Fast and high efficiency hysteretic buck converter

Mobile battery powered platforms have to focus on high efficiency to increase their on times. In addition to high efficiency, their components have to work under a varying battery voltage to obtain stable operation. To answer these needs switching DC-DC converters are used to produce a stable voltage output needed by mobile platforms and its peripherals with high efficiency to increase standby time. Also as a main design target, the converter should respond to the load variation as fast as possible to produce a reliable output voltage. Hysteretic converters are known to have fast load variation responses and a hysteretic converter scheme is utilized for the design in this thesis. Another important target of mobile platforms is that to decrease bill of materials as much as possible to reduce total price of the device in a challenging competitive market condition. This thesis introduces a hysteretic buck converter to produce two different output voltages utilizing a single inductor. Also, using a single inductor, the cost of one inductor is reduced from the total budget. However, to produce two separate voltage outputs with a single inductor has a drawback of cross talk between outputs which is called cross regulation. This single inductor double output (SIDO) hysteretic buck converter focuses mainly on increasing efficiency and reducing the cross regulation for better regulation of the outputs. After a brief description of the DC-DC converters, the designed SIDO hysteretic buck converter and its sub blocks are explained in detail. Finally, top level post-layout simulation results are compared with state of art SIDO buck converters.