Power supply

Abstract

A power supply is used for providing dual power output and comprises a first conversion circuit, a second conversion circuit, a control circuit, a first switching circuit, a second switching circuit and a change-over switch. When the control circuit receives a voltage demand of one of the first output end and the second output end of the power supply, the control circuit controls the first switching circuit to conduct a path from the first conversion circuit to one of the first output end and the second output end, and to turn off a path from the first conversion circuit to the other of the first output end and the second output end. Moreover, the control circuit controls the change-over switch and the second switching circuit to bidirectionally turn off paths from the second switching circuit to the first output end and the second output end, so as to prevent the first voltage from flowing back to the second switching circuit or prevent the second voltage from being mistakenly provided to the first output end and the second output end.

Description

Technical Field

[0001] The present invention relates to a power supply, and more particularly to a power supply with multiple voltage level outputs. Background Art

[0002] In recent years, consumer electronic devices have become increasingly popular. With the proliferation of various rechargeable consumer electronic devices such as mobile phones, notebook computers, tablet computers, and personal digital assistants (PDAs), most of these electronic devices need to use a charging device to charge them. Therefore, the demand for charging devices has gradually increased. With the improvement of the power supply capacity of charging devices, charging devices with multiple USB chargers that can charge multiple products simultaneously have emerged.

[0003] However, in the current applications of multiple USB charger outputs on the market, most use a converter plus multiple step-down converters at the rear stage for step-down operations. Therefore, the output of the converter must be further stepped down by these step-down converters respectively before it can charge the electronic device. Although this architecture is simple to control, the number of components of multiple step-down converters is large, and it occupies a large volume. In addition, it will also reduce the efficiency due to the line loss during the period. Moreover, it is necessary to consider that the voltages of each charger are different, which may cause the charger with a higher voltage to be reversely back-fed through the internal circuit of the charging device to the step-down converter with a lower voltage, resulting in the risk of charging device failure.

[0004] Therefore, how to design a power supply to prevent the occurrence of the above voltage back-feeding situation has become a major research topic for the inventor. Summary of the Invention

[0005] To solve the above problems, the present invention provides a power supply to overcome the problems of the prior art. Therefore, the power supply of the present invention is used to provide dual power outputs, and the power supply includes a first conversion circuit, a second conversion circuit, a control circuit, a first switching circuit, a second switching circuit, and a switching switch. The first conversion circuit converts the input voltage into a first voltage. The second conversion circuit is coupled to the first conversion circuit and converts the first voltage into a second voltage. The control circuit is coupled to the first conversion circuit and the second conversion circuit, and the first switching circuit is coupled to the control circuit, the first conversion circuit, a first output terminal, and a second output terminal. The second switching circuit is coupled to the control circuit, the first output terminal, and the second output terminal, and the switching switch is coupled to the control circuit, the second conversion circuit, and the second switching circuit. When the control circuit receives a voltage demand at one of the first output terminal and the second output terminal, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to one of the terminals and turn off the path of the first conversion circuit to the other terminal, and controls the switching switch and the second switching circuit to bidirectionally turn off the path of the second conversion circuit to the first output terminal and the second output terminal to prevent the first voltage from being back-fed to the second conversion circuit or the second voltage from being erroneously provided to the first output terminal and the second output terminal.

[0006] To solve the above problems, the present invention provides a power supply to overcome the problems of the prior art. Therefore, the power supply of the present invention is used to provide multiple power outputs, and the power supply includes a first conversion circuit, a plurality of second conversion circuits, a control circuit, a first switching circuit, a plurality of second switching circuits, and a plurality of switching switches. The first conversion circuit converts the input voltage into a first voltage. The plurality of second conversion circuits are coupled to the first conversion circuit and convert the first voltage into a plurality of second voltages. The control circuit is coupled to the first conversion circuit and the second conversion circuits, and the first switching circuit is coupled to the control circuit, the first conversion circuit, and a plurality of output terminals. The plurality of second switching circuits are coupled to the control circuit and the output terminals, and the plurality of switching switches are coupled to the control circuit and are correspondingly coupled to the second conversion circuits and the second switching circuits. When the control circuit receives the same voltage demand at one of the output terminals, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the output terminal and turn off the path of the first conversion circuit to the remaining terminals, and controls the switching switches and the second switching circuits to correspondingly and bidirectionally turn off the paths of the second conversion circuits to the output terminals to prevent the first voltage from being back-fed to the second conversion circuits or the second voltages from being erroneously provided to the output terminals.

[0007] The main purpose and effect of the present invention is that through the configuration of the second switching circuit and the switching switch, the present invention can bidirectionally turn off the paths of the second conversion circuit to the first output terminal and the second output terminal to prevent the first voltage from being back-fed to the second conversion circuit or the second voltage from being erroneously provided to the first output and the second output.

[0008] To further understand the technologies, means and effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be deeply and specifically understood therefrom. However, the attached drawings are only for reference and illustration, and are not used to limit the present invention. Description of the Drawings

[0009] Figure 1 It is a circuit block diagram of the first embodiment of the power supply of the present invention.

[0010] Figure 2 It is a detailed circuit block diagram of the first embodiment of the power supply of the present invention.

[0011] Figure 3A It is a circuit block diagram of the first embodiment of the second switching circuit of the present invention.

[0012] Figure 3B It is a circuit block diagram of the second embodiment of the second switching circuit of the present invention.

[0013] Figures 4A to 4E They are respectively schematic diagrams of the first to fifth embodiments of the output voltage supply path of the power supply of the present invention.

[0014] Figure 5A It is a circuit block diagram of the second embodiment of the power supply of the present invention.

[0015] Figure 5B It is a circuit block diagram of the third embodiment of the power supply of the present invention.

[0016] Among them, the reference numerals are:

[0017] BR: Rectifier circuit 100: Power supply

[0018] 1: First conversion circuit 2, 2_1~2-n: Second conversion circuit

[0019] 3: Control circuit 4: First switching circuit

[0020] 5, 5_1~5-n: Second switching circuit 6: Switch

[0021] Q1~Q2: Switches D1, D2, D6: Junction diodes

[0022] A: First output terminal B: Second output terminal

[0023] A_1~A_n: Output terminals Vin: Input voltage

[0024] Vo1: First voltage Vo2, Vo2_1~Vo2_n: Second voltages

[0025] L1 to L4: Paths Detailed implementation manners

[0026] Regarding the technical content and detailed description of the present invention, it is described in conjunction with the drawings as follows:

