Power supply circuit with controllable output power

Abstract

The invention relates to the technical field of circuit power supply, and discloses a power supply circuit with controllable output power. The power supply circuit comprises 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 for outputting corresponding divided voltage to the power control circuit according to the input voltage; the current source circuit is used for supplying power to the power control circuit and the voltage control circuit; the output circuit is used for outputting the output voltage of the power circuit; the voltage control circuit is used for limiting the output voltage at an output threshold voltage; the power control circuit is configured to control an output power of the power supply circuit, limit the output power to a threshold power when the input voltage does not exceed a power control threshold voltage, and limit the output power to be less than the threshold power and inversely correlated with the input voltage when the input voltage is higher than the power control threshold voltage. According to the circuit, the size of the power supply circuit is reduced, and the safety and reliability of the power supply circuit are improved.

Description

Technical Field

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

[0002] Figure 1 FIG. 2 shows a power supply circuit in the related art. Figure 1 As shown in FIG. 1 , in order to expand the application range of the power circuit, the input voltage VIN of the power circuit inside the chip is usually designed to be a wide-range voltage, that is, the power circuit in the related art can achieve a wide range of voltage input. Figure 1 It can be seen that the output voltage VOUT always maintains a fixed value related to the voltage VF under the joint action of the first feedback resistor RF1, the second feedback resistor RF2, the MOS tube MP and the controller U1. Therefore, at this time, if the output power remains unchanged, that is, the output current is always a fixed value, this will cause the voltage difference between the two ends of the MOS tube MP to be larger when the input voltage VIN is larger, so that the MOS tube MP needs to withstand a larger power.

[0003] Therefore, in order to make the MOS tube MP able to withstand the high power, the power circuit in the related art usually adopts a high-power MOS tube, which greatly increases the volume and cost of the power circuit. 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 very easy to cause the MOS tube MP to be damaged 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 the switch tube in the output circuit between the input voltage and the output voltage can use a low-power switch tube, and ensure that the switch tube 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: Provided is a power supply circuit with controllable output power, the power supply circuit comprising 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 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.

[0005] In an optional implementation, the second voltage is lower than the first voltage; and the third voltage is lower than the first voltage.

[0006] In an optional implementation, 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.

[0007] In an optional implementation, 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.

[0008] In an optional 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.

[0009] In an optional implementation, 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.

[0010] In an optional implementation, 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.

[0011] In an optional implementation, 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.

[0012] In an optional implementation, the resistance of the fourteenth resistor is equal to the resistance of the fifteenth resistor.

[0013] In an optional implementation, 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.

[0014] In an optional implementation, the thirteenth switch tube, the fourteenth switch tube and the fifteenth switch tube form a 1:A:B current mirror structure.

[0015] In an optional implementation, 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.

[0016] The technical solution provided by this application may have the following beneficial effects: The present application provides a power supply circuit with controllable output power. By setting circuit structures such as a power control circuit, when the input voltage VIN of the power supply circuit is large, the output power of the power supply circuit can be appropriately reduced, so that a switch tube in the output circuit set between the input voltage VIN and the output voltage VOUT can use a small-power switch tube and ensure that the switch tube will not be damaged, thereby reducing the volume of the power supply circuit and improving the safety and reliability of the power supply circuit.

[0017] The present application provides a power supply circuit with controllable output power. Through a special circuit design, it can be ensured that when the power supply circuit enters a stable state, the current voltages of various paths in the voltage control circuit are completely matched, and the gate voltage of the eleventh switch tube M11 is precisely equal to the second voltage. At the same time, it can be ensured that when the power supply circuit is at the control transition point of the power control circuit, the gate voltage of the seventh switch tube M7 is precisely equal to the third voltage. Therefore, the 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 transition point of the power control circuit, thereby improving the safety and reliability of the output power control.

[0018] The present application provides a power supply circuit with controllable output power. By setting an isolation circuit, all devices below the isolation circuit can adopt low-voltage devices, thereby reducing the volume of the circuit; and the isolation circuit prevents the disturbance of the input voltage VIN from being transmitted to one end of the eighth resistor R8, thereby ensuring that the control switching point of the power control circuit will not drift, thereby improving the safety and reliability of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A power supply circuit in the related art is shown; Figure 2 is a schematic structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention; Figure 3 is a schematic structural diagram of another power supply circuit with controllable output power according to an embodiment of the present invention; Figure 4 is a graph showing the relationship between the maximum output power and the input voltage according to an embodiment of the present invention; Figure 5 4 is a schematic diagram of the structure of another power supply circuit with controllable output power according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Figure 2 FIG. 1 is a schematic diagram of a power supply circuit with controllable output power according to an embodiment of the present invention. Figure 2 As shown, 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 a second voltage at 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 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.

