An adjustable switching power supply

Abstract

The invention discloses an adjustable switching power supply, comprising a mains interface circuit, a rectifier circuit, a sampling circuit, a controller, a control signal circuit and a DC output circuit. The rectifier circuit rectifies the power input of the mains interface circuit into an envelope signal. The sampling circuit is connected to the DC output end of the adjustable switching power supply to obtain a power supply voltage and obtain a first sampling voltage according to the power supply voltage. The controller outputs a frequency modulation signal and a PWM adjustment signal according to the first sampling voltage. The control signal circuit outputs a matching control signal according to the received frequency modulation signal and the PWM adjustment signal, thereby outputting a DC voltage matching the power supply voltage in the DC output circuit. The invention can automatically adjust the output DC voltage according to the power supply voltage of the adjustable switching power supply in real time, thereby reducing the energy loss inside the adjustable switching power supply and improving the energy efficiency ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to an adjustable switching power supply. Background Art

[0002] Currently, the switching power supply can provide the corresponding DC supply voltage according to the power demand of the load, but the operating power of the load is not constant. When the load is reduced or disconnected, the switching power supply still needs to consume a lot of electrical energy, which is not conducive to saving energy. Summary of the invention

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] The embodiment of the present invention provides an adjustable switching power supply, which automatically adjusts the control signal according to its own output power supply voltage to reduce internal energy consumption and improve energy efficiency.

[0005] An embodiment of the present invention provides an adjustable switching power supply, comprising:

[0006] A mains interface circuit, comprising a ground terminal and a four-wire input terminal. According to different wiring modes, the mains interface circuit supports a single-phase power input in a first voltage range and supports a three-phase power input in a second voltage range. The first voltage range is 80V±10% to 265V±10%, and the second voltage range is 180V±10% to 440V±10%;

[0007] A rectifier circuit, connected to the output end of the mains interface circuit, for rectifying the mains input into an envelope signal;

[0008] a sampling circuit connected to a DC output terminal of the adjustable switching power supply to sample a supply voltage output by the adjustable switching power supply and output a first sampling voltage based on the supply voltage;

[0009] a controller connected to the sampling circuit to obtain the first sampling voltage, the controller comprising a frequency signal output pin and a PWM signal output pin, the controller outputs a frequency modulation signal at the frequency signal output pin according to the first sampling voltage, and the controller also outputs a PWM adjustment signal at the PWM signal output pin according to the first sampling voltage;

[0010] A control signal circuit, connected to the frequency signal output pin and the PWM signal output pin respectively, and used for outputting a control signal according to the received frequency modulation signal and the PWM adjustment signal;

[0011] A DC output circuit comprises a reference voltage input terminal and a control signal input terminal, wherein the reference voltage input terminal is connected to the output terminal of the rectifier circuit to receive the envelope signal, and the control signal input terminal is connected to the output terminal of the control signal circuit to receive the control signal. The DC output circuit is used to adjust the envelope signal according to the control signal to obtain a DC voltage, and output the DC voltage as the supply voltage.

[0012] According to some embodiments of the present invention, the AC power interface circuit also includes a common-mode inductor and a four-wire output port as an output end, the ground terminal is connected to a reference ground, and the four-wire input terminal includes three phase terminals and one neutral terminal, which correspond one-to-one to the four-wire output port through the common-mode inductor.

[0013] According to some embodiments of the present invention, the rectifier circuit includes four envelope rectifier devices, and the four envelope rectifier devices are respectively connected to four ports of the four-wire output port.

[0014] According to some embodiments of the present invention, the sampling circuit includes a first voltage divider circuit, the first voltage divider circuit includes a first sampling input terminal, a first voltage divider device, a second voltage divider device and a first sampling output terminal, the first sampling input terminal, the first voltage divider device and the second voltage divider device are connected in sequence, and the connection point between the first voltage divider device and the second voltage divider device is connected to the first sampling output terminal.

