GaN同步Buck变换器的实时预测死区时间优化集成驱动器

With the superior figure of merit (FOM), gallium nitride high electron mobility transistors (GaN HEMTs) currently play a critical role in the switched-mode power supplies (SMPSs) application with the megahertz switching frequency, high-power density, and efficiency. The frequency-dependent dead-time losses during the reverse conduction, however, significantly degrade the conversion efficiency. Reverse conduction can also increase the risk of the bootstrap (BST) voltage overcharge. This article proposes a dead-time optimization technique (DOT) based on predictive V_ SW detection that can effectively eliminate reverse conduction. Unlike conventional methods that require multiple cycles to determine the optimal dead time, the proposed DOT can achieve the optimal dead time in real-time across a wide range of V_ IN (24–48 V) and load current (0.1–6 A). A test chip was fabricated in a 0.18~ m Bipolar-CMOS-DMOS (BCD) process. The experimental results demonstrate that the reverse conduction has been eliminated through zero voltage switching (ZVS) or partial ZVS with a negligible switching node voltage. A 4.3% efficiency improvement in 48–5 V buck converter ( I_ L =6 A) is, furthermore, achieved with the proposed DOT.