Isolated power supply system and wireless modulation device and method for PFM control

Abstract

The invention provides an isolated power supply system and a wireless modulation device and method for PFM control, and is applied to the technical field of PFM and isolated power supplies, in the isolated power supply system based on PFM, on the basis that a power transformer can transmit a power signal, a low-frequency PFM signal used for power modulation is used as a switching signal, and the switching signal is used as a switching signal. According to the PFM modulation method, a primary side power inductor is used for generating a high-frequency signal, a part of the secondary side power inductor is used for forming resonance, the high-frequency signal is generated after resonance to realize PFM modulation and transmitted through an isolated gate, and finally, the signal can be restored by using a corresponding decoding circuit of a primary side to complete modulation transmission of the PFM signal. Power and signal transmission is achieved through the same power transformer, an additional digital transformer / isolation capacitor is not needed, an additional bias module, an oscillator and the like are not needed, the circuit structure is simplified, and the cost and the chip area are effectively reduced.

Description

Technical Field

[0001] This application relates to the technical fields of PFM modulation and isolated power supply, and particularly relates to an isolated power supply system, a wireless modulation device and method for PFM control. Background Art

[0002] In an isolated power supply / wireless charging system, power is transmitted through a transformer. PFM (Pulse Frequency Modulation) control is a common load modulation scheme, that is, power regulation is achieved by changing the driving frequency of the power stage. The principle is that the secondary side transmits a low-frequency PFM signal with a fixed duty cycle and variable frequency. After being decoded by the primary side, it is frequency-multiplied and used to drive the power stage. Since there is voltage isolation between the primary and secondary sides, additional feedback channels are often required for modulation signals, such as digital transformers or isolation capacitors. At the same time, the relatively low-frequency PFM signal (about 500 kHz) cannot be directly transmitted to the transmitting chip through a digital transformer / capacitor. An additional module is responsible for encoding and decoding the feedback signal at both ends of the on-chip transformer / capacitor to achieve the transmission of PFM signals with different frequencies to adjust the average input power and ensure the stability of the output voltage. Therefore, the transmission of PFM signals not only requires complex encoding and decoding circuits to ensure the reliability of the signal channel, but also requires additional on-chip digital transformers or isolation capacitors as isolation channels, greatly increasing the cost and design complexity of the chip. Summary of the Invention

[0003] In view of this, this application provides an isolated power supply system, a wireless modulation device and method for PFM control, which can complete signal transmission based on a power inductor, eliminating the need for additional isolation channels, simplifying the design and reducing costs.

[0004] This application provides the following technical solutions:

[0005] This application provides a wireless modulation device for PFM control, including:

[0006] A power transformer: a transformer composed of a primary coil and a secondary coil, serving as an isolation medium for power and signal isolation transmission; wherein, the primary coil includes a primary power transmission port and a primary signal transmission port, the secondary coil includes a secondary power transmission port and a secondary signal transmission port, the primary signal transmission port is a two-terminal port formed by taking a part of the inductance in the primary coil and leading it out, the secondary signal transmission port is a two-terminal port formed by taking a part of the inductance in the secondary coil and leading it out, the power signal realizes power transmission from the primary coil to the secondary coil through the primary power transmission port to the secondary power transmission port, and the PFM signal realizes feedback signal transmission from the secondary coil to the primary coil through the secondary signal transmission port to the primary signal transmission port;

[0007] Resonant circuit: It includes a PFM control signal input port, two resonant ports, and a resonant loop; among them, the two resonant ports are connected to the secondary side signal transmission port; the PFM control signal input port is used to input a PFM signal; the resonant loop is used to form a new resonant unit with a part of the inductance taken from the secondary coil in the secondary side signal transmission port, so as to resonate a preset high-frequency signal under the control of the PFM signal, and realize the wireless modulation transmission of the PFM signal from the secondary coil side to the primary coil side, where the connection between the two resonant ports of the resonant loop and the secondary side signal transmission port is controlled by the PFM signal: when the PFM signal is valid, the connection between the two resonant ports of the resonant loop and the secondary side signal transmission port is connected, and when the PFM signal is invalid, the connection between the two resonant ports of the resonant loop and the secondary side signal transmission port is cut off.

