Power supply and control circuit thereof

Abstract

A power supply comprises a rectifying circuit, a regulating circuit, a power conversion circuit and a control circuit. The rectifier circuit rectifies a power source having a first frequency. The adjusting circuit adjusts the power supply through the switch assembly. The control circuit comprises a controller, a frequency disturbance module and a frequency setting module. The controller controls the switch assembly based on the control signal. A frequency perturbation module draws the power source to generate a perturbation signal having a first frequency. The frequency setting module generates a control signal according to the basic signal and the disturbance signal with the second frequency. Therefore, the disturbance signal and the basic signal which operate at different frequencies can enable the control signal to operate at the variable frequency, so that the switching action of the switching assembly operates at the variable frequency, the frequency is automatically changed, and the problem that the electromagnetic interference condition is too concentrated is solved.

Description

Technical Field

[0001] The present invention relates to a power supply, and more particularly to a power supply and its control circuit. Background Art

[0002] A power supply usually includes a circuit having at least one semiconductor switch component, such as: a pulse width modulation (PWM) circuit, a pulse frequency modulation (PFM), and a power factor correction (PFC) circuit. The control circuit adjusts the opening and closing timing, switching frequency, and duty cycle of the switch components in these circuits to improve the power conversion efficiency.

[0003] However, currently, the control circuit only controls the switch components at a fixed switching frequency. When performing electromagnetic interference (EMI) tests in this case, the quasi-peak (QP) in the average value waveform is likely to exceed the standard limit, and thus the EMI test cannot be passed. Summary of the Invention

[0004] One object of the present invention is to reduce electromagnetic interference.

[0005] Another object of the present invention is to reduce other circuit components used to reduce electromagnetic interference.

[0006] Another object of the present invention is to reduce copper loss to improve power efficiency.

[0007] To achieve the above and other objects, the present invention provides a power supply, including a rectification circuit for rectifying an input power supply having a first frequency; an adjustment circuit electrically connected to the rectification circuit, the adjustment circuit adjusting the power supply by at least one switch component; a power conversion circuit electrically connected to the adjustment circuit for converting the adjusted power supply and providing it to a load; and a control circuit electrically connected to the power conversion circuit and the adjustment circuit; the control circuit includes: a controller for controlling the switch component based on a control signal; a frequency perturbation module for extracting the power supply to generate a perturbation signal having the first frequency; and a frequency setting module electrically connected to the controller and the frequency perturbation module, the frequency setting module generating the control signal according to the perturbation signal and a base signal generated by itself, the base signal having a second frequency; wherein, based on the perturbation signal and the base signal operating at different frequencies, the control signal operates at a variable frequency, and the controller makes the switching operation of the switch component operate at the variable frequency based on the control signal.

[0008] In a preferred embodiment of the present invention, the frequency perturbation module includes an input terminal and an adjustment resistor. The input terminal is used to receive the power supply, and based on the adjustment resistor, a perturbation signal is generated and provided to the frequency setting module.

[0009] In a preferred embodiment of the present invention, the frequency setting module includes a timing resistor and a timing capacitor that are electrically connected to each other. A first node for receiving the perturbation signal is defined between the timing resistor and the timing capacitor. The timing resistor is also used to obtain a reference voltage from the controller.

[0010] In a preferred embodiment of the present invention, the adjustment circuit includes a power factor correction circuit and / or a pulse width modulation circuit. The power factor correction circuit and / or the pulse width modulation circuit each have at least one of the switching components, and each of the switching components is controlled by the controller.

[0011] In a preferred embodiment of the present invention, the power supply is a mains power supply with a voltage of 100V - 240V, and the adjustment resistor is configured with a high-resistance high-voltage resistor.

[0012] In a preferred embodiment of the present invention, the first frequency is 50Hz - 60Hz.

[0013] In a preferred embodiment of the present invention, the second frequency is 100kHz.

[0014] In a preferred embodiment of the present invention, the variable frequency is 110kHz - 114kHz.

