Integrated Voltage Regulator Research Articles

Enabling Wide Autonomous DVFS in a 22 nm Graphics Execution Core Using a Digitally Controlled Fully Integrated Voltage Regulator

A digitally-controlled fully integrated voltage regulator (IVR) enables wide autonomous DVFS in a 22 nm graphics execution core. Part of the original power header is converted into a hybrid power stage to support digital low-dropout (DLDO), and switched-capacitor voltage regulator (SCVR) modes, in addition to the original bypass and sleep modes. Using voltage sensing, tunable replica circuit, or a core warning signal, the IVR detects and quickly responds to fast voltage droops to support fast dynamic workload changes without performance degradation. In a prototype, a 3D graphics execution core is powered up by the proposed hybrid IVR demonstrating measured 26% and 82% reduction in core energy in the turbo and the near-threshold voltage (NTV) modes, respectively. The total area overhead of the proposed hybrid IVR is 4% of the core compared to 2% from the original power header. Our digitally assisted control for the droop response shows ${\sim}$ 75% core frequency improvement at 0.84 V.

A Subthreshold ARM Cortex-M0+ Subsystem in 65 nm CMOS for WSN Applications with 14 Power Domains, 10T SRAM, and Integrated Voltage Regulator

The Internet of Things (IoT) is widely predicted to comprise billions of connected devices, many of which will be wireless sensor nodes (WSN). Energy efficiency is a huge challenge here, followed by node cost and ease of software (SW) development. Addressing all of the above, this paper presents an 11.7 pJ/cycle subthreshold ARM Cortex-M0+ WSN processing subsystem implemented in low-leakage 65 nm CMOS. Voltage and frequency scalability is from 850 nW active power at 250 mV to 66 MHz above 900 mV, with a fully integrated 82% peak-efficiency voltage regulator for direct-battery operation, and supporting 80 nW CPU and RAM state-retention power gating for SW transparent leakage reduction. SW and system optimization approaches are described and a $2.94\;\boldsymbol{\upmu}{\text{W}}$ SW ECG workload is presented.

A Rational-Conversion-Ratio Switched-Capacitor DC-DC Converter Using Negative-Output Feedback.

Switched-capacitor (SC) DC-DC converters have several advantages over inductive DC-DC converters in that they are easily integrated on-chip and can scale to desired power levels, rendering themselves promising for integrated voltage regulators, especially for small, low-power systems. However, many SC DC-DC converters offer only a few conversion ratios, limiting their use for systems in which either the input or output voltages vary. This is particularly important in wireless systems where battery voltage degrades slowly. [1] proposed a technique to reconfigure cascaded SC converters to achieve arbitrary binary ratios: p/2N, 0 90% efficiency when downconverting from 2V to a 1.1-to-1.86V output voltage range.

Package Inductors for Intel Fully Integrated Voltage Regulators

Intel fourth-generation and fifth-generation Core microprocessors are powered by high-frequency integrated switching voltage regulators. The inductors required to implement these regulators are constructed using the routing layers of conventional organic flip chip packaging. This paper provides an overview of the construction of these inductors including representative results from production packages. Measured inductors reported in this paper span from 1 to 6.7 nH under 2.4 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and achieve Q of up to 24 at 140 MHz (the switching frequency).

The Xeon® Processor E5-2600 v3: a 22 nm 18-Core Product Family

The next generation enterprise Xeon server processor maximum configuration supports 18 dual-threaded 64 bit Haswell cores, 45 MB L3 cache, 4 DDR4-2133 MHz memory channels, 40 8 GT/s PCIe lanes, and 40 9.6 GT/s QPI lanes. The processor has 5.56 B transistors on a 31.9 mm × 20.8 mm die in Intel's Hi-K metal-gate tri-gate 22 nm CMOS technology with 11 metal layers and achieves up to 33% performance boost. The design supports a wide range of configurations including thermal design power ranging from 55 to 160 W and frequencies ranging from 1.6 to 3.7 GHz. Key architectural innovations include the addition of AVX2 technology, DDR4, and fully integrated voltage regulators (FIVR) that enable per core p-states and uncore frequency scaling.

The 12-Core POWER8™ Processor With 7.6 Tb/s IO Bandwidth, Integrated Voltage Regulation, and Resonant Clocking

POWER8™ is a 12-core processor fabricated in IBM's 22 nm SOI technology with core and cache improvements driven by big data applications, providing 2.5× socket performance over POWER7+™. Core throughput is supported by 7.6 Tb/s of off-chip I/O bandwidth which is provided by three primary interfaces, including two new variants of Elastic Interface as well as embedded PCI Gen-3. Power efficiency is improved with several techniques. An on-chip controller based on an embedded PowerPC™ 405 processor applies per-core DVFS by adjusting DPLLs and fully integrated voltage regulators. Each voltage regulator is a highly distributed system of digitally controlled microregulators, which achieves a peak power efficiency of 90.5%. A wide frequency range resonant clock design is used in 13 clock meshes and demonstrates a minimum power savings of 4%. Power and delay efficiency is achieved through the use of pulsed-clock latches, which require statistical validation to ensure robust yield.

