Clock generator
First Claim
Patent Images
1. A circuit for generating a series of high speed clock signals comprising:
- a reference clock signal; and
a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of delay cells and in response thereto, supply a first control voltage indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the first control voltage varying from a first potential to a second potential, and a second control voltage, indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the second control voltage varying from the second potential to the first potential,wherein the plurality of delay cells are serially connected stages, each cell supplying a clock signal in response to changes in the first and second phase frequency detector control voltages, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, and a last cell feeding back to a first cell in the plurality, whereby the clock signals from the plurality of delay cells forms a series of multiple subfrequency clock signals evenly spaced from the reference clock signal, wherein a delay cell comprises;
a first transistor, coupled between the first potential and a first node having a control electrode coupled to the first node;
a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage;
a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; and
a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to a second bias voltage.
0 Assignments
0 Petitions
Accused Products
Abstract
A system for converting between parallel data and serial data is described. In the system (10), individual bits of the parallel data (12) are latched into individual registers (117). Each register (117) is coupled to a corresponding AND gate (110) which is also connected to receive phased clock signals. The output terminals of the AND gates (110) are connected to an OR gate (115). Using the system, with appropriately phased clocks, the parallel data is converted into serial data.
41 Citations
21 Claims
-
1. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; and a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of delay cells and in response thereto, supply a first control voltage indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the first control voltage varying from a first potential to a second potential, and a second control voltage, indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the second control voltage varying from the second potential to the first potential, wherein the plurality of delay cells are serially connected stages, each cell supplying a clock signal in response to changes in the first and second phase frequency detector control voltages, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, and a last cell feeding back to a first cell in the plurality, whereby the clock signals from the plurality of delay cells forms a series of multiple subfrequency clock signals evenly spaced from the reference clock signal, wherein a delay cell comprises; a first transistor, coupled between the first potential and a first node having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; and a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to a second bias voltage. - View Dependent Claims (2, 3, 4, 5, 6, 8, 14)
-
-
7. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; and a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of delay cells and in response thereto, supply a first control voltage, indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the first control voltage varying from a first potential to a second potential, and a second control voltage, indicative of a phase difference between the reference clock signal and the output of one of the plurality of delay cells, the second control voltage varying from the second potential to the first potential, wherein the plurality of delay cells are serially connected stages, each cell supplying a clock signal in response to changes in the first and second phase frequency detector control voltages, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, a last cell feeding back to a first cell in the plurality, whereby the clock signals from the plurality of delay cells forms a series of multiple subfrequency clock signals evenly spaced from the reference clock signal, wherein each delay cell comprises; a first transistor, coupled between the first potential and a first node, having a control electrode coupled to the first node; a second transistor, coupled between the first node and a first output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the first node and a second output node, having a control electrode coupled to the first bias voltage, wherein the second output node provides an inverse of a signal at the first output node; a fourth transistor, coupled between the first output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; a fifth transistor, coupled between the second output node and the second node, having a control electrode coupled to an inverse of the output of one of the plurality of delay cells; and a sixth transistor, coupled between the second node and the second potential, having a control electrode coupled to a second bias voltage.
-
-
9. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; a phase frequency detector, generating a control signal indicating a phase difference between a first edge of the reference clock signal and a selected clock signal of the series of high speed clock signals; a first delay cell, generating a first output signal and a second output signal, wherein the first delay cell is coupled to an output signal from a second delay cell and an inverse of the second delay cell output signal, wherein the first delay cell decreases its switching time as the control signal increases, and the first delay cell increases its switching time as the control signal decreases, and the first delay cell comprises; a first transistor, coupled between the first potential and a first node having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; and a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to a second bias voltage. - View Dependent Claims (10, 11, 12, 13)
-
-
15. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of serially connected stages of delay cells and in response thereto supply a first control voltage indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells, the first control voltage varying from a first potential to a second potential, and a second control voltage, indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells, the second control voltage varying from the second potential to the first potential; a charge pump, coupled to the first and the second phase frequency detector control voltages, generating a control signal; and the plurality of serially connected stages of delay cells, each cell coupled to receive the charge pump control signal and in response thereto supplying a clock signal, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, each delay cell decreasing its switching time when the charge pump control signal increases and increasing its switching time when the charge pump control signal decreases, one of the cells in the plurality supplying a clock signal to a different cell in the plurality, and a cell in the plurality supplying a clock signal to the phase frequency detector, wherein each delay cell comprises; a first transistor, coupled between the first potential and a first node, having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; and a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to the control voltage; whereby a series of multiple subfrequency clock signals is generated which are evenly spaced from the reference clock signal. - View Dependent Claims (16, 18, 20)
-
-
17. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of serially connected stages of delay cells and in response thereto supply a first control voltage indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells, the first control voltage varying from a first potential to a second potential, and a second control voltage, indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells, the second control voltage varying from the second potential to the first potential; and a charge pump, coupled to the first and the second phase frequency detector control voltages, generating a control signal, wherein each cell of the plurality of serially connected stages of delay cells is coupled to receive the charge pump control signal and in response thereto supply a clock signal, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, each delay cell decreasing its switching time when the charge pump control signal increases, and increasing its switching time when the charge pump control signal decreases, one of the cells in the plurality supplying a clock signal to the phase frequency detector, whereby a series of multiple subfrequency clock signals is generated are evenly spaced from the reference clock signal, wherein each delay cell comprises; a first transistor, coupled between the first potential and a first node, having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the plurality of delay cells; and a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to the control signal.
-
-
19. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; a phase frequency detector coupled to receive the reference clock signal and an output of one of a plurality of serially connected stages of delay cells and in response thereto supply a first control voltage indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells from a first potential to a second potential, and a second control voltage indicative of transitions of the reference clock signal and the output of one of the plurality of delay cells from the second potential to the first potential; a charge pump, coupled to the first and the second phase frequency detector control voltages, generating a control signal, wherein each cell of the plurality of serially connected stages of delay cells is coupled to receive the charge pump control signal and in response thereto supplying a clock signal, each cell connected to receive the clock signal from a preceding cell and supply it to a following cell after delaying it, each delay cell decreasing its switching time when the charge pump control signal increases and increasing its switching time when the charge pump control signal decreases, one of the cells in the plurality supplying a clock signal to a different cell in the plurality, and a cell in the plurality supplying a clock signal to the phase frequency detector, whereby a series of multiple subfrequency clock signals is generated which multiple subfrequency clock signals are evenly spaced from the reference clock signal; a replica bias circuit, coupled to the plurality of serially connected stages of delay cells, wherein the replica bias circuit minimizes switching effects of the delay cells on the series of multiple subfrequency clock signals, and comprises; a first transistor, coupled between the first potential and a first node, having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to a second bias voltage; and a fourth transistor, coupled between the second node and the second potential, having a control electrode coupled to the control signal.
-
-
21. A circuit for generating a series of high speed clock signals comprising:
-
a reference clock signal; a phase frequency detector coupled to receive the reference clock signal and an output from a first delay cell and in response thereto generating a control signal; and a second delay cell, coupled to the control signal and an output signal from the first delay cell, wherein the second delay cell comprises; a first transistor, coupled between a first potential and a first node, having a control electrode coupled to the first node; a second transistor, coupled between the first node and an output node, having a control electrode coupled to a first bias voltage; a third transistor, coupled between the output node and a second node, having a control electrode coupled to an output of one of the at least one delay cell; and a fourth transistor, coupled between the second node and a second potential, having a control electrode coupled to the control signal.
-
Specification