Abstract
The study of rising the voltage of AAA batteries from 1.5V to 3.3V was investigated to supply the power of the Walkman designed for MP3. Five step-up converters, MAX1674、RT9262、XC6832、AIC1639、and RN5RK, were selected to improve the circuits of the walkman. Among the converters, the most suitable one need to be chosen according to conversion efficiency、start-up voltage、loading current、and price。 In power management, operating voltage was modulated under 3.3V、3.0V、2.7V for the effect of the system. According to the power management of MP3, several different circuits were designed to make the system more efficient。 According to the result of the experiment tested under one battery, MAX1674 step-up circuit was the best choice under synchronous rectifier technique. Except high conversion efficiency，MAX1674 step-up circuit also showed excellent performance in the aspect of start-up voltage and loading current. Decreasing of the operating voltage came along with the longer lifetime of batteries. At 2.7V， the lifetime of batteries was the longest. If the operating voltage was under 2.7V， there would be some errors in the system。