A 2-MHz Wide-Input Hybrid Resonant Converter With Ultracompact Planar Coupled Inductor for Low-Power Integrated On-Chip Applications

A trend for low-power conversion system is to integrate every component to a single chip. Magnetic component has been the key to determine the power density of the integrated switching power converter. In this paper, a hybrid resonant buck-type converter with an ultracompact custom-designed coupled inductor is presented for low-power integrated on-chip applications. This converter achieves zero-voltage switching for the high-side switch and near zero-voltage zero-current switching for low-side and auxiliary switches. The soft-switching condition allows the circuit operating at high switching frequencies. An ultracompact planar coupled inductor with a dimension of 5.25 mm × 1.95 mm × 3.86 mm is designed and customized for future integrated on-chip applications. The high-power density of this magnetics component is achieved by high switching frequency and optimized printed circuit board (PCB) windings design. A hardware prototype with 24 to 60-V input and 3.3 to 5-V, 3-A output operating at 2-3 MHz is presented to verify the circuit operation. The prototype achieves a peak efficiency of 90.7% using silicon devices at 2-MHz switching frequency.