A power supply circuit with controllable output power

Abstract

The present invention relates to the technical field of circuit power supply, and discloses a power supply circuit with controllable output power. The power supply circuit includes a voltage division circuit, a current source circuit, a power control circuit, a voltage control circuit, and an output circuit; the voltage division circuit is used to output a corresponding divided voltage to the power control circuit according to the input voltage; the current source circuit is used to supply power to the power control circuit and the voltage control circuit; the output circuit is used to output the output voltage of the power supply circuit; the voltage control circuit is used to limit the output voltage to the output threshold voltage; the power control circuit is used to control the output power of the power supply circuit. When the input voltage does not exceed the power control threshold voltage, the output power is limited to the threshold power, and when the input voltage is higher than the power control threshold voltage, the output power is limited to be less than the threshold power and is inversely related to the input voltage. The above circuit reduces the volume of the power supply circuit and improves the safety and reliability of the power supply circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit power supply, and particularly relates to a power supply circuit with controllable output power. Background Art

[0002] Figure 1 The power supply circuit in the related art is shown. As Figure 1 shown, in the power supply circuit inside the chip, in order to increase the application range of the power supply circuit, its input voltage VIN is usually designed as a wide-range voltage, that is, the power supply circuit in the related art can achieve wide-range voltage input. However, Figure 1 it can be known that the output voltage VOUT always maintains a fixed value related to the voltage VF under the combined action of the first feedback resistor RF1, the second feedback resistor RF2, the MOS transistor MP, and the controller U1. Therefore, at this time, if the output power remains unchanged, that is, the output current is also always a fixed value, this will cause a large voltage difference across the two ends of the MOS transistor MP when the input voltage VIN is large, so that the MOS transistor MP needs to bear a large power.

[0003] Therefore, in order to make the MOS transistor MP able to bear this large power as much as possible in the power supply circuit in the related art, a high-power MOS transistor is usually adopted, which greatly increases the volume and cost of the power supply circuit; at the same time, since Figure 1 the output current of the power supply circuit shown in is usually determined by the load. At this time, if the output current increases to a large value, it is extremely easy to damage the MOS transistor MP when the input voltage VIN is large. Summary of the Invention

[0004] In view of this, the present invention provides a power supply circuit with controllable output power, so that when the input voltage is large, the output power can be appropriately reduced, so that a low-power switching transistor can be used for the switching transistor in the output circuit provided between the input voltage and the output voltage, and it is ensured that the switching transistor will not be damaged, thereby reducing the volume of the power supply circuit and improving the safety and reliability of the power supply circuit. The technical solution is as follows:

[0005] A power supply circuit with controllable output power is provided, and the power supply circuit includes a voltage division circuit, a current source circuit, a power control circuit, a voltage control circuit, and an output circuit;

[0006] The voltage division circuit is electrically connected to the power supply voltage terminal and is used for dividing the input voltage of the power supply voltage terminal; the voltage division circuit is also electrically connected to the power control circuit and is used for outputting a corresponding divided voltage to the power control circuit according to the input voltage;

[0007] The current source circuit is electrically connected to the first voltage terminal and is used for supplying power to the power control circuit and the voltage control circuit according to the first voltage of the first voltage terminal;

[0008] The input end of the output circuit is electrically connected to the power supply voltage terminal; the output circuit is used to output the output voltage of the power supply circuit; the output circuit is electrically connected to the voltage control circuit;

[0009] The voltage control circuit is electrically connected to the second voltage terminal and is used to limit the output voltage to the output threshold voltage according to the second voltage of the second voltage terminal;

[0010] The power control circuit is electrically connected to the third voltage terminal and is used to control the output power of the power supply circuit in combination with the voltage control circuit according to the third voltage of the third voltage terminal and the input voltage; when the input voltage does not exceed the power control threshold voltage, the power control circuit is used to limit the output power to the threshold power, and when the input voltage is higher than the power control threshold voltage, the output power is limited to be less than the threshold power and is inversely related to the input voltage.

[0011] In an optional implementation manner, the second voltage is less than the first voltage; the third voltage is less than the first voltage.

[0012] In an optional implementation manner, the voltage dividing circuit includes at least one voltage stabilizing diode, a first resistor, and a second resistor;

[0013] The power supply voltage terminal is grounded successively through at least one voltage stabilizing diode, the first resistor, and the second resistor; the power supply voltage terminal is also connected to the power control circuit successively through at least one voltage stabilizing diode and the first resistor.

[0014] In an optional implementation manner, the current source circuit includes a first current source, a third resistor, a third controllable current source, a fourth controllable current source, a fifth controllable current source, a sixth controllable current source, a seventh controllable current source, an eighth controllable current source, and a ninth controllable current source;

[0015] The first voltage terminal is grounded successively through the third resistor and the first current source; the first voltage terminal is also connected to the power control circuit through the third controllable current source; the first voltage terminal is also connected to the power control circuit through the fourth controllable current source; the first voltage terminal is also connected to the power control circuit through the fifth controllable current source; the first voltage terminal is also connected to the power control circuit through the sixth controllable current source; the first voltage terminal is also connected to the power control circuit through the seventh controllable current source; the first voltage terminal is also connected to the voltage control circuit through the eighth controllable current source; the first voltage terminal is also connected to the voltage control circuit through the ninth controllable current source;

[0016] The positive control terminals of the third controllable current source, the fourth controllable current source, the fifth controllable current source, the sixth controllable current source, the seventh controllable current source, the eighth controllable current source, and the ninth controllable current source are connected to the first voltage terminal; the negative control terminals of the third controllable current source, the fourth controllable current source, the fifth controllable current source, the sixth controllable current source, the seventh controllable current source, the eighth controllable current source, and the ninth controllable current source are connected between the third resistor and the first current source.

[0017] In an alternative embodiment, the ratio of the current value of the fourth controllable current source to the current value of the fifth controllable current source is 1:1; the ratio of the current value of the sixth controllable current source to the current value of the seventh controllable current source is 2:1; the ratio of the current value of the eighth controllable current source to the current value of the ninth controllable current source is 2:1.

[0018] In an alternative embodiment, the power control circuit includes a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a fifth switching transistor, a sixth switching transistor, a seventh switching transistor, an eighth switching transistor, a ninth switching transistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first controllable current source, and a second controllable current source;

[0019] The first voltage terminal is grounded through the third controllable current source, the first switching transistor, and the fourth resistor in sequence; the control terminal of the first switching transistor is connected to the divided voltage; the first voltage terminal is also grounded through the third controllable current source, the second switching transistor, and the fifth resistor in sequence;

[0020] The first voltage terminal is also grounded through the fourth controllable current source, the third switching transistor, and the fourth resistor in sequence; the first voltage terminal is also grounded through the fifth controllable current source, the fourth switching transistor, and the fifth resistor in sequence; the control terminal of the third switching transistor is connected to the control terminal of the fourth switching transistor; the control terminal of the third switching transistor is also connected to the input terminal of the third switching transistor;

[0021] The first voltage terminal is also grounded through the sixth resistor, the fifth switching transistor, and the seventh resistor in sequence; the control terminal of the fifth switching transistor is connected to the input terminal of the fourth switching transistor; the control terminal of the second switching transistor is grounded through the seventh resistor;

[0022] The first voltage terminal is also grounded sequentially through a sixth controllable current source, a sixth switching transistor, and a tenth resistor; the control terminal of the sixth switching transistor is connected to the third voltage terminal; the first voltage terminal is also grounded sequentially through a sixth controllable current source, a seventh switching transistor, and an eleventh resistor; the first voltage terminal is also connected to the control terminal of the seventh switching transistor through a first controllable current source; the positive control terminal of the first controllable current source is connected to the negative control terminal of the first controllable current source through a sixth resistor;

[0023] The first voltage terminal is also grounded sequentially through a seventh controllable current source and a second controllable current source; the positive control terminal of the second controllable current source is connected to the negative control terminal of the second controllable current source through a tenth resistor;

[0024] The first voltage terminal is also grounded sequentially through a twelfth resistor, an eighth switching transistor, and a thirteenth resistor; the control terminal of the eighth switching transistor is connected between the seventh controllable current source and the second controllable current source;

[0025] The control terminal of the ninth switching transistor is connected to the output terminal of the eighth switching transistor; the input terminal of the ninth switching transistor is connected to the voltage control circuit; the output terminal of the ninth switching transistor is grounded.

