Efficient step-down output system and method

Abstract

The invention discloses an efficient step-down output system and method, and the system comprises a feedback loop module and a driving module, the feedback loop module comprises a voltage loop unit and a plurality of current loop units, the voltage loop unit is used for controlling the output of a stable voltage, and the current loop units are used for controlling the current-sharing work of a plurality of BUCK driving units; comprising multiple BUCK driving units, each BUCK driving unit comprises synchronous voltage reduction controllers, the synchronous voltage reduction controllers are connected with current loops in a one-to-one correspondence mode, the current loop units are used for controlling the driving duty ratios of the corresponding synchronous voltage reduction controllers, the synchronous voltage reduction controllers are connected with synchronous output signal frequencies, and staggered parallel output of the multiple BUCK driving units is achieved. The purposes of small single-path output current, less circuit loss, improved efficiency and effective reduction of device temperature are achieved.

Description

Technical Field

[0001] The present invention relates to the field of synchronous buck technology, and more specifically, to a high-efficiency buck output system and method. Background Art

[0002] With the rapid development of modern electronic technology, the performance improvement of switching power supplies, as an indispensable energy conversion component in electronic equipment, is directly related to the stability, reliability and energy efficiency of the entire system. Especially in the technical fields of communications, data centers, automotive electronics, industrial automation, etc., the requirements for switching power supplies are becoming increasingly stringent. Not only are they required to have high efficiency and high power density, but they are also required to work stably within a wide input voltage range while maintaining good thermal management performance to adapt to complex and changing working environments.

[0003] MK9218 is a synchronous step-down DC / DC controller that can operate in a wide input voltage range of 6V to 100V. However, when MK9218 is applied to a switching buck power supply with low voltage, high current output and high power density, it encounters problems of low efficiency and excessive device temperature. Summary of the invention

[0004] In order to overcome the problems of low efficiency and excessive device temperature when the existing MK9218 is applied to a switching BUCK step-down power supply with low voltage, high current output and high power density, the present invention provides a high-efficiency step-down output system and method.

[0005] The technical solution of the present invention is as follows:

[0006] A high-efficiency step-down output system, comprising:

[0007] A feedback loop module, the feedback loop module comprising a voltage loop unit and a plurality of current loop units, the voltage loop unit being used to control the output stable voltage, and the current loop unit being used to control the current sharing work of multiple BUCK drive units;

[0008] The driving module includes a plurality of BUCK driving units, wherein the BUCK driving units include synchronous buck controllers, each synchronous buck controller is connected to the current loop in a one-to-one correspondence, and the current loop unit is used to control the driving duty cycle of the corresponding synchronous buck controller, and each synchronous buck controller is connected to a synchronous output signal frequency.

[0009] According to the above scheme of the present invention, the synchronous buck controller includes a first synchronous buck controller and a second synchronous buck controller, the first synchronous buck controller is connected to the VCC terminal, the first synchronous buck controller is connected to the second synchronous buck controller, and outputs a square wave signal to the second synchronous buck controller.

[0010] According to the above scheme of the present invention, the first synchronous buck controller outputs a first signal frequency, the square wave signal is delayed by 180° from the first signal frequency, and the second synchronous buck controller outputs a second signal frequency, the first signal frequency is the same as the second signal frequency.

[0011] According to the above-mentioned solution of the present invention, the first pin of the synchronous buck controller is an enable pin, which is used to control the on and off of the synchronous buck controller.

[0012] According to the above scheme of the present invention, the second pin of the synchronous buck controller is connected to the second resistor, and the second resistor is used to set the switching frequency driven by the synchronous buck controller; the fourth pin of the synchronous buck controller is connected to the current loop unit, which is used to control the driving duty cycle of the synchronous buck controller; the fifth pin and the sixth pin of the synchronous buck controller are both grounded.

[0013] According to the above scheme of the present invention, the seventh pin of the first synchronous buck controller is connected to the eighth pin of the second synchronous buck controller, the eighth pin of the first synchronous buck controller is connected to the VCC terminal, and the seventh pin of the second synchronous buck controller is an empty pin.

[0014] According to the above scheme of the present invention, the feedback loop module also includes an output voltage sampling circuit, which includes a plurality of voltage-dividing resistors connected in series and a shunt resistor connected in parallel with the voltage-dividing resistors, and both the voltage-dividing resistors and the shunt resistors are connected to the voltage loop unit.

