Protection circuit of high-power switching power supply and multi-path switching power supply

Abstract

The invention discloses a protection circuit of a high-power switching power supply and a multi-path switching power supply, a protection switch is arranged between an input capacitor of the switching power supply and a switching circuit, and when the switching power supply is abnormal, the protection switch is switched off so as to protect the switching power supply. In the multi-path switching power supply, a protection switch is arranged between an input capacitor of a power level circuit of each path and a switching circuit, and when a certain path is abnormal, the protection switch of the path is switched off so as to protect the circuit structure of the path. According to the scheme of the invention, since the protection switch is arranged behind the input capacitor, the stress demand of the protection switch can be greatly reduced, and the cost and area of the protection switch are reduced.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and more specifically, to a protection circuit for a high-power switching power supply and a multi-channel switching power supply. Background Technology

[0002] With the rapid increase in computing power provided by high-power chips, the output current capability of the switching power supplies that power these chips has also increased rapidly. Typically, multiple switching power supply circuits are needed to power high-power chips. Therefore, the number of power switching transistors integrated on a single switching power supply board has increased dramatically, sometimes reaching hundreds. Consequently, various problems associated with these boards have also multiplied. If any power switching transistor in any circuit short-circuits, it can transfer the input voltage to the load side, causing overvoltage damage and ultimately leading to system board failure.

[0003] Existing technologies such as Figure 1 The multi-channel switching power supply circuit shown uses an electronic switch, such as switch S1, added to the input terminal on the input side. This switch is positioned between the input terminal and the input capacitors of each switching power supply. When a short circuit occurs at the output, the electronic switch is disconnected to cut off the power supply to the input side, protecting the system board from being burned out. However, this circuit suffers from slow response, high switching stress, and the risk of the entire power supply losing power if any one of the circuits fails.

[0004] Therefore, it is necessary to provide improved technical solutions to overcome the above-mentioned technical problems existing in the prior art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a protection circuit for a high-power switching power supply and a multi-channel switching power supply, so as to solve the technical problems of slow response and overall circuit power failure in the prior art of high-power switching power supplies.

[0006] According to this application, a protection circuit for a high-power switching power supply includes an input capacitor, a switching circuit, and a driver for controlling the switching circuit. The protection circuit includes a protection switch connected between the input terminal and the switching circuit. An external input voltage is processed by the input capacitor and then transmitted to the input terminal. The driver detects the operating status of the switching power supply, and when a fault is detected in the switching power supply, it controls the protection switch to open.

[0007] Preferably, the switching circuit includes a bridge switch and an inductor. When the protection switch is turned on, the switching circuit receives the signal from the input terminal and generates an output voltage after processing by the switching circuit.

[0008] Preferably, the upper switch in the bridge switch is a high-voltage switch and the lower switch is a low-voltage switch, and the voltage / current withstand capability of the protection switch is lower than that of the upper switch.

[0009] Preferably, during the startup process of the switching power supply, the driver first controls the protection switch to turn on, and then controls the switching circuit to enter the working state; during the shutdown process of the switching power supply, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off.

[0010] Preferably, during normal operation, the driver detects the voltage across the protective switch. If the voltage across the protective switch is higher than a preset value, the power supply is determined to have malfunctioned.

[0011] Preferably, the protection switch, the switching circuit, and the driver are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip.

[0012] Secondly, according to this application, a multi-channel switching power supply includes a multi-channel switching circuit, wherein the plurality of switching circuits respectively receive input signals to generate multiple output signals, and the multiple output signals all supply power to a load. The multi-channel switching circuit is characterized in that each channel includes an input capacitor, a protection switch, a switching circuit, and a driver for controlling the switching circuit. The protection switch is connected between the input terminal and the switching circuit. An external input voltage is processed by the input capacitor and transmitted to the input terminal. The driver detects the operating state of the switching power supply, and when a fault is detected in the switching power supply, it controls the protection switch to open.

[0013] Preferably, each of the switching circuits includes a bridge switch and an inductor. When the protection switch is turned on, the switching circuit receives the signal from the input terminal, processes it, and generates a corresponding output voltage.