[0026] In an alternative embodiment, the resistance value of the fourth resistor is equal to the resistance value of the fifth resistor; the resistance value of the tenth resistor is equal to the resistance value of the eleventh resistor.

[0027] In an alternative embodiment, the voltage control circuit includes a tenth switching transistor, an eleventh switching transistor, a twelfth switching transistor, a fourteenth resistor, a fifteenth resistor, a seventeenth resistor, and a tenth controllable current source;

[0028] The first voltage terminal is grounded sequentially through an eighth controllable current source, a tenth switching transistor, and a fourteenth resistor; the control terminal of the tenth switching transistor is connected to the second voltage terminal; the first voltage terminal is also grounded sequentially through an eighth controllable current source, an eleventh switching transistor, and a fifteenth resistor; the control terminal of the eleventh switching transistor is electrically connected to the output circuit;

[0029] The first voltage terminal is also grounded sequentially through a ninth controllable current source and a tenth controllable current source; the positive control terminal of the tenth controllable current source is connected to the negative control terminal of the tenth controllable current source through a fourteenth resistor;

[0030] The control terminal of the twelfth switching transistor is connected to the input terminal of the ninth switching transistor; the input terminal of the twelfth switching transistor is electrically connected to the output circuit; the output terminal of the twelfth switching transistor is grounded through a seventeenth resistor.

[0031] In an alternative embodiment, the resistance value of the fourteenth resistor is equal to the resistance value of the fifteenth resistor.

[0032] In an alternative embodiment, the output circuit includes a thirteenth switching transistor, a fourteenth switching transistor, a fifteenth switching transistor, an eighteenth resistor, and a nineteenth resistor; the thirteenth switching transistor, the fourteenth switching transistor, and the fifteenth switching transistor form a current mirror structure;

[0033] The power supply voltage terminal is grounded through the thirteenth switching transistor and the eighth resistor in sequence; the power supply voltage terminal is also connected to the input terminal of the twelfth switching transistor through the fourteenth switching transistor; the power supply voltage terminal is also grounded through the fifteenth switching transistor, the eighteenth resistor, and the nineteenth resistor in sequence; the control terminal of the eleventh switching transistor is connected between the eighteenth resistor and the nineteenth resistor;

[0034] The output circuit further includes a voltage output terminal, and the power supply voltage terminal is connected to the voltage output terminal through the fifteenth switching transistor; the voltage output terminal is used to output the output voltage of the power supply circuit.

[0035] In an alternative embodiment, the thirteenth switching transistor, the fourteenth switching transistor, and the fifteenth switching transistor form a 1:A:B current mirror structure.

[0036] In an alternative embodiment, the power supply circuit further includes an isolation circuit; the isolation circuit includes a sixteenth switching transistor, a ninth resistor, a sixteenth resistor, and an eleventh controllable current source;

[0037] The power supply voltage terminal is grounded through the thirteenth switching transistor, the eleventh controllable current source, and the eighth resistor in sequence; the positive control terminal of the eleventh controllable current source is connected to the voltage output terminal; the negative control terminal of the eleventh controllable current source is grounded through the ninth resistor; the positive control terminal of the eleventh controllable current source is also connected to the negative control terminal of the eleventh controllable current source through the sixteenth resistor;

[0038] The power supply voltage terminal is also connected to the input terminal of the twelfth switching transistor through the fourteenth switching transistor and the sixteenth switching transistor in sequence; the control terminal of the sixteenth switching transistor is connected to the first voltage terminal.

[0039] The technical solution provided by this application may include the following beneficial effects:

[0040] A power supply circuit with controllable output power provided by the present application, by setting circuit structures such as a power control circuit, when the input voltage VIN of the power supply circuit is relatively large, the output power of the power supply circuit can be appropriately reduced, so that the switching transistor in the output circuit arranged between the input voltage VIN and the output voltage VOUT can adopt a low-power switching transistor, and it is ensured that the switching transistor will not be damaged, thereby reducing the volume of the power supply circuit and improving the safety and reliability of the power supply circuit.

[0041] A power supply circuit with controllable output power provided by the present application, through a special circuit design, can ensure that after the power supply circuit enters a stable state, the current and voltage of each path in the voltage control circuit are exactly matched, and the gate voltage of the eleventh switching transistor M11 is exactly equal to the second voltage. At the same time, it can ensure that when the power supply circuit is at the control conversion point of the power control circuit, the gate voltage of the seventh switching transistor M7 is exactly equal to the third voltage. Therefore, a power supply circuit with controllable output power in the present application can improve the accuracy of the output voltage VOUT and the accuracy of the control conversion point of the power control circuit, thereby improving the safety and reliability of the output power control.

[0042] A power supply circuit with controllable output power provided by the present application, by setting an isolation circuit, enables the components below the isolation circuit to all adopt low-voltage components, thereby reducing the volume of the circuit; and, this isolation circuit makes the disturbance of the input voltage VIN not conduct to one end of the eighth resistor R8, thereby ensuring that the control conversion point of the power control circuit will not drift, and improving the safety and reliability of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 shows the power supply circuit in the related art;

[0045] Figure 2 is a schematic structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention;

[0046] Figure 3 is a schematic structural diagram of another power supply circuit with controllable output power according to an embodiment of the present invention;

[0047] Figure 4 is a relationship diagram between the maximum output power and the input voltage according to an embodiment of the present invention;

[0048] Figure 5 It is a schematic structural diagram of another power supply circuit with controllable output power according to an embodiment of the present invention. Specific embodiments

[0049] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0051] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0052] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0053] Figure 2 It is a schematic structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention. As Figure 2 shown, in this power supply circuit, it includes a voltage dividing circuit, a current source circuit, a power control circuit, a voltage control circuit, and an output circuit;

[0054] The voltage dividing circuit is electrically connected to the power supply voltage terminal and is used for dividing the input voltage of the power supply voltage terminal; the voltage dividing circuit is also electrically connected to the power control circuit and is used for outputting a corresponding divided voltage to the power control circuit according to the input voltage;

[0055] The current source circuit is electrically connected to the first voltage terminal and is used to supply power to the power control circuit and the voltage control circuit according to the first voltage of the first voltage terminal;

[0056] The input terminal of the output circuit is electrically connected to the supply voltage terminal; the output circuit is used to output the output voltage of the power supply circuit; the output circuit is electrically connected to the voltage control circuit;

[0057] The voltage control circuit is electrically connected to the second voltage terminal and is used to limit the output voltage to the output threshold voltage according to the second voltage of the second voltage terminal;

[0058] The power control circuit is electrically connected to the third voltage terminal and is used to control the output power of the power supply circuit according to the third voltage of the third voltage terminal and the input voltage, in combination with the voltage control circuit; when the input voltage does not exceed the power control threshold voltage, the power control circuit is used to limit the output power to the threshold power, and when the input voltage is higher than the power control threshold voltage, the output power is limited to be less than the threshold power and is inversely related to the input voltage.

