Invention Grant
US09543967B2 DLL circuit and semiconductor device 有权
DLL电路和半导体器件

DLL circuit and semiconductor device
Abstract:
In accordance with disclosed embodiments, a DLL circuit includes a variable frequency division circuit that uses a variable frequency division ratio to frequency-divide a first clock signal to generate first and second frequency-divided clock signals, a grain size change circuit that changes the count width in synchronization with the first frequency-divided clock signal, a counter circuit that updates the count value in accordance with the count width in synchronization with the second frequency-divided clock signal, and a variable delay circuit that delays the first clock signal on the basis of a delay amount that is in accordance with the count value, thereby generating a second clock signal. When the relationship in magnitude between the phase difference between the first and second clock signals and a predetermined value becomes inverse just after the updating of the count value, the grain size change circuit changes the count width, and the variable frequency division circuit sets the frequency division ratio of the second frequency-divided clock signal being greater than that of the first frequency-divided clock signal.
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