[0015] According to some embodiments of the present invention, the control signal circuit includes a control chip, a frequency signal processing circuit, a PWM signal processing circuit and a control signal output circuit, the control chip includes a first input pin, a second input pin and a control signal output pin, the input end of the frequency signal processing circuit is connected to the frequency signal output pin, the output end of the frequency signal processing circuit is connected to the first input pin, the input end of the PWM signal processing circuit is connected to the PWM signal output pin, and the output end of the PWM signal processing circuit is connected to the second input pin.

[0016] According to some embodiments of the present invention, the frequency signal processing circuit includes a first logic control chip, a first photoelectric coupler, and a second logic control chip, the first logic control chip is connected to the frequency signal output pin to receive the frequency modulation signal and output a first optical signal according to the frequency modulation signal, the control end of the first photoelectric coupler is connected to the first logic control chip to receive the first optical signal, and the electrical signal output end of the first photoelectric coupler is connected to the control chip and outputs a first control signal matching the first optical signal.

[0017] According to some embodiments of the present invention, the PWM signal processing circuit includes an amplifier device and a second photocoupler, the input end of the amplifier device is connected to the PWM signal output pin to receive the PWM adjustment signal and output a second optical signal according to the PWM adjustment signal, the output end of the amplifier device is connected to the control end of the second photocoupler, and the electrical signal output end of the second photocoupler is connected to the control chip and outputs a second control signal matching the second optical signal.

[0018] According to some embodiments of the present invention, the DC output circuit includes a transformer module, a positive output circuit and a negative output circuit, the primary side of the transformer module is connected to the reference voltage input terminal and the control signal input terminal, and the secondary side of the transformer module is connected to the positive output circuit and the negative output circuit.

[0019] According to some embodiments of the present invention, the positive output circuit includes a plurality of first capacitors connected in parallel, one end of the first capacitor serves as the positive output end of the DC output circuit, and the other end is grounded; the negative output circuit includes a plurality of second capacitors connected in parallel, one end of the second capacitor serves as the negative output end of the DC output circuit, and the other end is grounded; and a plurality of circuit board vias are arranged near the first capacitor and the second capacitor.

[0020] According to some embodiments of the present invention, a temperature sampling circuit is further included, the temperature sampling circuit includes a thermistor, the thermistor is arranged on the transformer module so that the temperature sampling circuit outputs a temperature sampling voltage according to the temperature of the transformer module, and the controller controls the frequency modulation signal and / or the PWM adjustment signal according to the size of the temperature sampling voltage.

[0021] The adjustable switching power supply provided by the embodiment of the present invention first obtains an envelope signal by connecting to the mains and rectifying it, and also obtains a first sampled voltage of the power supply voltage output by the adjustable switching power supply through a sampling circuit, and sends the first sampled voltage to a controller, and the controller gives a matching frequency modulation signal and a PWM adjustment signal according to the magnitude of the first sampled voltage, thereby adjusting the envelope signal according to the frequency modulation signal and the PWM adjustment signal, and obtaining a DC voltage matching the frequency modulation signal and the PWM adjustment signal; since the DC voltage output by the embodiment of the present invention is related to the power supply voltage output by the adjustable switching power supply, the output DC voltage can be automatically adjusted in real time according to the magnitude of the power supply voltage, thereby reducing the energy loss inside the adjustable switching power supply and improving the energy efficiency ratio.

