A Hysteretic Control Method for Multiphase Voltage Regulator

Lee, Kisun; Lee, F.C.; Xu, Ming

doi:10.1109/tpel.2009.2030804

Cited by 41 publications

(6 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, K. Lee in [3] uses a non-interaction principle, where both loops are designed and tuned separately. When the frequency loop UGB (Unity Gain Bandwidth) is low, it obviously takes much more time to recover after a transient in comparison with the high UGB setting.…”

Section: Pll Designmentioning

confidence: 99%

“…Interleaving and phase-shedding techniques are pillars that help to improve efficiency and ripple cancellation effect. Several works have been recently focused on the hysteretic mode controlled SMPS (Switched-Mode Power Supply) converters [1][2][3][4][5][6]. This type of control grows in popularity for fast transient response.…”

Section: Introductionmentioning

confidence: 99%

“…The traditional approach described in [2], [5] uses the frequency loop adjusting the delay of the main comparator. The comparator hysteresis band is adjusted in another approach mentioned in [3]. Both approaches lead to switching frequency control.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

Jelinek¹,

Jakovenko²

2017

RADIOENGINEERING

View full text Add to dashboard Cite

Section: Pll Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

Jelinek¹,

Jakovenko²

2017

RADIOENGINEERING

View full text Add to dashboard Cite

“…Phase-plot portraits [2], sliding-mode theory [3]- [5], state-space averaging [6]- [7], and circuit averaging [8]- [12] help, but the equations they generate are often abstract and difficult to relate to circuit operation, to inductor-current and outputvoltage ripples, response time, and others. This is why engineers ultimately over-size inductors or capacitors, and in so doing, counter their own miniaturization efforts.…”

Section: Switched-inductor Convertersmentioning

confidence: 99%

Stability analysis & design of hysteretic current-mode switched-inductor buck DC-DC converters

Solis

Rincón-Mora

2013

2013 IEEE 20th International Conference on Electronics, Circuits, and Systems (ICECS)

View full text Add to dashboard Cite

Battery-supplied systems demand fast, power efficient, and compact power supplies. Although linear regulators are quick and small, tiny batteries cannot sustain their losses for long. Pulse-width-modulated (PWM) switchers are considerably more efficient, but also slower. Luckily, hysteretic converters can respond within one switching cycle. Stabilizing the system for maximum speed with a hysteretic inductor-current loop, however, which is not linear, is not straightforward. This paper shows how load dumps delay the response of the hysteretic oscillator that the current loop implements. Knowing the worse-case dump and the delay it causes reveals the lowest output capacitance that maintains stable operation at maximum speed. The converter designed here can therefore recover, as predicted, from 100-mA load dumps in 2 µs with 10 µF and 45° of phase margin.Index Terms-Hysteretic current-mode control, design, analysis, dc-dc switching converter, stability, high bandwidth I. SWITCHED-INDUCTOR CONVERTERS Cellular phones, tablets, and other portable electronics today include on-demand functions like data conversion, telemetry, and others that require fast-responding and power-efficient supplies. Low-dropout (LDO) regulators are fast and compact, but not as efficient as their switchedinductor counterparts. Pulse-width-modulated (PWM) supplies are therefore popular, except they require several clock cycles to respond to load dumps. Luckily, hysteretic loops respond when their controlled variables surpass their window limits, so they react within one switching cycle [1].Unfortunately, understanding the nonlinear feedback dynamics of hysteretic converters is arduous. Phase-plot portraits [2], sliding-mode theory [3]-[5], state-space averaging [6]-[7], and circuit averaging [8]- [12] help, but the equations they generate are often abstract and difficult to relate to circuit operation, to inductor-current and outputvoltage ripples, response time, and others. This is why engineers ultimately over-size inductors or capacitors, and in so doing, counter their own miniaturization efforts.This paper analyses hysteretic current-mode buck dc-dc converters from the perspective of a circuit-design engineer. In this light, as Section II explains, the hysteretic current loop implements an oscillator, whose closed-loop gain and delay Section III describes and quantifies. Section IV later discusses how the oscillator block affects the feedback dynamics of the voltage loop. Section V then verifies the analysis and design strategy for maximum speed and Section VI draws relevant conclusions. II. DESIGN STRATEGYWith enough equivalent series resistance (ESR) in the output capacitor, hysteretic buck converters can be simple and widely stable. This is because ESRs save some of the phase inductors and capacitors lose with the poles they establish. Unfortunately, state-of-the-art systems cannot afford to accommodate the voltage these ESRs produce when responding to sudden load dumps. So, with little to no ESR, engineers resort to removing the influen...

