Power supply circuit, isolation power supply, chip and electronic equipment

Abstract

The invention provides a power supply circuit, an isolation power supply, a chip and electronic equipment. The power supply circuit comprises a boost converter. The boost converter can obtain the output voltage from the power tube group, carry out boost processing on the output voltage to obtain the power supply voltage, and transmit the power supply voltage to the secondary control circuit. The secondary control circuit can obtain the output voltage from the power tube set and generate the driving voltage according to the power supply voltage and the output voltage so as to drive the power tube set to be turned on or turned off. The power supply voltage is obtained by boosting the output voltage, so that the power supply voltage can be converted along with the conversion of the output voltage, and the power supply voltage is located in a higher voltage domain. Therefore, no matter whether the output voltage is large or small, the power supply voltage can meet the requirement of the driving voltage.

Description

Technical Field

[0001] The present application relates to the technical field of power management chips, and particularly to a power supply circuit, an isolated power supply, a chip, and an electronic device. Background Art

[0002] With the development of fast charging technology, fast charging adapters with high power, small size, and multiple output voltages have become a trend. In the field of existing fast charging adapters with multiple output voltages, a feasible solution is to add a switch tube group to each of the two output paths on the secondary side of the isolated power supply system. In this way, by controlling the on and off of these two switch tube groups, the adjustment of the two output voltages of the isolated power supply system is achieved, and the adjustment of these two output voltages does not affect each other. Among them, the isolated power supply system is a power supply with dual output voltages. The switch tube group is composed of a pair of switch tubes with parasitic diodes back to back.

[0003] Generally, the driving voltages of these two switch tube groups are generated by being powered by the power supply voltage of the secondary control unit in the isolated power supply system. However, since the two output voltages vary within a voltage range of, for example, 3.3V - 25V, that is to say, the two output voltages are variable, the driving voltages of these two switch tube groups change following the change of the two output voltages, resulting in that the power supply voltage of the secondary control unit cannot meet the requirements of the driving voltages of these two switch tube groups. Therefore, there is an urgent need for a power supply voltage output by a power supply circuit that can meet the requirements of the driving voltages of these two switch tube groups. Summary of the Invention

[0004] The present application provides a power supply circuit, an isolated power supply, a chip, and an electronic device, which can output a power supply voltage that meets the requirements of the driving voltage.

[0005] In a first aspect, the present application provides a power supply circuit, which is applied to an isolated power supply. The isolated power supply includes: a secondary control circuit and at least two output branches; the power supply circuit includes: a boost converter;

[0006] The input end of the boost converter is electrically connected to the first end of the power tube group in at least two output branches and the first input end of the secondary control circuit respectively, the output end of the boost converter is electrically connected to the second input end of the secondary control circuit, the output end of the secondary control circuit is electrically connected to the control end of the power tube group, and the second end of the power tube group is used to output the output voltage of the isolated power supply;

[0007] The boost converter is used to obtain the first voltage from the power tube group, boost the first voltage to obtain a power supply voltage, and transmit the power supply voltage to the secondary control circuit. The first voltage is used to represent the magnitude of the output voltage;

[0008] The secondary control circuit is configured to obtain the first voltage from the power transistor group, and generate a driving voltage according to the supply voltage and the first voltage, where the driving voltage is used to drive the power transistor group to turn on or off.

[0009] Through the power supply circuit provided by the first aspect, the boost converter can obtain the first voltage from the power transistor group, boost the first voltage to obtain the supply voltage, and transmit the supply voltage to the secondary control circuit. The secondary control circuit can obtain the first voltage from the power transistor group, and generate a driving voltage according to the supply voltage and the first voltage to drive the power transistor group to turn on or off. Since the supply voltage is obtained by boosting the first voltage used to characterize the magnitude of the output voltage, the supply voltage is in a higher voltage domain. Thus, regardless of whether the output voltage is a large voltage or a small voltage, the supply voltage can meet the requirements of the driving voltage.

[0010] In a possible design, the at least two output branches include: a first output branch and a second output branch. The first output branch includes a first power transistor group, and the second output branch includes a second power transistor group. The first voltage includes: a second voltage and a third voltage. The output voltage includes: a first output voltage and a second output voltage. The driving voltage includes: a first driving voltage and a second driving voltage. The second voltage is used to characterize the magnitude of the first output voltage, and the third voltage is used to characterize the magnitude of the second output voltage.

[0011] The first ends of the first power transistor group and the second power transistor group are both electrically connected to the input end of the boost converter. The control ends of the first power transistor group and the second power transistor group are both electrically connected to the output end of the secondary control circuit. The second end of the first power transistor group is used to output the first output voltage, and the second end of the second power transistor group is used to output the second output voltage.

[0012] The boost converter is specifically configured to obtain the second voltage from the first power transistor group, and obtain the third voltage from the second power transistor group, and use the maximum voltage of the second voltage and the third voltage as the input voltage of the boost converter.

[0013] The boost converter is further specifically configured to boost the input voltage to obtain the supply voltage, and transmit the supply voltage to the secondary control circuit.

[0014] The secondary control circuit is specifically configured to obtain the second voltage from the first power transistor group, and obtain the third voltage from the second power transistor group, generate the first driving voltage according to the supply voltage and the second voltage, and generate the second driving voltage according to the supply voltage and the third voltage.

[0015] In a possible design, the first power transistor group includes: a first power transistor and a second power transistor, and the second power transistor group includes: a third power transistor and a fourth power transistor;

[0016] The source electrodes of the first power transistor and the third power transistor are both electrically connected to the input terminal of the boost converter. The drain electrode of the first power transistor is electrically connected to the drain electrode of the second power transistor. The source electrode of the second power transistor is used to output the first output voltage. The drain electrode of the third power transistor is electrically connected to the drain electrode of the fourth power transistor. The source electrode of the fourth power transistor is used to output the second output voltage. The gate electrodes of the first power transistor, the second power transistor, the third power transistor, and the fourth power transistor are all electrically connected to the output terminal of the secondary control circuit.

