Isolated dc-dc power supply and electronic device

Abstract

This disclosure provides an isolated DC-DC power supply and electronic device. The DC-DC power supply includes: a cross-coupled circuit, a primary coil, etc.; the cross-coupled circuit and the primary coil form an LC resonant circuit; the cross-coupled circuit includes two cross-coupled power switching transistors and capacitor array circuits corresponding to the power switching transistors one-to-one, the first terminal of each capacitor array circuit is electrically connected to the drain of the corresponding power switching transistor, and the second terminal of each capacitor array circuit is grounded; each capacitor array circuit includes several parallel capacitor branches, and each capacitor branch includes a branch switch and a branch capacitor connected in series. This disclosure controls the resonant frequency to fluctuate within a wider range by randomly selecting capacitors of different sizes in the capacitor array circuit, which can disperse the radiation spectrum originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases with the change of frequency, thereby reducing electromagnetic radiation interference.

Description

Technical Field

[0001] This disclosure relates to the field of electronic circuit technology, and in particular to an isolated DC-DC power supply and electronic device. Background Technology

[0002] In traditional isolated DC-DC power supplies, the cross-coupled circuit and the primary coil together form an LC (inductor-capacitor) resonant circuit. The main drawback of this type of DC-DC power supply is that the conventional PWM (pulse width modulation) control mode for the LC resonant circuit results in a large number of high-order harmonic components in the high-frequency switching waveform generated by the high-frequency switching waveform generated by the cross-coupled circuit as the switching frequency of the power transistor in the cross-coupled circuit increases, which will generate serious electromagnetic interference (EMI). Summary of the Invention

[0003] The technical problem to be solved by this disclosure is to address the aforementioned deficiencies in the prior art, and to provide an isolated DC-DC power supply and electronic device.

[0004] This disclosure solves the above-mentioned technical problems through the following technical solution:

[0005] This disclosure provides an isolated DC-DC power supply, which includes: a cross-coupled circuit, a primary coil, a secondary coil, and a rectifier and filter circuit;

[0006] The cross-coupling circuit and the primary coil form an LC resonant circuit. The first end of the cross-coupling circuit is electrically connected to the first end of the primary coil, and the second end of the cross-coupling circuit is electrically connected to the second end of the primary coil.

[0007] The primary coil sends a signal to the secondary coil through induction. The secondary coil converts the signal into a current signal and transmits the current signal to the rectifier and filter circuit. The rectifier and filter circuit generates a DC voltage based on the current signal.

[0008] The cross-coupled circuit includes two cross-coupled power switches and a capacitor array circuit that corresponds to each power switch. The first terminal of each capacitor array circuit is electrically connected to the drain of the corresponding power switch, and the second terminal of each capacitor array circuit is grounded.

[0009] Each of the capacitor array circuits includes several parallel capacitor branches, and each capacitor branch includes a branch switch and a branch capacitor connected in series.

[0010] Optionally, by controlling the switching state of the branch switches in the capacitor array circuit, the resonant frequency of the LC resonant circuit can be dispersed to a preset frequency band;

[0011] Between the two capacitor array circuits, the switching states of the corresponding branch switches remain consistent.

[0012] Optionally, the switching state of the branch switches in the capacitor array circuit can be controlled by a randomly generated random code.

[0013] Optionally, for each of the capacitor array circuits, the capacitance value of each branch capacitor is an integer multiple of the unit capacitance value, and the capacitance values ​​of each branch capacitor are different from one another.

[0014] Optionally, for each of the capacitor array circuits, the branch capacitance with the minimum capacitance value is one unit capacitance value, and the branch capacitance increases incrementally in increments of one unit capacitance value.

[0015] Optionally, all branch switches are NMOS (N-channel metal-oxide-semiconductor) transistors;

[0016] In each of the capacitor branches, the drain of the branch switch is electrically connected to one end of the branch capacitor, the source of the branch switch is grounded, and the gate of the branch switch receives a switch control signal to control the switch state.

