Concept — ZVS Dead Time

In soft-switching topologies (LLC, Phase-Shifted Full-Bridge), the minimum dead time required to discharge the half-bridge output capacitance.

Formula

$t_{dead,min}=\frac{2\cdot Q_{oss}(V_{in})}{I_{magnetizing}}$

where Q_oss(V_in) is the output charge at the input voltage (see charge-conservation-qv).

Significance

Dead time too short → incomplete discharge → loss of ZVS, hard-switching loss; too long → circulating-current loss. The extracted non-linear C_ds/C_gd (see non-linear-capacitance-extraction) provides accurate Q_oss(V), giving the dead-time design a solid basis.

Related

• power-semiconductor-modeling
• power-mosfet, gan-hemt