Flyback switching power supply and high frequency converter

Abstract

The application relates to a flyback switching power supply and a high-frequency converter, which comprises a rectification filter, a high-frequency converter, a width-modulated square wave rectifier and a control circuit. The high-frequency converter comprises a GaN power switch tube and a high-frequency planar transformer. An input end of the rectification filter is used for being connected to an alternating voltage, an input end of the GaN power switch tube is electrically connected to an output end of the rectification filter, an output end of the GaN power switch tube is electrically connected to an input end of the high-frequency planar transformer, a control end of the GaN power switch tube is electrically connected to an output end of the control circuit, and an output end of the high-frequency planar transformer is electrically connected to an input end of the width-modulated square wave rectifier. An output end of the width-modulated square wave rectifier is used for outputting a direct-current voltage, an input end of the control circuit is electrically connected to the output end of the width-modulated square wave rectifier, and the control circuit is used for controlling the turn-on and turn-off of the GaN power switch tube. The power supply volume is greatly reduced, and the power supply efficiency is higher.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic circuits, and relates to a flyback switching power supply and a high-frequency converter. BACKGROUND

[0002] In contemporary electronic technology, power supplies play a vital role in electronic products. With the increasing demand for high power density in the market, the power density of power supplies is also required to be increased. With the development of power supply technology, the development and innovation of silicon power supply technology have greatly reduced the size of power supply products, but it is difficult to make further breakthroughs. Under the existing size specifications, silicon materials cannot output higher power at the required frequency. For many years, silicon has been a basic material in electronic components, widely used in alternating current and direct current conversion, and adjusting direct current voltage to meet the technical needs of many applications from mobile phones to industrial robots. Although necessary components have been continuously improved and optimized, the physical limit is the biggest challenge to continue to improve the application of silicon materials.

[0003] In recent years, in the field of power supplies, GaN (gallium nitride) has gradually become one of the key words and has been applied in some power supply products. However, in the process of implementing the present application, the inventor found that the traditional flyback switching power supply is still designed using MOS tube technology, which has the technical problem of large power supply volume. SUMMARY

[0004] In view of the problems existing in the above-mentioned traditional method, the present application provides a flyback switching power supply which can greatly reduce the volume of the flyback switching power supply and has higher power supply efficiency, and provides a high-frequency converter.

[0005] In order to achieve the above-mentioned purpose, the embodiments of the present application adopt the following technical solutions:

[0006] On the one hand, a flyback switching power supply is provided, which comprises a rectifier filter, a high-frequency converter, a width-modulated square wave rectifier and a control circuit; the high-frequency converter comprises a GaN power switch tube and a high-frequency planar transformer;

[0007] The input end of the rectifier filter is used to access an alternating voltage, the input end of the GaN power switch tube is electrically connected to the output end of the rectifier filter, the output end of the GaN power switch tube is electrically connected to the input end of the high-frequency planar transformer, the control end of the GaN power switch tube is electrically connected to the output end of the control circuit, and the output end of the high-frequency planar transformer is electrically connected to the input end of the width-modulated square wave rectifier.

[0008] The output end of the width-modulated square wave rectifier is used to output a direct current voltage, the input end of the control circuit is electrically connected to the output end of the width-modulated square wave rectifier, and the control circuit is used to control the turn-on and turn-off of the GaN power switch tube.

[0009] In one of the embodiments, the high-frequency planar transformer comprises a planar high-frequency core and a winding, the planar high-frequency core comprises an E-type ferrite core, an RM-type ferrite core or a ring-type ferrite core, and the winding is a multi-layer printed circuit board interleaved winding structure.

[0010] In one of the embodiments, the control circuit is a PWM control circuit.

[0011] In one of the embodiments, the PWM control circuit comprises a sampler, a comparator, a pulse width modulator, an oscillator and a reference voltage module.

[0012] The sampler, the comparator and the pulse width modulator are electrically connected in sequence, the input end of the sampler is electrically connected to the output end of the width-adjusted square wave rectifier, and the output end of the pulse width modulator is electrically connected to the control end of the GaN power switch tube.

[0013] The control end of the pulse width modulator is electrically connected to the oscillator, and the reference input end of the comparator is electrically connected to the reference voltage module.

[0014] On the other hand, a high-frequency transformer is also provided, comprising a GaN power switch tube and a high-frequency planar transformer.

[0015] The input end of the GaN power switch tube is electrically connected to the output end of the rectifier filter, the output end of the GaN power switch tube is electrically connected to the input end of the high-frequency planar transformer, the control end of the GaN power switch tube is electrically connected to the PWM control circuit, and the output end of the high-frequency planar transformer is electrically connected to the input end of the width-adjusted square wave rectifier.

