| With the rapid development of moderm portable devices,such as smartphones,tablets,notebooks and so on,their central processing units(CPU)show better performance.It brings more complex power supply requirements to the power management circuits.In this way,to meet their needs,this thesis emphasizes on the key technologies of power management integrated circuits with various input ranges.Aiming at the low voltage,high currelt power supply,which is adopted by the central processor in flat panels and smart phones,an enhanced current-balancing technology with offset correction function for dual-phase buck converters is proposed in this thesis.It could equally distribute the load current between phases in both continuous and discontinuous conduction modes just by sensing the inductor currents of the upper power switches.Moreover,aiming at the generation mechanism of output voltage ripples in dual-phase buck converters,a ripple elimination technology based on interleaved synchronous clocks and self-calibrated interleaving-time generator is proposed,which makes phases precisely interleaved in the full load range.Then it reduces the amplitude of output ripple.Based on enhanced current-balancing and ripple elimination technology,a high performance integrated dual-phase buck converter is designed and implemented,It also includes ripple-based adaptive on-time control logic,self-calibrated zero-current switching and robust driving logic.Finally,the characteristics are validated by tape-out and experimental results in 0.18?m BCD process.The maximum load current is 6A and the peak efficiency reaches 91%.The current imbalance is less than 0.6%and the output ripple is restricted under 9mV.Compared with state-of-art works,it shows better comprehensive performance.To fulfill the demand of high performance low consumption power supply for portable devices,a quiescent power optimization technology is proposed,which provides a low-power-mode for four-phase Buck converters under extremely light load conditions.It also ensures smooth mode switching by using hysteretic logic.What is more,an improved high-precision current sensing technology with current mirrors is proposed.Combining with adaptive on-time control,master-slave current-balancing mechanism,integrated high-frequency synchronous clock,over-current protection and under-current protection,it ensures safety and good performance.Finally,a fUlly-integrated four-phase buck converter with 12A maximum load current is designed and implemented.The characteristics of the converter are verified by tape-out and test results.The converter only consumes 7?A quiescent current while performing similarly with other works.To meet the demand of typical 12 V-l.x V high step-down ratio,high current density power supply for laptop processors,the 4-phase design with high current capability takes the advantages of series-capacitor buck converter topology,such as doubled duty ratio and half voltage stress of power switches.Then a novel four-phase current-balancing technology based on adaptive on-time control is proposed,which reduces the risk of inductor current saturation,saves the number of current sensors and minimizes the volume of the converter.Moreover,by using gate driving protection and high-voltage-side power switch driver which has floating power supply and zero quiescent power dissipated level-shifters,the power efficiency and current density are optimized with GaN power devices.Finally,a four-phase series-capacitor buck converter with high step-down ratio is designed,and the above characteristics are tested and verified.The converter achieves 92.5%peak efficiency and 10 A full-load current at 12 V-1.2 V step-down ratio.The switching frequency reaches 2.5 MHz in each phase.The current density is 460.8A/cm3and the total volume of external devices is 21.7mm3.It is superior compared with state-of-art works. |
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