A buck converter with adaptive on-time PFM control and adjustable output voltage

Nam, Hojung; Ahn, Youngkook; Roh, Jeongjin

doi:10.1007/s10470-011-9802-7

Cited by 16 publications

(9 citation statements)

References 14 publications

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“…Constant on-time control [21][22][23] can also be implemented in PFM within a small area under light-load conditions, but the problem of switching frequency variability still remains. Therefore, adaptive on-time control [24][25][26][27][28] has been utilized to improve EMI problems due to switching frequency variation. It alleviates the problem of switching frequency variability by using a simple sensing circuit, which requires additional area and power consumption.…”

Section: Introductionmentioning

confidence: 99%

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A PWM/PFM Dual-Mode DC-DC Buck Converter with Load-Dependent Efficiency-Controllable Scheme for Multi-Purpose IoT Applications

Kim

2021

Energies

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This paper presents a dual-mode DC-DC buck converter including a load-dependent, efficiency-controllable scheme to support multi-purpose IoT applications. For light-load applications, a selectable adaptive on-time pulse frequency modulation (PFM) control is proposed to achieve optimum power efficiency by selecting the optimum switching frequency according to the load current, thereby reducing unnecessary switching losses. When the inductor peak current value or converter output voltage ripple are considered in some applications, its on-time can be adjusted further. In heavy-load applications, a conventional pulse width modulation (PWM) control scheme is adopted, and its gate driver is structured to reduce dynamic current, preventing the current from shooting through the power switch. A proposed dual-mode buck converter prototype is fabricated in a 180 nm CMOS process, achieving its measured maximum efficiency of 95.7% and power density of 0.83 W/mm2.

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Section: Introductionmentioning

confidence: 99%

“…Finally, the conclusions are drawn in Section 4. Figure 1 presents two conventional DC-DC buck converter control methods for the adaptive on-time controlled PFM converter [24,35] and the voltage-mode PWM DC-DC buck converter [36][37][38]. In Figure 1a, the PFM buck converter operates with the adaptive on-time control scheme.…”

Section: Introductionmentioning

confidence: 99%

A PWM/PFM Dual-Mode DC-DC Buck Converter with Load-Dependent Efficiency-Controllable Scheme for Multi-Purpose IoT Applications

Kim

2021

Energies

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“…How to reduce the design complexity, reduce the cost, improve the conversion efficiency and speed up the transient response of the power supply system are the most basic and significant issues now [1,2,3,4,5]. As one of the power sources, DC-DC switching power supply is widely used in the modern electronic product market due to its high integration, high efficiency, small size and strong anti-interference ability [6,7]. The voltage mode control has simple structure and mechanism, which is easy to model for analysis and simulation.…”

Section: Introductionmentioning

confidence: 99%

An IAOT controlled current-mode buck converter with RC-based inductor current sensor

Jiang

Chai

Yang

et al. 2020

IEICE Electron. Express

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An improved adaptive-on-time (IAOT) controlled current mode buck converter with RC-based current-sensing circuit and internal softstart property is presented in this paper. First, the inductor current is sensed by a resistor-capacitor (RC) network, which can fully sense the trend of inductor current with high accuracy. Second, an IAOT control circuit is used to realize the on-time of the power switch adaptively changing with the operation conditions. In addition, the overshoot (undershoot) voltages are reduced by making T ON adaptively shorter (longer) during the unloading (loading) transient due to the IAOT control. Third, soft start operation protects the circuit from large in-rush current during startup of the converter. Fourth, the proposed buck converter was implemented with standard 0.18-µm CMOS process. Simulation outcomes have shown an input voltage of 5 V, when the output voltage is ranging from 1.2 V to 3.6 V, with a maximum conversion efficiency of 98% (heavy loads) and 94% (light loads), making the buck converter quite useful in power management ICs.

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“…Switching regulators are widely used in portable electronic devices because of their high efficiency [1][2][3][4][5][6]. Traditional methods for switching regulators include fixed frequency control, such as voltage mode pulse width modulation (PWM) control and current mode PWM control [7][8][9], and variable frequency control, such as constant on-or off-time control [10] and ripple control [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Frequency compensation circuit for adaptive on‐time control buck regulator

Shi

Ling-yan

2014

IET Power Electronics

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A novel frequency compensation circuit for adaptive on-time control buck regulator is presented in this study, which mainly applied to provide power supply for double data rate synchronous dynamic random access memory system. Typical ripple control regulator possesses the advantage of fast transient response and unconditional stability. However, it suffers significant steady-state switching frequency variation when the input voltage and output voltage are varied. The on-time is directly proportional to the output voltage and inversely proportional to the input voltage so that the regulator can dynamically adjust the turn-on time of power switches according to the changes of input voltage and output voltage in steady-state operation by adaptive on-time control. Finally, an approximately fixed switching frequency is achieved. However, the variation of the switching frequency with load current still exists. Through the implementation of the frequency compensation circuit, the switching frequency variation caused by the load current variation can be effectively reduced in order to obtaining a more fixed switching frequency. The adaptive on-time control regulator with frequency compensation has been successfully fabricated with 0.35 µm 30 V complementary double-diffused metal oxide semiconductor process and full chip test results are provided to verify the proposed method in this study.

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A buck converter with adaptive on-time PFM control and adjustable output voltage

Cited by 16 publications

References 14 publications

A PWM/PFM Dual-Mode DC-DC Buck Converter with Load-Dependent Efficiency-Controllable Scheme for Multi-Purpose IoT Applications

A PWM/PFM Dual-Mode DC-DC Buck Converter with Load-Dependent Efficiency-Controllable Scheme for Multi-Purpose IoT Applications

An IAOT controlled current-mode buck converter with RC-based inductor current sensor

Frequency compensation circuit for adaptive on‐time control buck regulator

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