| This thesis proposes an auto-buck-boost single inductor dual output?SIDO?dc-dc converter with hysteretic current and charge control.The inductor current of the converter controled by three reference current,The three reference current divide the inductor current into four intervals,therefore,the proposed converter works in either boost-dominated mode or buck-dominated mode,without an overlap of charging and discharging phase,which maintains high power efficiency because of minimized average inductor current.Every channel of the proposed converter is controlled by a charge control circuit,and each channel has an independent charging period.Hence,the last channel is not suffered from dependent duty cycle and cross regulations is reduced.Because of large bandwidth of the comparator controlled current loop,while the converter works in buck dominated mode,the inductor current may be unstable,and thus a compensation ramp is added.When the converter operates in boost dominated mode,a charging period is required and both switching frequency decrease and inductor current ripple increase.Hence,a additional current4)?6? is add into charge control circuit to reduce the frequency variation in boost dominated mode.The additional current4?6? can degenetate the cross regulation.And because the switching frequency of the converter is not fixed,the cross regulation can allocation to two channels,then,there will not apear one of the channel's cross regulation be too high.The proposed converter is implemented in Global Foundries 1P6M 0.18m CMOS technology.The input voltage range is 2.8V-5V,The output voltage range is 2.5V-5V.The maximum output current is 4508.According to the simulation result,the peak efficiency is95.1%,the switching frequency range is 1-3.The cross-regulation range is 0.015-0.077?1/,the recover-time range of load transient less than 60,the undershoot and overshoot voltage range of load transient is 15-638?,under the load current change of 3008). |
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