革新高功率AI伺服器电源供应单元（PSUs）:交错式图腾柱PFC中混合TCM/CCM控制的优势

The rapid evolution of artificial intelligence (AI) has driven significant advancements in server power supply units (PSUs). With increasing power demands, efficiency requirements, and the need for modularity, the interleaved totem pole (TTP) power factor correction (PFC) topology has emerged as a leading solution. This article explores the advantages of hybrid triangular current mode (TCM) and continuous current mode (CCM) control strategies in interleaved TTP PFCs, highlighting their role in revolutionizing high-power AI server PSUs.

人工智能的快速变革不停驱动着伺服器电源供应单元（PSUs）的重要改动。随着功率需求、效率要求以及模块化必要性的增加，该交错式图腾柱（TTP）功率因数校正（PFC）拓扑作为一款前沿解决方案兴起。本文讨论了混合三角电流模式（TCM）和连续电流模式（CCM）控制策略在交错式TTP PFC中的优势，强调了其在革新高功率伺服器AI伺服器PSU中的重要性。

Background: Trends in AI Server PSUs

背景：AI服务器PSU趋势

The AI server market is experiencing unprecedented growth, which lead to increasing power demand with single PSUpower levels projected to rise to 5.5–8 kW by 2025. This increase is driven by the adoption of GPUs supporting 48 V outputs, which have become the industry standard. For instance, AI servers such as the ASUS ESC-N8-E11 and NVIDIA HGX H100 require power levels 3–10 times higher than traditional servers. To meet these demands, advanced control strategies, including hybrid TCM/CCM, GaN and SiC technologies, are essential for achieving high efficiency, increasedpower density, and reliability.

AI服务器市场正经历爆发式增长，推动单电源模块功率需求激增，预计2025年将跃升至5.5kW ~ 8kW。这一增长由支持48V输出的GPU普及所推动，该标准已成行业规范。例如华硕ESC-N8-E11及英伟达HGX H100等AI服务器，其功耗需求已达传统服务器的3至10倍。为满足需求，必须采用混合TCM/CCM模式、氮化镓/碳化硅技术等先进控制策略，方能实现高效能、高功率密度与卓越可靠性。

Hybrid TCM/CCM Control

混合TCM/CCM控制

Figure 1: Totem pole PFC architecture

图1：图腾柱PFC架构

Hybrid TCM/CCM control combines the strengths of both modes to optimize efficiency across varying load conditions. Key features include:

混合TCM/CCM控制涵括了两类模式的双重优势，基于多种负载工况优化效率。关键特征包括：

 · Optimized efficiency:

   · The hybrid strategy can switch between TCM and CCM based on load conditions, optimizing efficiency across a wide range of operating points.

   · TCM is more efficient at light loads due to reduced switching losses, while CCM is more efficient at higher loads due to lower conduction losses.

 · 能效更高：

   · 该混合策略可基于负载工况在TCM与CCM模式间动态切换，实现宽范围工作点的能效优化。

   · TCM模式在轻载工况下因开关损耗降低而能效更优，而CCM模式在重载时凭借导通损耗减少实现更高效率。

 · Reduced ripple current:

   · Interleaving two phases helps in significantly reducing the input and output current ripple.

   · The hybrid approach can further optimize ripple reduction by dynamically adjusting the operating mode.

 · 纹波电流更少：

   · 双阶段交错协助大幅减少输入及输出电流纹波。

   · 该混合方案可通过动态调整工作模式来进一步优化纹波减少。

 · Enhanced thermal management:

   · Distributing the load between two phases and switching between TCM and CCM can lead to better thermal performance and more balanced heat dissipation.

 · 热管理更强：

   · 双阶段负载分配及TCM与CCM模式转换可优化热性能并促使热耗散更加均衡。

 · Improved transient response:

   · The ability to switch between TCM and CCM allows the system to quickly adapt to changes in load, providing a better transient response.

 · 瞬态响应更佳:

   · TCM与CCM模式的切换功能会让系统更快适应负载变化，带来更快的瞬态响应。

 · Flexibility and reliability:

   · The hybrid control strategy offers flexibility in design and application, making it suitable for various operating conditions.

   · It can enhance the reliability of the PFC circuit by reducing stress on components and improving thermal management.

 · 灵活性与可靠性：

   · 该混合控制策略提供设计与应用的双重灵活性，广泛适配多变工况。

   · 通过降低元件应力与优化热管理，显著提升PFC电路可靠性。

Figure 2: Comparison of TCM/CCM in control strategy

图2：TCM/CCM控制策略对比

Implementation in Interleaved TTP PFC

交错式TTP PFC中的应用

The interleaved TTP PFC topology leverages hybrid TCM/CCM control to achieve superior performance. Key design parameters include:

 · Switching Frequency Range: 50–180 kHz

 · Input Voltage: 180–305 VAC

 · Target Efficiency: Peak efficiency of 99.2% and full-load efficiency of 98.6%

该交错式TTP拓扑采用混合TCM/CCM控制以达到优越性能。关键设计参数包括：

 · 开关频率范围： 50–180 kHz

 · 输入电压：180–305 VAC

 · 目标效率：峰值效率99.2%；全负载效率98.6%

Control Strategy and Key Features

控制策略及关键特点

The hybrid TCM/CCM control strategy is implemented using advanced components such as the STM32G474 microcontroller. ST Power and Energy Competence Center offers 5.5kW advantages of hybrid TCM/CCM control in interleaved TTP PFC Reference Designbased on STM32G4 Digital Controller to fit this high growth market.

