Current sharing circuit of multiphase interleaved switching power supply

Abstract

The utility model discloses a current sharing circuit of a multi-phase interleaved switching power supply, which comprises an outer loop control circuit, a voltage division circuit, a plurality of average current loop control circuits and a plurality of peak current-limiting protection circuits, and is characterized in that the output end of the outer loop control circuit is connected with the input end of the voltage division circuit; the output end of the voltage division circuit is respectively connected with the input ends of the plurality of average current loop control circuits, and the average current loop control circuits are connected with the peak current-limiting protection circuit. According to the utility model, double-loop control of the voltage loop and the current loop is adopted, the output of the outer loop control circuit is used as an instruction of the mean value current loop control circuit through the action of the voltage division circuit, current instructions obtained by each phase are the same, and the mean value current loop control circuit adopts a mean value control mode. The average value of the actual current of each phase is close to the average value of the instruction current, the current difference between the phases is small, and the current sharing of the control circuit can be ensured and the safe work of the circuit can be ensured in cooperation with respective peak current protection.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supplies, and more specifically to a current sharing circuit of a multi-phase interleaved switching power supply. Background Art

[0002] In the power supply design of electronic equipment, switching power supply has become the mainstream choice in the field of power electronics today due to its high efficiency, small size and fast response. However, with the rapid development of science and technology, especially in the fields of communications, data centers, industrial control, etc., the requirements for power supply performance are getting higher and higher, especially the demand for large current output and low ripple noise is becoming more and more urgent.

[0003] Traditional single-phase switching power supplies face many challenges when used in high-current applications. First, due to the rated current limit of the single-phase switch tube, it is difficult for it to directly bear excessive current loads, which will cause the switch tube to overheat or even damage, greatly limiting the stability and reliability of the power supply. Second, the output ripple of the single-phase power supply is large, which will have an adverse effect on the performance and stability of electronic equipment, especially in precision instruments and communication equipment that are sensitive to noise.

[0004] In order to solve the above problems, multi-phase interleaved switching power supply technology came into being. Multi-phase interleaved switching power supply distributes the total current to multiple phases by increasing the number of switching tubes. Each phase only needs to handle a relatively small part of the current, thus avoiding the overheating and damage caused by the single-phase switching tube bearing too much current. At the same time, the multi-phase interleaved design can also effectively reduce the output ripple and improve the stability and performance of the power supply.

[0005] In a multi-phase interleaved switching power supply, the current of each phase needs to be maintained at a relatively balanced level. However, it is difficult to maintain a balanced current in each phase of the existing multi-phase interleaved switching power supply. If the current of one phase is too large and the current of other phases is too small, the switch tube of the phase with large current will heat up seriously or even be damaged, thus affecting the reliability and stability of the entire power supply system. Utility Model Content

[0006] In order to overcome the problem that the current of each phase of the existing multi-phase interleaved switching power supply is difficult to maintain balance, the utility model provides a current balancing circuit of the multi-phase interleaved switching power supply.

[0007] The technical solution of the utility model is as follows:

[0008] A current balancing circuit for a multi-phase interleaved switching power supply comprises an outer loop control circuit, a voltage divider circuit, a plurality of mean current loop control circuits and a plurality of peak current limiting protection circuits, wherein the output end of the outer loop control circuit is connected to the input end of the voltage divider circuit, the output end of the voltage divider circuit is respectively connected to the input ends of the plurality of mean current loop control circuits, and the mean current loop control circuit is connected to the peak current limiting protection circuit.

[0009] According to the above-mentioned solution of the utility model, the outer loop control circuit is a voltage loop control circuit or a power loop control circuit.

[0010] According to the utility model of the above scheme, the voltage loop control circuit includes a first integrated operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first capacitor, the first end of the first resistor is connected to an external auxiliary voltage signal, the second end of the first resistor, the first end of the second resistor and the reverse input end of the first integrated operational amplifier are interconnected, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor, the second end of the fifth resistor and the input end of the voltage divider circuit are interconnected, the first end of the fourth resistor is connected to an external reference voltage signal, the second end of the fourth resistor is connected to the non-inverting input end of the first integrated operational amplifier, and the output end of the first integrated operational amplifier is connected to the first end of the fifth resistor.

[0011] According to the above scheme of the utility model, the voltage loop control circuit also includes a second capacitor, a first end of the second capacitor is interconnected with the second end of the second resistor and the first end of the third resistor, and a second end of the second capacitor is interconnected with the second end of the first capacitor, the fifth resistor and the input end of the voltage divider circuit.

