Adaptive Dead Time Control Strategy for ClosedLoop TCM GaN-Based Buck Converters

Gallium nitride (GaN) offers the advantages of high switching speeds and low on-resistance, which makes it suitable for extensive use in high-frequency applications requiring high power density and high efficiency. GaN-based high-frequency DC-DC buck converters typically employ the triangular current mode (TCM) to realize zero-voltage switching (ZVS) and reduce the inductor size. However, as the switching frequency increases, the effect of the dead time becomes greater. In addition, the ZVS of a device depends on the output power, which makes the design of dead time complex. Traditionally, the design of dead time is based on the worst condition; thus, the dead time is too long in the normal condition; this increases the duty loss and reduces the overall performance dramatically. To reduce the dead time loss in GaNbased TCM buck converters, an adaptive dead time control strategy is proposed in this paper to optimize the dead time in the entire power range. The experimental results demonstrate that adaptive dead time control can improve the overall efficiency compared with fixed dead time control, and the total loss was reduced by
$9.2{{\% }}$
at 200 W.