[0017] In a possible design, the boost converter includes: an input voltage output circuit and a boost conversion circuit;

[0018] The input terminal of the input voltage output circuit is electrically connected to the first end of the power transistor group. The output terminal of the input voltage output circuit is electrically connected to the input terminal of the boost conversion circuit. The output terminal of the boost conversion circuit is electrically connected to the second input terminal of the secondary control circuit;

[0019] The input voltage output circuit is configured to obtain the second voltage from the first power transistor group, and obtain the third voltage from the second power transistor group, use the maximum voltage of the second voltage and the third voltage as the input voltage, and transmit the input voltage to the boost conversion circuit;

[0020] The boost conversion circuit is configured to perform a boost process on the input voltage to obtain the supply voltage.

[0021] In a possible design, the input voltage output circuit includes: a first diode and a first capacitor;

[0022] The positive electrode of the first diode is electrically connected to the first end of the power transistor group. The negative electrode of the first diode is electrically connected to the upper plate of the first capacitor. The lower plate of the first capacitor is electrically connected to the ground terminal of the isolated power supply. The input terminal of the boost conversion circuit is electrically connected between the negative electrode of the first diode and the upper plate of the first capacitor.

[0023] In a possible design, the boost conversion circuit includes: an inductor, a second capacitor, an upper transistor, and a lower transistor;

[0024] A first end of the inductor is electrically connected to an output end of the input voltage output circuit, a second end of the inductor is electrically connected to a first end of the upper transistor, a second end of the upper transistor is electrically connected to an upper plate of the second capacitor, a first end of the lower transistor is electrically connected between the second end of the inductor and the first end of the upper transistor, a second input end of the secondary control circuit is electrically connected between the second end of the upper transistor and the upper plate of the second capacitor, and a second end of the lower transistor and a lower plate of the second capacitor are both electrically connected to a ground end of the isolated power supply.

[0025] In a possible design, the lower transistor is a field effect transistor and the upper transistor is a freewheeling diode;

[0026] A control end of the lower transistor is electrically connected to the secondary control circuit;

[0027] The secondary control circuit is further configured to control turning on or off of the lower transistor.

[0028] In a possible design, the secondary control circuit includes: a power management circuit, a boost control circuit, and a voltage control circuit;

[0029] An output end of the boost converter is respectively electrically connected to a power supply end of the power management circuit, an input end of the boost control circuit, and a first input end of the voltage control circuit. A second input end of the voltage control circuit is electrically connected to a first end of the power transistor group. A first output end of the boost control circuit is electrically connected to a control end of the power management circuit. A second output end of the boost control circuit is electrically connected to a control end of the voltage control circuit. An output end of the voltage control circuit is electrically connected to a control end of the power transistor group;

[0030] The boost control circuit is configured to transmit an indication signal to the voltage control circuit when the supply voltage is greater than a preset voltage, where the indication signal is used to indicate the voltage control circuit to generate the drive voltage;

[0031] The voltage control circuit is configured to generate the drive voltage according to the supply voltage and the first voltage under the action of the indication signal;

[0032] The boost control circuit is further configured to transmit a control signal to the power management circuit when the supply voltage is greater than a preset voltage, where the control signal is used to control whether the supply voltage supplies power to the power management circuit;

[0033] The power management circuit is configured to use the supply voltage as the power supply voltage of the secondary control circuit under the action of the control signal.

[0034] In a second aspect, the present application provides an isolated power supply, which includes: a transformer, a secondary switching transistor, at least two output branches, an output capacitor, a secondary control circuit, and a power supply circuit in the first aspect and each possible design of the first aspect;

[0035] The non - common - name ends of the secondary winding of the transformer are respectively electrically connected to the first ends of the power transistor groups in the at least two output branches, the first input end of the secondary control circuit, and the input end of the power supply circuit. The control ends of the power transistor groups are electrically connected to the output end of the secondary control circuit. The second ends of the power transistor groups are electrically connected to the upper plate of the output capacitor. The common - name ends of the secondary winding of the transformer are respectively electrically connected to the drain of the secondary switching transistor and the first end of the secondary control circuit. The gate of the secondary switching transistor is electrically connected to the second end of the secondary control circuit. The source of the secondary switching transistor, the grounding end of the power supply circuit, and the lower plate of the output capacitor are all electrically connected to the grounding end of the isolated power supply. The output end of the power supply circuit is electrically connected to the second input end of the secondary control circuit.

[0036] For the isolated power supply provided in the second aspect and each possible design of the second aspect, the beneficial effects can refer to the beneficial effects brought by the first aspect and each possible implementation manner of the first aspect, which will not be elaborated here.

[0037] In a third aspect, the present application provides a chip, which includes: the power supply circuit in the first aspect and each possible design of the first aspect, or the isolated power supply in the second aspect.

[0038] In a fourth aspect, the present application provides an electronic device, which includes: the chip in the third aspect.

[0039] The above description is only an overview of the technical solutions of the embodiments of the present application. In order to be able to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the embodiments of the present application more obvious and understandable, the specific implementation manners of the present application are specifically listed below. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1 It is a schematic structural diagram of an isolated power supply system in the related art;

[0042] Figure 2 It is a schematic structural diagram of an isolated power supply provided by an embodiment of the present application;

[0043] Figure 3 It is a schematic structural diagram of a power supply circuit and a secondary control circuit in an isolated power supply provided by an embodiment of the present application. Specific embodiments

[0044] In the present application, "at least one" means one or more, and "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after. "At least one (item)" or its similar expression refers to any combination of these items, including any combination of single items or plural items. For example, at least one (item) of a alone, b alone, or c alone can represent: a alone, b alone, c alone, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0045] The orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application 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 a limitation to the present application.

