Power supply control circuit capable of switching output voltage

Abstract

The utility model discloses a power supply control circuit capable of switching output voltage. Comprising a main control chip U1, an inductor LF1, an inductor L1, a rectifier bridge BD1, a transformer T1, a transformer T2, a diode D1, a diode D2, a diode D5, a diode D7, a diode D10, a diode D11, a diode D12, a diode D13, a diode D14, a field effect transistor Q1, a field effect transistor Q2, an optical coupler U2, an optical coupler U3, a voltage stabilizing diode ZD1, a voltage stabilizing diode ZD2 and a controllable precision voltage stabilizing source IC1, and the R end of the controllable precision voltage stabilizing source IC1 is grounded through a change-over switch SW1 and a resistor R43. According to the utility model, the electronic components are less, the production cost is low, the output voltage control is accurate, the output voltage can be switched between 24V or 36V, the 24V and 36V are universal, and the use cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of control circuits, in particular to a power supply control circuit capable of switching output voltages. Background Art

[0002] With the advancement of science and technology and the improvement of people's living standards, LED light strips have become people's daily lighting and decorative lamps. During the use of LED light strips, a power supply is required to provide the LED light strips with stable current and voltage. Existing power supplies are generally divided into non-isolated power supplies and isolated power supplies, but the existing isolated power supply control circuit uses more electronic components, the output voltage control is not accurate, and the production cost is high. At the same time, the existing power supply can only output one voltage and cannot provide two voltages for different LED light strips. Consumers need to configure different power supplies to meet the use requirements of different LED light strips, which increases the use cost, is inconvenient to use, and the consumer experience is not good. Therefore, in order to avoid the shortcomings existing in the prior art, it is necessary to improve the prior art. Utility Model Content

[0003] The purpose of the utility model is to overcome the shortcomings and deficiencies in the prior art and to provide a power supply control circuit capable of switching output voltages.

[0004] The utility model is realized by the following technical solutions:

[0005] A power supply control circuit capable of switching output voltage, comprising a main control chip U1, an inductor LF1, an inductor L1, a rectifier bridge BD1, a transformer T1, a transformer T2, a diode D1, a diode D2, a diode D5, a diode D7, a diode D10, a diode D11, a diode D12, a diode D13, a diode D14, a field effect transistor Q1, a field effect transistor Q2, an optocoupler U2, an optocoupler U3, a voltage regulator diode ZD1, a voltage regulator diode ZD2 and a controllable precision voltage regulator IC1, wherein the input positive electrode of the rectifier bridge BD1 is connected to the seventh pin of the main control chip U1 through resistors R1, R2, R3 and R4, and the positive electrode of the diode D1 is connected to the first pin of the transformer T1 through a resistor R15. The positive electrode of the primary winding is connected, the negative electrode of the diode D1 is connected to the seventh pin of the main control chip U1, the output positive electrode of the rectifier bridge BD1 is connected to the drain of the field effect tube Q1, the gate of the field effect tube Q1 is connected to the positive electrode of the second primary winding of the transformer T1 through a resistor R19, the first pin of the main control chip U1 is connected to the collector of the optocoupler U2, the emitter of the optocoupler U2 is grounded, the anode of the optocoupler U2 is connected to the positive electrode of the voltage regulator diode ZD2, the negative electrode of the voltage regulator diode ZD2 is connected to the power supply output terminal V+ through a resistor R233, the cathode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage regulator IC1, the A terminal of the controllable precision voltage regulator IC3 is grounded, and the controllable precision voltage regulator IC4 is grounded. The R end of the controllable precision voltage regulator IC1 is grounded through a resistor R26, and the resistor R26 is connected in parallel with a resistor R27. The R end of the controllable precision voltage regulator IC1 is grounded with a resistor R43 through a switching switch SW1, and the resistor R43 is connected in parallel with a resistor R44. The second pin of the main control chip U1 is connected to the collector of the optical coupler U3, and the emitter of the optical coupler U3 is grounded. The anode of the optical coupler U3 is connected to the positive electrode of the voltage regulator diode ZD1, and the negative electrode of the voltage regulator diode ZD1 is connected to the power supply output terminal V+ through the resistor R23. The sixth pin of the main control chip U1 is connected to the negative electrode of the diode D10, and the diode D10 is connected in parallel with a capacitor C14. The positive electrode of the diode D10 is connected to the transformer The positive electrode of the primary winding of the transformer T2 is connected to the negative electrode of the diode D5 through the resistor R18, the positive electrode of the diode D5 is connected to the source of the field effect transistor Q1, the diode D5 is connected in parallel with a resistor R21, the negative electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1, the positive electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1 through the resistors R18, R21 and R19, the positive electrode of the second secondary winding of the transformer T2 is connected to the negative electrode of the diode D7 through the resistor R17, and the positive electrode of the diode D7 is connected to the gate of the field effect transistor Q2,The diode D10 is connected in parallel with a resistor R22, the drain of the field effect tube Q2 is connected to the negative electrode of the second primary winding of the transformer T1, the anode of the diode D2 is connected to the negative electrode of the second primary winding of the transformer T1, the cathode of the diode D2 is connected to the drain of the field effect tube Q1, the diode D2 is connected in parallel with a capacitor C15, the anode of the diode D11 is connected to the positive electrode of the secondary winding of the transformer T1, the cathode of the diode D11 is connected to the power output terminal V+, the anode of the diode D14 is connected to the negative electrode of the secondary winding of the transformer T1, and the cathode of the diode D14 is connected to the power output terminal V- through the inductor L1.

