Control circuit, power supply circuit, and electronic device for switching power supply

Abstract

The application provides a control circuit of a switching power supply, a power supply circuit and an electronic device. The control circuit outputs a control signal to control the switching frequency of the switching power supply. In multiple periods, the control circuit adjusts the frequency of the control signal according to multiple ranges respectively, and in each period, the frequency of the control signal changes over time in the range corresponding to each period. The application can increase the energy dispersion degree of the control signal output by the control circuit in the frequency domain, reduce the electromagnetic interference generated by the control signal output by the control circuit, and ultimately ensure that the power supply circuit and the electronic device thereof can pass the relevant safety test.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a control circuit, power supply circuit and electronic equipment for a switching power supply. Background Technology

[0002] In existing technologies, power supply circuits typically include a switching power supply and a control circuit. The switching power supply receives the input voltage and provides the output voltage. The control circuit sends control signals to the switching power supply. These control signals control the switching frequency of the switching circuit. If the control signal sent by the control circuit to the switching device is a periodic signal with a fixed period, the energy of the control signal is relatively concentrated in the frequency domain. To reduce the maximum value of the control signal's frequency domain energy so that it passes relevant safety tests, some control circuits send control signals to the switching power supply after processing such as linear spread spectrum. This disperses the energy of the control signal in the frequency domain, and the maximum energy value is also reduced.

[0003] However, using existing technology, the control signals sent by the control circuits to the switching power supply have low energy dispersion in the frequency domain. When the frequency domain energy of the control signal is high, the maximum energy value is still high, which can cause the power supply circuit containing these control circuits to fail relevant safety tests. Summary of the Invention

[0004] This application provides a control circuit, power supply circuit, and electronic device for a switching power supply, which solves the technical problem that the control signal sent by the control circuit to the switching power supply has a low degree of energy dispersion in the frequency domain in the prior art.

[0005] The first aspect of this application provides a control circuit for a switching power supply. The control circuit outputs a control signal to control the switching frequency of the power supply. In multiple cycles, the control circuit adjusts the frequency of the control signal according to multiple ranges, and in each cycle, the frequency of the control signal varies with time within the range corresponding to that cycle. Embodiments of this application increase the energy dispersion of the control signal output by the control circuit in the frequency domain, reduce electromagnetic interference generated by the control signal output by the control circuit, and ultimately ensure that the power supply circuit and the electronic equipment it is located in can pass relevant safety tests.

[0006] In one embodiment of the first aspect of this application, at least one of the duration of at least one of the multiple periods of the control signal and at least one of the amplitudes of at least one range of the multiple ranges is random. When the duration and / or range of the control signal output by the control circuit varies randomly, the uncertainty of the control signal output by the control circuit can be increased, the periodicity of the control signal is further weakened, and the energy dispersion of the control signal in the frequency domain is further improved. Even when the frequency domain energy of the control signal is large, the spectral energy value of the control signal output by the control circuit can be reduced as much as possible.

[0007] In one embodiment of the first aspect of this application, the control circuit is used to adjust the duration of at least one of a plurality of cycles, such that the duration of at least one cycle is greater than or less than the duration of the previous cycle. In this embodiment, since the control signal does not change according to a fixed period, and the duration of the periodic change in the frequency of the control signal is random, the periodicity of the control signal is greatly eliminated. Therefore, the energy of the spectrum at the corresponding discrete frequency points is significantly expanded, thereby further reducing the spectral energy value of the control signal.

[0008] In one embodiment of the first aspect of this application, the control circuit is used to randomly adjust the duration of at least one of a plurality of cycles. This embodiment enables the duration of the periodic changes in the frequency of the control signal to be random, greatly eliminating the periodicity of the control signal and further reducing the spectral energy value of the control signal. Furthermore, the method for determining the cycle duration is relatively simple and direct, allowing the control circuit to generate the control signal more effectively.

[0009] In one embodiment of the first aspect of this application, the control circuit is used to adjust the duration of the at least one period based on a random number corresponding to the at least one period and the duration of a reference period. This embodiment enables the periodic variation duration of the control signal's frequency to be random, greatly eliminating the periodicity of the control signal and further reducing the spectral energy value of the control signal. Furthermore, since the control circuit obtains the period duration based on the reference period and the random number, it can more effectively constrain the variation in the period duration.

[0010] In one embodiment of the first aspect of this application, the control circuit is used to adjust the amplitude of at least one of a plurality of ranges, wherein the amplitude of the at least one range is less than or greater than the amplitude of the preceding range. In this embodiment, the control signal output by the control signal does not change according to a fixed period, and the amplitude of the frequency variation range of the control signal within each period is random, greatly eliminating the periodicity of the control signal. Therefore, the spectrum energy is significantly expanded at the corresponding discrete frequency points. This further reduces the spectral energy value of the control signal.

[0011] In one embodiment of the first aspect of this application, the control circuit is used to: adjust the amplitude of at least one range based on a random number corresponding to at least one period and a reference range. The control circuit is used to: adjust the amplitude of at least one range to be greater than 90% and less than the amplitude of the reference range; or, adjust the amplitude of at least one range to be greater than the amplitude of the reference range and less than 110% of the amplitude of the reference range. In this embodiment, the amplitude of the frequency variation range of the control signal output by the control circuit within each period is random, which can further reduce the spectral energy value of the control signal. Furthermore, since the control circuit obtains the duration of the period based on the reference period and the random number, it can more effectively constrain the variation of the amplitude of the range within the period.

[0012] A second aspect of this application provides a power supply circuit, including a switching power supply and a control circuit. The switching power supply includes at least one switching device. The control circuit outputs a control signal to control the switching frequency of the switching device. The switching frequency of the switching device varies according to multiple ranges in multiple cycles, and the range corresponding to the switching frequency of the switching device in each cycle varies with time. The control circuit provided in this application reduces the energy dispersion of the control signal output in the frequency domain when controlling the switching frequency of the switching device, thereby reducing the electromagnetic interference generated by the control signal output by the control circuit, ultimately ensuring that the power supply circuit and the electronic equipment it is located in can pass relevant safety tests.

[0013] In one embodiment of the second aspect of this application, the control circuit includes a clock source and a modulator. The clock source generates a clock signal, and the modulator modulates the clock signal according to multiple ranges in multiple cycles to generate a control signal. The control circuit provided in this embodiment can generate a clock signal and modulate it to obtain a control signal, thereby enriching the control functionality.

[0014] In one embodiment of the second aspect of this application, at least one of the duration of at least one of the multiple periods of the control signal and at least one of the amplitudes of at least one range of the multiple ranges is random. When the duration and / or range of the control signal output by the control circuit varies randomly, the uncertainty of the control signal output by the control circuit can be increased, the periodicity of the control signal is further weakened, and the energy dispersion of the control signal in the frequency domain is further improved. Even when the frequency domain energy of the control signal is large, the spectral energy value of the control signal output by the control circuit can be reduced as much as possible.

[0015] In one embodiment of the second aspect of this application, in the switching frequency of the switching device, the duration of at least one of the multiple cycles is such that the duration of at least one cycle is greater than or less than the duration of the previous cycle. In this embodiment, since the control signal used to control the switching device does not change according to a fixed period, and the duration of the periodic change in the frequency of the control signal is random, the periodicity of the control signal is greatly eliminated. Therefore, the energy of the spectrum at the corresponding discrete frequency points is significantly expanded. This further reduces the spectral energy value of the control signal.

