Delay-Locked loop With Dynamically Biased Charge Pump

Abstract

A delay-locked loop, including a phase detector configured to receive two signals, one of the signals being delayed relative to the other of the signals, the phase detector having an UP output and a DOWN output. The delay-locked loop also includes a charge pump system operatively coupled with the phase detector, the charge pump system including (1) a charge pump configured to be responsive to assertion of actuating signals from the UP output and the DOWN output so as to control pumping of charge from the charge pump system, such pumped charge being usable to control a delay line carrying one of the two signals, so as to control relative delay occurring between the two signals; and (2) a feedback control loop configured to dynamically adjust at least one bias signal at the charge pump so as to minimize net charge pumped from the charge pump system during simultaneous assertion of actuating signals from the UP output and the DOWN output.

1 . A delay-locked loop, comprising:
 a first delay line;   a second delay line;   a phase detector coupled to the first and second delay line, the phase detector including an UP output and a DOWN output; and   a charge pump system including:
 a charge pump having a first switch coupled with a first current source and configured to be actuated via assertion of an actuating signal from the UP output, and a second switch coupled with a second current source and configured to be actuated via assertion of an actuating signal from the DOWN output, the charge pump system being adapted so that biasing of the current sources and actuation of the switches controls pumping of charge to an output of the charge pump system, which in turn is usable to control a relative amount of delay occurring between the first and second delay lines; and 
 a feedback control loop configured to dynamically bias at least one of the first current source and the second current source so that substantially no net charge is pumped to the charge pump output upon simultaneous actuation of the first switch and the second switch of the charge pump. 
   
   
   
       2 . The delay-locked loop of  claim 1 , where the charge pump system includes a charge pump replica adapted to replicate operation of a portion of the charge pump when the first switch and the second switch of the charge pump are simultaneously activated. 
   
   
       3 . The delay-locked loop of  claim 2 , where the charge pump replica is adapted to dynamically generate a biasing signal which causes an output level of the charge pump replica to be substantially equal to an output level of the charge pump. 
   
   
       4 . The delay-locked loop of  claim 3 , where the biasing signal is applied to both the charge pump replica and the charge pump. 
   
   
       5 . A delay-locked loop, comprising:
 a phase detector configured to receive two signals, one of the signals being delayed relative to the other of the signals, the phase detector having an UP output and a DOWN output; and   a charge pump system operatively coupled with the phase detector and including:
 a charge pump configured to be responsive to assertion of actuating signals from the UP output and the DOWN output so as to control pumping of charge from the charge pump system, such pumped charge being usable to control a delay line carrying one of the two signals, so as to control relative delay occurring between the two signals; and 
 a feedback control loop configured to dynamically adjust at least one bias signal at the charge pump so as to minimize net charge pumped from the charge pump system during simultaneous assertion of actuating signals from the UP output and the DOWN output. 
   
   
   
       6 . A delay-locked loop, comprising:
 a first delay line;   a second delay line;   a phase detector coupled to outputs of the first and second delay lines, the phase detector including an UP output and a DOWN output;   a charge pump coupled to the phase detector so that the UP output of the phase detector is coupled to a first charge pump input and so that the DOWN output of the phase detector is coupled to a second charge pump input, where the charge pump is configured to pump charge via a charge pump output based on a bias condition and on levels at the first charge pump input and the second charge pump input; and   a charge pump replica coupled with the charge pump and configured to dynamically adjust the bias condition so that, in response to an assertion condition at the first charge pump input and the second charge pump input, the charge pump pumps a net charge that tends toward a desired value associated with such assertion condition.