[0016] In one of the embodiments, the high-frequency planar transformer comprises a planar high-frequency core and a winding, the planar high-frequency core comprises an E-type ferrite core, an RM-type ferrite core or a ring-type ferrite core, and the winding is a multi-layer printed circuit board interleaved winding structure.

[0017] One of the above technical solutions has the following advantages and beneficial effects:

[0018] The above flyback switching power supply and high-frequency converter, by adopting GaN power switch tube and small size planar transformer to form the high-frequency converter of the flyback switching power supply, since the GaN power switch tube has smaller power consumption and higher efficiency than the traditional MOS power switch tube, the device volume of the GaN power switch tube is far smaller than that of the traditional MOS power switch tube under the condition of outputting the same power, and higher power density is supported, so that the volume of the high-frequency converter can be effectively reduced. Moreover, the rear device of the GaN power switch tube adopts the high-frequency planar transformer, that is, the latest planarization technology is adopted for design, so that the volume of the high-frequency converter is greatly reduced and radio frequency interference can be suppressed. Compared with the traditional flyback switching power supply, the flyback switching power supply adopting GaN and planar transformer technology has greatly reduced volume and higher power efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0020] Figure 1 The structure schematic diagram of the flyback switching power supply in one embodiment;

[0021] Figure 2 The structure schematic diagram of the flyback switching power supply in another embodiment. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the specification of the present application is only for the purpose of describing specific embodiments and is not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0024] It can be understood that "electrical connection" in the following embodiments means corresponding direct or indirect "circuit connection" or "communication connection" if the connected circuits, modules and the like have electrical signal or data transmission between each other.

[0025] In practical research, new power supply and conversion systems based on GaN have emerged, which can generate less power consumption and heat dissipation problems. Since high temperature increases operating costs, interferes with network signals and causes equipment to fail prematurely, the related characteristics of the power supply become more important.

[0026] Research has found that GaN can provide higher frequency and efficiency in flyback switching power supply applications, and can output the same power in only half the space and power consumption of silicon materials. In this way, GaN technology not only improves the power density of flyback switching power supply, but also meets higher power requirements without increasing design space.

[0027] Supporting higher switching frequency means that GaN can convert a larger range of power at a time, thereby reducing power conversion in complex devices. Since each power conversion generates new power consumption, this is a key advantage for growing high-voltage applications. Therefore, instead of using traditional MOS tube technology in flyback switching power supply, the present application uses GaN technology and higher efficiency front-end and back-end modules, so that the GaN-based flyback switching power supply can greatly reduce the size of the power supply and improve the power density of the power supply compared to the traditional MOS tube technology flyback switching power supply.

[0028] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0029] Please refer to Figure 1 The embodiment of the present application provides a flyback switching power supply 100, which includes a rectifier filter 12, a high-frequency converter 14, a width-modulated square wave rectifier 16 and a control circuit 18. The high-frequency converter 14 includes a GaN power switch tube 142 and a high-frequency planar transformer 144. The input end of the rectifier filter 12 is used to access the alternating voltage. The input end of the GaN power switch tube 142 is electrically connected to the output end of the rectifier filter 12, the output end of the GaN power switch tube 142 is electrically connected to the input end of the high-frequency planar transformer 144, and the control end of the GaN power switch tube 142 is electrically connected to the output end of the control circuit 18. The output end of the high-frequency planar transformer 144 is electrically connected to the input end of the width-modulated square wave rectifier 16. The output end of the width-modulated square wave rectifier 16 is used to output a direct current voltage, and the input end of the control circuit 18 is electrically connected to the output end of the width-modulated square wave rectifier 16. The control circuit 18 is used to control the turn-on and turn-off of the GaN power switch tube 142.

[0030] It can be understood that the specific circuit connection mode between the devices in the overall circuit architecture of the flyback switching power supply 100 can be understood by analogy with the circuit connection mode of the circuit architecture of the conventional flyback switching power supply. The rectifier filter 12 is used to convert the alternating current input into a direct current voltage output. The high-frequency converter 14 is used to convert the direct current voltage output by the rectifier filter 12 into a high-frequency voltage. The width-modulated square wave rectifier 16 is used to modulate and filter the direct current voltage output by the high-frequency converter 14, so that the final output direct current voltage is more stable and reliable. The control circuit 18 is used to sample the output direct current voltage and drive and control the high-frequency converter 14 (control the turn-on and turn-off of the GaN power switch tube 142) according to the output direct current voltage.

[0031] Since the driving control of the GaN power switch tube 142 is more complex than the conventional MOS tube, the driving voltage is lower, only 6V, and therefore the required driving capability is higher, so the control circuit 18 can use various control chip devices in the art that can provide the required driving capability. The high-frequency planar transformer 144 is a high-frequency transformer designed using the latest planar technology, rather than a three-dimensional transformer made by traditional skeleton winding method, so the volume of the high-frequency converter 14 can be greatly reduced, thereby ensuring that the overall volume of the flyback switching power supply 100 can be greatly miniaturized.

