Lee, BumkilSong, Min KyuMaity, AhsisMa, Dongsheng (Brian)2020-03-192020-03-192019-02-220018-9200http://dx.doi.org/10.1109/JSSC.2019.2895240https://hdl.handle.net/10735.1/7413Due to copyright restrictions and/or publisher's policy full text access from Treasures at UT Dallas is limited to current UTD affiliates (use the provided Link to Article).In order to meet stringent power requirements in modern application processors, a 25-MHz four-phase dc-dc power converter is presented. It employs an adaptive window hysteretic control to facilitate ultra-fast transient response and minimize output voltage (VO) undershoot and overshoot during load transient periods. Inherent clock synchronization ability ensures current balancing between phase sub-converters. The control also enables a wide range of programmable VO for dynamic voltage/frequency scaling. To maintain high efficiency over a wide power range without degrading transient speed, a 1-cycle active phase count scheme is introduced. A design prototype was fabricated in a 0.35-μm CMOS process with an active die of 1.88 mm2. Simple circuit structure benefits a power density of 3.98 W/mm2. At a switching frequency of 25 MHz and a nominal input of 3.3 V, it regulates a programmable VO ranging from 0.3 to 2.5 V. It achieves more than 80% efficiency over 96.7% of power range with a peak value of 88.1%. In response to 4-A load step-up/down, it achieves 103 mV/123 mV VO undershoot/overshoot with 1% settling time of 190 ns/237 ns, respectively. ©2019 IEEE.en©2019 IEEESynchronization--Clocks and watchesConverters, Switch mode powerElectric invertersHysteresisMechanical clocks and watchesTransients (Dynamics)--AnalysisDC-to-DC convertersarticleLee, B., M. K. Song, A. Maity, and D. Brian Ma. 2019. "A 25-MHz Four-Phase SAW Hysteretic Control DC-DC Converter with 1-Cycle Active Phase Count." IEEE Journal of Solid-State Circuits 54(6): 1755-1763, doi: 10.1109/JSSC.2019.2895240546