[0017] Optionally, the cross-coupling circuit further includes a main capacitor;

[0018] The power switching transistor includes a first power switching transistor and a second power switching transistor;

[0019] The drain of the first power switch is also electrically connected to the first terminal of the main capacitor and the gate of the second power switch.

[0020] The drain of the second power switch is also electrically connected to the second terminal of the main capacitor and the gate of the first power switch.

[0021] The source of both the first power switch and the source of the second power switch are grounded;

[0022] The drain of the first power switch is used as the first terminal of the cross-coupling circuit, and the drain of the second power switch is used as the second terminal of the cross-coupling circuit.

[0023] Optionally, both the first power switch and the second power switch are NMOS transistors.

[0024] Optionally, the DC-DC power supply further includes: an error amplifier, a PWM controller, and a drive circuit;

[0025] The error amplifier is used to detect fluctuations in the DC voltage generated by the rectifier filter circuit and transmit the fluctuations to the PWM controller;

[0026] The PWM controller is used to generate a drive control signal based on the fluctuation, and transmit the drive control signal to the drive circuit;

[0027] The driving circuit is used to control the duty cycle of the oscillation pulse according to the driving control signal, and output the oscillation pulse to the gate of the two power switching transistors to start the oscillation of the LC resonant circuit.

[0028] This disclosure also provides an electronic device comprising the above-described isolated DC-DC power supply.

[0029] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of this disclosure.

[0030] The positive and progressive effects of this disclosure are as follows: by setting up a capacitor array circuit in the cross-coupled circuit that corresponds one-to-one with the power switch, and by randomly selecting capacitors of different sizes in the capacitor array circuit, the resonant frequency of the LC resonant circuit can be controlled to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an isolated DC-DC power supply provided in Embodiment 1 of this disclosure;

[0032] Figure 2 This is a schematic diagram of the structure of an isolated DC-DC power supply LC resonant circuit provided in Embodiment 1 of this disclosure;

[0033] Figure 3 A schematic diagram of a capacitor array circuit example in an LC resonant circuit diagram of an isolated DC-DC power supply provided in Embodiment 1 of this disclosure;

[0034] Figure 4 A schematic diagram of the structure of an LC resonant circuit in an isolated DC-DC power supply provided in Embodiment 1 of this disclosure;

[0035] Figure 5 Control waveform diagram of 16 switches of an isolated DC-DC power supply provided in Embodiment 1 of this disclosure;

[0036] Figure 6 A comparison diagram of the spectrum signals of an LC resonant circuit for an example of a 16-switch isolated DC-DC power supply provided in Embodiment 1 of this disclosure. Detailed Implementation

[0037] The present disclosure is further illustrated below by way of embodiments, but the present disclosure is not limited to the scope of the embodiments described herein.

[0038] The prefixes such as "first" and "second" used in this disclosure are merely for distinguishing different descriptive objects and do not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes used to distinguish descriptive objects in this disclosure does not constitute a limitation on the described objects. The description of the described objects is given in the claims or the context of the embodiments, and should not be construed as an unnecessary limitation. Furthermore, in the description of this embodiment, unless otherwise stated, "multiple" means two or more.

[0039] Example 1

[0040] Figure 1 This is a schematic diagram of an isolated DC-DC power supply provided as an exemplary embodiment of the present disclosure. The isolated DC-DC power supply includes: a cross-coupled circuit 1, a primary coil L1, a secondary coil L2, and a rectifier and filter circuit 2. The primary coil L1 and the secondary coil L2 form a transformer isolator, VDD represents the power supply voltage, and the arrows indicate the signal flow direction.

[0041] The cross-coupled circuit 1 and the primary coil L1 form an LC resonant circuit. The first end of the cross-coupled circuit 1 is electrically connected to the first end of the primary coil L1, and the second end of the cross-coupled circuit 1 is electrically connected to the second end of the primary coil L1.

[0042] The primary coil L1 sends a signal to the secondary coil L2 through induction. The secondary coil L2 converts the signal into a current signal and transmits the current signal to the rectifier and filter circuit 2. The rectifier and filter circuit 2 generates a DC voltage based on the current signal.