[0022] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of circuit module connection provided by an embodiment of the present invention;

[0024] Figure 2 is a circuit diagram of a mains interface circuit provided by an embodiment of the present invention;

[0025] Figure 3 is a circuit diagram of a rectifier circuit provided by one embodiment of the present invention;

[0026] Figure 4 is a circuit diagram of a second conversion circuit provided by an embodiment of the present invention;

[0027] Figure 5 is a circuit diagram of a first conversion circuit provided by an embodiment of the present invention;

[0028] Figure 6 is a circuit diagram of a sampling circuit provided by an embodiment of the present invention;

[0029] Figure 7 is a pin diagram of a controller provided by an embodiment of the present invention;

[0030] Figure 8 is a circuit diagram of a frequency signal processing circuit provided by an embodiment of the present invention;

[0031] Fig. 9 is a circuit diagram of a PWM signal processing circuit provided by an embodiment of the present invention;

[0032] Fig.10 is a circuit diagram of a control signal output circuit provided by an embodiment of the present invention;

[0033] Fig.11 1 is a circuit diagram of a DC output circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] The embodiments of the present invention provide an adjustable switching power supply, a device and a computer-readable storage medium. By obtaining the response event of the target application to the input of the application operator, the corresponding multimedia information is extracted according to the response event and the multimedia information is played, so that the audience can know each input of the application operator, thereby assisting the application operator's explanation to enhance the audience's viewing experience.

[0036] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0037] Reference Figure 1 , an embodiment of the present invention provides an adjustable switching power supply, comprising:

[0038] A mains interface circuit, comprising a ground terminal and a four-wire input terminal. According to different wiring modes, the mains interface circuit supports a single-phase power input in a first voltage range and supports a three-phase power input in a second voltage range. The first voltage range is 80V±10% to 265V±10%, and the second voltage range is 180V±10% to 440V±10%;

[0039] A rectifier circuit, connected to the output end of the mains interface circuit, for rectifying the mains input into an envelope signal;

[0040] a sampling circuit connected to a DC output terminal of the adjustable switching power supply to sample a supply voltage output by the adjustable switching power supply and output a first sampling voltage based on the supply voltage;

[0041] a controller connected to the sampling circuit to obtain the first sampling voltage, the controller comprising a frequency signal output pin and a PWM signal output pin, the controller outputs a frequency modulation signal at the frequency signal output pin according to the first sampling voltage, and the controller also outputs a PWM adjustment signal at the PWM signal output pin according to the first sampling voltage;

[0042] A control signal circuit, connected to the frequency signal output pin and the PWM signal output pin respectively, and used for outputting a control signal according to the received frequency modulation signal and the PWM adjustment signal;

[0043] A DC output circuit comprises a reference voltage input terminal and a control signal input terminal, wherein the reference voltage input terminal is connected to the output terminal of the rectifier circuit to receive the envelope signal, and the control signal input terminal is connected to the output terminal of the control signal circuit to receive the control signal. The DC output circuit is used to adjust the envelope signal according to the control signal to obtain a DC voltage, and output the DC voltage as the supply voltage.

[0044] First, in order to adapt to different mains wiring systems, the mains interface circuit provides a three-phase five-wire interface, one of which is a ground terminal, and the remaining four wires correspond to four-wire input terminals. The ground port in the three-phase five-wire interface is connected to the reference ground, and the rest can be connected to the live wire and the neutral wire at will. This interface configuration can adapt to the mains access of different wiring systems such as three-phase four-wire and three-phase five-wire. Different input voltages can be used according to the different access methods of the live and neutral wires. Figure 2 For example, the ground terminal and the four-wire input terminal are ACGND, L1, L2, L3 and N respectively. The ground terminal ACGND is fixed for grounding. When you want to realize single-phase power supply input, you can select any two terminals from L1, L2, L3 and N and connect them in parallel, and the remaining two terminals are also connected in parallel. At this time, the mains interface circuit can obtain a larger input current under the premise of maintaining a single-phase voltage, thereby obtaining a larger input power. In this case, the mains interface circuit can obtain a voltage input in the first voltage range, that is, 80V±10% to 265V±10%, which corresponds to the voltage range of civil mains at home and abroad; for another example, L1, L2, L3 and N are not connected in parallel, and the four input terminals are connected to different phase lines respectively. At this time, the mains interface circuit realizes a three-phase power input in the second voltage range, that is, 180V±10% to 440V±10%, which corresponds to the voltage range of industrial three-phase power supply at home and abroad. Therefore, it can be seen that the interface circuit of the embodiment of the present invention can adapt to various power supply voltages at home and abroad, and has strong versatility.