[0015] The present invention also proposes a control circuit for a power supply. The power supply is used to convert the input power supply and provide it to a load. The control circuit is used to control the switching components in the adjustment circuit of the power supply and provide the ability to suppress electromagnetic interference. The control circuit includes: a controller that controls the switching actions of the corresponding switching components based on a control signal; a frequency perturbation module that is used to draw the power supply to generate a perturbation signal, and the perturbation signal has the same first frequency as the power supply; and a frequency setting module that is electrically connected to the controller and the frequency perturbation module. The frequency setting module generates the control signal according to the perturbation signal and a base signal generated by itself. The base signal has a second frequency. Wherein, based on the perturbation signal and the base signal operating at different frequencies, the control signal operates at a variable frequency, and the controller makes the switching actions of the switching components operate at the variable frequency based on the control signal.

[0016] In a preferred embodiment of the present invention, the frequency perturbation module includes an input terminal and an adjustment resistor. The input terminal is used to receive the power supply and generate the perturbation signal provided to the frequency setting module based on the adjustment resistor.

[0017] In a preferred embodiment of the present invention, the frequency setting module includes a timing resistor and a timing capacitor that are electrically connected to each other. A first node for receiving the perturbation signal is defined between the timing resistor and the timing capacitor. The timing resistor is also used to obtain a reference voltage from the controller.

[0018] In a preferred embodiment of the present invention, the adjustment circuit includes a power factor correction circuit and / or a pulse width modulation circuit. Each of the power factor correction circuit and / or the pulse width modulation circuit has at least one of the switching components, and each of the switching components is controlled by the controller.

[0019] In a preferred embodiment of the present invention, the power supply is a mains power supply with a voltage of 100V - 240V, and the adjustment resistor is configured with a high-resistance high-voltage resistor.

[0020] In a preferred embodiment of the present invention, the first frequency is 50Hz - 60Hz.

[0021] In a preferred embodiment of the present invention, the second frequency is 100kHz.

[0022] In a preferred embodiment of the present invention, the variable frequency is 110kHz - 114kHz.

[0023] Accordingly, based on the control signal generated by the perturbation signal and the base signal operating at different frequencies, the controller can operate at a variable frequency, forming an automatic change in frequency. At the same time, the operating frequency of the adjustment circuit also changes correspondingly (the switching frequency of the switch can change), which effectively disperses the electromagnetic interference situation. Without increasing the inductance and number of turns of the common mode inductor, the problem that the quasi-peak value (QP) in the EMI test is likely to exceed the standard limit can be solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the functional modules of a power supply according to an embodiment of the present invention.

[0025] Figure 2 It is a schematic diagram of the functional modules of a partial detailed circuit of a power supply according to an embodiment of the present invention.

[0026] Figure 3 It is an EMI test diagram of a power supply with a conventional control circuit.

[0027] Figure 4EMI test diagram of a power supply with the control circuit of the embodiment of the present invention.

[0028] Description of reference numerals

[0029] 100 Rectifier circuit

[0030] 200 Regulation circuit

[0031] 201 Switching component

[0032] 210 Power factor correction circuit

[0033] 211 Switching component

[0034] 220 Pulse width modulation circuit

[0035] 221 Switching component

[0036] 300 Control circuit

[0037] 310 Controller

[0038] 320 Frequency setting module

[0039] 330 Frequency perturbation module

[0040] 400 Power conversion circuit

[0041] 500 Load

[0042] Bs Base signal

[0043] CT Timing capacitor

[0044] Ds Perturbation signal

[0045] Fb Feedback signal

[0046] N1 Node

[0047] PS Power supply

[0048] R Adjustment resistor

[0049] Ramp Pin

[0050] RT Timing resistor

[0051] Vs Input terminal

[0052] S Control signal

[0053] SW Switching signal

[0054] SW1 First switching signal

[0055] SW2 Second switching signal

[0056] f1 First frequency

[0057] f2 Second frequency

[0058] fv Variable frequency Detailed implementation manners

[0059] To fully understand the purpose, features and effects of the present invention, based on the following specific embodiments and in conjunction with the accompanying drawings, a detailed description of the present invention is given as follows.

