Three freewheel duration optimization circuits are presented to control the freewheel period of PCCM switching converters through adjusting the peak inductor current level. These schemes successfully enhance the efficiency of the single-inductor dual-output (SIDO) switching converter. The SIDO converter works in pseudo-continuous conduction mode to enhance its driving capability. The single-charge successive-discharge scheme is also adopted to increase the flexibility of output loading ratio between outputs and reduces switching loss. A gate triggering cell is introduced to ease the implementation of gate control logic for multi-phase switching converter. The first circuit is based on the principle of phase-lock loop in defining a constant freewheel time (T_FW); the second uses the ratio...[ Read more ]

Three freewheel duration optimization circuits are presented to control the freewheel period of PCCM switching converters through adjusting the peak inductor current level. These schemes successfully enhance the efficiency of the single-inductor dual-output (SIDO) switching converter. The SIDO converter works in pseudo-continuous conduction mode to enhance its driving capability. The single-charge successive-discharge scheme is also adopted to increase the flexibility of output loading ratio between outputs and reduces switching loss. A gate triggering cell is introduced to ease the implementation of gate control logic for multi-phase switching converter. The first circuit is based on the principle of phase-lock loop in defining a constant freewheel time (T_FW); the second uses the ratio of charging and discharging currents to define T_FW; and the third adjusts T_FW according to the load current. The integrated converter is designed using a 0.35μ CMOS process. The converter works at 1MHz and the supply voltage is 2.4V. The output voltages are 3.3V and 1.8V respectively. The maximum loading current for both output is 100mA.

Two potential improvements, dynamic energy delivery sequencing and auto peak current selection are discussed qualitatively, followed by the introduction of a novel T_FW-to-peak current feedback control, which can be a suitable candidate for implementing the multiple-output switching converter.