Semiconductor integrated circuit device operating in synchronism with clock and method for controlling duty of clock

Abstract

A semiconductor integrated circuit device includes a processor, a first clock generating section and a control section. The processor core operates in synchronism with a first clock and includes first and second critical paths. The first clock generating section controls a duty of an externally input second clock to generate the first clock. a control section detects a first phase difference between the first clock and a third clock obtained by delaying the first clock by a delay time in the first critical path and a second phase difference between the first clock and a fourth clock obtained by delaying the first clock by a delay time in the second critical path. The control section instructs the first clock generating section to control the duty so as to minimize a difference between the first and second phase differences.