[0060] In the present invention, the terms "a" or "an" are used to describe units, components, devices, modules, devices, circuits or signals, etc. This is only for convenience of description and provides a general meaning to the scope of the present invention. Therefore, unless clearly indicated otherwise, such description should be understood to include one or at least one, and the singular also includes the plural.

[0061] In the present invention, the terms "including", "comprising", "having" or any other similar terms are not limited to only these elements listed in the present invention, but may include other elements that are not explicitly listed but are usually inherent in the described units, components, devices, modules, devices, circuits or signals.

[0062] In the present invention, the terms such as "first" or "second" and other similar ordinal words are used to distinguish or refer to the same or similar units, components, devices, modules, devices, circuits or signals, etc., and do not necessarily imply the order of these units, components, devices, modules, devices, circuits or signals in space or time. It should be understood that in some cases or configurations, the ordinal words can be used interchangeably without affecting the implementation of the present invention.

[0063] Please refer to Figure 1 , which is a schematic diagram of the functional modules of a power supply according to an embodiment of the present invention. The power supply includes: a rectification circuit 100, an adjustment circuit 200, a power conversion circuit 400, and a control circuit 300.

[0064] The rectification circuit 100 is used to rectify the input power supply PS. The frequency of the power supply PS is the first frequency f1. For example but not limited thereto, the rectification circuit 100 uses a full-wave rectification circuit structure to convert alternating current into direct current. The input power supply can be a mains power supply with a voltage in the range of 100V to 240V or a power supply with other voltage ranges.

[0065] The regulation circuit 200 is electrically connected to the rectification circuit 100 and the power conversion circuit 400 respectively, and is used to regulate the power rectified by the rectification circuit 100 and supply it to the subsequent power conversion circuit 400. The power conversion circuit 400 is used to perform power conversion and provide the required electrical energy for the subsequent load 500. The control circuit 300 is electrically connected to the regulation circuit 200 and the power conversion circuit 400 respectively, and the control circuit 300 controls the regulation circuit 200 accordingly based on the feedback signal Fb provided by the power conversion circuit 400. The rectification circuit 100, the regulation circuit 200, and the power conversion circuit 400 are common circuit configurations of a general power supply, and will not be elaborated here.

[0066] Among them, each switching component in the regulation circuit 200 is controlled by the control circuit 300, so the switching frequency of each switching component will correspond to the switching frequency initially set by the control circuit 300 (a fixed frequency, for example: 100 kHz). When the power supply operates, it is easy to generate a high electromagnetic interference phenomenon because each switching component operates at the same frequency, that is, the quasi-peak value of the electromagnetic interference test is likely to exceed the standard limit. Compared with other high-frequency components in the power supply, the operating frequency of each switching component in the regulation circuit 200 is relatively low. Although more or more expensive filtering components can be used in the rectification circuit 100, such as increasing the inductance value of the common-mode inductor, to solve the electromagnetic interference problem, this will lead to an increase in cost. In addition, a common-mode inductor with a higher inductance value has more turns of inductance coils, which not only increases the overall weight and occupied space of the circuit, but also increases the line loss rate (copper loss), thereby affecting the overall efficiency of the power supply.

[0067] In the embodiment of the present invention, a perturbation source is introduced to dynamically affect the operating frequency initially set by the control circuit 300, and then form a perturbation effect on the switching frequency of each switching component 201 in the regulation circuit 200, scatter the originally concentrated (due to the same frequency) electromagnetic interference phenomenon, and thus reduce the quasi-peak value.

[0068] The control circuit 300 includes: a controller 310, a frequency setting module 320, and a frequency perturbation module 330. The controller 310 generates a switching signal SW operating at a variable frequency based on the control signal S, so as to dynamically change the switching frequency of the switching component 201 in the regulation circuit 200. The frequency setting module 320 is electrically connected to the controller 310 and the frequency perturbation module 330. The frequency setting module 320 generates the control signal S according to the perturbation signal Ds from the frequency perturbation module 330 and the basic signal Bs generated by itself, that is, the control signal S is affected by both the perturbation signal Ds and the basic signal Bs. Among them, the perturbation signal Ds has a first frequency f1, and the basic signal Bs has a second frequency f2.