[0046] The terms "connected" and "connection" should be understood in a broad sense. For example, the "connection" or "connection" of a circuit structure can refer not only to a physical connection, but also to an electrical connection or a signal connection. For example, it can be a direct connection, that is, a physical connection, or it can be indirectly connected through at least one intermediate element, as long as the circuit is connected. It can also be the connection inside two elements; the signal connection can refer not only to the signal connection through a circuit, but also to the signal connection through a media medium. For example, radio waves. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0047] Refer to Figure 1 , Figure 1It is a structural schematic diagram of an isolated power supply system in the related art. As Figure 1 shown, a switch tube group composed of switch tubes Q11' and Q12' is added to one output path, and another switch tube group composed of switch tubes Q21' and Q22' is added to another output path. In this way, by controlling the on and off of these two switch tube groups, the regulation of the two output voltages is achieved.

[0048] Since the two output voltages Vo1' and Vo2' are not fixed, the drive voltages S11' of switch tube Q11' and S12' of switch tube Q12' will also change with the change of output voltage Vo1', and the drive voltages S21' of switch tube Q21' and S22' of switch tube Q22' will also change with the change of output voltage Vo2'.

[0049] Generally, the drive voltages S11', S12', S21' and S22' are generated according to the power supply voltage of the secondary control unit. Since the power supply voltage of the secondary control unit is mainly to meet the requirement of the drive voltage S0' of the synchronous rectifier tube Q0' in the isolated power supply system. Therefore, the power supply voltage of the secondary control unit is small. Thus, the power supply voltage of the secondary control unit cannot meet the magnitude requirements of the drive voltages S11', S12', S21' and S22'. Especially when the output voltage Vo1' or Vo2' is large, the drive voltages S11', S12', S21' and S22' usually exceed the power supply voltage of the secondary control unit. Thus, the isolated power supply system cannot complete the control of the on and off of switch tubes Q11', Q12', Q21' and Q22'.

[0050] At the same time, the drive voltages S11', S12', S21' and S22' are in a floating ground state, that is to say, the drive voltages S11', S12', S21' and S22' are floating and changing relative to the ground potential, that is, zero voltage.

[0051] In addition, the secondary control unit usually uses the voltage SRD' for power supply. Since the voltage SRD is usually a high voltage of dozens of volts or even hundreds of volts. Therefore, the secondary control unit has disadvantages such as complex power supply circuit, large area and large power loss. Among them, the voltage SRD is obtained from the same-name end of the secondary winding of the transformer in the isolated power supply system.

[0052] To solve the above problems, the present application provides a power supply circuit, an isolated power supply, a chip and an electronic device.

[0053] Among them, the power supply circuit and the isolated power supply can be chips or circuit modules.

[0054] In addition, the power supply circuit and the isolated power supply can be integrated in one chip or in different chips, and the embodiments of the present application do not make specific limitations on this.

[0055] In the present application, the electronic device may include, but is not limited to: a power adapter, a power tool, a household appliance, and an electric vehicle charger.

[0056] Among them, the isolated power supply is, for example, a flyback converter (Flyback). For the sake of easy understanding, the embodiments of the present application will be described by taking the flyback converter Flyback as an example.

[0057] Referring to Figure 2 , Figure 2 is a schematic structural diagram of an isolated power supply provided by an embodiment of the present application. As Figure 2 shown, the isolated power supply 1000 may include: a transformer 400, a secondary switching transistor Q0, a power transistor group 300, an output capacitor 500, a secondary control circuit 200, and a power supply circuit 100.

[0058] The non - same - name ends of the secondary winding of the transformer 400 are respectively electrically connected to the first end of the power transistor group 300, the first input end of the secondary control circuit 200, and the input end of the power supply circuit 100. The control end of the power transistor group 300 is electrically connected to the output end of the secondary control circuit 200. The second end of the power transistor group 300 is electrically connected to the upper plate of the output capacitor 500. The same - name ends of the secondary winding of the transformer 400 are respectively electrically connected to the drain of the secondary switching transistor Q0 and the first end of the secondary control circuit 200. The gate of the secondary switching transistor Q0 is electrically connected to the second end of the secondary control circuit 200. The source of the secondary switching transistor Q0, the grounding end of the power supply circuit 100, and the lower plate of the output capacitor 500 are all electrically connected to the grounding end of the isolated power supply 1000. The output end of the power supply circuit 100 is electrically connected to the second input end of the secondary control circuit 200.

[0059] Among them, the secondary switching transistor Q0 may include, but is not limited to, a gallium nitride transistor, an insulated gate bipolar transistor, and a metal - oxide - semiconductor field - effect transistor.

[0060] Among them, the secondary switching transistor Q0 generally refers to a synchronous rectification control transistor.

[0061] The power supply circuit 100 can obtain a first voltage Vo_Pre for characterizing the output voltage of the isolated power supply 1000 from the first end of the power transistor group 300. That is to say, the power supply circuit 100 can draw power from the first end of the power transistor group 300. Moreover, the power supply circuit 100 can boost the first voltage Vo_Pre to obtain a supply voltage VBST and transmit the supply voltage VBST to the secondary control circuit 200, so that the secondary control circuit 200 can obtain the supply voltage VBST. In this way, the secondary control circuit 200 generates a driving voltage VDD_MID by using the power supply of the supply voltage VBST to drive the turning on and off of the power transistor group 300.

[0062] Referring to Figure 3 , Figure 3 is a schematic structural diagram of a power supply circuit and a secondary control circuit in an isolated power supply provided by an embodiment of the present application. As Figure 2 and Figure 3 shown, the power supply circuit 100 may include: a boost converter 100.