[0012] According to the above scheme of the utility model, the mean current loop control circuit includes a second integrated operational amplifier, a ninth resistor, a tenth resistor and an eleventh resistor, the first end of the ninth resistor is connected to the output end of the voltage divider circuit, the second end of the ninth resistor is connected to the inverting input end of the second integrated operational amplifier, the first end of the eleventh resistor is connected to the ground wire, the second end of the eleventh resistor is connected to the non-inverting input end of the second integrated operational amplifier, the output end of the second integrated operational amplifier is connected to the first end of the tenth resistor, and the second end of the tenth resistor is connected to an external load.

[0013] According to the above scheme of the utility model, the mean current loop control circuit also includes a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor. The first end of the sixth resistor is connected to an external auxiliary current signal, the second end of the sixth resistor, the second end of the ninth resistor, the first end of the seventh resistor and the inverting input end of the second integrated operational amplifier are interconnected, the second end of the seventh resistor, the first end of the eighth resistor and the first end of the third capacitor are interconnected, the second end of the eighth resistor is connected to the first end of the fourth capacitor, and the second end of the third capacitor, the second end of the fourth capacitor, the second end of the tenth resistor and the external load are interconnected.

[0014] According to the above-mentioned solution of the utility model, the voltage-dividing circuit includes a plurality of voltage-dividing resistors connected in series.

[0015] According to the utility model of the above scheme, the voltage divider circuit includes input and output resistors and a common-mode amplifier circuit, and the input and output resistors are connected to the common-mode amplifier circuit.

[0016] The utility model according to the above scheme has the beneficial effect that the utility model adopts dual-loop control of voltage loop and current loop, the output of the outer loop control circuit is acted on by the voltage divider circuit as the instruction of the mean current loop control circuit, and the current instruction obtained by each phase is the same. The mean current loop control circuit adopts the mean control method to ensure that the actual current of each phase will be close to the average value of the instruction current, and the current difference between phases is small. Combined with the respective peak current protection, it can ensure the current sharing of the control circuit while ensuring the safe operation of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a circuit principle block diagram of the utility model;

[0018] Figure 2 It is a schematic diagram of the structure of the voltage loop control circuit of the utility model;

[0019] Figure 3 It is a structural schematic diagram of the mean current loop control circuit of the utility model. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. Terms such as "setting" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "bottom", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and cannot be understood as limitations on the present technical solution.

[0022] It should be noted that in a multi-phase interleaved switching power supply, the current of each phase needs to be maintained at a relatively balanced level. However, it is difficult to maintain a balanced current in each phase of an existing multi-phase interleaved switching power supply. If the current of one phase is too large and the current of other phases is too small, the switch tube of the phase with large current will heat up seriously or even be damaged, thereby affecting the reliability and stability of the entire power supply system.

[0023] The embodiments of this patent take three-phase interleaving as an example, but are not limited to three-phase interleaving, and other interleaving numbers are also applicable.

[0024] like Figure 1-Figure 3 As shown, in order to achieve balanced current distribution in a multi-phase interleaved switching power supply, the present embodiment provides a current balancing circuit for a multi-phase interleaved switching power supply, which adopts dual-loop control of a voltage loop and a current loop. The output of the outer loop control circuit is acted on by a voltage divider circuit as an instruction of a mean current loop control circuit. The current instruction obtained by each phase is the same. The mean current loop control circuit adopts a mean control method to ensure that the actual current of each phase is close to the average value of the instruction current, and the current difference between phases is extremely small. Combined with their respective peak current protections, it can ensure the current balancing of the control circuit while also ensuring the safe operation of the circuit.

[0025] Specifically, the current equalizing circuit of the multi-phase interleaved switching power supply includes an outer loop control circuit, a voltage divider circuit, multiple mean current loop control circuits and multiple peak current limiting protection circuits. The output end of the outer loop control circuit is connected to the input end of the voltage divider circuit, and the output end of the voltage divider circuit is respectively connected to the input ends of the multiple mean current loop control circuits. The mean current loop control circuit is connected to the peak current limiting protection circuit.

[0026] A mean current loop control circuit controls each out-of-phase pulse individually. Except for the out-of-phase relationship of the carrier, there is no other relationship between the loops and they are independent of each other.