[0059] Figure 2 The working principle of the shown power supply circuit with controllable output power is as follows:

[0060] After the circuit is powered on, that is, after the supply voltage terminal, the first voltage terminal, the second voltage terminal, and the third voltage terminal are powered, the input voltage of the power supply circuit is input to the voltage dividing circuit and the output circuit through the supply voltage terminal. The voltage dividing circuit divides the input voltage, and the current source circuit generates current according to the first voltage to supply power to the power control circuit and the voltage control circuit. The voltage control circuit limits the output voltage to the output threshold voltage according to the second voltage, so that after the power supply circuit is stabilized, the output voltage of the power supply circuit is equal to the output threshold voltage. Determine the threshold power according to the load demand of the power supply circuit, determine the power control threshold voltage based on the output threshold voltage, the threshold power, the input voltage, and the device parameters of the output circuit, and determine the device parameters in the voltage dividing circuit according to the power control threshold voltage.

[0061] Then, analyze according to the magnitude relationship between the input voltage and the power control threshold voltage:

[0062] When the input voltage is lower than the power control threshold voltage, the divided voltage output by the voltage dividing circuit to the power control circuit is 0. The power control circuit controls the output power of the power supply circuit according to the third voltage. When the output power of the power control circuit does not exceed the threshold power, the power supply circuit works normally. When the output power of the power control circuit is greater than the threshold power, the power control circuit pulls down the output power of the power supply circuit through the voltage control circuit.

[0063] When the input voltage is equal to the power threshold voltage, the output power of the power supply circuit is the maximum power that the devices in the output circuit can withstand. Thus, according to the load demand of the power supply circuit, the range of the output threshold voltage and output current can be obtained, and then the threshold power can be obtained. Then, the power control threshold voltage is determined based on the output threshold voltage, input voltage, threshold power, and the maximum power that the devices in the output circuit can withstand. And the device parameters in the voltage dividing circuit are determined according to the power control threshold voltage.

[0064] When the input voltage is higher than the power threshold voltage, the devices in the voltage dividing circuit break down and conduct, and the voltage dividing circuit outputs a voltage higher than 0 to the power control circuit. The power control circuit controls the output power of the power supply circuit according to the third voltage and the voltage divided by the voltage dividing circuit. The third voltage is the control conversion point, which is related to the output threshold voltage and threshold power, and is set based on the working principles of the output circuit and the power control circuit. The power control circuit limits the output power of the power supply circuit to not exceed the second threshold power based on the third voltage. The second threshold power is less than the threshold power PT and is inversely related to the voltage divided by the voltage dividing circuit. Since the voltage divided by the voltage dividing circuit is positively related to the input voltage, the second threshold power is inversely related to the input voltage. The larger the input voltage, the smaller the second threshold power, that is, the smaller the output power is limited. Thus, the switching tube in the output circuit arranged between the input voltage and the output voltage can use a low-power switching tube, and it is ensured that the switching tube will not be damaged, thereby reducing the volume and cost of the power supply circuit and improving the safety and reliability of the power supply circuit.

[0065] Figure 3 It is a schematic structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention.

[0066] In an optional implementation manner, the second voltage V2 is less than the first voltage V1; the third voltage V3 is less than the first voltage V1.

[0067] In an optional implementation manner, the voltage dividing circuit includes at least one voltage stabilizing diode, a first resistor R1, and a second resistor R2;

[0068] The power supply voltage terminal is grounded through at least one voltage stabilizing diode, the first resistor R1, and the second resistor R2 in sequence; the power supply voltage terminal is also connected to the power control circuit through at least one voltage stabilizing diode and the first resistor R1 in sequence. Attached Figure 3 Among them, GND represents grounding.

[0069] In an optional implementation manner, the current source circuit includes a first current source I1, a third resistor R3, a third controllable current source G3, a fourth controllable current source G4, a fifth controllable current source G5, a sixth controllable current source G6, a seventh controllable current source G7, an eighth controllable current source G8, and a ninth controllable current source G9;

[0070] The first voltage terminal is grounded through a third resistor R3 and a first current source I1 in sequence; the first voltage terminal is also connected to a power control circuit through a third controllable current source G3; the first voltage terminal is also connected to the power control circuit through a fourth controllable current source G4; the first voltage terminal is also connected to the power control circuit through a fifth controllable current source G5; the first voltage terminal is also connected to the power control circuit through a sixth controllable current source G6; the first voltage terminal is also connected to the power control circuit through a seventh controllable current source G7; the first voltage terminal is also connected to a voltage control circuit through an eighth controllable current source G8; the first voltage terminal is also connected to the voltage control circuit through a ninth controllable current source G9;

[0071] The positive control terminals of the third controllable current source G3, the fourth controllable current source G4, the fifth controllable current source G5, the sixth controllable current source G6, the seventh controllable current source G7, the eighth controllable current source G8, and the ninth controllable current source G9 are connected to the first voltage terminal; the negative control terminals of the third controllable current source G3, the fourth controllable current source G4, the fifth controllable current source G5, the sixth controllable current source G6, the seventh controllable current source G7, the eighth controllable current source G8, and the ninth controllable current source G9 are connected between the third resistor R3 and the first current source I1.

[0072] In an alternative embodiment, the ratio of the current value of the fourth controllable current source G4 to the current value of the fifth controllable current source G5 is 1:1; the ratio of the current value of the sixth controllable current source G6 to the current value of the seventh controllable current source G7 is 2:1; the ratio of the current value of the eighth controllable current source G8 to the current value of the ninth controllable current source G9 is 2:1.

[0073] In an alternative embodiment, the power control circuit includes a first switching transistor M1, a second switching transistor M2, a third switching transistor M3, a fourth switching transistor M4, a fifth switching transistor M5, a sixth switching transistor M6, a seventh switching transistor M7, an eighth switching transistor M8, a ninth switching transistor M9, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a first controllable current source G1, and a second controllable current source G2;

[0074] The first voltage terminal is grounded through the third controllable current source G3, the first switching transistor M1, and the fourth resistor R4 in sequence; the control terminal of the first switching transistor M1 is connected to the divided voltage; the first voltage terminal is also grounded through the third controllable current source G3, the second switching transistor M2, and the fifth resistor R5 in sequence;

[0075] The first voltage terminal is also grounded successively through a fourth controllable current source G4, a third switching transistor M3, and a fourth resistor R4; the first voltage terminal is also grounded successively through a fifth controllable current source G5, a fourth switching transistor M4, and a fifth resistor R5; the control terminal of the third switching transistor M3 is connected to the control terminal of the fourth switching transistor M4; the control terminal of the third switching transistor M3 is also connected to the input terminal of the third switching transistor M3;

[0076] The first voltage terminal is also grounded successively through a sixth resistor R6, a fifth switching transistor M5, and a seventh resistor R7; the control terminal of the fifth switching transistor M5 is connected to the input terminal of the fourth switching transistor M4; the control terminal of the second switching transistor M2 is grounded through the seventh resistor R7;

[0077] The first voltage terminal is also grounded successively through a sixth controllable current source G6, a sixth switching transistor M6, and a tenth resistor R10; the control terminal of the sixth switching transistor M6 is connected to the third voltage terminal; the first voltage terminal is also grounded successively through a sixth controllable current source G6, a seventh switching transistor M7, and an eleventh resistor R11; the first voltage terminal is also connected to the control terminal of the seventh switching transistor M7 through a first controllable current source G1; the positive control terminal of the first controllable current source G1 is connected to the negative control terminal of the first controllable current source G1 through the sixth resistor R6;

[0078] The first voltage terminal is also grounded successively through a seventh controllable current source G7 and a second controllable current source G2; the positive control terminal of the second controllable current source G2 is connected to the negative control terminal of the second controllable current source G2 through the tenth resistor R10;

[0079] The first voltage terminal is also grounded successively through a twelfth resistor R12, an eighth switching transistor M8, and a thirteenth resistor R13; the control terminal of the eighth switching transistor M8 is connected between the seventh controllable current source G7 and the second controllable current source G2;

[0080] The control terminal of the ninth switching transistor M9 is connected to the output terminal of the eighth switching transistor M8; the input terminal of the ninth switching transistor M9 is connected to the voltage control circuit; the output terminal of the ninth switching transistor M9 is grounded.