[0063] The input end of the boost converter 100 is electrically connected to the first end of the power transistor group 300 and the first input end of the secondary control circuit 200 respectively. The output end of the boost converter 100 is electrically connected to the second input end of the secondary control circuit 200. The output end of the secondary control circuit 200 is electrically connected to the control end of the power transistor group 300.

[0064] Figure 2 In , the first input end of the secondary control circuit 200 is denoted as 1, the second input end of the secondary control circuit 200 is denoted as 2, the output end of the secondary control circuit 200 is denoted as 3, the port for outputting the first driving voltage VDD_MID1 in the output end of the secondary control circuit 200 is denoted as 3-1, and the port for outputting the second driving voltage VDD_MID2 in the output end of the secondary control circuit 200 is denoted as 3-2.

[0065] The boost converter 100 can obtain the first voltage Vo_Pre from the power transistor group 300. Moreover, the boost converter 100 can boost the first voltage Vo_Pre to obtain a supply voltage VBST and transmit the supply voltage VBST to the secondary control circuit 200, so that the secondary control circuit 200 can obtain the supply voltage VBST.

[0066] Among them, since when the power transistor group 300 is turned on, the first voltage Vo_Pre is approximately equal to the output voltage. Therefore, the first voltage Vo_Pre is used to characterize the magnitude of the output voltage.

[0067] The secondary control circuit 200 can obtain the first voltage Vo_Pre from the power transistor group 300. And the secondary control circuit 200 can generate the driving voltage VDD_MID according to the supply voltage VBST and the first voltage Vo_Pre to turn on or off the power transistor group 300.

[0068] Among them, the driving voltage VDD_MID is used to turn on or off the power transistor group 300.

[0069] Exemplarily, when the power transistor group 300 is turned on, the driving voltage VDD_MID is the sum of the output voltage and the gate-source voltage Vgs. When the power transistor group 300 is turned off, the driving voltage VDD_MID is the output voltage. Among them, the gate-source voltage Vgs is the voltage that can ensure the complete turn-on of the power transistor group 300, that is to say, the gate-source voltage Vgs can make the power transistor group 300 in the linear region.

[0070] Since the supply voltage VBST is obtained by boosting the first voltage used to characterize the magnitude of the output voltage. Therefore, the supply voltage VBST is in a higher voltage domain. Thus, whether the output voltage is a large voltage or a small voltage, the supply voltage VBST can meet the requirements of the driving voltage VDD_MID.

[0071] For the power supply circuit provided in this application, the boost converter can obtain the first voltage from the power transistor group, boost the first voltage to obtain the supply voltage, and transmit the supply voltage to the secondary control circuit. The secondary control circuit can obtain the first voltage from the power transistor group and generate the driving voltage according to the supply voltage and the first voltage to drive the power transistor group to turn on or off. Since the supply voltage is obtained by boosting the first voltage used to characterize the magnitude of the output voltage, the supply voltage is in a higher voltage domain. Thus, whether the output voltage is a large voltage or a small voltage, the supply voltage can meet the requirements of the driving voltage.

[0072] In some examples, at least two output branches may include: a first output branch and a second output branch. The first output branch may include a first power transistor group 310, the second output branch may include a second power transistor group 320. The first voltage Vo_Pre may include: a second voltage Vo_Pre1 and a third voltage Vo_Pre2. The output voltage may include: a first output voltage Vo1 and a second output voltage Vo2. The driving voltage VDD_MID may include: a first driving voltage VDD_MID1 and a second driving voltage VDD_MID2.

[0073] The first end of the first power transistor group 310 and the first end of the second power transistor group 320 are both electrically connected to the input end of the boost converter 100. The control ends of the first power transistor group 310 and the second power transistor group 320 are both electrically connected to the output end of the secondary control circuit 200. The second end of the first power transistor group 310 is used to output the first output voltage Vo1, and the second end of the second power transistor group 320 is used to output the second output voltage Vo2.

[0074] Among them, the first end of the first power transistor group 310 and the first end of the second power transistor group 320 are both the first end of the power transistor group 300, and the control ends of the first power transistor group 310 and the second power transistor group 320 are both the control ends of the power transistor group 300.

[0075] The boost converter 100 can be used to obtain the second voltage Vo_Pre1 from the first power transistor group 310 and the third voltage Vo_Pre2 from the second power transistor group 320. Moreover, the boost converter 100 can use the maximum voltage among the second voltage Vo_Pre1 and the third voltage Vo_Pre2 as the input voltage Vin of the boost converter 100. That is to say, the boost converter 100 can use the maximum voltage among the first output voltage Vo1 and the second output voltage Vo2 as the input voltage Vin of the boost converter 100.

[0076] Among them, since when the first power transistor group 310 is turned on, the second voltage Vo_Pre1 is approximately equal to the first output voltage Vo1. Therefore, the second voltage Vo_Pre1 is used to characterize the magnitude of the first output voltage Vo1.

[0077] Among them, since when the second power transistor group 320 is turned on, the third voltage Vo_Pre2 is approximately equal to the second output voltage Vo2. Therefore, the third voltage Vo_Pre2 is used to characterize the magnitude of the second output voltage Vo2.

[0078] In this way, the boost converter 100 can boost the input voltage Vin to obtain the supply voltage VBST. Moreover, the boost converter 100 can transmit the supply voltage VBST to the secondary control circuit 200 so that the secondary control circuit 200 can obtain the supply voltage VBST.