[0016] In one embodiment of the second aspect of this application, the amplitude of the switching frequency change of the switching device over time in at least one of the multiple cycles is less than or greater than the amplitude of the switching frequency change over time in the previous cycle. In this embodiment, the control signal used to control the switching device does not change according to a fixed period, and the amplitude of the frequency change range of the control signal within each cycle is random, greatly eliminating the periodicity of the control signal. Therefore, the spectrum energy is significantly expanded at the corresponding discrete frequency points, thereby further reducing the spectral energy value of the control signal.

[0017] In one embodiment of the second aspect of this application, the switching power supply includes one of a boost circuit, a buck circuit, or a buck-boost circuit. The embodiments of this application can be applied to switching power supplies with non-isolation functions, enriching the application scenarios of the embodiments of this application.

[0018] In one embodiment of the second aspect of this application, the switching power supply includes either an asymmetric half-bridge flyback converter circuit or an active clamp flyback converter circuit. The embodiments of this application can be applied to switching power supplies with isolation functions, enriching the application scenarios of the embodiments of this application.

[0019] A third aspect of this application provides an electronic device, including a control circuit as provided in any of the first aspects of this application, or a power supply circuit as provided in any of the second aspects of this application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0022] Figure 2A schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0023] Figure 3 A schematic diagram of a power supply circuit provided in an embodiment of this application;

[0024] Figure 4 A schematic diagram of a power supply circuit provided in an embodiment of this application;

[0025] Figure 5 A schematic diagram of a power supply circuit provided in an embodiment of this application;

[0026] Figure 6 This is a waveform diagram of a control signal sent by a control circuit in the prior art.

[0027] Figure 7 This is a waveform diagram of a control signal sent by a control circuit in the prior art.

[0028] Figure 8 A waveform diagram of a control signal sent by a control circuit provided in this application;

[0029] Figure 9 A waveform diagram of a control signal sent by a control circuit provided in this application;

[0030] Figure 10 A waveform diagram of a control signal sent by a control circuit provided in this application;

[0031] Figure 11 A schematic diagram of a control circuit provided in this application;

[0032] Figure 12 A schematic diagram of a scenario for conducting conductivity tests on the power supply circuit provided in this application. Detailed Implementation

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] The connection relationships described in this application refer to direct or indirect connections. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. For instance, A could be directly connected to C, and C could be directly connected to B, thus achieving a connection between A and B through C. It is also understood that the "A connecting to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0036] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. For example... Figure 1 As shown, electronic device 1 includes a power supply circuit 11 and a load 12. The power supply circuit 11 is used to receive an input voltage V. in and provides output voltage V out Power is supplied to load 12. In one embodiment, the input voltage V... in It can be powered by an external power source, or it can be powered by the internal power source of electronic device 1.

[0037] like Figure 1 The electronic device 1 provided in the illustrated embodiment can be a mobile phone, laptop computer, computer case, electric vehicle, smart speaker, smartwatch, or wearable device, etc. The power supply circuit provided in this application embodiment can be applied to, for example... Figure 1 In the electronic device 1 shown.

[0038] Figure 2 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. For example... Figure 2 As shown, the electronic device 1 includes a power supply circuit 11. The power supply circuit 11 is used to receive the input voltage V. in and provides output voltage V out This supplies power to the load subsequently connected to electronic device 1. In one embodiment, the input voltage V inIt can be powered by an external power source, or it can be powered by the internal power source of electronic device 1.

[0039] like Figure 2 The electronic device 1 provided in this embodiment can be a power adapter, charger, power bank, or other power supply device. The power circuit provided in this application embodiment can be applied to, for example... Figure 2 In the electronic device 1 shown.

[0040] In one embodiment of this application, the electronic device 1 may further include a plurality of power supply circuits 11, which provide an output voltage V. out Power is supplied to load 12. In one embodiment of this application, electronic device 1 may include multiple loads 12, and power supply circuit 11 provides multiple output voltages V. out The electronic device 1 may include multiple power supply circuits 11 and multiple loads 12, with the multiple power supply circuits 11 respectively providing multiple output voltages V. out Powers multiple loads 12.

[0041] In one embodiment of this application, the input voltage V in The power supply can be alternating current, and the internal power supply or power circuit 11 may include an AC / DC conversion circuit. In this embodiment, the input voltage V in The power supply can be direct current (DC), and the internal power source may include an energy storage device. The power supply circuit 11 may include a switching power supply. Accordingly, when the electronic device 1 is operating independently, the energy storage device of the internal power source can supply power to the power supply circuit 11.

[0042] In one embodiment of this application, the input voltage V in The power supply can be direct current (DC). The load 12 of the electronic device 1 can include one or more of a power-consuming device, an energy storage device, or an external device. In one embodiment, the load 12 can be a power-consuming device of the electronic device 1, such as a processor, a display, etc. In one embodiment, the load 12 can be an energy storage device of the electronic device 1, such as a battery. In one embodiment, the load 12 can be an external device of the electronic device 1, such as a display, a keyboard, or other electronic devices.

[0043] Figure 3 This is a schematic diagram of a power supply circuit provided in an embodiment of this application. Figure 3 As shown, a power supply circuit 11 with isolation function is used as an example. The input and output terminals of this power supply circuit 11 can be connected through a transformer. The power supply circuit 11 includes a control circuit 111, a switching power supply 112, and a rectifier circuit 113. The switching power supply 112 is used to receive the input voltage V provided by the input power supply. inThe rectifier circuit 113 rectifies the output voltage V2 provided by the switching power supply 112 to provide the output voltage V2. out The control circuit 111 is used to output control signals to control the switching power supply 112.

[0044] In one embodiment, the switching power supply 112 includes either an asymmetrical half-bridge (AHB) flyback converter circuit or an active clamp flyback (ACF) converter circuit. For example, the asymmetrical half-bridge flyback converter circuit includes a half-bridge circuit 1121 and a transformer 1122. The transformer 1122 includes a primary winding and a secondary winding. The half-bridge circuit 1121 includes at least one switching device. For example, the half-bridge circuit 1121 includes a main power transistor and an auxiliary power transistor. The half-bridge circuit 1121 may also include a resonant capacitor, etc.

[0045] The control circuit 111 is connected to the switching power supply 112. The control circuit 111 is used to output control signals to control the switching power supply 112. The control circuit provided in this application embodiment may include a pulse-width modulation (PWM) controller, a central processing unit (CPU), other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, etc.

[0046] The control signal output by control circuit 111 can be used to control the switching devices in half-bridge circuit 1121 to turn on and off. As the switching devices in half-bridge circuit 1121 cycle on and off, switching power supply 112 can provide output voltage V2. In one embodiment, control circuit 111 can send control signals to the switching devices, causing them to cycle on and off according to the frequency of the control signals. In one embodiment, the switching frequency of the switching devices in switching power supply 112 is equal to the frequency of the control signals.