[0081] In an alternative embodiment, the resistance value of the fourth resistor R4 is equal to the resistance value of the fifth resistor R5.

[0082] In an alternative embodiment, the first switching transistor M1, the second switching transistor M2, the sixth switching transistor M6, the seventh switching transistor M7, and the ninth switching transistor M9 are PMOS transistors; the third switching transistor M3, the fourth switching transistor M4, the fifth switching transistor M5, and the eighth switching transistor M8 are NMOS transistors.

[0083] In an alternative embodiment, the voltage control circuit includes a tenth switching transistor M10, an eleventh switching transistor M11, a twelfth switching transistor M12, a fourteenth resistor R14, a fifteenth resistor R15, a seventeenth resistor R17, and a tenth controllable current source G10;

[0084] The first voltage terminal is grounded sequentially through an eighth controllable current source G8, the tenth switching transistor M10, and the fourteenth resistor R14; the control terminal of the tenth switching transistor M10 is connected to the second voltage terminal; the first voltage terminal is also grounded sequentially through the eighth controllable current source G8, the eleventh switching transistor M11, and the fifteenth resistor R15; the control terminal of the eleventh switching transistor M11 is electrically connected to the output circuit;

[0085] The first voltage terminal is also grounded sequentially through a ninth controllable current source G9 and the tenth controllable current source G10; the positive control terminal of the tenth controllable current source G10 is connected to the negative control terminal of the tenth controllable current source G10 through the fourteenth resistor R14;

[0086] The control terminal of the twelfth switching transistor M12 is connected to the input terminal of the ninth switching transistor M9; the input terminal of the twelfth switching transistor M12 is electrically connected to the output circuit; the output terminal of the twelfth switching transistor M12 is grounded through the seventeenth resistor R17.

[0087] In an alternative embodiment, the tenth switching transistor M10 and the eleventh switching transistor M11 are PMOS transistors; the twelfth switching transistor M12 is an NMOS transistor.

[0088] In an alternative embodiment, the output circuit includes a thirteenth switching transistor M13, a fourteenth switching transistor M14, a fifteenth switching transistor M15, an eighteenth resistor R18, and a nineteenth resistor R19; the thirteenth switching transistor M13, the fourteenth switching transistor M14, and the fifteenth switching transistor M15 form a current mirror structure;

[0089] The power supply voltage terminal is grounded sequentially through the thirteenth switching transistor M13 and the eighth resistor R8; the power supply voltage terminal is also connected to the input terminal of the twelfth switching transistor M12 through the fourteenth switching transistor M14; the power supply voltage terminal is also grounded sequentially through the fifteenth switching transistor M15, the eighteenth resistor R18, and the nineteenth resistor R19; the control terminal of the eleventh switching transistor M11 is connected between the eighteenth resistor R18 and the nineteenth resistor R19;

[0090] The output circuit further includes a voltage output terminal, and the power supply voltage terminal is connected to the voltage output terminal through the fifteenth switching transistor M15; the voltage output terminal is used to output the output voltage of the power supply circuit.

[0091] In an alternative embodiment, the thirteenth switching transistor M13, the fourteenth switching transistor M14, and the fifteenth switching transistor M15 form a current mirror structure of 1:A:B.

[0092] In an alternative embodiment, the thirteenth switching transistor M13, the fourteenth switching transistor M14, and the fifteenth switching transistor M15 are PMOS transistors.

[0093] In an alternative embodiment, the conduction threshold voltages of the sixth switching transistor M6, the seventh switching transistor M7, the tenth switching transistor M10, and the eleventh switching transistor M11 are the same, denoted as VV.

[0094] In an alternative embodiment, the difference between the third voltage V3 and the first voltage V1 is greater than the conduction threshold voltage VV. The difference between the second voltage V2 and the first voltage V1 is greater than the conduction threshold voltage VV. It should be noted that the magnitude relationship between the second voltage V2 and the third voltage V3 is not limited and can be equal or unequal.

[0095] Figure 3 The working principle of the shown power supply circuit with controllable output power is as follows:

[0096] After the circuit is powered on, the input voltage VIN at the power supply voltage terminal, the first voltage V1 at the first voltage terminal, the second voltage V2 at the second voltage terminal, and the third voltage V3 at the third voltage terminal are input into the power supply circuit. A first current is generated in the first current source I1, and this first current flows through the third resistor R3, generating a voltage drop across the third resistor R3. This voltage drop causes corresponding controllable currents to be generated in the third controllable current source G3 to the ninth controllable current source G9.

[0097] At this time, the eighth controllable current raises the source voltages of the tenth switching transistor M10 and the eleventh switching transistor M11 to the first voltage V1, and the gate voltages of the tenth switching transistor M10 and the eleventh switching transistor M11 are respectively the second voltage V2 and the divided voltage of the output voltage VOUT of the power supply circuit. Since the second voltage V2 is less than the first voltage V1, and the difference between the second voltage V2 and the first voltage V1 is greater than the conduction threshold voltage of the switching transistor. At the same time, since the fifteenth switching transistor M15 is not conducting when the circuit is just powered on and the output voltage VOUT is 0, therefore, both the tenth switching transistor M10 and the eleventh switching transistor M11 are conducting, and currents flow through both the tenth switching transistor M10 and the fourteenth resistor R14. At this time, a tenth controllable current is generated in the tenth controllable current source G10, and the current coefficient of the tenth controllable current source G10 is designed to be 1. Therefore, it can be obtained at this time that the current flowing through the tenth switching transistor M10 = the current flowing through the fourteenth resistor R14 = the tenth controllable current. At this time, from the above analysis, it can be seen that the gate voltage of the tenth switching transistor M10 is greater than the gate voltage of the eleventh switching transistor M11. Therefore, the current flowing through the tenth switching transistor M10 is less than the current flowing through the eleventh switching transistor M11. Since the sum of the current flowing through the tenth switching transistor M10 and the current flowing through the eleventh switching transistor M11 is equal to the eighth controllable current, it can be obtained that the current flowing through the tenth switching transistor M10 is less than half of the eighth controllable current, and the ninth controllable current is equal to half of the eighth controllable current. The current flowing through the tenth switching transistor M10 is equal to the tenth controllable current. Therefore, the tenth controllable current is less than the ninth controllable current, the gate voltage of the twelfth switching transistor M12 is raised, and the twelfth switching transistor M12 conducts.

[0098] At this time, the gate voltages of the thirteenth switching transistor M13, the fourteenth switching transistor M14, and the fifteenth switching transistor M15 are pulled down through the twelfth switching transistor M12 and the seventeenth resistor R17, and the thirteenth switching transistor M13, the fourteenth switching transistor M14, and the fifteenth switching transistor M15 all conduct.

[0099] At this time, current flows through the eighteenth resistor R18 and the nineteenth resistor R19, and the gate voltage of the eleventh switching transistor M11 gradually increases. After that, when the gate voltage of the eleventh switching transistor M11 gradually increases to be greater than the second voltage V2, the gate-source voltage difference of the eleventh switching transistor M11 is greater than the gate-source voltage difference of the tenth switching transistor M10, and the current flowing through the eleventh switching transistor M11 is greater than the current flowing through the tenth switching transistor M10. Since the sum of the current flowing through the tenth switching transistor M10 and the current flowing through the eleventh switching transistor M11 is equal to the eighth controllable current, it can be obtained that the current flowing through the tenth switching transistor M10 is greater than half of the eighth controllable current, and the ninth controllable current is equal to half of the eighth controllable current. The current flowing through the tenth switching transistor M10 is equal to the tenth controllable current. Therefore, the tenth controllable current is greater than the ninth controllable current, the gate voltage of the twelfth switching transistor M12 is pulled down, the twelfth switching transistor M12 is turned off, the current flowing through the fourteenth switching transistor M14 and the fifteenth switching transistor M15 becomes 0, the gate voltage of the eleventh switching transistor M11 decreases, and the circuit enters the next cycle. Therefore, when the power supply circuit enters the stable state, the gate voltage of the eleventh switching transistor M11 is equal to the second voltage V2. Therefore, at this time, it can be obtained that the second voltage , the output voltage .

