Design Of A Low Quiescent Current Tri-mode Boost DC-DC Converter With High Efficiency

With the rapid development of electronic technology,the portable electronic equipments are more and more convenient and enriching people’s lives.Portable electronic equipments are often powered by batteries,which store a limited amount of energy.Therefore,in order to prolong the battery life of the portable electronic equipments,higher requirements are placed on the power management unit.Since portable electronic equipments generally have a wide load range and are in standby state for a long time,this requires a power management unit that can achieve high efficiency in the full load range and can reduce the quiescent current under light load.Based on such application requirements,a low quiescent current tir-mode Boost DCDC converter with high efficiency is presented for portable electronic equipments.The proposed converter adopts the synchronous rectification topology controlled by the hysteresis current mode,the inductor current ripple value is kept constant by a full-cycle current sampling circuit and a hysteresis comparator.When the load is heavy,the proposed converter works in continuous conduction mode(CCM).As the load decreases,it smoothly switches to discontinuous conduction mode(DCM)when the zero current detector(ZCD)detects the zerocrossing point of the inductor current,which the switching losses are reduced and reverse inductor current is avoided,and improving efficiency at medium load.For light load,a novel quasi burst mode(QBM)is proposed to achieve low quiescent current and high efficiency,in which the proposed converter will enter a sleep state,and most modules are turned off to retain only the QBM controller,low-power current bias and sample-and-hold circuits.The proposed converter was implemented by using Dongbu 0.13μm BCD process with an area of 1100μm×780μm.It can output 5.0V at the input voltage of 3.0V～4.2V and full load,with the line regulation rate of 0.1067%/V and the load regulation rate of 0.0116%/mA.At load of 10μA,its efficiency is higher than 75% and the quiescent current is less than 800 nA.In addition,it can automatically and smoothly switch between CCM,DCM and QBM according to the load to achieve the high efficiency,and the peak efficiency is 95.65%.It can be seen that the proposed converter has excellent performance and meets the requirements of practical applications.