[0032] The flyback switching power supply 100 described above, by using the GaN power switch tube 142 and the small-size planar transformer high-frequency planar transformer 144 to constitute the high-frequency converter 14 of the flyback switching power supply 100, since the GaN power switch tube 142 has lower power consumption and higher efficiency than the conventional MOS power switch tube, and the device volume of the GaN power switch tube 142 is much smaller than that of the conventional MOS power switch tube under the same power output, supporting higher power density, so the volume of the high-frequency converter 14 can be effectively reduced. Moreover, the GaN power switch tube 142 uses a high-frequency planar transformer 144, i.e. uses the latest planar technology design, which ensures that the volume of the high-frequency converter 14 is greatly reduced and radio frequency interference can be suppressed. Compared with the conventional flyback switching power supply, the flyback switching power supply 100 described above using GaN and planar transformer technology has a greatly reduced power supply volume and higher power supply efficiency.

[0033] In one embodiment, the high-frequency planar transformer 144 includes a planar high-frequency core and a winding. The planar high-frequency core includes an E-type ferrite core, an RM-type ferrite core, or a ring-type ferrite core, and the winding is a multi-layer printed circuit board winding structure.

[0034] It can be understood that the high-frequency planar transformer 144 adopts a small-size E-type, RM-type or ring-type ferrite core, which is usually made of high-frequency power ferrite material and has low core loss at high frequency; and the winding of the high-frequency planar transformer 144 is formed by laminating a plurality of printed circuit boards, and the winding or copper sheet is laminated on the planar high-frequency core to form a magnetic circuit of the transformer. Such design has low DC copper resistance, low leakage inductance and distributed capacitance, which can well meet the design requirements of the resonant circuit. Moreover, due to the good magnetic shielding of the magnetic core, radio frequency interference can also be suppressed, thereby further improving the performance of the power supply.

[0035] In one embodiment, the control circuit 18 is a PWM control circuit. Alternatively, the control circuit 18 can adopt various types of PWM (pulse width modulation) control circuits (chips) known in the art as long as they can be used to provide the driving control function required by the GaN power switch tube 142; the PWM control circuit is usually a chip device, which has a higher degree of miniaturization, so the volume of the flyback switching power supply 100 can be further reduced and the power supply efficiency can be improved.

[0036] Referring to Figure 2 In one embodiment, the PWM control circuit includes a sampler 181, a comparator 183, a pulse width modulator 185, an oscillator 187 and a reference voltage module 189. The sampler 181, the comparator 183 and the pulse width modulator 185 are electrically connected in sequence. The input end of the sampler 181 is electrically connected to the output end of the width-modulated square wave rectifier 16, and the output end of the pulse width modulator 185 is electrically connected to the control end of the GaN power switch tube 142. The control end of the pulse width modulator 185 is electrically connected to the oscillator 187, and the reference input end of the comparator 183 is electrically connected to the reference voltage module 189.

[0037] It can be understood that in the present embodiment, a certain existing PWM control chip is adopted, and the circuit can be divided into the above-mentioned parts according to the functions realized, wherein the sampler 181 is used to sample the output DC voltage from the output end of the width-modulated square wave rectifier 16, then send the sampled voltage signal into the comparator 183 for comparison with the reference voltage provided by the reference voltage module 189, and then send the comparison result into the pulse width modulator 185, which controls the GaN power switch tube 142 under the clock excitation provided by the oscillator 187 according to the comparison result, so as to realize the required flyback modulation function, so that the DC voltage output by the width-modulated square wave rectifier 16 is always the required optimum voltage.

[0038] Referring to Figure 2In one embodiment, a high frequency converter 14 is provided, which includes a GaN power switch tube 142 and a high frequency planar transformer 144. An input end of the GaN power switch tube 142 is electrically connected to an output end of the rectifier filter 12. An output end of the GaN power switch tube 142 is electrically connected to an input end of the high frequency planar transformer 144. A control end of the GaN power switch tube 142 is electrically connected to a PWM control circuit. An output end of the high frequency planar transformer 144 is electrically connected to an input end of the width-modulated square wave rectifier 16.

[0039] It can be understood that the specific explanation and limitation of the high frequency converter 14 can be understood in the same way as the corresponding explanation and limitation of the flyback switching power supply 100 described above, which will not be repeated here. The PWM control circuit can be any type of PWM (pulse width modulation) control chip available in the art, as long as it can be used to provide the required driving control function of the GaN power switch tube 142. The PWM control circuit is usually a chip device, which has a high degree of miniaturization. Therefore, the high frequency converter 14 with the above structure and the PWM control circuit used to provide the driving control required by the GaN power switch tube 142 can significantly reduce the size of the flyback switching power supply 100 and improve the power efficiency.