[0026] Figure 2 The working principle of the output power controllable power supply circuit shown is as follows: After the circuit is powered on, that is, after the power 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 into the voltage divider circuit and the output circuit through the power supply voltage terminal, the voltage divider circuit divides the input voltage, and the current source circuit generates a 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 stable, the output voltage of the power supply circuit is equal to the output threshold voltage. The threshold power is determined according to the load demand of the power supply circuit, the power control threshold voltage is determined based on the output threshold voltage, the threshold power, the input voltage, and the device parameters of the output circuit, and the device parameters in the voltage divider circuit are determined according to the power control threshold voltage.

[0027] Next, we analyze the relationship between the input voltage and the power control threshold voltage: When the input voltage is lower than the power control threshold voltage, the voltage divider circuit outputs a divided voltage to the power control circuit of 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 operates normally. When the output power of the power control circuit is greater than the threshold power, the power control circuit lowers the output power of the power supply circuit through the voltage control circuit.

[0028] 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. The range of the output threshold voltage and the output current can be obtained according to the load demand of the power supply circuit, thereby obtaining the threshold power. The power control threshold voltage is determined according to the output threshold voltage, the input voltage, the threshold power and the maximum power that the devices in the output circuit can withstand, and the device parameters in the voltage divider circuit are determined according to the power control threshold voltage.

[0029] When the input voltage is higher than the power threshold voltage, the device in the voltage divider circuit breaks down and conducts, and the voltage divider circuit outputs a voltage divider greater 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 divider voltage. The third voltage is a control switching point, which is related to the output threshold voltage and the threshold power, and is set based on the working principle of the output circuit and the power control circuit. The power control circuit limits the output power of the power supply circuit to no more than the second threshold power based on the third voltage. The second threshold power is less than the threshold power PT and is inversely correlated with the voltage divider. Since the voltage divider voltage is positively correlated with the input voltage, the second threshold power is inversely correlated with the input voltage. The larger the input voltage, the smaller the second threshold power, that is, the smaller the output power is limited, so that the switch tube in the output circuit set between the input voltage and the output voltage can use a small power switch tube, and ensure that the switch 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.

[0030] Figure 3 It is a structural schematic diagram of a power supply circuit with controllable output power according to an embodiment of the present invention.

[0031] In an optional implementation, the second voltage V2 is lower than the first voltage V1; and the third voltage V3 is lower than the first voltage V1.

[0032] In an optional implementation, the voltage divider circuit includes at least one voltage regulator tube, a first resistor R1 and a second resistor R2; The power supply voltage terminal is connected to the ground through at least one voltage regulator tube, a first resistor R1 and a second resistor R2 in sequence; the power supply voltage terminal is also connected to the power control circuit through at least one voltage regulator tube and the first resistor R1 in sequence. Figure 3In the diagram, GND indicates ground.

[0033] In an optional implementation, 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; The first voltage terminal is connected to the ground through the third resistor R3 and the first current source I1 in sequence; the first voltage terminal is also connected to the power control circuit through the third controllable current source G3; the first voltage terminal is also connected to the power control circuit through the fourth controllable current source G4; the first voltage terminal is also connected to the power control circuit through the fifth controllable current source G5; the first voltage terminal is also connected to the power control circuit through the sixth controllable current source G6; the first voltage terminal is also connected to the power control circuit through the seventh controllable current source G7; the first voltage terminal is also connected to the voltage control circuit through the eighth controllable current source G8; the first voltage terminal is also connected to the voltage control circuit through the ninth controllable current source G9; The positive control ends 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 end; the negative control ends 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.

[0034] In an optional 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.

