Isolation power supply circuit

By splitting the input voltage in the voltage conversion module, the number of transformer windings of the DCDC isolating converter is reduced, and the problem of too many turns on the primary winding is solved, achieving a small volume and efficient conversion effect.

CN222884549UActive Publication Date: 2025-05-16SHENZHEN LIHUAHONG ELECTRONIC TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202421830792.0
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-07-30
Publication Date
2025-05-16
Estimated Expiration
2034-07-30

AI Technical Summary

Technical Problem

When designing a DCDC isolation converter with high input voltage, the primary winding turns are too many, the core window is too small, resulting in the winding cannot be lowered, and the output turns are large, making it difficult to achieve small volume and high-efficiency conversion.

Method used

By introducing capacitors C1 and C2 into the voltage conversion module to equalize the input voltage, the volt-second product of the transformer's primary winding is reduced, thereby reducing the number of windings.

Benefits of technology

Effectively reduce the number of windings of the transformer, avoid core saturation, and realize a small-volume and efficient DCDC isolation converter design.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses an isolation power supply circuit, which relates to the field of power electronics, and comprises a voltage conversion module, a voltage output module, an isolation power supply module and an isolation power supply module, wherein the voltage conversion module is used for converting input direct current into alternating current and outputting the alternating current to the voltage output module; voltage equalization is carried out on the input voltage, and after the equalized voltage is obtained, the equalized voltage is input to one end of the input side of the transformer; the beneficial effects of the utility model are that the capacitors C1 and C2 are connected in series to equally divide the input voltage, the voltage at the series connection point is the equally divided voltage and is half of the input voltage, and when the main control chip VPS8701 works normally, the full-bridge structure circuits in the main control chip VPS8701 are switched on in sequence to work, so that the main control chip VPS8701 can work normally. The working loop formed by the primary winding on the transformer TR1 is connected with the series connection point of the series capacitor bank instead of the original connection with the input voltage, at the moment, the volt-second product on the primary winding of the transformer is half of that of a traditional full-bridge circuit, and the winding of the transformer is reduced by half under the corresponding condition.
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Description

Technical Field

[0001] The utility model relates to the field of power electronics, in particular to an isolation power supply circuit. Background Art

[0002] like Figure 1 As shown, in the existing technical solution, the chip VPS8701 is used as the DCDC isolation conversion circuit of the main control IC, which has the advantage of simple peripheral circuits. The main control IC has a full-bridge circuit structure inside, such as Figure 2 When designing this type of DCDC isolation converter, the calculation of the number of turns of the transformer winding is related to parameters such as the operating frequency, the voltage across the winding, and the core side area. Under the same conditions, when the input voltage increases, it is necessary to increase the number of turns to prevent the core from saturating.

[0003] like Figure 2 As shown in the figure, according to the working characteristics of the full-bridge circuit, the switches on the internal bridge arms are switched on alternately, that is, PM1 and NM2 are turned on at the same time, and PM2 and NM1 are turned on at the same time. The traditional application circuit is a typical full-bridge circuit, such as Figure 1 As shown in the figure, when PM1 and NM2 are turned on at the same time or PM2 and NM1 are turned on at the same time, the voltage across the transformer is equal to the voltage at the input end. At this time, the volt-second product of the transformer during the on time increases due to the higher input voltage. Therefore, it is necessary to increase the number of turns of the transformer to prevent its magnetic flux saturation.

[0004] Therefore, when designing a small-volume and high-input-voltage DCDC isolation converter, there will be too many turns in the primary winding, the core window is too small, and it cannot be wound. In the existing technology, a larger core is usually used to solve this problem, but this traditional method will increase costs and make it difficult to reduce the volume. When designing high-voltage output applications, there will also be the problem of a large number of output turns, such as when the output voltage is 24VDC or higher. Since this type of isolation converter achieves voltage conversion through the transformer ratio, when the number of turns of the input primary winding is constant, the higher the output voltage, the more turns it outputs.