[0040] The high frequency converter 14 described above uses a GaN power switch tube 142 and a small size planar transformer, i.e. the high frequency planar transformer 144, to form the high frequency converter 14 of the flyback switching power supply 100. Since the GaN power switch tube 142 has lower power consumption and higher efficiency than the traditional MOS power switch tube, the device size of the GaN power switch tube 142 is much smaller than that of the traditional MOS power switch tube when outputting the same power, which supports higher power density, so the size of the high frequency converter 14 can be effectively reduced. Moreover, the GaN power switch tube 142 uses a high frequency planar transformer 144, i.e. uses the latest planar technology design, which ensures that the size of the high frequency converter 14 is greatly reduced and the radio frequency interference can be suppressed. Compared with the traditional flyback switching power supply, the high frequency converter 14 described above using GaN and planar transformer technology, combined with the PWM control circuit, makes the size of the flyback switching power supply 100 be greatly reduced and the power efficiency be higher.

[0041] In one embodiment, the high frequency planar transformer 144 includes a planar high frequency core and a winding. The planar high frequency core includes an E-type ferrite core, an RM-type ferrite core or a ring-type ferrite core. The winding is a multi-layer printed circuit board winding structure.

[0042] It can be understood that the high-frequency planar transformer 144 can adopt a small-size E-type, RM-type or ring-type ferrite core, which is usually made of high-frequency power ferrite material and has low core loss at high frequency; and the winding of the high-frequency planar transformer 144 is formed by laminating a plurality of printed circuit boards, and the winding or copper sheet is laminated on the planar high-frequency core to form a magnetic circuit of the transformer. Such a design has low DC copper resistance, low leakage inductance and distributed capacitance, and can well meet the design requirements of the resonant circuit. Moreover, due to the good magnetic shielding of the core, radio frequency interference can also be suppressed, thereby further improving the performance of the power supply.

[0043] The technical features of the above embodiments can be combined in any manner. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0044] The above embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for those skilled in the art, some modifications and improvements can be made without departing from the concept of the present application, and all of them belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A flyback switching power supply, characterized by comprising: Including rectifier filter, high frequency converter, width modulation square wave rectifier and control circuit;The high frequency converter includes GaN power switch tube and high frequency planar transformer, and the high frequency planar transformer is a high frequency transformer designed by planarization technology; The input end of the rectifier filter is used for accessing alternating voltage, the input end of the GaN power switch tube is electrically connected with the output end of the rectifier filter, the output end of the GaN power switch tube is electrically connected with the input end of the high frequency planar transformer, the control end of the GaN power switch tube is electrically connected with the output end of the control circuit, and the output end of the high frequency planar transformer is electrically connected with the input end of the width modulation square wave rectifier; The output end of the width modulation square wave rectifier is used for outputting direct current voltage, the input end of the control circuit is electrically connected with the output end of the width modulation square wave rectifier, and the control circuit is used for controlling the turn-on and turn-off of the GaN power switch tube. The high frequency planar transformer includes a planar high frequency core and a winding, the planar high frequency core includes an E-shaped ferrite core, an RM-shaped ferrite core or a ring-shaped ferrite core, and the winding is a multi-layer printed circuit board interleaved winding structure.

2. The flyback switching power supply according to claim 1, characterized in that The control circuit is a PWM control circuit.

3. The flyback switching power supply according to claim 2, characterized in that The PWM control circuit includes a sampler, a comparator, a pulse width modulator, an oscillator and a reference voltage module; The sampler, the comparator and the pulse width modulator are electrically connected in sequence, the input end of the sampler is electrically connected with the output end of the width modulation square wave rectifier, and the output end of the pulse width modulator is electrically connected with the control end of the GaN power switch tube. The control end of the pulse width modulator is electrically connected with the oscillator, and the reference input end of the comparator is electrically connected with the reference voltage module.

4. A high frequency transformer, characterized by Including GaN power switch tube and high frequency planar transformer, and the high frequency planar transformer is a high frequency transformer designed by planarization technology; The input end of the GaN power switch tube is electrically connected with the output end of the rectifier filter, the output end of the GaN power switch tube is electrically connected with the input end of the high frequency planar transformer, the control end of the GaN power switch tube is electrically connected with the PWM control circuit, and the output end of the high frequency planar transformer is electrically connected with the input end of the width modulation square wave rectifier; The high frequency planar transformer includes a planar high frequency core and a winding, the planar high frequency core includes an E-shaped ferrite core, an RM-shaped ferrite core or a ring-shaped ferrite core, and the winding is a multi-layer printed circuit board interleaved winding structure.

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