Design of a synchronous boost DC–DC converter with constant current mode control in MPP

摘要

This paper introduces a constant current control mode (CCM) method for boost DC–DC converters with synchronous rectifiers. The aim is to enlarge the application range, meeting the requirement in markets of mobile power pack (MPP). Historically, the boost DC–DC converters applied in a MPP only have a constant voltage control mode (VCM) loop to provide a fixed output voltage for discharging and usually use short circuit protection to avoid chip damage when the output current exceeds the limitation value. The proposed CCM implemented with a precision buffer for reference voltage and an extra error amplifier has guaranteed a continuous current for loading in the MPP which can strongly enhance the battery life. For a proof of concept, a boost DC–DC converter was implemented with the proposed CCM in a 0.6 μm 5 V BCD SILTERRA process with an area of 2.484 mm2. The experimental results demonstrate steady conversion from VCM to CCM control. Besides, the load current boundary value in CCM achieves a variation within 10 % at both 1 and 2 A load current under different supply voltages which can meet the maximum limit of MPP application.