[0045] Specifically, refer to Figure 2 , the AC interface circuit is respectively provided with three phase terminals corresponding to the three AC phase lines, and also provided with a neutral terminal corresponding to the AC neutral line and a ground terminal corresponding to the AC ground line. For the convenience of description, the above five ports are respectively represented by L1, L2, L3, N and ACGND, wherein the circuit arrangement of L1, L2, L3 and N ports is symmetrical, and a four-wire output port is led out through a common-mode inductor, wherein the four terminals connected to the AC and the four output ports of the four-wire output port (respectively represented by W1, W2, W3 and W4) correspond one to one, and capacitors are provided between adjacent phases; when the AC is connected, except for the ground line, the remaining phase lines and neutral lines do not need to be connected to the corresponding ports according to fixed rules, which is convenient for the operator to operate. The common-mode inductor is respectively provided with four inductors corresponding to the four-wire input, which is used to filter the common-mode electromagnetic interference signal; on the other hand, the AC interface circuit also includes four fuses, which are respectively provided after L1, L2, L3 and N ports, to provide overcurrent protection for each input.

[0046] After passing through the AC interface circuit, the AC power needs to be converted into DC power in order to obtain a DC voltage and a reference voltage such as 12V, 5V, etc. in the circuit. Therefore, a rectifier circuit is set after the AC interface circuit. Figure 3, the input end of the rectifier circuit is connected to the output end of the AC interface circuit, therefore based on the circuit structure of the above AC interface circuit, the rectifier circuit includes four envelope rectifier devices, and the four envelope rectifier devices are respectively connected to the four terminals of the four-wire output terminals, so as to rectify the four inputs of W1, W2, W3 and W4. Among them, the envelope rectifier device is implemented in the form of a packaged chip, and the four envelope rectifier devices are connected in series behind W1, W2, W3 and W4 respectively by connecting the corresponding pins of the packaged chip, and finally the four input ends of the rectifier devices are connected together to output the envelope signal. It is worth noting that Figure 3 The electrical signal obtained by rectification is represented by VDAC (the output end is represented by +VDAC), and the voltage value of VDAC is related to the input mains voltage. In order to obtain the working voltage of the components (DC 12V and 5V, etc.), further voltage conversion is required based on VDAC.

[0047] Based on the above VDAC voltage, the rectifier circuit further includes a first conversion circuit and a second conversion circuit, the first conversion circuit is used to obtain a positive and negative 12V DC voltage, and the second conversion circuit is used to obtain a 5V DC voltage. Specifically, referring to Figure 5 The first conversion circuit is connected to the VDAC output, and obtains +12V output and -12V output on the secondary side through a DC transformer T3 and a voltage value logic control IC. The first conversion circuit is provided with a fuse and a positive temperature coefficient thermistor behind the +VDAC port to protect the normal operation of the first conversion circuit. Figure 4 The second conversion circuit is connected to the +12V output of the first conversion circuit, and obtains a DC 5V voltage through a voltage regulator U48, wherein the voltage regulator U48 can adopt a three-terminal voltage regulator chip of the LM78xx series, which can directly convert a 12V DC output into a 5V DC output.

[0048] On the other hand, the sampling circuit includes a first voltage divider circuit, the first voltage divider circuit includes a first sampling input terminal, a first voltage divider device, a second voltage divider device and a first sampling output terminal, the first sampling input terminal, the first voltage divider device and the second voltage divider device are connected in sequence, and the connection point between the first voltage divider device and the second voltage divider device is connected to the first sampling output terminal. The sampling circuit is connected to the DC output terminal of the adjustable switching power supply to sample the power supply voltage. According to the first voltage divider circuit of this embodiment, the power supply voltage is sampled to obtain a first sampling voltage; wherein the first voltage divider device is Figure 6 In the figure, there are three series resistors, namely R157, R159 and R165. The second voltage divider is Figure 6In the figure, it is represented by R156. The resistance values ​​of the above four resistors can be adjusted according to the range of the controller recognition voltage, and the supply voltage of the DC output end of the adjustable switching power supply is represented by VDD, that is, the first sampling input end is connected to VDD, and the first sampling output end is represented by ADC3. Figure 7 It can be known that ADC3 is connected to the controller, and the controller controls the output of the frequency signal output pin and the PWM signal output pin according to the first sampling voltage of ADC3.