[0069] The controller 310 is, for example, an integrated circuit (IC) that controls the switching frequency of the switching component 201 through the switching signal SW, and adjusts the frequency of the switching signal SW through the configuration of the frequency setting module 320. First, in the conventional configuration without the frequency perturbation module 330, the control signal S is only affected by the basic signal Bs generated by the frequency setting module 320 and having the second frequency f2, and thus the switching signal SW also operates at the second frequency f2. That is to say, in the circuit configuration of the frequency setting module 320, for example, by the combination of a capacitor and a resistor, a charge-discharge condition is defined, and this charge-discharge condition enables the control signal S to operate at the second frequency f2. Specifically, this charge-discharge condition enables the frequency setting module 320 to generate a basic signal Bs, and this basic signal Bs is used to make the control signal S operate at the second frequency f2. That is, the conventional frequency setting module is used to determine the operating frequency of the conventional control signal. In other words, the basic signal is the frequency setting basis of the conventional control signal, used to enable the controller to generate a switching signal that only operates at the second frequency; on the contrary, in the embodiments of the present invention, by introducing a perturbation source, the frequency of the control signal has a variable characteristic.

[0070] Through the configuration of the frequency perturbation module 330, a perturbation source is introduced into the charge-discharge condition (used for synthesis with the basic signal), and the perturbation source comes from the power supply PS operating at the first frequency f1. The power supply PS itself has its own operating frequency (the first frequency f1). For example (but not limited thereto), the mains power supply has an operating frequency (or called the working frequency) of 50 Hz to 60 Hz. Therefore, using the power supply PS operating at the first frequency f1 as the perturbation signal Ds, and matching the basic signal Bs with the second frequency f2 of the frequency setting module 320 itself, since the perturbation signal Ds and the basic signal Bs operate at different frequencies, the control signal S generated by the frequency setting module 320 for the controller 310 has the characteristic of a variable frequency fv. Specifically, in a fixed frequency (for example, the basic signal Bs with the second frequency f2), adding another different frequency (the perturbation signal Ds with the first frequency f1) can generate a perturbation phenomenon, enabling the control signal S to have the characteristic of a variable frequency fv, and further enabling the controller 310 to generate a switching signal SW that also has the characteristic of a variable frequency fv, so as to achieve the purpose of dispersing the originally concentrated (due to the same frequency) electromagnetic interference phenomenon.

[0071] Next, please refer to Figure 2 , which is a functional module schematic diagram of a partial detailed circuit of a power supply according to an embodiment of the present invention.

[0072] The pin Ramp of the controller 310 is the oscillator timing node, which is a common configuration for general controllers. Traditionally, only by selecting the timing resistor RT and the timing capacitor CT, the operating frequency of the switching signal generated by the controller 310 is determined, but the known frequency is only a fixed frequency, showing a significant difference compared with the embodiments of the present invention.

[0073] According to some embodiments of the present invention, a disturbance source is additionally introduced at the node N1 between the timing resistor RT and the timing capacitor CT. The frequency disturbance module 330 has an input terminal Vs and an adjustment resistor R. The input terminal Vs is used to receive the power supply PS with the first frequency f1 from the rectifier circuit 100, and through the adjustment resistor R, a disturbance signal Ds with the first frequency f1 is generated and provided to the frequency setting module 320. Based on the synthesis of the two signals, namely the basic signal Bs with a different frequency and the disturbance signal Ds, a control signal S with the characteristic of a variable frequency fv can be correspondingly generated. This control signal S can enable the controller 310 to generate the first switching signal SW1 and the second switching signal SW2 operating at a variable frequency, and further control the switching frequencies of the corresponding switching components 211 and 221 in the regulation circuit 200.

