Control circuit of high-power switching power supply

Abstract

The invention discloses a control circuit of a high-power switching power supply, which is characterized in that a protection switch is arranged between an input capacitor of the switching power supply and a switching circuit, and actual input power is obtained by sampling current of the protection switch and input voltage of the switching circuit. A corresponding input power threshold value or output power is obtained according to the magnitude of the output voltage, and the actual input power is compared with the input power threshold value or the output power so as to judge the magnitude of the system efficiency. Through the scheme of the application, the magnitude of the input current can be obtained through the protection switch so as to obtain the magnitude of the input power, the working efficiency of the system can be accurately calculated, and the magnitude of the current or voltage of the system can be adjusted according to the efficiency so as to optimize the working efficiency of the system.

Description

Technical Field

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

[0002] With the rapid increase in computing power from high-power chips, the output current capability of the switching power supplies that power these chips has also increased rapidly. High-power loads are generally powered by high-power output switching power supply circuits. As a result, the number of power switching transistors integrated on the switching power supply board has increased dramatically, reaching hundreds. Therefore, the efficiency of the board needs to be controlled more precisely.

[0003] Existing technologies such as Figure 1 The high-power switching power supply circuit shown often has imprecise control over system efficiency. It typically calculates the actual output power and the theoretical output power, and obtains the system efficiency by comparing the ratio of the two. However, since it does not involve the input power, it cannot effectively improve the system efficiency.

[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 control circuit for a high-power switching power supply, so as to solve the technical problem of low efficiency of high-power switching power supplies in the prior art.

[0006] According to this application, a control circuit for a high-power switching power supply includes an input capacitor, a switching circuit, and a driver for controlling the switching circuit. The input capacitor receives an external input electrical signal and includes an input power acquisition circuit and an efficiency judgment module. A protection switch is provided between the input capacitor and the switching circuit. The input power acquisition circuit obtains the actual input power of the switching circuit by sampling the current of the protection switch and the input voltage of the switching circuit. The efficiency judgment module samples the output voltage of the switching circuit to obtain an output voltage sampling signal. The efficiency judgment module determines whether the efficiency of the switching power supply meets the requirements based on the actual input power and the output voltage sampling signal.

[0007] Preferably, when the efficiency judgment module determines that the efficiency of the switching power supply does not meet the requirements, the protection switch is disconnected.

[0008] Preferably, the efficiency judgment module pre-sets a correspondence table between the output voltage and input power threshold of the switching circuit, and then obtains the corresponding input power threshold based on the output voltage sampling signal of the switching circuit. The efficiency judgment module compares the actual input power with the input power threshold to determine whether the efficiency of the switching power supply meets the requirements.

[0009] Preferably, the output current of the switching circuit is a predetermined value, and the calculated output power is obtained by multiplying the output voltage sampling signal of the switching circuit and the predetermined output current. The corresponding input power threshold is obtained by looking up the calculated output power value and a pre-set correspondence table.

[0010] Preferably, the efficiency judgment module obtains the actual output power based on the output voltage sampling signal of the switching circuit, obtains an efficiency ratio signal based on the ratio of the actual output power to the actual input power, and compares the efficiency ratio signal with an efficiency threshold to determine whether the efficiency of the switching power supply meets the requirements.

[0011] Preferably, the output current of the switching circuit is a predetermined value, and the actual output power is obtained by multiplying the output voltage sampling signal of the switching circuit with the predetermined output current.

[0012] Preferably, the input power acquisition circuit includes a current sampling circuit, a voltage sampling circuit, and a multiplier. The current sampling circuit samples the current of the protection switch to obtain an input current sampling signal, the voltage sampling circuit samples the input voltage of the switch circuit to obtain an input voltage sampling signal, and the multiplier receives the input current sampling signal and the input voltage sampling signal to obtain the actual input power of the switch circuit.

[0013] Preferably, the efficiency judgment module samples the voltage of the switching node of the switching circuit, filters the switching node voltage to obtain the output voltage sampling signal, wherein the switching circuit includes a bridge switch and an inductor, the switching node is the intermediate connection point of the bridge switch, and the intermediate connection point is connected to one end of the inductor.