[0006] Furthermore, the eighth pin of the main control chip U1 is grounded through a capacitor C10, the eighth pin of the main control chip U1 is connected to the second pin of the main control chip U1 through a resistor R12, and the second pin of the main control chip U1 is grounded through a capacitor C8.

[0007] Further, the eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is connected to the third pin of the main control chip U1 through a resistor R11 and a capacitor C9, the third pin of the main control chip U1 is grounded through a capacitor C11, the third pin of the main control chip U1 is grounded through a resistor R13 and a resistor R9, the third pin of the main control chip U1 is connected to the negative electrode of the secondary winding of the transformer T2 through a resistor R13, the third pin of the main control chip U1 is connected to the positive electrode of the diode D7 through a resistor R13 and a resistor R20, and the third pin of the main control chip U1 is connected to the source of the field effect transistor Q2 through a resistor R13.

[0008] Further, the eighth pin of the main control chip U1 is connected to the fourth pin of the main control chip U1 through a resistor R11, the fourth pin of the main control chip U1 is grounded through a capacitor C8, and the fifth pin of the main control chip U1 is grounded.

[0009] Furthermore, it also includes a polarity capacitor C16, the cathode of the diode D1 is connected to the anode of the polarity capacitor C16, the cathode of the polarity capacitor C16 is grounded, the polarity capacitor C16 is connected in parallel with a capacitor C13, and the resistor R15 is connected in parallel with a resistor R16.

[0010] Furthermore, the cathode of the diode D10 is grounded through the resistor R14, and the cathode of the primary winding of the transformer T2 is grounded.

[0011] Furthermore, it also includes a diode D3, wherein the anode of the diode D3 is grounded, the cathode of the diode D3 is connected to the source of the field effect transistor Q1, and the diode D3 is connected in parallel with a capacitor C16.

[0012] Furthermore, the anode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through a resistor R24, the cathode of the optocoupler U2 is grounded through a capacitor C19, the cathode of the optocoupler U2 is connected to the R terminal of the controllable precision voltage-stabilizing source IC1 through a capacitor C18, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through a resistor R25 and a capacitor C25, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the power output terminal V- through a resistor R28, and the resistor R28 is connected in parallel with a resistor R29.

[0013] Further, the cathode of the diode D11 is connected to the anode of the diode D11 through the capacitor R20 and the resistor R31, the resistor R31 is respectively connected in parallel with the resistor R32 and the resistor R33, the cathode of the diode D12 is connected to the cathode of the diode D11, the cathode of the diode D12 is connected to the cathode and anode of the diode D12 through the capacitor C12 and the resistor R34, the resistor R34 is respectively connected in parallel with the resistor R35, the resistor R36 and the resistor R37, the cathode of the diode D13 is connected to the cathode of the diode D11, and the anode of the diode D13 is connected to the anode of the diode D11.