[0008] Preferably, the resonant loop includes a capacitor and a switch; among them, the control end of the switch serves as the control signal input port, one end of the capacitor and one end of the switch respectively serve as the two resonant ports, the other end of the capacitor and the other end of the switch are connected, and when the PFM signal is valid, the capacitor and a part of the inductance taken from the secondary coil in the secondary side signal transmission port form the new resonant unit of parallel resonance.

[0009] Preferably, the capacitor is an on-chip capacitor.

[0010] Preferably, the switch is a transistor switch.

[0011] Preferably, the transistor switch is a MOS transistor.

[0012] Preferably, the capacitor and the switch are integrally designed on the same chip.

[0013] Preferably, the frequency of the high-frequency signal resonated by the new resonant unit is different from the frequency of the power signal and the ringing signal frequency generated by the power signal, where the frequency of the high-frequency signal is:

[0014]

[0015] where L is the inductance value of a part of the inductance taken from the secondary coil in the secondary side signal transmission port, and C is the capacitance value of the capacitor.

[0016] Preferably, for the wireless modulation device for PFM control described in any one of the present applications, the wireless modulation device for PFM control is used to replace the isolation gate in the isolation power supply system based on PFM control.

[0017] The present application also provides a wireless modulation method for PFM control, including:

[0018] Input the PFM signal into the PFM control signal input port, where the PFM control signal input port is the PFM control signal input port provided in the wireless modulation device for PFM control as described in any one of the present applications;

[0019] Based on the power transformer, realize the power transmission of the power signal from the primary coil to the secondary coil, and based on the resonant circuit and a part of the inductance taken from the secondary coil in the secondary side signal transmission port, resonate the PFM signal to a preset high-frequency signal, and realize the feedback signal transmission of the high-frequency signal from the secondary coil to the primary coil; among them, the power transformer and the resonant circuit are the power transformer and the resonant circuit provided in the wireless modulation for PFM control as described in any one of the present applications.

[0020] Preferably, the frequency of the resonated high-frequency signal is determined by the following method: determined according to the inductance value of a part of the inductance taken from the secondary coil in the secondary side signal transmission port and / or the capacitance value of the capacitor in the resonant circuit, where the frequency of the high-frequency signal is:

[0021]

[0022] where L is the inductance value of a part of the inductance taken from the secondary coil in the secondary side signal transmission port, and C is the capacitance value of the capacitor.

[0023] The present application also provides an isolated power supply system based on PFM control, including an inverter circuit, a rectifier circuit, an isolation gate, a PFM encoding circuit, and a PFM decoding circuit. The isolation gate includes a power transformer provided in the wireless modulation device for PFM control as described in any one of the present applications; the PFM encoding circuit includes a feedback circuit and a resonant circuit, where the resonant circuit includes a resonant circuit provided in the wireless modulation device for PFM control as described in any one of the present applications;

[0024] Among them, the primary side power transmission port of the power transformer is electrically connected to the inverter circuit, the secondary side power transmission port is connected to the rectifier circuit, the primary side signal transmission port is electrically connected to the PFM decoding circuit, the secondary side signal transmission port is connected to the resonant circuit, and the PFM control signal input port of the resonant circuit is electrically connected to the feedback circuit;

[0025] The feedback circuit is used to sample the output voltage of the rectifier circuit and generate a low-frequency PFM control signal with a corresponding frequency; the PFM decoding circuit is used to recover the low-frequency PFM signal from the high-frequency signal output from the primary side signal transmission port; the inverter circuit is used to convert the input DC voltage into an AC power signal according to the PFM signal output by the PFM decoding circuit; the power transformer is used for power signal and high-frequency signal transmission; the rectifier circuit is used to convert the power signal from the power transformer into a DC output voltage.

[0026] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above technical solutions adopted in this application at least include:

[0027] Compared with the traditional method for implementing digital signal transmission, the present invention constitutes a PFM signal modulation isolation transmission through a power transformer and a resonant circuit, and has the following advantages:

[0028] (1) Signal transmission is carried out through a power transformer, without the need for an additional digital isolation gate, greatly reducing the cost and area.