Evaluating Adaptive Clocking for Supply-Noise Resilience in Battery-Powered Aerial Microrobotic System-on-Chip

A battery-powered aerial microrobotic System-on-Chip (SoC) has stringent weight and power budgets, which requires fully integrated solutions for both clock generation and voltage regulation. Supply-noise resilience is important yet challenging for such SoC systems due to a non-constant battery discharge profile and load current variability. This paper proposes an adaptive-frequency clocking scheme that can tolerate supply noise and improve performance when implemented with an integrated voltage regulator (IVR). Measurements from a `brain' SoC, implemented in 40 nm CMOS, demonstrate 2 × performance improvement with adaptive-frequency clocking over conventional fixed-frequency clocking. Combining adaptive-frequency clocking with open-loop IVR extends error-free operation to a wider battery voltage range (2.8 to 3.8 V) with higher average performance.

Coupled Inductors With Crossed Anisotropy ${\rm CoZrTa/SiO}_{2}$ Multilayer Cores

Four-turn coupled (flux-closed) inductor structures have been fabricated and tested for use in high-power-density integrated voltage regulator (IVR) applications. Our solenoid-like structure is comprised of a laminated magnetic core of four rungs surrounded by four Cu windings creating four coupled inductors. The magnetic core is made of laminations of ultra-high-vacuum-sputtered [5 nm Ta/200 nm Co91.5Zr4.0Ta4.5(CZT)/7 nm SiO2] repeated 20 times. Individual CZT layers are deposited under a magnetic bias to induce uniaxial anisotropy. The quad-coupled inductor shows a frequency response with a measured self-inductance of 7.4 nH for one inductor sustained up to 100 MHz and roll-off to half this low-frequency value at ~450 MHz. This inductance is more than 65× higher than what would be calculated from an air-core inductor of equivalent geometry.

PLC-Based Integrated Voltage Regulator Thermostat Power Source

The PLC-based integrated voltage regulator thermostat power source is constituted by the voltage regulator, the controller and the electric heater. It can achieve a moderate control of the electric heater, protect the power grid and load from disturbed and reduce the volatility of the test chamber studio. The system has simple power regulation line, stable performance, high reliability, and can be widely applied in the area of industrial automation and control.

A 2.5D Integrated Voltage Regulator Using Coupled-Magnetic-Core Inductors on Silicon Interposer

An integrated voltage regulator (IVR) is presented that uses custom fabricated thin-film magnetic power inductors. The inductors are fabricated on a silicon interposer and integrated with a multi-phase buck converter IC by 2.5D chip stacking. Several inductor design variations have been fabricated and tested. The best performance has been achieved with a set of eight coupled inductors that each occupies 0.245 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and provides 12.5 nH with 270 mΩ DC. With early inductor prototypes, the IVR efficiency for a 1.8 V:1.0 V conversion ratio peaks at 71% with FEOL current density of 10.8 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and inductor current density of 1.53 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . At maximum load current, 69% conversion efficiency and 1.8 V:1.2 V conversion ratio the FEOL current density reaches 22.6 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and inductor current density reaches 3.21 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Application of a high efficient voltage regulation system with MPPT algorithm

In this study, an integrated voltage regulation system including Maximum Power Point Tracking Algorithm (MPPT) is introduced to store and efficient use of the energy produced by renewable sources. A dsPIC is used as the main controller to obtain a rapid and stable decision-making system and to decrease the cycle time of the MPPT operation. In order to minimize the oscillations on the output voltage, a cuk converter is used that can be operated as both buck and boost modes. Thus, efficiency of the system has been increased considerably by storing the energy consistently. The experimental results validates that the system developed operates highly stable and is faster than the similar ones presented in recent literature.

A Switched-Inductor Integrated Voltage Regulator With Nonlinear Feedback and Network-on-Chip Load in 45 nm SOI

A four-phase integrated buck converter in 45 nm silicon-on-insulator (SOI) technology is presented. The controller uses unlatched pulse-width modulation (PWM) with nonlinear gain to provide both stable small-signal dynamics and fast response (~700 ps) to large input and output transients. This fast control approach reduces the required output capacitance by 5× in comparison to a conventional, latched PWM controller at a similar operating point. The converter switches package-integrated air-core inductors at 80 MHz and delivers 1 A/mm2 at 83% efficiency and 0.66 conversion ratio. A network-on-chip (NoC) serves as a realistic digital load along with a programmable current source capable of generating load current steps with slew rate of ~1 A/100 ps for characterization of the control scheme.