[0014] Furthermore, the model of the main control chip U1 is UC3845, and the switch SW1 is a SWSPST switch.

[0015] Compared with the prior art, the utility model sets a main control chip U1, a transformer T1, a transformer T2, a field effect transistor Q1 and a field effect transistor Q2 to stably control the output voltage and current, sets an optocoupler U2, an optocoupler U3, a voltage regulator diode ZD1, a voltage regulator diode ZD2 and a controllable precision voltage regulator IC1 to feedback information and adjust and compensate the voltage and current, sets a switching switch SW1 to connect the controllable precision voltage regulator IC1, and grounds through resistors R43 and R44. The opening and closing of the switching switch SW1 can stimulate the controllable precision voltage regulator IC1 to perform different adjustments and compensations on the voltage and current, thereby realizing the switching of different output voltages of the power supply. The output voltage can be switched to 24V or 36V, so that the power supply control circuit has fewer electronic components, the production cost is low, and the output voltage is precisely controlled. The switching switch SW1 can be used to switch the output voltage to 24V or 36V, and two voltages can be provided for use with different LED light strips. Consumers do not need to configure different power supplies to meet the use requirements of different LED light strips, thereby saving use costs, being easy to use, and providing consumers with a good use experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 The circuit schematic diagram of the power supply control circuit capable of switching output voltage of the utility model is shown in FIG. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] like Figure 1The utility model is a power supply control circuit with switchable output voltage, including a main control chip U1, an inductor LF1, an inductor L1, a rectifier bridge BD1, a transformer T1, a transformer T2, a diode D1, a diode D2, a diode D5, a diode D7, a diode D10, a diode D11, a diode D12, a diode D13, a diode D14, a field effect transistor Q1, a field effect transistor Q2, an optocoupler U2, an optocoupler U3, a voltage regulator diode ZD1, a voltage regulator diode ZD2 and a controllable precision voltage regulator IC1. The input positive electrode of the rectifier bridge BD1 is connected to the seventh pin of the main control chip U1 through resistors R1, R2, R3 and R4, and the positive electrode of the diode D1 is connected to the first pin of the transformer T1 through a resistor R15. The positive pole of the primary winding is connected, the negative pole of the diode D1 is connected to the seventh pin of the main control chip U1, the output positive pole of the rectifier bridge BD1 is connected to the drain of the field effect tube Q1, the gate of the field effect tube Q1 is connected to the positive pole of the second primary winding of the transformer T1 through the resistor R19, the first pin of the main control chip U1 is connected to the collector of the optocoupler U2, the emitter of the optocoupler U2 is grounded, the anode of the optocoupler U2 is connected to the positive pole of the voltage regulator diode ZD2, the negative pole of the voltage regulator diode ZD2 is connected to the power supply output terminal V+ through the resistor R233, the cathode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage regulator IC1, the A terminal of the controllable precision voltage regulator IC3 is grounded, the R terminal of the controllable precision voltage regulator IC1 is grounded through the resistor R26, and the resistor R26 is connected in parallel with a resistor R 27. The R end of the controllable precision voltage regulator IC1 is connected to the ground through the switch SW1 and the resistor R43. The resistor R43 is connected in parallel with a resistor R44. The second pin of the main control chip U1 is connected to the collector of the optocoupler U3. The emitter of the optocoupler U3 is grounded. The anode of the optocoupler U3 is connected to the positive electrode of the voltage regulator diode ZD1. The negative electrode of the voltage regulator diode ZD1 is connected to the power output terminal V+ through the resistor R23. The sixth pin of the main control chip U1 is connected to the negative electrode of the diode D10. The diode D10 is connected in parallel with a capacitor C14. The positive electrode of the diode D10 is connected to the positive electrode of the primary winding of the transformer T2. The positive electrode of the first secondary winding of the transformer T2 is connected to the negative electrode of the diode D5 through the resistor R18. The positive electrode of the diode D5 is connected to the source of the field effect transistor Q1. The diode D5 is connected in parallel with a resistor R21. The negative electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1. The positive electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1 through resistors R18, R21 and R19. The positive electrode of the second secondary winding of the transformer T2 is connected to the negative electrode of the diode D7 through resistor R17. The positive electrode of the diode D7 is connected to the gate of the field effect transistor Q2. The diode D10 is connected in parallel with a resistor R22. The drain of the field effect transistor Q2 is connected to the negative electrode of the second primary winding of the transformer T1. The positive electrode of the diode D2 is connected to the negative electrode of the second primary winding of the transformer T1. The negative electrode of the diode D2 is connected to the drain of the field effect transistor Q1.The diode D2 is connected in parallel with a capacitor C15, the anode of the diode D11 is connected to the anode of the secondary winding of the transformer T1, the cathode of the diode D11 is connected to the power output terminal V+, the anode of the diode D14 is connected to the cathode of the secondary winding of the transformer T1, and the cathode of the diode D14 is connected to the power output terminal V- through the inductor L1. By setting the main control chip U1, transformer T1, transformer T2, field effect tube Q1 and field effect tube Q2 to stably control the output voltage and current, setting the optocoupler U2, optocoupler U3, voltage regulator diode ZD1, voltage regulator diode ZD2 and controllable precision voltage regulator IC1 to feedback information and adjust and compensate the voltage and current, setting the switching switch SW1 to connect the controllable precision voltage regulator IC1, and grounding through resistors R43 and R44, the opening and closing of the switching switch SW1 can stimulate the controllable precision voltage regulator IC1 to adjust and compensate the voltage and current differently, and realize the switching of different output voltages of the power supply, and the output voltage can be switched to 24V or 36V, so that the electronic components of the power supply control circuit are less, the production cost is low, and the output voltage control is accurate. The switching switch SW1 can switch the output voltage to 24V or 36V, and can provide two voltages for different LED light strips. Consumers do not need to configure different power supplies to meet the use requirements of different LED light strips, saving use costs, easy to use, and consumers have a good use experience. ,