[0027] Please refer to Figure 1 It is a circuit block diagram of the first embodiment of the power supply of the present invention. The power supply 100 receives an input voltage Vin, and the power supply 100 includes a rectification circuit BR, a first conversion circuit 1, a second conversion circuit 2, a control circuit 3, a first switching circuit 4, a second switching circuit 5, and a switching switch 6. The input end of the first conversion circuit 1 is coupled to the rectification circuit BR, and the output end of the first conversion circuit 1 is coupled to one end of the first switching circuit 4. The input end of the second conversion circuit 2 is coupled to the output end of the first conversion circuit 1, and the output end of the second conversion circuit 2 is coupled to one end of the switching switch 6. The power supply 100 includes a first output terminal A and a second output terminal B, and the other end of the first switching circuit 4 is coupled to the first output terminal A and the second output terminal B. One end of the second switching circuit 5 is coupled to the other end of the switching switch 6, and the other end of the second switching circuit 5 is coupled to the first output terminal A and the second output terminal B. The control circuit 3 can be coupled to the second conversion circuit 2, the first switching circuit 4, the second switching circuit 5, and the switching switch 6 to perform corresponding operations on the second conversion circuit 2, the first switching circuit 4, the second switching circuit 5, and the switching switch 6 accordingly.

[0028] Among them, the first output terminal A and the second output terminal B can be used to plug in a load 200 respectively, so that the power supply 100 can communicate with the load 200 through the first output terminal A or the second output terminal B, or the power supply 100 can supply power to the load 200 through the first output terminal A or the second output terminal B. It is worth mentioning that in one embodiment, the first conversion circuit 1 can preferably be a flyback converter to provide electrical isolation between the input end and the output end of the power supply 100, but not limited thereto. Any switching converter that can convert the input voltage Vin and supply power to the load 200 should be included in the scope of this embodiment. In addition, in one embodiment, the first output terminal A and the second output terminal B can preferably be Type-C connection terminals, but not limited thereto. Any connection terminal that can transmit communication signals and provide different levels of voltage to the load 200 should be included in the scope of this embodiment.

[0029] Furthermore, the rectifier circuit BR rectifies the input voltage Vin into a DC voltage Vdc, and a controller (not shown in the figure, which can be integrated into the control circuit 3 or independently configured inside the first conversion circuit 1) inside the first conversion circuit 1 controls the first conversion circuit 1 to convert the input voltage Vin into a first voltage Vo1. Among them, if the controller inside the first conversion circuit 1 is independently configured inside the first conversion circuit 1, the control circuit 3 can provide a control signal to the controller inside the first conversion circuit 1 to control the power conversion of the first conversion circuit 1. The control circuit 3 controls the second conversion circuit 2 to convert the first voltage Vo1 into a second voltage Vo2. Since the first conversion circuit 1 is generally a converter with an isolation transformer to electrically isolate its input and output ends, the second conversion circuit 2 is preferably a non-isolated converter. Among them, the second conversion circuit 2 is preferably a buck converter to convert the relatively high-level first voltage Vo1 into a relatively low-level second voltage Vo2, but it is not limited thereto. Therefore, the second conversion circuit 2 can also be, for example but not limited to, a boost converter or a buck-boost converter, depending on the operation and application of the power supply 100.

[0030] On the other hand, the control circuit 3 also controls the conduction / turn-off of the first switching circuit 4, the second switching circuit 5, and the switching switch 6 to control the power supply 100 to provide the first voltage Vo1 or the second voltage Vo2 to the first output terminal A or the second output terminal B. Specifically, the control circuit 3 can include a Power Delivery (PD) controller, which generally has a USB-PD protocol. Therefore, the control circuit 3 can obtain the output voltage level required by the load 200 through handshaking communication with the load 200. Generally speaking, when one or more loads 200 are plugged into the first output terminal A or the second output terminal B, the control circuit 3 can know that there is a device plugged in through the detection pins of the output terminals A and B. Then, the power supply 100 must provide a default voltage (such as but not limited to 5V) to the output terminals A and B coupled to the load 200 (which can be provided by the first conversion circuit 1 or the second conversion circuit 2, and there will be more detailed explanations later), and based on this, it can further handshake and communicate with the load 200 through the detection pins of the output terminals A and B.

[0031] Therefore, the control circuit 3 needs to control the first switching circuit 4, the second switching circuit 5, and the switching switch 6 to conduct corresponding paths (which will be further described later), so that the first conversion circuit 1 or the second conversion circuit 2 can provide a default voltage to the output terminals A and B coupled to the load 200. Then, after the control circuit 3 knows the voltage level required by the load 200 through communication, it controls the first conversion circuit 1 or the second conversion circuit 2 to provide the first voltage Vo1 or the second voltage Vo2 that meets the requirements of the load 200 to the load 200. Among them, the power supply 100 uses the first voltage Vo1 provided by the first conversion circuit 1 as the main power supplier, and the second voltage Vo2 provided by the second conversion circuit 2 as the secondary power supplier.

[0032] When the first load 200 is plugged into the output terminals A and B, the control circuit 3 knows the voltage level required by this load 200 through the default voltage and handshake communication. And regardless of the voltage level it requires, the power supply 100 uses the first conversion circuit 1 to convert the input voltage Vin into the first voltage Vo1 (the same as the voltage level required by the load 200). At the same time, the control circuit 3 controls the second conversion circuit 2, the first switching circuit 4, the second switching circuit 5, and the switching switch 6 accordingly to supply the first voltage Vo1 to the corresponding output terminals A and B. After that, when another load 200 is plugged in, the control circuit 3 knows the voltage level required by another load 200 through the default voltage and handshake communication. And after comparing the voltage level required by this load 200 with the first voltage Vo1, it controls the second conversion circuit 2, the first switching circuit 4, the second switching circuit 5, and the switching switch 6 accordingly to supply the output voltages (i.e., the first voltage Vo1 and the second voltage Vo2) of the voltage levels required by the two loads 200 respectively.

[0033] It is worth mentioning that in an embodiment, since the control circuit 3 can perform handshake communication if it includes a power delivery controller, it does not exclude that the control circuit 3 can know the parameters of the load 200 through other communication methods (such as, but not limited to, detecting the parameters of the load 200 and comparing them with the data in the internal storage device for confirmation). Therefore, the control circuit 3 is not limited to only using the operation method of handshake communication. However, for the convenience of detailed description of the technical features of the present invention, a schematic example of handshake communication will be given later.

