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

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.