[0005] Therefore, the DCDC isolation conversion circuit of the chip VPS8701 as the main control IC has a coil turn limit, which leads to relatively low input and output voltage variations and needs to be improved. Utility Model Content

[0006] The purpose of the utility model is to provide an isolated power supply circuit to solve the problems raised in the above background technology.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] An isolated power supply circuit, comprising:

[0009] The voltage conversion module is used to convert the input direct current into alternating current and output it to the voltage output module; the input voltage is divided equally, and after the divided voltage is obtained, the divided voltage is input to one end of the transformer input side;

[0010] Voltage output module, used to rectify and filter AC power and output it as DC power supply;

[0011] The voltage conversion module is connected to the voltage output module;

[0012] The voltage conversion module includes capacitor C1, capacitor C2, chip U1, and transformer TR1. The model of chip U1 is VPS8701. Pin 5 of chip U1 is connected to one end of capacitor C2 and input voltage VIN. The other end of capacitor C2 is connected to one end of capacitor C1 and the third end of transformer TR1. The other end of capacitor C1 is grounded. Pin 4 or pin 5 of chip U1 is connected to the first end of transformer TR1.

[0013] As a further solution of the utility model: the voltage output module includes a diode D1, a diode D2, a capacitor C3, and a resistor R1, the positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2, one end of the capacitor C3, and one end of the resistor R1, the other end of the capacitor C3 is grounded, and the other end of the resistor R1 is grounded.

[0014] As a further solution of the utility model: the voltage output module includes a diode D1, a diode D2, a capacitor C3, and a capacitor C4, the positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, the negative electrode of the diode D2 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded.

[0015] As a further solution of the utility model: the voltage output module includes a diode D1, a diode D2, and a capacitor C3, the positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2 and one end of the capacitor C3, and the other end of the capacitor C3 is grounded.

[0016] As a further solution of the utility model: the voltage output module includes a diode D1, a diode D2, a capacitor C3, a capacitor C4, and a resistor R1, the anode of the diode D1 is connected to the cathode of the diode D2 and the sixth end of the transformer TR1, one end of the capacitor C3 is connected to one end of the capacitor C4 and the fourth end of the transformer TR1, the anode of the diode D2 is grounded, the other end of the capacitor C4 is grounded, the cathode of the diode D1 is connected to the other end of the capacitor C3 and one end of the resistor R1, and the other end of the resistor R1 is grounded.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: in the present invention, the capacitors C1 and C2 are connected in series to divide the input voltage equally, and the voltage at the series connection point is the divided voltage, which is half of the input voltage. When the main control chip VPS8701 works normally, its internal full-bridge structure circuit is turned on and works in sequence, and the working loop formed by the primary winding on the transformer TR1 is changed from the original connection with the input voltage to the connection with the series connection point of the series capacitor group. At this time, the volt-second product on the primary winding of the transformer is half of that of the traditional full-bridge circuit. Under corresponding conditions, the winding of the transformer is reduced by half. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a circuit diagram of an existing isolated power supply circuit.

[0019] Figure 2 This is the internal structure diagram of the chip VPS8701.

[0020] Figure 3 The figure is a circuit diagram of a first embodiment of an isolated power supply circuit.

[0021] Figure 4 The figure is a circuit diagram of a second embodiment of an isolated power supply circuit.

[0022] Figure 5 The third embodiment is a circuit diagram of an isolated power supply circuit.

[0023] Figure 6 It is a circuit diagram of a fourth embodiment of an isolated power supply circuit.

[0024] Figure 7 The fifth embodiment is a circuit diagram of an isolated power supply circuit. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.

