A 93.9% Peak Efficiency 3V-to-40V-Input GaN-based DC-DC Converter with Unified Reliability and Efficiency Adaptive Control

A Gallium Nitride (GaN)-based DC-DC converter has received large research attention for automotive applications since it can support a wide range of input voltage, e.g., from 3V to 40V, to cover car battery voltage fluctuations at higher efficiency [1]–[3]. However, the reliability of GaN switches is a serious concern, especially in the harsh environment commonly found in such applications. The intrinsic failure mechanisms, where elevated junction temperatures ($T_j$) and excessive gate-to-source ($V_{gs}$) and drain-to-source voltage ($V_ds$) cause the degradations in the on-state resistance ($R_{0∩}$) and threshold voltage ($V_{th}) of a GaN device [4]. Recent works have proposed various reliability management techniques [5]–[15]. However they are still limited in the multiple ways. First of all, all of the prior works solely focus on reliability but it is critical to manage both reliability and efficiency. Also, some of the works employed an open-loop control, whose effectiveness is lower than the closed-loop control [9]–[15]. Also, none of the works monitor all four critical parameters,$R_0$,$V_{th}$,$T_j$, and inductor current ($I_s$), nor utilize all two critical control knobs, switching frequency ($F_{sw}$) and gate drive swing ($V_{drv}$), to maximize reliability and efficiency via a closed-loop control.