A Merged-Two-Stage LEGO-PoL Converter with Coupled Inductors for Vertical Power Delivery

Elasser, Youssef; Baek, Jae-Il; Chen, Minjie

doi:10.1109/ecce44975.2020.9236294

Cited by 12 publications

(6 citation statements)

References 9 publications

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“…This design is optimized to minimize the core and winding losses at an operating point of 20 A per phase. The designed core has higher density and lower dc resistance than the design presented in [3]. To enable vertical power delivery, the machined copper windings enter from the bottom of the core, make a 90 • rotation within the core, and exit from the top of the core to the output motherboard.…”

Section: Vertical Four-phase Coupled Inductormentioning

confidence: 99%

“…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: Vertical Four-phase Coupled Inductormentioning

confidence: 99%

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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“…This design is optimized to minimize the core and winding losses at an operating point of 20 A per phase. The designed core has higher density and lower dc resistance than the design presented in [3]. To enable vertical power delivery, the machined × × ; fully assembled converter next to a US Quarter and an Intel Itanium 9150 CPU.…”

Section: Vertical Four-phase Coupled Inductormentioning

confidence: 99%

“…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: 99%

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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“…Although the topologies reported in [5,6,7,8] can achieve IL,DC reduction without using additional inductors, they suffer from a limited voltage conversion ratio (VCR) range from 3:1 to 1:1, and therefore cannot fulfill the high step-down VCR scenarios, e.g., 12:1. The SC hybrid dual-path (DP) topologies presented in [9,10] realize an extended VCR range together with IL,DC reduction, which unfortunately degrades as VCR increases, indicating their incompatibility for high step-down application [11,12,13,14,15] (i.e., the DCR loss can still dominate the efficiency under a high VCR). This article has been accepted and published on J-STAGE in advance of copyediting.…”

Section: Introductionmentioning

confidence: 99%

A 12V-to-1V switched-capacitor-assisted hybrid converter with dual-path charge conduction and zero-voltage switching

Zhang

Yang

et al. 2021

IEICE Electron. Express

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This paper proposes a direct 12V-to-1V hybrid converter using a switched-capacitor-assisted (SCA) topology, featuring dual-path output current conduction to lower the inductor current. In contrast to the existing dual-path structures, the proposed topology realizes a high step-down conversion with efficiency improvement in heavy-load conditions. Besides, the converter further achieves an efficiency boost in light-load conditions using zero-voltage switching. Designed in a 180-nm SOI BCD process, the proposed converter regulates an output of 0.7~1.3V from a 12-V input with a peak efficiency of 92%. Under a loading current of 2A, it attains an efficiency over 84% at the 1-V output. Compared with the conventional buck, it achieves an improvement of 9.8% in peak efficiency and 13.6% in maximum-loading efficiency.

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A Merged-Two-Stage LEGO-PoL Converter with Coupled Inductors for Vertical Power Delivery

Cited by 12 publications

References 9 publications

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Vertical Stacked LEGO-PoL CPU Voltage Regulator

Vertical Stacked LEGO-PoL CPU Voltage Regulator

A 12V-to-1V switched-capacitor-assisted hybrid converter with dual-path charge conduction and zero-voltage switching

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