Feedback voltage stabilization output isolation circuit

Abstract

The utility model discloses a feedback voltage stabilization output isolation circuit, which comprises a power supply circuit, a control regulation circuit, an isolation output circuit and a differential amplification circuit, the power supply circuit is respectively and electrically connected with the control regulation circuit and the isolation output circuit, and the control regulation circuit is respectively and electrically connected with the isolation output circuit and the differential amplification circuit. The isolation output circuit comprises a transformer T1, the transformer T1 is provided with a winding N1, a winding N2, a winding N3 and a winding N4, the winding N1 is electrically connected with the power supply circuit, and the winding N2, the winding N3 and the winding N4 output electric energy outwards. The transformer is used for circuit isolation, temperature limitation can be avoided, the distance between the two isolated circuits can be shortened, and the size of the switching power supply is further reduced; the differential amplification circuit is arranged to amplify the voltage output to the differential amplification circuit from the isolation output circuit to obtain an amplified stable signal, and then the signal is input into the control regulation circuit for internal regulation and compensation, so that the voltage can be stably output to the winding N1 finally, and the winding N3 and the winding N4 are enabled to stably output the voltage to the outside.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, specifically to a feedback-regulated output isolation circuit. Background Technology

[0002] In a switching power supply, there are high-voltage and low-voltage circuits. The ground wires for these circuits are often different, necessitating isolation between them. This is because when the high-voltage and low-voltage circuits of a switching power supply do not share a common ground, their potential differences become different. To prevent the high voltage or interference noise from the high-voltage circuit from being transmitted to other circuits and affecting other electronic components or the safety of the user, electrical isolation measures are required to separate the high-voltage and low-voltage circuits.

[0003] like Figure 1 As shown, in the circuit connecting primary side terminals 1 and 2 of optocoupler U2 to secondary side terminals 3 and 4, the ground wire connected to primary side terminals 1 and 2 is GND, while the ground wire connected to secondary side terminals 3 and 4 is BGND. Because the ground wires are different, the potential difference between them is also different. Since the primary circuit voltage in the circuit connected to primary side terminals 1 and 2 is 12V, while the MCU chip UC3845BN is connected in the circuit of secondary side terminals 3 and 4, the operating voltage of the secondary circuit does not need to be too high to avoid burning out the MCU chip. Therefore, to prevent mutual interference between the primary and secondary circuits, each circuit usually needs to be designed and protected independently. Furthermore, to stabilize the output voltage of primary side terminals 1 and 2, optocoupler feedback is usually used to adjust the circuit compensation of secondary side terminals 3 and 4 to achieve a stable output voltage on the primary side. However, the use of optocoupler U2 for electrical isolation occupies more space, which increases the size of the switching power supply. In addition, the operating temperature range is limited, and it may not work properly in extreme ambient temperatures, resulting in significant limitations in its operation. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a feedback-regulated output isolation circuit.

[0005] The objective of this utility model is achieved through the following solution:

[0006] A feedback-regulated output isolation circuit includes: a power supply circuit, a control and regulation circuit, an isolation output circuit, and a differential amplifier circuit. The power supply circuit is electrically connected to the control and regulation circuit and the isolation output circuit, respectively. The control and regulation circuit is electrically connected to the isolation output circuit and the differential amplifier circuit, respectively. The isolation output circuit includes a transformer T1, which has windings N1, N2, N3, and N4. Winding N1 is electrically connected to the power supply circuit, and windings N2, N3, and N4 output electrical energy to the outside.

[0007] In one embodiment, the isolated output circuit further includes a first freewheeling protection module and a first current limiting filter module. The winding N2 is electrically connected to the first freewheeling protection module, and the first freewheeling protection module is electrically connected to the first current limiting filter module and outputs DC voltage to the outside.

[0008] In one embodiment, the isolated output circuit further includes a second freewheeling protection module, a third freewheeling protection module, a first filter module, and a second filter module. Winding N3 is electrically connected to the second freewheeling protection module, and the second freewheeling protection module outputs voltage V+ after being electrically connected to the first filter module. Winding N4 is electrically connected to the third freewheeling protection module, and the third freewheeling protection module outputs voltage V- after being electrically connected to the second filter module. The first filter module is also electrically connected to the second filter module.