[0015] According to the above scheme of the present invention, the voltage loop unit includes a first operational amplifier, the input end of the first operational amplifier is connected to the output voltage sampling circuit, and is used to receive the sampling signal output by the output voltage circuit. The input end of the first operational amplifier is also connected to the reference voltage.

[0016] According to the present invention of the above scheme, the current loop unit includes a second operational amplifier, the output end of the first operational amplifier is connected to the input end of the second operational amplifier, the input end of the second operational amplifier is also connected to the output current sampling amplification signal, and the output end of the second operational amplifier is also connected to the synchronous buck controller.

[0017] A high-efficiency step-down output method, applicable to any of the high-efficiency step-down output systems described above, comprises the following steps:

[0018] S1, output voltage sampling circuit samples output voltage signal;

[0019] S2, input the output voltage signal collected in S1 to the voltage loop unit, and input the reference voltage to the voltage loop unit at the same time, and the voltage loop unit outputs the sampled and amplified signal;

[0020] S3, input the sampling and amplifying signals in S2 to each current loop unit respectively, and input the current sampling and amplifying signals output by the corresponding BUCK driving unit to each current loop unit at the same time, and each current loop unit outputs a control signal to the corresponding BUCK driving unit respectively to control the driving duty cycle of each BUCK driving unit;

[0021] S4. Each BUCK driving unit interacts with each other to preset a phase difference signal, and each BUCK driving unit drives the corresponding BUCK circuit switch tube in turn, and each BUCK circuit feeds back a current sampling and amplification signal to the corresponding current loop unit.

[0022] The beneficial effect of the present invention according to the above scheme is that the synchronous buck controller of the present invention receives instructions from the current loop unit and accurately controls its driving duty cycle. The synchronous buck controller synchronously outputs the same signal frequency, and the outputs of each synchronous buck controller are staggered, that is, the switching actions of different BUCK drive units are staggered in time, avoiding current shocks and voltage fluctuations caused by simultaneous switching, and reducing electromagnetic interference and noise. The staggered parallel working mode not only improves the dynamic response capability of the system, but also makes the total output current smoother, which is conducive to the stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a system architecture diagram of the present invention;

[0024] Figure 2 is a circuit diagram of a feedback circuit module of the present invention;

[0025] Figure 3 is a circuit diagram of a BUCK driving unit of the present invention;

[0026] Figure 4 A circuit diagram of a BUCK circuit of the present invention;

[0027] Figure 5 It is a diagram of the method steps of the present invention. DETAILED DESCRIPTION

[0028] 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.

[0029] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention 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 may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. Terms such as "disposed" 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.

[0030] It should be noted that with the rapid development of modern electronic technology, the performance improvement of switching power supplies, as an indispensable energy conversion component in electronic equipment, is directly related to the stability, reliability and energy efficiency of the entire system. Especially in the technical fields of communications, data centers, automotive electronics, industrial automation, etc., the requirements for switching power supplies are becoming increasingly stringent. Not only are they required to have high efficiency and high power density, but they are also required to work stably within a wide input voltage range, while maintaining good thermal management performance to adapt to complex and changing working environments.

[0031] MK9218 is a synchronous step-down DC / DC controller that can operate in a wide input voltage range of 6V to 100V. However, when MK9218 is applied to a switching buck power supply with low voltage, high current output and high power density, it encounters problems of low efficiency and excessive device temperature.

[0032] like Figure 1-Figure 4 As shown, this embodiment provides a high-efficiency buck output system, which realizes the staggered parallel output of multiple BUCK drive units, so as to achieve the purpose of small single-channel output current, low circuit loss, improved efficiency, and effective reduction of device temperature.

[0033] Specifically, the high-efficiency buck output system includes a feedback loop module and a drive module. The feedback loop module includes a voltage loop unit and multiple current loop units. The voltage loop unit is used to control the output stable voltage, and the current loop unit is used to control the current sharing work of multiple BUCK drive units.

[0034] The drive module includes multiple BUCK drive units, each of which includes a synchronous buck controller. Each synchronous buck controller is connected to a current loop in a one-to-one correspondence. The current loop unit is used to control the driving duty cycle of the corresponding synchronous buck controller. Each synchronous buck controller is connected to a synchronous output signal frequency. Each synchronous buck controller staggers the output to drive the corresponding BUCK circuit switch tube.