[0020] The eighth pin of the main control chip U1 is grounded through capacitor C10, the eighth pin of the main control chip U1 is connected to the second pin of the main control chip U1 through resistor R12, and the second pin of the main control chip U1 is grounded through capacitor C8, thereby improving the stability of feedback output and reference output.

[0021] The eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is connected to the third pin of the main control chip U1 through a resistor R11 and a capacitor C9, the third pin of the main control chip U1 is grounded through a capacitor C11, the third pin of the main control chip U1 is grounded through a resistor R13 and a resistor R9, the third pin of the main control chip U1 is connected to the negative electrode of the secondary winding of the transformer T2 through a resistor R13, the third pin of the main control chip U1 is connected to the positive electrode of the diode D7 through a resistor R13 and a resistor R20, and the third pin of the main control chip U1 is connected to the source of the field effect transistor Q2 through a resistor R13, thereby improving the stability and safety of sampling.

[0022] The eighth pin of the main control chip U1 is connected to the fourth pin of the main control chip U1 through resistor R11, and the fourth pin of the main control chip U1 is grounded through capacitor C8 to improve the frequency stability, accuracy and safety of the operation of the main control chip U1. The fifth pin of the main control chip U1 is grounded to improve the safety of the operation of the main control chip U1.

[0023] It also includes a polarity capacitor C16, the cathode of the diode D1 is connected to the anode of the polarity capacitor C16, the cathode of the polarity capacitor C16 is grounded, the polarity capacitor C16 is connected in parallel with a capacitor C13, and the resistor R15 is connected in parallel with a resistor R16, so as to improve the stability and safety of the voltage input of the transformer T1.

[0024] The cathode of the diode D10 is grounded through the resistor R14, and the cathode of the primary winding of the transformer T2 is grounded, thereby improving the stability and safety of the voltage input of the transformer T2.

[0025] It also includes a diode D3, the positive electrode of the diode D3 is grounded, the negative electrode of the diode D3 is connected to the source of the field effect tube Q1, and the diode D3 is connected in parallel with a capacitor C16 to improve the safety of the operation of the field effect tube Q1.