[0079] The secondary control circuit 200 can obtain the second voltage Vo_Pre1 from the first power transistor group 310 and the third voltage Vo_Pre2 from the second power transistor group 320. Moreover, the secondary control circuit 200 can generate a first driving voltage VDD_MID1 according to the supply voltage VBST and the second voltage Vo_Pre1 to drive the first power transistor group 310 to turn on or off, and generate a second driving voltage VDD_MID2 according to the supply voltage VBST and the third voltage Vo_Pre2 to drive the second power transistor group 320 to turn on or off.

[0080] Since the boost converter 100 uses the maximum voltage among the first output voltage Vo1 and the second output voltage Vo2 as the input voltage Vin of the boost converter 100. Therefore, the conversion efficiency of the boost converter 100 can be improved, the working time of the boost converter 100 can be reduced, and the losses introduced during the operation of the boost converter 100 can be decreased.

[0081] Exemplarily, when the first power transistor group 310 is turned on, the first driving voltage VDD_MID1 is the sum of the first output voltage Vo1 and the first gate-source voltage Vgs1, that is, Vo1 + Vgs1. When the first power transistor group 310 is turned off, the first driving voltage VDD_MID1 is the first output voltage Vo1. Wherein, the first gate-source voltage Vgs1 is the voltage that can ensure the full turn-on of the first power transistor group 310. That is to say, the first gate-source voltage Vgs1 can make the first power transistor group 310 in the linear region.

[0082] Exemplarily, when the second power transistor group 320 is turned on, the second driving voltage VDD_MID2 is the sum of the second output voltage Vo2 and the second gate-source voltage Vgs2, that is, Vo2 + Vgs2. When the second power transistor group 320 is turned off, the second driving voltage VDD_MID2 is the second output voltage Vo2. Wherein, the second gate-source voltage Vgs2 is the voltage that can ensure the full turn-on of the second power transistor group 320. That is to say, the second gate-source voltage Vgs2 can make the second power transistor group 320 in the linear region.

[0083] In some examples, the first power transistor group 310 may include: a first power transistor Q11 and a second power transistor Q12.

[0084] The source of the first power transistor Q11 is electrically connected to the input terminal of the boost converter 100. The gates of the first power transistor Q11 and the second power transistor Q12 are both electrically connected to the output terminal of the secondary control circuit 200. The drain of the first power transistor Q11 is electrically connected to the drain of the second power transistor Q12. The source of the second power transistor Q12 is used to output the first output voltage Vo1.

[0085] Among them, the source of the first power transistor Q11 is the first end of the first power transistor group 310, the gates of the first power transistor Q11 and the second power transistor Q12 are both the control ends of the first power transistor group 310, and the source of the second power transistor Q12 is the second end of the first power transistor group 310.

[0086] Among them, the first power transistor Q11 and the second power transistor Q12 may include, but are not limited to, gallium nitride transistors, insulated gate bipolar transistors, and metal-oxide semiconductor field effect transistors.

[0087] Among them, the first gate-source voltage Vgs1 can ensure that the first power transistor Q11 and the second power transistor Q12 are fully turned on.

[0088] Among them, the first driving voltage for driving the first power transistor Q11 to turn on or off is denoted as VDD_MID11, and the first driving voltage for driving the second power transistor Q12 to turn on or off is denoted as VDD_MID12. The second driving voltage for driving the third power transistor Q21 to turn on or off is denoted as VDD_MID21, and the second driving voltage for driving the fourth power transistor Q22 to turn on or off is denoted as VDD_MID22.

[0089] In addition, the reference zero voltage of the first driving voltage VDD_MID11 for driving the first power transistor Q11 to turn on or off and the second driving voltage VDD_MID21 for driving the third power transistor Q21 to turn on or off is the first voltage Vo_Pre. The reference zero voltage of the first driving voltage VDD_MID12 for driving the second power transistor Q12 to turn on or off is the first output voltage Vo1. The reference zero voltage of the second driving voltage denoted as VDD_MID22 for driving the fourth power transistor Q22 to turn on or off is the second output voltage Vo2.

[0090] In some examples, the second power transistor group 320 may include: a third power transistor Q21 and a fourth power transistor Q22.

[0091] The source of the third power transistor Q21 is electrically connected to the input end of the boost converter 100, the gates of the third power transistor Q21 and the fourth power transistor Q22 are both electrically connected to the output end of the secondary control circuit 200, the drains of the third power transistor Q21 and the fourth power transistor Q22 are electrically connected, and the source of the fourth power transistor Q22 is used to output the second output voltage Vo2.

[0092] Among them, the source of the third power transistor Q21 is the first end of the second power transistor group 320, the gates of the third power transistor Q21 and the fourth power transistor Q22 are both the control ends of the second power transistor group 320, and the source of the fourth power transistor Q22 is the second end of the second power transistor group 320.

[0093] Among them, the third power transistor Q21 and the fourth power transistor Q22 may include, but are not limited to, gallium nitride transistors, insulated gate bipolar transistors, and metal-oxide semiconductor field effect transistors.

[0094] Among them, the second gate-source voltage Vgs2 can ensure that the third power transistor Q21 and the fourth power transistor Q22 are fully turned on.

[0095] Based on the description of the above embodiments, exemplarily, a possible implementation of the boost converter 100. As Figure 2 and Figure 3 shown, the boost converter 100 may include: an input voltage output circuit 110 and a boost conversion circuit 120.

[0096] The input end of the input voltage output circuit 110 is electrically connected to the first end of the power transistor group 300, the output end of the input voltage output circuit 110 is electrically connected to the input end of the boost conversion circuit 120, and the output end of the boost conversion circuit 120 is electrically connected to the second input end of the secondary control circuit 200.

[0097] Among them, the input voltage output circuit 110 and the boost conversion circuit 120 may be separately provided or integrated, and the embodiments of the present application do not make specific limitations thereon.