[0034] Furthermore, when the power supply 100 supplies the first voltage Vo1 to the load 200 coupled to the first output terminal A or the second output terminal B, the first voltage Vo1 may flow back reversely to the output terminal of the second conversion circuit 2, causing the second conversion circuit 2 to consume extra power due to the backflow of the first voltage Vo1, or even malfunction due to the backflow, which may lead to the failure of the second conversion circuit 2. Similarly, when the second conversion circuit 2 supplies the second voltage Vo2 (such as but not limited to the default voltage 5V), but the current situation does not allow the second voltage Vo2 to be supplied to the first output terminal A and the second output terminal B, it is also necessary to prevent the second voltage Vo2 from being conducted to the first output terminal A and the second output terminal B. Therefore, the main object and effect of the present invention is that through the configuration of the second switching circuit 5 and the switching switch 6, the present invention can bidirectionally cut off the path from the second conversion circuit 2 to the first output terminal A and the second output terminal B, so as to prevent the first voltage Vo1 from flowing back to the second conversion circuit 2, or prevent the second voltage Vo2 from being mistakenly supplied to the first output terminal A and the second output terminal B.

[0035] Specifically, when the first load 200 is coupled to one of the first output terminal A and the second output terminal B, the control circuit 3 knows that there is a device coupled through the detection pins of the output terminals A and B. Then, the control circuit 3 performs corresponding control on the first switching circuit 4, the second switching circuit 5 and the switching switch 6 to supply the default voltage (5V) converted by the first conversion circuit 1 to the corresponding end (assumed to be the first output terminal A). That is, the control circuit 3 controls the first switching circuit 4 to conduct the path from the first conversion circuit 1 to one end (i.e., the first output terminal A), and cut off the path from the first conversion circuit 1 to the other end (i.e., the second output terminal B), and controls the switching switch 6 and the second switching circuit 5 to bidirectionally cut off the path from the second conversion circuit 2 to the first output terminal A and the second output terminal B. In this way, it is possible to prevent the default voltage (5V) from flowing back to the second conversion circuit 2, or prevent the second voltage Vo2 (assuming the operating condition of the second conversion circuit 2, the second voltage Vo2 is the default voltage of 5V) from being mistakenly supplied to the first output terminal A and the second output terminal B.

[0036] Then, the control circuit 3 communicates with the load 200 through the detection pins at one corresponding end (i.e., the first output terminal A) to obtain the voltage requirement of the load 200 (i.e., the voltage level required by the load 200). Moreover, the control circuit 3 controls the first conversion circuit 1 to convert the input voltage Vin into the first voltage Vo1 corresponding to the voltage requirement. Then, the control circuit 3 continuously controls the first switching circuit 4 to conduct the path from the first conversion circuit 1 to the first output terminal A and turn off the path from the first conversion circuit 1 to the second output terminal B, so as to supply the first voltage Vo1 to the load 200 coupled to the first output terminal A. Moreover, the control circuit 3 also controls the switching switch 6 and the second switching circuit 5 to bidirectionally turn off the paths from the second conversion circuit 2 to the first output terminal A and the second output terminal B, so as to prevent the first voltage Vo1 from being back-fed to the second conversion circuit 2, or prevent the second voltage Vo2 from being erroneously supplied to the first output terminal A and the second output terminal B.

[0037] Please refer to Figure 2 the detailed circuit block diagram of the first embodiment of the power supply of the present invention, and also refer to Figure 1 . A preferred implementation of the first switching circuit 4 is that the first switching circuit 4 includes a plurality of first switches Q1, and a preferred implementation of the second switching circuit 5 is that the second switching circuit 5 includes a plurality of second switches Q2. Among them, the number of the first switches Q1 corresponds to the number of the output terminals A and B, and the number of the second switches Q2 also corresponds to the number of the output terminals A and B. Therefore, in Figure 1 the power supply 100 in the embodiment includes two groups of the first switches Q1 and the second switches Q2 respectively. One end of each first switch Q1 is coupled to the first conversion circuit 1, and the other end of each first switch Q1 is respectively coupled to the first output terminal A and the second output terminal B, and the control end of each first switch Q1 is coupled to the control circuit 3. Similarly, one end of each second switch Q2 is coupled to the switching switch 6, and the other end of each second switch Q2 is respectively coupled to the first output terminal A and the second output terminal B, and the control end of each second switch Q2 is coupled to the control circuit 3.

[0038] Since the switching switch 6 and the second switching circuit 5 must provide the function of bidirectionally shutting off the path between the second conversion circuit 2 and the output terminals A and B, the switching switch 6 and the second switch Q2 must form a reverse-connected structure. Specifically, the first switch Q1, the second switch Q2, and the switching switch 6 are preferably metal-oxide-semiconductor field-effect transistors (MOSFETs). The main reason is that when a MOSFET is turned on, its on-resistance is relatively low. Therefore, the power loss when the first switch Q1, the second switch Q2, and the switching switch 6 are turned on can be significantly reduced. However, when a MOSFET is not turned on, due to the presence of junction diodes D1, D2, D6 (body diodes), even when it is turned off, there will still be a unidirectional conduction path. Therefore, the reverse-connected structure of the switching switch 6 and the second switch Q2 means that the forward-bias directions of the junction diodes D2 and D6 of the two are opposite, so that when both the switching switch 6 and the second switch Q2 are turned off, a bidirectional shut-off structure can be formed.

[0039] Furthermore, the configuration of the junction diode D1 of the first switch Q1 can be reverse-biased from the first conversion circuit 1 to the first output terminal A and the second output terminal B. In this way, it is possible to prevent the first voltage Vo1 provided by the first conversion circuit 1 from being wrongly provided to the first output terminal A and the second output terminal B (in accordance with the USB-PD protocol specification, when the load 200 is removed, there should be no voltage on the output terminals A and B). On the other hand, the configuration of the junction diode D2 of the second switch Q2 is forward-biased from the switching switch 6 to the first output terminal A and the second output terminal B to prevent the voltage on the output terminals A and B from being fed back to the second conversion circuit 2. The configuration of the junction diode D6 of the switching switch 6 is reverse-biased from the second conversion circuit 2 to the second switch Q2 to prevent the second voltage Vo2 from being fed back to the output terminals A and B (in accordance with the USB-PD protocol specification, when the load 200 is removed, there should be no voltage on the output terminals A and B). In this way, by reversing the connection of the junction diode D2 and the junction diode D6, the effect of bidirectionally shutting off the second conversion circuit 2 from the first output terminal A and the second output terminal B can be achieved when the second switch Q2 and the switching switch 6 are turned off.