[0029] (2) The coding circuit is simple, only requiring a switching tube and a resonant capacitor, without a bias circuit, an oscillator circuit, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] Figure 1 is a functional block diagram of a traditional isolated power supply system;

[0032] Figure 2 is a schematic structural diagram of a wireless transmission implementation of an isolated power supply system based on PFM control in this application;

[0033] Figure 3 is a schematic diagram of waveforms at key nodes of wireless signal transmission in this application;

[0034] Figure 4 is a schematic diagram of a resonant structure composed of a capacitor and a switch for wireless transmission implementation of an isolated power supply system based on PFM control in this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The embodiments of this application will be described in detail below in conjunction with the drawings.

[0036] The following describes the implementation manners of the present application through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0037] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present application, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects described herein can be used to implement the device and / or practice the method. In addition, this device and / or this method can be implemented using other structures and / or functions in addition to one or more of the aspects described herein.

[0038] It should also be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner. The drawings only show the components related to the present application, rather than being drawn according to the number, shape and size of the components in actual implementation. The type, quantity and proportion of each component in actual implementation can be an arbitrary change, and the component layout type may also be more complex.

[0039] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the examples can be practiced without these specific details.

[0040] As Figure 1 shown, in the existing isolated power supply system, it usually includes main components such as a transmitting chip, an isolation chip and a receiving chip. Among them, the transmitting chip usually includes an inverter and a controller, and according to the control of the controller, the input DC power supply V DDIt is inverted into an AC power signal, and the isolation chip is driven by the AC power signal, so as to transfer the power energy to the receiving chip side; the isolation chip mainly includes a power transformer and a digital isolation capacitor, which respectively serve as the isolation barriers of the system to realize AC power transmission and control signal feedback transmission; the receiving chip usually includes an inverter and a feedback circuit, which are used to rectify the received AC power signal into a stable DC output voltage V ISO , and a feedback signal is formed according to the actual output and transmitted to the transmitting chip through the digital isolation capacitor of the isolation chip.

[0041] It should be noted that in the feedback signal transmission channel, the high-voltage digital isolation capacitor composed of SiO 2 provides an insulation barrier between different voltage domains and provides a high-frequency signal transmission path. At present, the commonly used feedback digital channel scheme is the OOK on-off keying modulation scheme. Its principle is that the transmitter (TX) modulates the input signal to the carrier frequency, that is, the TX transmits a high-frequency signal through the isolation capacitor in one input state, and no signal passes through the isolation capacitor in another input state, so as to realize encoding (i.e., modulation) transmission; then, the receiver (RX) reconstructs the TX transmitted signal according to the detected in-band data.

[0042] Therefore, the signal transmission in the scheme highly depends on an additional isolation capacitor. That is, in the isolated power supply system, an additional isolation channel needs to be added for load modulation, which not only increases the cost but also is not conducive to the miniaturization and integration design of the chip.

[0043] In view of this, through in-depth research and improvement exploration of the isolated power supply system and its modulation method, it is found that:

[0044] On the one hand, the transformer can realize energy transmission isolation between the primary side and the secondary side, so the power transformer is a common component in the isolated power supply system. Therefore, if the power transformer can be used to transmit the feedback signal on the secondary side to the primary side, the isolated transmission of the feedback signal should no longer require a digital isolation capacitor.

[0045] On the other hand, in the isolated power supply system based on PFM (pulse frequency modulation) control, during the process of transmitting power energy by the power transformer, there is always energy on the secondary side power inductor L S . Therefore, if a small amount of power energy can be used to realize the feedback signal transmission when the feedback signal is transmitted from the secondary side to the primary side based on the power transformer, the isolated transmission of the feedback signal should no longer require an additional bias circuit.

[0046] As Figure 2 shown, the present invention proposes an isolated power supply system and a wireless modulation transmission scheme for PFM control:

[0047] On the one hand, the isolation chip in the isolated power supply system (which can also be called isolator, isolation circuit, isolation gate, etc., without distinction) is improved to an isolation gate form that only contains a power transformer 200 for power transmission, and the power transformer 200 is improved to the following new structural form, that is, the power transformer 200 includes: a primary power transmission port V PP 、V PN , which is used to connect the inverter circuit 100 on the transmitting chip side; a secondary power transmission port V SP 、V SN , which is used to connect the rectifier circuit 300 on the receiving chip side; and a primary signal transmission port V PA 、V PB and a secondary signal transmission port V SA 、V SB , which are respectively used to connect the decoding circuit 600 and the encoding circuit (see the improved content in the following example).