[0100] It can be seen from this that after the circuit is powered on and enters the stable state, the output voltage VOUT is stabilized at a fixed value related to the magnitude of the second voltage V2 , which is denoted as the output threshold voltage.

[0101] According to the above output threshold voltage, threshold power PT, the range of the input voltage VIN, and the maximum power value that the fifteenth switching transistor M15 can withstand, the power control threshold voltage VINT is determined. See the following analysis for details. At this time, according to the magnitude of the power control threshold voltage VINT, the number of voltage stabilizing diodes in the voltage dividing circuit is determined. Assuming the number of voltage stabilizing diodes is M, and the reverse breakdown voltage of a single voltage stabilizing diode is VZ, it can be obtained that the power control threshold voltage . It should be noted that when multiple voltage stabilizing diodes are set, the multiple voltage stabilizing diodes are connected in series,[[]] Figure 3 and the first voltage stabilizing diode D1 and the second voltage stabilizing diode D2 are taken as examples.

[0102] Specifically, according to the magnitude relationship between the input voltage VIN and the power control threshold voltage VINT, it is analyzed in three cases:[[]]

[0103] (1) When the input voltage VIN is lower than the power control threshold voltage VINT, the zener diode is not broken down, the gate of the first switching transistor M1 is grounded through the second resistor R2, and the first switching transistor M1 is in the conducting state. That is, at this time, the divided voltage output by the voltage dividing circuit to the power control circuit is 0. At the same time, the fourth controllable current generated in the fourth controllable current source G4 raises the gate voltages of the third switching transistor M3 and the fourth switching transistor M4, and the third switching transistor M3 and the fourth switching transistor M4 are turned on. At this time, if the fifth controllable current generated in the fifth controllable current source G5 raises the gate voltage of the fifth switching transistor M5 and the fifth switching transistor M5 is turned on, the current flowing through the fourth switching transistor M4 is less than the fifth controllable current. Since the fourth controllable current is equal to the fifth controllable current, therefore, combined with Figure 3It can be seen that the fourth controllable current = the fifth controllable current = the current flowing through the third switching transistor M3. That is, at this time, the current flowing through the fourth switching transistor M4 is less than the current flowing through the third switching transistor M3. At the same time, since the fifth switching transistor M5 is conducting, current flows through the seventh resistor R7, and the gate voltage of the second switching transistor M2 is pulled up. The gate-source voltage difference of the first switching transistor M1 is greater than the gate-source voltage difference of the second switching transistor M2. The current flowing through the second switching transistor M2 is less than the current flowing through the first switching transistor M1. Therefore, when the fourth resistor R4 and the fifth resistor R5 have equal resistance values, the terminal voltage of the fourth resistor R4 must be greater than the terminal voltage of the fifth resistor R5. That is, the source voltage of the third switching transistor M3 is greater than the source voltage of the fourth switching transistor M4. Therefore, the gate-source voltage difference of the third switching transistor M3 is less than the gate-source voltage difference of the fourth switching transistor M4, and the current flowing through the third switching transistor M3 switches to be less than the current flowing through the fourth switching transistor M4. That is, the fifth controllable current switches to be less than the current flowing through the fourth switching transistor M4, and the gate voltage of the fifth switching transistor M5 is pulled down, and the fifth switching transistor M5 is turned off. From this, it can be known that when the input voltage VIN is lower than the power control threshold voltage VINT, the fifth switching transistor M5 is always in the off state. Therefore, at this time, no current flows through the sixth resistor R6, and no first controllable current is generated in the first controllable current source G1. At the same time, when the power supply circuit generates the output voltage VOUT, since the thirteenth switching transistor M13 is conducting, current flows through the thirteenth switching transistor M13 and the eighth resistor R8, and the gate voltage of the seventh switching transistor M7 gradually increases. At this time, since the third voltage V3 is input to the gate of the sixth switching transistor M6, when the circuit is just powered on, the gate voltage of the sixth switching transistor M6 is greater than the gate voltage of the seventh switching transistor M7. At the same time, the sixth controllable current pulls up the source voltages of the sixth switching transistor M6 and the seventh switching transistor M7 to the first voltage V1. And since the third voltage V3 is less than the first voltage V1 and the difference between the third voltage V3 and the first voltage V1 is greater than the conduction threshold voltage of the switching transistor, the gate voltage of the seventh switching transistor M7 is less than the third voltage V3. Therefore, at this time, both the sixth switching transistor M6 and the seventh switching transistor M7 are conducting, and current flows through both the sixth switching transistor M6 and the tenth resistor R10. At this time, a second controllable current is generated in the second controllable current source G2, and the current coefficient of the second controllable current source G2 is designed to be 1. Therefore, at this time, it can be obtained that the current flowing through the sixth switching transistor M6 = the current flowing through the tenth resistor R10 = the second controllable current.At this time, from the above analysis, it can be known that the gate voltage of the sixth switching transistor M6 is greater than the gate voltage of the seventh switching transistor M7. Therefore, the current flowing through the sixth switching transistor M6 is less than the current flowing through the seventh switching transistor M7. Since the sum of the current flowing through the seventh switching transistor M7 and the current flowing through the sixth switching transistor M6 is equal to the sixth controllable current, it can be obtained that the current flowing through the sixth switching transistor M6 is less than half of the sixth controllable current. And the seventh controllable current is equal to half of the sixth controllable current, and the current flowing through the sixth switching transistor M6 is equal to the second controllable current. Therefore, the second controllable current is less than the seventh controllable current, the gate voltage of the eighth switching transistor M8 is pulled up, and the eighth switching transistor M8 is turned on. After the eighth switching transistor M8 is turned on, it pulls up the gate voltage of the ninth switching transistor M9, and the ninth switching transistor M9 is in the off state.

[0104] Combined with the above analysis, since almost all of the current flowing through the fifteenth switching transistor M15 flows into the load, and a very small part of the current flows into the eighteenth resistor R18 and the nineteenth resistor R19, it can be considered that the output current is the current flowing through the fifteenth switching transistor M15. Therefore, at this time, since the output power is lower than the threshold power PT, it can be considered that the current flowing through the fifteenth switching transistor M15 is less than .

[0105] Therefore, by setting the power control circuit, when the input voltage VIN is lower than the power control threshold voltage VINT and the output power is lower than the threshold power PT, the output voltage , and the output current is controlled to be less than ; when the input voltage VIN is lower than the power control threshold voltage VINT and the output power is higher than the threshold power PT, the output current is greater than , that is, at this time, the current I15 flowing through the fifteenth switching transistor M15 is greater than . Since the thirteenth switching transistor M13 and the fifteenth switching transistor M15 form a 1:B current mirror structure, the relationship between the current I15 flowing through the fifteenth switching transistor M15 and the current I13 flowing through the thirteenth switching transistor M13 is , and by pre-designing the resistance value of the eighth resistor R8, when the current flowing through the fifteenth switching transistor M15 is greater than , the current flowing through the thirteenth switching transistor M13 will cause the terminal voltage of the eighth resistor R8 (i.e., the gate voltage of the seventh switching transistor M7) to be greater than the third voltage V3 (from the above analysis, it can be obtained that ), so at this time, the gate voltage of the sixth switching transistor M6 is less than the gate voltage of the seventh switching transistor M7. Therefore, the current flowing through the sixth switching transistor M6 is greater than the current flowing through the seventh switching transistor M7. Since the sum of the current flowing through the seventh switching transistor M7 and the current flowing through the sixth switching transistor M6 is equal to the sixth controllable current, it can be obtained that the current flowing through the sixth switching transistor M6 is greater than half of the sixth controllable current, and the seventh controllable current is equal to half of the sixth controllable current. The current flowing through the sixth switching transistor M6 is equal to the second controllable current. Therefore, the second controllable current is greater than the seventh controllable current, and the gate voltage of the eighth switching transistor M8 is pulled down, and the eighth switching transistor M8 is turned off. At this time, the gate voltage of the ninth switching transistor M9 is pulled down through the thirteenth resistor R13, the ninth switching transistor M9 is turned on, the gate voltage of the twelfth switching transistor M12 is pulled down, and the twelfth switching transistor M12 is turned off, and the output power decreases. When the output power decreases to within the threshold power PT, the power supply circuit continues to achieve normal output. It can be seen from this that when the input voltage VIN is lower than the power control threshold voltage VINT, the power control circuit limits the output power of the power supply circuit within the threshold power PT.