[0035] In an optional implementation, the power control circuit includes a first switch tube M1, a second switch tube M2, a third switch tube M3, a fourth switch tube M4, a fifth switch tube M5, a sixth switch tube M6, a seventh switch tube M7, an eighth switch tube M8, a ninth switch tube 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; The first voltage terminal is grounded through the third controllable current source G3, the first switch tube M1 and the fourth resistor R4 in sequence; the control end of the first switch tube M1 is connected to the divided voltage; the first voltage terminal is also grounded through the third controllable current source G3, the second switch tube M2 and the fifth resistor R5 in sequence; The first voltage end is also connected to ground via the fourth controllable current source G4, the third switch tube M3 and the fourth resistor R4 in sequence; the first voltage end is also connected to ground via the fifth controllable current source G5, the fourth switch tube M4 and the fifth resistor R5 in sequence; the control end of the third switch tube M3 is connected to the control end of the fourth switch tube M4; the control end of the third switch tube M3 is also connected to the input end of the third switch tube M3; The first voltage terminal is also connected to the ground through the sixth resistor R6, the fifth switch tube M5 and the seventh resistor R7 in sequence; the control terminal of the fifth switch tube M5 is connected to the input terminal of the fourth switch tube M4; the control terminal of the second switch tube M2 is connected to the ground through the seventh resistor R7; The first voltage terminal is also connected to ground through the sixth controllable current source G6, the sixth switch tube M6 and the tenth resistor R10 in sequence; the control end of the sixth switch tube M6 is connected to the third voltage terminal; the first voltage terminal is also connected to ground through the sixth controllable current source G6, the seventh switch tube M7 and the eleventh resistor R11 in sequence; the first voltage terminal is also connected to the control end of the seventh switch tube M7 through the first controllable current source G1; the positive control end of the first controllable current source G1 is connected to the negative control end of the first controllable current source G1 through the sixth resistor R6; The first voltage terminal is also grounded through the seventh controllable current source G7 and the second controllable current source G2 in sequence; 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; The first voltage terminal is also grounded through the twelfth resistor R12, the eighth switch tube M8 and the thirteenth resistor R13 in sequence; the control end of the eighth switch tube M8 is connected between the seventh controllable current source G7 and the second controllable current source G2; The control end of the ninth switch tube M9 is connected to the output end of the eighth switch tube M8; the input end of the ninth switch tube M9 is connected to the voltage control circuit; and the output end of the ninth switch tube M9 is grounded.

[0036] In an optional implementation, the resistance of the fourth resistor R4 is equal to the resistance of the fifth resistor R5.

[0037] In an optional implementation, the first switch tube M1, the second switch tube M2, the sixth switch tube M6, the seventh switch tube M7, and the ninth switch tube M9 are PMOS tubes; the third switch tube M3, the fourth switch tube M4, the fifth switch tube M5, and the eighth switch tube M8 are NMOS tubes.

[0038] In an optional implementation, the voltage control circuit includes a tenth switch tube M10, an eleventh switch tube M11, a twelfth switch tube M12, a fourteenth resistor R14, a fifteenth resistor R15, a seventeenth resistor R17 and a tenth controllable current source G10; The first voltage terminal is grounded through the eighth controllable current source G8, the tenth switch tube M10 and the fourteenth resistor R14 in sequence; the control terminal of the tenth switch tube M10 is connected to the second voltage terminal; the first voltage terminal is also grounded through the eighth controllable current source G8, the eleventh switch tube M11 and the fifteenth resistor R15 in sequence; the control terminal of the eleventh switch tube M11 is electrically connected to the output circuit; The first voltage terminal is also grounded through the ninth controllable current source G9 and the tenth controllable current source G10 in sequence; 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; The control end of the twelfth switch tube M12 is connected to the input end of the ninth switch tube M9; the input end of the twelfth switch tube M12 is electrically connected to the output circuit; and the output end of the twelfth switch tube M12 is grounded through the seventeenth resistor R17.

[0039] In an optional implementation, the tenth switch tube M10 and the eleventh switch tube M11 are PMOS tubes; and the twelfth switch tube M12 is an NMOS tube.

[0040] In an optional implementation, the output circuit includes a thirteenth switch tube M13, a fourteenth switch tube M14, a fifteenth switch tube M15, an eighteenth resistor R18, and a nineteenth resistor R19; the thirteenth switch tube M13, the fourteenth switch tube M14, and the fifteenth switch tube M15 form a current mirror structure; The power supply voltage end is connected to the ground through the thirteenth switch tube M13 and the eighth resistor R8 in sequence; the power supply voltage end is also connected to the input end of the twelfth switch tube M12 through the fourteenth switch tube M14; the power supply voltage end is also connected to the ground through the fifteenth switch tube M15, the eighteenth resistor R18 and the nineteenth resistor R19 in sequence; the control end of the eleventh switch tube M11 is connected between the eighteenth resistor R18 and the nineteenth resistor R19; The output circuit also includes a voltage output terminal, and the supply voltage terminal is connected to the voltage output terminal through the fifteenth switch tube M15; the voltage output terminal is used to output the output voltage of the power supply circuit.

