Design Support


With GaN devices, power electronics designers are now able to push the switching frequency of their designs to levels not possible with today ’s Si MOSFETs. Higher switching frequencies reduce the size of passive components in the system and in turn increase the overall power density. To make these solutions robust, protection against overcurrent events is needed. Traditional approaches using current sense transformer, shunt resistors, or de-saturation detection circuits remain ineffective due to slow response time. These techniques may also adversely affect the system performance by adding parasitic inductances and resistances in the power loop that may require slowing down GaN switching speed or cause additional power losses in the system. To solve this challenge, TI’s LMG341X family of GaN power stages provide an integrated OCP function. This high-speed feature can turn off the GaN FET in less than 100-ns in an overcurrent or short-circuit event. This application note explains the importance of this feature as well as “latched ” or “cycle-by-cycle ” modes of operation.