In certain embodiments, driver circuitry generates drive signals to drive driven circuitry to transition between first and second states. The driver circuitry has a first-to-second driver circuit that generates a first drive signal to drive the driven circuitry to transition from the first state to the second state and a second-to-first driver circuit that generates a second drive signal to drive the driven circuitry to transition from the second state to the first state. The driver circuitry includes two complementary triggered current pulse generators (described in U.S. Pat. No. 10,554,206) that combine to efficiently provide switch drive for a FET or other reactive load. The triggered drive has fast edges for low switching losses. In certain embodiments, the low power triggered drive circuitry can respond to a slowly changing feedback signal to switch a FET so as to regulate a power converter output.