[0041] In an optional implementation, the thirteenth switch tube M13 , the fourteenth switch tube M14 , and the fifteenth switch tube M15 form a 1:A:B current mirror structure.

[0042] In an optional implementation, the thirteenth switch tube M13, the fourteenth switch tube M14 and the fifteenth switch tube M15 are PMOS tubes.

[0043] In an optional implementation, the sixth switch tube M6 , the seventh switch tube M7 , the tenth switch tube M10 , and the eleventh switch tube M11 have the same turn-on threshold voltage, which is denoted as VV.

[0044] In an optional implementation, the difference between the third voltage V3 and the first voltage V1 is greater than the on-threshold voltage VV. The difference between the second voltage V2 and the first voltage V1 is greater than the on-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.

[0045] Figure 3 The working principle of the output power controllable power supply circuit shown is as follows: After the circuit is powered on, the input voltage VIN of the power supply voltage end, the first voltage V1 of the first voltage end, the second voltage V2 of the second voltage end and the third voltage V3 of the third voltage end are input into the power supply circuit, and a first current is generated in the first current source I1. The first current flows through the third resistor R3, and a voltage drop is generated across the third resistor R3. The voltage drop causes the third controllable current source G3 to the ninth controllable current source G9 to generate corresponding controllable currents.

[0046] At this time, the eighth controllable current pulls up the source voltages of the tenth switch tube M10 and the eleventh switch tube M11 to the first voltage V1, and the gate voltages of the tenth switch tube M10 and the eleventh switch tube M11 are respectively the divided voltages of the second voltage V2 and 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 turn-on threshold voltage of the switch tube, and at the same time, since the fifteenth switch tube M15 is not turned on when the circuit is just powered on, the output voltage VOUT is 0, therefore, the tenth switch tube M10 and the eleventh switch tube M11 are both turned on, and current flows through the tenth switch tube M10 and the fourteenth resistor R14. At this time, the 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, so at this time, it can be obtained that the current flowing through the tenth switch tube M10=the current flowing through the fourteenth resistor R14=the tenth controllable current. At this time, it can be known from the above analysis that the gate voltage of the tenth switch tube M10 is greater than the gate voltage of the eleventh switch tube M11. Therefore, the current flowing through the tenth switch tube M10 is less than the current flowing through the eleventh switch tube M11. Since the sum of the current flowing through the tenth switch tube M10 and the current flowing through the eleventh switch tube M11 is equal to the eighth controllable current, it can be obtained that the current flowing through the tenth switch tube 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 switch tube M10 is equal to the tenth controllable current. Therefore, the tenth controllable current is less than the ninth controllable current, and the gate voltage of the twelfth switch tube M12 is pulled up, and the twelfth switch tube M12 is turned on.

[0047] At this time, 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 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.

[0048] At this time, current flows through the eighteenth resistor R18 and the nineteenth resistor R19, and the gate voltage of the eleventh switch tube M11 gradually increases. Afterwards, when the gate voltage of the eleventh switch tube M11 gradually increases to be greater than the second voltage V2, the gate-source voltage difference of the eleventh switch tube M11 is greater than the gate-source voltage difference of the tenth switch tube M10, and the current flowing through the eleventh switch tube M11 is greater than the current flowing through the tenth switch tube M10. Since the sum of the current flowing through the tenth switch tube M10 and the current flowing through the eleventh switch tube M11 is equal to the eighth switch tube M10, The current flowing through the tenth switch tube 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 switch tube 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 switch tube M12 is pulled down, the twelfth switch tube M12 is turned off, the current flowing through the fourteenth switch tube M14 and the fifteenth switch tube M15 becomes 0, the gate voltage of the eleventh switch tube M11 is reduced, and the circuit enters the next cycle. Therefore, when the power supply circuit enters a stable state, the gate voltage of the eleventh switch tube M11 is equal to the second voltage V2. Therefore, at this time, the second voltage , output voltage .

[0049] It can be seen that after the circuit is powered on and enters a stable state, the output voltage VOUT stabilizes at a fixed value related to the magnitude of the second voltage V2. , denoted as the output threshold voltage.