[0048] After the power transformer 200 is improved to a new isolation structure, since the power transformer 200 can not only realize the transmission of power energy from the primary side to the secondary side, but also realize the transmission of the PFM feedback signal from the secondary side to the primary side, the digital isolation capacitor required for the transmission of the feedback signal can no longer be set in the isolation chip, which can simplify the design of the isolation gate and save the circuit area.

[0049] On the other hand, for the need of PFM signal transmission, the PFM encoding circuit is improved to obtain a new encoding circuit, which can include: a resonant circuit 500 and a feedback circuit 400, where the resonant circuit 500 forms a new resonant unit with the power transformer 200, that is, in the isolated power supply system based on PFM control, a part of the inductance is taken out from the secondary power inductor Ls, and a new resonant frequency higher than the PFM frequency can be resonated with the newly added resonant circuit 500, so as to realize the transmission of the PFM feedback signal (that is, the feedback circuit 400 generates a low-frequency PFM signal according to the output voltage) from the secondary side to the primary side.

[0050] Among them, the low-frequency PFM signal used for power feedback modulation is used to connect or disconnect the secondary signal transmission ports V SA 、V SB of the resonant circuit 500 connected to the secondary power inductor Ls. Thus, when the resonant circuit 500 is connected, the resonant circuit 500 and a part of the inductance taken out from the secondary power inductor Ls form a new resonant unit, generating a high-frequency signal with a frequency higher than the PFM signal. Therefore, the PFM feedback signal in the form of this high-frequency signal can reach the primary side through the isolation gate and is restored by the decoding circuit 600 connected to the primary signal transmission ports V PA 、V PB .

[0051] In summary, the improved technical solution does not require an additional digital transformer / isolation capacitor, nor an additional bias module, oscillator, etc. It only needs to form corresponding signal transmission ports on the primary and secondary sides of the power transformer respectively, and use a small part of the inductance in the secondary inductance Ls and the newly added resonant circuit to reconstitute a new resonant unit. The principle is simple and the circuit structure is simplified.

[0052] It should be noted that although the wireless modulation scheme example of the PFM signal in this application takes the PFM signal in the isolated power supply system as an example, other systems facing PFM control and requiring isolated transmission of the PFM signal can also use the device of this application to achieve. That is, the isolated power supply system is an application example of the wireless modulation scheme of the PFM signal in this application, and other similar application scenarios can refer to the application method of the PFM signal in the isolated power supply system.

[0053] The following describes the technical solutions provided by the embodiments of this application with reference to the accompanying drawings.

[0054] The core idea of the present invention is: using the power transformer in the isolated power supply system as the signal transmission path, without adding an additional digital isolation transformer / capacitor, greatly reducing the chip area and packaging cost.

[0055] Reference Figure 2 As shown, the present invention proposes an isolated power supply system which mainly includes: an inverter circuit 100, a power transformer 200, a rectifier circuit 300, a feedback circuit 400, a resonant circuit 500, and a decoding circuit 600. It should be noted that the inverter circuit 100 and the rectifier circuit 300 can be the relevant circuits in the original scheme or newly designed circuits, which are not limited here.

[0056] The following combines Figure 3 the waveforms shown to illustrate the composition and functions of each circuit:

[0057] Inverter circuit 100: used to invert the input DC voltage V DD into a differential high-frequency oscillating power signal V PP and V PN , and output from the V PP and V PN ports to the primary coil L P of the micro-transformer 200;

[0058] Power transformer 200: composed of a primary coil L P and a secondary coil L S , serving as an isolation medium and realizing power transmission from the primary to the secondary, and signal transmission from the secondary to the primary;

[0059] Rectifier circuit 300: used to rectify the secondary terminal V SPand V SN Rectify the received high-frequency oscillation signal into a DC signal and provide it to the output load;

[0060] Feedback circuit 400: Used to sample the output voltage and generate low-frequency PFM signals with different frequencies to achieve a constant output voltage;

[0061] Resonant circuit 500: Used to convert the low-frequency PFM signal into a high-frequency oscillation signal V SA 、V SB ;

[0062] Decoding circuit 600: Used to decode the high-frequency oscillation signals V PA 、V PB Decode and restore them to low-frequency PFM signals, and feedback them back to the inverter circuit 100.