[0049] The sampling circuit also includes a second sampling circuit for the load working voltage, the second sampling circuit includes a second voltage divider circuit, the second voltage divider circuit includes a second sampling input terminal, a first voltage divider resistor, a second voltage divider resistor, a third voltage divider resistor and a second sampling output terminal, the first voltage divider resistor and the second voltage divider resistor are connected in series, the connection point of the first voltage divider resistor and the second voltage divider resistor is connected to the second sampling output terminal, the connection point of the first voltage divider resistor and the second voltage divider resistor is also connected to the third voltage divider resistor, and the third voltage divider resistor is connected to the second sampling input terminal. When there are multiple loads of the adjustable switching power supply, the number of the above-mentioned second voltage divider circuits can be set according to the number of loads, as long as the controller has enough pins to connect multiple second sampling output terminals; refer to Figure 6 In one embodiment, the two output voltages of the power amplifier (respectively represented by ch1out and ch2out) are sampled. Figure 6 Two second voltage divider circuits are provided, and the circuit forms of the two second voltage divider circuits are the same. The final sampled voltages are outputted by ADC7 and ADC6 respectively.

[0050] After the first sampling voltage is obtained in the above manner, the controller can perform operation control according to the voltage value of the first sampling voltage. Figure 7 , Figure 7 The pin diagram of one of the controllers is shown in Figure 7In the figure, MCU is used to represent the controller, which is connected to ADC3 to obtain the first sampling voltage, and outputs the frequency modulation signal and the PWM adjustment signal through the frequency signal output pin (represented by PB3) and the PWM signal output pin (represented by PB2) respectively. The controller outputs the frequency modulation signal and the PWM adjustment signal matching the working voltage according to the level of the first sampling voltage obtained by sampling, so that the control signal circuit obtains the corresponding control signal, and finally the DC output circuit outputs the DC voltage matching the first sampling voltage. Taking the power amplifier as an example, when the power of the power amplifier decreases, the voltage value required by the power amplifier is greatly reduced, that is, the first sampling voltage decreases. In order to match the power amplifier in the low voltage state, the embodiment of the present invention adjusts the frequency modulation signal and the PWM adjustment signal based on the size of the first sampling voltage, so that the control signal output by the control signal circuit has a narrow pulse width based on frequency modulation, thereby reducing the DC voltage output by the DC output circuit, reducing the energy consumed inside the adjustable switching power supply, and thus improving the energy efficiency ratio.

[0051] Based on this, the control signal circuit includes a control chip U28, a frequency signal processing circuit, a PWM signal processing circuit and a control signal output circuit. Fig.10 The control chip U28 includes a first input pin, a second input pin and a pulse width output pin ( Fig.10 The input end of the frequency signal processing circuit is connected to the frequency signal output pin, and the output end of the frequency signal processing circuit is connected to the first input pin ( Fig.10 The input end of the PWM signal processing circuit is connected to the PWM signal output pin, and the output end of the PWM signal processing circuit is connected to the second input pin ( Fig.10 In the example, the a3 end and the a4 end are used to represent the Figure 8 The frequency signal processing circuit includes a first logic control chip U36, a first photocoupler U39 and a second logic control chip M1. The first logic control chip U36 is connected to the frequency signal output pin PB3 to receive the frequency modulation signal and output a first optical signal according to the frequency modulation signal. The control end of the first photocoupler U39 is connected to the first logic control chip U36 to receive the first optical signal. The electrical signal output end of the first photocoupler U39 is connected to the control chip U28 and outputs a first control signal matching the first optical signal. Fig. 9, the PWM signal processing circuit includes an amplifier device M2 and a second photocoupler U40, the input end of the amplifier device M2 is connected to the PWM signal output pin to receive the PWM adjustment signal and output a second optical signal according to the PWM adjustment signal, the output end of the amplifier device M2 is connected to the control end of the second photocoupler U40, the electrical signal output end of the second photocoupler U40 is connected to the control chip U28 and outputs a second control signal matching the second optical signal. Finally, the pulse width output pin is connected to the input end ( Fig.11 In the example, the same terminals $$$26 and $$$2611 are used to represent the same terminals.