[0014] Preferably, the upper switch in the bridge switch is a high-voltage switch and the lower switch is a low-voltage switch, and the withstand voltage of the protection switch is the same as that of the lower switch.

[0015] Preferably, during the startup process of one circuit of the switching power supply, the driver first controls the protection switch to turn on, and then controls the switching circuit to enter the working state; during the shutdown process of one circuit of the switching power supply, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off.

[0016] Preferably, during normal operation, the driver of each path detects the voltage across the protection switch. When the voltage across the protection switch of a certain path is higher than a preset value, it is determined that a fault has occurred in that path.

[0017] Preferably, when a fault occurs in one of the multiple switching power supplies, the corresponding protection switch for that power supply is disconnected, while the remaining power supplies continue to operate normally.

[0018] Preferably, the input capacitor is connected between the transmission end of the input signal and the input end, and the input capacitor is used to stabilize the signal transmitted to the input end.

[0019] Preferably, the protection switch, the switching circuit, and the driver of the multi-channel switching power supply are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip.

[0020] Preferably, each channel of the multi-channel switching power supply further includes a first capacitor, which is connected between the protection switch and the switching circuit, and the capacitance of the first capacitor is much smaller than the capacitance of the input capacitor.

[0021] The protection scheme for a high-power switching power supply according to this invention involves setting a protection switch between the input capacitor and the switching circuit of the switching power supply. When an abnormality occurs in the switching power supply, the protection switch is disconnected, thereby protecting the switching power supply. In a multi-channel switching power supply, a protection switch is set between the input capacitor and the switching circuit of each channel's power stage circuit. When an abnormality occurs in a certain channel, the protection switch of that channel is disconnected, thereby protecting the circuit structure of that channel. With the scheme of this application, since the protection switch is located after the input capacitor, the stress requirement of the protection switch can be greatly reduced, while also reducing the cost and area of ​​the protection switch. Attached Figure Description

[0022] Figure 1 A circuit block diagram of a prior art switching power supply;

[0023] Figure 2 A first circuit block diagram of a protection circuit for a high-power switching power supply according to the present invention;

[0024] Figure 3 This is a second circuit block diagram of a protection circuit for a high-power switching power supply according to the present invention.

[0025] Figure 4 A circuit block diagram of a multi-channel switching power supply according to the present invention. Detailed Implementation

[0026] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the present invention.

[0027] To provide the public with a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the invention, but those skilled in the art can fully understand the invention without these details.

[0028] The invention is described in more detail below by way of example with reference to the accompanying drawings. It should be noted that the drawings are in a simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0029] refer to Figure 2 Here is a circuit block diagram of a protection circuit for a high-power switching power supply according to the present invention, as shown below. Figure 2 As shown, the switching power supply includes an input capacitor Cin, a switching circuit (the switching circuit includes bridge switching transistors Q1 and Q2 and an inductor L1), and a driver for controlling the switching circuit. The driver is mainly used to drive the switching action of the bridge switching transistors. Figure 2 As shown, the protection circuit includes a protection switch M1, which can be a field-effect transistor (FET) or other suitable switching transistor. In this embodiment, an FET is used as an example. The protection switch M1 is connected between the input terminal and the switching circuit. When the protection switch M1 is turned on, the switching circuit receives the signal from the input terminal and generates an output voltage after processing. In this embodiment, one end of the input capacitor is connected to a node on the path from the input signal to the input terminal, and the other end is connected to a reference ground. The external input voltage is processed by the input capacitor and then transmitted to the input terminal.

[0030] like Figure 2 As shown, the driver detects the operating status of the switching power supply. When a fault is detected in the switching power supply, it controls the protection switch M1 to open. During normal operation, the driver detects the voltage across the protection switch. When the voltage across the protection switch is higher than a preset value, it determines that the switching power supply has failed. In this embodiment, both the switching circuit and the protection circuit are driven and controlled by the driver. For example, the driver detects the drain-source voltage difference across transistor M1. When the voltage difference is greater than a preset value, it indicates a short-circuit fault in the switching circuit. At this time, the driver controls the protection switch M1 to open, thereby disconnecting the switching circuit from the input voltage and protecting the power switching transistor or load of the switching circuit from damage.

