LEGO-PoL: A 48V-1.5V 300A Merged-Two-Stage Hybrid Converter for Ultra-High-Current Microprocessors

Baek, Jae-Il; Wang, Ping; Elasser, Youssef; Chen, Yenan; Jiang, Shuai; Chen, Minjie

doi:10.1109/apec39645.2020.9124564

Cited by 26 publications

(18 citation statements)

References 13 publications

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“…= 0. This mechanism holds the large-signal average of v C2 at 2 3 V in and the transient dynamics of the capacitor voltage follows a similar second-order transient dynamic (similar damping ratio and Q) as i L1 − i L3 and gradually damps to 2 3 V in following the same oscillation. V C2 will be automatically maintained at buck units high side switches is D, the large-signal average model of the system is:…”

Section: Appendix I Current Sharing and Voltage Balancingmentioning

confidence: 75%

“…This paper is a combination and extension of five previously published conference papers, "LEGO-PoL: A 93.1% 54V-1.5V 300A Merged-Two-Stage Hybrid Converter with a Linear Extendable Group Operated Pointof-Load (LEGO-PoL) Architecture" in IEEE COMPEL 2019 [1], "LEGO-PoL: A 48V-1.5V 300A Merged-Two-Stage Hybrid Converter for Ultra-High-Current Microprocessor" in IEEE APEC 2020 [2], "A Merged-Two-Stage LEGO-PoL Converter with Coupled Inductors for Vertical Power Delivery" in IEEE ECCE 2020 [3], "3D LEGO-PoL: A 93.3% Efficient 48V-1.5V 450A Merged-Two-Stage Hybrid Switched-Capacitor Converter with 3D Vertical Coupled Inductors" in IEEE APEC 2021 [4], and "Vertical Stacked 48V-1V LEGO-PoL CPU Voltage Regulator with 1A/mm 2 Current Density" in IEEE APEC 2022 [5]. This work was jointly supported by Google LLC and Intel Corporation.…”

Section: Introductionmentioning

confidence: 99%

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Vertical Stacked LEGO-PoL CPU Voltage Regulator

Baek

Elasser

Radhakrishnan

et al. 2022

IEEE Trans. Power Electron.

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This paper presents a 48 V-1 V merged-two-stage hybrid-switched-capacitor converter with a Linear Extendable Group Operated Point-of-Load (LEGO-PoL) architecture for ultra-high-current microprocessors, featuring 3-D stacked packaging and coupled inductors for miniaturized size, fast speed, and vertical power delivery. The architecture is highly modular and scalable. The switched-capacitor circuits are connected in series on the input side to split the high input voltage into multiple stacked voltage domains. The multiphase buck circuits are connected in parallel to distribute the high output current into multiple parallel current paths. It leverages the advantages of switched-capacitor circuits and multiphase buck circuits to achieve soft charging, current sharing, and voltage balancing. The inductors of the multiphase buck converters are used as current sources to soft-charge and soft-switch the switchedcapacitor circuits, and the switched-capacitor circuits are utilized to ensure current sharing among the multiphase buck circuits. A 780 A vertical stacked CPU voltage regulator with a peak efficiency of 91.1% and a full load efficiency of 79.2% at an output voltage of 1 V with liquid cooling is built and tested. The switched capacitor circuits operate at 286 kHz and the buck circuits operate at 1 MHz. It regulates output voltage between 0.8 V and 1.5 V through the entire 780 A current range. This is the first demonstration of a 48 V-1 V CPU voltage regulator to achieve over 1 A/mm 2 current density and the first to achieve 1,000 W/in 3 power density.

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Section: Appendix I Current Sharing and Voltage Balancingmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Baek

Elasser

Radhakrishnan

et al. 2022

IEEE Trans. Power Electron.

