Delay locked loop (DLL) using an oscillator and a counter and a clock synchronizing method
First Claim
1. A delay locked loop (DLL) comprising:
- a time-to-digital converter for receiving an input clock signal and converting a period (T) of the input clock signal into a digital signal to generate coarse cycle information signals and fine cycle information signals;
a first cycle delay unit for generating a first cycle clock signal delayed by T/2 from an internal clock signal and half cycle information signals in response to the coarse cycle information signals and fine cycle information signals;
a second cycle delay unit for generating a second cycle clock signal delayed by T/4 from the input clock signal in response to the coarse cycle information signals and half cycle information signals; and
a clock recovery unit for generating the internal clock signal and output clock signals in response to the first and second cycle clock signals.
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Accused Products
Abstract
Provided are a delay locked loop (DLL) using an oscillator and a counter and a clock synchronizing method. The DLL converts cycle information of an input clock signal into digital information using the oscillator and the counter and generates output clock signals from the input clock signal using the digital information after a predetermined delay time elapses. The output clock signals each have a duty cycle of 50%. The DLL includes: a time-to-digital converter for converting one period (T) of the input clock signal into a digital signal to generate coarse cycle information signals and fine cycle information signals; a first cycle delay unit for generating a first cycle clock signal delayed by T/2 from an internal clock signal and half cycle information signals in response to the coarse cycle information signals and the fine cycle information signals; a second cycle delay unit for generating a second cycle clock signal delayed by T/4 from the input clock signal in response to the coarse cycle information signals and half cycle information signals; and a clock recovery unit for generating the output clock signals in response to the first and second cycle clock signals.
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Citations
24 Claims
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1. A delay locked loop (DLL) comprising:
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a time-to-digital converter for receiving an input clock signal and converting a period (T) of the input clock signal into a digital signal to generate coarse cycle information signals and fine cycle information signals; a first cycle delay unit for generating a first cycle clock signal delayed by T/2 from an internal clock signal and half cycle information signals in response to the coarse cycle information signals and fine cycle information signals; a second cycle delay unit for generating a second cycle clock signal delayed by T/4 from the input clock signal in response to the coarse cycle information signals and half cycle information signals; and a clock recovery unit for generating the internal clock signal and output clock signals in response to the first and second cycle clock signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A delay locked loop (DLL) comprising:
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a time-to-digital converter for receiving an input clock signal and converting a period (T) of the input clock signal into a digital value to generate coarse cycle information signals and fine cycle information signals; a first cycle delay unit for receiving the coarse cycle information signals, the fine cycle information signals and an internal clock signal, to generate a first clock signal delayed by a first delay time from the internal clock signal and a first cycle information signal; a second cycle delay unit for receiving the coarse cycle information signals, the first cycle information signal and the input clock signal, to generate a second clock signal delayed by a second delay time from the input clock signal; and a clock recovery unit for receiving the first and second clock signals to generate output clock signals that are delayed by the first delay time from the internal clock signal and the input clock signal and have a duration corresponding to the second delay time. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A clock synchronizing method comprising:
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receiving an input clock signal and converting a period (T) of the input clock signal into a digital signal to generate coarse cycle information signals and fine cycle information signals; generating a first cycle clock signal delayed by a first delay time from an internal clock signal and half cycle information signals in response to the coarse cycle information signals and the fine cycle information signals; generating a second cycle clock signal delayed by a second delay time from the input clock signal in response to the coarse cycle information signals and the fine cycle information signals; generating the internal clock signal delayed by the first delay time from the input clock signal in response to the first and second cycle clock signals; and generating output clock signals delayed by the second delay time from the input clock signal the output clock signals having a duration corresponding to the second cycle time in response to the first and second cycle clock signals. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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Specification