[0014] Preferably, the control circuit further includes a leakage current detection circuit, and the switching circuit includes a bridge switching transistor composed of an upper switching transistor and a lower switching transistor. The leakage current detection circuit detects the operating current of the upper switching transistor or the lower switching transistor, and when its operating current is greater than the corresponding set threshold current, it controls the protection switch to turn off.

[0015] Preferably, the leakage current detection circuit includes a first sampling circuit, a second sampling circuit, and an OR gate. The first sampling circuit samples the operating current of the upper switching transistor to obtain a first sampling signal; the second sampling circuit samples the operating current of the lower switching transistor to obtain a second sampling signal; the OR gate receives the first sampling signal and the second sampling signal to output a first logic signal. When the first logic signal is in a high-level active state, the protection switch is turned off.

[0016] The control scheme for a high-power switching power supply of this invention involves placing a protective switch between the input capacitor and the switching circuit of the switching power supply. The actual input power is obtained by sampling the current of the protective switch and the input voltage of the switching circuit. A corresponding input power threshold is obtained based on the output voltage. The actual input power and the input power threshold are compared to determine the system efficiency. This scheme allows the input current to be obtained through the protective switch, thereby determining the input power and enabling accurate calculation of the system's operating efficiency. The current or voltage of the system can then be adjusted based on the efficiency, thus optimizing the system's operating efficiency. Attached Figure Description

[0017] Figure 1 A circuit block diagram of a prior art switching power supply;

[0018] Figure 2 This is a circuit block diagram of a first embodiment of the control circuit for a high-power switching power supply according to the present invention;

[0019] Figure 3 This is a circuit block diagram of a second embodiment of the control circuit for a high-power switching power supply according to the present invention;

[0020] Figure 4 This is a circuit block diagram of a third embodiment of the control circuit for a high-power switching power supply according to the present invention. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] The invention is described more specifically in the following paragraphs 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.

[0024] refer to Figure 2 Here is a circuit block diagram of a first embodiment of the control 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 (upper switching transistor), Q2 (lower switching transistor), 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 switching power supply also includes a protection switch M1, which is connected between the input terminal and the switching circuit. The protection switch can be a field-effect transistor (FET) or other suitable switching transistor. In this embodiment, an FET is used as an example. In this embodiment, the protection switch M1 is also driven by the driver. When the protection switch M1 is turned on, the switching circuit receives the electrical signal from the input terminal, processes it, and generates an output voltage. In this embodiment, one end of the input capacitor Cin is connected to a node on the path from the input electrical signal to the input terminal, and the other end is connected to a reference ground. External input electrical signals, such as voltage, are processed by the input capacitor and transmitted to the input terminal.

[0025] Continue to refer to Figure 2 The control circuit in this embodiment includes an input power acquisition circuit and an efficiency judgment module. In this embodiment, the input power acquisition circuit includes a current sampling circuit, a voltage sampling circuit, and a multiplier. The current sampling circuit samples the current of the protection switch (e.g., ...). Figure 2 The sampling circuit obtains the input current sampling signal by sampling the current at the right end of the sampling protection switch (e.g., the voltage sampling circuit samples the input voltage of the switching circuit). Figure 2 The input voltage is obtained by receiving the input current sampling signal and the input voltage sampling signal, and the multiplier receives the input current sampling signal and the input voltage sampling signal to obtain the actual input power Pin of the switching circuit. Here, the current sampling circuit can be a resistor or a current mirror sampling circuit, the voltage sampling circuit can be a voltage divider resistor sampling method, and the multiplier can be an existing multiplier circuit structure.

[0026] refer to Figure 2As shown, the efficiency judgment module in this embodiment includes an input power threshold circuit and a power comparison circuit. In this example, the efficiency judgment module pre-sets a correspondence table between the output voltage of the switching circuit and the input power threshold, and then obtains the corresponding input power threshold based on the actual magnitude of the output voltage of the switching circuit. Specifically: since the output current of the switching circuit is a predetermined magnitude, the output power can be obtained simply by obtaining the magnitude of the output voltage, given the magnitude of the output current. The input power threshold module samples the voltage of the switching node of the switching circuit, filters the switching node voltage to obtain the output voltage sampling signal (the output voltage sampling signal can characterize the magnitude of the actual output voltage). The filtering circuit can be a circuit structure of resistors and capacitors. Then, the calculated output power Pin is obtained by multiplying the output voltage sampling signal of the switching circuit and the predetermined output current. The corresponding input power threshold Pin_ref is obtained by looking up the calculated output power and the pre-set correspondence table. Here, the switching node is the intermediate connection point of the bridge switch, which is connected to one end of the inductor, such as... Figure 2 The SW node in the circuit. The power comparison circuit can be implemented using a comparator. The signal output by the power comparison circuit is sent to the control drive circuit, which generates a switching signal to control the switching action of the protection switch.