[0040] Similarly, the configuration of the junction diode D2 of the second switch Q2 is reverse-biased from the switching switch 6 to the first output terminal A and the second output terminal B, and the configuration of the junction diode D6 of the switching switch 6 is forward-biased from the second conversion circuit 2 to the second switch Q2. Through such a configuration, the effect of bidirectionally shutting off the second conversion circuit 2 from the first output terminal A and the second output terminal B can also be achieved when the second switch Q2 and the switching switch 6 are turned off. It is worth mentioning that in one embodiment, in addition to Figure 2In addition to the embodiments described, there are numerous other embodiments that can achieve the same effect. Therefore, this embodiment only presents relatively simple and low-cost embodiments, but is not limited thereto. For example, the effect of bidirectional shutdown can also be achieved by connecting two metal-oxide-semiconductor field-effect transistors (MOSFETs) in reverse, or replacing the MOSFET with a thyristor also has the function of a shutdown path, etc., which will not be elaborated here one by one. In addition, Figure 2 the circuit structures, coupling relationships, and operating methods not described Figure 1 are the same as those described in

[0041] Please refer to Figure 3A which is the circuit block diagram of the first embodiment of the second switching circuit of the present invention, Figure 3B which is the circuit block diagram of the second embodiment of the second switching circuit of the present invention, and also refer to Figures 1 to 2 . In Figure 3A , the second switch Q2 can be a diode that does not require a control circuit 3 to control its conduction / shutdown, so that it can be forward-biased / reverse-biased naturally according to the level of the voltage. Alternatively, the second switch Q2 can also be a thyristor that still requires a control signal provided by the control circuit 3 to control its conduction / shutdown. In Figure 3B , the second switch Q2 can be a metal-oxide-semiconductor field-effect transistor (MOSFET), and the second switch Q2 can be an N-type MOSFET or a P-type MOSFET, which will not be elaborated here.

[0042] Please refer to Figures 4A to 4E which are the schematic diagrams of the first to fifth embodiments of the output voltage supply path of the power supply of the present invention, and also refer to Figures 1 to 3B . Among them, Figures 4A to 4E in Figures 1 to 2 the circuit architecture of the power supply 100 of Figure 4AIn this case, the power supply 100 detects that a load 200 is plugged into the first output terminal A, and after handshake communication, it knows the voltage requirement of the load 200. Therefore, the control circuit 3 controls the first conversion circuit 1 to convert the input voltage Vin into a first voltage Vo1 corresponding to the voltage requirement. Then, in the first switching circuit 4, the control circuit 3 controls the first switch Q1 coupled to the first output terminal A to turn on, so as to turn on the path from the first conversion circuit 1 to the first output terminal A. Moreover, in the first switching circuit 4, the control circuit 3 also controls the first switch Q1 coupled to the second output terminal B to turn off, so as to turn off the path from the first conversion circuit 1 to the second output terminal B. Therefore, the first voltage Vo1 can be provided to the load 200 coupled to the first output terminal A through the first path L1. On the other hand, the control circuit 3 also controls the change-over switch 6 and the two second switches Q2 of the second switching circuit 5 to turn off, so as to bidirectionally turn off the paths from the second conversion circuit 2 to the first output terminal A and the second output terminal B. Therefore, the backflow of the first voltage Vo1 to the second conversion circuit 2 or the mis-providing of the second voltage Vo2 to the first output terminal A and the second output terminal B can be prevented. In Figure 4B this case, its operation mode is the same as that in Figure 4A except that the load 200 is plugged into the second output terminal B, so the on / off states of the first switch Q1 are swapped. Therefore, the first voltage Vo1 can be provided to the load 200 coupled to the second output terminal B through the second path L2.

[0043] In Figure 4C this case, the power supply 100 detects that a load 200 is plugged into the first output terminal A and another load 200 is plugged into the second output terminal B, and after handshake communication, it knows that the voltage requirements of the two loads 200 are the same. Therefore, the control circuit 3 controls the first conversion circuit 1 to convert the input voltage Vin into a first voltage Vo1 corresponding to the voltage requirement. Then, in the first switching circuit 4, the control circuit 3 controls the first switch Q1 coupled to the first output terminal A and the first switch Q1 coupled to the second output terminal B to turn on, so as to turn on the paths from the first conversion circuit 1 to the first output terminal A and the second output terminal B. Therefore, the first voltage Vo1 can be provided to the load 200 coupled to the first output terminal A and the load 200 coupled to the second output terminal B through the first path L1 and the second path L2 respectively. On the other hand, the control circuit 3 also controls the change-over switch 6 and the two second switches Q2 of the second switching circuit 5 to turn off, so as to bidirectionally turn off the paths from the second conversion circuit 2 to the first output terminal A and the second output terminal B. Therefore, the backflow of the first voltage Vo1 to the second conversion circuit 2 or the mis-providing of the second voltage Vo2 to the first output terminal A and the second output terminal B can be prevented.

[0044] In Figure 4DIn the figure, the power supply 100 detects that a load 200 is plugged into the first output terminal A, and a load 200 is also plugged into the second output terminal B. After handshake communication, the control circuit 3 learns that the voltage requirements of the two loads 200 are different, and the voltage requirement of the first output terminal A is greater than that of the second output terminal B. Therefore, the control circuit 3 controls the first conversion circuit 1 to convert the input voltage Vin into a first voltage Vo1 corresponding to the voltage requirement of the first output terminal A, and controls the second conversion circuit 2 to convert the first voltage Vo1 into a second voltage Vo2 corresponding to the voltage requirement of the second output terminal B. Then, in the control circuit 3, the first switch Q1 coupled to the first output terminal A in the first switching circuit 4 is turned on to conduct the path from the first conversion circuit 1 to the first output terminal A (i.e., the one with higher voltage requirement). Moreover, in the control circuit 3, the second switch Q2 coupled to the second output terminal B in the second switching circuit 5 is turned on to conduct the path from the second conversion circuit 2 to the second output terminal B (i.e., the one with lower voltage requirement). Therefore, the first voltage Vo1 can be provided to the load 200 coupled to the first output terminal A through the first path L1, and the second voltage Vo2 can be provided to the load 200 coupled to the second output terminal B through the third path L3.

[0045] On the other hand, the control circuit 3 also controls the first switch Q1 coupled to the second output terminal B (i.e., the one with lower voltage requirement) in the first switching circuit 4 to turn off, so as to turn off its second path L2 and prevent the first voltage Vo1 from being erroneously provided to the second output terminal B. Moreover, the control circuit 3 also controls the switching switch 6 and the two second switches Q2 coupled to the first output terminal A (i.e., the one with higher voltage requirement) in the second switching circuit 5 to turn off, so as to bidirectionally turn off the path from the second conversion circuit 2 to the first output terminal A. Therefore, the first voltage Vo1 can be prevented from being back-fed to the second conversion circuit 2, or the second voltage Vo2 from being erroneously provided to the first output terminal A.

[0046] In Figure 4E the operation mode is similar to that of Figure 4D except that the voltage requirement of the first output terminal A is less than that of the second output terminal B, so the on-off relationship of the switches Q1 and Q2 in the first switching circuit 4 and the second switching circuit 5 is reversed. Therefore, the first voltage Vo1 can be provided to the load 200 coupled to the second output terminal B through the second path L2, and the second voltage Vo2 can be provided to the load 200 coupled to the first output terminal A through the fourth path L4.