[0031] Preferably, the upper switch in the bridge switching transistor is a high-voltage switch, and the lower switch is a low-voltage switch. The voltage / current withstand capability of the protection switch is lower than that of the upper switch. In high-power switching power supplies, a large output current is required. Therefore, the main power switch in the switching circuit, such as the upper switch, needs to withstand a relatively large current, requiring high voltage and current withstand capabilities. In this application, by connecting the protection switch between the input terminal and the input terminal of the switching circuit, its withstand voltage only needs to cover the current of the parasitic capacitance of the upper and lower switches. Its withstand voltage is very low, and its level can be the same as that of the lower switch. Existing technology uses high-voltage switches connected between the input capacitor and the input signal. The protection switch in this application has lower requirements for switching characteristics, reducing the switch size and thus saving overall cost and area.

[0032] like Figure 2 The switching power supply shown in the diagram, during its startup process, first controls the protection switch to turn on, and then controls the switching circuit to enter the working state; conversely, during the shutdown process, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off. In this way, during the startup and shutdown processes, the normal operation of the switching circuit can be guaranteed, while minimizing the switching stress on the protection switch M1.

[0033] Preferably, in this embodiment, the protection switch, the switching circuit, and the driver are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip. Since the input capacitor Cin performs voltage regulation and filtering on the input signal, the input capacitor can consist of multiple capacitors, and therefore its capacitance value is generally large. It is located outside the chip. In existing technologies, the protection switch is connected before the input capacitor, thus preventing its integration. In this application, by connecting the protection switch after the input capacitor and significantly reducing its withstand voltage, its withstand voltage is lower, allowing for integration into the chip. The solution presented in this application has higher chip integration and better intelligence.

[0034] refer to Figure 3 This is a second circuit block diagram of the protection circuit for a high-power switching power supply according to the present invention; this embodiment and Figure 2 The basic structure is similar, except that in this embodiment, a first capacitor is connected between the protection switch and the switching circuit. The capacitance of the first capacitor is much smaller than that of the input capacitor; for example, the capacitance of the first capacitor is one-thousandth of the capacitance of the input capacitor, or the capacitance of the first capacitor is in the nanofarad range while that of the input capacitor is in the microfarad range. Thus, the first capacitor can filter and decouple the signal input to the switching circuit. Due to its small capacitance, the first capacitor is small enough to be integrated into a chip.

[0035] refer to Figure 4 The present invention provides a circuit block diagram of a multi-channel switching power supply. The multi-channel switching power supply includes multiple switching circuits, each receiving an input signal Vin (e.g., input voltage) to generate multiple output signals, such as output current and output voltage. In this embodiment, all multiple output signals supply power to the load for high-current, high-power electrical energy. Figure 3 As shown, each channel of the multi-channel switching circuit includes an input capacitor Cin, a protection switch M1, a switching circuit, and a driver for controlling the switching circuit. The driver for each channel is used to drive the protection switch M1 and the switching transistor in the corresponding channel's switching circuit.

[0036] like Figure 3 As shown, in each channel of the switching power supply, the protection switch M1 is connected between the input terminal and the switching circuit. The external input voltage is processed by the input capacitor Cin and then transmitted to the input terminal. The input capacitor Cin is connected between the input signal transmission terminal and the input terminal. The input capacitor is used to stabilize the signal transmitted to the input terminal. Here, the capacitance value of the input capacitor is relatively large.