[0047] like Figure 3 In the switching power supply 112 shown, the transformer 1122 includes a primary winding and a secondary winding. The half-bridge circuit 1121 is used to receive the input voltage V. inThis provides a primary winding voltage V1 to the primary winding of transformer 1122. The primary winding voltage V1 on the primary winding is coupled with the secondary winding to generate a secondary winding voltage V2 on the secondary winding. After rectification by rectifier circuit 113, the secondary winding voltage V2 is rectified, and the output voltage V provided by rectifier circuit 113 is... out This is the output voltage of the switching power supply 112.

[0048] In this embodiment of the application, the input voltage V of the switching power supply 112 in The output voltage V2 of the switching power supply 112 is also DC. In this embodiment, the primary winding refers to the winding placed on the primary side of the transformer 1122, corresponding to the input terminal of the switching power supply 112 (input voltage V). in The secondary winding refers to the winding located on the secondary side of transformer 1122, corresponding to the output terminal (output voltage V) of switching power supply 112. out ) windings.

[0049] In one embodiment, such as Figure 3 The power supply circuit 11 shown also includes an auxiliary winding 114 and an auxiliary winding circuit 115. The auxiliary winding 114 is coupled to the primary winding of the transformer 1122. The primary winding voltage V1 on the primary winding is coupled to the auxiliary winding to generate an auxiliary winding voltage V3. The auxiliary winding circuit 113 receives the voltage V3 provided by the auxiliary winding 114 and provides voltage V5 to the control circuit 111. That is, the auxiliary winding 114 supplies voltage V4 to the control circuit 111 via the auxiliary winding circuit 115. In this embodiment, the auxiliary winding circuit 115 may include a switching transistor and a capacitor. For example, the auxiliary winding circuit 115 may be a voltage regulator circuit, etc.

[0050] Figure 4 This is a schematic diagram of a power supply circuit provided in an embodiment of this application. Figure 4 As shown, a power supply circuit 11 with non-isolation function is used as an example. The power supply circuit 11 includes a control circuit 111 and a switching power supply 112. The switching power supply 112 can be a DC-DC converter circuit. The switching power supply 112 can be used to receive input voltage V. in And for the input voltage V in After voltage conversion, an output voltage V is provided. out The control circuit 111 is connected to the switching power supply 112 and can be used to control the switching devices in the switching power supply 112 to turn on and off, so that the switching power supply 112 provides the output voltage V. outIn one embodiment, the control circuit 111 can send a control signal to the switching device, causing the switching device to cycle on and off according to the frequency of the control signal. In one embodiment, the switching frequency of the switching device in the switching power supply 112 is equal to the frequency of the control signal.

[0051] Figure 5 A schematic diagram of a power supply circuit provided in an embodiment of this application shows, as follows: Figure 4 The switching power supply 112 can specifically be one of a boost circuit 1161, a buck circuit 1162, or a buck-boost circuit 1163. Each of the boost circuit 1161, buck circuit 1162, and buck-boost circuit 1163 includes at least one switching device, such as a switching transistor 11610 in the boost circuit 1161, a switching transistor 11620 in the buck circuit 1162, and a switching transistor 11630 in the buck-boost circuit 1163.

[0052] In the embodiments of this application, the main power transistor, auxiliary power transistor, and switching transistor can be diodes, transistors, metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), bipolar power transistors, or wide-bandgap semiconductor field-effect transistors, etc.

[0053] In the embodiments of this application, the main power transistor, auxiliary power transistor, and switching transistor can be different types of transistors. For example, the main power transistor is a MOSFET, the auxiliary power transistor is an IGBT, and the switching transistor is a wide-bandgap semiconductor field-effect transistor. Alternatively, the main power transistor, auxiliary power transistor, and switching transistor can be the same type of transistor. For example, the main power transistor, auxiliary power transistor, and switching transistor are all MOSFETs. It is understood that the embodiments of this application only exemplify MOSFETs as the main power transistor, auxiliary power transistor, and switching transistor, but the embodiments of this application do not limit the transistor types of the main power transistor, auxiliary power transistor, and switching transistor.

[0054] In this embodiment, the main power transistor, auxiliary power transistor, and switching transistor are driven by a high-level signal to turn on and a low-level signal to turn off. For example, the main power transistor turns on when it receives a high-level drive signal and turns off when it receives a low-level drive signal. It is understood that other driving methods can also be used for the main power transistor, auxiliary power transistor, and switching transistor in this embodiment, and this embodiment does not limit the driving method of the main power transistor, auxiliary power transistor, and switching transistor.

[0055] Figure 6 This is a waveform diagram of a control signal sent by a control circuit in the prior art. For example... Figure 6 The control circuit 111 provided can be applied to, for example... Figures 1-5 In any power supply circuit 11, the control circuit 111 can be used to send control signals to any switching device in the switching power supply 112. For example, the switching device can be a main power transistor, an auxiliary power transistor, or a switching transistor, etc.

[0056] like Figure 6 As shown, the control circuit 111 can generate a clock signal CLK. The clock signal CLK can be a pulse signal in high and low level form. The duration of each clock signal CLK being a high-level signal is denoted as the first duration T1. The duration of each clock signal CLK being a low-level signal is denoted as the second duration T2. ​​Alternatively, the second duration T2 is the time after which the control signal stops being sent following the first duration T1 of the high-level signal of each clock signal CLK. For example, the clock signals CLK can be sequentially denoted as C1, C2, C3… The control circuit 111 generates a clock signal CLK at time t… C1 After sending control signal C1 to the switching device for a first duration T1, the transmission of control signal C1 stops for a second duration T2. ​​Subsequently, at t C2 After sending control signal C2 to the switching device for a first duration T1, the transmission of control signal C2 stops for a second duration T2, and so on. The period of clock signal CLK is (T1+T2). The frequency of clock signal CLK is 1 / (T1+T2).

[0057] Subsequently, the clock signal CLK is used as the control signal G sent to the switching device. 10 The time-domain waveform S1. The control signal G that the control circuit 111 can send to the switching device. 10 The control signal G 10 They are sequentially labeled G1, G2, G3... Control signal G 10 The period is (T1+T2). Control signal G 10 The frequency of the switching device is 1 / (T1+T2) according to the received control signal G. 10The switching device cycles through on and off. It turns on based on a high-level control signal and turns off based on a low-level control signal. Therefore, the switching frequency of the device is equal to the control signal G. 10 The switching frequency of the switching device is 1 / (T1+T2). The switching period of the switching device is (T1+T2).

[0058] exist Figure 6 In the prior art shown, the control signal G 10 The period is T1+T2, and it remains constant. For example... Figure 6 Control signal G 10 As shown in the time-domain waveform S1, the timing of the high-level signal sent by the control circuit 111 in each cycle is the same as the difference between the timings of the two high-level signals before and after transmission. For example, t G2 Time, t G1 The difference between time points, and t G2 Time, t G3 The time difference is the same. Simultaneously, the control signal G... 10 The duration T1 of each high-level signal in the signal, as well as the second duration T2 after the high-level signal stops being sent, are also the same.

[0059] Due to control signal G 10 Since the period in the time domain is fixed, the frequency of the control signal G in the frequency domain is also fixed. For example... Figure 6 Control signal G 10 The frequency domain waveform F1 is shown, and the control signal G 10 The frequency remains at f0 and does not change with time t. In this embodiment, the values ​​of the period T0 and frequency f0 of the clock signal and each control signal are not limited and can be set according to the control circuit 111 and the switching devices.