[0047] In Figures 4C to 4E the embodiment, it is mainly the path diagram of the stable power supply state after the load 200 has been plugged in. However, when the load 200 is plugged into the first output terminal A and the second output terminal B (i.e., the tentative power supply state), the control circuit 3 will adjust its power supply paths L1 - L4 based on the result of handshake communication, and its main logic depends on Figure 1As described, "The power supply 100 is regulated with the first voltage Vo1 provided by the first conversion circuit 1 as the main power supplier and the second voltage Vo2 provided by the second conversion circuit 2 as the secondary power supplier." Further, in a conventional power supply, when any one output terminal is first inserted into a load 200 and then the other output terminal is inserted into another load 200, the voltages at both output terminals need to first return to the default voltage of 5V. Then, after handshake communication, they return to the voltages required at each output terminal. Therefore, if the power output at each output terminal is insufficient or there is no battery station for the load 200 to supplement the power source, the load 200 will be at risk of power outage. Therefore, to improve this problem, the present invention further uses a voltage supply power switching control method to control the first conversion circuit 1 and the second conversion circuit 2 to avoid power outage due to instantaneous allocation of the output voltage and make the user experience smoother.

[0048] Specifically, assume that only the first output terminal A is plugged into a load 200, and the stable power supply state after the first voltage Vo1 provided by the first conversion circuit 1 is supplied to the first output terminal A through the first switching circuit 4 is taken as an example. Under this condition, when another load 200 is plugged into the second output terminal B, the control circuit 3 performs the Figure 1 handshake communication described to obtain the voltage requirement of the second output terminal B. Specifically, when the control circuit 3 detects through the detection pin of the second output terminal B that a device is coupled, the control circuit 3 first turns on the switching switch 6 and the second switch Q2 of the second switching circuit 5 that is coupled to the second output terminal B, so that the second conversion circuit 2 can first provide the default voltage of 5V for handshake communication with the load 200 coupled to the second output terminal B, so that the control circuit 3 can obtain the voltage requirement of the second output terminal B through the handshake communication. Then, the control circuit 3 compares the voltage requirements of the first output terminal A and the second output terminal B to confirm what operation should be performed next and accordingly determine whether the power supplier for the second output terminal B is the first conversion circuit 1 or the second conversion circuit 2.

[0049] When the voltage requirement of the first output terminal A is higher than that of the second output terminal B, the control circuit 3 performs Figure 4D the circuit operation. Therefore, the control circuit 3 controls the first conversion circuit 1 to provide the first voltage Vo1, and controls the second conversion circuit 2 to convert the first voltage Vo1 into the second voltage Vo2 required to satisfy the load 200 coupled to the second output terminal B. And the control circuit 3 controls the power supply 100 to keep the first path L1 from the first conversion circuit 1 to the first output terminal A conducting, and the third path L3 from the second conversion circuit 2 to the second output terminal B conducting, to respectively provide the first voltage Vo1 and the second voltage Vo2 to the corresponding load 200. On the other hand, the control circuit 3 keeps the second path L2 off and keeps the fourth path L4 bidirectionally off to avoid incorrect provision of the output voltage.

[0050] When the voltage requirement of the first output terminal A is equal to the voltage requirement of the second output terminal B, the control circuit 3 performs Figure 4C circuit operations. Therefore, the control circuit 3 controls the first conversion circuit 1 to provide the first voltage Vo1, and controls the power supply 100 to turn on the first path L1 and the second path L2 from the first conversion circuit 1 to the first output terminal A and the second output terminal B to supply the first voltage Vo1 to the two loads 200. On the other hand, the control circuit 3 maintains the two-way cutoff of the third path L3 and the fourth path L4 to prevent the output voltage from being provided incorrectly.

[0051] When the voltage requirement of the first output terminal A is lower than the voltage requirement of the second output terminal B, since the power supply 100 is regulated based on "the first voltage Vo1 provided by the first conversion circuit 1 is the main power supplier, and the second voltage Vo2 provided by the second conversion circuit 2 is the secondary power supplier" to perform Figure 4E circuit operations. Therefore, the control circuit 3 controls the first conversion circuit 1 to provide the first voltage Vo1 that meets the requirements of the load 200 coupled to the second output terminal B, and controls the second conversion circuit 2 to convert the first voltage Vo1 into the second voltage Vo2 that meets the requirements of the load 200 coupled to the first output terminal A. Moreover, the control circuit 3 controls the power supply 100 to turn off the first path L1 from the first conversion circuit 1 to the first output terminal A, and maintains the two-way cutoff of the third path L3 from the second conversion circuit 2 to the second output terminal B to prevent the output voltage from being provided incorrectly. On the other hand, the control circuit 3 controls the power supply 100 to turn on the second path L2 from the first conversion circuit 1 to the second output terminal B, and turn on the fourth path L4 from the second conversion circuit 2 to the first output terminal A to supply the first voltage Vo1 and the second voltage Vo2 to the corresponding loads 200 respectively.

[0052] In addition, when only the second output terminal B is plugged with a load 200 and the first voltage Vo1 provided by the first conversion circuit 1 is in a stable power supply state after being provided to the second output terminal B through the first switching circuit 4, the operation logic is the same, and the operations of the switches Q1 and Q2 are contrary to the above examples and will not be elaborated here. Therefore, from the above Figures 4A to 4E operation methods, the operation timings of Tables 1 to 3 can be sorted out. Specifically, in Tables 1 to 3, the timing progresses from 0 to T3, and the closer to 0, the earlier the operation is performed. In addition, for the convenience of explaining which switch conducts / shuts off the operation, therefore, in Figures 4A to 4E the first switch Q1 and the second switch Q2 from the first output terminal A to the second output terminal B are represented in sequence as Q1-1, Q1-2, Q2-1, Q2-2 to avoid confusion about which one is actuated.

[0053] In Table 1 below, the voltage requirement of the load 200 plugged into the first output terminal A is 20V, and the voltage requirement of the load 200 plugged into the second output terminal B is also 20V. Moreover, after the first output terminal A plugs in the load 200 first (timing T1), the second output terminal B then plugs in the load 200 (timing T2). And after the second output terminal B plugs in the load 200, the load 200 plugged into the first output terminal A is removed (timing T3).

[0054] Table 1

[0055]

[0056] In Table 2 below, the voltage requirement of the load 200 plugged into the first output terminal A is 20V, and the voltage requirement of the load 200 plugged into the second output terminal B is 9V. Moreover, after the first output terminal A plugs in the load 200 first (timing T1), the second output terminal B then plugs in the load 200 (timing T2). And after the second output terminal B plugs in the load 200, the load 200 plugged into the first output terminal A is removed (timing T3).

