ST’s family of resonant controllers includes primary controllers for double-ended (half-bridge) topologies, designed to provide high efficiency under any load conditions, as well as high noise immunity (zero voltage switching operation).

The L6598, the 1st generation of ST’s resonant controllers, implements an HV half bridge driver that directly drives two power MOSFETs and has a dedicated timing section to set soft start duration and minimum operating frequency.

The L6599 and L6599A, ST’s second and third generation of resonant controllers, offer increased operating frequency (up to 500 kHz), additional features such as burst-mode operation to reduce the consumption at light load operation, a dedicated pin for direct connection with the PFC controller, and improved protection features, such as two-level OCP (frequency-shift and latched shutdown), brownout protection and latched disable input.

These controllers are widely used in LCD TVs, all-in-one PCs, high-power LED lighting and AC-DC adapters (>90 W).