[0074] In Figure 2 the embodiment, the regulation circuit 200 includes a power factor correction circuit 210 and a pulse width modulation circuit 220. The first switching signal SW1 is used to control each corresponding switching component 211 in the power factor correction circuit 210, and the second switching signal SW2 is used to control each corresponding switching component 221 in the pulse width modulation circuit 220. In other embodiments, the regulation circuit 200 may only have the power factor correction circuit 210 or only have the pulse width modulation circuit 220. In addition, the power factor correction circuit 210 and the pulse width modulation circuit 220 may also be controlled by different controllers, that is, there will be two sets of control circuits. In short, whether the controller 310 generates one switching signal SW or a plurality of switching signals SW1 and SW2, by introducing the disturbance source, the operating frequencies of the switching signals SW, SW1, and SW2 can show a variable characteristic, and thus the switching frequencies of the corresponding switching components also show a variable characteristic.

[0075] In other embodiments, the power supply PS introduced as a disturbance source can be a mains power supply with a voltage of 100V to 240V. The mains power supply usually has a frequency of 50 to 60Hz (i.e., corresponding to the aforementioned first frequency f1) and can be directly obtained from the rectifier circuit 100, which becomes a disturbance source that saves circuit costs and is easily obtained nearby. Among them, the adjustment resistor R can be configured with a high-value high-voltage resistor (for example, a 1MΩ resistor that can withstand 110V, a 5MΩ resistor that can withstand 220V) to limit the current of the disturbance source to avoid damaging the controller 310.

[0076] For example, when the frequency of the introduced disturbance source is 50Hz to 60Hz, and the second frequency f2 of the basic signal Bs under the cooperation of the timing resistor RT and the timing capacitor CT is 100kHz, the switching signals (such as: SW, SW1, SW2, etc.) generated by the controller 310 can exhibit a dynamic change working state where the frequency of the signal operates between 110kHz and 114kHz.

[0077] Next, please refer to Figure 3 and Figure 4 , Figure 3 is the EMI test diagram of a power supply with a conventional control circuit, Figure 4 is the EMI test diagram of a power supply with the control circuit of the embodiment of the present invention. The input voltage of the power supply is 115V. It can be seen from Figure 3 that at the starting point of the virtual coil, for the conventional power supply without introducing a disturbance source, since the switching components all operate at the same frequency, higher peaks are generated at low frequencies, which makes the quasi-peak (QP) in the average value waveform prone to exceeding the standard limit. In contrast, it can be seen from Figure 4 that at the starting point of the virtual coil, for the power supply after introducing a disturbance source, at the corresponding position of the original low frequency, the peak value of the electromagnetic interference intensity has been significantly reduced, which makes the quasi-peak (QP) in the average value waveform no longer exceed the standard limit.

[0078] To sum up, based on the control signal S generated by the disturbance signal Ds and the basic signal Bs operating at different frequencies, the switching signals SW, SW1, SW2 generated by the controller 310 can operate at a variable frequency fv, and then the switching actions of the switching components 201, 211, 221 can be operated at a variable frequency, achieving automatic frequency change and solving the problem of overly concentrated electromagnetic interference.

[0079] Form an automatic change in frequency, and at the same time cause the operating frequency of the adjustment circuit 200 to change correspondingly (the switching frequency of the switch can be changed), which effectively disperses the electromagnetic interference situation, and can solve the problem that the quasi-peak value (QP) in the EMI test is likely to exceed the standard limit without increasing the inductance and the number of turns of the common-mode inductor.

[0080] The present invention has been disclosed in the above with preferred embodiments. However, those skilled in the art should understand that the embodiments are only used to depict the present invention and should not be construed as limiting the scope of the present invention. It should be noted that all equivalent changes and substitutions to the embodiments should be considered as covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to what is defined by the scope of the patent application.

Claims

1. A power supply, characterized in that: include, A rectifier circuit, the rectifier circuit is used to rectify an input power supply, the power supply has a first frequency; A regulating circuit, the regulating circuit is electrically connected to the rectifying circuit, and the regulating circuit regulates the power supply by means of at least one switch component; A power conversion circuit, the power conversion circuit is electrically connected to the regulating circuit, converts the regulated power supply and provides it to a load; as well as, A control circuit, the control circuit being electrically connected to the power conversion circuit and the regulating circuit; The control circuit comprises: a controller, the controller controlling the switch assembly based on a control signal; a frequency disturbance module, the frequency disturbance module is used to draw the power supply to generate a disturbance signal, the disturbance signal has the first frequency; and A frequency setting module, the frequency setting module is electrically connected to the controller and the frequency disturbance module, the frequency setting module generates the control signal according to the disturbance signal and a basic signal generated by itself, and the basic signal has a second frequency; Wherein, based on the disturbance signal and the basic signal operating at different frequencies, the control signal operates at a variable frequency, and the controller causes the switching action of the switch component to operate at the variable frequency based on the control signal.