[0035] The voltage loop unit can quickly adjust the control strategy to maintain a constant output voltage and meet the high voltage stability requirements of the load. The current loop unit works independently to jointly monitor and adjust the current output of each drive unit to ensure balanced distribution of multiple output currents.

[0036] The synchronous buck controller receives instructions from the current loop unit and accurately controls its driving duty cycle. The synchronous buck controller synchronously outputs the same signal frequency, and the outputs of each synchronous buck controller are staggered, that is, the switching actions of different BUCK drive units are staggered in time, avoiding current shocks and voltage fluctuations caused by simultaneous switching, and further reducing electromagnetic interference and noise. The staggered parallel working mode not only improves the dynamic response capability of the system, but also makes the total output current smoother, which is conducive to the stable operation of the system.

[0037] In one embodiment, the synchronous buck controller includes a first synchronous buck controller and a second synchronous buck controller, the first synchronous buck controller is connected to the VCC terminal, the first synchronous buck controller is connected to the second synchronous buck controller, and outputs a square wave signal to the second synchronous buck controller.

[0038] In this embodiment, the first synchronous buck controller outputs a first signal frequency, the first signal frequency controls the switch of the MOS tube in the first BUCK circuit, and the square wave signal is delayed by 180° from the first signal frequency. The second synchronous buck controller outputs a second signal frequency, the second signal frequency controls the switch of the MOS tube in the second BUCK circuit, and the first signal frequency is the same as the second signal frequency.

[0039] Specifically, the first synchronous buck controller is directly connected to the VCC terminal of the system, so that the first synchronous buck controller operates in FPWM mode, and the VCC terminal serves as the main energy input source for the entire voltage conversion process. The first synchronous buck controller processes the input voltage and also generates and outputs a first signal frequency, which is used to control the switching state of the MOS tube in the first BUCK circuit, thereby adjusting the output voltage. The first synchronous buck controller also generates a square wave signal with a phase delay of 180° with the first signal frequency. The square wave signal is then transmitted to the second synchronous buck controller, so that the second synchronous buck controller operates in FPWM mode.

[0040] The second synchronous buck controller receives a square wave signal from the first synchronous buck controller to ensure synchronization between the two synchronous buck controllers. Based on the received square wave signal, the second synchronous buck controller outputs a second signal frequency, which is used to control the switching state of the MOS tube in the second BUCK circuit. The second signal frequency is the same as the first signal frequency, and is output in an interleaved manner in time, that is, the phase difference is 180°. The first synchronous buck controller and the second synchronous buck controller respectively drive the switch of the MOS tube in the first BUCK circuit and the switch of the MOS tube in the second BUCK circuit, thereby realizing the interleaved parallel operation of the first BUCK circuit and the second BUCK circuit, jointly bearing the load current, effectively dispersing the heat load of a single circuit, and improving the efficiency and stability of the entire system. Interleaved parallel operation not only reduces the ripple of the output voltage, but also improves the dynamic response capability of the system, so that the system can adjust the output voltage faster when facing load changes and maintain the stability of the output voltage.

[0041] In one embodiment, the first pin of the synchronous buck controller is an enable pin, which is used to control the on and off of the synchronous buck controller. When the voltage of the first pin is greater than 1.2V, the synchronous buck controller starts to work.

[0042] The second pin of the synchronous buck controller is connected to a second resistor, and the second resistor is grounded. The second resistor is used to set the switching frequency driven by the synchronous buck controller. The switching frequency determines the ripple size and efficiency of the output voltage. By selecting a suitable resistor value, the switching frequency can be optimized to meet the needs of a specific application.

[0043] The fourth pin of the synchronous buck controller is connected to the current loop unit and is used to control the driving duty cycle of the synchronous buck controller;

[0044] The fifth pin and the sixth pin of the synchronous buck controller are both grounded to provide a stable reference potential to ensure the normal operation of the circuit.

[0045] The seventh pin of the first synchronous buck controller is connected to the eighth pin of the second synchronous buck controller to achieve synchronization or cascade operation between the two synchronous buck controllers. The eighth pin of the first synchronous buck controller is connected to the VCC terminal, and the seventh pin of the second synchronous buck controller is an empty pin.

[0046] It should be noted that the models of the first synchronous buck controller and the second synchronous buck controller are both MK9218.