[0043] Reference Figure 2 The cross-coupled circuit 1 includes two cross-coupled power switching transistors (MM1 and MM2) and a capacitor array circuit CAP that corresponds to each power switching transistor. The first terminal of each capacitor array circuit CAP is electrically connected to the drain of the corresponding power switching transistor, and the second terminal of each capacitor array circuit CAP is grounded. Figure 2 In the middle, two Cs gg These are the inherent equivalent parasitic capacitances of power switching transistors MM1 and MM2, respectively. Power switching transistors MM1 and MM2 are the same device, and M is the mutual inductance between the primary coil L1 and the secondary coil L2.

[0044] Reference Figure 3Each capacitor array circuit (CAP) includes several parallel capacitor branches, and each capacitor branch includes a branch switch (example: M1-M16) and a branch capacitor (example: C1-C16) connected in series. Figure 3 In the example, the number of branch switches and branch capacitors is set to 16, but other numbers can be set according to the actual situation.

[0045] Among them, the overall structure of the traditional isolated DC-DC power supply in the existing technology is also like... Figure 1 As shown, Figure 4 A schematic diagram of the LC resonant circuit diagram of an isolated DC-DC power supply in the prior art is shown. Figure 4 In the middle, two Cs gg These are the inherent equivalent parasitic capacitances of the power switching transistors MM1 and MM2. In the prior art, the primary coil L1 and the secondary coil L2 form a transformer isolator. A signal is transmitted to the secondary coil L2, which receives the signal and converts it into a current signal. The rectifier and filter circuit 2 generates a stable DC voltage based on the current signal. The error amplifier 3 feeds back the fluctuation of the DC voltage to the PWM controller 4. The PWM controller 4 then generates a drive control signal to control the drive circuit 5 to generate an oscillation pulse, which is used to start the oscillation of the LC resonant circuit. The main drawback of the prior art is that the conventional PWM control mode, as the switching frequency of the power transistors increases, produces a large number of high-order harmonic components in the high-frequency switching waveform, which will generate serious electromagnetic interference.

[0046] Compared to existing technologies, the isolated DC-DC power supply in this embodiment sets up a capacitor array circuit in the cross-coupling circuit 1 that corresponds one-to-one with the power switching transistor. By randomly selecting capacitors of different sizes in the capacitor array circuit, the resonant frequency of the LC resonant circuit is controlled to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference.

[0047] Specifically, the cross-coupled circuit 1 can employ random modulation techniques, using shift registers or other methods to generate pseudo-random numbers. Pseudo-random numbers The range is between 0 and 1, and the calculation formula (1) is as follows:

[0048] .

[0049] Where f represents the resonant frequency of the LC resonant circuit, f0 represents the fundamental resonant frequency of the LC resonant circuit, and R i Indicates the degree of randomness. This represents a pseudo-random number, where i represents the index of the capacitor branch. The index of the capacitor branch is also the index of the branch switch and the index of the branch capacitor, ranging from 1 to N, where N is a positive integer. Through continuously changing R... i and This can broaden the operating frequency range of LC resonant circuits and reduce EMI interference.

[0050] Preferably, a random code generated by a digital module can be used. The bits of the random code are used to control the switching state of the branch switches in the capacitor array circuit, and the bits of the random code correspond one-to-one with the branch switches. For example: Figure 3 In the example, there are 16 branch switches (N=16), corresponding to a 16-bit random code.

[0051] By setting the branch switches in the capacitor array circuit with random codes, the capacitors of different sizes in the capacitor array circuit can be randomly selected, thereby controlling the resonant frequency of the LC resonant circuit to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference.

[0052] Therefore, the resonant frequency of the LC resonant circuit can be expressed by the following formula (2):

[0053] .

[0054] Where f represents the resonant frequency of the LC resonant circuit, L1 represents the primary coil, L2 represents the secondary coil, and x i This indicates the switching state of the branch switch in capacitor branch number i (1 indicates on, 0 indicates off), where i represents the branch number, N represents the number of capacitor branches, and C... gg The equivalent parasitic capacitance of the power switch is represented by M, the mutual inductance between the primary coil L1 and the secondary coil L2 is represented by C, and ΔC is represented by the unit capacitance value.