[0098] Among them, the input end of the input voltage output circuit 110 is the input end of the boost converter 100, and the output end of the boost conversion circuit 120 is the output end of the boost converter 100.

[0099] Figure 3 In, the power supply end of the power management circuit 210 is denoted as 1, the control end of the power management circuit 210 is denoted as 2, the input end of the boost control circuit 220 is denoted as 1, the first output end of the boost control circuit 220 is denoted as 2, the second output end of the boost control circuit 220 is denoted as 3, the first input end of the voltage control circuit 230 is denoted as 1, the second input end of the voltage control circuit 230 is denoted as 2, the control end of the voltage control circuit 230 is denoted as 3, the output end of the voltage control circuit 230 is denoted as 4, the port for outputting the first drive voltage VDD_MID1 in the output end of the voltage control circuit 230 is denoted as 4-1, and the port for outputting the second drive voltage VDD_MID2 in the output end of the voltage control circuit 230 is denoted as 4-2.

[0100] The input voltage output circuit 110 can obtain the second voltage Vo_Pre1 from the first power transistor group 310 and the third voltage Vo_Pre2 from the second power transistor group 320. Moreover, the input voltage output circuit 11 can use the maximum voltage among the second voltage Vo_Pre1 and the third voltage Vo_Pre2 as the input voltage Vin. That is to say, the input voltage output circuit 11 can use the maximum voltage among the first output voltage Vo1 and the second output voltage Vo2 as the input voltage Vin, and transmit the input voltage Vin to the boost conversion circuit 120 so that the boost conversion circuit 120 can obtain the input voltage Vin.

[0101] In this way, the boost conversion circuit 120 can boost the input voltage Vin to obtain the supply voltage VBST. Thus, the boost converter 100 can obtain the supply voltage VBST.

[0102] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the input voltage output circuit 110. As Figure 2 and Figure 3 shown, the input voltage output circuit 110 may include: a first diode D1 and a first capacitor C1.

[0103] The positive electrode of the first diode D1 is electrically connected to the first end of the power transistor group 300, the negative electrode of the first diode D1 is electrically connected to the upper plate of the first capacitor C1, the lower plate of the first capacitor C1 is electrically connected to the ground terminal of the isolated power supply 1000, and the input terminal of the boost conversion circuit 120 is electrically connected between the negative electrode of the first diode D1 and the upper plate of the first capacitor C1.

[0104] Wherein, the positive electrode of the first diode D1 is the input terminal of the input voltage output circuit 110, and the output terminal of the boost conversion circuit 120 is located between the negative electrode of the first diode D1 and the upper plate of the first capacitor C1.

[0105] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the boost conversion circuit 120. As Figure 2 and Figure 3 shown, the boost conversion circuit 120 may include: an inductor L1, a second capacitor C2, an upper transistor S2, and a lower transistor S1.

[0106] The first end of the inductor L1 is electrically connected to the output end of the input voltage output circuit 110, the second end of the inductor L1 is electrically connected to the first end of the upper transistor S2, the second end of the upper transistor S2 is electrically connected to the upper plate of the second capacitor C2, the first end of the lower transistor S1 is electrically connected between the second end of the inductor L1 and the first end of the upper transistor S2, the second input end of the secondary control circuit 200 is electrically connected between the second end of the upper transistor S2 and the upper plate of the second capacitor C2, and the second end of the lower transistor S1 and the lower plate of the second capacitor C2 are both electrically connected to the ground end of the isolated power supply 1000.

[0107] Among them, the first end of the inductor L1 is the input end of the boost conversion circuit 120, and the output end of the boost conversion circuit 120 is located between the second end of the upper transistor S2 and the upper plate of the second capacitor C2.

[0108] Among them, the lower transistor S1 can be integrated inside or outside the secondary control circuit 200. When the lower transistor S1 is integrated inside the secondary control circuit 200, since the secondary control circuit 200 is usually integrated into a chip. Therefore, the pins of the chip can be reduced, and the cost of the boost conversion circuit 120 can be reduced.

[0109] In addition, Figure 2 and Figure 3 only show the circuit structure in which the lower transistor S1 is integrated inside the secondary control circuit 200.

[0110] Among them, the lower transistor S1 can include but is not limited to gallium nitride transistors, insulated gate bipolar transistors, and metal-oxide semiconductor field effect transistors.

[0111] For example, when the lower transistor S1 is a gallium nitride transistor, the control end of the lower transistor S1 refers to the gate of the gallium nitride transistor, the first end of the lower transistor S1 is the drain of the gallium nitride transistor, and correspondingly, the second end of the lower transistor S1 is the source of the gallium nitride transistor.

[0112] For example, when the lower transistor S1 is a metal-oxide semiconductor field effect transistor, the control end of the lower transistor S1 refers to the gate of the metal-oxide semiconductor field effect transistor, the first end of the lower transistor S1 is the drain of the metal-oxide semiconductor field effect transistor, and correspondingly, the second end of the lower transistor S1 is the source of the metal-oxide semiconductor field effect transistor.

[0113] For example, when the lower transistor S1 is a field-controlled thyristor, the control end of the lower transistor S1 refers to the gate of the field-controlled thyristor, the first end of the lower transistor S1 is the drain of the field-controlled thyristor, and correspondingly, the second end of the lower transistor S1 is the source of the field-controlled thyristor.

[0114] In some examples, the lower transistor S1 is a field effect transistor, and the upper transistor S2 is a freewheeling diode D2.

[0115] The control terminal of the lower transistor S1 is electrically connected to the secondary control circuit 200.

[0116] The secondary control circuit 20 can control the turning on or off of the lower transistor S1.

[0117] Wherein, the positive electrode of the freewheeling diode D2 is the first end of the upper transistor S2, and the negative electrode of the freewheeling diode D2 is the second end of the upper transistor S2.