[0027] In general, dual-loop control is still used as the overall control method, which is the voltage loop (or power loop) and the current loop control method. The outer loop voltage loop control circuit (or power loop control circuit): that is, the control target, for example, the power supply needs to operate at constant voltage or constant power; the outer loop ensures the realization of the control target, and the output is the command current, which serves as the control input of the current loop. The inner loop is the current loop: the control current command of the outer loop is quickly converted into an actual current control pulse.

[0028] The voltage loop (power loop or other current instructions) is the control target. Regardless of whether the control target is output voltage, output power, or current, the output of the loop passes through a voltage divider circuit and serves as an instruction for the current loop control circuit. One-third voltage division is 3-phase staggered control. If it is N-phase staggered control, it is one-N voltage division.

[0029] In one embodiment, the voltage loop control circuit is mainly used to stabilize and adjust the voltage in the circuit to ensure that the key parts of the circuit can operate at a constant voltage. The circuit compares the external auxiliary voltage signal with the reference voltage signal and adjusts the output voltage through a feedback mechanism to achieve the desired stable voltage value.

[0030] Specifically, the voltage loop control circuit includes a first integrated operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first capacitor, the first end of the first resistor is connected to an external auxiliary voltage signal, the second end of the first resistor, the first end of the second resistor and the reverse input terminal of the first integrated operational amplifier are interconnected, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor, the second end of the fifth resistor and the input terminal of the voltage divider circuit are interconnected, the first end of the fourth resistor is connected to an external reference voltage signal, the second end of the fourth resistor is connected to the non-inverting input terminal of the first integrated operational amplifier, and the output terminal of the first integrated operational amplifier is connected to the first end of the fifth resistor.

[0031] The voltage loop control circuit also includes a second capacitor, a first end of the second capacitor is interconnected with the second end of the second resistor and the first end of the third resistor, and a second end of the second capacitor is interconnected with the second end of the first capacitor, the fifth resistor and the input end of the voltage divider circuit.

[0032] The first integrated operational amplifier compares the auxiliary voltage signal with the reference voltage signal and amplifies the difference between the two. If the auxiliary voltage signal is higher than the reference voltage signal, the operational amplifier will output a negative voltage; otherwise, it will output a positive voltage.

[0033] The first capacitor and the second capacitor play a filtering role in the circuit, which can eliminate high-frequency noise in the circuit and improve the stability of the output voltage.

[0034] In one embodiment, the current command obtained by each phase is exactly the same, and the gain of the current loop is very high. After closed-loop control, the actual current of each phase will be very close to the average value of the command current.

[0035] Specifically, the mean current loop control circuit includes a second integrated operational amplifier, a ninth resistor, a tenth resistor and an eleventh resistor, the first end of the ninth resistor is connected to the output end of the voltage divider circuit, the second end of the ninth resistor is connected to the inverting input end of the second integrated operational amplifier, the first end of the eleventh resistor is connected to the ground wire, the second end of the eleventh resistor is connected to the non-inverting input end of the second integrated operational amplifier, the output end of the second integrated operational amplifier is connected to the first end of the tenth resistor, and the second end of the tenth resistor is connected to an external load.

[0036] The mean current loop control circuit also includes a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor. The first end of the sixth resistor is connected to an external auxiliary current signal. The second end of the sixth resistor, the second end of the ninth resistor, the first end of the seventh resistor and the inverting input end of the second integrated operational amplifier are interconnected. The second end of the seventh resistor, the first end of the eighth resistor and the first end of the third capacitor are interconnected. The second end of the eighth resistor is connected to the first end of the fourth capacitor. The second end of the third capacitor, the second end of the fourth capacitor, the second end of the tenth resistor and the external load are interconnected.

[0037] In one embodiment, the voltage divider circuit includes a plurality of voltage divider resistors connected in series. The output of the outer loop control circuit is acted upon by the voltage divider resistors to ensure that the current command obtained by each phase is the same. The resistance values ​​of the voltage divider resistors are the same so as to divide the output of the input outer loop control circuit into several identical voltage values.

[0038] In one embodiment, the voltage divider circuit includes input and output resistors and a common-phase amplifier circuit, and the input and output resistors are connected to the common-phase amplifier circuit. The output of the outer loop control circuit passes through the output resistor and the common-phase amplifier circuit to ensure that the current command obtained by each phase is the same.

[0039] Specifically, the input resistor is connected to the output end of the outer loop control circuit for receiving the current command signal, while the output resistor is connected to the input end of the in-phase amplifier circuit for distributing the current command signal to each phase.