[0050] The power control threshold voltage VINT is determined according to the above output threshold voltage, threshold power PT, input voltage VIN and the maximum power value of the fifteenth switch tube M15. For details, see the analysis below. At this time, the number of voltage regulator tubes in the voltage divider circuit is determined according to the size of the power control threshold voltage VINT. Assuming that the number of voltage regulator tubes is M and the reverse breakdown voltage of a single voltage regulator tube is VZ, it can be obtained that the power control threshold voltage It should be noted that when multiple voltage regulator tubes are provided, the multiple voltage regulator tubes are connected in series. Figure 3 The first voltage regulator tube D1 and the second voltage regulator tube D2 are taken as examples.

[0051] Specifically, according to the relationship between the input voltage VIN and the power control threshold voltage VINT, the analysis is divided into three cases: (1) When the input voltage VIN is lower than the power control threshold voltage VINT, the voltage regulator tube is not broken down, the gate of the first switch tube M1 is grounded through the second resistor R2, and the first switch tube M1 is in the on state, that is, at this time, the divided voltage output by the voltage divider circuit to the power control circuit is 0. At the same time, the fourth controllable current generated in the fourth controllable current source G4 pulls up the gate voltage of the third switch tube M3 and the fourth switch tube M4, and the third switch tube M3 and the fourth switch tube M4 are turned on. At this time, if the fifth controllable current generated in the fifth controllable current source G5 pulls up the gate voltage of the fifth switch tube M5, and the fifth switch tube M5 is turned on, then the current flowing through the fourth switch tube 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 switch tube M3, that is, at this time, the current flowing through the fourth switch tube M4 is less than the current flowing through the third switch tube M3; at the same time, because the fifth switch tube M5 is turned on, the current flows through the seventh resistor R7, the gate voltage of the second switch tube M2 is pulled up, the gate-source voltage difference of the first switch tube M1 is greater than the gate-source voltage difference of the second switch tube M2, and the current flowing through the second switch tube M2 is less than the current flowing through the first switch tube 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 The gate voltage of the third switch tube M3 is greater than the terminal voltage of the fifth resistor R5, that is, the source voltage of the third switch tube M3 is greater than the source voltage of the fourth switch tube M4. Therefore, the gate-source voltage difference of the third switch tube M3 is less than the gate-source voltage difference of the fourth switch tube M4, and the current flowing through the third switch tube M3 is switched to be less than the current flowing through the fourth switch tube M4, that is, the fifth controllable current is switched to be less than the current flowing through the fourth switch tube M4, and the gate voltage of the fifth switch tube M5 is pulled down, and the fifth switch tube M5 is turned off. It can be seen that when the input voltage VIN is lower than the power control threshold voltage VINT, the fifth switch tube M5 is always in the off state. Therefore, at this time, no current flows through the sixth resistor R6, and the first controllable current source G1 does not generate the first controllable current. At the same time, after the power supply circuit generates the output voltage VOUT, since the thirteenth switch tube M13 is in the on state, the thirteenth switch tube M13 and the eighth resistor R8 flow through the current, and the gate voltage of the seventh switch tube M7 gradually increases. At this time, since the gate of the sixth switch tube M6 inputs the third voltage V3, when the circuit is just powered on, the gate voltage of the sixth switch tube M6 is greater than the gate voltage of the seventh switch tube M7. At the same time, the sixth controllable current pulls the source voltages of the sixth switch tube M6 and the seventh switch tube M7 up 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 switch tube, the gate voltage of the seventh switch tube M7 is less than the third voltage V3. Therefore, at this time, the sixth switch tube M6 and the seventh switch tube M7 are both turned on, and current flows through the sixth switch tube M6 and the tenth resistor R10. At this time, the 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, so at this time, it can be obtained that the current flowing through the sixth switch tube M6 = the current flowing through the tenth resistor R10 = the second controllable current.At this time, it can be known from the above analysis that the gate voltage of the sixth switch tube M6 is greater than the gate voltage of the seventh switch tube M7. Therefore, the current flowing through the sixth switch tube M6 is less than the current flowing through the seventh switch tube M7. Since the sum of the current flowing through the seventh switch tube M7 and the current flowing through the sixth switch tube M6 is equal to the sixth controllable current, it can be obtained that the current flowing through the sixth switch tube M6 is less 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 switch tube M6 is equal to the second controllable current. Therefore, the second controllable current is less than the seventh controllable current, and the gate voltage of the eighth switch tube M8 is pulled up, and the eighth switch tube M8 is turned on. After being turned on, the eighth switch tube M8 pulls up the gate voltage of the ninth switch tube M9, and the ninth switch tube M9 is in the off state.

