Power Management ICs

In order to make a multi-functional and high-performance system, power management IC (PMIC) has emerged as a very important role for efficiently managing battery resources

Input-to-output voltage regulator, such as low dropout regulator (LDO) and DC-DC converter, is an essential circuit of a PMIC. In accordance with the increase in the mobile application markets, recent technology is toward minimizing or eliminating discrete elements such as an inductor or capacitor used in the regulator. Since switching frequency needs to be increased to minimize discrete elements, a DC-DC converter is required not only to maximize the power transfer efficiency but also to minimize the switching loss. In the case of an LDO, it is required to improve power supply rejection ratio (PSRR) and transient response to minimize the output capacitor, so that it can be implemented in a single chip without an external capacitor attached.

Energy Harvesting in Large Scale

As the costs of fossil fuels and their environmental concerns rise, the demand for innovation in renewable energy grows. In conventional photovoltaic (PV) systems using central or string inverters, each PV module array is connected to an inverter that uses passive components such as large capacitors and inductors. Mismatch and partial shading problems among PV modules connected in series are the primary sources of the power loss. In order to mitigate these problems, a maximum power point tracking (MPPT) controller can be embedded into an inverter. To further increase the energy that can be harvested, distributed PV systems with an MPPT for each PV module have been widely researched.

In our lab, we have developed MPPT algorithms that detect the MPP quickly without fluctuation or an additional ad hoc parameter, which allows for superior performance compared to others in the tracking and the power loss not only under the steady state (normal operation) but also under the dynamic state (tracking operation).

Motion Gesture Sensor

Now a days, smartphone is essential for our daily life. Touch screen has been a main human-machine interface (HMI) in smartphone devices. Since smartphones operate under various conditions, the demands for non touch-based HMIs are increasing. Motion gesture sensor (MGS) detects motions of an object without touching a panel. There are several different types of MGS: vision based, proximity based, and so on. Vision-based MGS, like a camera, can detect many motions but consumes too much power for being used in mobile devices. Proximity-based MGSs can be small size and low power, but have limited motion detection. In our lab, we have researched the optical path of IR light and developed a single-chip MGS for mobile devices.

Finger Navigator

The development of HMI is continuously pursuing an user-friendly interface and simplification of system. The traditional keyboard-input has been replaced gradually. The touch panel evolves from single-touch to multi-touch interface. The body sense technology even gets rid of restriction of input device. This is the newest and most popular research area. The most important part of this might be manipulation by using hand. We devote our efforts to propose a system which can detect fingertips accurately and steadily in 2D.