[0047] In one embodiment, the feedback loop module further includes an output voltage sampling circuit, which includes a plurality of voltage dividing resistors connected in series and a shunt resistor connected in parallel with the voltage dividing resistors, and both the voltage dividing resistors and the shunt resistors are connected to the voltage loop unit.

[0048] In this embodiment, the voltage loop unit includes a first operational amplifier, the input end of the first operational amplifier is connected to the output voltage sampling circuit for receiving a sampling signal output by the output voltage circuit, and the input end of the first operational amplifier is also connected to a reference voltage.

[0049] The current loop unit includes a second operational amplifier, the output end of the first operational amplifier is connected to the input end of the second operational amplifier, the input end of the second operational amplifier is also connected to the output current sampling amplified signal, and the output end of the second operational amplifier is also connected to the synchronous buck controller.

[0050] The specific working principle is as follows: the feedback loop module includes a voltage loop based on U18-A and a current loop based on U20. The voltage loop is mainly used to control the voltage output voltage stability, and the current loop is mainly used to achieve the current sharing of the two BUCK circuits. R83, R79, R74, and R78 are output voltage sampling circuits. The output voltage signal collected by the output voltage sampling circuit is sent to the second pin of U18-A through R71. VREF is the reference voltage, which is transmitted to the third pin through R84. The signals of the second and third pins of U18-A are differentially amplified by the internal integrated circuit and then output the sampling and amplification signals through the first pin of U18-A. The sampling and amplification signals are transmitted to the third and fifth pins of U20 through R88. BUCK-IS1 is the output current sampling and amplification signal of the first BUCK circuit, which is transmitted to the sixth pin of U20 through R90. BUCK-IS2 is the output current sampling and amplification signal of the second BUCK circuit, which is transmitted to the second pin of U20 through R92. After differential amplification of the two signals of the fifth and sixth pins of U20 by the internal integrated circuit, a control signal is output through the seventh pin of U20, and the control signal pulls the level of COMP1 through R94; after differential amplification of the two signals of the second and third pins of U20 by the internal integrated circuit, a control signal is output through the first pin of U20, and the control signal pulls the level of COMP2 through R95. Because the signals of the third and fifth pins of U20 are the same, when BUCK-IS1 is larger than BUCK-IS2, after differential amplification of the integrated circuit of U20, COMP2 will be larger than COMP1, the current of the second BUCK circuit will increase, and the current of the first BUCK circuit will decrease. The same is true when BUCK-IS2 is larger than BUCK-IS1, so the two BUCK circuits can achieve current sharing.

[0051] In the BUCK circuit, the BUCK output current is sampled through a resistor and then amplified by an operational amplifier to obtain BUCK-IS.

[0052] like Figure 5 As shown, this embodiment provides a high-efficiency buck output method, which is applicable to a high-efficiency buck output system, and includes the following steps:

[0053] S1, output voltage sampling circuit samples output voltage signal;

[0054] S2, input the output voltage signal collected in S1 to the voltage loop unit, and input the reference voltage to the voltage loop unit at the same time, and the voltage loop unit outputs the sampled and amplified signal;

[0055] The voltage loop unit receives the actual output voltage signal from the output voltage sampling circuit and the preset reference voltage value. By comparing the two signals, the voltage loop unit calculates the error voltage and uses the adjustment algorithm to amplify and correct the error to generate a sampled amplified signal.

[0056] S3, input the sampling and amplifying signals in S2 to each current loop unit respectively, and input the current sampling and amplifying signals output by the corresponding BUCK driving unit to each current loop unit at the same time, and each current loop unit outputs a control signal to the corresponding BUCK driving unit respectively to control the driving duty cycle of each BUCK driving unit;

[0057] The current loop unit receives the sampled and amplified signal from the voltage loop unit (as a reference for current regulation) and the current sampled and amplified signal directly from the corresponding buck drive unit. By comparing these two signals, the current loop unit generates a current control signal, which dynamically adjusts the duty cycle of the buck drive unit, thereby controlling the current flowing through the buck circuit switch tube to achieve the established voltage and current output requirements.

[0058] S4. Each BUCK driving unit interacts with each other to preset a phase difference signal, and each BUCK driving unit drives the corresponding BUCK circuit switch tube in turn, and each BUCK circuit feeds back a current sampling and amplification signal to the corresponding current loop unit.