[0106] (2) When the input voltage VIN is equal to the power control threshold voltage VINT, it can be obtained that the maximum power borne by the fifteenth switching transistor M15 at this time is , and this maximum power is the maximum power value that the fifteenth switching transistor M15 can withstand. Therefore, in a power supply circuit with controllable output power provided by the present application, first, according to the load requirements of the power supply circuit, the range of the output threshold voltage and the output current is obtained, so as to obtain the threshold power PT, and then the power control threshold voltage VINT is determined according to the output threshold voltage, the range of the input voltage VIN, the threshold power PT, and the maximum power value that the fifteenth switching transistor M15 can withstand.

[0107] (3) When the input voltage VIN is higher than the power control threshold voltage VINT, all the voltage-regulating diodes in the voltage-dividing circuit are reversely broken down and turned on. At this time, the gate voltage of the first switching transistor M1 It should be noted that the gate voltage VG of the first switching transistor M1 is the divided voltage output by the voltage dividing circuit to the power control circuit. At this time, as analyzed above, the fifth switching transistor M5 is in the off state. Therefore, the gate of the second switching transistor M2 is grounded through the seventh resistor R7. That is, at this time, the gate voltage of the second switching transistor M2 is less than the gate voltage of the first switching transistor M1, and the gate-source voltage difference of the second switching transistor M2 is greater than the gate-source voltage difference of the first switching transistor M1. Therefore, the current flowing through the second switching transistor M2 is greater than the current flowing through the first switching transistor M1. Also, since the fourth controllable current is equal to the fifth controllable current, when the fifth switching transistor M5 is in the off state, the current flowing through the third switching transistor M3 is equal to the current flowing through the fourth switching transistor M4. Therefore, at this time, it can be obtained that the current flowing into the fourth resistor R4 is less than the current flowing into the fifth resistor R5, and the terminal voltage of the fourth resistor R4 is less than the terminal voltage of the fifth resistor R5. That is, the source voltage of the third switching transistor M3 is less than the source voltage of the fourth switching transistor M4. Therefore, the gate-source voltage difference of the third switching transistor M3 is greater than the gate-source voltage difference of the fourth switching transistor M4, and the current flowing through the third switching transistor M3 is greater than the current flowing through the fourth switching transistor M4. That is, the fifth controllable current is greater than the current flowing through the fourth switching transistor M4, and the gate voltage of the fifth switching transistor M5 is pulled up, and the fifth switching transistor M5 is turned on. At this time, a current flows through the branch composed of the sixth resistor R6, the fifth switching transistor M5, and the seventh resistor R7, and the terminal voltage of the seventh resistor R7 gradually increases, that is, the gate voltage of the second switching transistor M2 gradually increases. When the gate voltage of the second switching transistor M2 increases to be greater than the gate voltage of the first switching transistor M1, the gate-source voltage difference of the second switching transistor M2 is less than the gate-source voltage difference of the first switching transistor M1. Therefore, the current flowing through the second switching transistor M2 is less than the current flowing through the first switching transistor M1.

[0108] At this time, as analyzed above, the current flowing through the third switching transistor M3 is greater than the current flowing through the fourth switching transistor M4. Therefore, the current flowing into the fourth resistor R4 is greater than the current flowing into the fifth resistor R5, and the terminal voltage of the fourth resistor R4 is greater than the terminal voltage of the fifth resistor R5. That is, the source voltage of the third switching transistor M3 is greater than the source voltage of the fourth switching transistor M4. Therefore, the gate-source voltage difference of the third switching transistor M3 is less than the gate-source voltage difference of the fourth switching transistor M4, and the current flowing through the third switching transistor M3 is switched to be less than the current flowing through the fourth switching transistor M4. Therefore, the fifth controllable current is switched to be less than the current flowing through the fourth switching transistor M4, the gate voltage of the fifth switching transistor M5 is pulled down, the fifth switching transistor M5 is turned off, and the gate voltage of the second switching transistor M2 gradually decreases.

[0109] Therefore, when the circuit is in a stable state, the gate voltage of the second switching transistor M2 is equal to the gate voltage VG of the first switching transistor M1. At this time, it can be obtained that the current flowing through the branch composed of the sixth resistor R6, the fifth switching transistor M5, and the seventh resistor R7 is equal to , and since there is a current flowing through the sixth resistor R6, a first controllable current is generated in the first controllable current source G1. After designing the current coefficient of the first controllable current source G1 to be 1, it can be obtained that the first controllable current is equal to , and this first controllable current flows into the eighth resistor R8, thereby raising the gate voltage of the seventh switching transistor M7.

[0110] At the same time, since the relationship between the current I15 flowing through the fifteenth switching transistor M15 and the current I13 flowing through the thirteenth switching transistor M13 is , so at this time, the current flowing into the eighth resistor R8 is . And combining the analysis in point (1), it can be known that the power control circuit will adjust the terminal voltage of the eighth resistor R8 (i.e., the gate voltage of the seventh switching transistor M7) to be equal to the third voltage V3. Therefore, when the input voltage VIN is higher than the power control threshold voltage VINT, the control conversion point of the power control circuit is , and it can be obtained that at this time .

[0111] From the above analysis, it can be seen that when the current flowing through the fifteenth switching transistor M15 is less than , that is, when the output power is less than , the gate voltage of the seventh switching transistor M7 is less than the third voltage V3, the ninth switching transistor M9 is in the off state, and the power supply circuit is in the normal output state; when the current flowing through the fifteenth switching transistor M15 is greater than , that is, when the output power is greater than , the gate voltage of the seventh switching transistor M7 is greater than the third voltage V3, the ninth switching transistor M9 conducts, pulling down the gate voltage of the twelfth switching transistor M12, the twelfth switching transistor M12 turns off, the output power decreases, and when the output power drops to or less, the power supply circuit continues to achieve normal output.

[0112] Figure 4 is the relationship diagram of the maximum output power and the input voltage according to the embodiment of the present invention. From the above analysis in points (1), (2), and (3), when the input voltage VIN is lower than the power control threshold voltage VINT, the output power is limited to PT; when the input voltage VIN is higher than the power control threshold voltage VINT, the output power is controlled to , and since the gate voltage of the first switching transistor M1 , therefore, the greater the input voltage VIN, the smaller the output power is limited, so that the switching transistor provided between the input voltage VIN and the output voltage VOUT can use a low-power switching transistor and ensure that the switching transistor will not be damaged.

[0113] In an alternative embodiment, the resistance value of the tenth resistor R10 is equal to that of the eleventh resistor R11. As can be seen from the above analysis, when the power supply circuit is at the control conversion point of the power control circuit, the current flowing through the sixth switching transistor M6 is equal to the current flowing through the seventh switching transistor M7. Therefore, at this time, an eleventh resistor R11 is provided in the branch of the seventh switching transistor M7, and the resistance value of the eleventh resistor R11 is designed to be equal to that of the tenth resistor R10. Thus, when the current flowing through the sixth switching transistor M6 is equal to the current flowing through the seventh switching transistor M7, the voltage drops across the tenth resistor R10 and the eleventh resistor R11 are the same. At this time, the drain voltages of the sixth switching transistor M6 and the seventh switching transistor M7 are exactly equal. Therefore, it can be obtained that when the current flowing through the sixth switching transistor M6 is equal to the current flowing through the seventh switching transistor M7 and the drain voltages of the sixth switching transistor M6 and the seventh switching transistor M7 are also exactly equal, the gate voltages of the sixth switching transistor M6 and the seventh switching transistor M7 must be exactly equal, thereby ensuring that when the power supply circuit is at the control conversion point of the power control circuit, the gate voltage of the seventh switching transistor M7 is precisely equal to the third voltage V3. Therefore, through the above structure, the accuracy of the control conversion point of the power control circuit can be improved, thereby enhancing the safety and reliability of the power control circuit.