[0057] Table 2

[0058]

[0059]

[0060] In Table 3 below, the voltage requirement of the load 200 plugged into the first output terminal A is 9V, and the voltage requirement of the load 200 plugged into the second output terminal B is 20V. Moreover, after the first output terminal A plugs in the load 200 first (timing T1), the second output terminal B then plugs in the load 200 (timing T2). And not long after the second output terminal B plugs in the load 200, the load 200 plugged into the second output terminal B is removed (timing T3).

[0061] Table 3

[0062]

[0063] As can be seen from the above Tables 1 to 3, when the load 200 is plugged into the output terminals A and B, the power supply 100 will handshake and communicate with the load at the default voltage (5V), and after confirming the required voltage of the load, it will decide to provide the first voltage Vo1 or the second voltage Vo2 to supply power to it, and supply power to the plugged load 200 by operating the corresponding switches Q1-1, Q1-2, Q2-1, Q2-2, and the switching switch 6 to provide a suitable power path. On the other hand, although in the present invention, the load 200 is first plugged into the first output terminal A and then into the second output terminal B as an example, if it is changed to the load 200 being first plugged into the second output terminal B and then into the first output terminal A, the operation timing is the same as that in the above Tables 1 to 3, except that the providers of the voltages Vo1 and Vo2 are exactly opposite, and the operations of the switches Q1-1, Q1-2, Q2-1, Q2-2, and 6 are also exactly opposite, which will not be elaborated here.

[0064] Please refer to Figure 5A which is a circuit block diagram of the second embodiment of the power supply of the present invention, and also refer to Figures 1 to 4E . Figure 5A The difference between the power supply 100 of this embodiment and the Figure 1 power supply 100 in terms of circuit is that the power supply 100 includes a plurality of output terminals A_1 to A_n. Therefore, the power supply 100 correspondingly includes a plurality of second conversion circuits 2_1 to 2-n, a plurality of second switching circuits 5, 5_1 to 5-n, and a plurality of switching switches 6 based on the plurality of output terminals A_1 to A_n. The second conversion circuits 2_1 to 2-n respectively convert the first voltage Vo1 into second voltages Vo2_1 to Vo2_n, and the levels of the second voltages Vo2_1 to Vo2_n can be the same or different. Each of the second conversion circuits 2_1 to 2-n is respectively coupled to one of the output terminals A_1 to A_n through a second switching circuit 5_1 to 5-n and a switching switch 6. Therefore, the number of the second switching circuits 5_1 to 5-n and the switching switches 6 will correspond to the number of the second conversion circuits 2_1 to 2-n. Therefore, assuming that there are 5 output terminals A_1 to A_n, the number of the first switches Q1 inside the first switching circuit 4 is 5, and the number of the second switches Q2 inside each of the second switching circuits 5_1 to 5-n is also 5.

[0065] Basically, Figure 5A the operation mode of the power supply 100 is the same as that of the Figure 1 power supply, and its detailed operation mode and the paths L1 to L4 that can be formed are similar to those of the Figures 2 to 4E . Therefore, its main logic is similar to that of the Figure 1As described above, "the power supply 100 is regulated with the first voltage Vo1 provided by the first conversion circuit 1 as the main power supplier and the second voltages Vo2_1 to Vo2_n provided by the second conversion circuits 2_1 to 2_n as the secondary power suppliers". Therefore Figure 5A the operation mode, detailed actions, and possible paths of the power supply 100 can be inferred from Figures 1 to 4E the description therein and will not be elaborated here. Moreover, the achievable effects are also similar to Figures 1 to 4E the description therein, having the functions of bidirectional shutdown and avoiding power-off due to instantaneous regulation of the output voltage.

[0066] On the other hand, Figure 5A the difference in the operation mode between the power supply 100 of the embodiment and Figure 1 the power supply 100 of Figure 5A is that since the power supply 100 of Figure 5A includes multiple second conversion circuits 2_1 to 2_n, when the second conversion circuits 2_1 to 2_n respectively convert the first voltage Vo1 into second voltages Vo2_1 to Vo2_n of different levels, in addition to the load 200 with the highest voltage demand (i.e., the one with the highest voltage demand) being supplied with the first voltage Vo1 by the first conversion circuit 1, the control circuit 3 further controls the switching switch 6 and the second switching circuits 5_1 to 5_n to supply the second voltages Vo2_1 to Vo2_n of different levels to the corresponding output terminals A_1 to A_n for the load 200 with a lower voltage demand (i.e., the one with a step-down demand). Among them, the second conversion circuits 2_1 to 2_n can be arranged in sequence according to the magnitudes of the second voltages Vo2_1 to Vo2_n. That is, the second voltage Vo2_1 converted by the second conversion circuit 2_1 is necessarily greater than or equal to the second voltage Vo2_n converted by the second conversion circuit 2_n.

[0067] Specifically, when the second conversion circuits 2_1 to 2_n can respectively convert the first voltage Vo1 into second voltages Vo2_1 to Vo2_n of different levels, the control circuit 3 correspondingly controls the second conversion circuits 2 to convert the second voltages Vo2_1 to Vo2_n of different voltage levels, and controls the switching switch 6 and the second switching circuits 5_1 to 5_n to conduct the corresponding paths to supply the second voltages Vo2_1 to Vo2_n that meet the requirements of the load 200 with a lower voltage demand to the corresponding output terminals A_1 to A_n. For Figure 5A example, when the required voltages of the loads 200 coupled to the output terminals A_1, A_2, and A_3 are 9V, 3V, and 5V respectively, the first conversion circuit 1 provides the first voltage Vo1 of 9V, and the control circuit 3 controls the first switching circuit 4 to conduct the path from the first conversion circuit 1 to the output terminal A_1 to supply the first voltage Vo1 of 9V to the output terminal A_1.

[0068] Moreover, the second conversion circuit 2_1 provides a second voltage Vo2_1 of 5V, and the control circuit 3 controls the second switching circuit 5_1 to conduct the path from the second conversion circuit 2_1 to the output terminal A_3, so as to provide the second voltage Vo2_1 of 5V to the output terminal A_3. In addition, the second conversion circuit 2_2 provides a second voltage Vo2_2 of 3V, and the control circuit 3 controls the second switching circuit 5_2 to conduct the path from the second conversion circuit 2_2 to the output terminal A_2, so as to provide the second voltage Vo2_2 of 3V to the output terminal A_2. Therefore, the power supply 100 can provide a required voltage that meets the requirements of the load 200 according to different loads 200.

