Jimin Oh

A Novel Fabrication of TDMOSFETs Using Two Steps Trench Etching and Twice Self-Alignment Technique

ABSTRACT A new fabrication method employing two-step trench etching and twice self-alignment technique was developed to obtain high cell density trench power MOSFETs by using only three mask steps. This method was implemented to increase cell density, to decrease on-resistance and to improve leakage current characteristics. The trench DMOSFETs with 1.6 μm cell pitch and 140 Mcell/in2 cell density were fabricated. The specific on-resistance of the device is about 0.48 mΩ˖cm2 with the breakdown voltage of 43 V.

High performance of PMSM driver IC integrated sensorless and current sensing circuits

This work proposes high performance of permanent-magnet synchronous motor (PMSM) driver IC integrated with position sensorless scheme and current sensing circuits. The position sensorless scheme is adapted with digital sliding mode observer (SMO) method that has high robust characteristics of motor parameter variations. For current sensing circuits, 10-bit successive approximation (SAR) analog-to-digital converters (ADC) and various (1~16) gain amplifiers are implemented in the fabricated IC. The proposed PMSM driver IC is fabricated with 0.18um BCD process. Compared with the commercial module, with the accurate SMO scheme, a speed error is reduced to 0.7% at 3000rpm and a system efficiency is increased to 1.9 % at 3000rpm, 5N·m. The high precision position estimating driver IC is achieved without any position/current sensors.