Voltage Regulator Module Research Articles

Modeling and Control of Quasi-Parallel Sigma DC–DC Converter for Single-Stage 48-V Voltage Regulator

With the improvement of data center processing performance, the voltage regulator module (VRM) structure of 48-V bus is being proposed more and more to improve the system efficiency and to reduce the cost of data center. For a 48–1.8-V VRM, a quasi-parallel configuration, the sigma converter, is shown to have a peak efficiency of 95.2% and a power density of 700 W/in3 <xref ref-type="bibr" rid="ref16" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">[16]</xref> . In order to accurately compensate the design of the sigma converter to meet the VRM requirements, a decoupling method is proposed in this article to construct a small-signal model of a quasi-parallel structure according to the interaction characteristics of duty cycle, output voltage, and input floating-point voltage during sigma operation. Based on this decoupling model, precise analytical expressions for various transfer functions are derived, such as control-to-output and output/input impedance, whose Bode plots are highly consistent with those in SIMPLIS simulation. In order to make the derived transfer function easy for compensation design, the control-to-output transfer function is simplified to standard zero-pole form. A voltage mode control design is provided and verified through the prototype verification board of sigma structure. Tests show that the compensation design based on the derived transfer function can achieve voltage regulation under different loads.

An Ultrahigh Step-Down DC–DC Converter Based on Switched-Capacitor and Coupled Inductor Techniques

In this article, high step-down dc–dc converters are widely employed in data center applications. Due to the higher step-down conversion ratio in the new generation 48 V voltage regulator module, a conventional buck converter is not suitable for such applications. To conquer this problem, a novel dc–dc converter is proposed in this article to achieve an ultrahigh step-down voltage conversion ratio for data centers. The nonisolated topology can be optimally designed to integrate both the switched-capacitor and coupled inductor techniques, which allows zero-voltage-switching (ZVS) of all active switches to be achieved and improves high efficiency. In addition, the converter presents the advantages of lower voltage stress, ultrahigh voltage gain, common ground, and simple control strategy. A comprehensive analysis of the steady-state analysis, derivation of voltage gain, voltage stress, and ZVS condition is presented in detail. Finally, a 30 W, 48-to-1 V experimental prototype is built and tested, which validates the ultrahigh step-down voltage gain and soft-switching characteristic of the proposed converter. The maximum efficiency of the prototype is 89.1% and the efficiency is 81.4% in full-load condition.

A Novel Integrated Matrix Magnetics for Isolated Single-Stage DC–DC Converter

With the development of data center, promotion for efficiency and power density of the voltage regulator module (VRM) is paid considerable attention. Isolated VRM is suitable for the high-conversion-ratio dc–dc application. However, isolated VRM has many magnetic components, which take up a large proportion of the total volume. In this article, a novel integrated matrix magnetics structure is proposed, which integrates two elemental transformers and four output inductors into a single core. By integrating several discrete magnetic components, the volume of passive components, and high-current interconnections are reduced, leading to high power density and high efficiency. The integrated matrix magnetics is employed in an isolated single-stage converter, which can provide high output current. In addition, primary switches can achieve zero-voltage-switching (ZVS), and synchronous rectifiers of secondary side can achieve ZVS and zero-current-switching, so efficiency can be further improved. Besides, equivalent output inductance, voltage conversion ratio and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</sub> calculation are derived to design the integrated matrix magnetics. Finally, a 48 V/1.8 V 144 W prototype of the isolated single-stage converter with integrated matrix magnetics is made and tested to verify the analysis.

Overview of Voltage Regulator Modules in 48 V Bus-Based Data Center Power Systems

The intermediate dc bus voltage in modern data center backend power supply is evolving from conventional 12 V to 48 V. It still requires the voltage regulator modules (VRM) to feed the terminal loads such as memory and computing units operating with very high current (&gt; 100 A/module) and very low logic voltage (0.8 V-1.8 V). This makes it challenging to optimize the design of load-side VRMs with quadrupled input voltage. This paper comprehensively reviews the state-of-the-art 48 V VRMs and categorizes them according to passive component utilization. The first category is inductive solution which is further divided into coupled-inductor-based converters and transformer-based converters. The second category named capacitive solution is further divided into resonant switched-capacitor-based converters (Resonant SCC) and hybrid switched-capacitor-based converters (Hybrid SCC). Typical topologies are discussed, analyzed and summarized to perform a comprehensive performance comparison, such that the characteristics of different VRMs can be manifested. Some design considerations are also given to facilitate the design of the practical prototypes. Moreover, opportunities and challenges in the future data center power system are presented to provide technical insights.