[0027] The efficiency judgment circuit receives the actual input power and the input power threshold, compares the actual input power with the power threshold to determine whether the efficiency of the switching power supply meets the requirements. Furthermore, when the efficiency judgment module determines that the efficiency of the switching power supply does not meet the requirements, it disconnects the protection switch M1. For example, if the actual output power corresponds to an input power of a certain threshold Pin_ref1, and the actual input power is greater than this threshold, it indicates that the input power is too high and needs to be reduced. Therefore, disconnecting the protection switch stops the input energy, reducing the input power and thus improving the system efficiency. Through the above control method, the system efficiency can be effectively controlled, maintaining a high operating efficiency and avoiding energy waste.

[0028] For reference Figure 3The second embodiment of the control circuit for a high-power switching power supply according to the present invention is shown. The input power acquisition module in this embodiment is the same as in the previous embodiment, except that the efficiency judgment module includes an output power circuit and an efficiency judgment circuit. The actual output power Pin is obtained based on the output voltage of the switching circuit. Specifically, the output current of the switching circuit is a predetermined value. The output power circuit obtains the actual output power Pout based on the product of the actual output voltage and the predetermined output current. Similarly, the voltage of the switching node SW is filtered to obtain the output voltage sampling signal (which can represent the actual output voltage value). Then, the efficiency judgment circuit obtains an efficiency ratio signal based on the ratio of the actual output power Pout to the actual input power Pin. The efficiency ratio signal is compared with an efficiency threshold to determine whether the efficiency of the switching power supply meets the requirements. For example, if the ratio of the actual output power Pout to the actual input power Pin is large, exceeding the set efficiency threshold, it indicates excessive input power. In this case, by opening the protection switch, the input energy is stopped, reducing the input power and thus improving the system efficiency. The efficiency threshold can be predetermined according to the needs of the working environment, such as being set to a value between 0.9 and 1. Similarly, this embodiment, through the control method described above, can effectively control the system efficiency, maintain a high working efficiency, and avoid energy waste.

[0029] Preferably, refer to Figure 4 The control circuit of the high-power switching power supply in this application also includes a leakage current detection circuit. The leakage current detection circuit includes a first sampling circuit, a second sampling circuit, and a logic OR gate. The first sampling circuit samples the operating current of the upper switching transistor to obtain a first sampling signal. The second sampling circuit samples the operating current of the lower switching transistor to obtain a second sampling signal. The OR gate receives the first sampling signal and the second sampling signal to output a first logic signal. When the first logic signal is in a high-level active state, the protection switch M1 is turned off. Here, the first and second sampling circuits can be sampling methods using resistors or current mirrors, or other sampling methods. Through the leakage current detection of this embodiment, in the event of a switch transistor failure, such as an upper switching transistor failure, but the lower switching transistor generates a relatively large negative current during operation, when this current is detected to be greater than a certain threshold, the lower switching transistor can be prevented from being damaged by timely disconnection of the protection switch M1, thus protecting the power switching transistor in the protection circuit.

[0030] Preferably, in this embodiment, the control circuit, the switching circuit, and the driver of the switching power supply are all integrated into a single chip, wherein the input terminal corresponds to the input pin of the chip. The solution of this application integrates the protection switch, improving system integration and intelligent control. The switching power supply of this application can also be extended to multi-channel switching circuits, all of which can achieve optimal system efficiency and best safety through the aforementioned efficiency control and leakage detection methods.

[0031] The circuit described above includes a protective switch between the input capacitor and the switching circuit of the switching power supply. The actual input power is obtained by sampling the current of the protective switch and the input voltage of the switching circuit. The corresponding input power threshold or output power is obtained based on the sampled output voltage signal. The actual input power is compared with the input power threshold, or the actual output power is compared with the actual input power, to determine the system efficiency. This solution allows the input current to be obtained through the protective switch, thereby determining the input power and accurately calculating the system's efficiency. The input energy supply can then be adjusted based on the efficiency, thus optimizing the system's performance. The comparison between the actual input power and output power also includes variations, such as comparing input power and output power, all of which are within the scope of this application.