[0040] The outer loop control circuit outputs a voltage signal representing the current command. This voltage signal is first divided by the output resistor and then input into the common-mode amplifier circuit. The common-mode amplifier circuit adjusts the amplitude and phase of its output signal according to the amplitude and phase of the input signal to ensure that each phase receives the same current command.

[0041] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

[0042] The above is an exemplary description of the utility model patent in conjunction with the accompanying drawings. It is obvious that the implementation of the utility model patent is not limited to the above-mentioned method. As long as various improvements are made by adopting the method concept and technical solution of the utility model patent, or the concept and technical solution of the utility model patent are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A current sharing circuit for a multi-phase interleaved switching power supply, characterized in that: It includes an outer loop control circuit, a voltage divider circuit, multiple mean current loop control circuits and multiple peak current limiting protection circuits. The output end of the outer loop control circuit is connected to the input end of the voltage divider circuit, the output end of the voltage divider circuit is respectively connected to the input ends of the multiple mean current loop control circuits, and the mean current loop control circuit is connected to the peak current limiting protection circuit.

2. A current sharing circuit for a multi-phase interleaved switching power supply according to claim 1, characterized in that: The outer loop control circuit is a voltage loop control circuit or a power loop control circuit.

3. The current sharing circuit of a multi-phase interleaved switching power supply according to claim 2, characterized in that: The voltage loop control circuit includes a first integrated operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a first capacitor, the first end of the first resistor is connected to an external auxiliary voltage signal, the second end of the first resistor, the first end of the second resistor and the reverse input terminal of the first integrated operational amplifier are interconnected, the second end of the second resistor is connected to the first end of the third resistor, the second end of the third resistor is connected to the first end of the first capacitor, the second end of the first capacitor, the second end of the fifth resistor and the input terminal of the voltage divider circuit are interconnected, the first end of the fourth resistor is connected to an external reference voltage signal, the second end of the fourth resistor is connected to the non-inverting input terminal of the first integrated operational amplifier, and the output terminal of the first integrated operational amplifier is connected to the first end of the fifth resistor.

4. The current sharing circuit of a multi-phase interleaved switching power supply according to claim 3, characterized in that: The voltage loop control circuit also includes a second capacitor, a first end of the second capacitor is interconnected with the second end of the second resistor and the first end of the third resistor, and a second end of the second capacitor is interconnected with the second end of the first capacitor, the fifth resistor and the input end of the voltage divider circuit.

5. A current sharing circuit for a multi-phase interleaved switching power supply according to any one of claims 1 to 4, characterized in that: The mean current loop control circuit includes a second integrated operational amplifier, a ninth resistor, a tenth resistor and an eleventh resistor, wherein the first end of the ninth resistor is connected to the output end of the voltage divider circuit, the second end of the ninth resistor is connected to the inverting input end of the second integrated operational amplifier, the first end of the eleventh resistor is connected to the ground wire, the second end of the eleventh resistor is connected to the non-inverting input end of the second integrated operational amplifier, the output end of the second integrated operational amplifier is connected to the first end of the tenth resistor, and the second end of the tenth resistor is connected to an external load.

6. The current sharing circuit of a multi-phase interleaved switching power supply according to claim 5, characterized in that: The mean current loop control circuit also includes a sixth resistor, a seventh resistor, an eighth resistor, a third capacitor and a fourth capacitor. The first end of the sixth resistor is connected to an external auxiliary current signal, the second end of the sixth resistor, the second end of the ninth resistor, the first end of the seventh resistor and the inverting input end of the second integrated operational amplifier are interconnected, the second end of the seventh resistor, the first end of the eighth resistor and the first end of the third capacitor are interconnected, the second end of the eighth resistor is connected to the first end of the fourth capacitor, and the second end of the third capacitor, the second end of the fourth capacitor, the second end of the tenth resistor and the external load are interconnected.

7. A current sharing circuit for a multi-phase interleaved switching power supply according to claim 1, 2, 3, 4 or 6, characterized in that: The voltage dividing circuit includes a plurality of voltage dividing resistors connected in series.

8. A current sharing circuit for a multi-phase interleaved switching power supply according to claim 1, 2, 3, 4 or 6, characterized in that: The voltage divider circuit includes input and output resistors and a common-mode amplifier circuit, and the input and output resistors are connected to the common-mode amplifier circuit.

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