[0060] The control signal G is analyzed using Fourier transform. 10 After expanding the time-domain waveform S1 in the frequency domain, the spectrum D of the control signal G can be obtained. b1 .like Figure 6 As shown, due to control signal G 10 It changes periodically in the time domain, therefore the control signal G 10 The spectrum is discrete. Specifically, for the control signal G... 10 The fundamental frequency f obtained after Fourier transform, and the control signal G 10 Energy exists at frequencies corresponding to harmonic orders such as f, 3f, 5f, 7f, 9f, etc. Furthermore, the energy at these frequencies gradually decreases as the harmonic order increases.

[0061] However, due to the control signal G 10For periodic signals, the spectrum is discrete, and the energy of the entire spectrum is concentrated on a finite number of frequency points, forming multiple narrow-band spectrums. Therefore, when the control signal G... 10 The spectral energy value is relatively large, and the control signal G sent by the control circuit 111 to the switching device 10 This may cause electromagnetic interference to the switching power supply 11 or other signals in the associated electronic equipment. In some specific applications, the control circuit 111 sends a control signal G to the switching device. 10 The high spectral energy can cause the power supply circuit 11 or electronic equipment to fail conducted interference (CE) and spectrum safety tests. Conducted interference testing is used to check the electromagnetic phenomena that cause interference between the internal signals of the power supply circuit 11 or the electronic equipment and other external devices, ensuring that the manufactured and designed power supply circuit 11 and electronic equipment meet certain electromagnetic interference limits.

[0062] Figure 7 This is a waveform diagram of a control signal sent by a control circuit in the prior art. Specifically, to solve... Figure 6 The existing technology has the problem of high spectral energy value of the control signal. The control circuit 111 can perform frequency modulation on the control signal. This changes the waveform of the control signal output by the control circuit 111 in the time domain, thereby reducing the spectral energy value of the control signal.

[0063] exist Figure 7 In the illustrated embodiment, the control circuit 111 modulates the clock signal CLK to obtain the control signal G. 20 . Figure 7 The control signal G is shown in the figure. 20 The time-domain waveform S2 and frequency-domain waveform F2 are given. Assume the clock signal CLK has a fixed frequency f0. Then the control signal G... 20 The frequency changes periodically around frequency f0, and the control signal G 20 The frequency varies within a certain range around the frequency f0 in each cycle.

[0064] In one embodiment, the control circuit 111 can use a modulation waveform M1 in the form of a triangular wave in the time domain to frequency modulate the clock signal CLK. For example, Figure 7 As shown, the modulation waveform M1 is periodically changing in the time domain, and its period M is... T1The value of is T, and it remains constant at T. In this embodiment, when the modulation waveform M1 changes within each cycle, the range of change is a maximum value of m0 + Δm and a minimum value of m0 - Δm, and the range of change remains constant. That is, the modulation depth Δm1 of the modulation waveform M1 that modulates the clock signal CLK is Δm, and it remains constant at Δm. Since the modulation waveform M1 is used to modulate the clock signal CLK, the frequency of change of the modulation waveform M1 can also be called the modulation frequency of the control circuit 111 for modulating the clock signal CLK.

[0065] Based on the modulated control signal G 20 As can be seen from the frequency domain waveform F2, after the clock signal CLK is frequency modulated by the modulation waveform M1, the resulting control signal G... 20 The frequency of the signal is periodically variable, and the pattern of this variation is consistent with the triangular wave pattern of the modulation waveform M1. For example, the control signal G... 20 The frequency at t f1 The maximum value f0 + Δf is reached at time t. f2 The minimum value f0-Δf is reached at time t. f3 The maximum value f0 + Δf is reached at time t. f4 The minimum value f0 - Δf is reached at each moment, and so on. And the control signal G... 20 The period of frequency change is equal to the period T of the modulated waveform M1, and the modulation depth Δf is equal to the modulation depth Δm of the modulated waveform M1.

[0066] Based on the modulated control signal G 20 As can be seen from the time-domain waveform S2, due to the control signal G 20 Since the frequency changes with time, the difference between the moment when the control circuit 111 sends a high-level signal in each cycle and the moment when it sends a high-level signal in the two cycles before and after is not the same, and the difference is related to the control signal G. 20 The frequencies are positively correlated. For example, at t f2 Near the time, control signal G 20 If the frequency is less than f0, then the frequency of the high-level signal sent by control circuit 111 is relatively small and the period is relatively large, t Gm Time and t Gm+1 The time difference is relatively large; at t f3 Control signal G near time 20 If the frequency is greater than f0, then the control circuit 111 sends a high-level signal at a higher frequency and with a shorter period, t Gh Time and t Gh+1 The time difference is small.

[0067] The control signal G is analyzed using Fourier transform. 20After expanding the time-domain waveform S2 in the frequency domain, the control signal G can be obtained. 20 Spectrum D b2 .like Figure 7 As shown, for the fundamental frequency f after Fourier transform, due to the control signal G 20 It does not change according to a fixed period, therefore the energy in the spectrum is expanded at the corresponding discrete frequency points. Taking the fundamental frequency f as an example, the control signal G... 10 The time-domain waveform S1, after being expanded in the frequency domain, has a spectral width of f. d1 -f d2 The energy value is D b1 Control signal G 20 The time-domain waveform S2, after being expanded in the frequency domain, has a spectral width of f. d3 -f d4 Since the energy of the control signal G remains constant, when the spectral width is wider, the energy value increases from D. b11 Reduced to D b21 This reduces the control signal G to some extent. 20 The spectral energy value.

[0068] However, because the modulation waveform M1 of the control circuit 111 modulates the clock signal CLK is periodically changing, the modulated control signal G... 20 The time-domain waveform S2 also changes periodically. Therefore, in practical applications, the spread-spectrum control signal G... 20 The energy dispersion in the frequency domain is relatively low. And when the control signal G... 20 The frequency domain energy is relatively large, and the degree of reduction in the energy value of the spectrum is reduced, which means that the power supply circuit 11 or the electronic equipment in which it is located still cannot pass the relevant safety test.

[0069] The control circuit 111, power supply circuit 11, and electronic equipment provided in this application can solve the technical problem in the prior art where the control signal output by the control circuit 111 of the switching power supply 112 has low energy dispersion and high energy value in the frequency domain, causing the power supply circuit or electronic equipment to fail safety tests. The technical solution of this application will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0070] Figure 8 This is a waveform diagram of a control signal transmitted by a control circuit provided in this application. Figure 8 In the example shown, the control circuit 111 can use a modulation waveform M2 in the form of a triangular wave in the time domain to frequency modulate the clock signal CLK, thereby obtaining the modulated control signal G. 30The modulation waveform M2 is periodically changing in the time domain, and the period M... T2 The duration varies randomly. For example, the duration of period Z1 is t. m2 -t m1 The duration of period Z2 is t. m3 -t m2 The duration of period Z3 is t. m4 -t m3 .

[0071] In one embodiment, the durations of the multiple periods of the modulated waveform M2 are different. The duration of at least one period of the multiple periods of the modulated waveform M2 is random. In one embodiment, the duration of at least one period of the multiple periods of the modulated waveform M2 is less than or greater than the duration of the previous period.

