Switching power supply power supply control circuit

Abstract

The embodiment of the utility model discloses a power supply control circuit of a switching power supply, which is arranged in the switching power supply and connected with a main power circuit of the switching power supply. The switching power supply control circuit comprises a sixth diode, a first step-down module, a charge pump circuit, a second step-down module, a fourth power supply winding and a third power supply winding, the dotted terminal of the fourth power supply winding is connected with the positive electrode of a tenth electrolytic capacitor with the negative electrode grounded and the input end of a first voltage reduction module through a sixth diode, the dotted terminal of the third power supply winding is connected with the synonym terminal of the fourth power supply winding and the input end of a charge pump circuit, and the synonym terminal of the third power supply winding is grounded. The output end of the charge pump circuit is connected with the input end of the second step-down module, and the output end of the first step-down module and the output end of the second step-down module are both connected with the positive electrode of the twelfth electrolytic capacitor with the negative electrode grounded.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supply circuits, and particularly to a switching power supply power supply control circuit. Background Art

[0002] In recent years, the energy efficiency standard of switching power supplies has become higher and higher. The current power supply circuit of switching power supplies has problems that the power supply voltage is too low during no-load output, resulting in system downtime, or the power supply voltage is too high to meet the power-saving requirements. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a switching power supply power supply control circuit to balance the power supply voltage during no-load output and the power-saving requirements.

[0004] To solve the above technical problem, the purpose of the utility model is achieved by the following technical solutions: A switching power supply power supply control circuit is provided, which is arranged in a switching power supply and is connected to the main power circuit of the switching power supply. The main power circuit includes a transformer. The switching power supply power supply control circuit includes a sixth diode, a first buck module, a charge pump circuit, a second buck module, and a fourth power supply winding and a third power supply winding coupled to the primary winding of the transformer. The same-name end of the fourth power supply winding is connected to the positive electrode of a tenth electrolytic capacitor with a negative electrode grounded and the input end of the first buck module through the sixth diode. The same-name end of the third power supply winding is connected to the different-name end of the fourth power supply winding and the input end of the charge pump circuit. The different-name end of the third power supply winding is grounded. The output end of the charge pump circuit is connected to the input end of the second buck module. The output ends of the first buck module and the second buck module are both connected to the positive electrode of a twelfth electrolytic capacitor with a negative electrode grounded.

[0005] The further technical solution thereof is: The charge pump circuit includes a ninth capacitor, a seventh diode, an eighth diode, and an eleventh electrolytic capacitor. The first end of the ninth capacitor is connected to the same-name end of the third power supply winding. The second end of the ninth capacitor is connected to the cathode of the seventh diode and the anode of the eighth diode. The cathode of the eighth diode is connected to the positive electrode of the eleventh electrolytic capacitor. The cathode of the eighth diode serves as the output end of the charge pump circuit. The negative electrode of the eleventh electrolytic capacitor and the anode of the seventh diode are both grounded.

[0006] The further technical solution thereof is: The capacitance value of the eleventh electrolytic capacitor is 8 to 12 times that of the ninth capacitor.

[0007] Its further technical solution is as follows: The main power circuit further includes an input circuit connected to the primary winding of the transformer. The input circuit includes a first electrolytic capacitor, a first switching tube, a second switching tube, a connecting inductor, and a sixth capacitor. The positive electrode of the first electrolytic capacitor and the first end of the first switching tube are connected to the voltage input terminal. The second end of the first switching tube is connected to the first end of the connecting inductor and the first end of the second switching tube. The second end of the second switching tube is connected to the first end of the sixth capacitor and the ground. The second end of the connecting inductor is connected to the terminal of the primary winding of the transformer with the opposite name. The second end of the sixth capacitor is connected to the terminal of the primary winding of the transformer with the same name. The negative electrode of the first electrolytic capacitor is grounded.

[0008] Its further technical solution is as follows: Both the first switching tube and the second switching tube are MOS tubes. The drain of the first switching tube is connected to the positive electrode of the first electrolytic capacitor and the voltage input terminal. The source of the first switching tube is connected to the first end of the connecting inductor and the drain of the second switching tube. The source of the second switching tube is connected to the first end of the sixth capacitor and the ground.

[0009] Its further technical solution is as follows: Both the first switching tube and the second switching tube are GaN transistors.