[0063] The transformer 200 includes: a primary power transmission port V PP 、V PN for connecting to the inverter circuit 100, a secondary power transmission port V SP 、V SN for connecting to the rectifier circuit 300, and also includes a primary signal transmission port V PA 、V PB for connecting to the decoding circuit 600 and a secondary signal transmission port V SA 、V SB for connecting to the encoding circuit, where the encoding circuit can be the circuit form composed of the aforementioned resonant circuit 500 and feedback circuit 400 to achieve the modulation of the PFM signal (i.e., achieve encoding).

[0064] Where V PA 、V PB are ports formed by taking out a part of the inductance of the primary coil, V SP 、V SN are ports formed by taking out a part of the inductance of the secondary coil, and the two parts of the inductance are mutually coupled.

[0065] Combined with Figure 2 and Figure 3 The schematic content, the working schematic of the overall circuit is as follows: The power signal passes through the primary power transmission ports V PP 、V PN and the secondary power transmission ports V SP 、V SN to achieve power transmission; After the PFM signal resonates into a high-frequency signal with a higher frequency, it passes through the secondary signal transmission ports V SA 、V SB and the primary signal transmission ports V PA 、V PB to achieve signal transmission, and then the decoding circuit on the primary side passes through VPA and V PB to decode the high-frequency oscillation signal on it to complete the feedback transmission of the PFM signal.

[0066] In addition, since the inductance between V SA and V SB is only a part of the secondary-side inductance, and the resonance frequency needs to be distinguished from the power-stage drive frequency and the chip ringing frequency, and the capacitance value of the on-chip resonance capacitor is very limited. Therefore, its oscillation amplitude is negligible compared to the voltage between the power inductors V SP and V SN and does not affect the power transmission of the power stage, nor will it increase the output ripple.

[0067] From Figure 3 the waveform diagram of the key nodes of the signal transmission shown, it can be seen that: PFM_S is the low-frequency signal output by the secondary-side feedback control module. When PFM_S is high, the resonance circuit works, and V SP -V SN transmits high-frequency signals to the primary side, and the output PFM_P of the decoding circuit is translated to high, and the primary-side power stage alternately works to transmit power; when PFM_S is low, the resonance circuit is turned off, and the output PFM_P of the decoding circuit is translated to low, and the primary-side power stage is turned off.

[0068] In some examples, the preferred implementation of the resonance circuit 500 can refer to Figure 4 the schematic circuit shown, that is, the resonance circuit 500 can be simplified to the following circuit structure: only including a resonance capacitor C1 and a switch S1.

[0069] Referring to Figure 4 shown, the PFM signal is used as the control signal of S1, and is connected to / disconnected from the LC loop in an on / off manner to achieve signal encoding. Its main principle is that during the process of the power stage transmitting power, there is energy on the secondary-side power inductor L S . When the PFM signal is high, that is, the switch is closed, the resonance capacitor C1 will perform LC resonance with the inductance between V SA and V SB , without an additional power supply and oscillation circuit, and its resonance frequency is:

[0070]

[0071] The frequency of this signal depends on the inductance between V SA and V SB and the resonance capacitor C1.

[0072] In summary, in an isolated power supply system based on PFM modulation, a low-frequency PFM signal for power modulation is used as a switching signal, and a part of the secondary power inductor is taken to form an LC series resonance. The generated high-frequency signal can pass through the isolation gate, and the corresponding decoding circuit on the primary side can restore the signal to complete signal transmission. This solution does not require additional digital transformers / isolation capacitors, nor additional bias modules, oscillators, etc. It only requires a resonant capacitor and a switching transistor, and the principle is simple.

[0073] In some preferred examples, the capacitor in the resonant circuit is set as an on-chip capacitor.

[0074] In some preferred examples, the switch is preferably an electronic switch composed of a transistor, such as a preferred MOS transistor. Specifically, a PMOS transistor or an NMOS transistor can be preferably selected according to the circuit design.

