Research And Design Of High Efficiency Driving Method And Control Mode For Buck Converter With Large Load

With the development of electronic science and technology,the world is about to enter the era of IOT.By that time,PC,smart phones,smart appliances and virtual reality devices can be all connected by the internetworking.People can not only find out what's happening at home anytime,anywhere through the phone,but also control the smart appliances.Smart portable devices bring people both convenience and burden.For example,the battery life of smart portable devices has been criticized by people.How to keep the devices running for more time under the limited battery capacity range is becoming the focus of the current study.Power management circuit is the key way of transporting energy from battery to the power consuming circuit.So,improving the efficiency of power management circuit is a critical way to extending the battery life.Following the trends,A high efficiency Buck converter applied to wide load range and variable output voltage is presented,which conbines segmented power stage technique,adaptive gate swing technique and pulse frequency modulation techniques.The specific strategy to realize high efficiency is as follows: in the heavy load condition,the system operates in PWM control mode and all power-MOS are active;in the medium load condition,segmenting of power stage is enabled whose stage number can be changed according to the sensing current and the gate drive voltage can be regulated by LDO;in light load condition,the converter can enter the PFM control mode to reduce power loss,in which the power MOS on-time can be adaptively regulated to keep the peak inductor current conatant.The Buck converter is implemented in BCD 0.35?m process.The input voltage is 5V,but output voltage can be adjusted from 0.8V to 3.3V.The maximum load current is up to 5A.Switching frequency is fixed 1MHz in PWM control mode.The research results indicate that the proposed converter has a higher efficiency than the traditional ones with a fixed gate width,fixed gate drive voltage and single control mode.The simulation results show a maximum 6.2% efficiency improvement.