In-Place Evaluation of Powering and Signaling Within Fan-Out Multiple IC Chip Packaging

This article confirms the advantage of fan-out (FO) packaging in the electrical performance of power delivery among integrated circuit (IC) chips with the best use of land side capacitors (LSCs). On-chip in-place waveform measurements quantitatively evaluate the integrity of powering and signaling within FO wafer level packaging (FOWLP) multiple chip module (MCM) demonstrators, where a pair of IC chips are assembled with LSCs with different sizes and structures. The IC chip incorporates an array of 12 digital cores and on-chip waveform monitor (OCM) circuits. Each digital core consists of a low-voltage differential signaling (LVDS) transceiver channel that is backed by a static random access memory (SRAM)-based built-in self test (BIST) module and supplied by an on-chip voltage regulator module (VRM). The LSCs are placed on the bottom side of an FO interposer and inserted between the output of VRM and the ground plane almost ideally with the shortest length of physical traces. A Si membrane capacitor of 10 nF sustains the lowest power line impedance over the frequency range of 2.0 GHz more constantly than a multilayer ceramic counterpart, and attenuates the high-order harmonic frequency components to the clocking frequency at 750 MHz. The leverage of LSCs in powering also improves signaling and helps achieve the wider eye openings in LVDS channels. The implications are elaborated for the capacitor selections with respect to the physical types of capacitors, the size of capacitances, and the level of shares in power delivery among digital cores, all toward the higher level of integrity in powering and signaling in FOWLP MCMs.

The magnetic field self-display system of coupler for wireless power transfer systems based on magnetic structure factor

The magnetic field surrounding wireless power transfer (WPT) systems is difficult for the general public to discern in practice. To address this problem, a system that only measures the current in the coils for transferring and receiving to get the coupler’s magnetic field strength at a specific geographic location in space is proposed. The system includes a current transformer, inductive power-harvesting device, rectifier module, voltage regulation module, microprocessor, AD module, and display module. Due to the fixed mechanical structure and position of the coupler when working, the calculation model of the magnetic field of the coupler is established, and the magnetic structure factor based on the mechanical structure of the coupler is defined. The system can obtain power and operate based on the inductive power harvesting principle without damaging the WPT system structure. It also can realize the convenient display of the magnetic field and avoid the dependence on professional instruments when measuring the magnetic field of the coupler. In addition, it is easy to implement in practice.

A Reconfigurable Single-Stage Asymmetrical Full-Wave Step-Down Rectifier for Bidirectional Device-to-Device Wireless Fast Charging

This article proposes a reconfigurable single-stage regulating asymmetrical full-wave step-down rectifier (SDR) for fast wireless charging. The SDR is reconfigurable into a step-up power amplifier (SUPA) for device-to-device (D2D) wireless charging. The SDR and SUPA can have a direct connection with the battery without an additional voltage regulator module (VRM). With the single-stage structure, the transmitting (TX) and receiving (RX) ac voltages across the resonant coil can be boosted, which greatly reduces the coil currents and losses, improving the D2D charging power. A reconfigurable controller for the TX/RX mode selection, as well as the switching timing control, is designed. The chip is fabricated in 0.35-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> CMOS that contains 20-V devices. For the asymmetrical operation, one GaN device is used for the high current path. Also, zero-voltage switching (ZVS) is realized for all the power transistors with one small (180 nH in the 4015 package) power inductor. The bidirectional D2D WPT system achieves a maximum charging power of 5.1 W with a D2D total efficiency of 46.3&#x0025; and a charging distance of 1.6 cm. Finally, the peak total efficiency is 51.4&#x0025; with a charging power of 3.4 W and a charging distance of 1 cm.

Topology-Based Accurate Modeling of Current-Mode Voltage Regulator Modules for Power Distribution Network Design

Power distribution network (PDN) is essential in electronic systems to provide reliable power for load devices. Thus, modeling of PDNs in printed circuit boards and packages has been extensively studied in the past few decades. However, with the higher integration levels and operation bandwidths of modern voltage regulator module (VRM), there lacks an accurate model for transient load responses based on the widely used current-mode control topology. In this work, a topology-based behavior model, including both the power stage and control loops, is developed for the current-mode buck VRM. A novel method is also proposed to unify the modeling of the continuous and discontinuous conduction modes for transient load responses. Through the measurement-based characterization, the model parameters are optimized to match with the actual design. Furthermore, this model can be applied to both the time-domain and frequency-domain circuit simulations to predict the voltage droop and output impedance, respectively. The accuracy of the model is validated using an evaluation board containing the single-phase and multiphase VRMs. The proposed model for current-mode control VRM can be easily cascaded with other PDN components to enable a combined PDN analysis.

