Townsend and Townsend and Crew LLP
Delay locked loop for use in semiconductor memory device
It is provided a delay locked loop for obtaining a reduced jitter and a stable time delay adjustment to thereby perform a bi-directional time delay with a small area even at low frequency applications. The delay locked loop includes an input unit for receiving a clock signal and a non-clock signal and comparing received signals to produce an internal clock signal, a controller for receiving the internal clock to produce a control signal, a bi-directional oscillator, responsive to the control signal from the control means, for performing a ring oscillation in a first or second direction and fulfilling an addition and subtraction adjustment function for a time delay, a counter for receiving an output signal of the bi-directional oscillator and counting the number that the signal is passed therethrough, and an AND gate for performing a combination operation on the outputs of the bi-directional oscillating means and the counting means, to produce the result as a final internal clock signal.
Hynix Semiconductor
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G11C H03K H03L H03K G11C
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Seong-Hoon
Lee