[0009] In one embodiment, the power supply circuit includes a power supply, a fourth freewheeling protection module, a second current limiting filter module, a third filter module, a third current limiting filter module, and a fifth freewheeling protection module. The power supply is electrically connected to the fourth freewheeling protection module. The fourth freewheeling protection module is electrically connected to the second and third current limiting filter modules, respectively. The second and third current limiting filter modules are electrically connected to the control and regulation circuit, respectively. The third filter module is electrically connected to the control and regulation circuit, respectively. The third current limiting filter module is electrically connected to the fifth freewheeling protection module and the winding N1, respectively. The fifth freewheeling protection module is electrically connected to the control and regulation circuit.

[0010] In one embodiment, the control and adjustment circuit includes a control chip and a first switch module. The control chip has terminals 1 to 8. The first switch module is electrically connected to terminal 6 of the control chip, the power supply circuit, and the isolation output circuit, respectively. The differential amplifier circuit is electrically connected to terminal 1 of the control chip, and the power supply circuit is electrically connected to terminal 7 of the control chip.

[0011] In one embodiment, the control and adjustment circuit further includes a fourth filtering module, which is electrically connected to terminals 1, 2, 4 and 8 of the control chip, respectively. The fourth filtering module is also electrically connected to the first switching module and is grounded to GND.

[0012] In one embodiment, the control and regulation circuit further includes a fourth current limiting filter module, which is electrically connected to terminal 3 of the control chip and the first switch module, respectively. The fourth current limiting filter module is also grounded to GND.

[0013] In one embodiment, the control and regulation circuit further includes an oscillation module, which is electrically connected to terminal 8 of the control chip.

[0014] In one embodiment, the control and regulation circuit further includes a first current limiting protection module, which is electrically connected to terminal 6 of the control chip and the first switch module, respectively. The first current limiting protection module is also grounded to GND.

[0015] In one embodiment, the differential amplifier circuit includes a second current-limiting protection module, a fifth current-limiting filter module, a feedback compensation module, an operational amplifier, a first output protection module, a pull-down module, a second switching module, and a second output protection module. The second current-limiting protection module has an input voltage of DC. The second current-limiting protection module is electrically connected to the fifth current-limiting filter module, the feedback compensation module, and the operational amplifier, respectively. The second current-limiting protection module is also grounded (BGND). The fifth current-limiting filter module is also grounded (BGND). The feedback compensation module is electrically connected to the first output protection module. The first output protection module is electrically connected to the pull-down module. The pull-down module is electrically connected to the second switching module and is also grounded (BGND). The second switching module is electrically connected to the second output protection module and is also grounded. The second output protection module is electrically connected to the control and adjustment circuit.

[0016] Compared with the prior art, the present invention has at least the following advantages:

[0017] This invention discloses a feedback-regulated output isolation circuit. By employing a transformer for circuit isolation, the transformer's use is not limited by temperature, and the distance between the two isolated circuits is shortened, further reducing the size of the switching power supply. Simultaneously, a differential amplifier circuit is included to amplify the voltage output from the isolated output circuit, thereby obtaining a stable amplified signal. This amplified signal is then input to the control and regulation circuit for internal adjustment and compensation, enabling the control and regulation circuit to stably output voltage to winding N1, and ensuring stable external output voltage from windings N3 and N4. Attached Figure Description

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0019] Figure 1 This is a circuit diagram of an isolation circuit in the prior art;

[0020] Figure 2 This is a feedback-regulated output isolation circuit of the present invention;

[0021] In the attached diagram, the reference numerals are as follows: 1. Power supply circuit; 11. Power supply; 12. Fourth freewheeling protection module; 13. Second current limiting filter module; 14. Third filter module; 15. Third current limiting filter module; 16. Fifth freewheeling protection module;

[0022] 2. Control and regulation circuit; 21. Control chip; 22. First switching module; 23. Fourth filtering module; 24. Fourth current limiting filtering module; 25. Oscillation module; 26. First current limiting protection module;

[0023] 3. Isolation output circuit; 31. Transformer T1; 32. First freewheeling protection module; 33. First current limiting filter module; 34. Second freewheeling protection module; 35. Third freewheeling protection module; 36. First filter module; 37. Second filter module;

[0024] 4. Differential amplifier circuit; 41. Second current limiting protection module; 42. Fifth current limiting filter module; 43. Feedback compensation module; 44. Operational amplifier; 45. First output protection module; 46. Pull-down module; 47. Second switch module; 48. Second output protection module. Detailed Implementation

[0025] The following drawings will disclose several embodiments of this utility model. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this utility model. That is, in some embodiments of this utility model, these practical details are not essential. In addition, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0026] It should be noted that all directional indicators in this utility model embodiment, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indicator will also change accordingly.