show abstract

“…La aplicación del controlador de histéresis multifase en convertidores reductores también ha sido tratada en diversos artículos y publicaciones científicas [62]- [67]. Estos trabajos focalizan su atención en el balance de corriente y el funcionamiento entrelazado.…”

Section: Estado Del Arte Del Controlador De Histéresis Para El Conver...unclassified

Controlador de histéresis de bajo coste para convertidos buck síncrono multifase

Borrell Sanz

View full text Add to dashboard Cite

The multiphase synchronous buck converter is universally used today for powering low voltage, high current and high slew-rate loads, such as CPUs and other high performance digital ICs. This converter demands control techniques with high dynamical response in order to face large and fast load transients. In this regard, hysteretic regulators represent an excellent option due to their immediate reaction, unlimited duty cycle and outstanding capacity for handling large signal regimes. The main contributions of much published work in the field of multiphase hysteretic controllers are current sharing and phase interleaving. However, the author is not aware of any studies describing a control scheme that integrates the main control functions for powering such demanding loads: output voltage regulation, adaptive voltage positioning, current sharing and phase interleaving. Nor is there a design methodology based on the closed-loop output impedance. This design would optimize the output voltage transient response and, in this way, the entire voltage tolerance window of the processor would be exploited. Thus, this research work presents a novel hysteretic controller for a multi-phase synchronous buck converter supplying low voltage, high current and high slew-rate loads along with a design methodology based on closed-loop output impedance analysis. The single-phase hysteretic controller is the start point for this research work. Several authors have extensively treated the single-phase hysteretic controller. In this regard, a review of a low-cost single-phase control scheme is carried out first. The main feature of this controller is the lack of current sensing and processing circuitry in order to accomplish the adaptive voltage regulation. Then, the influence of variations of the inductor and output capacitor and the control parameters on the output impedance is studied. This has allowed for establishing a correspondence between each of the control parameters and the output filter components. The review finishes by implementing a synchronization system to achieve fixed switching frequency in steady state while maintaining the instantaneous reaction and optimal output-voltage response during transients. At this point, a novel low-cost hysteretic controller for multiphase synchronous buck converters is presented. Two design alternatives for the controller are proposed. The first uses an equivalent single-phase converter to design the control parameters. This approximation is valid as long as the deviations between the phases of the converter are within the usual limits (+/- 15 %). The second does the same considering the exact model of the converter, achieving resistive output impedance regardless of the differences that exist between the phases. Simulation and experimental results are reported in order to validate the features of the novel control scheme. From a practical point of view, the lack of current sensing and processing circuitry in the controller allow for a simple and low-cost implementation of the adaptive voltage positioning and current sharing with outstanding performance. The injection of an external synchronization signal has been proved to be a simple alternative in order to implement fixed switching frequency and phase interleaving operation. Finally, the proposed controller achieves similar characteristics to the high performance controllers intended for powering low voltage, high current and fast transient loads, but with the additional advantage of simplicity and low-cost circuit implementation. Actualmente, el convertidor buck síncrono multifase es universalmente utilizado para la alimentación de cargas dinámicas de baja tensión y elevada corriente como CPUs y otros circuitos integrados digitales de altas prestaciones. Este convertidor exige de técnicas de control con alta respuesta dinámica para hacer frente a los grandes y rápidos transitorios de carga a los que es sometido. A este respecto, los reguladores de