홍성완 교수

This paper presents a novel capacitor-less low-dropout regulator (LDO) for mobile applications. The proposed capacitor-less LDO utilizes multiple feedback loops to satisfy several design challenges for some mobile applications which were not considered in the previous capacitor-less LDOs. The proposed LDO has a wide bandwidth of 3.03 MHz at a load current of 150 mA with a bias current of 40 μA, and the best line and load regulations of 0.0024%/V and 0.0000417%/mA, respectively, which are improve

A dual-path step-down converter (DPDC) is presented for achieving high power efficiency in the mobile power management ICs (PMICs). Adopting a hybrid structure using one inductor and one flying capacitor, the proposed DPDC supplies a load current via two parallel paths, relieved an intrinsic problem of the conventional buck converter (CBC) topology, which is a significant power loss from a large DCR of the inductor (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3

This article proposes a new boost converter topology called dual-path step-up dc-dc converter (DPUC). Unlike the conventional boost converter (CBC), the DPUC has a hybrid structure using one inductor and one flying capacitor to make dual current delivery paths. This allows continuous current delivering to the output, reducing both the dc level of the inductor current and the output voltage ripple. Therefore, the DPUC has higher efficiency and smaller output voltage ripple than those of the CBC.

This paper presents a double pile-up resonance energy harvesting circuit that efficiently and simultaneously extracts energy from a piezoelectric transducer (PZT) and a thermoelectric generator. The proposed harvester operates in a double pile-up mode (DPM) to efficiently extract energy from PZT with the enhanced damping force, resulting in a 1452% improvement in power extraction, which is the best performance among the state-of-the-art works. The harvester also operates in a boost converter mod

Energy harvesting is one of the key technologies used to realize self-sustaining systems such as wireless sensor networks and health-care devices. Much research on circuit design has been conducted to extract as much energy as possible from transducers, such as the thermoelectric generator (TEG) and the piezoelectric transducer (PZT). Specifically, the energy in a PZT could be extracted more efficiently by utilizing resonance as [1] and [2] demonstrated. However, the maximum output voltage swing

While the demand for micro-energy harvesters (μEHs) is increasing (for seamless energy source in applications such as wireless sensor node), two major problems still obstruct versatile use of them. The first problem is the self-startup capability. Because many wireless sensor nodes are likely to be located where human-maintenance is difficult, starting them up manually can be as difficult as replacing the battery. Its realization has been difficult because μEHs must be able to turn itself on wit

DC-DC boost converters are widely used to increase the supply voltage in various applications, including LED drivers, energy harvesting, etc. [1-5]. The conventional boost converter (CBC) is shown in Fig. 27.5.1, where the switches S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> and S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> are turned on and off alternately at φ <sub xmlns:mml=

This letter proposes a loop-free autocalibration technique for self-balancing of flying capacitors in a three-level dc-dc buck converter. The proposed converter utilizes a dual-path power stage with balancing switches that adaptively short flying capacitors at de-energizing phases. Thus, the dual-path three-level converter ensures that flying capacitor voltages are self-balanced at half the input voltage without using additional feedback calibration loops, leading to robust operation and competi

In this letter, a noninverting buck-boost converter with state-based current control is proposed for Li-ion battery management. Unlike conventional multimode control in buck-boost converters, our control scheme utilizes a state controller with a single-level error current and a state checking clock to define the operation mode at every cycle. The state-based buck-boost converter enables seamless mode transition and stable output regulation with fixed interleaving patterns even when input and out

A DC-DC converter, which tracks minimum power loss under various conditions, is presented in this paper. With this DC-DC converter, a new approach for optimum efficiency, which implements theoretical equations intactly at the circuit level, was adopted. This approach has high reliability against process variation. The concept of lossless soft-switching was also adopted in discontinuous-conduction-mode (DCM) operation. The proposed DC-DC converter has a maximum power efficiency of 91% at the swit

A robust multioutput self-regulated rectifier without any switching circuitry is proposed in this letter for wirelessly powered biomedical devices, especially for neural stimulators. The proposed system utilizes the series and parallel resonant configuration for low- and high-side outputs, respectively, by using only one resonant capacitor. The proposed system provides dual high voltages of ±14 V for neuro stimulator and low voltage of 2.1 V for operating systems such as read-out and digital cir

This paper presents a pseudo single-stage (PSS) amplifier with an adaptively varied medium impedance node to achieve an ultra-high slew rate (SR) and at the same time stable operation in a wide capacitive load range. Owing to the characteristics of the proposed technique, this amplifier achieves a 1.1-to-8.67 V/μs slew rate and a 0.01-to-1.66 MHz unity gain frequency over a 0.1-to-15 nF capacitive load (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xli

As more features have been added to mobile devices, it has become necessary to integrate more DC-DC converters into the power-management IC. Consequently, there is a growing need for an area-efficient and simple controller design for DC-DC converters. A simple hysteretic control without any additional component for compensation is a very attractive solution because it is not only cost-effective, but also immediately responds to load change. However, a conventional current-mode hysteretic control

This article proposes a current-mode (CM) receiver for a wireless power transfer (WPT) application that receives both power and data from the transceiver. The proposed CM receiver decreases the voltage stress applied to transistors to store a larger amount of power in its LC tank, and this charges the battery without any residual power. Accordingly, the receiver achieves the highest maximum receiver efficiency of 92.6% among the state-of-the-art CM receivers at an input power of 10.89 mW. The pr