[0075] In some preferred examples, the capacitor and the switch can be integrally designed on the same chip, thus forming a chip of the resonant circuit. When different resonant frequencies are required, the corresponding chip can be selected to resonate with the inductor of the power transformer.

[0076] In some preferred examples, according to the requirement of setting the resonant frequency, the power transformer is provided with secondary signal transmission ports with different inductance values on the secondary side, or secondary signal transmission ports with corresponding inductance values are provided on different power transformers, so as to flexibly adapt to the matching requirements of different resonant frequencies.

[0077] Based on the same inventive concept, the present application also provides a wireless modulation method for PFM control.

[0078] Referring to the foregoing various device examples, a wireless modulation method for PFM control may include:

[0079] Step 1: Input the PFM signal into the PFM control signal input port, and the PFM control signal input port is the PFM control signal input port provided in the wireless modulation device for PFM control described in any one of the present application.

[0080] It should be noted that the PFM signal can be a type of low-frequency signal that needs to be isolated and transmitted, such as the PFM signal used for feedback control in an isolated power supply system, whose frequency is about 500 kHz. In isolated transmission, it often needs to be modulated into a signal with a higher frequency and then isolated and transmitted through an isolation capacitor. After using the wireless modulation solution of the present application, the low-frequency PFM signal can be used as the switching signal of the resonant circuit, so that under the switching control, a part of the inductor of the power transformer resonates with the resonant circuit.

[0081] Step 2: Implement power transfer of the power signal from the primary coil to the secondary coil based on a power transformer, and resonate the PFM signal to a preset high-frequency signal based on a resonant circuit and a part of the inductance taken from the secondary coil in the secondary signal transmission port, and implement feedback signal transmission of the high-frequency signal from the secondary coil to the primary coil; wherein, the power transformer and the resonant circuit are the power transformer and the resonant circuit provided in any one of the wireless modulations for PFM control in the present application.

[0082] It should be noted that while transferring power through the power transformer, the modulation and transmission of the PFM signal are realized. For the specific working principle, reference can be made to the content of the foregoing examples, and no further elaboration will be made here.

[0083] In some embodiments, the modulation is achieved through resonance, and the resonance can be realized by an LC resonant circuit composed of a resonant capacitor in the resonant circuit and a part of the inductance in the secondary side of the power transformer. Therefore, in the wireless modulation of the PFM signal, the frequency of the modulation signal can be determined by the capacitance and / or inductance value. Thus, the frequency of the high-frequency signal obtained by resonance can be determined by setting the inductance value of a part of the inductance taken from the secondary coil in the secondary signal transmission port and / or the capacitance value of the capacitor in the resonant circuit. In other words, in practical applications, by replacing different inductance values and capacitance values, the usage requirements for the modulation frequency in different scenarios can be met. Regarding the resonant frequency, reference can be made to the foregoing examples, and no further elaboration will be made here.

[0084] In this specification, for the same or similar parts among the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and for the relevant parts, reference can be made to the partial description of the foregoing embodiments.

[0085] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A wireless modulation device for PFM control, characterized in that: include: Power transformer: A transformer consisting of a primary coil and a secondary coil, which serves as an isolation medium for power and signal isolation transmission; wherein the primary coil includes a primary power transmission port and a primary signal transmission port, and the secondary coil includes a secondary power transmission port and a secondary signal transmission port. The primary signal transmission port is a two-terminal port formed by a part of the inductance in the primary coil, and the secondary signal transmission port is a two-terminal port formed by a part of the inductance in the secondary coil. The power signal is transmitted from the primary coil to the secondary coil through the primary power transmission port to the secondary power transmission port, and the PFM signal is transmitted from the secondary coil to the primary coil through the secondary signal transmission port to the primary signal transmission port. Resonant circuit: comprising a PFM control signal input port, two resonant ports and a resonant loop; wherein the two resonant ports are connected to a secondary signal transmission port; the PFM control signal input port is used to input a PFM signal; the resonant loop is used to form a new resonant unit with a part of the inductance taken from the secondary coil in the secondary signal transmission port, so as to resonate a preset high-frequency signal under the control of the PFM signal, and realize the wireless modulation transmission of the PFM signal from one side of the secondary coil to the side of the primary coil, wherein the connection between the two resonant ports of the resonant loop and the secondary signal transmission port is controlled by the PFM signal: when the PFM signal is valid, the connection between the two resonant ports of the resonant loop and the secondary signal transmission port is connected, and when the PFM signal is invalid, the connection between the two resonant ports of the resonant loop and the secondary signal transmission port is cut off.