Design and development of multiphase buck converters for voltage regulator modules

&lt;p&gt;Modern microprocessors in high-power applications require a low input voltage and a high input current, necessitating the use of multiphase buck converters. As per microprocessor computing complexity, the power requirements of the switching converter will also be more important and will be increasing as per load demand. Previous studies introduced some methods to achieve the advantages associated with multiphase regulators. This paper presents an effective closed closed-loop control scheme for multiphase buck converters that reduces ripple and improves transient response. It is suitable for applications that require regulated output voltage with effectively reduced ripple. The analysis began with a simulation of the entire design using the OrCAD tool, followed by the construction of a hardware setup. Experiments on a 200 Khz, 9 V, 12 A, 2-phase buck voltage regulator were conducted and the proposed experiment found to be useful.&lt;/p&gt;

Design and Test of a Spoke-like Piezoelectric Energy Harvester.

With the development of industry IoT, microprocessors and sensors are widely used for autonomously transferring information to cyber-physics systems. Massive quantities and huge power consumption of the devices result in a severe increment of the chemical batteries, which is highly associated with problems, including environmental pollution, waste of human/financial resources, difficulty in replacement, etc. Driven by this issue, mechanical energy harvesting technology has been widely studied in the last few years as a great potential solution for battery substitution. Therefore, the piezoelectric generator is characterized as an efficient transformer from ambient vibration into electricity. In this paper, a spoke-like piezoelectric energy harvester is designed and fabricated with detailed introductions on the structure, materials, and fabrication. Focusing on improving the output efficiency and broadening the pulse width, on the one hand, the energy harvesting circuit is optimized by adding voltage monitoring and regulator modules. On the other hand, magnetic mass is adopted to employ the magnetic field of repulsive and upper repulsion–lower attraction mode. The spoke-like piezoelectric energy harvester suggests broadening the frequency domain and increasing the output performance, which is prepared for wireless sensors and portable electronics in remote areas and harsh environments.

Interactional Influence Analysis of DC Bus Voltage Vs Servo Systems and Stabilization Technology for Aerospace Combined Power Supply Systems

With rapid developments in aerospace science and technology, higher requirements are being placed on the control accuracy of aircraft. As the power source of aircraft servo systems, the power quality of the combined power supply system directly affects the control accuracy of aircraft. Therefore, it is crucial to improve the performance of this combined power supply system. In this paper, a method based on non-singular terminal sliding mode control (NTSMC) is proposed to suppress the DC bus voltage fluctuation of the combined power supply system, which is caused by servo motor loads. Firstly, the mutual influences of the servo motor running state and the DC bus voltage on one another are analysed. Then, the mathematical model of the DC bus voltage regulation module, based on a bidirectional DC-DC converter and ultracapacitor, is established. The NTSMC algorithm is adopted, and the sliding mode surface and control law are designed to suppress the DC bus voltage fluctuation of the combined power supply system. Finally, simulation and experimental research are carried out to verify the effectiveness of the method. The results show that the proposed method can effectively suppress the fluctuation of DC bus voltage, and that NTSMC is superior to the traditional PID control method for aerospace combined power supply systems.

Multifunctional poly(vinyl alcohol)/Ag nanofibers-based triboelectric nanogenerator for self-powered MXene/tungsten oxide nanohybrid NO2 gas sensor

Triboelectric nanogenerators (TENGs) have broad application prospects in flexible electronics and self - powered sensing devices. In this paper, a poly(vinyl alcohol)/silver (PVA/Ag) nanofibers - based TENG was developed for human respiration, movement and harmful gas monitoring. The peak - to - peak value of open - circuit voltage and powered density from the wind - driven PVA/Ag - based TENG can reach up to 530 V and 359 mW/m 2 , respectively. Constant voltage output can be achieved at a large range of wind speeds (2.5–8 m/s) and humdity levels (30–65% RH) by integrating a voltage regulator module with the wind - driven TENG, which provides a feasible solution for the wind - driven TENG as a stable voltage source under different wind strength. The self - powered Ti 3 C 2 T x MXene/WO 3 sensor driven by TENG has an excellent response (ΔUs/Us a = 510% @ 50 ppm) for NO 2 gas at room temperature, which is 15 times larger than that of the resistive MXene/WO 3 sensor. A multifunctional self - powered detection system was developed by integrating four TENGs with a gas sensor for detection of wind direction and wind - borne NO 2 , which can be used to trace the source of harmful gases. The wind - driven self - powered sensor system provides a sustainable and maintenance - free detection platform, which has great application potential in the field of environmental monitoring. • A wind-driven triboelectric nanogenerator (TENG) based on poly(vinyl alcohol)/Ag nanofibers film was fabricated. • The PVA/Ag-based TENG was demonstrated for human respiration and movement stimulation monitoring. • A high-performance Ti 3 C 2 T x MXene/tungsten oxide nanofibers-based NO 2 sensor was fabricated. • A multifunctional self-powered detection system was developed for detection of wind direction and wind-borne NO 2 .