[0027] Furthermore, in this utility model, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the utility model. They are merely used to distinguish components or operations described with the same technical terms and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0028] To further understand the utility model's content, features, and effects, the following embodiments are provided, along with detailed descriptions in conjunction with the accompanying drawings:

[0029] like Figure 2 As shown, this utility model provides a feedback voltage regulation output isolation circuit, including: a power supply circuit 1, a control and adjustment circuit 2, an isolation output circuit 3, and a differential amplifier circuit 4. The power supply circuit 1 is electrically connected to the control and adjustment circuit 2 and the isolation output circuit 3, respectively. The control and adjustment circuit 2 is electrically connected to the isolation output circuit 3 and the differential amplifier circuit 4, respectively.

[0030] The power supply circuit 1 provides power to the control and regulation circuit 2 and the isolation output circuit 3. The control and regulation circuit 2 can be used to adjust the compensation voltage supplied to the isolation output circuit 3, so that the isolation output circuit 3 can output a stable voltage to the electrical equipment connected to the isolation output circuit 3 during operation. When the feedback regulated output isolation circuit is working, the isolation output circuit 3 has a primary side and a secondary side. The power supply circuit 1 is electrically connected to the primary side to provide power to the isolation output circuit 3, and the secondary side outputs voltage to provide power to the connected electrical equipment. At the same time, the secondary side can also feed power back to the differential amplifier circuit 4. The differential amplifier circuit 4 can amplify the voltage fed back from the secondary side of the isolation output circuit 3 and then re-input it into the control and regulation circuit 2 to adjust the voltage. The voltage is adjusted to a suitable compensation value and then sent to the isolation output circuit 3, so that it can accurately and stably output voltage to the electrical equipment during operation.

[0031] Specifically, the isolation output circuit 3 includes a transformer T1 31, which has windings N1, N2, N3, and N4. Winding N1 is electrically connected to the power supply circuit 1, and windings N2, N3, and N4 output electrical energy to the outside. Among them, winding N1 is the primary side, and windings N2, N3, and N4 are the secondary sides. Winding N1 has terminal 1 and terminal 2, which are electrically connected to the power supply circuit 1. The power supply circuit 1 provides electrical energy to the isolation output circuit 3 through winding N1. Winding N2 feeds the electrical energy back to the differential amplifier circuit 4. Windings N3 and N4 are voltage output circuits. When the feedback voltage regulation output isolation circuit is working, windings N3 and N4 are electrically connected to the electrical equipment and output electrical energy to the electrical equipment. In this embodiment, the turns ratio of the winding coils is 1:1:1:1.

[0032] Specifically, the isolated output circuit 3 also includes a first freewheeling protection module 32 and a first current limiting filter module 33. The winding N2 is electrically connected to the first freewheeling protection module 32. After the first freewheeling protection module 32 and the first current limiting filter module 33 are electrically connected, they also output DC voltage. Among them, the winding N2 has terminal 3 and terminal 4; the first freewheeling protection module 32 includes a diode D17, which has terminal 1 and terminal 2; the first current limiting filter module 33 includes a resistor R22, a capacitor C30, and a capacitor C31, which each have terminal 1 and terminal 2.

[0033] It should be noted that terminal 3 of winding N2 is electrically connected to terminal 1 of diode D17, while terminal 4 of winding N2 is grounded (BGND). Terminal 2 of diode D17 outputs DC voltage. Terminals 1 and 2 of resistor R22, capacitor C30, and capacitor C31 are connected in parallel, and terminal 1 of the parallel connection is electrically connected to terminal 2 of diode D17. During operation, since winding N1 is electrically connected to power supply circuit 1, when power supply circuit 1 supplies power to winding N1, winding N1 generates an induced electromotive force, causing the induced current in the primary winding to increase. When power supply circuit 1 stops supplying power to winding N1, the inductance within winding N1 generates a reverse induced electromotive force, releasing the stored electrical energy, energizing winding N2, and causing it to output DC voltage. In this design, diode D17 directs the output voltage of winding N2 to the DC terminal to prevent reverse current from the induced electromotive force generated by the self-inductance of winding N2; resistor R22 acts as a current-limiting resistor to prevent excessive output current; capacitors C30 and C31 serve as filter capacitors. Since the circuit of winding N2 is a flyback circuit, it generates considerable ripple noise; therefore, capacitors C30 and C31 are used for filtering. In this embodiment, capacitor C31 is an electrolytic capacitor, which has strong ripple resistance, thus providing better filtering of the output DC voltage.

