Patent ID: RE40939

Claim:
A multi-phase-locked loop for data recovery comprising a phase detector, a charge pump, a loop filter and a voltage controlled oscillator, wherein: said phase detector is constituted by N phase detection units (U 1 , U 2 , . . . , U N , N is even, N≧4); said N phase detection units are connected in cascade configuration, and each phase detection unit contains : a data signal input terminal for receiving a data signal from outside; a clock signal input terminal for receiving the one of multi-phase clock signals (CK 1 , CK 2 , . . . , CK N ) from outside; a delay signal input terminal for receiving a delay signal output from another phase detection unit; a delay signal output terminal for outputting a delay signal of the phase detection unit ; and a charge/discharge control signal output terminal for outputting a control signals for charge/discharge operations; each of said N phase detection units generates a delay signal (D 1 , D 2 , . . . , D N ) according to an input the data signal and the complement of a the multi-phase clock signal; the delay signal (D j+1 ) generated by the (j+1) th phase detection unit is input into the j th phase detection unit via the j th delay signal input terminal; the delay signal (D 1 ) generated by the first phase detection unit is input into the N th phase detection unit via the N th delay signal input terminal; the j th phase detection unit ( U j ′ U j , 1≦j<N, j is a positive integer) generates one of the control signals (dn 1 , dn 2 , . . . , dn N/2 , up N/2 , . . . , up 2 ) for charge/discharge operations according to the delay signal (D j ) from the j th phase detection unit, the delay signal (D j+1 ) from the (j+1) th phase detection unit, and the multi-phase clock signal (CK j ) which is applied to the j th phase detection unit; the N th phase detection unit generates a charge control signal (up 1 ) according to the delay signal (D n ) from the N th phase detection unit, the delay signal (D 1 ) from the first phase detection unit, and the multi-phase clock signal (CK N ) which is applied to the N th phase detection unit; said charge pump being constituted by N/2 charge and discharge units (CP 1 , CP 2 , . . . , CP N/2 ), wherein the k th (CP k , 1≦k≦N/2) charge and discharge unit (CP k ) is employed to receive the k th charge/discharge control signal set (up k /dn k ) from said phase detector, and a current Ich k is generated by the charge/discharge control signal set (up k /dn k ); the charge/discharge current Ich k =(w k ×up k −w k ×dn k )Iss, wherein w k is a weighting value, Iss is a fixed current value, and w 1 <w 2 < . . . <w N/2 ; the total charge/discharge current (Ich) from said charge pump equals to Ich 1 +Ich 2 + . . . Ich k + . . . +Ich N/2 ; and said voltage controlled oscillator is a multi-phase voltage controlled oscillator, which outputs N multi-phase clock signals (CK 1 , CK 2 . . . , CK N ), which are applied to said phase detectors phase detection units , respectively.