Fixed-frequency adaptive-on-time boost converter with fast transient response and light load efficiency enhancement by auto-frequency-hopping

An integrated fixed-frequency adaptive-on-time DC-DC converter with fast transient response and high light load efficiency is presented. To achieve fixed frequency at continuous conduction mode, the on-time is adaptively controlled to force the switching frequency tracks the reference frequency with less than +/-0.5% error within the whole operating range. To enhance the light load efficiency as well as reduce EMI noise problem, the on-time is adjusted to maintain the switching frequency hops between 1MHz and 1MHz/N where N = 2ⁱ and i = 1 to 5 according to the loads without load current sensor.