CDR circuit, reception apparatus, and communication system

1. A reception apparatus comprising:

a Clock Data Recovery circuit, abbreviated as a CDR circuit, configured to receive a serial data signal propagated over a data line and regularly inserted with a signal transition to recover a clock and data in accordance with the received serial data signal, said CDR circuit including

a divider having a delay element for extracting, as a trigger, a data input regularly inserted with a signal transition and

a latch for latching an input data signal in synchronization with a clock extracted by said divider,

wherein said divider has

a flip-flop configured to enter data from a data input terminal of said flip-flop in synchronization with an input signal into a clock input terminal of said flip-flop and output the held data from a data output terminal of said flip-flop as an extraction clock, and

one of one delay element connected to said data output terminal of said flip-flop and a plurality of delay elements cascaded to said data output terminal of said flip-flop;

each of said delay elements outputs an extracted clock obtained by delaying an input clock; and

an inverted signal of an output extracted clock of any one of said one delay element and said plurality of delay elements is supplied to said data input terminal of said flip-flop.

2. The reception apparatus according to claim 1 , wherein said flip-flop is of a both-edge trigger type that synchronizes with rising and falling edges of an input data signal transition.

3. The reception apparatus according to claim 2 , wherein said flip-flop is of a differential both-edge-trigger type having a data input terminal and an inverted data input terminal and a data output terminal and an inverted data output terminal, thereby outputting an extracted clock from said data output terminal and an extracted inverted clock from said inverted data output terminal; and

said each delay element includes a normal-side input terminal in which an extracted clock is entered, an inverted input terminal in which an extracted inverted clock is entered and a normal-side output terminal from which an extracted clock is outputted and an inverted output terminal from which an extracted inverted clock is outputted,

said data input terminal of said flip-flop being supplied with one of an output extracted inverted clock of said one delay element and an output extracted inverted clock of any one of said plurality of delay elements,

said inverted data input terminal of said flip-flop being supplied with one of an output extracted clock of said one delay element and an output extracted clock of any one of said plurality of delay elements.

4. The reception apparatus according to claim 1 , further comprising:

a plurality of latches configured to latch an input data signal in synchronization with an output clock of said flip-flop and a clock outputted from one of said one delay element and said plurality of delay elements.

5. A clock data recovery circuit comprising:

a clock input terminal of a divider flip-flop electrically connected to a supply line, said supply line being electrically connected to a data input terminal of a first latch flip-flop and to a data input terminal of a second latch flip-flop;

a normal-side output terminal of the divider flip-flop electrically connected to a clock input terminal of the first latch flip-flop and to a normal-side input terminal of a first delay element, an input terminal of a phase comparator being electrically connected to said normal-side output terminal of the divider flip-flop.

6. The clock data recovery circuit according to claim 5 , further comprising:

an output of the phase comparator electrically connected to a control terminal of the first delay element.

7. The clock data recovery circuit according to claim 5 , further comprising:

a normal-side output terminal of the first delay element electrically connected to a normal-side input terminal of a second delay element.

8. The clock data recovery circuit according to claim 7 , further comprising:

a clock input terminal of a third latch flip-flop electrically connected to said normal-side output terminal of the first delay.

9. The clock data recovery circuit according to claim 7 , further comprising:

a normal-side output terminal of the second delay element electrically connected to a normal-side input terminal of a third delay element.

10. The clock data recovery circuit according to claim 9 , further comprising:

a normal-side output terminal of the third delay element configured to output a third delay element clock, said divider flip-flop being configured to receive an inverted signal of the third delay element clock.

11. The clock data recovery circuit according to claim 10 , further comprising:

a fourth delay element configured to output a fourth delay element clock, said normal-side output terminal of the third delay element being electrically connected to a normal-side input terminal of the fourth delay element.

12. The clock data recovery circuit according to claim 11 , further comprising:

another input terminal of the phase comparator being configured to receive an inverted signal of the fourth delay element clock.

13. The clock data recovery circuit according to claim 5 , further comprising:

an inverted clock input terminal of the second latch flip-flop electrically connected to said normal-side output terminal of the divider flip-flop.

14. The clock data recovery circuit according to claim 5 , further comprising:

an inverted clock input terminal of the divider flip-flop electrically connected to said supply line.

15. The clock data recovery circuit according to claim 5 , further comprising:

an inverted output terminal of the divider flip-flop electrically connected to a clock input terminal of the second latch flip-flop and to an inverted clock input terminal of the first delay element.

16. A reception apparatus comprising:

the clock data recovery circuit according to claim 5 , said clock input terminal of the divider flip-flop being configured to receive a serial data signal.

17. A communication system comprising:

the reception apparatus according to claim 16 ;

a transmission apparatus configured to transmit said serial data signal to said supply line.