[0052] Reference Fig.11 The DC output circuit includes a transformer module, a positive output circuit and a negative output circuit. The primary side of the transformer module is connected to the reference voltage input terminal and the control signal input terminal. The secondary side of the transformer module is connected to the positive output circuit and the negative output circuit. The positive output circuit includes a plurality of first capacitors connected in parallel (C53, C54, C58, C59, C61 and C64). One end of the first capacitor is used as the positive output terminal of the DC output circuit (represented by VDD), and the other end is grounded. The negative output circuit includes a plurality of second capacitors connected in parallel (C30, C37, C42, C43, C48 and C52). One end of the second capacitor is used as the negative output terminal of the DC output circuit (represented by VEE), and the other end is grounded. A plurality of circuit board vias are arranged near the first capacitor and the second capacitor to adapt to the situation of large current.

[0053] It is worth noting that the DC output circuit also includes an active absorption circuit, which is connected between the reference voltage input terminal and the voltage conversion module and is used to clamp and absorb voltage spikes to prevent damage to the DC output circuit.

[0054] In one embodiment, a temperature sampling circuit is further included, and the temperature sampling circuit includes a thermistor. The thermistor is arranged on the transformer module so that the temperature sampling circuit outputs a temperature sampling voltage according to the temperature of the transformer module, and the controller controls the frequency modulation signal and / or the PWM adjustment signal according to the magnitude of the temperature sampling voltage. By detecting the temperature of the transformer module through the thermistor, when the temperature of the transformer module is too high, the frequency modulation signal or the PWM adjustment signal of the controller can be directly cut off, or both signals can be cut off at the same time, so that the control signal output by the control signal circuit is reduced, the transformer module is cooled down, and the adjustable switching power supply is prevented from being damaged due to excessive temperature.

[0055] The embodiment of the present invention samples the DC voltage output by the DC output circuit and adjusts the control signal sent to the DC output circuit according to the first sampled voltage obtained by the sampling, thereby outputting a matching DC voltage, reducing the internal energy loss of the adjustable switching power supply, and thus improving the energy efficiency ratio. The embodiment of the present invention can be applied to charging piles, high-power adjustable switching power supplies, and power amplifier equipment of audio systems, etc., greatly reducing the power of the equipment at low load and no load, and improving energy utilization.