[0034] Specifically, such as Figure 2As shown, the isolated output circuit 3 includes a second freewheeling protection module 34, a third freewheeling protection module 35, a first filter module 36, and a second filter module 37. The winding N3 is electrically connected to the second freewheeling protection module 34, and the second freewheeling protection module 34 outputs a voltage V+ after being electrically connected to the first filter module 36. The winding N4 is electrically connected to the third freewheeling protection module 35, and the third freewheeling protection module 35 outputs a voltage V- after being electrically connected to the second filter module 37. The first filter module 36 is also electrically connected to the second filter module 37. Among them, winding N3 has terminals 5 and 6, and winding N4 has terminals 7 and 8; the second freewheeling protection module 34 includes diode U14, and the third freewheeling protection module 35 includes diode U16. Transistors U14 and U16 each have terminals 1 and 2, respectively; the first filter module 36 includes capacitors C26 and C27, and the second filter module 37 includes capacitors C28 and C29. Capacitors C26, C27, C28, and C29 each have terminals 1 and 2, respectively. In this example, voltage V+ and voltage V- are +12V and -12V, respectively.

[0035] It should be noted that terminal 5 of winding N3 is electrically connected to terminal 1 of diode U14, and terminal 2 of diode U14 outputs voltage V+. Terminal 8 of winding N4 is electrically connected to terminal 2 of diode U16, and terminal 1 of diode U16 outputs voltage V-. Terminal 6 of winding N3 and terminal 7 of winding N4 are electrically connected and grounded to GND. Terminals 1 and 2 of capacitors C26 and C27 are connected in parallel, and terminals 1 and 2 of capacitors C28 and C29 are connected in parallel. Terminals 1 of capacitors C26 and C27 are electrically connected to terminal 2 of diode U14. Terminals 2 of capacitors C26 and C27 are electrically connected to terminals 1 of capacitors C28 and C29. Terminals 2 of capacitors C28 and C29 are electrically connected to terminal 1 of diode U16. In practical operation, the DC voltage output from winding N2 is amplified by differential amplifier circuit 4, then input to control and regulation circuit 2 for control and regulation, and finally output back to power supply circuit 1 to re-compensate winding N1, so that windings N3 and N4 output the same voltage values ​​V+ and V-. The induced electromotive force generated by the self-inductance of windings N3 and N4 is prevented by diodes U14 and U16 from causing reverse induced current. Capacitors C26, C27, C28, and C29 act as filters, filtering the output voltages V+ and V- to reduce voltage noise interference.

[0036] Specifically, such as Figure 2As shown, the power supply circuit 1 includes a power supply 11, a fourth freewheeling protection module 12, a second current limiting filter module 13, a third filter module 14, a third current limiting filter module 15, and a fifth freewheeling protection module 16. The power supply 11 is electrically connected to the fourth freewheeling protection module 12. The fourth freewheeling protection module 12 is electrically connected to the second current limiting filter module 13 and the third current limiting filter module 15, respectively. The second current limiting filter module 13 is electrically connected to the third filter module 15 and the control and regulation circuit 2, respectively. The third filter module 15 is electrically connected to the control and regulation circuit 2. The third current limiting filter module 15 is electrically connected to the fifth freewheeling protection module 16 and the winding N1, respectively. The fifth freewheeling protection module 16 is electrically connected to the control and regulation circuit 2. The fourth freewheeling protection module 12 includes a diode U12, which has terminals 1 and 2; the second current limiting filter module 13 includes a resistor R20 and a capacitor C24, which have terminals 1 and 2 respectively; the third filter module 14 includes a capacitor C22 and a capacitor C23, which have terminals 1 and 2 respectively; the third current limiting filter module 15 includes a resistor R21 and a capacitor C25, which have terminals 1 and 2 respectively; and the fifth freewheeling protection module 16 includes a diode U13, which has terminals 1 and 2.