[0010] Its further technical solution is as follows: The main power circuit further includes an output circuit connected to the secondary winding of the transformer. The output circuit includes a fourth diode and a seventh electrolytic capacitor. The terminal of the secondary winding of the transformer with the same name is connected to the positive electrode of the seventh electrolytic capacitor. The terminal of the secondary winding of the transformer with the same name serves as the voltage output terminal. The negative electrode of the seventh electrolytic capacitor is grounded. The terminal of the secondary winding of the transformer with the opposite name is connected to the cathode of the fourth diode. The anode of the fourth diode is grounded.

[0011] Its further technical solution is as follows: The first step-down module and the second step-down module adopt an LDO step-down circuit.

[0012] Its further technical solution is as follows: The sum of the number of turns of the third power supply winding and the number of turns of the fourth power supply winding is 2 to 4 times the number of turns of the secondary winding of the transformer.

[0013] The beneficial technical effects of the present utility model are as follows: The power supply control circuit of the switching power supply of the present utility model is connected to the main power circuit of the switching power supply. By connecting the first buck module to the same-name end of the fourth power supply winding coupled to the primary winding of the transformer of the main power circuit, and a sixth diode is electrically connected between the first buck module and the same-name end of the fourth power supply winding, and the charge pump circuit and the second buck module are connected to the same-name end of the third power supply winding coupled to the primary winding of the transformer of the main power circuit, it can better meet the power-saving requirements, and enable the switching power supply to work normally during no-load output, taking into account the balance between the supply voltage and the power-saving requirements during no-load output. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 It is the circuit schematic diagram of the power supply control circuit of the switching power supply provided by the embodiment of the present utility model;

[0016] Figure 2 It is the waveform diagram of the input voltage of the first buck module and the input voltage of the second buck module when the main power circuit of the power supply control circuit of the switching power supply provided by the embodiment of the present utility model is in the burst state;

[0017] Figure 3 It is the waveform diagram of the input voltage of the first buck module, the output voltage of the first buck module and the input voltage of the second buck module when the main power circuit of the power supply control circuit of the switching power supply provided by the embodiment of the present utility model is in the burst state;

[0018] Figure 4 It is the waveform diagram of the input voltage of the first buck module, the output voltage of the first buck module and the input voltage of the second buck module when the main power circuit of the power supply control circuit of the switching power supply provided by the embodiment of the present utility model is in the power-saving state. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are some, but not all, of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts fall within the protection scope of the present utility model.

[0020] Please refer to Figure 1As shown Figure 1 The figure is a circuit diagram of a switching power supply power control circuit provided by an embodiment of the present invention. The switching power supply power control circuit 11 is disposed in the switching power supply and is connected to the main power circuit 12 of the switching power supply. The main power circuit 12 includes a transformer. The switching power supply power control circuit 11 includes a sixth diode D6, a first buck module LDO1, a charge pump circuit 13, a second buck module LDO2, and a fourth power supply winding AUX4 and a third power supply winding AUX3 coupled to the primary winding P2 of the transformer. The same-name terminal of the fourth power supply winding AUX4 is connected to the positive electrode of a tenth electrolytic capacitor C10 with the negative electrode grounded and the input terminal of the first buck module LDO1 after passing through the sixth diode D6. The same-name terminal of the third power supply winding AUX3 is connected to the different-name terminal of the fourth power supply winding AUX4 and the input terminal of the charge pump circuit 13. The different-name terminal of the third power supply winding AUX3 is grounded. The output terminal of the charge pump circuit 13 is connected to the input terminal of the second buck module LDO2. The output terminals of the first buck module LDO1 and the second buck module LDO2 are both connected to the positive electrode of a twelfth electrolytic capacitor C12 with the negative electrode grounded.

[0021] Among them, the main power circuit 12 includes a main power chip. The input voltage of the first buck module LDO1 is denoted as V4, the output voltage of the first buck module LDO1 is denoted as V5, the input voltage of the second buck module LDO2 is denoted as V6, and Figure 1 V4, V5, and V6 in represent the nodes corresponding to the voltages at the input terminal of the first buck module LDO1, the output terminal of the first buck module LDO1, and the input terminal of the second buck module LDO2. The switching power supply power control circuit 11 is connected to the main power circuit 12 of the switching power supply. By connecting the first buck module LDO1 to the same-name terminal of the fourth power supply winding AUX4 coupled to the primary winding P2 of the transformer of the main power circuit 12, and there is a sixth diode D6 electrically connected between the first buck module LDO1 and the same-name terminal of the fourth power supply winding AUX4, and connecting the charge pump circuit 13 and the second buck module LDO2 to the same-name terminal of the third power supply winding AUX3 coupled to the primary winding P2 of the transformer of the main power circuit 12, it can better meet the power-saving requirements and enable the switching power supply to work normally during no-load output, taking into account the balance between the supply voltage and the power-saving requirements during no-load output.