[0069] In addition, in the above Figure 5A example, when another load 200 is plugged into the output terminal A_n, its operation mode is similar to Figures 4C to 4E . That is to say, the control circuit 3 also first controls the second conversion circuit 2_n to provide a default voltage of 5V, and based on this, handshake communication is performed with the load 200 at the output terminal A_n. Then, it is adjusted according to the required voltage at the output terminal A_n and supplied by the first conversion circuit 1 and the second conversion circuits 2_1 to 2_n. Suppose the required voltage of the load 200 at the output terminal A_n is 6V, then the power supply 100 changes to the second conversion circuit 2_1 to provide a second voltage Vo2_1 of 6V, and the control circuit 3 controls the second switching circuit 5_1 to conduct the path from the second conversion circuit 2_1 to the output terminal A_n, so as to provide the second voltage Vo2_1 of 6V to the output terminal A_n. Then, the second conversion circuit 2_2 provides a second voltage Vo2_2 of 5V, and the second conversion circuit 2_n provides a second voltage Vo2_n of 3V, and the control circuit 3 conducts the corresponding paths to provide the second voltages Vo2_2 and Vo2_n to the corresponding output terminals A_2 and A_3.

[0070] Please refer to Figure 5B the circuit block diagram of the third embodiment of the power supply of the present invention, and also refer to Figures 1 to 5A . Figure 5B The difference between the power supply 100 of the embodiment and the power supply 100 of Figure 5A is that Figure 5B each output terminal A_1 to A_n of the power supply 100 of Figure 5A is coupled to no more than two second switching circuits 5_1 to 5_n (taking the output terminal A_2 as an example, it is coupled to the second switching circuit 5_1 and the second switching circuit 5_2, and taking the output terminal A_1 as an example, it is coupled to the first switching circuit 4 and the second switching circuit 5_1). Therefore, assuming that the output terminals A_1 to A_n are the same as Figure 5A(5), but the number of the second switches Q2 inside each of the second switching circuits 5_1 to 5-n is two. Therefore, Figure 5B The power supply 100 is characterized in that each of the second conversion circuits 2_1 to 2-n only needs to be responsible for supplying part of the output terminals A_1 to A_n.

[0071] Taking the output terminal A_2 as an example, the second conversion circuits responsible for it are 2_1 and 2_2, and the second switching circuits 5_1 and 5_2 responsible for switching the second voltages Vo2_1 and Vo2_2. Therefore, the power supply sources of the output terminal A_2 are the first voltage Vo1, the second voltages Vo2_1 and Vo2_2, and the control circuit 3 can form a power supply path for the output terminal A_2 by controlling the first switching circuit 4, the switching switch 6, and the second switching circuits 5_1 and 5_2. Thus, Figure 5B the power supply 100 can achieve a similar effect with fewer second switches Q2 (two). It is worth mentioning that in an embodiment, since Figure 5A similar. It is worth mentioning that in an embodiment, since Figure 5A , 5B the output terminals A_1 to A_n are multiple, so it includes various possible situations. For example, the required voltages of some or one of the output terminals A_1 to A_n are 20V, and the required voltages of another or some other ones are 5V and 3V. Thus, the first voltage Vo1 must be provided to the output terminals A_1 to A_n with a required voltage of 20V, and the second conversion circuits 2_1 to 2_n must adjust which one supplies the power. In Figure 5A the logic should be provided by the second conversion circuits 2_1 to 2_2, and in Figure 5B the logic needs to confirm the requirement of which output terminal A_1 to A_n to make corresponding switching. Therefore, in summary, due to the numerous possible situations and corresponding operation methods, it can be inferred according to Figures 1 to Figure 5B the operation logic, and no further elaboration will be made here.

[0072] The above description is only a detailed description and diagram of a preferred specific embodiment of the present invention. However, the features of the present invention are not limited thereto and are not intended to limit the present invention. The entire scope of the present invention should be subject to the scope of the patent application. All embodiments that conform to the spirit of the scope of the patent application of the present invention and its similar variations should be included in the scope of the present invention. Any changes or improvements that can be easily thought of by any person skilled in the art within the field of the present invention can be covered by the patent scope of the present case below.

Claims

1. A power supply unit for providing dual power outputs, characterized in that, The power supply includes: a first conversion circuit that converts an input voltage into a first voltage; a second conversion circuit coupled to the first conversion circuit and converting the first voltage into a second voltage; a control circuit coupled to the first conversion circuit and the second conversion circuit; a first switching circuit coupled to the control circuit, the first conversion circuit, a first output terminal, and a second output terminal; a second switching circuit coupled to the control circuit, the first output terminal, and the second output terminal; and a switching switch coupled to the control circuit, the second conversion circuit, and the second switching circuit; wherein, when the control circuit receives a voltage demand at one of the first output terminal and the second output terminal, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the one end and turn off the path of the first conversion circuit to the other end, and controls the switching switch and the second switching circuit to bidirectionally turn off the path of the second conversion circuit to the first output terminal and the second output terminal, so as to prevent the first voltage from being back-fed to the second conversion circuit, or prevent the second voltage from being erroneously supplied to the first output terminal and the second output terminal.

2. The power supply according to claim 1, wherein When the voltage demands at the first output terminal and the second output terminal received by the control circuit are the same, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the first output terminal and the second output terminal, and controls the switching switch and the second switching circuit to bidirectionally turn off the path of the second conversion circuit to the first output terminal and the second output terminal.

3. The power supply according to claim 1, characterized in that, When the voltage demands at the first output terminal and the second output terminal received by the control circuit are different, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the one with the higher voltage demand among the first output terminal and the second output terminal, and turn off the path of the one with the lower voltage demand, and controls the switching switch and the second switching circuit to conduct the path of the second conversion circuit to the one with the lower voltage demand among the first output terminal and the second output terminal, and turn off the path of the one with the higher voltage demand.

4. The power supply according to claim 1, wherein, When the first conversion circuit supplies the first voltage to one of the first output terminal and the second output terminal through the first switching circuit, and the control circuit knows that a load is plugged into the other of the first output terminal and the second output terminal, the control circuit controls the second conversion circuit to supply a default voltage to the other through the switching switch and the second switching circuit for communication, so as to know the voltage demand of the other, and thereby determine whether the power supply source for the other is the first conversion circuit or the second conversion circuit.

5. The power supply according to claim 4, wherein When the voltage demand of the other is the same as that of the one, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the one and the other, and controls the switching switch and the second switching circuit to maintain bidirectionally turning off the path of the second conversion circuit to the one and the other.

6. The power supply according to claim 4, wherein When the voltage requirement of one of them is higher than that of the other, the control circuit controls the first switching circuit to keep the path of the first conversion circuit to that one conducting, and controls the switching switch and the second switching circuit to keep the path of the second conversion circuit to that one off, and controls the first switching circuit to keep the path of the first conversion circuit to the other off, and controls the switching switch and the second switching circuit to conduct the path of the second conversion circuit to the other.