[0037] It should be noted that power supply 11 is electrically connected to terminal 1 of diode U12. Terminal 2 of diode U12 is electrically connected to terminals 1 of resistor R20, capacitor C24, resistor R21, and capacitor C25 respectively. Terminal 2 of diode U12 is also electrically connected to terminal 1 of winding N1. Terminal 1 of resistor R20 is electrically connected to terminal 1 of capacitor C24. Terminal 2 of resistor R20 is electrically connected to terminals 1 of capacitors C22 and C23, as well as control and adjustment circuit 2 respectively. Terminal 2 of capacitor C24 is grounded to BGND. Terminals 1 and 2 of capacitors C22 and C23 are connected in parallel, and terminal 2 is grounded to BGND. Terminals 1 and 2 of resistor R21 and capacitor C25 are connected in parallel, and terminal 2 is electrically connected to terminal 1 of diode U13. Terminal 2 of diode U13 is electrically connected to terminal 2 of winding N1. In actual operation, the current from power supply 11 flows into terminal 1 of diode U12 and out through terminal 2, supplying power to control and regulation circuit 2 and winding N1 respectively. Resistor R20 acts as a current-limiting resistor to prevent excessive current from damaging the control and regulation circuit. Capacitors C22, C23, and C24 function the same as the capacitors mentioned above, and will not be described again here. In this example, capacitors C22 and C24 are electrolytic capacitors, similar in function to capacitor C31, and will not be described again here.

[0038] Furthermore, if Figure 2As shown, the control and adjustment circuit 2 includes a control chip 21 and a first switching module 22. The control chip 21 has terminals 1 to 8. The first switching module 22 is electrically connected to terminal 6 of the control chip 21, the power supply circuit 1, and the isolation output circuit 3, respectively. The differential amplifier circuit 4 is electrically connected to terminal 1 of the control chip 21, and the power supply circuit 1 is electrically connected to terminal 7 of the control chip 21. It should be noted that the first switching module 22 includes a MOSFET U11, which has a gate (G), a source (S), and a drain (D). The gate (G) is electrically connected to terminal 6 of the control chip 21, the source (S) is electrically connected to the first current limiting protection module 26, and the drain (D) is electrically connected to the power supply circuit 1. In operation, the control chip 21 can control the MOSFET U11 and the differential amplifier circuit 4. By turning the MOSFET U11 on and off, the voltage output of the isolation output circuit 3 can be adjusted, and the gain of the differential amplifier circuit 4 can be controlled. In this example, the control chip 21 is a UC3845BN.

[0039] Specifically, the control and adjustment circuit 2 also includes a fourth filter module 23. The fourth filter module 23 is electrically connected to terminals 1, 2, 4, and 8 of the control chip 21, respectively. The fourth filter module 23 is also electrically connected to the first switch module 22 and is grounded (GND). The fourth filter module includes capacitors C16, C17, and C21, each having terminal 1 and terminal 2. The fourth filter module 23 has the same function as the first filter module 315 and the second filter module 316, and will not be described further here.

[0040] Specifically, the control and regulation circuit 2 also includes a fourth current-limiting filter module 24. The fourth current-limiting filter module 24 is electrically connected to terminal 3 of the control chip 21 and the first switch module 22, respectively. The fourth current-limiting filter module 24 is also grounded (GND). The fourth current-limiting filter module 24 includes a capacitor C18 and a resistor R16, with terminals 1 and 2 respectively. The fourth current-limiting filter module 24 has the same function as the first current-limiting filter module 312, the second current-limiting filter module 13, and the third current-limiting filter module 15, and will not be described further here.

[0041] Specifically, the control and regulation circuit 2 further includes an oscillation module 25, which is electrically connected to terminal 8 of the control chip 21. The fourth current-limiting filter module 24 includes a resistor R14 and a capacitor C20, each having a terminal (1) and a terminal (2). The resistor R14 and capacitor C20 form an RC oscillation circuit, stabilizing the voltage within the control and regulation circuit 2 and the frequency of the output signal.

[0042] Specifically, the control and regulation circuit 2 further includes a first current-limiting protection module 26. The first current-limiting protection module 26 is electrically connected to terminal 6 of the control chip 21 and the first switch module 22, respectively. The first current-limiting protection module 26 is also grounded (GND). The first current-limiting protection module 26 includes resistors R17, R18, and R19, each having a terminal (1) and a terminal (2). The first current-limiting protection module 26 is used to prevent excessive current from flowing into the connected components, thus protecting them.