System-level Early-stage Modeling and Evaluation of IVR-assisted Processor Power Delivery System

Despite being employed in numerous efforts to improve power delivery efficiency, the integrated voltage regulator (IVR) approach has yet to be evaluated rigorously and quantitatively in a full power delivery system (PDS) setting. To fulfill this need, we present a system-level modeling and design space exploration framework called Ivory for IVR-assisted power delivery systems. Using a novel modeling methodology, it can accurately estimate power delivery efficiency, static performance characteristics, and dynamic transient responses under different load variations and external voltage/frequency scaling conditions. We validate the model over a wide range of IVR topologies with silicon measurement and SPICE simulation. Finally, we present two case studies using architecture-level performance and power simulators. The first case study focuses on optimal PDS design for multi-core systems, which achieves 8.6% power efficiency improvement over conventional off-chip voltage regulator module– (VRM) based PDS. The second case study explores the design tradeoffs for IVR-assisted PDSs in CPU and GPU systems with fast per-core dynamic voltage and frequency scaling (DVFS). We find 2 μs to be the optimal DVFS timescale, which not only reaps energy benefits (12.5% improvement in CPU and 50.0% improvement in GPU) but also avoids costly IVR overheads.

A State-Space-Based Method to Model Vccin Feedthrough Noise in Microprocessors With Fully Integrated Voltage Regulators

Modern high-performance server microprocessors need to integrate multiple intellectual property (IP) blocks in a single chip to achieve higher performance. Due to the diverse supply voltage requirements of these IP blocks, their supply voltages are generated locally on the chip using fully integrated voltage regulators (FIVRs). FIVR is designed using on-chip power bridges, bridge drivers, control circuits, on-chip metal–insulator–metal (MIM) capacitors, package inductors, and package power planes. The input power supply (Vccin) of all the FIVRs is shared to minimize the platform cost and is generated using a voltage regulator module (VRM) on the motherboard. The noise coupling between FIVRs due to the common input supply is referred to as the Vccin feedthrough noise. The existing method of modeling the Vccin feedthrough noise is based on circuit simulation. Circuit models are highly complex as different components such as the FIVR power bridges, bridge drivers, MIM capacitors, package inductors, package power planes, and the Vccin network need to be modeled. Convergence issues are very frequent in full chip circuit simulations and it typically takes many iterations. Hence design optimization is difficult to carry out using circuit simulations. In this article, a state-space-based time-domain method is proposed to model the Vccin feedthrough noise based on G-parameters and S-parameters of the FIVR and the Vccin network. The state-space models are generated using the vector-fitting algorithm. The proposed method simplifies the construction of the Vccin feedthrough models and improves the convergence time.

The study on the effect of voltage ripple on multiphase buck converters with phase shedding control scheme for SCADA applications

Voltage regulator modules (VRM) need to have low output voltage ripple and tight efficiency to power advanced microprocessors. This paper explains a phase shedding technique to enhance efficiency and its impact on output voltage ripple. In this study, analysis was done on a 4-phase buck converter which is having an input voltage of 45-65 V and delivers an output of 9 V, 12A with a switching frequency of 200Khz. The phase shedding control scheme is suitable for applications such as power sources for programmable logic controllers, which is a part of SCADA systems, which requires a low voltage and high current power supply. Working of a multiphase buck converter with phase shedding is modelled and verified using Matlab/Simulink software. The simulation results show the effect of the phase shedding technique on efficiency in varying load conditions and the effect of an increase of the voltage ripple at the output.