[0055] Here, C1-CN are all set to be integer multiples of the unit capacitance value, and they gradually increase in increments of one unit capacitance value, starting from one unit capacitance value. The increment can also be set according to the actual situation.

[0056] Formula (2) can be rewritten as:

[0057] .

[0058] .

[0059] Where f represents the resonant frequency of the LC resonant circuit, f0 represents the fundamental resonant frequency of the LC resonant circuit, L1 represents the primary coil, L2 represents the secondary coil, and x i This indicates the switching state of the branch switch in capacitor branch number i (1 indicates on, 0 indicates off), where i represents the branch number, N represents the number of capacitor branches, and C... gg The equivalent parasitic capacitance of the power switch is represented by M, the mutual inductance between the primary coil L1 and the secondary coil L2 is represented by C, and ΔC is represented by the unit capacitance value.

[0060] In the default state, half of the switches in C1 to CN (e.g., C1 to C16) are set to the on state and half of the switches are set to the off state. The purpose is to keep the default frequency in an intermediate state so that the frequency can be increased or decreased.

[0061] Taking N=16 as an example, the simulation results of the control waveform are as follows: Figure 5 As shown, the control waveforms of 16 switches within 272µs (microseconds) were captured. It can be seen that the 16 switches are independent of each other and adjust the resonant frequency of the LC circuit by controlling the size of the capacitor.

[0062] Taking N=16 as an example, Figure 6 The diagram shows a comparison of the spectral signals of the LC resonant circuit (green) of this embodiment with those of the prior art (red). Simulation results are compared between the LC resonant circuit with electromagnetic interference reduction (EMI) circuitry (green) and the LC resonant circuit without EMI reduction (red). A Fast Fourier Transform (FFT) is performed on the output of the LC resonant circuit. It is evident that the signal (green) from the LC resonant circuit with EMI reduction has significantly lower harmonic amplitude and corresponding lower harmonic energy. Furthermore, its individual harmonic bands are broadened, and the peak values ​​are reduced. With a fundamental frequency of 80MHz, the fundamental frequency signal is reduced by 8dB, and the single 80MHz signal is broadened to the range of 79MHz to 86MHz, thus achieving the goal of reducing electromagnetic interference.

[0063] In this embodiment, a capacitor array circuit corresponding to each power switch is set in the cross-coupled circuit. By randomly selecting capacitors of different sizes in the capacitor array circuit, the resonant frequency of the LC resonant circuit is controlled to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference.

[0064] In an optional embodiment, the resonant frequency of the LC resonant circuit is dispersed to a preset frequency band by controlling the switching state of the branch switches in the capacitor array circuit CAP.

[0065] Between the two capacitor array circuits (CAP), the switching states of the corresponding branch switches remain consistent.

[0066] In this circuit, the switching states of the two capacitor array circuits (CAP) are kept consistent, ensuring that the frequencies on both sides of the LC resonant circuit remain the same. This consistency in frequency guarantees a 180-degree phase difference. If the switching states of the two capacitor array circuits (CAP) are not consistent, the frequencies on both sides of the LC resonant circuit will become inconsistent, leading to a larger common-mode voltage deviation.

[0067] In this embodiment, the switching states of the two capacitor array circuits CAP are kept consistent, so that the frequencies on the left and right sides of the LC resonant circuit can be kept consistent. The same frequency ensures a phase difference of 180 degrees, reducing the common-mode voltage deviation.

[0068] In an optional embodiment, the switching state of the branch switches in the capacitor array circuit CAP is controlled by a randomly generated random code.

[0069] In this embodiment, by setting the branch switches in the capacitor array circuit with random codes, the capacitors of different sizes in the capacitor array circuit are randomly selected to control the resonant frequency of the LC resonant circuit to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference.

[0070] In an optional embodiment, for each capacitor array circuit CAP, the capacitance value of each branch capacitor is an integer multiple of the unit capacitance value, and the capacitance values ​​of the branch capacitors are all different from each other.