[0043] It should be noted that terminal 1 of capacitor C16 is electrically connected to terminal 8 of control chip 21 and terminal 1 of resistor R14, respectively; terminal 2 of capacitor C16 is electrically connected to terminal 2 of control chip 21 and grounded to BGND; terminal 1 of capacitor C17 is electrically connected to terminal 4 of control chip 21; terminal 2 of capacitor C17 is electrically connected to terminal 1 of capacitor C18 and grounded to BGND; terminals 1 and 2 of capacitor C21 are connected in parallel to the drain (D) and source (S) of MOSFET U11, respectively; terminal 1 of capacitor C21 is electrically connected to power supply circuit 1 and isolation output circuit 3, respectively; terminal 2 of capacitor C21 is electrically connected to terminal 2 of resistor R16 and terminal 1 of resistor R18, respectively. Electrical connections: Terminal 2 of capacitor C18 is electrically connected to terminal 2 of resistor C20, terminal 3 of the control chip, and terminal 1 of resistor R16, respectively; terminal 1 of resistor R16 is electrically connected to terminal 3 of the control chip; terminal 1 of resistor R14 is electrically connected to terminal 8 of the control chip, and terminal 2 of resistor R14 is electrically connected to terminal 1 of capacitor C20; terminal 2 of capacitor C20 is also electrically connected to terminal 3 of the control chip; terminal 1 of resistor R17 is electrically connected to terminal 6 of the control chip, and terminal 2 of resistor R17 is electrically connected to the gate G of the MOSFET and terminal 1 of resistor R19, respectively; terminal 2 of resistor R18 is grounded to BGND; terminal 2 of resistor R19 is grounded to BGND.

[0044] In practical operation, pin 1 of control chip 21 is the pin of the internal error amplifier, connected to the differential amplifier circuit 4, controlling the signal input to the differential amplifier circuit 4 to adjust the feedback compensation signal output from output pin 6 to the isolation control circuit 3; pin 2 of control chip 21 is the voltage feedback pin, and pin 8 is the reference voltage output pin. Pin 1 of capacitor C12 is electrically connected to pin 8 of control chip 21, and pin 2 of capacitor C12 is electrically connected to pin 2 of control chip 21 to filter the reference voltage. Simultaneously, the reference voltage output from pin 2 of control chip 2 is compared with that output from pin 8 of control chip 2 to generate a control voltage, thereby controlling the pulse width of the feedback compensation signal output from pin 6; control chip 2 Terminal 3 of control chip 21 is the current sampling terminal, electrically connected to resistor R16. Since terminal 2 of resistor R16 is electrically connected to the source (S) of the MOSFET, the current of resistor R16 is sampled and converted into voltage, which is then input to control chip 21 for calculation and control. When the current of MOSFET U11 increases, current sampling can be performed on resistor R16 to control the turn-off of MOSFET U11, effectively protecting MOSFET U11 and preventing it from burning out. Terminal 4 of control chip 21 is the timing terminal, electrically connected to capacitor C17. Capacitor C17 acts as a timing capacitor to adjust the duty cycle of the feedback compensation signal output from terminal 6. Terminal 5 of control chip 21 is ground (GND).

[0045] Furthermore, the differential amplifier circuit 4 includes a second current limiting protection module 41, a fifth current limiting filter module 42, a feedback compensation module 43, an operational amplifier 44, a first output protection module 45, a pull-down module 46, a second switch module 47, and a second output protection module 48. The second current limiting protection module 41 is input to DC. The second current limiting protection module 41 is electrically connected to the fifth current limiting filter module 42, the feedback compensation module 43, and the operational amplifier 44, respectively. The second current limiting protection module 41 is also grounded to BGND. The fifth current limiting filter module 42 is also grounded to BGND. The feedback compensation module 43 is electrically connected to the first output protection module 45. The first output protection module 45 is electrically connected to the pull-down module 46. The pull-down module 46 is electrically connected to the second switch module 47 and is also grounded to BGND. The second switch module 47 is electrically connected to the second output protection module 48 and is also grounded. The second output protection module 48 is electrically connected to the control and adjustment circuit 2. The feedback compensation module 43 is used to improve the output stability of the operational amplifier 44 and suppress output noise; the magnitude of the feedback compensation signal of the control chip 21 is adjusted by turning the second switch module 47 on and off; the functions of the second current limiting protection module 41, the first output protection module 45 and the second output protection module 48 are the same as those of the first current limiting protection module 41; the functions of the fifth current limiting filter module 42 and the fourth current limiting filter module are the same, and will not be described again here.