histéresis representan una excelente opción debido a su reacción inmediata, ciclo de trabajo ilimitado y excepcional capacidad para manejar régimen de gran señal. Las principales aportaciones de la mayor parte de trabajos publicados en el campo de los controladores de histéresis multifase son distribución de corriente entre las fases y funcionamiento entrelazado. Sin embargo, el autor no tiene conocimiento de estudios que describan un esquema de control que integre las principales funciones de control para la alimentación de tales exigentes cargas: regulación de tensión de salida con posicionamiento adaptativo, distribución de corriente y funcionamiento entrelazado. Tampoco existe una metodología de diseño basada en la impedancia de salida de lazo cerrado. Este diseño optimiza la respuesta transitoria de la tensión de salida y, de este modo, se puede aprovechar toda la ventana de tolerancia del procesador. Por lo tanto, este trabajo de investigación presenta un novedoso controlador de histéresis para convertidor síncrono multifase destinado a alimentar cargas dinámicas de baja tensión y alta corriente, junto con una metodología de diseño basada en el análisis de la impedancia de salida de lazo cerrado. El controlador de la histéresis de una sola fase es el punto de partida de este trabajo de investigación. Varios autores han tratado ampliamente el controlador de histéresis de una sola fase. En este sentido, en primer lugar se lleva a cabo una revisión de un esquema de control de bajo coste de una sola fase. La característica principal de este controlador es la ausencia de circuitos de sensado y procesado de corriente para lograr la regulación de tensión adaptativa. El estudio de la influencia de las variaciones del inductor, condensador de salida y los parámetros de control y los componentes del filtro de salida. La revisión termina implementando un sistema de sincronización para lograr frecuencia fija de comunicación en estado estacionario, que mantiene la reacción instantánea y la respuesta transitoria óptima de la tensión de salida. Llegado a este punto, se presenta un controlador de histéresis de bajo coste para convertidores buck síncrono multifase. Se proponen dos alternativas de diseño para controlador. La primer a utiliza un equivalente de convertidor de una sola fase para diseñar los parámetros de control. Esta aproximación es válida siempre y cuando las desviaciones entre las fases del convertidor están dentro de los límites habituales (+/-15%). La segunda hace lo propio teniendo en cuenta el modelo exacto del convertidor, logrando impedancia de salida resistiva independientemente de las diferencias que existan entre las fases. Se presentan los resultados de simulación y experimentales con el fin de validar las características del esquema de control propuesto. Desde un punto de vista práctico, la ausencia de circuitos de sensado y procesado de corriente en el controlador permiten una implementación sencilla y de bajo coste para las funciones de regulación de tensión con posicionamiento adaptativo de reparto de corriente con buen rendimiento. La inyección de una señal de sincronización externa demuestra ser una alternativa simple a fin de obtener frecuencia fija de conmutación y funcionamiento entrelazado de las fases. Finalmente, el controlador propuesto alcanza características similares alos controladores destinados a la alimentación de cargas de baja tensión y alta dinámica con la ventaja adicional de la simplicidad y el bajo coste de implementación.

show abstract

A Hysteretic Control Method for Multiphase Voltage Regulator

Cited by 41 publications

References 9 publications

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

Stability analysis & design of hysteretic current-mode switched-inductor buck DC-DC converters

Controlador de histéresis de bajo coste para convertidos buck síncrono multifase

Contact Info

Product

Resources

About

A Hysteretic Control Method for Multiphase Voltage Regulator

Cited by 41 publications

References 9 publications

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

An Effect of Output Capacitor ESL on Hysteretic PLL Controlled Multiphase Buck Converter

Stability analysis &amp; design of hysteretic current-mode switched-inductor buck DC-DC converters

Controlador de histéresis de bajo coste para convertidos buck síncrono multifase

Contact Info

Product

Resources

About

Stability analysis & design of hysteretic current-mode switched-inductor buck DC-DC converters