[0114] In an alternative embodiment, the resistance value of the fourteenth resistor R14 is equal to that of the fifteenth resistor R15. From Figure 3 the circuit structure, when the power supply circuit enters the stable state, the current flowing through the tenth switching transistor M10 is equal to the current flowing through the eleventh switching transistor M11. Therefore, at this time, a fifteenth resistor R15 is provided in the branch of the eleventh switching transistor M11, and the resistance value of the fifteenth resistor R15 is designed to be equal to that of the fourteenth resistor R14. Then, when the current flowing through the tenth switching transistor M10 is equal to the current flowing through the eleventh switching transistor M11, the voltage drops across the fourteenth resistor R14 and the fifteenth resistor R15 are the same, making the drain voltages of the tenth switching transistor M10 and the eleventh switching transistor M11 exactly equal at this time. Thus, it can be obtained that when the current flowing through the tenth switching transistor M10 is equal to the current flowing through the eleventh switching transistor M11 and the drain voltages of the tenth switching transistor M10 and the eleventh switching transistor M11 are also exactly equal, the gate voltages of the tenth switching transistor M10 and the eleventh switching transistor M11 must be exactly equal, thereby ensuring that when the power supply circuit enters the stable state, the current and voltage of each path in the voltage control circuit are perfectly matched, and the gate voltage of the eleventh switching transistor M11 is precisely equal to the second voltage V2. Therefore, through the above structure, the accuracy of the output voltage VOUT can be improved.

[0115] Figure 5It is a schematic structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention. In an alternative embodiment, the power supply circuit further includes an isolation circuit; the isolation circuit includes a sixteenth switch tube M16, a ninth resistor R9, a sixteenth resistor R16, and an eleventh controllable current source G11; the power supply voltage terminal is grounded through a thirteenth switch tube M13, an eleventh controllable current source G11, and an eighth resistor R8 in sequence; the positive control terminal of the eleventh controllable current source G11 is connected to the voltage output terminal; the negative control terminal of the eleventh controllable current source G11 is grounded through the ninth resistor R9; the positive control terminal of the eleventh controllable current source G11 is also connected to the negative control terminal of the eleventh controllable current source G11 through the sixteenth resistor R16; the power supply voltage terminal is also connected to the input terminal of the twelfth switch tube M12 through the fourteenth switch tube M14 and the sixteenth switch tube M16 in sequence; the control terminal of the sixteenth switch tube M16 is connected to the first voltage terminal. In an alternative embodiment, the sixteenth switch tube M16 is an NMOS tube.

[0116] After the circuit is powered on, when the twelfth switch tube M12 is turned on, the source voltage of the sixteenth switch tube M16 is pulled down, and the gate voltage of the sixteenth switch tube M16 is pulled up by the first voltage V1, so the sixteenth switch tube M16 is turned on, and the gate voltages of the thirteenth switch tube M13, the fourteenth switch tube M14, and the fifteenth switch tube M15 are pulled down through the sixteenth switch tube M16, the twelfth switch tube M12, and the seventeenth resistor R17, and the thirteenth switch tube M13, the fourteenth switch tube M14, and the fifteenth switch tube M15 are all turned on. At the same time, when the power supply circuit generates an output voltage VOUT, a voltage drop occurs across the sixteenth resistor R16, and since the thirteenth switch tube M13 is in the on state, therefore, a current flows through the thirteenth switch tube M13, the eleventh controllable current source G11, and the eighth resistor R8, and the gate voltage of the seventh switch tube M7 gradually increases. The sixteenth switch tube M16 plays a role in isolating high voltage, enabling the components below the sixteenth switch tube M16 in the power supply circuit to all use low-voltage components, thereby reducing the volume of the circuit. At the same time, the current coefficient of the eleventh controllable current source G11 is designed to be a relatively large value, such that the eleventh controllable current generated by the eleventh controllable current source G11 according to the sixteenth resistor R16 is greater than the current I13 flowing through the thirteenth switch tube M13, that is, the current capacity of the eleventh controllable current source G11 is greater than the current capacity of the thirteenth switch tube M13. Therefore, when the power control circuit is operating, the current flowing through the branch composed of the thirteenth switch tube M13, the eleventh controllable current source G11, and the eighth resistor R8 is equal to the current I13, thus ensuring that the isolation circuit does not affect the operation of the power control circuit; and, due to the provision of this isolation circuit, the perturbation of the input voltage VIN will not be conducted to one end of the eighth resistor R8, thereby ensuring that the control conversion point of the power control circuit does not drift, and improving the safety and reliability of the power supply circuit.

[0117] In summary, for the power supply circuit with controllable output power provided in this application, by setting circuit structures such as a power control circuit, when the input voltage VIN of the power supply circuit is relatively large, the output power of the power supply circuit can be appropriately reduced, so that a low-power switching transistor can be used for the switching transistor arranged between the input voltage VIN and the output voltage VOUT, and it is ensured that this switching transistor will not be damaged, thereby reducing the volume of the power supply circuit and improving the safety and reliability of the power supply circuit.

[0118] For the power supply circuit with controllable output power provided in this application, through a special circuit design, it can be ensured that after the power supply circuit enters a stable state, the current and voltage of each path in the voltage control circuit are completely matched, and the gate voltage of the eleventh switching transistor M11 is exactly equal to the second voltage V2. At the same time, it can be ensured that when the power supply circuit is at the control conversion point of the power control circuit, the gate voltage of the seventh switching transistor M7 is exactly equal to the third voltage V3. Therefore, for the power supply circuit with controllable output power in this application, the accuracy of the output voltage VOUT and the accuracy of the control conversion point of the power control circuit can be improved, thereby improving the safety and reliability of the output power control.

[0119] For the power supply circuit with controllable output power provided in this application, by setting an isolation circuit, low-voltage devices can be used for the devices below the isolation circuit, thereby reducing the volume of the circuit; moreover, this isolation circuit prevents the disturbance of the input voltage VIN from being conducted to one end of the eighth resistor R8, thereby ensuring that the control conversion point of the power control circuit will not drift, and improving the safety and reliability of the power supply circuit.

[0120] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A power supply circuit with controllable output power, characterized in that: The power supply circuit includes a voltage divider circuit, a current source circuit, a power control circuit, a voltage control circuit and an output circuit; The voltage divider circuit is electrically connected to the power supply voltage terminal and is used to divide the input voltage of the power supply voltage terminal; the voltage divider circuit is also electrically connected to the power control circuit and is used to output a corresponding divided voltage to the power control circuit according to the input voltage; The current source circuit is electrically connected to the first voltage terminal, and is used to supply power to the power control circuit and the voltage control circuit according to the first voltage of the first voltage terminal; The input end of the output circuit is electrically connected to the power supply voltage end; the output circuit is used to output the output voltage of the power supply circuit; the output circuit is electrically connected to the voltage control circuit; The voltage control circuit is electrically connected to the second voltage terminal and is used to limit the output voltage to an output threshold voltage according to the second voltage of the second voltage terminal; The power control circuit is electrically connected to the third voltage terminal, and is used to control the output power of the power supply circuit in combination with the voltage control circuit according to the third voltage of the third voltage terminal and the input voltage; when the input voltage does not exceed the power control threshold voltage, the power control circuit is used to limit the output power to within the threshold power, and when the input voltage is higher than the power control threshold voltage, the output power is limited to less than the threshold power and is inversely correlated with the input voltage.