2. The power supply as claimed in claim 1, characterized in that: The frequency disturbance module includes an input terminal and an adjustment resistor. The input terminal is used to receive the power supply and generate the disturbance signal provided to the frequency setting module based on the adjustment resistor.

3. The power supply as claimed in claim 2, characterized in that: The frequency setting module includes a timing resistor and a timing capacitor electrically connected to each other, a first node for receiving the disturbance signal is defined between the timing resistor and the timing capacitor, and the timing resistor is also used to obtain a reference voltage from the controller.

4. The power supply as claimed in claim 1, wherein: The regulating circuit includes a power factor correction circuit and / or a pulse width modulation circuit. The power factor correction circuit and / or the pulse width modulation circuit each have at least one switch component, and each switch component is controlled by the controller.

5. The power supply according to any one of claims 2 to 4, characterized in that: The power supply is a commercial power supply with a voltage of 100V to 240V, and the adjustment resistor is configured with a high-resistance high-voltage resistor.

6. The power supply as claimed in claim 5, characterized in that: The first frequency is 50 Hz to 60 Hz.

7. The power supply as claimed in claim 6, wherein: The second frequency is 100 kHz.

8. The power supply as claimed in claim 7, wherein: The variation frequency is 110kHz to 114kHz.

9. A control circuit of a power supply, the power supply is used to convert input power to provide it to a load, the control circuit is used to control a switch component in a regulating circuit of the power supply and provide electromagnetic interference suppression capability, characterized in that: The control circuit comprises: A controller, wherein the controller controls the switching action of the corresponding switch component based on a control signal; a frequency disturbance module, the frequency disturbance module being used to draw from the power supply to generate a disturbance signal, the disturbance signal and the power supply having the same first frequency; and A frequency setting module, the frequency setting module is electrically connected to the controller and the frequency disturbance module, the frequency setting module generates the control signal according to the disturbance signal and a basic signal generated by itself, and the basic signal has a second frequency; Wherein, based on the disturbance signal and the basic signal operating at different frequencies, the control signal operates at a variable frequency, and the controller causes the switching action of the switch component to operate at the variable frequency based on the control signal.

10. The control circuit of the power supply as claimed in claim 9, characterized in that: The frequency disturbance module includes an input terminal and an adjustment resistor. The input terminal is used to receive the power supply and generate the disturbance signal provided to the frequency setting module based on the adjustment resistor.

11. The control circuit of the power supply as claimed in claim 10, characterized in that: The frequency setting module includes a timing resistor and a timing capacitor electrically connected to each other, a first node for receiving the disturbance signal is defined between the timing resistor and the timing capacitor, and the timing resistor is also used to obtain a reference voltage from the controller.

12. The control circuit of the power supply as claimed in claim 9, wherein: The regulating circuit includes a power factor correction circuit and / or a pulse width modulation circuit. The power factor correction circuit and / or the pulse width modulation circuit each have at least one switch component, and each switch component is controlled by the controller.

13. The control circuit of the power supply according to any one of claims 10 to 12, characterized in that: The power supply is a commercial power supply with a voltage of 100V to 240V, and the adjustment resistor is configured with a high-resistance high-voltage resistor.

14. The control circuit of the power supply as claimed in claim 13, characterized in that: The first frequency is 50 Hz to 60 Hz.

15. The control circuit of the power supply as claimed in claim 14, characterized in that: The second frequency is 100 kHz.

16. The control circuit of the power supply as claimed in claim 15, characterized in that: The variation frequency is 110kHz to 114kHz.

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