[0026] See also Figures 3 to 6 , an isolated power supply circuit, comprising:

[0027] The voltage conversion module is used to convert the input direct current into alternating current and output it to the voltage output module; the input voltage is divided equally, and after the divided voltage is obtained, the divided voltage is input to one end of the transformer input side;

[0028] Voltage output module, used to rectify and filter AC power and output it as DC power supply;

[0029] The voltage conversion module is connected to the voltage output module;

[0030] The voltage conversion module includes capacitor C1, capacitor C2, chip U1, and transformer TR1. The model of chip U1 is VPS8701. Pin 5 of chip U1 is connected to one end of capacitor C2 and input voltage VIN. The other end of capacitor C2 is connected to one end of capacitor C1 and the third end of transformer TR1. The other end of capacitor C1 is grounded. Pin 4 or pin 5 of chip U1 is connected to the first end of transformer TR1.

[0031] In the specific embodiment: see Figure 1 and Figure 2 According to the working characteristics of the full-bridge circuit, the switch tubes on the internal bridge arms are switched on alternately, that is, MOS tubes PM1 and NM2 are turned on at the same time, and MOS tubes PM2 and NM1 are turned on at the same time. The traditional application circuit is a typical full-bridge circuit. When MOS tubes PM1 and NM2 are turned on at the same time or PM2 and NM1 are turned on at the same time, the voltage across the transformer TR1 is equal to the voltage at the input end. At this time, the volt-second product of the transformer TR1 during the on time increases due to the higher input voltage. Therefore, it is necessary to increase the number of turns of the transformer to prevent its magnetic flux saturation.

[0032] See also Figures 3 to 6 , capacitors C1 and C2 will divide the input voltage VIN by connecting in series. The voltage at the series connection point is the divided voltage VC, which is half of the input voltage VIN. When the main control chip VPS8701 works normally, its internal full-bridge structure circuit is turned on and works in sequence, and the working loop formed by the primary winding on the transformer TR1 is changed from the original connection with the input voltage to the connection with the series connection point of the series capacitor group. At this time, the volt-second product on the primary winding of the transformer is half of that of the traditional full-bridge circuit. Under corresponding conditions, the winding of the transformer is reduced by half.

[0033] In the first embodiment: See Figure 3The voltage output module includes a diode D1, a diode D2, a capacitor C3, and a resistor R1. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2, one end of the capacitor C3, and one end of the resistor R1, the other end of the capacitor C3 is grounded, and the other end of the resistor R1 is grounded.

[0034] The voltage output module is the same as the existing isolated power supply circuit. After the AC voltage is rectified by diodes D1 and D2, it is filtered by capacitor C3 to output stable DC power.

[0035] In the second embodiment: See Figure 4 The voltage output module includes a diode D1, a diode D2, a capacitor C3, and a capacitor C4. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, the negative electrode of the diode D2 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded.

[0036] Output side compared to Figure 3 The single-ended output is changed to a half-wave dual output structure. This output circuit can achieve the effect of dual-channel voltage output. It is also rectified by diodes and filtered by capacitors.

[0037] In the third embodiment: See Figure 5 The voltage output module includes a diode D1, a diode D2, and a capacitor C3. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2 and one end of the capacitor C3, and the other end of the capacitor C3 is grounded.

[0038] Figure 5 and Figure 3 , Figure 4 The biggest difference is that the pins connected to the first end of the chip U1 and the transformer TR1 are different. From the internal circuit block diagram of the main control chip U1, it can be seen that the VD1 pin and the VD2 pin are both internal connection points of the full-bridge circuit. From its working principle, it can be seen that the voltage changes of these two connection points are inverse to each other. Therefore, when using the technical solution of the utility model, the effects of the two connection points are the same.

[0039] In the fourth embodiment: See Figure 6The voltage output module includes a diode D1, a diode D2, a capacitor C3, a capacitor C4, and a resistor R1. The anode of the diode D1 is connected to the cathode of the diode D2 and the sixth end of the transformer TR1. One end of the capacitor C3 is connected to one end of the capacitor C4 and the fourth end of the transformer TR1. The anode of the diode D2 is grounded, the other end of the capacitor C4 is grounded, the cathode of the diode D1 is connected to the other end of the capacitor C3 and one end of the resistor R1, and the other end of the resistor R1 is grounded.