[0052] Combined with the above analysis, it can be seen that since the current flowing through the fifteenth switch tube M15 almost all 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 switch tube 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 switch tube M15 is less than .

[0053] Therefore, the power control circuit can be set so that 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 , 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 switch tube M15 is greater than Since the thirteenth switch tube M13 and the fifteenth switch tube M15 form a 1:B current mirror structure, the relationship between the current I15 flowing through the fifteenth switch tube M15 and the current I13 flowing through the thirteenth switch tube M13 is: , and by designing the resistance value of the eighth resistor R8 in advance, when the current flowing through the fifteenth switch tube M15 is greater than When the current flowing through the thirteenth switch tube M13 causes the terminal voltage of the eighth resistor R8 (that is, the gate voltage of the seventh switch tube M7) to be greater than the third voltage V3 (according to the above analysis, it can be obtained that ), so at this time, the gate voltage of the sixth switch tube M6 is less than the gate voltage of the seventh switch tube M7, therefore, the current flowing through the sixth switch tube M6 is greater than the current flowing through the seventh switch tube M7, and since the sum of the current flowing through the seventh switch tube M7 and the current flowing through the sixth switch tube M6 is equal to the sixth controllable current, it can be obtained that the current flowing through the sixth switch tube M6 is greater 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 switch tube 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 switch tube M8 is pulled down, and the eighth switch tube M8 is turned off. At this time, the gate voltage of the ninth switch tube M9 is pulled down through the thirteenth resistor R13, the ninth switch tube M9 is turned on, and the gate voltage of the twelfth switch tube M12 is pulled down. The twelfth switch tube 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 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 to within the threshold power PT.

[0054] (2) When the input voltage VIN is equal to the power control threshold voltage VINT, the maximum power that the fifteenth switch tube M15 can withstand is , the maximum power is the maximum power-bearing value of the fifteenth switch tube M15. Therefore, in a power supply circuit with controllable output power provided by the present application, the range of the output threshold voltage and the output current is first obtained according to the load requirement of the power supply circuit, thereby obtaining 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-bearing value of the fifteenth switch tube M15.

[0055] (3) When the input voltage VIN is higher than the power control threshold voltage VINT, all the voltage regulators in the voltage divider circuit reversely break down and conduct. At this time, the gate voltage of the first switch tube M1 is . It should be noted that the gate voltage VG of the first switch tube M1 is the divided voltage output by the voltage divider circuit to the power control circuit. At this time, it can be seen from the above analysis that the fifth switch tube M5 is in the off state, so the gate of the second switch tube M2 is grounded through the seventh resistor R7, that is, at this time, the gate voltage of the second switch tube M2 is less than the gate voltage of the first switch tube M1, and the gate-source voltage difference of the second switch tube M2 is greater than the gate-source voltage difference of the first switch tube M1, so the current flowing through the second switch tube M2 is greater than the current flowing through the first switch tube M1. Since the fourth controllable current is equal to the fifth controllable current, when the fifth switch tube M5 is in the off state, the current flowing through the third switch tube M3 is equal to the current flowing through the fourth switch tube 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 switch tube M3 is less than the source voltage of the fourth switch tube M4. Therefore, the gate-source voltage difference of the third switch tube M3 is greater than the gate-source voltage difference of the fourth switch tube M4, and the current flowing through the third switch tube M3 is greater than the current flowing through the fourth switch tube M4, that is, the fifth controllable current is greater than the current flowing through the fourth switch tube M4, and the gate voltage of the fifth switch tube M5 is pulled up, and the fifth switch tube M5 is turned on. At this time, current flows through the branch consisting of the sixth resistor R6, the fifth switch tube 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 switch tube M2 gradually increases. When the gate voltage of the second switch tube M2 increases to be greater than the gate voltage of the first switch tube M1, the gate-source voltage difference of the second switch tube M2 is smaller than the gate-source voltage difference of the first switch tube M1. Therefore, the current flowing through the second switch tube M2 is smaller than the current flowing through the first switch tube M1.

