Method and apparatus for data density-independent phase adjustment in a clock and data recovery system
First Claim
1. A clock and data recovery system comprises:
- a phase detector operably coupled to receive high data rate serial data and to recover even and odd data from the high data rate serial data based on a divided clock and to produce phase information and transition information based on the recovered even and odd data;
a lock phase adjust charge pump operably coupled to receive the phase information and transition information and to produce a current signal responsive to the phase information and transition information, wherein the lock phase adjust charge pump includes;
a phase charge pump driven by the phase information;
a transition charge pump driven by the transition information, the transition charge pump further including a programmable transition current sink;
a programmable DC bias current sink; and
at least two programmable offset bias current sinks;
a loop filter for converting the current signal to a control voltage signal;
a voltage controlled oscillator for producing a clock signal to the phase detector based on the control voltage signal;
a divider operably coupled to receive the clock signal and to produce the divided clock to the phase detector; and
control logic operable coupled to adjust the programmable transition current sink, the programmable DC bias current sink, and the at least two programmable offset bias current sinks over a plurality of n-bit buses.
1 Assignment
0 Petitions
Accused Products
Abstract
A data density independent clock and data recovery system includes a lock phase adjust charge pump operably coupled to receive phase information and transition information from a phase detector and to produce a current signal, responsive to the phase information and transition information, to a loop filter that converts the current signal to a control voltage signal operably coupled to a voltage controlled oscillator that produces a clock signal to the phase detector based on the control voltage signal. The lock phase adjust charge pump includes a phase charge pump, a transition charge pump, a programmable DC bias current sink, and two programmable offset bias current sinks. The transition charge pump includes a programmable transition current sink. The control logic operates under external control to adjust the currents conducted by the transition charge pump, the programmable DC bias current sink, and the two programmable offset bias current sinks.
23 Citations
20 Claims
-
1. A clock and data recovery system comprises:
-
a phase detector operably coupled to receive high data rate serial data and to recover even and odd data from the high data rate serial data based on a divided clock and to produce phase information and transition information based on the recovered even and odd data; a lock phase adjust charge pump operably coupled to receive the phase information and transition information and to produce a current signal responsive to the phase information and transition information, wherein the lock phase adjust charge pump includes; a phase charge pump driven by the phase information; a transition charge pump driven by the transition information, the transition charge pump further including a programmable transition current sink; a programmable DC bias current sink; and at least two programmable offset bias current sinks; a loop filter for converting the current signal to a control voltage signal; a voltage controlled oscillator for producing a clock signal to the phase detector based on the control voltage signal; a divider operably coupled to receive the clock signal and to produce the divided clock to the phase detector; and control logic operable coupled to adjust the programmable transition current sink, the programmable DC bias current sink, and the at least two programmable offset bias current sinks over a plurality of n-bit buses. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A lock phase adjust charge pump for producing a current signal responsive to phase information and transition information, comprising:
-
a phase charge pump operably coupled to receive phase information wherein the phase charge pump produces a phase charge pump current; a transition charge pump operably coupled to receive transition information, the transition charge pump further including a programmable transition current sink wherein the transition current pump produces a transition current; and a programmable DC bias current sink wherein the programmable DC bias current sink produces a DC bias current that cancels transition current upon a data transition and sums with the transition current to collectively cancel the phase charge pump current for periods in which there is no data transition. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 18, 19, 20)
-
-
16. A method to adjust a sampling point of a data-density independent lock phase adjust charge pump, the method comprising:
-
producing phase information and transition information from high data rate serial data; coupling the phase information to a phase charge pump; coupling the transition information to a transition charge pump, the transition charge pump further including a programmable transition current sink; adjusting the current conducted by the programmable transition current sink by a first delta value; adjusting the current conducted by a programmable DC bias current sink by a second delta value, wherein the second delta value is equal in magnitude but opposite in sign of the first delta value; driving the transition charge pump by the transition information so that the current conducted by the programmable transition current sink and the current conducted by the programmable DC bias current sink substantially cancel when the transition information is in a first state and sum when the transition information is in a second state; and producing the current from the lock phase adjust charge pump to a loop filter of a phase locked loop to adjust the phase information sampling point to a desired position within a bit period of the high data rate serial data. - View Dependent Claims (17)
-
Specification