A method to improve the light-load efficiency of synchronous rectifier chips

Abstract

This invention relates to a method for improving the light-load efficiency of a synchronous rectifier chip. The method involves monitoring the voltage V between the output terminal K and the input terminal A of the synchronous rectifier chip. KA The V KA This reflects the change in load current; when the V KA When the voltage drops to the first preset voltage, based on V KA = -Is×Rdson is used to dynamically pre-adjust the Vgs drive voltage to counteract the Vgs voltage drop caused by the decrease in load current Is. KA The change extends the turn-on time of the synchronous rectifier chip; Rdson is the on-resistance of the MOSFET inside the synchronous rectifier chip; the dynamic pre-adjustment processing of the Vgs drive voltage includes: controlling the reduction of the Vgs drive voltage, utilizing the characteristic that Rdson increases as Vgs decreases in the MOSFET, and maintaining Vgs. KA The voltage remains constant.

Description

Technical Field

[0001] This invention relates to the field of electronic power technology, and in particular to a method for improving the light-load efficiency of synchronous rectifier chips. Background Technology

[0002] A power converter is a device used to convert a specific voltage and current from one power source to another. Energy losses occur during power conversion, primarily including conduction losses and switching losses. Conduction losses refer to the power loss generated during the conduction of the power converter's switching transistors, while switching losses refer to the power loss generated during the switching process.

[0003] Traditional power converters use diodes as rectifiers. Under light load conditions, the load current is small, and the conduction time of traditional diodes is long, resulting in high conduction losses. This leads to decreased efficiency and increased energy consumption in the power converter.

[0004] Synchronous rectifier chips solve this problem. Synchronous rectifier chips use metal-oxide-semiconductor field-effect transistors (MOSFETs) as the rectifier element. MOSFETs have low on-resistance and fast switching speed, which can effectively reduce conduction losses and switching losses.

[0005] Therefore, synchronous rectifier chips can improve the efficiency of power converters under light load conditions. By reducing conduction and switching losses, synchronous rectifier chips can reduce energy consumption and improve the overall efficiency of power converters. This is of great significance for electronic devices that need to operate for extended periods, such as mobile devices and wireless sensor networks. Improving the efficiency of power converters can extend battery life, reduce energy consumption, and enhance device operating time and performance.

[0006] Currently available synchronous rectification chips employ various technical solutions to improve efficiency under light loads, such as:

[0007] Synchronous rectification chips synchronize with the switching of main power switches (such as DC-DC converters) by controlling the turn-on and turn-off timing of MOSFETs to minimize turn-on and switching losses.

[0008] Low-impedance MOSFETs are used in synchronous rectifier chips. These MOSFETs have low on-resistance, which can reduce conduction losses.

[0009] By employing efficient drive circuitry and technology, the MOSFET can switch states rapidly, reducing energy loss during the switching process;

[0010] Each of the above methods has its advantages, but none of them can be adjusted in real time according to the load conditions, so their effect on improving the efficiency of synchronous rectifier chips under light load is limited. Summary of the Invention

[0011] The purpose of this invention is to provide a method for improving the light-load efficiency of synchronous rectifier chips by dynamically adjusting the Vgs drive voltage to maintain V KA Voltage stability, and maximum resistance to load current variations on V KA The influence of V. This can avoid the impact of V. KA Voltage fluctuations improve the light-load efficiency of synchronous rectifier chips and optimize the performance of power converters.

[0012] Therefore, embodiments of the present invention provide a method for improving the light-load efficiency of synchronous rectification chips, characterized in that the method includes:

[0013] Monitor the voltage V between the output terminal K and the input terminal A of the synchronous rectifier chip. KA The V KA This reflects the changes in load current;

[0014] When the V KA When the voltage drops to the first preset voltage, based on V KA = -Is×Rdson is used to dynamically pre-adjust the Vgs drive voltage to counteract the Vgs voltage drop caused by the decrease in load current Is. KA The change extends the turn-on time of the synchronous rectifier chip; Rdson is the on-resistance of the metal-oxide-semiconductor field-effect transistor (MOSFET) inside the synchronous rectifier chip;

[0015] The dynamic pre-adjustment process for the Vgs drive voltage includes: controlling the reduction of the Vgs drive voltage, and utilizing the characteristic that Rdson in the MOSFET increases as Vgs decreases to maintain Vgs. KA The voltage remains constant.

