Duty cycle correction circuit of delay locked loop and the delay locked loop having the duty cycle correction circuit
First Claim
1. A delay locked loop comprising:
- a DLL core, which receives an external clock signal and generates an internal clock signal synchronized to the external clock signal;
a buffer, which buffers the internal clock signal and outputs differential reference clock signals; and
a duty cycle correction circuit, which generates duty rate control signals each having a predetermined offset corresponding to a difference of respective duty cycles of the differential reference clock signals; and
a control signal generation circuit, which generates switching control signals for controlling the offset, and outputs the switching control signals to the duty cycle correction circuit, wherein the DLL core corrects a duty cycle of the internal clock signal, in response to the duty rate control signals.
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Abstract
There is provided a Delay Locked Loop (DLL) including a duty cycle correction circuit capable of controlling a duty error, when the duty error is generated in the DLL. The duty cycle correction circuit controls amounts of electric charges accumulated in storage units, in response to switching control signals received from the external, and outputs duty rate control signals each corresponding to a difference between the amounts of electric charges accumulated in the storage units. Therefore, the DLL including the duty cycle correction circuit can correct a duty cycle of a reference clock signal, in response to the duty rate control signals, and can output a reference clock signal with a duty cycle of 50%.
28 Citations
2 Claims
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1. A delay locked loop comprising:
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a DLL core, which receives an external clock signal and generates an internal clock signal synchronized to the external clock signal;
a buffer, which buffers the internal clock signal and outputs differential reference clock signals; and
a duty cycle correction circuit, which generates duty rate control signals each having a predetermined offset corresponding to a difference of respective duty cycles of the differential reference clock signals; and
a control signal generation circuit, which generates switching control signals for controlling the offset, and outputs the switching control signals to the duty cycle correction circuit, wherein the DLL core corrects a duty cycle of the internal clock signal, in response to the duty rate control signals. - View Dependent Claims (2)
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Specification