| 摘要 |
A register controlled DLL circuit occupies a relatively small area in a semiconductor device by reducing the number of flip-flops for generating timing pulses that are used to control a DLL operation and sequentially toggled. The registered controlled DLL circuit for generating a DLL clock by delaying internal clocks includes a timing pre-pulse generating unit configured to generate a plurality of timing pre-pulses activated sequentially in response to a source clock, the plurality of pre-pulses being repeated two or more times in each delay shifting update period, a mask signal generating unit configured to generating a mask signal having a logic level varied according to toggling of a predetermined one of the timing pre-pulses, and a timing pulse outputting unit configured to output the plurality of timing pre-pulses as a plurality of timing pulses in response to the mask signal.
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