[0016] Preferably, the first preset voltage is -40mV.

[0017] Preferably, the dynamic pre-adjustment of the Vgs drive voltage is used to avoid the equivalent series inductance ESL and Vgs caused by changes in load current. KA Ripple causes V KA Voltage oscillations cause the synchronous rectifier chip to turn off prematurely under light load.

[0018] Preferably, during the dynamic pre-adjustment process of the Vgs driving voltage, the load current Is and V are continuously monitored in real time. KA The Vgs drive voltage is dynamically adjusted in real time according to the changes in voltage to optimize the operating parameters of the synchronous rectifier chip.

[0019] Preferably, the dynamic pre-adjustment processing of the Vgs driving voltage specifically includes:

[0020] Set the initial Vgs drive voltage;

[0021] Monitor the load current Is using a current sensor or a current sampling resistor;

[0022] According to V KA = -Is×Rdson to calculate the corresponding V KA Voltage, and compare it with a preset target voltage; if V KA A voltage higher than the target voltage indicates a large load current Is. Adjusting and reducing the Vgs drive voltage decreases the Rdson value to stabilize Vgs. KA Voltage; if V KA The voltage is lower than the target voltage, indicating that the load current Is is small. Adjust and increase the drive voltage Vgs to improve the Rdson value, so that V... KA The voltage remains stable.

[0023] The method for improving the light-load efficiency of synchronous rectifier chips provided in this invention dynamically adjusts the Vgs driving voltage to maintain V KA Voltage stability, and maximum resistance to load current variations on V KA The influence of V. This can avoid the impact of V. KA Voltage fluctuations improve the light-load efficiency of synchronous rectifier chips and optimize the performance of power converters. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating a method for improving the light-load efficiency of a synchronous rectifier chip, as provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] This invention provides a method for improving the light-load efficiency of synchronous rectification chips, such as... Figure 1 As shown, it includes:

[0027] Step 110: Monitor the voltage V between the output terminal K and the input terminal A of the synchronous rectifier chip. KA V KA It reflects the changes in load current.

[0028] Step 120, when V KA When the voltage drops to the first preset voltage, based on V KA = -Is×Rdson is used to dynamically pre-adjust the Vgs drive voltage to counteract the Vgs voltage drop caused by the decrease in load current Is. KA The change extends the turn-on time of the synchronous rectifier chip;

[0029] Rdson is the on-resistance of the MOSFET inside the synchronous rectifier chip.

[0030] In this example, the first preset voltage is -40mV. The purpose of this setting is to ensure that the voltage is within the range of V... KA The dynamic Vgs adjustment function is activated when the voltage drops to -40mV. This is an optional setting, depending on application requirements and design considerations.

[0031] This invention takes into account operational stability: in the power converter, V KA The voltage is an important reference voltage used to control the switching operation of the synchronous rectifier chip. By setting the preset voltage to -40mV, it can be ensured that V... KA The voltage is always kept at a low level to avoid excessive energy loss.

[0032] This invention also considers response speed: by setting the preset voltage to a lower value, such as -40mV, the dynamic adjustment of the Vgs drive voltage can be initiated more quickly when the load current drops to a certain level. This can accelerate the response speed to load changes and provide better efficiency and stability.

[0033] It is important to note that the preset voltage should be selected to match the design requirements and operating conditions of the specific application. In practical design, those skilled in the art need to perform system-level analysis and evaluation to determine the most suitable preset voltage value to meet performance, efficiency, and stability requirements.

[0034] The dynamic pre-adjustment processing of the Vgs driving voltage in this invention includes: controlling the reduction of the Vgs driving voltage, and utilizing the characteristic that Rdson in the MOSFET increases as Vgs decreases to maintain V KA The voltage remains constant.

[0035] The specific process of a Vgs drive voltage dynamic pre-adjustment process may include:

[0036] Step 121: Set the initial Vgs driving voltage;

[0037] Step 122: Monitor the load current Is using a current sensor or a current sampling resistor;

[0038] Step 123, according to V KA = -Is×Rdson to calculate the corresponding V KA Voltage, and compare it with a preset target voltage; if V KA A voltage higher than the target voltage indicates a large load current Is. Adjusting and reducing the Vgs drive voltage decreases the Rdson value to stabilize Vgs. KA Voltage; if V KAThe voltage is lower than the target voltage, indicating that the load current Is is small. Adjust and increase the drive voltage Vgs to improve the Rdson value, so that V... KA The voltage remains stable.

