A Hybrid Structure Dual-Path Step-Down Converter With 96.2% Peak Efficiency Using 250-m \Omega Large-DCR Inductor

A dual-path step-down converter (DPDC) is presented for achieving high power efficiency in the mobile power management ICs (PMICs). Adopting a hybrid structure using one inductor and one flying capacitor, the proposed DPDC supplies a load current via two parallel paths, relieved an intrinsic problem of the conventional buck converter (CBC) topology, which is a significant power loss from a large DCR of the inductor ( {R}_{\mathrm {DCR}} ). Therefore, DPDC achieves a high power efficiency and thus also reduces the heating problem, which is another critical issue in the mobile set. Moreover, DPDC can shrink the volume of the PMIC set with a low manufacturing cost by alleviating an {R}_{\mathrm {DCR}} specification of the inductor. In this paper, although a 250 \text{m}\Omega of large {R}_{\mathrm {DCR}} inductor is used for our measurements, a 96.2% of peak efficiency was achieved and the power loss of total parasitic resistances can be reduced to up to 30% of that of CBC. Moreover, according to our measurement plots, it is verified that DPDC achieves the efficiency notably higher not only in a wide load current ( I_{\mathrm {LOAD}} ) range but also in a wide conversion ratio ( V_{\mathrm {OUT}}/V_{\mathrm {IN}} ) range, compared to CBC.