[0071] In this embodiment, the different capacitance values ​​of the branch capacitors help to match the total capacitance of different capacitor array circuits with different random codes, thereby enabling the electromagnetic radiation spectrum to be evenly distributed across more and wider frequency bands.

[0072] In an optional embodiment, for each capacitor array circuit CAP, the branch capacitance with the minimum capacitance value is one unit capacitance value, and the branch capacitance increases incrementally in increments of one unit capacitance value.

[0073] In this embodiment, the branch capacitor increases gradually in increments of one unit capacitance value, which facilitates manufacturing and control and avoids the branch capacitor having an excessively large capacitance value.

[0074] In an optional embodiment, all branch switches are NMOS transistors.

[0075] In each capacitor branch, the drain of the branch switch is electrically connected to one end of the branch capacitor, the source of the branch switch is grounded, and the gate of the branch switch receives the switch control signal to control the switch state.

[0076] This embodiment provides a specific implementation of a capacitor array circuit.

[0077] In an optional embodiment, the cross-coupled circuit 1 further includes a main capacitor C.

[0078] The power switching transistors include a first power switching transistor MM1 and a second power switching transistor MM2.

[0079] The drain of the first power switch MM1 is also electrically connected to the first terminal of the main capacitor C and the gate of the second power switch MM2.

[0080] The drain of the second power switch MM2 is also electrically connected to the second terminal of the main capacitor C and the gate of the first power switch MM1.

[0081] The source of the first power switch MM1 and the source of the second power switch MM2 are both grounded.

[0082] The drain of the first power switch MM1 is used as the first terminal of the cross-coupled circuit 1, and the drain of the second power switch MM2 is used as the second terminal of the cross-coupled circuit 1.

[0083] This embodiment provides a specific implementation of a cross-coupled circuit.

[0084] In an optional embodiment, both the first power switch MM1 and the second power switch MM2 are NMOS transistors.

[0085] In this embodiment, a specific implementation of a first power switch and a second power switch is provided.

[0086] In an optional embodiment, the DC-DC power supply further includes an error amplifier 3, a PWM controller 4, and a drive circuit 5.

[0087] Error amplifier 3 is used to detect fluctuations in the DC voltage generated by rectifier filter circuit 2 and transmit the fluctuations to PWM controller 4.

[0088] The PWM controller 4 is used to generate drive control signals based on fluctuations and transmit the drive control signals to the drive circuit 5.

[0089] The drive circuit 5 is used to control the duty cycle of the oscillation pulse according to the drive control signal, and output the oscillation pulse to the gate of the two power switching transistors to start the oscillation of the LC resonant circuit.

[0090] in, Figure 2The connection relationship between the drive circuit 5 and the gates of the two power switching transistors is not shown.

[0091] The target value for DC voltage can be 5 volts or other voltage values, and can be set according to the actual situation.

[0092] The target value for DC voltage is 5 volts and Figure 3 Taking the capacitor array circuit shown as an example, when the DC voltage deviates from 5 volts, the PWM controller 4 generates a drive control signal to drive the drive circuit 5 according to the degree of deviation (i.e., fluctuation). This fluctuation affects the duty cycle of the PWM. For example, when the DC voltage becomes 5.1 volts, the duty cycle of the PWM will decrease. The duty cycle of the PWM controls the oscillation time of the LC resonant circuit, because the LC resonant circuit will only start oscillating when the PWM signal (and the start-up pulse) is high, and the LC resonant circuit stops working when the PWM signal is low.

[0093] This embodiment provides a specific implementation of a DC-DC power supply.

[0094] Example 2

[0095] This embodiment provides an electronic device, which includes the isolated DC-DC power supply described in Embodiment 1.

[0096] In this embodiment, a capacitor array circuit corresponding to each power switch is set in the cross-coupled circuit. By randomly selecting capacitors of different sizes in the capacitor array circuit, the resonant frequency of the LC resonant circuit is controlled to fluctuate within a wider range. This can disperse the electromagnetic radiation spectrum that was originally concentrated in the same frequency band to more and wider frequency bands, so that the average value of the noise signal decreases as the resonant frequency changes, thereby reducing electromagnetic radiation interference.

