Duty compensation device

Abstract

A duty compensation device of one embodiment has a structure capable of more accurately setting a duty of a clock within an appropriate range. The duty compensation device comprises a duty adjusting unit, a duty measuring unit, a controlling unit. The duty measuring unit generates a sampling clock of a frequency fn that is asynchronous to the clock over an n-th period Tn (n=1 to N and N is an integer of 3 or more), and obtains measurement information for specifying the duty of the clock by using the sampling clock. The controlling unit determines a control code to be given to the duty adjusting unit based on control code candidates obtained for each of the N periods T1 to TN and the control code candidates in which the duty specified by measurement information obtained by the duty measuring unit is within a predetermined range.

Description

technical field [0001] The invention relates to a duty ratio compensation device for compensating the duty ratio of a clock. Background technique [0002] Digital circuits are generally designed to operate in synchronization with a clock. That is, the digital circuit transitions to a new logic state at the timing of both rising and falling of the clock, or any one of them. Alternatively, the digital circuit transitions to a new logic state at the timing of rising or falling of each phase clock constituting the multiphase clock. [0003] In digital circuits, it is important that the duty cycle of the clock is in the proper range. Using the high time t H ratio to period T (t H / T) indicates the duty cycle of a single-phase clock. The duty ratio of the two-phase clock is represented by the ratio of the high-level time of one of the two complementary clocks constituting the two-phase clock to the period. [0004] If the duty ratio of the clock is out of an appropriate rang...

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