2. The power supply circuit according to claim 1, characterized in that: The second voltage is lower than the first voltage; and the third voltage is lower than the first voltage.

3. The power supply circuit according to claim 1, characterized in that: The voltage divider circuit includes at least one voltage regulator tube, a first resistor and a second resistor; The power supply voltage end is connected to ground through at least one voltage regulator tube, a first resistor and a second resistor in sequence; the power supply voltage end is also connected to the power control circuit through at least one voltage regulator tube and a first resistor in sequence.

4. The power supply circuit according to any one of claims 1 to 3, characterized in that: The current source circuit includes a first current source, a third resistor, a third controllable current source, a fourth controllable current source, a fifth controllable current source, a sixth controllable current source, a seventh controllable current source, an eighth controllable current source and a ninth controllable current source; The first voltage terminal is connected to the ground through the third resistor and the first current source in sequence; the first voltage terminal is also connected to the power control circuit through the third controllable current source; the first voltage terminal is also connected to the power control circuit through the fourth controllable current source; the first voltage terminal is also connected to the power control circuit through the fifth controllable current source; the first voltage terminal is also connected to the power control circuit through the sixth controllable current source; the first voltage terminal is also connected to the power control circuit through the seventh controllable current source; the first voltage terminal is also connected to the voltage control circuit through the eighth controllable current source; the first voltage terminal is also connected to the voltage control circuit through the ninth controllable current source; The positive control ends of the third controllable current source, the fourth controllable current source, the fifth controllable current source, the sixth controllable current source, the seventh controllable current source, the eighth controllable current source and the ninth controllable current source are connected to the first voltage end; the negative control ends of the third controllable current source, the fourth controllable current source, the fifth controllable current source, the sixth controllable current source, the seventh controllable current source, the eighth controllable current source and the ninth controllable current source are connected between the third resistor and the first current source.

5. The power supply circuit according to claim 4, characterized in that: The ratio of the current value of the fourth controllable current source to the current value of the fifth controllable current source is 1:1; the ratio of the current value of the sixth controllable current source to the current value of the seventh controllable current source is 2:1; the ratio of the current value of the eighth controllable current source to the current value of the ninth controllable current source is 2:

1.

6. The power supply circuit according to claim 4, characterized in that: The power control circuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a fifth switch tube, a sixth switch tube, a seventh switch tube, an eighth switch tube, a ninth switch tube, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a first controllable current source and a second controllable current source; The first voltage terminal is grounded through the third controllable current source, the first switch tube and the fourth resistor in sequence; the control end of the first switch tube is connected to the divided voltage; the first voltage terminal is also grounded through the third controllable current source, the second switch tube and the fifth resistor in sequence; The first voltage end is also connected to ground via a fourth controllable current source, a third switch tube and a fourth resistor in sequence; the first voltage end is also connected to ground via a fifth controllable current source, a fourth switch tube and a fifth resistor in sequence; the control end of the third switch tube is connected to the control end of the fourth switch tube; the control end of the third switch tube is also connected to the input end of the third switch tube; The first voltage terminal is also connected to the ground through the sixth resistor, the fifth switch tube and the seventh resistor in sequence; the control terminal of the fifth switch tube is connected to the input terminal of the fourth switch tube; the control terminal of the second switch tube is connected to the ground through the seventh resistor; The first voltage terminal is also connected to ground through the sixth controllable current source, the sixth switch tube and the tenth resistor in sequence; the control end of the sixth switch tube is connected to the third voltage terminal; the first voltage terminal is also connected to ground through the sixth controllable current source, the seventh switch tube and the eleventh resistor in sequence; the first voltage terminal is also connected to the control end of the seventh switch tube through the first controllable current source; the positive control end of the first controllable current source is connected to the negative control end of the first controllable current source through the sixth resistor; The first voltage terminal is also grounded through the seventh controllable current source and the second controllable current source in sequence; the positive control terminal of the second controllable current source is connected to the negative control terminal of the second controllable current source through the tenth resistor; The first voltage terminal is also grounded through a twelfth resistor, an eighth switch tube and a thirteenth resistor in sequence; the control end of the eighth switch tube is connected between the seventh controllable current source and the second controllable current source; The control end of the ninth switch tube is connected to the output end of the eighth switch tube; the input end of the ninth switch tube is connected to the voltage control circuit; and the output end of the ninth switch tube is grounded.

7. The power supply circuit according to claim 6, characterized in that: The resistance value of the fourth resistor is equal to the resistance value of the fifth resistor; the resistance value of the tenth resistor is equal to the resistance value of the eleventh resistor.

8. The power supply circuit according to claim 6, characterized in that: The voltage control circuit includes a tenth switch tube, an eleventh switch tube, a twelfth switch tube, a fourteenth resistor, a fifteenth resistor, a seventeenth resistor and a tenth controllable current source; The first voltage terminal is connected to ground through an eighth controllable current source, a tenth switch tube and a fourteenth resistor in sequence; the control terminal of the tenth switch tube is connected to the second voltage terminal; the first voltage terminal is also connected to ground through an eighth controllable current source, an eleventh switch tube and a fifteenth resistor in sequence; the control terminal of the eleventh switch tube is electrically connected to the output circuit; The first voltage terminal is also grounded through a ninth controllable current source and a tenth controllable current source in sequence; the positive control terminal of the tenth controllable current source is connected to the negative control terminal of the tenth controllable current source through a fourteenth resistor; The control end of the twelfth switch tube is connected to the input end of the ninth switch tube; the input end of the twelfth switch tube is electrically connected to the output circuit; and the output end of the twelfth switch tube is grounded through a seventeenth resistor.

9. The power supply circuit according to claim 8, characterized in that: The resistance value of the fourteenth resistor is equal to the resistance value of the fifteenth resistor.

10. The power supply circuit according to claim 8, characterized in that: The output circuit includes a thirteenth switch tube, a fourteenth switch tube, a fifteenth switch tube, an eighteenth resistor and a nineteenth resistor; the thirteenth switch tube, the fourteenth switch tube and the fifteenth switch tube form a current mirror structure; The power supply voltage terminal is connected to the ground through the thirteenth switch tube and the eighth resistor in sequence; the power supply voltage terminal is also connected to the input end of the twelfth switch tube through the fourteenth switch tube; the power supply voltage terminal is also connected to the ground through the fifteenth switch tube, the eighteenth resistor and the nineteenth resistor in sequence; the control end of the eleventh switch tube is connected between the eighteenth resistor and the nineteenth resistor; The output circuit also includes a voltage output terminal, and the power supply voltage terminal is connected to the voltage output terminal through the fifteenth switch tube; the voltage output terminal is used to output the output voltage of the power supply circuit.

11. The power supply circuit according to claim 10, characterized in that: The thirteenth switch tube, the fourteenth switch tube and the fifteenth switch tube form a current mirror structure of 1:A:B.

12. The power supply circuit according to claim 10, characterized in that: The power supply circuit further includes an isolation circuit; the isolation circuit includes a sixteenth switch tube, a ninth resistor, a sixteenth resistor and an eleventh controllable current source; The supply voltage terminal is connected to ground through the thirteenth switch tube, the eleventh controllable current source and the eighth resistor in sequence; the positive control terminal of the eleventh controllable current source is connected to the voltage output terminal; the negative control terminal of the eleventh controllable current source is connected to ground through the ninth resistor; the positive control terminal of the eleventh controllable current source is also connected to the negative control terminal of the eleventh controllable current source through the sixteenth resistor; The power supply voltage end is also connected to the input end of the twelfth switch tube through the fourteenth switch tube and the sixteenth switch tube in sequence; the control end of the sixteenth switch tube is connected to the first voltage end.

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