[0039] Rdson represents the on-resistance of a MOSFET, also known as the turn-on resistance. Rdson refers to the resistance between the source and drain of the MOSFET when it is turned on. It describes the conductivity characteristics of a MOSFET when it is conducting. The value of Rdson affects the conduction loss of the MOSFET.

[0040] During the dynamic pre-adjustment process of the Vgs drive voltage, the load current Is and V are continuously monitored in real time. KA The Vgs drive voltage is dynamically adjusted in real time according to the changes in voltage to optimize the operating parameters of the synchronous rectifier chip.

[0041] In power converters, synchronous rectifier chips are used to control the direction of current flow to achieve efficient energy conversion. When the synchronous rectifier chip is turned on, current can flow from the power source to the load, reducing energy loss. Therefore, a longer on-time can minimize conduction losses and improve the efficiency of the power converter.

[0042] Dynamic pre-adjustment of the Vgs drive voltage is used to avoid the effects of equivalent series inductance (ESL) and Vgs due to load current variations. KA Ripple causes V KA Voltage oscillations cause the synchronous rectifier chip to turn off prematurely under light load.

[0043] ESL is the equivalent series inductance in a power converter, typically caused by circuit layout and component routing. When the load current changes, ESL can cause V... KA Voltage fluctuations and ripples can negatively impact the operation of synchronous rectifier chips. If V KA When the voltage oscillates to near 0V, the synchronous rectifier chip may turn off prematurely under light load, thus reducing its efficiency under light load.

[0044] This invention aims to optimize the conduction time of a synchronous rectifier chip by dynamically adjusting the Vgs driving voltage under light load conditions, thereby maximizing the extension of the chip's on-state. By dynamically adjusting the Vgs driving voltage, the conduction time of the synchronous rectifier chip is maintained. KA Voltage stability, and maximum resistance to load current variations on V KA The influence of V. This can avoid the impact of V. KA Voltage fluctuations improve the light-load efficiency of synchronous rectifier chips and optimize the performance of power converters to improve energy conversion efficiency.

[0045] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0046] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented in hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0047] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the light-load efficiency of a synchronous rectifier chip, characterized in that, The method includes: Monitor the voltage V between the output terminal K and the input terminal A of the synchronous rectifier chip. KA The V KA This reflects the changes in load current; When the V KA When the voltage drops to the first preset voltage, based on V KA = -Is × Rdson and the preset target voltage are used to dynamically pre-adjust the Vgs drive voltage to counteract the Vgs caused by the decrease in load current Is. KA The change extends the turn-on time of the synchronous rectifier chip; Rdson is the on-resistance of the metal-oxide-semiconductor field-effect transistor (MOSFET) inside the synchronous rectifier chip; The dynamic pre-adjustment processing of the Vgs driving voltage specifically includes: Set the initial Vgs drive voltage; Monitor the load current Is using a current sensor or a current sampling resistor; According to V KA = -Is × Rdson to calculate the corresponding V KA Voltage, and compare it with a preset target voltage; if V KA A voltage higher than the target voltage indicates a large load current Is. Adjusting and reducing the Vgs drive voltage decreases the Rdson value to stabilize Vgs. KA Voltage; if V KA The voltage is lower than the target voltage, indicating that the load current Is is small. Adjust and increase the drive voltage Vgs to improve the Rdson value, so that V... KA The voltage remains stable; During the dynamic pre-adjustment process of the Vgs driving voltage, the load current Is and V are continuously monitored in real time. KA The Vgs drive voltage is dynamically adjusted in real time according to the changes in voltage to optimize the operating parameters of the synchronous rectifier chip.

2. The method according to claim 1, characterized in that, The first preset voltage is -40mV.

3. The method according to claim 1, characterized in that, The dynamic pre-adjustment of the Vgs driving voltage is used to avoid the equivalent series inductance ESL and Vgs caused by changes in load current. KA Ripple causes V KA Voltage oscillations cause the synchronous rectifier chip to turn off prematurely under light load.

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