Hybrid buck converter optimization and comparison for smart phone integrated battery chargers

A 12V-to-1V switched-capacitor-assisted hybrid converter with dual-path charge conduction and zero-voltage switching

“…The possibility of employing lowvoltage transistors as the high-current power switches at the output for the proposed topology can also effectively reduce the switching loss and save the chip area. Apart from that, it also retains the advantage of full-range step-down VCR as the buck converter by grounding the inductor terminal in the two-phase operations, resolving the VCR limitation when compared with [5,6,7,8]. Finally, the employment of zerovoltage-switching (ZVS) [16,17,18,19,20] in the lightload condition can effectively alleviate the hard switching loss and body-diode conduction loss of the HV power transistors, which further improves the light-load efficiency.…”

“…This issue can negatively impact the conversion efficiency, especially under a heavy loading current. To overcome the hard-tradeoff between the conversion efficiency and the size of the power components, different types of switchedcapacitor (SC)-inductor hybrid converter topologies [2,3,4,5,6,7,8,9,10] have been proposed, targeting on reducing the inductor DCR loss through lowering the steady-state inductor DC current (IL,DC). In [2,3,4], the multi-branch architectures using multiple inductors (e.g., double-stepdown (DSD) topology) feature equal current flow in each branch, realizing a reduced total DCR loss due to the quadratic correlation between the inductor current and the power loss.…”

“…However, increasing the number of the inductor can inevitably raise the system volume and cost. Although the topologies reported in [5,6,7,8] can achieve IL,DC reduction without using additional inductors, they suffer from a limited voltage conversion ratio (VCR) range from 3:1 to 1:1, and therefore cannot fulfill the high step-down VCR scenarios, e.g., 12:1. The SC hybrid dual-path (DP) topologies presented in [9,10] realize an extended VCR range together with IL,DC reduction, which unfortunately degrades as VCR increases, indicating their incompatibility for high step-down application [11,12,13,14,15] (i.e., the DCR loss can still dominate the efficiency under a high VCR).…”

A multi-path switched-capacitor-inductor hybrid DC-DC converter with reduced inductor loss and extended voltage conversion range

“…However, these DP topologies suffer from a restricted voltage conversion ratio (VCR) of 1/2 to 1 due to the constraints on inductor charging and discharging voltages, limiting their application of converting a 5-V bus voltage to a 1.8-V load supply. Although this issue can be resolved by adding an extra power switch and one more switching phase, as discussed in [20], the effectiveness of the inductor current reduction degrades with enlarging the step-down VCR, resulting in a reported in (a) [1] and (b) [20].…”

Control of a DC-DC Buck Converter through Contraction Techniques

“…The DC-DC buck power converter supplies a lower voltage than the input voltage and is one of the most widely studied power converters: Some recent applications include battery chargers [17], hybrid electric vehicles [18], quadropter's control [19], among others. The underlying topology of the buck converter is non-smooth, meaning that it switches back and forth according to a control signal, between an ON and OFF state, to guarantee a required output voltage.…”