[0022] Specifically, the first buck module LDO1 and the second buck module LDO2 adopt LDO buck circuits. The LDO (Low Dropout Regulator) buck circuit is used to convert a large DC voltage into a low DC voltage. Of course, in some embodiments, the first buck module and the second buck module can be buck chips.

[0023] Specifically, in this embodiment, the sum of the number of turns of the third power supply winding AUX3 and the number of turns of the fourth power supply winding AUX4 is three times the number of turns of the secondary winding S2 of the transformer. Of course, in some embodiments, the sum of the number of turns of the third power supply winding AUX3 and the number of turns of the fourth power supply winding AUX4 is two times or four times the number of turns of the secondary winding S2 of the transformer. Preferably, the sum of the number of turns of the third power supply winding AUX3 and the number of turns of the fourth power supply winding AUX4 is two to four times the number of turns of the secondary winding S2 of the transformer.

[0024] Specifically, in this embodiment, the charge pump circuit 13 includes a ninth capacitor C9, a seventh diode D7, an eighth diode D8, and an eleventh electrolytic capacitor C11. The first end of the ninth capacitor C9 is connected to the same-name end of the third power supply winding AUX3. The second end of the ninth capacitor C9 is connected to the cathode of the seventh diode D7 and the anode of the eighth diode D8. The cathode of the eighth diode D8 is connected to the positive electrode of the eleventh electrolytic capacitor C11. The cathode of the eighth diode D8 serves as the output end of the charge pump circuit 13. The negative electrode of the eleventh electrolytic capacitor C11 and the anode of the seventh diode D7 are both grounded. The first end of the ninth capacitor C9 is the input end of the charge pump circuit 13.

[0025] Specifically, in this embodiment, the capacitance value of the eleventh electrolytic capacitor C11 is ten times the capacitance value of the ninth capacitor C9. Among them, the capacitance value of the eleventh electrolytic capacitor C11 can be 10 uf, and the capacitance value of the ninth capacitor C9 can be 1 uf. Of course, in some embodiments, the capacitance value of the eleventh electrolytic capacitor C11 can be eight times, nine times, eleven times, or twelve times the capacitance value of the ninth capacitor C9. Preferably, the capacitance value of the eleventh electrolytic capacitor C11 can be eight to twelve times the capacitance value of the ninth capacitor C9.

[0026] Combined with Figure 2 , Figure 2 shows the waveform diagrams of the input voltage of the first buck module and the input voltage of the second buck module when the main power circuit 12 is in the burst state. From Figure 2It can be known that when the main power circuit 12 is working, the input voltages of the first step-down module LDO1 and the second step-down module LDO2 both increase. When the main power circuit 12 is not working, the input voltage V4 of the first step-down module LDO1 and the input voltage V6 of the second step-down module LDO2 both decrease. Since in this embodiment, the sum of the number of turns of the third power supply winding AUX3 and the fourth power supply winding AUX4 is 3 times the number of turns of the secondary winding S2 of the transformer, the capacitance value of the eleventh electrolytic capacitor C11 is 10 times the capacitance value of the ninth capacitor C9, the increase in the input voltage V4 of the first step-down module LDO1 is higher than that of the input voltage V6 of the second step-down module LDO2, and the initial value of the input voltage V4 of the first step-down module LDO1 is greater than the initial value of the input voltage V6 of the second step-down module LDO2. Then, before the main power circuit 12 works next time, the input voltage V4 of the first step-down module LDO1 will not drop below the power supply voltage turn-off threshold of the main power chip of the main power circuit 12 of the switching power supply. Therefore, the main power circuit 12 can still work normally when the output is 5V without load. The set output voltage of the first step-down module LDO1 is slightly lower than the set output voltage of the second step-down module LDO2. Among them, the waveform diagrams of the input voltage of the first step-down module, the output voltage of the first step-down module, and the input voltage of the second step-down module when the switching power supply control circuit is in the burst state of the main power circuit are as Figure 3 shown.

