R8, and the second input end ("-" input end or reverse input end) of the operational amplifier U4 is connected to the output end of the operational amplifier U4. After the voltage VDD is divided by the voltage divider circuit, it is followed by the operational amplifier U4. The feedback loop 60 also includes a differential operation circuit, which includes a differential operator U5, a resistor R12, a resistor R13, a resistor R14, and a resistor R15. The second input terminal ("-" input terminal or reverse input terminal) of the differential operator U5 is connected to the output terminal of the operational amplifier U4 via the resistor R12. The second input terminal of the differential operator U5 is also connected to the output terminal of the differential operator U5 via the resistor R13. The first input terminal ("+" input terminal or positive input terminal) of the differential operator U5 is grounded (GND) via the resistor R15. The output terminal of the operational amplifier U3 is connected to the first input terminal of the differential operator U5 via the resistor R14. The differential operator U5 performs differential operation on the voltages followed by the operational amplifier U4 and the operational amplifier U3 to obtain a processed feedback voltage, so that the feedback voltage is more accurate. The filtering circuit includes a resistor R16 and a capacitor C10, and the output end of the differential operator U5 is connected to pin 2 (GNEG) of the variable gain amplifier U2 via the resistor R16; wherein the first end of the resistor R16 is connected to the output end of the differential operator U5, the second end of the resistor R16 is connected to pin 2 (GNEG) of the variable gain amplifier U2, and 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 the variable gain amplifier U2 is grounded, and pin 1 (GPOS) of the variable gain amplifier U2 is connected to pin 4 (COMM) of the variable gain amplifier U2; pin 3 (GPOS) of the variable gain amplifier U2 is grounded via resistor R17, and pin 3 (GPOS) of the variable gain amplifier U2 is also connected to the amplification and filtering circuit 20 via capacitor C11. The variable gain amplifier U2 compares the acquired ground voltage with the feedback voltage acquired by pin 2 (GNEG), and according to the comparison data, the chip realizes internal variable gain (amplification factor), and then amplifies or reduces the waveform input to pin 3 (VINP) according to the amplification factor of the variable gain amplifier U2, and outputs it through pin 5 (FDBK) and pin 7 (VOUT) of the variable gain amplifier U2. Specifically, the ground voltage at 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 the variable gain amplifier U2 is further connected to the operational amplifier U6. Specifically, the pin 5 (FDBK) of the variable gain amplifier U2 is connected to the pin 7 (VOUT) of the variable gain amplifier U2. The pin 7 (VOUT) of the variable gain amplifier U2 is connected to the first input ("+" input or positive input) of the operational amplifier U6 via the capacitor C12 and the resistor R0, wherein the connection node of the capacitor C12 and the resistor R0 is grounded (GND) via the resistor R18; the second input ("-" input or reverse input) of the operational amplifier U6 is connected to the output of the operational amplifier U6, and the output of the operational amplifier U6 is connected to the drive circuit 40. The drive waveform is output to the drive circuit 40 through the operational amplifier U6, thereby obtaining a voltage regulation rate of ≤0.1%; and a load regulation rate of ≤0.5%, and the entire system is balanced.

[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 switch circuit and an isolation transformer. Among them, the switch circuit includes a switch tube U7 and a switch tube U8, the drive circuit 40 is connected to the control end of the switch tube U7 via a resistor R19, and the drive circuit 40 is connected to the control end of the switch tube U8 via a resistor R20. The switch tube U7 and the switch tube U8 are connected to the primary winding of the isolation transformer, wherein the first end of the switch tube U7 is connected to the first end of the primary winding, the second end of the switch tube U7 is connected to the first end of the switch tube U8, the second end of the switch tube U8 is connected to the fourth end of the primary winding, and the connection node of the second and third ends of the primary winding is grounded (GND) via a capacitor C0, and the connection node of the second and third ends of the primary winding is also connected to a voltage VCC, and the connection node of the voltage VCC and the capacitor C0 is grounded via a capacitor Cs. The drive circuit 40 switches the switch tubes U7 and U8 through resistors R19 and R20 to cause the isolation transformer to invert.

[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 both sides of the magnetic core 501, wherein the primary winding 502 is arranged on the power supply side of the magnetic core 501, and the primary winding 502 is also called the primary winding, and the secondary winding 503 is arranged on the load side of the magnetic core 501, and the secondary winding 503 is also called the secondary winding. Further, the primary winding 502 and the secondary winding 503 are both arranged on the outside of the magnetic core 501, and the feedback winding 504 is arranged on the outside of the secondary winding 503. The isolation voltage value is increased by winding the primary winding and the secondary winding on both sides of the magnetic core.