[0046] It should be noted that the second current limiting protection module 41 includes resistors R24 and R25, with R24 and R25 having terminals 1 and 2 respectively; the fifth current limiting filter module 42 includes resistor R27 and capacitor C33, with R27 and C33 having terminals 1 and 2 respectively; the feedback compensation module 43 includes capacitor C32 and resistor R23, with C32 and R23 having terminals 1 and 2 respectively; the operational amplifier 44 has terminals 1-3; the first output protection module 45 includes resistor R26, with R26 having terminals 1 and 2; the pull-down module 46 includes resistor R28, with R28 having terminals 1 and 2; the second switching module 47 includes a BJT transistor, with the BJT having a base (B), collector (C), and emitter (E); and the second output protection module 48 includes resistor R29, with R29 having terminals 1 and 2. Specifically, terminal 1 of resistor R24 ​​is grounded (BGND), and terminal 2 of resistor R24 ​​is electrically connected to terminal 2 of operational amplifier 44; terminal 1 of resistor R25 is connected to the input voltage DC, and terminal 2 of resistor R25 is electrically connected to terminal 1 of operational amplifier 44, as well as terminal 1 of resistor R27 and capacitor C33; terminals 1 and 2 of resistor R27 and capacitor C33 are connected in parallel, with terminal 2 grounded; terminals 1 and 2 of capacitor C32 and resistor R23 are connected in parallel, and terminal 1 is also connected to operational amplifier 44. Terminal 2 of resistor 4 is electrically connected, and terminal 2 is also electrically connected to terminal 1 of operational amplifier 44; terminal 1 of operational amplifier 44 is electrically connected to terminal 1 of resistor R26; terminal 2 of resistor R26 is electrically connected to terminal 1 of resistor R28 and the base B of transistor BJT respectively; terminal 2 of resistor R28 is grounded to BGND; the collector C of transistor BJT is electrically connected to terminal 1 of resistor R29, and the emitter E of transistor BJT is grounded to BGND; terminal 1 of resistor R29 is electrically connected to control and adjustment circuit 2.

[0047] In summary, in practical implementation, the current direction of power supply 11 in power supply circuit 1 flows from terminal 1 to terminal 2 of diode U12, and finally supplies power to terminals 1 to 2 of winding N1, as well as control chip 21. The current in winding N1 increases, and control chip 21 controls MOSFET U11 to conduct. Since terminal 3 of winding N2 is positive and terminal 4 is negative, diode U17 is not conducting at this time.

[0048] When control chip 21 turns off MOSFET U11, the current in winding N1 reverses direction, and the induced current in winding N2 also reverses direction. This allows a DC voltage to be output from terminals 1 to 2 of diode U17. This DC voltage is then input to terminal 1 of operational amplifier 44 in differential amplifier circuit 4. Since terminal 2 of operational amplifier 44 is grounded, the amplified voltage signal is output from terminal 1 of operational amplifier 44 to the base B of transistor BJT. Because the emitter E of transistor BJT is grounded, the voltage level at base B is greater than that at emitter E, causing transistor BJT to conduct. This signal is then input to terminal 1 of control chip 21. Control chip 21 internally calculates a feedback compensation signal and outputs it from terminal 6 to winding N1 to compensate for the current in winding N1. This, in turn, controls the output voltage V+ at terminal 5 of winding N3 and the input voltage V- at terminal 8 of winding N4. In actual operation, terminal 5 of winding N3 and terminal 8 of winding N4 are connected to the electrical equipment to form a circuit and provide power to the connected electrical equipment.

[0049] The above is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims of the present invention.

Claims

1. A feedback-regulated output isolation circuit, characterized in that, include: The circuit includes a power supply circuit (1), a control and adjustment circuit (2), an isolation output circuit (3), and a differential amplifier circuit (4). The power supply circuit (1) is electrically connected to the control and adjustment circuit (2) and the isolation output circuit (3). The control and adjustment circuit (2) is electrically connected to the isolation output circuit (3) and the differential amplifier circuit (4). The isolation output circuit (3) includes a transformer T1 (31). The transformer T1 (31) has windings N1, N2, N3 and N4. The winding N1 is electrically connected to the power supply circuit (1). The windings N2, N3 and N4 output electrical energy to the outside.

2. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The isolated output circuit (3) further includes a first freewheeling protection module (32) and a first current limiting filter module (33). The winding N2 is electrically connected to the first freewheeling protection module (32). After the first freewheeling protection module (32) is electrically connected to the first current limiting filter module (33), it outputs DC voltage to the outside.

3. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The isolated output circuit (3) further includes a second freewheeling protection module (34), a third freewheeling protection module (35), a first filter module (36), and a second filter module (37). The winding N3 is electrically connected to the second freewheeling protection module (34), and the second freewheeling protection module (34) outputs a voltage V+ after being electrically connected to the first filter module (36). The winding N4 is electrically connected to the third freewheeling protection module (35), and the third freewheeling protection module (35) outputs a voltage V- after being electrically connected to the second filter module (37). The first filter module (36) is also electrically connected to the second filter module (37).

4. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The power supply circuit (1) includes a power supply (11), a fourth freewheeling protection module (12), a second current limiting filter module (13), a third filter module (14), a third current limiting filter module (15), and a fifth freewheeling protection module (16). The power supply (11) is electrically connected to the fourth freewheeling protection module (12). The fourth freewheeling protection module (12) is electrically connected to the second current limiting filter module (13) and the third current limiting filter module (15), respectively. The second current limiting filter module (13) is electrically connected to the third filter module (14) and the control and adjustment circuit (2), respectively. The third filter module (15) is electrically connected to the control and adjustment circuit (2). The third current limiting filter module (15) is electrically connected to the fifth freewheeling protection module (16) and the winding N1, respectively. The fifth freewheeling protection module (16) is electrically connected to the control and adjustment circuit (2).

5. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The control and adjustment circuit (2) includes a control chip (21) and a first switch module (22). The control chip (21) has terminals 1 to 8. The first switch module (22) is electrically connected to terminal 6 of the control chip (21), the power supply circuit (1), and the isolation output circuit (3), respectively. The differential amplifier circuit (4) is electrically connected to terminal 1 of the control chip (21), and the power supply circuit (1) is electrically connected to terminal 7 of the control chip (21).

6. The feedback-regulated output isolation circuit according to claim 5, characterized in that, The control and adjustment circuit (2) further includes a fourth filter module (23), which is electrically connected to terminals 1, 2, 4 and 8 of the control chip (21), and is also electrically connected to the first switch module (22). The fourth filter module (23) is also grounded to GND.

7. The feedback-regulated output isolation circuit according to claim 5, characterized in that, The control and adjustment circuit (2) further includes a fourth current limiting filter module (24), which is electrically connected to the 3rd terminal of the control chip (21) and the first switch module (22) respectively. The fourth current limiting filter module (24) is also grounded to GND.

8. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The control and adjustment circuit (2) further includes an oscillation module (25), which is electrically connected to terminal 8 of the control chip (21).

9. The feedback-regulated output isolation circuit according to claim 1, characterized in that, The control and regulation circuit (2) further includes a first current limiting protection module (26), which is electrically connected to terminal 6 of the control chip (21) and the first switch module (22), and the first current limiting protection module (26) is also grounded to GND.

10. A feedback-regulated output isolation circuit according to claim 1, characterized in that, The differential amplifier circuit (4) includes a second current limiting protection module (41), a fifth current limiting filter module (42), a feedback compensation module (43), an operational amplifier (44), a first output protection module (45), a pull-down module (46), a second switch module (47), and a second output protection module (48). The second current limiting protection module (41) is input to a DC voltage. The second current limiting protection module (41) is electrically connected to the fifth current limiting filter module (42), the feedback compensation module (43), and the operational amplifier (44). The second current limiting protection module (41) is also grounded. BGND; the fifth current limiting filter module (42) is also grounded to BGND; the feedback compensation module (43) is electrically connected to the first output protection module (45), and the first output protection module (45) is electrically connected to the pull-down module (46); the pull-down module (46) is electrically connected to the second switch module (47), and the pull-down module (46) is also grounded to BGND; the second switch module (47) is electrically connected to the second output protection module (48), and the second switch module (47) is also grounded; the second output protection module (48) is electrically connected to the control and adjustment circuit (2).

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