[0027] Specifically, the output voltage of the charge pump circuit 13 is the input voltage V6 of the second step-down module LDO2. The relationship between the input voltage of the second step-down module LDO2 and the input voltage of the main power circuit 12 can be expressed by formula (1):

[0028] V6 = Vbus * [(N AUX3 + N AUX4 ) / N P2 (1)

[0029] In the formula, V6 represents the input voltage of the second step-down module LDO2, Vbus represents the input voltage of the main power circuit 12, N AUX3 represents the number of turns of the third power supply winding AUX3, N AUX4 represents the number of turns of the fourth power supply winding AUX4, and N P2 represents the number of turns of the primary winding P2 of the transformer.

[0030] As can be seen from Equation (1), the input voltage V6 of the second step-down module LDO2, which is the output voltage of the charge pump circuit 13, is independent of the output voltage of the main power circuit 12. When the main power circuit 12 is in the power-saving state, the input voltage V4 of the first step-down module LDO1 and the input voltage V6 of the second step-down module LDO2 are both greater than the power supply voltage turn-off threshold. The input voltage V4 of the first step-down module LDO1 is positively correlated with the output voltage of the main power circuit 12. The input voltage V4 of the first step-down module LDO1 is greater than the input voltage V6 of the second step-down module LDO2, and the output voltage of the second step-down module LDO2 is greater than the output voltage V5 of the first step-down module LDO1. Figure 4 Figure 4 shows a waveform diagram of the input voltage of the first step-down module, the output voltage of the first step-down module, and the input voltage of the second step-down module when the main power circuit of the switching power supply control circuit is in the power-saving state. Figure 4 In Figure 4 , the first step-down module LDO1 stops working, which can avoid the problem that the input voltage V4 of the first step-down module LDO1 is relatively high due to the relatively high output voltage, thereby avoiding the problem that the voltage difference between the input end and the output end of the first step-down module LDO1 is relatively large and cannot meet the power-saving requirements.

[0031] Specifically, in this embodiment, the main power circuit 12 further includes an input circuit 121 connected to the primary winding P2 of the transformer. The input circuit 121 includes a first electrolytic capacitor C1, a first switching tube M1, a second switching tube M2, a connecting inductor L1, and a sixth capacitor C6. The positive electrode of the first electrolytic capacitor C1 and the first end of the first switching tube M1 are connected to the voltage input terminal Vbus. The second end of the first switching tube M1 is connected to the first end of the connecting inductor L1 and the first end of the second switching tube M2. The second end of the second switching tube M2 is connected to the first end of the sixth capacitor C6 and the ground. The second end of the connecting inductor L1 is connected to the opposite-named end of the primary winding P2 of the transformer. The second end of the sixth capacitor C6 is connected to the same-named end of the primary winding P2 of the transformer. The negative electrode of the first electrolytic capacitor C1 is grounded. Among them, when the first switching tube M1 is turned on, the third power supply winding AUX3 charges the ninth capacitor C9 through the seventh diode D7. When the first switching tube M1 is turned off and the second switching tube M2 is turned on, the third power supply winding AUX3 and the ninth capacitor C9 jointly charge the eleventh electrolytic capacitor C11 through the eighth diode D8. The average value of the voltages at both ends of the sixth capacitor C6 is equal to the turns ratio of the primary and secondary sides multiplied by the output voltage of the main power circuit.

[0032] Specifically, both the first switching transistor M1 and the second switching transistor M2 are MOS transistors. The drain of the first switching transistor M1 is connected to the positive electrode of the first electrolytic capacitor C1 and the voltage input terminal Vbus. The source of the first switching transistor M1 is connected to the first end of the connection inductor L1 and the drain of the second switching transistor M2. The source of the second switching transistor M2 is connected to the first end of the sixth capacitor C6 and the ground. Of course, in some embodiments, both the first switching transistor M1 and the second switching transistor M2 are GaN (Gallium Nitride) transistors.

[0033] Specifically, the main power circuit 12 further includes an output circuit 122 connected to the secondary winding S2 of the transformer. The output circuit 122 includes a fourth diode D4 and a seventh electrolytic capacitor C7. The same-name terminal of the secondary winding S2 of the transformer is connected to the positive electrode of the seventh electrolytic capacitor C7. The same-name terminal of the secondary winding S2 of the transformer serves as the voltage output terminal VO. The negative electrode of the seventh electrolytic capacitor C7 is grounded. The opposite-name terminal of the secondary winding S2 of the transformer is connected to the cathode of the fourth diode D4. The anode of the fourth diode D4 is grounded.