[0118] Wherein, when the upper transistor S2 is the freewheeling diode D2, the secondary control circuit 20 may not need to control the turning on or off of the upper transistor S2. Thus, the cost of the boost conversion circuit 120 can be reduced.

[0119] In addition, Figure 2 and Figure 3 only show the circuit structure where the upper transistor S2 is the freewheeling diode D2.

[0120] Based on the description of the above embodiments, exemplarily, a possible implementation manner of the secondary control circuit 200. As Figure 3 shown, the secondary control circuit 200 may include: a power management circuit 210, a boost control circuit 220, and a voltage control circuit 230.

[0121] The output terminal of the boost converter 100 is respectively electrically connected to the power supply terminal of the power management circuit 210, the input terminal of the boost control circuit 220, and the first input terminal of the voltage control circuit 230. The second input terminal of the voltage control circuit 230 is electrically connected to the first end of the power transistor group 300. The first output terminal of the boost control circuit 220 is electrically connected to the control terminal of the power management circuit 210. The second output terminal of the boost control circuit 220 is electrically connected to the control terminal of the voltage control circuit 230. The output terminal of the voltage control circuit 230 is electrically connected to the control terminal of the power transistor group 300.

[0122] Wherein, the second input terminal of the voltage control circuit 230 is the first input terminal of the secondary control circuit 200, and the power supply terminal of the power management circuit 210, the input terminal of the boost control circuit 220, and the first input terminal of the voltage control circuit 230 are all the second input terminals of the secondary control circuit 200.

[0123] When the supply voltage VBST is greater than the preset voltage, that is, when the supply voltage VBST has been established, the boost control circuit 220 can transmit an indication signal to the voltage control circuit 230, so that the voltage control circuit 230 can obtain the indication signal.

[0124] Wherein, the indication signal is used to instruct the voltage control circuit 230 to generate the driving voltage VDD_MID.

[0125] Thus, under the action of the indication signal, the voltage control circuit 230 can generate a driving voltage VDD_MID according to the supply voltage VBST and the first voltage Vo_Pre.

[0126] Among them, when the first voltage Vo_Pre is the second voltage Vo_Pre1, the voltage control circuit 230 can generate a first driving voltage VDD_MID1 according to the supply voltage VBST and the second voltage Vo_Pre1. When the first voltage Vo_Pre is the third voltage Vo_Pre2, the voltage control circuit 230 can generate a second driving voltage VDD_MID2 according to the supply voltage VBST and the third voltage Vo_Pre2.

[0127] When the supply voltage VBST is greater than the preset voltage, that is, when the supply voltage VBST has been established, the boost control circuit 220 can transmit a control signal to the power management circuit 210, so that the power management circuit 210 can obtain the control signal.

[0128] Among them, the control signal is used to control whether the supply voltage VBST supplies power to the power management circuit 210.

[0129] Thus, under the action of the control signal, the power management circuit 210 can use the supply voltage VBST as the power supply voltage of the secondary control circuit 200, so that the secondary control circuit 200 can work normally, and the secondary control circuit 200 is prevented from taking power from the voltage SRD. Thereby, the power supply efficiency of the secondary control circuit 200 is improved, and the problems of complex power-taking circuit, large area and power loss of the secondary control circuit 200 can be avoided.

[0130] In some examples, the output capacitor 500 may include: a first output capacitor Cout1 and a second output capacitor Cout2.

[0131] The first ends of the first power transistor group 310 and the second power transistor group 320 are both electrically connected to the opposite-named ends of the secondary winding of the transformer 400. The control ends of the first power transistor group 310 and the second power transistor group 320 are both electrically connected to the output end of the secondary control circuit 200. The second end of the first power transistor group 310 is electrically connected to the upper plate of the first output capacitor Cout1. The second end of the second power transistor group 320 is electrically connected to the upper plate of the second output capacitor Cout2. The lower plates of the first output capacitor Cout1 and the second output capacitor Cout2 are both electrically connected to the ground end of the isolated power supply 1000.

[0132] Finally, it should be noted that the above embodiments are only specific implementation manners of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A power supply circuit, characterized in that: The power supply circuit is applied to an isolated power supply, and the isolated power supply comprises: a secondary control circuit and at least two output branches; the power supply circuit comprises: a boost converter; The input end of the boost converter is electrically connected to the first end of the power tube group in the at least two output branches and the first input end of the secondary control circuit respectively, the output end of the boost converter is electrically connected to the second input end of the secondary control circuit, the output end of the secondary control circuit is electrically connected to the control end of the power tube group, and the second end of the power tube group is used to output the output voltage of the isolated power supply; The boost converter is used to obtain the first voltage from the power tube group, and perform boost processing on the first voltage to obtain a supply voltage, and transmit the supply voltage to the secondary control circuit, wherein the first voltage is used to characterize the magnitude of the output voltage; The secondary control circuit is used to obtain the first voltage from the power tube group, and generate a driving voltage according to the supply voltage and the first voltage, wherein the driving voltage is used to drive the power tube group to turn on or off.

2. The power supply circuit according to claim 1, characterized in that: The at least two output branches include: a first output branch and a second output branch, the first output branch includes a first power tube group, the second output branch includes a second power tube group, the first voltage includes: a second voltage and a third voltage, the output voltage includes: a first output voltage and a second output voltage, the driving voltage includes: a first driving voltage and a second driving voltage, the second voltage is used to characterize the magnitude of the first output voltage, and the third voltage is used to characterize the magnitude of the second output voltage; The first end of the first power tube group and the first end of the second power tube group are both electrically connected to the input end of the boost converter, the control end of the first power tube group and the control end of the second power tube group are both electrically connected to the output end of the secondary control circuit, the second end of the first power tube group is used to output the first output voltage, and the second end of the second power tube group is used to output the second output voltage; The boost converter is specifically used to obtain the second voltage from the first power tube group, and obtain the third voltage from the second power tube group, and use the maximum voltage of the second voltage and the third voltage as the input voltage of the boost converter; The boost converter is further specifically used to boost the input voltage to obtain the supply voltage, and transmit the supply voltage to the secondary control circuit; The secondary control circuit is specifically used to obtain the second voltage from the first power tube group, and to obtain the third voltage from the second power tube group, and to generate the first driving voltage according to the supply voltage and the second voltage, and to generate the second driving voltage according to the supply voltage and the third voltage.