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“…= 0. This mechanism holds the large-signal average of v C2 at 2 3 V in and the transient dynamics of the capacitor voltage follows a similar second-order transient dynamic (similar damping ratio and Q) as i L1 − i L3 and gradually damps to 2 3 V in following the same oscillation. V C2 will be automatically maintained at This analysis can be extended and generalized for a LEGO-PoL converter with N submodules.…”

Section: Appendix I Current Sharing and Voltage Balancingmentioning

confidence: 75%

“…Future high performance computing systems (CPUs, GPUs, and TPUs) comprise billions of transistors switching at very fast speeds, and consume hundreds of amperes of current at very low voltage (e.g. This paper is a combination and extension of four previously published conference papers, "LEGO-PoL: A 93.1% 54V-1.5V 300A Merged-Two-Stage Hybrid Converter with a Linear Extendable Group Operated Point-of-Load (LEGO-PoL) Architecture" in IEEE COMPEL 2019 [1], "LEGO-PoL: A 48V-1.5V 300A Merged-Two-Stage Hybrid Converter for Ultra-High-Current Microprocessor" in IEEE APEC 2020 [2], "A Merged-Two-Stage LEGO-PoL Converter with Coupled Inductors for Vertical Power Delivery" in IEEE ECCE 2020 [3], and "3D LEGO-PoL: A 93.3% Efficient 48V-1.5V 450A Merged-Two-Stage Hybrid Switched-Capacitor Converter with 3D Vertical Coupled Inductors" in IEEE APEC 2021 [4]. [5], [6].…”

Section: Introductionmentioning

confidence: 97%

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Chen¹

2021

Preprint

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<div>This paper presents a 48 V–1 V merged-two-stage hybrid-switched-capacitor converter with a Linear Extendable Group Operated Point-of-Load (LEGO-PoL) architecture for ultra-high-current microprocessors, featuring 3-D stacked packaging and coupled inductors for miniaturized size and vertical power delivery. The architecture is highly modular and scalable. The switched capacitor circuits are connected in series on the input side to split the high input voltage into multiple stacked voltage domains. The multiphase buck circuits are connected in parallel to distribute the high output current into multiple parallel current paths. It leverages the advantages of switched capacitor circuits and multiphase buck circuits to achieve soft charging, current sharing, and voltage balancing. The inductors of the multiphase buck converters are used as current sources to soft-charge and soft-switch the switched-capacitor circuits, and the switched-capacitor circuits are utilized to ensure current sharing among the multiphase buck circuits. A 780 A vertical stacked CPU voltage regulator with a peak efficiency of 91.1% and a full load efficiency of 79.2% at an output voltage of 1 V with liquid cooling is built and tested. This is the first demonstration of a 48 V–1 V CPU voltage regulator to achieve over 1 A/mm2 current density and the first to achieve 1,000 W/in3 power density. It regulates output voltage between 0.8 V and 1.5 V through the entire 780 A current range.</div>

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“…In non-isolated high conversion ratio dc-dc converter applications, switched-capacitor circuits are very attractive due to their high efficiency and high power density. Soft-charging techniques can eliminate the charge sharing losses in switched capacitors, allowing switched capacitor circuits to operate at lower frequencies with reduced switching loss and improved efficiency, with a limited capacitor size [11], [18], [20].…”

Section: Introductionmentioning

confidence: 99%

High Frequency Multicell Cascaded Quasi-Square-Wave Boost Converter

Yuan

Chen

Yang

et al. 2020

2020 IEEE 21st Workshop on Control and Modeling for Power Electronics (COMPEL)

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This paper presents a multicell cascaded quasisquare-wave (MCQSW) boost converter for non-isolated DC-DC applications with high voltage conversion ratios. The MCQSW boost converter is designed to operate at high frequencies and can achieve zero voltage switching (ZVS), soft charging, current sharing, and automatic voltage balancing. In the MCQSW converter, many boost cells are connected in parallel in series to distribute the high input current; multiple output capacitors are stacked in series to achieve high output voltage. The multicell parallelinput series-output configuration can significantly extend the voltage conversion ratios of the traditional QSW boost converters while maintaining low power conversion stress and enable low input current ripple due to interleaving. The high-frequency ZVS operation is enabled by an analogy control circuitry which can operate up to a few MHz. A 700 kHz to 5 MHz, 15 V-180 V (1:12 conversion ratio), 250 W MCQSW converter was built to validate the effectiveness of the MCQSW converter achieving a peak efficiency of 91%.

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LEGO-PoL: A 48V-1.5V 300A Merged-Two-Stage Hybrid Converter for Ultra-High-Current Microprocessors

Cited by 26 publications

References 13 publications

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Vertical Stacked LEGO-PoL CPU Voltage Regulator

High Frequency Multicell Cascaded Quasi-Square-Wave Boost Converter

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