[0072] In one embodiment, the duration of at least one period among the multiple periods of the modulation waveform M2 can be a random number. Alternatively, in one embodiment, the duration of at least one period among the multiple periods of the modulation waveform M2 can be obtained by a random number. For example, the duration of at least one period can be determined by the sum of the duration T of a reference period and a first random number. When the reference period M... T1 The duration is T, and the first random number R1 corresponding to multiple periods of the modulation waveform M2 is denoted as R. 11 R 12 R 13 ...Then, through the reference period M... T1 The sum of the duration T and the first random number R1 yields the duration of multiple periods of the modulated waveform M2, which is T+R. 11 T+R 12 T+R 13 ...It can be seen that the duration is T+R 11 T+R 12 T+R 13 ...is subject to random variation.

[0073] In one embodiment, the value of the first random number R1 can be within a preset range. This preset range constrains the value of the first random number R1. This application embodiment does not limit the specific value of the preset range; it can be set according to the control circuit 111 and the switching device. In one embodiment, the duration of the period of the modulation waveform M2 can be much longer than that of the control signal G. 30 The length of the cycle.

[0074] By frequency modulation of the clock signal CLK based on the modulation waveform M2, the modulated control signal G can be obtained. 30 Modulated control signal G 30 The frequency domain waveform F3 and the time domain waveform S3 are as follows Figure 8As shown. In one embodiment, the modulation waveform M2 is used to modulate the clock signal CLK to obtain the control signal G. 30 The frequency of the modulation waveform M2 can also be called the modulation frequency that modulates the clock signal CLK. In cases such as... Figure 8 In the embodiment shown, the modulation frequency changes periodically, and the duration of each period is random.

[0075] According to control signal G 30 As can be seen from the frequency domain waveform F3, after frequency modulation of the clock signal CLK using the modulation waveform M2, the resulting control signal G... 30 The frequency is periodic and varies. And the control signal G... 30 The duration of each period varies randomly. For example, the duration of period Z1 is t. m2 -t m1 The time length of period Z2 is t m3 -t m2 The time length of period Z3 is t m4 -t m3 Control signal G 30 The duration of each cycle is different and randomly obtained. Control signal G 30 The minimum value of the frequency change amplitude within each cycle is f0-Δf, and the maximum value is f0+Δf. The amplitude remains constant at Δf in each cycle, and Δf is equal to the modulation depth Δm of the modulated waveform M2.

[0076] According to control signal G 30 As can be seen from the time-domain waveform S3, due to the control signal G 30 Since the frequency changes with time, the difference between the moment when the control circuit 111 sends a high-level signal in each cycle and the moment before and after sending two high-level signals is not the same, and the difference is related to the control signal G. 30 The frequency change is positively correlated. Control signal G 30 The duration of the frequency variation period is different. For example, in t m1 time-t m2 Between moments, control signal G 30 The frequency first increases and then decreases to complete one cycle. At t m2 time-t m3 Between moments, control signal G 30 The frequency first increases and then decreases to complete one cycle. At t m3 time-t m4 Between moments, control signal G 30 The frequency first increases and then decreases to complete one cycle. It can be seen that, due to the relatively short duration of period Z2, at time t... m2time-t m3 Between moments, control signal G 30 The frequency of change completes a cycle more quickly. The period Z3 has a longer duration, in t... m3 time-t m4 Between moments, control signal G 30 It completes a cycle of change at a slower frequency.

[0077] The control signal G is analyzed using Fourier transform. 30 After expanding the time-domain waveform S3 in the frequency domain, the control signal G can be obtained. 30 Spectrum D b3 .like Figure 8 As shown, for the fundamental frequency f after Fourier transform, due to the control signal G 30 It does not change according to a fixed period, and the control signal G 30 The duration of the periodic changes in the frequency is random, which greatly eliminates the control signal G. 30 The periodicity of the spectrum. Therefore, at the corresponding discrete frequency points, the spectrum is significantly expanded. Taking the fundamental frequency f as an example, the control signal G... 30 After the time-domain waveform S3 is expanded in the frequency domain, the spectral width of the fundamental frequency f is f. d5 -f d6 Due to control signal G 30 The energy remains constant, but as the spectral width increases, the energy value decreases to D. b31 This further reduces the control signal G. 30 The spectral energy value.

[0078] For the control circuit 111, when outputting the control signal, the control signal G can be adjusted according to the range of each cycle in multiple cycles. 30 The frequency of the control signal G emitted by the control circuit 111 causes the control signal G to be emitted by the control circuit 111 to be... 30 according to Figure 8 The time-domain waveform S3 and frequency-domain waveform F3 are shown in the diagram. Since the frequency and duration of the control signal are different in each cycle, the control circuit adjusts the frequency of the control signal within the corresponding range of each cycle as it changes over time.

[0079] For power supply circuit 11, when control circuit 111 outputs control signal G to the switching device of switching power supply 112... 30 The switching devices in the switching power supply 112 are controlled by the control signal G. 30 The switching frequency of the switching device is equal to the frequency of the control signal G. 30The frequency of the control signal varies with time within the range corresponding to each cycle, as controlled by the control circuit 111 in each cycle. The switching frequency of the switching device also varies with time within the range corresponding to each cycle, based on the frequency of the control signal.

[0080] Figure 9 This is a waveform diagram of a control signal transmitted by a control circuit provided in this application. Figure 9 In the example shown, the control circuit 111 can use a modulation waveform M3 in the form of a triangular wave in the time domain to frequency modulate the clock signal CLK, thereby obtaining the modulated control signal G. 40 The modulation waveform M3 is periodically changing in the time domain, with each cycle having a fixed duration T. However, the amplitude of the modulation frequency variation within each cycle is random, meaning the modulation depth varies randomly within each cycle. For example, within cycle Z1, the frequency variation ranges between m0-Δm1 and m0+Δm1, with a modulation depth of Δm1. Within cycle Z2, the frequency variation ranges between m0-Δm2 and m0+Δm2, with a modulation depth of Δm2. Within cycle Z3, the frequency variation ranges between m0-Δm3 and m0+Δm3, with a modulation depth of Δm3.

[0081] In one embodiment, the frequency changes with time at different amplitudes within multiple cycles of the modulated waveform M3. The frequency change amplitude in at least one cycle of the multiple cycles of the modulated waveform M3 is random. In one embodiment, the frequency change amplitude within at least one cycle of the multiple cycles of the modulated waveform M3 is greater than or equal to the frequency change amplitude in the previous cycle.

[0082] In one embodiment, the range of frequency variation within at least one period of the multiple periods of the modulation waveform M3 can be a random number. Alternatively, in one embodiment, the range of frequency variation within at least one period of the multiple periods of the modulation waveform M3 can be determined by the sum of a reference range and a second random number. For example, when the reference range is Δm, the multiple periods of the modulation waveform M3 are taken as a second random number R2, denoted as R. 21 R 22 R 23 ...Then, by summing the reference range Δm1 and the second random number, the range of frequency variation within multiple cycles of the modulated waveform M3 can be obtained as Δm+R. 21 , △m+R 22 , △m+R 23 ...