A fully on-chip area-efficient CMOS low-dropout regulator with fast load regulation

Fully integrated voltage regulators with fast transient response and small area overhead are in high demand for on-chip power management in modern SoCs. A fully on-chip low-dropout regulator (LDO) comprised of multiple feedback loops to tackle fast load transients is proposed, designed and simulated in 90 nm CMOS technology. The LDO also adopts an active frequency compensation scheme that only needs a small amount of compensation capacitors to ensure stability. Simulation results show that, by the synergy of those loops, the LDO improves load regulation accuracy to 3 μV/mA with a 1.2 V input and 1 V output. For a 100 mA load current step with the rise/fall time of 100 ps, the LDO achieves maximum output voltage drop and overshoot of less than 95 mV when loaded by a 600 pF decoupling capacitor and consumes an average bias current of 408 μA. The LDO also features a magnitude notch in both its PSRR and output impedance that provides better suppression upon the spectral components of the supply ripple and the load variation around the notch frequency. Monte Carlo simulations are performed to show that the LDO is robust to process and temperature variations as well as device mismatches. The total area of the LDO excluding the decoupling capacitor is about 0.005 mm2. Performance comparisons with existing solutions indicate significant improvements the proposed LDO achieves.

Analysis and Design of Voltage Regulator With Adaptive FET Modulation Scheme and Improved Efficiency

This paper presents a load adaptive voltage regulator that achieves high efficiency extended to light and heavy load regions. The presented method is named as adaptive field effect transistor modulation (AFM) since multiple field effect transistors (FETs) with different characteristics (different sizes) are applied in parallel such that the number of driven FETs and their respective gate driving voltage are adaptive to load current. The capability of adaptive modulation of FETs' parasitic charges and resistances along with adaptive gate driving voltage allows the optimization of equivalent FET characteristics over a wide load range. Moreover, the AFM operation under load dynamic conditions is studied and a scheme is proposed. The AFM operates at a fixed switching frequency for almost the entire load range. Therefore, it has no impact on the operation and the dynamic performance of a conventional buck VR, and it is easy to implement. In this paper, the concept, design and theoretical analysis of the AFM are discussed and verified experimentally. Even though the simulation and experimental works design example given in this paper is for lower power and low voltage converter with discrete components for demonstration purposes, the AFM may have better improvement in higher power and/or higher voltage applications and in integrated voltage regulators.

Integrated voltage regulator SPICE model

An integrated voltage regulator SPICE model is presented. The model takes into account the main electrical characteristics (dropout voltage and quiescent current); the thermal effects of the electrical variables; and one of the electrical effects of the junction temperature, the thermal shutdown, a protection system used by many commercial devices.

95/03682 A predictive integrated voltage regulator and power system stabilizer

95/03682 A predictive integrated voltage regulator and power system stabilizer

A predictive integrated voltage regulator and power system stabilizer

An integrated voltage regulator and power system stabilizer based on one step ahead prediction is presented. The fixed parameter predictive control scheme is shown capable of providing consistently good voltage response and contribution to system damping over a wide range of operating conditions anti system configuration. This is in contrast to the case with conventional automatic voltage regulator and power system stabilizer where performance varies widely with the operating situation and can even cause system instability.

Voltage regulator with additional watchdog function

An integrated voltage regulator for use in automotive systems that incorporate a microcontroller is described. It can be used to supply systems ranging from ignition control to top-of-the-range car radios. One of its two outputs provides 5 V/50 mA and the other drives an external pnp transistor which delivers an adjustable output voltage. Additional control functions are a watchdog function and input/output monitoring. >

Simple temperature controller using the 723 integrated voltage regulator

A general-purpose temperature controller based entirely on the 723 integrated voltage regulator is described. It is very compact in size (20*20*30 mm3), does not create any electric disturbances during its functioning and is easy to build and install. The controller's supply can be in the range 9.5-40 V, the efficiency is close to 100%, the electronic circuit is highly reliable and cheap. With a conventional diode as a temperature sensor the temperature controller offers +or-0.03 K h-1 stability. When necessary, improved stability can be achieved using more sensitive temperature sensors.

Simple temperature controller

A dc-operated instrument intended for precise temperature control of small air-filled enclosures is described. An integrated voltage regulator is employed to control the output from the heater element in a continuous manner giving a short-term temperature stability better than ±0.02°C. The regulated temperature is adjustable, and the exact temperature is determined by the setting of a potentiometer, or alternatively the instrument can be remotely controlled by an external voltage source.