[0032] Similarly, the structure of the switching circuit can also include a first capacitor, such as capacitor C1. 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 inside a chip.

[0033] 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.

[0034] 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 described embodiment can be referred to.

[0035] 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 control 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, wherein the input capacitor receives an external input electrical signal, characterized in that, Includes an input power acquisition circuit and an efficiency judgment module. A protective switch is provided between the input capacitor and the switching circuit of the switching power supply. The input power acquisition circuit obtains the actual input power of the switching circuit by sampling the current of the protection switch and the input voltage of the switching circuit. The efficiency judgment module samples the output voltage of the switching circuit to obtain an output voltage sampling signal. The efficiency judgment module determines whether the efficiency of the switching power supply meets the requirements based on the actual input power and the output voltage sampling signal.

2. The control circuit of the high-power switching power supply according to claim 1, characterized in that, When the efficiency judgment module determines that the efficiency of the switching power supply does not meet the requirements, it disconnects the protection switch.

3. The control circuit of the high-power switching power supply according to claim 1, characterized in that, The efficiency judgment module pre-sets a correspondence table between the output voltage and input power threshold of the switching circuit, and then obtains the corresponding input power threshold based on the output voltage sampling signal of the switching circuit. The efficiency judgment module compares the actual input power with the input power threshold to determine whether the efficiency of the switching power supply meets the requirements.

4. The control circuit of the high-power switching power supply according to claim 3, characterized in that, The output current of the switching circuit is a predetermined value. The calculated output power is obtained by multiplying the output voltage sampling signal of the switching circuit with the predetermined output current. The corresponding input power threshold is obtained by looking up the calculated output power and a pre-set correspondence table.

5. The control circuit of the high-power switching power supply according to claim 1, characterized in that, The efficiency judgment module obtains the actual output power based on the output voltage sampling signal of the switching circuit. The efficiency judgment module obtains an efficiency ratio signal based on the ratio of actual output power to actual input power. The efficiency ratio signal is compared with an efficiency threshold to determine whether the efficiency of the switching power supply meets the requirements.

6. The control circuit of the high-power switching power supply according to claim 5, characterized in that, The output current of the switching circuit is a predetermined value, and the actual output power is obtained by multiplying the output voltage sampling signal of the switching circuit with the predetermined output current.

7. The control circuit of the high-power switching power supply according to claim 1, characterized in that, The input power acquisition circuit includes a current sampling circuit, a voltage sampling circuit, and a multiplier. The current sampling circuit samples the current of the protection switch to obtain an input current sampling signal. The voltage sampling circuit samples the input voltage of the switching circuit to obtain an input voltage sampling signal. The multiplier receives the input current sampling signal and the input voltage sampling signal to obtain the actual input power of the switching circuit.

8. The control circuit of the high-power switching power supply according to claim 1, characterized in that, The efficiency judgment module samples the voltage of the switching nodes of the switching circuit and filters the switching node voltage to obtain the output voltage sampling signal. The switching circuit includes a bridge switch and an inductor, and the switching node is the middle connection point of the bridge switch, which is connected to one end of the inductor.

9. The control circuit of the high-power switching power supply according to claim 1, characterized in that, The control circuit also includes a leakage current detection circuit. The switching circuit includes a bridge switching transistor consisting of an upper switching transistor and a lower switching transistor. The leakage current detection circuit detects the operating current of the upper or lower switch transistor. When its operating current exceeds the corresponding set threshold current, it controls the protection switch to turn off.

10. The control circuit of the high-power switching power supply according to claim 9, characterized in that, The leakage current detection circuit includes a first sampling circuit, a second sampling circuit, and an OR gate. The first sampling circuit samples the operating current of the upper switching transistor to obtain a first sampling signal; The second sampling circuit samples the operating current of the lower switching transistor to obtain a second sampling signal; The OR gate receives the first sampling signal and the second sampling signal to output a first logic signal. When the first logic signal is in a high-level active state, the protection switch is turned off.

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