Unlike PWM-controlled converters, where energy flow is controlled by the duty cycle of theprimary switch (or switches), in a resonant half bridge the duty cycle is fixed and energy flowis controlled by its switching frequency. This impacts on the way current limitation can berealized. While in PWM-controlled converters energy flow can be limited simply byterminating switch conduction beforehand when the sensed current exceeds a presetthreshold (this is commonly known as cycle-by-cycle limitation), in a resonant half bridge theswitching frequency