[0040] The output adopts a voltage doubling circuit structure, which only needs one winding to achieve output rectification. In this way, the number of turns on the output side of the transformer in the isolated DCDC converter described in the output can be greatly reduced.

[0041] In the fifth embodiment, see Figure 7 , this application can also be constructed using the chip VPS8703. The internal circuit structure of VPS8703 is similar to that of VPS8701. The two are different in packaging, and the connection method is similar to that of VPS8701.

[0042] The working principle of the utility model is: in the voltage conversion module, capacitors C1 and C2 are connected in series to divide the input voltage VIN, and the voltage at the series connection point is the divided voltage VC, which is half of the input voltage VIN. When the main control chip VPS8701 works normally, its internal full-bridge structure circuit is turned on in sequence, and the working loop formed by the primary winding on the transformer TR1 is changed from the original connection with the input voltage to the connection with the series connection point of the series capacitor group. At this time, the volt-second product on the primary winding of the transformer is half of the traditional full-bridge circuit. Under corresponding conditions, the winding of the transformer is reduced by half, and the voltage output module rectifies and filters the AC power and outputs it as a DC power supply.

[0043] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be considered as exemplary and non-restrictive in all respects.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An isolated power supply circuit, characterized in that: The isolated power supply circuit includes: The voltage conversion module is used to convert the input direct current into alternating current and output it to the voltage output module; the input voltage is divided equally, and after the divided voltage is obtained, the divided voltage is input to one end of the transformer input side; Voltage output module, used to rectify and filter AC power and output it as DC power supply; The voltage conversion module is connected to the voltage output module; The voltage conversion module includes capacitor C1, capacitor C2, chip U1, and transformer TR1. The model of chip U1 is VPS8701. Pin 5 of chip U1 is connected to one end of capacitor C2 and input voltage VIN. The other end of capacitor C2 is connected to one end of capacitor C1 and the third end of transformer TR1. The other end of capacitor C1 is grounded. Pin 4 or pin 5 of chip U1 is connected to the first end of transformer TR1.

2. The isolated power supply circuit according to claim 1, characterized in that: The voltage output module includes a diode D1, a diode D2, a capacitor C3, and a resistor R1. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2, one end of the capacitor C3, and one end of the resistor R1, the other end of the capacitor C3 is grounded, and the other end of the resistor R1 is grounded.

3. The isolated power supply circuit according to claim 1, characterized in that: The voltage output module includes a diode D1, a diode D2, a capacitor C3, and a capacitor C4. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, the negative electrode of the diode D2 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is grounded.

4. The isolated power supply circuit according to claim 1, characterized in that: The voltage output module includes a diode D1, a diode D2, and a capacitor C3. The positive electrode of the diode D1 is connected to the sixth end of the transformer TR1, the positive electrode of the diode D2 is connected to the fourth end of the transformer TR1, the fifth end of the transformer TR1 is grounded, the negative electrode of the diode D1 is connected to the negative electrode of the diode D2 and one end of the capacitor C3, and the other end of the capacitor C3 is grounded.

5. The isolated power supply circuit according to claim 1, characterized in that: The voltage output module includes a diode D1, a diode D2, a capacitor C3, a capacitor C4, and a resistor R1. The anode of the diode D1 is connected to the cathode of the diode D2 and the sixth end of the transformer TR1, one end of the capacitor C3 is connected to one end of the capacitor C4 and the fourth end of the transformer TR1, the anode of the diode D2 is grounded, the other end of the capacitor C4 is grounded, the cathode of the diode D1 is connected to the other end of the capacitor C3 and one end of the resistor R1, and the other end of the resistor R1 is grounded.