[0056] At this time, it can be seen from the above analysis that the current flowing through the third switch tube M3 is greater than the current flowing through the fourth switch tube M4. Therefore, the current flowing into the fourth resistor R4 is greater than the current flowing into the fifth resistor R5. 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 switch tube M3 is greater than the source voltage of the fourth switch tube M4. Therefore, the gate-source voltage difference of the third switch tube M3 is smaller than the gate-source voltage difference of the fourth switch tube M4. The current flowing through the third switch tube M3 is switched to be smaller than the current flowing through the fourth switch tube M4. Therefore, the fifth controllable current is switched to be smaller than the current flowing through the fourth switch tube M4, the gate voltage of the fifth switch tube M5 is pulled down, the fifth switch tube M5 is turned off, and the gate voltage of the second switch tube M2 is gradually reduced.

[0057] Therefore, when the circuit is in a stable state, the gate voltage of the second switch tube M2 is equal to the gate voltage VG of the first switch tube M1. At this time, the current flowing through the branch consisting of the sixth resistor R6, the fifth switch tube M5 and the seventh resistor R7 is equal to , and because the sixth resistor R6 flows with current, the first controllable current source G1 generates a first controllable current. After the current coefficient of the first controllable current source G1 is designed to be 1, the first controllable current is equal to , the first controllable current flows into the eighth resistor R8, thereby increasing the gate voltage of the seventh switch tube M7.

[0058] At the same time, since the relationship between the current I15 flowing through the fifteenth switch tube M15 and the current I13 flowing through the thirteenth switch tube M13 is , so at this time, the current flowing into the eighth resistor R8 is Combining the analysis of point (1), it can be seen that the power control circuit will adjust the terminal voltage of the eighth resistor R8 (i.e., the gate voltage of the seventh switch tube 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 transition point of the power control circuit is , but now .

[0059] From the above analysis, it can be seen that when the current flowing through the fifteenth switch tube M15 is less than , that is, when the output power is less than When the gate voltage of the seventh switch tube M7 is less than the third voltage V3, the ninth switch tube M9 is in the off state, and the power circuit is in the normal output state; when the current flowing through the fifteenth switch tube M15 is greater than , that is, when the output power is greater than When the gate voltage of the seventh switch tube M7 is greater than the third voltage V3, the ninth switch tube M9 is turned on, lowering the gate voltage of the twelfth switch tube M12, and the twelfth switch tube M12 is turned off, and the output power decreases. When the output power drops to When the voltage is within the range of 0 to 1, the power circuit continues to achieve normal output.

[0060] Figure 4 is a graph showing the relationship between the maximum output power and the input voltage according to an embodiment of the present invention. From the analysis of points (1), (2) and (3) above, it can be seen that 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 because the gate voltage of the first switch tube M1 Therefore, the larger the input voltage VIN is, the smaller the output power is limited, so that the switch tube set between the input voltage VIN and the output voltage VOUT can use a small power switch tube and ensure that the switch tube will not be damaged.

[0061] In an optional implementation, the resistance of the tenth resistor R10 is equal to the resistance of the eleventh resistor R11. From the above analysis, it can be known that when the power supply circuit is at the control conversion point of the power control circuit, the current flowing through the sixth switch tube M6 is equal to the current flowing through the seventh switch tube M7. Therefore, at this time, the eleventh resistor R11 is set in the branch of the seventh switch tube M7, and the resistance value of the eleventh resistor R11 is designed to be equal to the resistance value of the tenth resistor R10. Therefore, when the current flowing through the sixth switch tube M6 is equal to the current flowing through the seventh switch tube M7, the voltage drop in the tenth resistor R10 and the eleventh resistor R11 are the same. At this time, the drain voltages of the sixth switch tube M6 and the seventh switch tube M7 are completely equal. Therefore, it can be obtained that when the current flowing through the sixth switch tube M6 is equal to the current flowing through the seventh switch tube M7, the drain voltages of the sixth switch tube M6 and the seventh switch tube M7 are also completely equal, and the gate voltages of the sixth switch tube M6 and the seventh switch tube M7 must be completely 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 switch tube M7 is accurately equal to the third voltage V3. Therefore, through the above structure, the accuracy of the control switching point of the power control circuit can be improved, thereby improving the safety and reliability of the power control circuit. In an optional implementation, the resistance of the fourteenth resistor R14 is equal to the resistance of the fifteenth resistor R15. Figure 3 It can be seen from the circuit structure that when the power supply circuit enters a stable state, the current flowing through the tenth switch tube M10 is equal to the current flowing through the eleventh switch tube M11. Therefore, at this time, a fifteenth resistor R15 is set in the branch of the eleventh switch tube M11, and the resistance value of the fifteenth resistor R15 is designed to be equal to the resistance value of the fourteenth resistor R14. Then, when the current flowing through the tenth switch tube M10 is equal to the current flowing through the eleventh switch tube M11, the voltage drop in the fourteenth resistor R14 and the fifteenth resistor R15 is the same, so that at this time, the tenth switch tube M10 is equal to the current flowing through the eleventh switch tube M11. The drain voltages of the tenth switch tube M10 and the eleventh switch tube M11 are completely equal, so it can be obtained that when the current flowing through the tenth switch tube M10 is equal to the current flowing through the eleventh switch tube M11, and the drain voltages of the tenth switch tube M10 and the eleventh switch tube M11 are also completely equal, the gate voltages of the tenth switch tube M10 and the eleventh switch tube M11 must be completely equal, thereby ensuring that when the power supply circuit enters a stable state, the current voltages of each path in the voltage control circuit are completely matched, and the gate voltage of the eleventh switch tube M11 is accurately equal to the second voltage V2. Therefore, through the above structure, the accuracy of the output voltage VOUT can be improved.