[0056] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Claims

1. An adjustable switching power supply, characterized in that: include: A mains interface circuit, comprising a ground terminal and a four-wire input terminal. According to different wiring modes, the mains interface circuit supports a single-phase power input in a first voltage range and supports a three-phase power input in a second voltage range. The first voltage range is 80V±10% to 265V±10%, and the second voltage range is 180V±10% to 440V±10%; A rectifier circuit, connected to the output end of the mains interface circuit, for rectifying the mains input into an envelope signal; a sampling circuit connected to a DC output terminal of the adjustable switching power supply to sample a supply voltage output by the adjustable switching power supply and output a first sampling voltage based on the supply voltage; a controller connected to the sampling circuit to obtain the first sampling voltage, the controller comprising a frequency signal output pin and a PWM signal output pin, the controller outputs a frequency modulation signal at the frequency signal output pin according to the first sampling voltage, and the controller also outputs a PWM adjustment signal at the PWM signal output pin according to the first sampling voltage; A control signal circuit, connected to the frequency signal output pin and the PWM signal output pin respectively, and used for outputting a control signal according to the received frequency modulation signal and the PWM adjustment signal; a DC output circuit, comprising a reference voltage input terminal and a control signal input terminal, wherein the reference voltage input terminal is connected to the output terminal of the rectifier circuit to receive the envelope signal, and the control signal input terminal is connected to the output terminal of the control signal circuit to receive the control signal, and the DC output circuit is used to adjust the envelope signal according to the control signal to obtain a DC voltage, and output the DC voltage as the supply voltage; Wherein, the mains interface circuit further includes a common-mode inductor and a four-wire output port as an output end, the ground terminal is connected to the reference ground, and the four-wire input terminal includes three phase terminals and one neutral terminal, which correspond to the four-wire output port one by one through the common-mode inductor; The sampling circuit includes a first voltage divider circuit, the first voltage divider circuit includes a first sampling input terminal, a first voltage divider device, a second voltage divider device and a first sampling output terminal, the first sampling input terminal, the first voltage divider device and the second voltage divider device are connected in sequence, and the connection point between the first voltage divider device and the second voltage divider device is connected to the first sampling output terminal; The control signal circuit comprises a control chip, a frequency signal processing circuit, a PWM signal processing circuit and a control signal output circuit, the control chip comprises a first input pin, a second input pin and a control signal output pin, the input end of the frequency signal processing circuit is connected to the frequency signal output pin, the output end of the frequency signal processing circuit is connected to the first input pin, the input end of the PWM signal processing circuit is connected to the PWM signal output pin, and the output end of the PWM signal processing circuit is connected to the second input pin; The frequency signal processing circuit includes a first logic control chip, a first photoelectric coupler, and a second logic control chip, wherein the first logic control chip is connected to the frequency signal output pin to receive the frequency modulation signal and output a first optical signal according to the frequency modulation signal, the control end of the first photoelectric coupler is connected to the first logic control chip to receive the first optical signal, and the electrical signal output end of the first photoelectric coupler is connected to the control chip and outputs a first control signal matching the first optical signal; The PWM signal processing circuit includes an amplifier device and a second photocoupler, wherein the input end of the amplifier device is connected to the PWM signal output pin to receive the PWM adjustment signal and output a second optical signal according to the PWM adjustment signal, the output end of the amplifier device is connected to the control end of the second photocoupler, and the electrical signal output end of the second photocoupler is connected to the control chip and outputs a second control signal matching the second optical signal.

2. The adjustable switching power supply according to claim 1, characterized in that: The rectifier circuit includes four envelope rectifier devices, and the four envelope rectifier devices are respectively connected to four ports of the four-wire output port.

3. The adjustable switching power supply according to claim 1, characterized in that: The DC output circuit includes a transformer module, a positive output circuit and a negative output circuit. The primary side of the transformer module is connected to the reference voltage input terminal and the control signal input terminal, and the secondary side of the transformer module is connected to the positive output circuit and the negative output circuit.

4. The adjustable switching power supply according to claim 3, characterized in that: The positive output circuit includes a plurality of first capacitors connected in parallel, one end of the first capacitor serves as the positive output end of the DC output circuit, and the other end is grounded. The negative output circuit includes a plurality of second capacitors connected in parallel, one end of the second capacitor serves as the negative output end of the DC output circuit, and the other end is grounded. A plurality of circuit board vias are arranged near the first capacitor and the second capacitor.

5. The adjustable switching power supply according to claim 3, characterized in that: It also includes a temperature sampling circuit, which includes a thermistor. The thermistor is arranged on the transformer module so that the temperature sampling circuit outputs a temperature sampling voltage according to the temperature of the transformer module, and the controller controls the frequency modulation signal and / or the PWM adjustment signal according to the size of the temperature sampling voltage.

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