2. The wireless modulation device for PFM control according to claim 1, characterized in that: The resonant circuit includes a capacitor and a switch; wherein the control end of the switch serves as the control signal input port, one end of the capacitor and one end of the switch serve as the two resonant ports respectively, and the other end of the capacitor is connected to the other end of the switch. When the PFM signal is valid, the capacitor and a part of the inductance taken from the secondary coil in the secondary side signal transmission port form the new resonant unit of parallel resonance.

3. The wireless modulation device for PFM control according to claim 2, characterized in that: The capacitor is an on-chip capacitor; And / or, the switch is a transistor switch.

4. The wireless modulation device for PFM control according to claim 3, characterized in that: The transistor switch is a MOS tube.

5. The wireless modulation device for PFM control according to claim 2, characterized in that: The capacitor and the switch are integrated and designed on the same chip.

6. The wireless modulation device for PFM control according to claim 2, characterized in that: The frequency of the high-frequency signal obtained by the resonance of the new resonance unit is different from the frequency of the power signal and the frequency of the ringing signal generated by the power signal, wherein the frequency of the high-frequency signal is: Wherein, L is the inductance value of a portion of the inductance in the secondary coil in the secondary signal transmission port, and C is the capacitance value of the capacitor.

7. The wireless modulation device for PFM control according to any one of claims 1 to 6, characterized in that: The wireless modulation device for PFM control is used to replace the isolation barrier in the isolated power supply system based on PFM control.

8. A wireless modulation method for PFM control, characterized in that: include: Inputting the PFM signal to a PFM control signal input port, wherein the PFM control signal input port is a PFM control signal input port provided in the wireless modulation device for PFM control according to any one of claims 1 to 7; Power transmission of the power signal from the primary coil to the secondary coil is realized based on a power transformer, and the PFM signal is resonated to a preset high-frequency signal based on a resonant circuit and a part of the inductance taken from the secondary coil in the secondary signal transmission port, and the high-frequency signal is transmitted from the secondary coil to the primary coil to realize feedback signal transmission; wherein the power transformer and the resonant circuit are the power transformer and the resonant circuit provided in the wireless modulation for PFM control as described in any one of claims 1-7.

9. The wireless modulation method for PFM control according to claim 8, characterized in that: The frequency of the high-frequency signal obtained by resonance is determined in the following manner: according to the inductance value of a portion of the inductance in the secondary coil and / or the capacitance value in the resonant circuit in the secondary signal transmission port, wherein the frequency of the high-frequency signal is: Wherein, L is the inductance value of a portion of the inductance in the secondary coil in the secondary signal transmission port, and C is the capacitance value of the capacitor.

10. An isolated power supply system based on PFM control, comprising an inverter circuit, a rectifier circuit, an isolation barrier, a PFM encoding circuit and a PFM decoding circuit, characterized in that: The isolation barrier includes a power transformer provided by the wireless modulation device for PFM control as claimed in any one of claims 1 to 7; the PFM encoding circuit includes a feedback circuit and a resonant circuit, wherein the resonant circuit includes a resonant circuit provided by the wireless modulation device for PFM control as claimed in any one of claims 1 to 7; The primary power transmission port of the power transformer is electrically connected to the inverter circuit, the secondary power transmission port is electrically connected to the rectifier circuit, the primary signal transmission port is electrically connected to the PFM decoding circuit, the secondary signal transmission port is connected to the resonant circuit, and the PFM control signal input port of the resonant circuit is electrically connected to the feedback circuit; The feedback circuit is used to sample the output voltage of the rectifier circuit and generate a low-frequency PFM control signal of the corresponding frequency; the PFM decoding circuit is used to restore the low-frequency PFM signal from the high-frequency signal output from the primary signal transmission port; the inverter circuit is used to convert the input DC voltage into an AC power signal according to the PFM signal output by the PFM decoding circuit; the power transformer is used for power signal and high-frequency signal transmission; the rectifier circuit is used to convert the power signal from the power transformer into a DC output voltage.

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