A new soft‐switching high step‐down DC‐DC converter for voltage regular module application

This study proposes a high step-down DC-DC converter with minimum elements. In the proposed converter, soft switching condition is provided with only one auxiliary switch, which simplifies the structure of the converter. Leakage inductor energy is used to create a zero voltage condition; so the mutations created by this inductor are neutralised. The control of the auxiliary switch is complementary to the main switch, which does not require a new and complex control circuit. Due to low voltage gain, the proposed converter is suitable for use in voltage regulator modules. The proposed converter is completely analysed. To confirm the theoretical analysis, an experimental sample is made and tested at 15 W and the results are presented. Also, the efficiency of the proposed converter at full load is 97.5%.

Coastal buoy data acquisition and telemetry system for monitoring oceanographic and meteorological variables in the Gulf of Mexico

This paper presents a data acquisition and telemetry system designed and built to monitor oceanographic and meteorological parameters. A voltage regulator and readout module was designed for the reading of data from a set of dedicated commercial sensors and to continuously monitor the voltage level of the power supply. In order to monitor the measured parameters and the status of the buoy remotely, a data string was transmitted every hour using an Iridium satellite transceiver. The described system was implemented and tested in four coastal oceanographic buoys that were deployed and operated in remote sites in the Gulf of Mexico (GoM) for several months in 2016. The data recorded by the buoys is used to describe the oceanographic and meteorological conditions at each site. The system proved to be reliable for long-term monitoring at offshore sites, requiring only minor corrective maintenance during their operation in the field.

A 3-Phase Resonant Switched-Capacitor Converter for Data Center 48-V Rack Power Distribution

Since the power consumption of data centers keeps increasing, a 48-V rack power distribution system replaces the conventional 12-V power bus to reduce the power delivery IR losses. Meanwhile, the 48 V needs conversion into 1 V or lower at the point-of-load for microprocessors. A 48V-to-12V DC-DC converter can serve as a first stage between the huge gap of 48V-to-1V, in a two-stage voltage regulator module (VRM). Thus, this paper presents a 3-phase resonant switched-capacitor ( 3Φ-ReSC) converter as the first stage of the VRM. Different from the reported solutions, 3-phase resonant operation reduces the current stress across each small-size GaN switch, and thus improves the power conversion efficiency. In addition, we also present the theoretical analysis and design procedures for the 3Φ-ReSC converter. We demonstrated the proposed 3Φ-ReSC converter with a 98% peak power efficiency at an output current of about 1 A, with a maximum output current of 10 A.

MICROPROCESSOR SYSTEM FOR INVESTIGATION OF SENSOR CHARACTERISTICS ON THE BASIS OF POROUS SILICON

Development of integrated sensors is a promising scientific and technical direction to create components for measurement and information systems. Among the different types of analyser one of the places are occupied by sensors of hydrogen containing compounds in gaseous and liquid condition (especially poisonous and carcinogenic). Fixing the presence of a substances in the gas or liquid environment is an actual task for scientific, industrial and medical application areas. The main goal of this paper an inexpensive microprocessor system for measuring and analyzing electrical properties of nanocomposite sensing material such as porous silicon on the base of current and capacity-voltage characteristics and its hardware and software applying is represented. The microprocessor system is designed for measuring sensors current-voltage and capacity-voltage characteristics based on porous silicon and nanocomposite structures and consists of the following units: power supply unit, DC voltage regulator, control and measurement module, RLC-meter E7-22, UART/USB and RS232/USB converters, measuring cell, PC. The software of the microprocessor system for measuring consists of the software for the control and measurement module implemented on the Atmega 128 microcontroller and the main device management software for the PC. The main program algorithm and software are implemented in the C# programming language in the Visual Studio 2017 environment The results of the comparison allow us to conclude that the implemented modules of the microprocessor system for sensors I-V- and C-V characteristics testing can be used in the development of portable environmental monitoring devices, to study porous silicon sensors using them. Keywords — porous silicon, nanocomposite; sensor, microcontroller, microprocessing system, current-voltage characteristic

Analysis and Implementation of a Single-Stage Transformer-Less Converter With High Step-Down Voltage Gain for Voltage Regulator Modules

A novel transformer-less topology with high step-down voltage gain is proposed for low-voltage high-current point-of-load voltage regulator modules (VRMs). The proposed topology consists of three capacitors, two inductors, three active switches, and two synchronous rectifiers. It triples the effective duty-ratio and lowers the voltage stresses across active switches compared with conventional buck topologies. Converters based on the topology have a potential benefit of achieving high power density and can be capable of delivering high current to the output by two interleaving phases. Small inductance and capacitance are only needed by using interleaving technology, which results in very fast dynamic response to large load changes. A 60 W, 48-1.8 V prototype is built to verify the performance of the proposed topology.