[0056] Exemplarily, by adjusting the distance between the secondary winding 503 and the primary winding 502, the isolation voltage of the DC isolation circuit can be adjusted. Exemplarily, by adjusting the distance between the secondary winding 503 and the feedback winding 504, the isolation voltage of the DC isolation circuit can be adjusted. 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, such as replacing the magnetic core 501 or using a magnetic core 501 with adjustable spacing on both sides. Since the feedback winding 504 is arranged on the outside of 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 magnetic 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, and tetrafluoroethylene is a high-voltage resistant material. The isolation transformer is used to separate the high-voltage part from the low-voltage part, reduce the risk of electromagnetic interference and high-voltage leakage, and increase the isolation voltage. Compared with the use of optical coupling, 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 by the feedback loop after rectification. Figure 4As shown, after the drive circuit 40 switches the switch tube U7 and the switch tube U8 through the resistor R19 and the resistor R20 to invert the isolation transformer, the high-frequency voltage output by the secondary winding of the isolation transformer is full-wave rectified by the diode D1 and the diode D2 according to the turns ratio of the isolation transformer, 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 terminal and the 7th terminal 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; the cathode of the diode D2 is also connected to the cathode of the diode D1. The signal after being inverted by the switch tube U7, the switch 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 the filter circuit composed of the capacitor C15, the capacitor C16, the inductor U9, the capacitor C17 and the capacitor C18 performs the П-type filtering. 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 a 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 end of the feedback winding is connected to the feedback voltage VF via the diode D3, the resistor R24, and the resistor R25; the first end of the resistor R24 ​​is connected to the cathode of the diode D3, the second end of the resistor R24 ​​is connected to the first end of the resistor R25, and the second end of the resistor R24 ​​is also connected to the ground (GND) via the capacitor C19; the first end of the capacitor C20 is connected to the second end of the resistor R24, and the second end of the capacitor C20 is connected to the ground (GND); the first end of the capacitor C21 is connected to the second end of the resistor R25, and the second end of the capacitor C21 is connected to the ground (GND); the first end of the capacitor C22 is connected to the feedback voltage VF, and the second end of the capacitor C22 is connected to the ground (GND). The first end of the feedback loop 60 is connected to the feedback voltage VF, and the second end of the feedback loop 60 is connected to the variable gain control circuit 30.

[0060] Please continue to refer to Figure 4In one embodiment, if Figure 4 As shown, in order to accurately collect the feedback voltage of the feedback winding of the isolation transformer and ensure that the feedback voltage transmitted to the second input terminal of the variable gain control circuit 30 can accurately reflect the change of the output voltage "VOUT" with the load to adjust the system, the output current should be avoided from flowing through the feedback winding. As the output current changes, the magnetic flux of the feedback winding is collected. Since the induced electromotive force E≈dФ / dt, the induced electromotive force E is opposite to the feedback terminal voltage U, so half-wave rectification is performed through the diode D3, and the resistor R24, the resistor R25 and the capacitor C19, the capacitor C20, the capacitor C21, and the capacitor C22 are filtered and transmitted to the feedback loop 60. The feedback loop 60 determines the feedback output voltage according to the received feedback voltage, and the feedback output voltage is then transmitted to the variable gain control circuit 30 to control the output gain of the circuit, thereby controlling the output of the drive circuit 40, so that the entire DC isolation circuit operates in a closed-loop, efficient and steady-state state. In this way, the voltage regulation rate ≤0.1% and the load regulation rate ≤0.5% can be obtained.

[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 to output a floating voltage. The other feedback voltage is output to the feedback loop 60 through the feedback winding through the RC rectification. It is first divided by the voltage divider circuit to avoid the feedback voltage being too high, and then is operated. The operational amplifier U3 follows to improve the driving capability of the feedback voltage, and then the power supply voltage and the feedback voltage are differentiated through the differential operator U5 to make the feedback voltage more accurate, and then low-pass filtering is performed through the resistor R16 and the capacitor C10. The waveform after the above processing 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 waveform gain multiple of 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 end 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 a 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 the load regulation rate.

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

[0064] A waveform generator circuit 10, connected to a power supply, the waveform generator circuit is used to generate a waveform signal;

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

[0066] A variable gain control circuit 30, comprising a first input terminal, a second input terminal and a third input terminal, wherein 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, 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 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] The inverter circuit 50 is connected to the output end of the variable gain control circuit 30 via the drive circuit 40. The inverter circuit includes an isolation transformer. The isolation transformer includes a magnetic core, a primary winding, a secondary winding and a feedback winding. The secondary winding is used to output a voltage, and the feedback winding is 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 isolation transformer used in the DC isolation circuit is small in size, so the overall size of the power device is greatly reduced. The shell of the power device is made of aluminum alloy material, which has good heat dissipation and anti-electromagnetic interference performance. The power device adopts a modular design inside, and each module is independently separated for easy maintenance and replacement.

[0072] In one embodiment, the power device including the DC isolation circuit is widely used in semiconductor equipment, medical equipment and other application fields that require ultra-high 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. The application of the power device can improve the reliability and safety of the equipment.

[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-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A DC isolation circuit, characterized in that: include: A waveform generator circuit connected to a power supply, wherein the waveform generator circuit 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, wherein 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, 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 the amplifying and filtering circuit to obtain the waveform signal; A driving circuit, used for amplifying and shaping 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 is used to output a voltage, and the feedback winding is used to output the feedback voltage; 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; 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 suspension voltage.

2. The DC isolation circuit according to claim 1, characterized in that: 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.

3. The DC isolation circuit according to claim 1, characterized in that: Adjusting the isolation voltage of the DC isolation circuit based on adjusting the distance between the secondary winding and the primary winding; and / or 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~150kV.

5. The DC isolation circuit according to claim 1, characterized in that: The frames 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 which are arranged in sequence, and is used to perform voltage division, operational amplification, differential operation and filtering on the feedback voltage and the power supply voltage in sequence. The feedback voltage is input into the second input terminal of the variable gain control circuit after being processed by the feedback loop.

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 a voltage processing circuit in the feedback loop to obtain the processed feedback voltage, a third pin of the variable gain amplifier is connected to an output terminal of the amplifying and filtering circuit, and an input terminal of the amplifying and filtering circuit is connected to an 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 invention comprises the DC isolation circuit according to any one of claims 1 to 8.

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