[0037] Each switching circuit includes a bridge switching transistor and an inductor, such as an upper switching transistor Q1 and a lower switching transistor Q2, and an inductor L1. When the protection switch is turned on, the switching circuit receives the signal from the input terminal, processes it, and generates a corresponding output voltage. Preferably, the upper switching transistor in the bridge switching transistor is a high-voltage switching transistor, and the lower switching transistor is a low-voltage switching transistor. The voltage / current withstand capability of the protection switch is lower than that of the upper switching transistor. Since high-power switching power supplies require a large output current, the main power switching transistor in the switching circuit, such as the upper switching transistor, needs to withstand a relatively large current and has a high withstand voltage. In this application, by connecting the protection switch between the input terminal and the input terminal of the switching circuit, its withstand voltage only needs to cover the current of the parasitic capacitance of the upper and lower switching transistors; its withstand voltage is very small, and its level can be the same as the withstand voltage of the lower switching transistor. Compared with existing solutions, this application can significantly reduce the characteristic requirements of the protection switch, reducing cost and area.

[0038] like Figure 3As shown, the protection switch M1 is connected between the input terminal and the path of the switching circuit. The driver detects the operating status of the switching power supply. When a fault is detected in the switching power supply, the driver controls the protection switch to open. The protection switch M1 can be a field-effect transistor (FET) or other suitable switching transistor. In this embodiment, an FET is used as an example, and the upper and lower switching transistors in the switching circuit are also FETs. During normal operation of the switching power supply, the driver detects the voltage across the protection switch. When the voltage across the protection switch is higher than a preset value, the driver determines that the switching power supply has failed. The preset value can be an overvoltage threshold. For example, the driver detects the drain-source voltage difference across transistor M1. When the voltage difference is greater than the preset value, it indicates a short circuit fault in the switching circuit. At this time, the driver controls the protection switch M1 to open, thereby disconnecting the switching circuit from the input voltage and protecting the power switching transistor or load of the switching circuit from damage.

[0039] Preferably, during the startup process of one of the multiple switching power supplies, the driver first controls the protection switch to turn on, and then controls the switching circuit to enter the working state; during the shutdown process of one of the switching power supplies, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off. In a multiple switching power supply, depending on the power consumption of the load, it may be necessary to add a switching circuit to work, or reduce the number of switching circuits to stop working. The above method allows for the sequential and safe switching of each switching circuit, and reduces the requirements for the protection switch.

[0040] In this invention, when a fault occurs in one of the multiple switching power supplies, the corresponding protection switch is disconnected, while the remaining power supplies continue to operate normally. This allows for a quick disconnection of the faulty power supply from the system bus voltage when a fault occurs, without affecting the operation of the other power supplies, maintaining the output voltage, and preventing damage to the load.

[0041] Preferably, in this embodiment, the protection switch, the switching circuit, and the driver of the multi-channel switching power supply are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip. In the prior art, the input capacitor cannot be integrated due to its large capacitance value, and therefore the protection switch connected before the input capacitor cannot be integrated either. The solution of this application can integrate the protection switch, improving system integration and intelligent control. The multi-channel switching power supply of this application can include multiple sub-switching circuit units, and each sub-switching circuit unit can include multiple channels. Therefore, even if the number of switching transistors reaches hundreds or more, the operation of each channel is not affected by other channels, and all can be highly integrated.

[0042] Similarly, for a multi-channel switching power supply, each channel can also include a first capacitor. This first capacitor is connected between the protection switch and the switching circuit. The capacitance of the first capacitor is much smaller than the capacitance of the input capacitor, for example, one-thousandth of the capacitance of the input capacitor. In this way, the first capacitor can filter and decouple the signal input to the switching circuit. Due to its small capacitance, the first capacitor is small enough to be integrated into a chip.

[0043] It should be noted that the specific implementations and corresponding illustrations provided are merely one way of describing the implementation method of the present invention, and are not intended to limit the specific structure of the implementation scheme of the present invention. Various changes or modifications can be made to these implementation schemes without departing from the principles and essence of the present invention, but all such changes and modifications fall within the protection scope of the present invention.

[0044] Although the embodiments are described and illustrated separately above, some common technologies are involved. Those skilled in the art can replace and integrate them between the embodiments. If there is any content not explicitly described in one embodiment, then another embodiment that is described can be referred to.

[0045] The embodiments described above do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the above embodiments should be included within the scope of protection of this technical solution.