[0034] In summary, the power supply control circuit of the switching power supply of the present invention is connected to the main power circuit of the switching power supply. By connecting the first buck module to the same-name terminal of the fourth power supply winding coupled to the primary winding of the transformer of the main power circuit, and there is a sixth diode electrically connected between the first buck module and the same-name terminal of the fourth power supply winding, and connecting the charge pump circuit and the second buck module to the same-name terminal of the third power supply winding coupled to the primary winding of the transformer of the main power circuit, it can better meet the power-saving requirements, and enable the switching power supply to work normally during no-load output, taking into account the balance between the supply voltage and the power-saving requirements during no-load output.

[0035] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A switching power supply power control circuit, characterized in that, It is provided in a switching power supply and is connected to the main power circuit of the switching power supply. The main power circuit includes a transformer. The switching power supply power supply control circuit includes a sixth diode, a first buck module, a charge pump circuit, a second buck module, and a fourth power supply winding and a third power supply winding coupled to the primary winding of the transformer. The same-name terminal of the fourth power supply winding is connected to the positive electrode of a tenth electrolytic capacitor with a negative electrode grounded and the input end of the first buck module after passing through the sixth diode. The same-name terminal of the third power supply winding is connected to the different-name terminal of the fourth power supply winding and the input end of the charge pump circuit. The different-name terminal of the third power supply winding is grounded. The output end of the charge pump circuit is connected to the input end of the second buck module. The output ends of the first buck module and the second buck module are both connected to the positive electrode of a twelfth electrolytic capacitor with a negative electrode grounded.

2. The switching power supply power control circuit according to claim 1, characterized in that The charge pump circuit includes a ninth capacitor, a seventh diode, an eighth diode, and an eleventh electrolytic capacitor. The first end of the ninth capacitor is connected to the same-name terminal of the third power supply winding. The second end of the ninth capacitor is connected to the cathode of the seventh diode and the anode of the eighth diode. The cathode of the eighth diode is connected to the positive electrode of the eleventh electrolytic capacitor. The cathode of the eighth diode serves as the output end of the charge pump circuit. The negative electrode of the eleventh electrolytic capacitor and the anode of the seventh diode are both grounded.

3. The switching power supply power control circuit according to claim 2, wherein The capacitance value of the eleventh electrolytic capacitor is 8 to 12 times that of the ninth capacitor.

4. The switching power supply power control circuit according to claim 1, wherein The main power circuit further includes an input circuit connected to the primary winding of the transformer. The input circuit includes a first electrolytic capacitor, a first switching tube, a second switching tube, a connecting inductor, and a sixth capacitor. The positive electrode of the first electrolytic capacitor and the first end of the first switching tube are connected to a voltage input terminal. The second end of the first switching tube is connected to the first end of the connecting inductor and the first end of the second switching tube. The second end of the second switching tube is connected to the first end of the sixth capacitor and the ground. The second end of the connecting inductor is connected to the different-name terminal of the primary winding of the transformer. The second end of the sixth capacitor is connected to the same-name terminal of the primary winding of the transformer. The negative electrode of the first electrolytic capacitor is grounded.

5. The switching power supply power control circuit according to claim 4, characterized in that, Both the first switching tube and the second switching tube are MOS tubes. The drain of the first switching tube is connected to the positive electrode of the first electrolytic capacitor and the voltage input terminal. The source of the first switching tube is connected to the first end of the connecting inductor and the drain of the second switching tube. The source of the second switching tube is connected to the first end of the sixth capacitor and the ground.

6. The switching power supply power control circuit according to claim 4, wherein Both the first switching tube and the second switching tube are GaN transistors.

7. The switch power supply control circuit according to claim 1, characterized in that The main power circuit further includes an output circuit connected to the secondary winding of the transformer. The output circuit includes a fourth diode and a seventh electrolytic capacitor. The same-named terminal of the secondary winding of the transformer is connected to the positive electrode of the seventh electrolytic capacitor. The same-named terminal of the secondary winding of the transformer serves as a voltage output terminal. The negative electrode of the seventh electrolytic capacitor is grounded. The different-named terminal of the secondary winding of the transformer is connected to the cathode of the fourth diode, and the anode of the fourth diode is grounded.

8. The switching power supply power control circuit according to claim 1, wherein The first step-down module and the second step-down module adopt an LDO step-down circuit.

9. The switching power supply power control circuit according to claim 1, characterized in that, The sum of the number of turns of the third power supply winding and the number of turns of the fourth power supply winding is 2 to 4 times the number of turns of the secondary winding of the transformer.

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