3. The power supply circuit according to claim 2, characterized in that: The first power tube group includes: a first power tube and a second power tube, and the second power tube group includes: a third power tube and a fourth power tube; The source of the first power tube and the source of the third power tube are both electrically connected to the input end of the boost converter, the drain of the first power tube is electrically connected to the drain of the second power tube, the source of the second power tube is used to output the first output voltage, the drain of the third power tube is electrically connected to the drain of the fourth power tube, the source of the fourth power tube is used to output the second output voltage, and the gate of the first power tube, the gate of the second power tube, the gate of the third power tube and the gate of the fourth power tube are all electrically connected to the output end of the secondary control circuit.

4. The power supply circuit according to claim 2, characterized in that: The boost converter comprises: an input voltage output circuit and a boost conversion circuit; The input end of the input voltage output circuit is electrically connected to the first end of the power tube group, the output end of the input voltage output circuit is electrically connected to the input end of the boost conversion circuit, and the output end of the boost conversion circuit is electrically connected to the second input end of the secondary control circuit; The input voltage output circuit is used to obtain the second voltage from the first power tube group, and obtain the third voltage from the second power tube group, and use the maximum voltage of the second voltage and the third voltage as the input voltage, and transmit the input voltage to the boost conversion circuit; The boost conversion circuit is used to boost the input voltage to obtain the supply voltage.

5. The power supply circuit according to claim 4, characterized in that: The input voltage output circuit comprises: a first diode and a first capacitor; The positive electrode of the first diode is electrically connected to the first end of the power tube group, the negative electrode of the first diode is electrically connected to the upper plate of the first capacitor, the lower plate of the first capacitor is electrically connected to the ground end of the isolated power supply, and the input end of the boost conversion circuit is electrically connected between the negative electrode of the first diode and the upper plate of the first capacitor.

6. The power supply circuit according to claim 4, characterized in that: The boost conversion circuit comprises: an inductor, a second capacitor, an upper tube and a lower tube; The first end of the inductor is electrically connected to the output end of the input voltage output circuit, the second end of the inductor is electrically connected to the first end of the upper tube, the second end of the upper tube is electrically connected to the upper plate of the second capacitor, the first end of the lower tube is electrically connected between the second end of the inductor and the first end of the upper tube, the second input end of the secondary control circuit is electrically connected between the second end of the upper tube and the upper plate of the second capacitor, and the second end of the lower tube and the lower plate of the second capacitor are both electrically connected to the ground end of the isolated power supply.

7. The power supply circuit according to claim 6, characterized in that: The lower tube is a field effect transistor, and the upper tube is a freewheeling diode; The control end of the lower tube is electrically connected to the secondary control circuit; The secondary control circuit is also used to control the opening or closing of the lower tube.

8. The power supply circuit according to any one of claims 1 to 7, characterized in that: The secondary control circuit includes: a power management circuit, a boost control circuit and a voltage control circuit; The output end of the boost converter is electrically connected to the power supply end of the power management circuit, the input end of the boost control circuit and the first input end of the voltage control circuit respectively; the second input end of the voltage control circuit is electrically connected to the first end of the power tube group; the first output end of the boost control circuit is electrically connected to the control end of the power management circuit; the second output end of the boost control circuit is electrically connected to the control end of the voltage control circuit; and the output end of the voltage control circuit is electrically connected to the control end of the power tube group; The boost control circuit is used to transmit an indication signal to the voltage control circuit when the supply voltage is greater than a preset voltage, wherein the indication signal is used to instruct the voltage control circuit to generate the driving voltage; The voltage control circuit is used to generate the driving voltage according to the supply voltage and the first voltage under the action of the indication signal; The boost control circuit is further used to transmit a control signal to the power management circuit when the power supply voltage is greater than a preset voltage, and the control signal is used to control whether the power supply voltage supplies power to the power management circuit; The power management circuit is used to use the supply voltage as the power supply voltage of the secondary control circuit under the action of the control signal.

9. An isolated power supply, characterized in that: The isolated power supply comprises: a transformer, a secondary switch tube, at least two output branches, an output capacitor, a secondary control circuit and a power supply circuit as claimed in any one of claims 1 to 8; The opposite ends of the secondary winding of the transformer are respectively electrically connected to the first end of the power tube group in the at least two output branches, the first input end of the secondary control circuit and the input end of the power supply circuit, the control end of the power tube group is electrically connected to the output end of the secondary control circuit, the second end of the power tube group is electrically connected to the upper plate of the output capacitor, the same ends of the secondary winding of the transformer are respectively electrically connected to the drain of the secondary switch tube and the first end of the secondary control circuit, the gate of the secondary switch tube is electrically connected to the second end of the secondary control circuit, the source of the secondary switch tube, the ground end of the power supply circuit and the lower plate of the output capacitor are all electrically connected to the ground end of the isolated power supply, and the output end of the power supply circuit is electrically connected to the second input end of the secondary control circuit.

10. A chip, characterized in that: include: The power supply circuit according to any one of claims 1 to 8, and / or the isolated power supply according to claim 9.

11. An electronic device, characterized in that: include: The chip as claimed in claim 10.

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