A Current-Mode DC–DC Buck Converter with Efficiency-Optimized Frequency Control and Reconfigurable Compensation

Liu, Jiaming; Wang, Pai-Yi; Kuo, Tai‐Haur

doi:10.1109/tpel.2011.2162079

Cited by 51 publications

(19 citation statements)

References 15 publications

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“…Gate drive voltage scaling technique to lower gate drive losses is reported in [3,4]. Many recent works have reported combination of the above techniques to improve efficiency over the entire range of a converter [5,6]. On the other hand, buck regulators for lower power portable applications if operated in DCM requires small inductor, even at low switching frequency.…”

Section: Introductionmentioning

confidence: 99%

High efficiency DCM buck converter with dynamic logic based adaptive switch-time control

Manohar

Balsara

2015

Analog Integr Circ Sig Process

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This paper presents a dynamic logic based adaptive switch-time control circuit (DASTC) for fast control to minimize body diode conduction losses and dead-time of a buck regulator operating in discontinuous conduction mode. Dead-time is an important metric for improving efficiency of low voltage converters. DASTC provides instant sensing and feedback based on the load to minimize dead-time significantly compared to prior-art and scales low side power switch pulse width adaptively across load currents, just enough to discharge the stored inductor energy fully. Furthermore, the converter has inherent pulse skipping mode to lower the switching frequency at light loads to enhance light load efficiency. The proposed 1.5 V buck regulator was fabricated in 0.35 lm CMOS process with an input voltage range of 1.8-3 V and load current range of 1-200 mA. Measurement results demonstrate a peak power efficiency of 94.6 % and a high overall power efficiency ( [*89 %) for load currents greater than 5 mA for V IN = 1.8 V. The proposed scheme achieves 49 (*5 ns) better dead-time and 4-5.5 % better power efficiency compared to prior-art over the load current range.

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Section: Introductionmentioning

confidence: 99%

High efficiency DCM buck converter with dynamic logic based adaptive switch-time control

Manohar

Balsara

2015

Analog Integr Circ Sig Process

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“…Linear regulators or low-dropout (LDO) regulators are compact and fast but offer poor efficiency when the difference between input and output voltage is considerable [1][2]. Compared to buck converters with high-quality off-chip or package-integrated inductors [3][4] providing high efficiency across a wide output voltage range, on-chip buck converters [5][6] still suffer low efficiency and low current density due to low-quality and bulky inductors. Fully-integrated switchedcapacitor converters [7][8][9][10][11][12][13][14][15] offer high efficiencies at integer step-down conversion ratios, and high current density could be achieved using high-density on-chip capacitors [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Fully-integrated switched-capacitor voltage regulator with on-chip current-sensing and workload optimization in 32nm SOI CMOS

Mandal

Sathe

et al. 2015

2015 IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED)

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Efficient, stable, and fast power delivery against fluctuating workloads have become a critical concern for applications from battery-powered devices to high-performance servers. With high density on-chip capacitors, fully-integrated switched-capacitor (SC) voltage converters provide high efficiency down-conversion from a battery or off-chip voltage regulation modules. However, maintaining such efficiency with minimal supply noise across a wide range of fluctuating load currents remains challenging. In this paper, we propose an onchip current sensing technique to dynamically modulate both switching frequency and switch widths of SC voltage converters, enhancing fast transient response and higher efficiency across a wide range of load currents. In conjunction with SC converters, we employ a low-dropout regulator (LDO) driven by a push-pull operational transconductance amplifier (OTA), whose current is mirrored and sensed with minimal power and efficiency overhead. The sensed load current directly controls the frequency and width of SC converters through a voltagecontrolled oscillator (VCO) and a time-to-digital converter, respectively. In 32nm SOI CMOS, the proposed voltage regulator maintains 77-82% efficiency at 0.95V output voltage with less than 20mV steady-state ripple across 10X load current range of 100mA-1A and 33mV droop voltage for a 80mA/ns load transition, while providing a projected current density of 6W/mm 2 .

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“…Current-mode control is frequently used in dc-dc buck converters [1]- [6] due to advantages such as better line transient response and inherent cycle-by-cycle current protection, as compared to voltage-mode control [1]. Type-II compensators are usually applied to current-mode buck converters for obtaining high loop gain to reduce the steady-state error and maintaining loop stability.…”

Section: Introductionmentioning

confidence: 99%

An undershoot/overshoot-suppressed current-mode buck converter with voltage-setting control for type-II compensator

Wang

Huang

Fang

et al. 2015

2015 IEEE Asian Solid-State Circuits Conference (A-Sscc)

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Current-mode control is frequently used in dc-dc buck converters. Many current-mode buck converters apply type-II compensators for obtaining high loop gain to reduce the steadystate error and maintaining the loop stability with restricted bandwidth. However, when large load-current transients occur, significant transient undershoot/overshoot is generated due to the restricted loop bandwidth. In response, a type-II compensator with the proposed voltage-setting control (VSC) is presented in this paper. By simply setting the voltage of the compensation capacitor and the input voltage of the compensator, the proposed VSC, which is activated by a transient detector, greatly suppresses the transient undershoot and overshoot. Implemented , this work occupies 0.91mm 2 including pads, and features a peak efficiency of 96.3%. With the proposed method, the maximum undershoot and overshoot are respectively suppressed from 150mV to 58mV and 92mV to 62mV for ± 1A load current steps.

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A Current-Mode DC–DC Buck Converter with Efficiency-Optimized Frequency Control and Reconfigurable Compensation

Cited by 51 publications

References 15 publications

High efficiency DCM buck converter with dynamic logic based adaptive switch-time control

High efficiency DCM buck converter with dynamic logic based adaptive switch-time control

Fully-integrated switched-capacitor voltage regulator with on-chip current-sensing and workload optimization in 32nm SOI CMOS

An undershoot/overshoot-suppressed current-mode buck converter with voltage-setting control for type-II compensator

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