[0083] In one embodiment, the value of the second random number R2 can be within a preset range. This preset range constrains the value of the second random number R2. For example, the absolute value of the second random number R2 can be between [a, b]. For the maximum value b of the second random number R2, the maximum frequency of the modulation waveform M3 is Δm+b, and the control signal G... 40 The maximum frequency of the frequency domain waveform F4 is f0 + Δm + b, and the minimum frequency is f0 - Δmb. The control signal G... 40 The maximum frequency f0 + Δm + b is greater than the amplitude f0 of the reference range but less than 110% of the amplitude f0 of the reference range. Control signal G 40 The minimum frequency f0 - Δmb is less than the amplitude f0 of the reference range but greater than 90% of the amplitude f0 of the reference range. Therefore, by constraining the range of the second random number, the control signal G... 40 The frequency variation within multiple cycles varies within ±10% of the amplitude f0 of the reference range.

[0084] By frequency modulation of the clock signal CLK based on the modulation waveform M3, the modulated control signal G can be obtained. 40 Modulated control signal G 40 The time-domain waveform S4 and the frequency-domain waveform F4 are as follows Figure 9 As shown. In one embodiment, the modulation waveform M3 is used to modulate the clock signal CLK to obtain the control signal G. 40 The frequency of the modulation waveform M3 can also be called the modulation frequency that modulates the clock signal CLK. In cases such as... Figure 9 In the illustrated embodiment, the modulation frequency changes periodically, and the range of modulation frequency change within each cycle is random.

[0085] According to control signal G 40 As can be seen from the frequency domain waveform F4, after frequency modulation of the clock signal CLK using the modulation waveform M3, the resulting control signal G... 40 The frequency is periodically changing. Furthermore, within each changing period, the range of frequency variation is random. For example, the frequency variation range of period Z1 is between f0-Δf1 and f0+Δf1, and the amplitude of the frequency variation range within the period is Δf1, where Δf1 = Δm+R. 21 The frequency of period Z2 varies between f0-Δf2 and f0+Δf2, and the amplitude of the frequency variation within the period is Δf2, where Δf2 = Δm + R. 22 The frequency of period Z3 varies between f0-Δf3 and f0+Δf3, and the amplitude of the frequency variation within the period is Δf3, where Δf3 = Δm+R. 23 .

[0086] According to control signal G 40 As can be seen from the time-domain waveform S4, due to the control signal G 40 The frequency changes with time. The difference between the moment the control circuit 111 sends a high-level signal in each cycle and the moment before and after sending two high-level signals is not the same, and this difference is related to the control signal G. 40 The frequencies are positively correlated. Control signal G 40 The magnitude of the variation in frequency within each cycle is different. For example, in t m1 time-t m2 Between moments, control signal G 40 The frequency first increases and then decreases to complete one cycle. At t m2 time-t m3 Between moments, control signal G 40 The frequency first increases and then decreases to complete one cycle. At t m3 time-t m4 Between moments, control signal G 40 The frequency first increases and then decreases to complete one cycle. It can be seen that because the amplitude of the frequency variation range of period Z2 (f0-Δf2 and f0+Δf2) is larger, at t... m2 time-t m3 Between moments, control signal G 40 The variation in the interval between the mid-to-high level signals is more pronounced than in other periods. The amplitude of the frequency variation range of period Z3 (f0-Δf3 and f0+Δf3) is smaller, at t m4 time-t m3 Between moments, control signal G 40 The difference in the interval between the high and medium level signals is not as significant as in other cycles.

[0087] The control signal G is analyzed using Fourier transform. 40 After expanding the time-domain waveform S4 in the frequency domain, the control signal G can be obtained. 40 Spectrum D b4 .like Figure 9 As shown, for the fundamental frequency f after Fourier transform, due to the control signal G 40 It does not change according to a fixed period, and the control signal G 40 The frequency variation range within each cycle is random, which greatly eliminates the control signal G. 40 The periodicity of the spectrum. Therefore, at the corresponding discrete frequency points, the spectrum is significantly expanded. Taking the fundamental frequency f as an example, the control signal G... 40 The time-domain waveform S4, after being expanded in the frequency domain, has a spectral width of f. d7 -f d8Due to control signal G 40 The energy remains constant, but as the spectral width increases, the energy value decreases to D. b41 This further reduces the control signal G. 40 The spectral energy value.

[0088] For the control circuit 111, when outputting the control signal, the control signal G can be adjusted according to the range of each cycle in multiple cycles. 40 The frequency of the control signal G emitted by the control circuit 111 causes the control signal G to be emitted by the control circuit 111 to be... 40 according to Figure 8 The time-domain waveform S4 and frequency-domain waveform F4 are shown in the diagram. Since the amplitude of the frequency change range of the control signal is different in each cycle, the control circuit adjusts the frequency of the control signal to change with time within the corresponding range of each cycle.

[0089] For power supply circuit 11, when control circuit 111 outputs control signal G to the switching device of switching power supply 112... 40 The switching devices in the switching power supply 112 are controlled by the control signal G. 40 The switching frequency of the switching device is equal to the frequency of the control signal G. 40 The frequency of the control signal varies with time within the range corresponding to each cycle, as controlled by the control circuit 111 in each cycle. The switching frequency of the switching device also varies with time within the range corresponding to each cycle, based on the frequency of the control signal.

[0090] Figure 10 This is a waveform diagram of a control signal transmitted by a control circuit provided in this application. Figure 10 In the example shown, the control circuit 111 can use a modulation waveform M5 in the form of a triangular wave in the time domain to frequency modulate the clock signal CLK, thereby obtaining the modulated control signal G. 50 The modulation waveform M5 is periodically changing in the time domain, with the duration of each period varying randomly. Furthermore, the amplitude of the modulation frequency variation range within each period is also random, meaning the modulation depth varies randomly within each period. For example, the duration of period Z1 is t. m2 -t m1 The frequency variation range within period Z1 is between m0-Δm1 and m0+Δm1, with a variation amplitude of Δm1. The duration of period Z2 is t. m3 -t m2 The frequency variation range within period Z2 is between m0-Δm2 and m0+Δm2, with a variation amplitude of Δm2. The duration of period Z3 is t. m4 -t m3The frequency variation range within the period Z3 is between m0-Δm3 and m0+Δm3, with a variation amplitude of Δm3.

[0091] In one embodiment, the duration of at least one period among the multiple periods of the modulated waveform M5 is random, and the amplitude of at least one range among the multiple ranges of the multiple periods is random. The duration of at least one period may be determined by the sum of the duration T of a reference period and a first random number R1. The amplitude of at least one range may be the sum of the amplitude of a reference range and a second random number R2.

[0092] By frequency modulation of the clock signal CLK based on the modulation waveform M5, the modulated control signal G can be obtained. 50 Modulated control signal G 50 The time-domain waveform S5 and the frequency-domain waveform F5 are as follows Figure 10 As shown. In one embodiment, since the modulation waveform M5 is used to modulate the clock signal CLK to obtain the control signal G, the changing frequency of the modulation waveform M5 can also be called the modulation frequency for modulating the clock signal CLK. In such a case... Figure 10 In the illustrated embodiment, the modulation frequency changes periodically, and the duration of each period is random. Furthermore, the range of modulation frequency variation within each period is also random.