该混合TCM/CCM控制策略通过采用STM32G74微控制器等高级组件来实现。意法半导体电源与能源创新技术中心研发了基于STM32G4全数字控制的5.5kW混合TCM/CCM交错式TTP PFC参考设计来满足这一高增长需求。

This 5.5kW advantages of hybrid TCM/CCM control in interleaved TTP PFC reference design introduces a complete ST’s digital power solution for high power interleaved TTP PFC applications based on the Mixed mode control methods topology. Reference design topology is mostly used for AI server power ORV3 and MCRPS Server power applications.

该基于STM32G4全数字控制的5.5kW混合TCM/CCM交错式TTP PFC参考设计基于混合模态控制拓扑，为高功率交错TTP PFC应用提供完整的意法半导体数字电源解决方案。此参考设计拓扑主要面向AI服务器电源（ORV3/MCRPS标准）场景。

This reference design achieves larger than 99.2% peak efficiency by utilizing ST’s 650V, 40mohmSiC MOSFET’s and 600V, 30mohm HV MOSFET’s which is TOLL package. It features fully digital control, with the STM32G474mixed-signal high performance microcontroller. Providing the control mode is operated in Interleaved Mixed Mode Totem Pole PFC control. Operating interleaved to reduce ripple current and reduce output capacitance value. When the load is below half load, the TCM is operated and ZVS is achieved, effectively improvingefficiency. When the load is higher than half load, it operates in CCM and effectively reduces the inductor current ripple, thereby reducing conduction loss.And at full load PF higher than 0.98, iTHD lower than 5%. We also have increasedSTPM32 (Metering solution) on our PFC stage. And verify that it is fully functional.

该参考设计采用意法半导体650V/40mΩ SiC MOSFET与600V/30mΩ高压MOSFET（TOLL封装），峰值效率突破99.2%，结合STM32G474混合信号高性能微控制器实现全数字化控制。方案采用交错式混合模式图腾柱PFC控制，通过交错运行降低纹波电流并缩减输出电容容值。半载以下负载启用TCM，实现ZVS，高效提升能效；半载以上切换至CCM，显著抑制电感电流纹波，降低导通损耗。满载工况下PF＞0.98，iTHD＜5%。我们更在PFC级集成STPM32计量方案，并验证其功能完备性。

With very competitive features:

 · Interleaved TTP PFC converter with Mixed mode control TCM/CCM topology

 · Input AC Voltage: 208 to 277VAC

 · Input AC Frequency: 47Hz to 63Hz

 · Output range: DC voltage 400 to 420 VDC

 · Maximum power: 5.5 kW

 · Peak efficiency>99.2%(Rated 230VAC)

 · High switching frequency operation (50kHz~180kHz)

 · Power Factor > 0.98 @ 100% load

 · iTHD < 5% @ 100% load

 · STPM32 (Metering solution)

具有极具竞争力的优势：

 · 交错TTP PFC 转换器带混合模式控制TCM/CCM拓扑

 · 输入AC电压：208~277 VAC

 · 输入AC频率： 47Hz ~ 63Hz

 · 输出范围：DC 电压400 ~ 420 V

 · 最大功率： 5.5 kW

 · 峰值效率>99.2%(额定230VAC)

 · 高开关频率工作 (50kHz~180kHz)

 · 功率因数> 0.98 @ 100%负载

 · iTHD < 5% @ 100%负载

 · STPM32 (计量方案)

Platform overview

平台概览

Figure 3: System Architecture of mixed mode control in interleaved TTP PFC

图3：交错式TTP PFC混合模式控制系统架构

Digital control provides a mixed mode control of both TCM and CCM for light-load to full-load conditions, the maximum efficiency 208Vac~277Vac and the load is from 10% to 100%, the efficiency can reach 97.88% at 10% load and over 98.46% at 100% full load. PF can also be satisfied above 0.987. The iTHD meet spec at full load 5.5KW (<5%@5.5 kW). As shown in Figure 4, The efficiency graph measured when the input voltage is from 208Vac to 277Vac. The peak efficiency is above 99.2% and the full load efficiency is above 98.4% and the iTHD under 5% in Figure5.

数字控制系统实现轻载至满载工况下TCM与CCM混合模态控制。当208~277Vac输入且10%至100%负载范围内，系统最高效率达10%轻载97.88%、满载超98.46%。PF亦可稳定高于0. 987。iTHD符合规范，在5.5kW满载工况下＜5%。如图4所示，208~277Vac输入时系统效率曲线显示：峰值效率＞99.2%，满载效率＞98.4%；图5验证满载iTHD稳定低于5%。

Figure 4: Efficiency diagram of different input voltage measurements

图4:不同输入电压测量的效率曲线图

Figure 5: iTHD diagram of different input voltage measurements

图5：不同输入电压测量的iTHD曲线图

Summary

总结

Higher power level PSU is a new trend for AI server driven by AI technology. The hybrid TCM/CCM control strategy in interleaved TTP PFCs offers a comprehensive solution for high-power AI server PSUs. By combining the strengths of both modes, this approach achieves higher efficiency, reduced ripple current, enhanced thermal management, and improved reliability. ST provides tailored design kits, 5.5 kW and 8 kW AI server PSUreference design and a comprehensive product portfolio to support the development of next-generation AI server PSUs.

高功率电源（PSU）是AI技术驱动的AI服务器新趋势。交错式TTP PFC中的混合TCM/CCM控制策略，为高功率AI服务器电源提供全栈解决方案。该方案融合双模优势，实现更高能效、更低纹波电流、更强热管理及更优可靠性。意法半导体提供定制设计套件（5.5kW/8kW AI服务器电源参考设计）及完整产品组合，赋能新一代AI服务器电源开发。

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