Masahiro Sasaki Hirofumi Matsuo Fujio Kurokawa Yasuhiro Mimura Static Characteristics of the Digital PWM and/or PFM Controlled Switching DC-DC Converters. 645-650 2007 90-B IEICE Transactions 3 http://dx.doi.org/10.1093/ietcom/e90-b.3.645 db/journals/ieicet/ieicet90b.html#SasakiMKM07