[0093] According to control signal G 50 As can be seen from the frequency domain waveform F5, after frequency modulation of the clock signal CLK using the modulation waveform M5, the control signal G... 50 The frequency varies with time. Furthermore, the duration of each cycle varies randomly, and the control signal G... 50 The duration of each cycle is different and randomly obtained. Meanwhile, in the control signal G... 50 Within the frequency variation period, the range of frequency variation is also random.

[0094] According to control signal G 50 As can be seen from the time-domain waveform S5, the difference between the moment when the control circuit 111 sends a high-level signal in each cycle and the moment before and after sending two high-level signals is not the same, and the difference is different from the control signal G. 50 The frequencies are positively correlated. For example, at t m1 time-t m2 Between moments, control signal G 50 The frequency first increases and then decreases to complete one cycle. At t m2 time-t m3 Between moments t and t, the frequency of the control signal G first increases and then decreases, completing one cycle. m3 time-t m4 Between moments, control signal G50 The frequency first increases and then decreases to complete one cycle. It can be seen that because the period Z2 is shorter and the range of frequency change is larger, at t... m2 time-t m3 Between moments, control signal G 50 The time interval difference between medium and high level signals changes more significantly and completes a cycle more quickly than other cycles. Period Z3 has a longer duration and a smaller frequency variation range, with a higher frequency variation at t... m4 time-t m3 Between moments, control signal G 50 The difference in the interval between the high and medium level signals is less noticeable than in other cycles and completes a cycle more slowly.

[0095] The control signal G is analyzed using Fourier transform. 50 After expanding the time-domain waveform S5 in the frequency domain, the control signal G can be obtained. 50 Spectrum D b5 .like Figure 10 As shown, for the fundamental frequency f after Fourier transform, due to the control signal G 50 It does not change according to a fixed period, and the control signal G 50 The duration of the frequency variation period is random, and the control signal G 50 The frequency variation range within each cycle is also random, greatly eliminating the control signal G. 50 The periodicity of the spectrum means that the energy in the spectrum is significantly expanded at the corresponding discrete frequency points. Taking the fundamental frequency f as an example, the time-domain waveform S3 of the control signal G, after frequency domain expansion, has a spectral width of f. d9 -f d10 Due to control signal G 50 The energy remains constant, but as the spectral width increases, the energy value decreases to D. b51 This further reduces the control signal G. 50 The spectral energy value.

[0096] For the control circuit 111, when outputting the control signal, the control signal G can be adjusted according to the range of each cycle in multiple cycles. 50 The frequency of the control signal G emitted by the control circuit 111 causes the control signal G to be emitted by the control circuit 111 to be... 50 according to Figure 10 The time-domain waveform S5 and frequency-domain waveform F5 shown are alternating. In each cycle, the control circuit adjusts the frequency of the control signal within the range corresponding to each cycle as it changes over time.

[0097] For power supply circuit 11, when control circuit 111 outputs control signal G to the switching device of switching power supply 112... 50The switching devices in the switching power supply 112 are controlled by the control signal G. 50 The switching frequency of the switching device is equal to the frequency of the control signal G. 50 The frequency of the control signal varies with time within the range corresponding to each cycle, as controlled by the control circuit 111 in each cycle. The switching frequency of the switching device also varies with time within the range corresponding to each cycle, based on the frequency of the control signal.

[0098] In summary Figure 8 , Figure 9 and Figure 10 The control circuit, power supply circuit, and electronic equipment of the switching power supply provided in this application, as shown in the embodiments, can be applied to, for example... Figures 1-5 In the power supply circuit 11 shown, the control circuit 111 can be used to output control signals to the switching devices in the switching power supply 112. The switching devices cyclically turn on and off according to the control signals at a switching frequency that varies with time. The switching frequency of the switching devices is equal to the frequency of the control signal.

[0099] In one embodiment, when the switching device cycles on and off, the switching power supply 112 containing the switching device can receive input voltage and provide output voltage. For example, in Figure 3 In the switching power supply 112 shown, when the main power transistor and auxiliary power transistor of the half-bridge circuit 1121 are cyclically turned on and off according to the frequency of the control signal, and when the main power transistor in the half-bridge circuit 1121 is turned on and the auxiliary power transistor is turned off, the half-bridge circuit 1121 adjusts according to the input voltage V. in The output voltage V2 is provided. When the main power transistor is off and the auxiliary power transistor is on, the half-bridge circuit 1121 provides the output voltage V2 based on the electrical energy stored in the capacitor. For example, in... Figure 5 In the shown switching power supply 112, the switching transistor of the switching power supply 112 cycles on and off according to the frequency of the control signal, and the switching power supply 112 cycles on and off according to the switching frequency. When the switching transistor is on, the switching power supply 112 operates according to the input voltage V. in It provides output voltage V2. When the switching transistor is turned off, the switching power supply 112 provides output voltage V based on the electrical energy stored in the capacitor. out .

[0100] When the control circuit 111 modulates the clock signal CLK to obtain the control signal, at least one of the duration of at least one of the multiple periods and the amplitude of at least one of the multiple ranges is random. Therefore, the uncertainty of the control signal output by the control circuit 111 is increased, the periodicity of the control signal G is further weakened, and the energy dispersion of the control signal G in the frequency domain is further increased. Even when the frequency domain energy of the control signal G is large, the spectral energy value of the control signal G output by the control circuit 111 can be reduced as much as possible, reducing the electromagnetic interference generated by the control signal G output by the control circuit 111, and ultimately ensuring that the power supply circuit 11 and the electronic equipment it is in can pass relevant safety tests.

[0101] Figure 11 This is a schematic diagram of a control circuit provided in this application. Figure 11 The control circuit 111 shown includes a clock source and a modulator. The clock source generates a clock signal CLK. The clock signal CLK is a periodic pulse signal with a fixed period and frequency. For example, the time-domain waveform of the clock signal can be as follows: Figure 6 The CLK is shown. The modulator is used to acquire the clock signal CLK and modulate the clock signal CLK according to multiple ranges in multiple cycles to generate the control signal. The generated control signal can be one or more of the control signals G3, G4, or G5 generated in the foregoing embodiments of this application.

[0102] In one embodiment, the clock signal CLK comprises multiple consecutive pulse signals. After receiving one pulse signal of the clock signal CLK, the control circuit 111 can frequency modulate the pulse signal of the current clock signal CLK according to the frequency corresponding to the current moment, obtain a control signal G, and then send the modulated control signal G to the switching device. The frequency at the current moment can vary with time according to the frequency domain waveforms F3, F4, or F5 of the control signal in the foregoing embodiments of this application.

[0103] For example, refer to Figure 8 After receiving the clock signal CLK at the current moment, the control circuit 111 can, based on the duration T of the reference period, generate a first random number R corresponding to the current moment. 11 The sum of these values ​​determines the duration of the modulation period at the current moment as T+R. 11 Subsequently, the control circuit 111 adjusts the current modulation period based on the duration T+R. 11 Determine the switching frequency F3 at the current moment, and modulate the clock signal CLK according to the switching frequency F3 at the current moment to obtain the control signal G3 at the current moment.