[0059] The high-efficiency buck output method of this embodiment effectively improves the efficiency, stability and response speed of the buck conversion system through precise voltage and current control strategies.

[0060] 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 appended claims of the present invention.

[0061] The above is an exemplary description of the present invention in conjunction with the accompanying drawings. It is obvious that the implementation of the present invention 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 present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A high-efficiency step-down output system, characterized in that: include: A feedback loop module, the feedback loop module comprising a voltage loop unit and a plurality of current loop units, the voltage loop unit being used to control the output stable voltage, and the current loop unit being used to control the current sharing work of multiple BUCK drive units; The driving module includes a plurality of BUCK driving units, wherein the BUCK driving units include synchronous buck controllers, each synchronous buck controller is connected to the current loop unit in a one-to-one correspondence, and the current loop unit is used to control the driving duty cycle of the corresponding synchronous buck controller, and each synchronous buck controller is connected to a synchronous output signal frequency.

2. The high-efficiency step-down output system according to claim 1, characterized in that: The synchronous buck controller includes a first synchronous buck controller and a second synchronous buck controller, the first synchronous buck controller is connected to the VCC terminal, the first synchronous buck controller is connected to the second synchronous buck controller, and outputs a square wave signal to the second synchronous buck controller.

3. The high-efficiency step-down output system according to claim 2, characterized in that: The first synchronous buck controller outputs a first signal frequency, the square wave signal is delayed by 180° from the first signal frequency, and the second synchronous buck controller outputs a second signal frequency, the first signal frequency is the same as the second signal frequency.

4. A high-efficiency step-down output system according to claim 2 or 3, characterized in that: The first pin of the synchronous buck controller is an enable pin, which is used to control the on and off of the synchronous buck controller.

5. The high-efficiency step-down output system according to claim 4, characterized in that: The second pin of the synchronous buck controller is connected to a second resistor, and the second resistor is used to set the switching frequency driven by the synchronous buck controller; the fourth pin of the synchronous buck controller is connected to the current loop unit, and is used to control the driving duty cycle of the synchronous buck controller; the fifth pin and the sixth pin of the synchronous buck controller are both grounded.

6. The high-efficiency step-down output system according to claim 4, characterized in that: The seventh pin of the first synchronous buck controller is connected to the eighth pin of the second synchronous buck controller, the eighth pin of the first synchronous buck controller is connected to the VCC terminal, and the seventh pin of the second synchronous buck controller is an empty pin.

7. A high-efficiency step-down output system according to claim 1, 2, 3, 5 or 6, characterized in that: The feedback loop module also includes an output voltage sampling circuit, which includes a plurality of voltage-dividing resistors connected in series and a shunt resistor connected in parallel with the voltage-dividing resistors, and both the voltage-dividing resistors and the shunt resistors are connected to the voltage loop unit.

8. The high-efficiency step-down output system according to claim 7, characterized in that: The voltage loop unit comprises a first operational amplifier, the input end of which is connected to the output voltage sampling circuit for receiving a sampling signal output by the output voltage circuit, and the input end of the first operational amplifier is also connected to a reference voltage.

9. The high-efficiency step-down output system according to claim 8, characterized in that: The current loop unit includes a second operational amplifier, the output end of the first operational amplifier is connected to the input end of the second operational amplifier, the input end of the second operational amplifier is also connected to the output current sampling amplified signal, and the output end of the second operational amplifier is also connected to the synchronous buck controller.

10. A high-efficiency step-down output method, characterized in that: The high-efficiency step-down output system applicable to any one of claims 1 to 9 comprises the following steps: S1, output voltage sampling circuit samples output voltage signal; S2, input the output voltage signal collected in S1 to the voltage loop unit, and input the reference voltage to the voltage loop unit at the same time, and the voltage loop unit outputs the sampled and amplified signal; S3, input the sampling and amplifying signals in S2 to each current loop unit respectively, and input the current sampling and amplifying signals output by the corresponding BUCK driving unit to each current loop unit at the same time, and each current loop unit outputs a control signal to the corresponding BUCK driving unit respectively to control the driving duty cycle of each BUCK driving unit; S4. Each BUCK driving unit interacts with each other to preset a phase difference signal, and each BUCK driving unit drives the corresponding BUCK circuit switch tube in turn, and each BUCK circuit feeds back a current sampling and amplification signal to the corresponding current loop unit.

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