The L6699 is a double-ended controller specific to series-resonant half bridge topology. Both LLC and LCC configurations are supported. It provides symmetrical complementary duty cycle: the high-side switch and the low-side switch are driven ON/OFF 180° out-of-phase for exactly the same time. Output voltage regulation is obtained by modulating the operating frequency. The deadtime inserted between the turn-off of one switch and the turn-on of the other one is automatically adjusted to best fit the transition times of the half bridge midpoint. To drive the high-side switch with the bootstrap approach, the IC incorporates a high voltage floating structure able to withstand more than 600 V with a synchronous-driven high voltage DMOS that replaces the external fast-recovery bootstrap diode.
Features:
Symmetrical duty cycle, variable frequency control of resonant half bridge
Self-adjusting adaptive deadtime
High-accuracy oscillator
2-level OCP: frequency-shift and immediate shutdown
Interface with PFC controller
Anti-capacitive-mode protection
Burst-mode operation at light load
Input for brownout protection or power-on/off sequencing
“Safe-start” procedure prevents hard switching at startup
600 V rail compatible high-side gate driver with integrated bootstrap diode and high dv/dt immunity
-300/800 mA high-side and low-side gate drivers with UVLO pull-down