Claims

1. A protection circuit for a high-power switching power supply, the switching power supply comprising an input capacitor, a switching circuit, and a driver for controlling the switching circuit, characterized in that, The protection circuit includes a protection switch. The protection switch is connected between the input terminal and the switching circuit. The external input voltage is processed by the input capacitor and then transmitted to the input terminal. The driver detects the operating status of the switching power supply, and when a fault is detected in the switching power supply, it controls the protection switch to open.

2. The protection circuit for the high-power switching power supply according to claim 1, characterized in that, The switching circuit includes a bridge switch and an inductor. When the protection switch is turned on, the switching circuit receives the signal from the input terminal, and after processing by the switching circuit, generates an output voltage.

3. The protection circuit for the high-power switching power supply according to claim 2, characterized in that, The upper switch in the bridge-type switching transistor is a high-voltage switch, and the lower switch is a low-voltage switch. The voltage / current withstand capability of the protection switch is lower than that of the upper switch tube.

4. The protection circuit for the high-power switching power supply according to claim 1, characterized in that, During the startup process of the switching power supply, the driver first controls the protection switch to turn on, and then controls the switching circuit to enter the working state. During the process of the switching power supply stopping, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off.

5. The protection circuit for the high-power switching power supply according to claim 1, characterized in that, During normal operation, the driver detects the voltage across the protection switch. When the voltage across the protection switch is higher than a preset value, it is determined that the power supply has failed, and the driver controls the protection switch to open.

6. The protection circuit for the high-power switching power supply according to claim 1, characterized in that, The protection switch, the switching circuit, and the driver are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip.

7. The protection circuit for a high-power switching power supply according to claim 6, characterized in that, A first capacitor is also connected between the protection switch and the switching circuit. The capacitance of the first capacitor is much smaller than the capacitance of the input capacitor.

8. A multi-channel switching power supply, comprising multiple switching circuits, wherein each switching circuit receives an input signal to generate multiple output signals, all of which supply power to a load, characterized in that, Each channel of the multiplexer circuit includes an input capacitor, a protection switch, a switching circuit, and a driver for controlling the switching circuit. The protection switch is connected between the input terminal and the switching circuit. The external input voltage is processed by the input capacitor and then transmitted to the input terminal. The driver detects the operating status of the switching power supply, and when a fault is detected in the switching power supply, it controls the protection switch to open.

9. The multi-channel switching power supply according to claim 8, characterized in that, Each of the switching circuits includes a bridge switch and an inductor. When the protection switch is turned on, the switching circuit receives the signal from the input terminal, and after processing by the switching circuit, generates a corresponding output voltage.

10. The multi-channel switching power supply according to claim 9, characterized in that, The upper switch in the bridge-type switching transistor is a high-voltage switch, and the lower switch is a low-voltage switch. The voltage / current withstand capability of the protection switch is lower than that of the upper switch tube.

11. The multi-channel switching power supply according to claim 8, characterized in that, During the startup process of one of the switching power supplies, the driver first controls the protection switch to turn on, and then controls the switching circuit to enter the working state. During the process of one of the circuits of the switching power supply stopping operation, the driver first controls the switching circuit to stop working, and then controls the protection switch to turn off.

12. The multi-channel switching power supply according to claim 8, characterized in that, During normal operation, the driver of each channel detects the voltage across the protection switch. When the voltage across the protection switch of a certain channel is higher than a preset value, it is determined that a fault has occurred in that channel.

13. The multi-channel switching power supply according to claim 12, characterized in that, When a fault occurs in one of the multiple switching power supplies, the corresponding protection switch for that power supply is disconnected, while the other power supplies continue to operate normally.

14. The multi-channel switching power supply according to claim 8, characterized in that, The input capacitor is connected between the input signal transmission terminal and the input terminal, and is used to regulate the input voltage transmitted to the input terminal.

15. The multi-channel switching power supply according to claim 8, characterized in that, The protection switch, the switching circuit, and the driver of the multi-channel switching power supply are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip.

16. The multi-channel switching power supply according to claim 15, characterized in that, Each channel of the multi-channel switching power supply also includes a first capacitor, which is connected between the protection switch and the switching circuit. The capacitance of the first capacitor is much smaller than that of the input capacitor.

Images