[0104] For example, refer to Figure 9After receiving the clock signal CLK at the current moment, the control circuit 111 can, based on the amplitude Δm of the switching frequency within the reference range of the period, and the second random number R corresponding to the current moment, 21 The sum of these values ​​determines the amplitude of the current switching frequency variation range as Δm, and the variation range is Δm + R. 21 Subsequently, the control circuit 111 adjusts the switching frequency according to the current time range of Δm+R. 21 Determine the switching frequency F4 at the current moment, and modulate the clock signal CLK according to the switching frequency F4 at the current moment to obtain the control signal G4 at the current moment.

[0105] Figure 12 A schematic diagram illustrating a scenario for conducting conductivity tests on the power supply circuit provided in this application. (Example) Figure 12 As shown, conducted interference testing can be performed on the power supply circuit 11 using test equipment 20. Test equipment 20 can be any conducted interference testing equipment that conforms to standard specifications. Test equipment 20 includes a line impedance stabilization network (LISN) and a spectrum analyzer. A power supply is used to power the LISN. The power supply can power the LISN through a live wire, a neutral wire, and a ground wire.

[0106] In one embodiment, this application reduces the spectral energy value of the control signal G sent by the control circuit 111 to the switching power supply 112 in the power supply circuit 11. When the switching devices in the switching power supply 112 turn on and off according to the lower-energy control signal G, the switching noise generated by the switching power supply 112 is reduced at the source. This reduces the impedance generated by the power supply circuit 11. When the impedance in the power supply circuit 11 is lower, the size and number of low-pass filters in the power supply circuit 11 can also be reduced accordingly. Therefore, this application also simplifies the structure of the power supply circuit 11, reduces the cost of the power supply circuit 11, and allows the power supply circuit 11 to pass relevant safety tests.

[0107] This application also provides an electronic device, including a control circuit 111 as provided in any embodiment of this application, or a power supply circuit 11 as provided in any embodiment of this application.

[0108] In the foregoing embodiments, the method executed by the control circuit 111 provided in the embodiments of this application has been described. To realize the functions of the methods provided in the embodiments of this application, the control circuit 111, as the execution subject, may include hardware structures and / or software modules, implementing the above functions in the form of hardware structures, software modules, or a combination of hardware structures and software modules. Whether a particular function is executed in the form of hardware structures, software modules, or a combination of hardware structures and software modules depends on the specific application and design constraints of the technical solution. It should be noted that the division of the various modules in the above device is merely a logical functional division; in actual implementation, they can be fully or partially integrated into a single physical entity, or physically separated. These modules can all be implemented by software through processing element calls; they can all be implemented in hardware; or some modules can be implemented by processing element calls to software, and some modules can be implemented in hardware. A separate processing element can be established, or it can be integrated into a chip in the above device. Furthermore, it can be stored in the memory of the above device as program code, and called and executed by a processing element of the above device. The implementation of other modules is similar. Furthermore, these modules can be integrated, either wholly or partially, or implemented independently. The processing element described here can be an integrated circuit with signal processing capabilities. During implementation, each step of the above method or each of the above modules can be completed through integrated logic circuits in the hardware of the processor element or through software instructions. For example, these modules can be one or more integrated circuits configured to implement the above method, such as one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), etc. As another example, when a module is implemented by a processing element calling program code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling program code. Furthermore, these modules can be integrated together as a system-on-a-chip (SOC).

[0109] In the above embodiments, the steps performed by the control circuit 111 can be implemented, in whole or in part, by software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0110] This application also provides a computer-readable storage medium storing computer instructions, which, when executed, can be used to perform any of the methods executed by the control circuit 111 in the foregoing embodiments of this application.

[0111] This application also provides a chip for executing instructions, the chip being used to perform any of the methods executed by the control circuit 111 as described above.

[0112] This application also provides a computer program product, which includes a computer program stored in a storage medium. At least one processor can read the computer program from the storage medium. When the at least one processor executes the computer program, it can implement any of the methods executed by the control circuit 111 as described above in this application.

[0113] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, magnetic disk, or optical disk.

[0114] Those skilled in the art will understand that, for the purpose of illustrating the technical solution of this application, the embodiments of this application are described separately by functional modules, and the circuit devices in each module may partially or completely overlap, which is not intended to limit the scope of protection of this application.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A control circuit for a switching power supply, the control circuit being used to output a control signal to control the switching frequency of the switching devices in the switching power supply, characterized in that, The control circuit is used for: The frequency of the control signal is adjusted according to multiple ranges in multiple cycles; In each cycle, the frequency of the control signal varies with time within the range corresponding to each cycle; the duration of at least one of the cycles differs from the duration of the other cycles, and / or the amplitude of at least one of the ranges differs from the amplitude of the other ranges. The control circuit is used for: Adjust the amplitude of at least one of the plurality of ranges to be greater than 90% of the amplitude of the reference range and less than the amplitude of the reference range; or, The magnitude of at least one of the plurality of ranges is adjusted to be greater than the magnitude of the reference range but less than 110% of the magnitude of the reference range.

2. The control circuit according to claim 1, characterized in that, At least one of the duration of at least one of the multiple cycles and the amplitude of at least one of the multiple ranges is random.

3. The control circuit according to claim 1 or 2, characterized in that, The control circuit is used for: The duration of at least one of the plurality of cycles is adjusted, wherein the duration of the at least one cycle is less than or greater than the duration of the previous cycle.

4. The control circuit according to claim 2, characterized in that, The control circuit is used for: The duration of at least one of the multiple cycles is randomly adjusted.

5. The control circuit according to claim 2, characterized in that, The control circuit is used for: The duration of the at least one period is adjusted based on the random number corresponding to at least one of the multiple periods and the duration of the base period.

6. The control circuit according to claim 1 or 2, characterized in that, The control circuit is used for: Adjust the amplitude of at least one of the plurality of ranges, wherein the amplitude of the at least one range is less than or greater than the amplitude of the previous range.

7. The control circuit according to claim 2, characterized in that, The control circuit is used for: The amplitude of the at least one range is adjusted based on the random number corresponding to at least one of the multiple periods and the reference range.

8. A power supply circuit, characterized in that, It includes a switching power supply and a control circuit, wherein the switching power supply includes at least one switching device, and the control circuit is the control circuit according to any one of claims 1-7.

9. The power supply circuit according to claim 8, characterized in that, The control circuit includes: Clock source, used to generate clock signals; A modulator is used to generate the control signal by modulating the clock signal according to the multiple ranges in the multiple cycles.

10. The power supply circuit according to any one of claims 8-9, characterized in that, At least one of the duration of at least one of the multiple cycles and the amplitude of at least one of the multiple ranges is random.

11. The power supply circuit according to any one of claims 8-9, characterized in that, The duration of at least one of the cycles is less than or greater than the duration of the previous cycle.

12. The power supply circuit according to any one of claims 8-9, characterized in that, The magnitude of the change in the switching frequency of the switching device over time in at least one of the multiple cycles is less than or greater than the magnitude of the change in the switching frequency of the switching device over time in the previous cycle.

13. The power supply circuit according to claim 8, characterized in that, The switching power supply includes one of a boost circuit, a buck circuit, or a buck-boost circuit.

14. The power supply circuit according to claim 8, characterized in that, The switching power supply includes either an asymmetric half-bridge flyback converter circuit or an active clamp flyback converter circuit.

15. An electronic device, characterized in that, It includes the control circuit as described in any one of claims 1-7, or the power supply circuit as described in any one of claims 8-14.

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