[0026] The anode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through the resistor R24, the cathode of the optocoupler U2 is grounded through the capacitor C19, the cathode of the optocoupler U2 is connected to the R terminal of the controllable precision voltage-stabilizing source IC1 through the capacitor C18, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through the resistor R25 and the capacitor C25, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the power output terminal V- through the resistor R28, and the resistor R28 is connected in parallel with a resistor R29, so as to improve the accuracy and stability of the feedback information between the optocoupler U2 and the controllable precision voltage-stabilizing source IC1 and the adjustment and compensation of the voltage and current.

[0027] The cathode of the diode D11 is connected to the anode of the diode D11 through the capacitor R20 and the resistor R31, the resistor R31 is respectively connected in parallel with the resistor R32 and the resistor R33, the cathode of the diode D12 is connected to the cathode of the diode D11, the cathode of the diode D12 is connected to the cathode and anode of the diode D12 through the capacitor C12 and the resistor R34, the resistor R34 is respectively connected in parallel with the resistor R35, the resistor R36 and the resistor R37, the cathode of the diode D13 is connected to the cathode of the diode D11, and the anode of the diode D13 is connected to the anode of the diode D11, so as to improve the stability of the output of the transformer T1.

[0028] As a specific implementation, the model of the main control chip U1 is UC3845, which improves the working efficiency of the power supply and reduces the cost of the power supply. The switching switch SW1 is a SWSPST switching switch, which is convenient for switching different voltages and locking.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A power supply control circuit capable of switching output voltage, characterized in that: The invention comprises a main control chip U1, an inductor LF1, an inductor L1, a rectifier bridge BD1, a transformer T1, a transformer T2, a diode D1, a diode D2, a diode D5, a diode D7, a diode D10, a diode D11, a diode D12, a diode D13, a diode D14, a field effect transistor Q1, a field effect transistor Q2, an optocoupler U2, an optocoupler U3, a voltage regulator diode ZD1, a voltage regulator diode ZD2 and a controllable precision voltage regulator IC1. The positive input electrode of the rectifier bridge BD1 is connected to the seventh pin of the main control chip U1 through resistors R1, R2, R3 and R4. The positive electrode of the diode D1 is connected to the positive electrode of the first primary winding of the transformer T1 through a resistor R15. The diode D The negative electrode of 1 is connected to the seventh pin of the main control chip U1, the output positive electrode of the rectifier bridge BD1 is connected to the drain of the field effect tube Q1, the gate of the field effect tube Q1 is connected to the positive electrode of the second primary winding of the transformer T1 through a resistor R19, the first pin of the main control chip U1 is connected to the collector of the optocoupler U2, the emitter of the optocoupler U2 is grounded, the anode of the optocoupler U2 is connected to the positive electrode of the voltage regulator diode ZD2, the negative electrode of the voltage regulator diode ZD2 is connected to the power supply output terminal V+ through a resistor R233, the cathode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage regulator IC1, the A terminal of the controllable precision voltage regulator IC3 is grounded, and the R terminal of the controllable precision voltage regulator IC1 is connected to the ground through a resistor R 26 is grounded, the resistor R26 is connected in parallel with a resistor R27, the R end of the controllable precision voltage source IC1 is grounded with the resistor R43 through the switching switch SW1, the resistor R43 is connected in parallel with a resistor R44, the second pin of the main control chip U1 is connected to the collector of the optical coupler U3, the emitter of the optical coupler U3 is grounded, the anode of the optical coupler U3 is connected to the positive electrode of the voltage zener diode ZD1, the negative electrode of the voltage zener diode ZD1 is connected to the power supply output terminal V+ through the resistor R23, the sixth pin of the main control chip U1 is connected to the negative electrode of the diode D10, the diode D10 is connected in parallel with a capacitor C14, the positive electrode of the diode D10 is connected to the positive electrode of the primary winding of the transformer T2, and the transformer T The positive electrode of the first secondary winding of the transformer T2 is connected to the negative electrode of the diode D5 through a resistor R18, the positive electrode of the diode D5 is connected to the source electrode of the field effect transistor Q1, the diode D5 is connected in parallel with a resistor R21, the negative electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1, the positive electrode of the first secondary winding of the transformer T2 is connected to the positive electrode of the second primary winding of the transformer T1 through resistors R18, R21 and R19, the positive electrode of the second secondary winding of the transformer T2 is connected to the negative electrode of the diode D7 through a resistor R17, the positive electrode of the diode D7 is connected to the gate electrode of the field effect transistor Q2, the diode D10 is connected in parallel with a resistor R22,The drain of the field effect tube Q2 is connected to the negative electrode of the second primary winding of the transformer T1, the positive electrode of the diode D2 is connected to the negative electrode of the second primary winding of the transformer T1, the negative electrode of the diode D2 is connected to the drain of the field effect tube Q1, the diode D2 is connected in parallel with a capacitor C15, the positive electrode of the diode D11 is connected to the positive electrode of the secondary winding of the transformer T1, the negative electrode of the diode D11 is connected to the power output terminal V+, the positive electrode of the diode D14 is connected to the negative electrode of the secondary winding of the transformer T1, and the negative electrode of the diode D14 is connected to the power output terminal V- through the inductor L1.

2. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The eighth pin of the main control chip U1 is grounded through a capacitor C10, the eighth pin of the main control chip U1 is connected to the second pin of the main control chip U1 through a resistor R12, and the second pin of the main control chip U1 is grounded through a capacitor C8.

3. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is grounded through a resistor R11 and a capacitor C8, the eighth pin of the main control chip U1 is connected to the third pin of the main control chip U1 through a resistor R11 and a capacitor C9, the third pin of the main control chip U1 is grounded through a capacitor C11, the third pin of the main control chip U1 is grounded through a resistor R13 and a resistor R9, the third pin of the main control chip U1 is connected to the negative electrode of the secondary winding of the transformer T2 through a resistor R13, the third pin of the main control chip U1 is connected to the positive electrode of the diode D7 through a resistor R13 and a resistor R20, and the third pin of the main control chip U1 is connected to the source of the field effect transistor Q2 through a resistor R13.

4. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The eighth pin of the main control chip U1 is connected to the fourth pin of the main control chip U1 through a resistor R11, the fourth pin of the main control chip U1 is grounded through a capacitor C8, and the fifth pin of the main control chip U1 is grounded.

5. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: It also includes a polarity capacitor C16. The cathode of the diode D1 is connected to the anode of the polarity capacitor C16. The cathode of the polarity capacitor C16 is grounded. The polarity capacitor C16 is connected in parallel with a capacitor C13. The resistor R15 is connected in parallel with a resistor R16.

6. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The cathode of the diode D10 is grounded through the resistor R14, and the cathode of the primary winding of the transformer T2 is grounded.

7. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: It also includes a diode D3, wherein the anode of the diode D3 is grounded, the cathode of the diode D3 is connected to the source of the field effect transistor Q1, and the diode D3 is connected in parallel with a capacitor C16.

8. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The anode of the optocoupler U2 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through a resistor R24, the cathode of the optocoupler U2 is grounded through a capacitor C19, the cathode of the optocoupler U2 is connected to the R terminal of the controllable precision voltage-stabilizing source IC1 through a capacitor C18, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the K terminal of the controllable precision voltage-stabilizing source IC1 through a resistor R25 and a capacitor C25, the R terminal of the controllable precision voltage-stabilizing source IC1 is connected to the power output terminal V- through a resistor R28, and the resistor R28 is connected in parallel with a resistor R29.

9. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The cathode of the diode D11 is connected to the anode of the diode D11 via a capacitor R20 and a resistor R31, the resistor R31 is respectively connected in parallel with a resistor R32 and a resistor R33, the cathode of the diode D12 is connected to the cathode of the diode D11, the cathode of the diode D12 is connected to the cathode and anode of the diode D12 via a capacitor C12 and a resistor R34, the resistor R34 is respectively connected in parallel with a resistor R35, a resistor R36 and a resistor R37, the cathode of the diode D13 is connected to the cathode of the diode D11, and the anode of the diode D13 is connected to the anode of the diode D11.

10. The power supply control circuit with switchable output voltage according to claim 1, characterized in that: The model of the main control chip U1 is UC3845, and the switch SW1 is a SWSPST switch.

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