[0062] Figure 5It is a structural diagram of a power supply circuit with controllable output power according to an embodiment of the present invention. In an optional embodiment, the power supply circuit also 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 end is connected to the ground through the thirteenth switch tube M13, the eleventh controllable current source G11 and the eighth resistor R8 in sequence; the positive control end of the eleventh controllable current source G11 is connected to the voltage output end; the negative control end of the eleventh controllable current source G11 is connected to the ground through the ninth resistor R9; the positive control end of the eleventh controllable current source G11 is also connected to the negative control end of the eleventh controllable current source G11 through the sixteenth resistor R16; the power supply voltage end is also connected to the input end of the twelfth switch tube M12 through the fourteenth switch tube M14 and the sixteenth switch tube M16 in sequence; the control end of the sixteenth switch tube M16 is connected to the first voltage end. In an optional embodiment, the sixteenth switch tube M16 is an NMOS tube.

[0063] 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, 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, after the power supply circuit generates the output voltage VOUT, a voltage drop is generated across the sixteenth resistor R16, and because the thirteenth switch tube M13 is in the on state, 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, so that the devices below the sixteenth switch tube M16 in the power supply circuit can all use low-voltage devices, 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 larger value, so 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 working, 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, thereby ensuring that the isolation circuit will not affect the operation of the power control circuit; and, due to the provision of the isolation circuit, the disturbance of the input voltage VIN will not be transmitted to one end of the eighth resistor R8, thereby ensuring that the control conversion point of the power control circuit will not drift, thereby improving the safety and reliability of the power supply circuit.

[0064] To sum up, the present application provides a power supply circuit with controllable output power. By setting circuit structures such as a power control circuit, when the input voltage VIN of the power supply circuit is large, the output power of the power supply circuit can be appropriately reduced, so that the switch tube set between the input voltage VIN and the output voltage VOUT can adopt a small-power switch tube and ensure that the switch tube will not be damaged, thereby reducing the volume of the power supply circuit and improving the safety and reliability of the power supply circuit.

[0065] The present application provides a power supply circuit with controllable output power. Through a special circuit design, it can be ensured that when the power supply circuit enters a stable state, the current voltages of various paths in the voltage control circuit are completely matched, and the gate voltage of the eleventh switch tube M11 is precisely equal to the second voltage V2. At the same time, it can be ensured that when the power supply circuit is at the control transition point of the power control circuit, the gate voltage of the seventh switch tube M7 is precisely equal to the third voltage V3. Therefore, the 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 transition point of the power control circuit, thereby improving the safety and reliability of the output power control.

[0066] The present application provides a power supply circuit with controllable output power. By setting an isolation circuit, all devices below the isolation circuit can adopt low-voltage devices, thereby reducing the volume of the circuit; and the isolation circuit prevents the disturbance of the input voltage VIN from being transmitted to one end of the eighth resistor R8, thereby ensuring that the control switching point of the power control circuit will not drift, thereby improving the safety and reliability of the power supply circuit.

[0067] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled 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 list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the 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 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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