[0097] While specific embodiments of this disclosure have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this disclosure is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this disclosure, but all such changes and modifications fall within the scope of protection of this disclosure.

Claims

1. An isolated DC-DC power supply, characterized in that, The DC-DC power supply includes: a cross-coupled circuit, a primary coil, a secondary coil, and a rectifier and filter circuit; The cross-coupling circuit and the primary coil form an LC resonant circuit. The first end of the cross-coupling circuit is electrically connected to the first end of the primary coil, and the second end of the cross-coupling circuit is electrically connected to the second end of the primary coil. The primary coil sends a signal to the secondary coil through induction. The secondary coil converts the signal into a current signal and transmits the current signal to the rectifier and filter circuit. The rectifier and filter circuit generates a DC voltage based on the current signal. The cross-coupled circuit includes two cross-coupled power switches and a capacitor array circuit that corresponds to each power switch. The first terminal of each capacitor array circuit is electrically connected to the drain of the corresponding power switch, and the second terminal of each capacitor array circuit is grounded. Each of the capacitor array circuits includes several parallel capacitor branches, and each capacitor branch includes a branch switch and a branch capacitor connected in series.

2. The isolated DC-DC power supply as described in claim 1, characterized in that, By controlling the switching state of the branch switches in the capacitor array circuit, the resonant frequency of the LC resonant circuit is dispersed to a preset frequency band. Between the two capacitor array circuits, the switching states of the corresponding branch switches remain consistent.

3. The isolated DC-DC power supply as described in claim 2, characterized in that, The switching state of the branch switches in the capacitor array circuit is controlled by a randomly generated random code.

4. The isolated DC-DC power supply as described in claim 1, characterized in that, For each of the capacitor array circuits, the capacitance value of each branch capacitor is an integer multiple of the unit capacitance value, and the capacitance values ​​of each branch capacitor are different from one another.

5. The isolated DC-DC power supply as described in claim 4, characterized in that, For each of the capacitor array circuits, the branch capacitance with the minimum capacitance value is one unit capacitance value, and the branch capacitance increases incrementally in increments of one unit capacitance value.

6. The isolated DC-DC power supply as described in claim 5, characterized in that, All branch switches are NMOS transistors; In each of the capacitor branches, the drain of the branch switch is electrically connected to one end of the branch capacitor, the source of the branch switch is grounded, and the gate of the branch switch receives a switch control signal to control the switch state.

7. The isolated DC-DC power supply as described in claim 1, characterized in that, The cross-coupling circuit also includes a main capacitor; The power switching transistor includes a first power switching transistor and a second power switching transistor; The drain of the first power switch is also electrically connected to the first terminal of the main capacitor and the gate of the second power switch. The drain of the second power switch is also electrically connected to the second terminal of the main capacitor and the gate of the first power switch. The source of both the first power switch and the source of the second power switch are grounded; The drain of the first power switch is used as the first terminal of the cross-coupling circuit, and the drain of the second power switch is used as the second terminal of the cross-coupling circuit.

8. The isolated DC-DC power supply as described in claim 7, characterized in that, Both the first power switch and the second power switch are NMOS transistors.

9. The isolated DC-DC power supply as described in claim 1, characterized in that, The DC-DC power supply also includes: an error amplifier, a PWM controller, and a drive circuit; The error amplifier is used to detect fluctuations in the DC voltage generated by the rectifier filter circuit and transmit the fluctuations to the PWM controller; The PWM controller is used to generate a drive control signal based on the fluctuation, and transmit the drive control signal to the drive circuit; The driving circuit is used to control the duty cycle of the oscillation pulse according to the driving control signal, and output the oscillation pulse to the gate of the two power switching transistors to start the oscillation of the LC resonant circuit.

10. An electronic device, characterized in that, The electronic device includes an isolated DC-DC power supply as described in any one of claims 1-9.

Images