부산대학교 도서관

This article proposes an inverting buck-boost drive (IBBD) gallium nitride (GaN) driver, which directly drives depletion-mode GaN (D-GaN) metal–insulator–semiconductor high-electron-mobility transistor (MIS-HEMT). In the proposed driver fabricated with a 0.5- $\mu \text{m}$ CMOS process, the $V_{\mathrm {th}}$ tracking technique can reduce switching loss and minimize the leakage current of D-GaN MIS-HEMT to sub-1 $\mu \text{A}$ . To suppress the electromagnetic interference (EMI) caused by the ringing voltage at drain of the GaN switch when reducing from 22 to 1.9 V, a Miller plateau (MP) detector and an EMI suppression frequency controller (ESFC) are also applied. With the slew rate (SR) control and fast-level shifter, the maximum switching frequency can reach up to 20 MHz, and $dV_{\mathrm {DS}}$ /dt can be regulated at 120 V/ns. In addition, the power saving mode of IBB converter and accurate ultralow power (ULP) under voltage lockout (UVLO) are proposed to reduce the quiescent current to 580 nA during standby mode, thereby enhances light load efficiency. The peak efficiency is as high as 95.8% and chip areas are 5.1 and 6.6 mm2.