A 48V-to-1V Buck-Assisted Active-Clamp Forward Converter with Reduced Voltage Stress for Datacenter Applications

A Resonant One-Step 325 V to 3.3–10 V DC–DC Converter With Integrated Power Stage Benefiting From High-Voltage Loss-Reduction Techniques

“…Hence, they are not well suitable to supply microcontrollers, sensors, and so on. To increase the efficiency and to reduce the size at high input voltages and low output power, approaches, including multi-level converters [6]- [9], fly-buck converters [9], [10], and soft-switching converters [11]- [14], have been published, but their complexity is high and they still show a low light-load efficiency. In addition, although these converters allow for higher input voltages, their capability of handling input voltages of up to 400 V efficiently at a compact size is limited.…”

“…This limits either the maximum input voltage or the level of integration. V overshoot can be reduced with passive or active voltage clamps [13], [14], [20]- [24], which increases the converter complexity [Fig. 2 (left)].…”

“…Soft-switching concepts, such as active-clamp flyback (ACF) [Fig. 2 (left)] [13], [14], [20]- [24], or operating in discontinuous conduction mode, as suggested in [21], reduce the losses at turn on, but increase the complexity of the power stage and the control, and the losses at the turn off remain high for most approaches. Furthermore, soft switching in ACF converters requires a minimum negative inductor current, which reduces the light-load efficiency.…”