7. The power supply according to claim 4, wherein When the voltage requirement of one of them is lower than that of the other, the control circuit controls the first switching circuit to turn off the path of the first conversion circuit to that one, and controls the switching switch and the second switching circuit to conduct the path of the second conversion circuit to that one, and controls the first switching circuit to conduct the path of the first conversion circuit to the other, and controls the switching switch and the second switching circuit to keep the path of the second conversion circuit to the other off.

8. The power supply according to claim 1, characterized in that, The first switching circuit includes: A plurality of first switches, coupled to the first conversion circuit and the control circuit, and respectively coupled to the first output terminal and the second output terminal; Wherein, the configuration of the junction diodes of the plurality of first switches is reverse-biased in the direction from the first conversion circuit to the first output terminal and the second output terminal.

9. The power supply according to claim 1, wherein The second switching circuit includes: A plurality of second switches, coupled to the switching switch, the control circuit, and respectively coupled to the first output terminal and the second output terminal; Wherein, the configuration of the junction diodes of the plurality of second switches is forward-biased in the direction from the switching switch to the first output terminal and the second output terminal, and the configuration of the junction diode of the switching switch is reverse-biased in the direction from the second conversion circuit to the plurality of second switches.

10. A power supply unit for providing multiple power outputs, characterized in that, The power supply includes: A first conversion circuit that converts an input voltage into a first voltage; A plurality of second conversion circuits, coupled to the first conversion circuit, and convert the first voltage into a plurality of second voltages; A control circuit, coupled to the first conversion circuit and the plurality of second conversion circuits; A first switching circuit, coupled to the control circuit, the first conversion circuit, and a plurality of output terminals; and A plurality of second switching circuits, coupled to the control circuit and the plurality of output terminals; A plurality of switching switches, coupled to the control circuit, and correspondingly coupled to the second conversion circuits and the plurality of second switching circuits; Wherein, when the control circuit receives the same voltage requirement of one of the plurality of output terminals, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the plurality of output terminals, and turn off the path of the first conversion circuit to the remaining terminals, and controls the plurality of switching switches and the plurality of second switching circuits to correspondingly turn off the paths of the plurality of second conversion circuits to the plurality of output terminals to prevent the first voltage from being back-fed to the plurality of second conversion circuits, or the plurality of second voltages from being erroneously provided to the plurality of output terminals.

11. The power supply according to claim 10, wherein When the control circuit receives the same voltage requirements from the multiple output terminals, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the multiple output terminals, and controls the multiple switching switches and the multiple second switching circuits to correspondingly bidirectionally turn off the paths of the multiple second conversion circuits to the multiple output terminals.

12. The power supply according to claim 10, characterized in that, When the control circuit receives different voltage requirements from the multiple output terminals, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the one with the highest voltage requirement among the multiple output terminals, and turn off the paths with voltage requirements lower than the highest one, and controls the multiple switching switches and the multiple second switching circuits to correspondingly conduct the paths of the multiple second conversion circuits to the paths with voltage requirements lower than the highest one, and turn off the paths with higher voltage requirements, so as to correspondingly provide the multiple second voltages to the output terminals with voltage requirements lower than the highest one.

13. The power supply according to claim 11, characterized in that, The multiple output terminals include multiple step-down demanders with voltage requirements lower than the highest one. When the voltage requirements of the multiple step-down demanders are different, the control circuit correspondingly controls the multiple second conversion circuits to convert second voltages of different voltage levels, and by controlling the multiple switching switches and the multiple second switching circuits to conduct the corresponding paths, to provide the second voltages meeting the requirements of the multiple step-down demanders to the output terminals of the multiple step-down demanders.

14. The power supply according to claim 10, characterized in that, When the first conversion circuit provides the first voltage to at least one of the multiple output terminals through the first switching circuit, and the control circuit learns that a load is plugged into at least another one of the multiple output terminals, the control circuit controls the multiple second conversion circuits to provide a default voltage to the at least another one through the multiple switching switches and the multiple second switching circuits for communication, so as to learn the voltage requirement of the at least another one, and accordingly determine whether the power supply source of the at least another one is the first conversion circuit or the multiple second conversion circuits.

15. The power supply according to claim 14, characterized in that, When the voltage requirement of at least one output terminal of the at least another one is the same as the voltage requirement of the at least one of the at least one, the control circuit controls the first switching circuit to conduct the path of the first conversion circuit to the at least one and the at least one output terminal, and controls the multiple switching switches and the multiple second switching circuits to maintain bidirectionally turning off the multiple second conversion circuits to the at least one and the at least one output terminal.

16. The power supply according to claim 14, characterized in that, When the voltage requirement of the at least one is higher than at least one output terminal of the at least another one, the control circuit controls the first switching circuit to maintain conducting the path of the first conversion circuit to the at least one, and controls the multiple switching switches and the multiple second switching circuits to maintain turning off the paths of the multiple second conversion circuits to the at least one, and controls the first switching circuit to maintain turning off the path of the first conversion circuit to the at least one output terminal, and controls the multiple switching switches and the multiple second switching circuits to correspondingly conduct the path of at least one second conversion circuit of the multiple second conversion circuits to the at least one output terminal.

17. The power supply according to claim 14, characterized in that, When the voltage requirement of at least one of them is lower than at least one output terminal of at least the other one, the control circuit controls the first switching circuit to turn off the path of the first conversion circuit to at least one of them, and controls the plurality of switching switches and the plurality of second switching circuits to conduct the path of the second conversion circuit to at least one of them, and controls the first switching circuit to conduct the path of the first conversion circuit to at least one output terminal, and controls the plurality of switching switches and the plurality of second switching circuits to maintain turning off the path of the second conversion circuit to at least one output terminal.

18. The power supply according to claim 10, wherein, The first switching circuit includes: A plurality of first switches, coupled to the first conversion circuit and the control circuit, and respectively coupled to the plurality of output terminals; Wherein, the configuration of the junction diodes of the plurality of first switches is reverse-biased in the direction from the first conversion circuit to the plurality of output terminals.

19. The power supply according to claim 10, wherein, The plurality of second switching circuits respectively include: A plurality of second switches, coupled to the switching switch, the control circuit, and respectively coupled to the plurality of output terminals; Wherein, the configuration of the junction diodes of the plurality of second switches is forward-biased in the direction from the switching switch to the plurality of output terminals, and the configuration of the junction diodes of the switching switch is reverse-biased in the direction from the second conversion circuit to the plurality of second switches.

20. The power supply according to claim 10, wherein Each output terminal is coupled to no more than two second switching circuits, and each second switching circuit includes no more than two second switches.

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