Lattice Semiconductor Corporation

Harald Weller

Om P Agrawal

Ludmil Nikolov

Shyam Chandra

Douglas Morse

Hans W Klein

Ji Zhao

Geoffrey R Rickard

Michael G France

In one embodiment, a clock distribution chip includes a clock input adapted to receive an input clock signal, clock dividers each adapted to receive a clock signal based on the first input clock signal and to generate a divided clock signal, and programmable clock outputs adapted to provide output clock signals. The clock outputs are configurable to support a number of signaling standards. A programmable switch fabric is coupled between the clock dividers and the clock outputs and is configurable to provide the divided clock signals to the clock outputs.

Clock distribution chip

In one embodiment, a clock distribution chip includes a first clock input adapted to receive a first single-ended input clock signal, a second clock input adapted to receive a second single-ended input clock signal, and input buffer circuitry coupled to the first and second clock inputs. The input buffer circuitry is adapted to select an input clock signal among the first single-ended input clock signal, the second single-ended input clock signal, and a differential input clock signal derived from the first and second single-ended input clock signals. A phase-locked loop (PLL) is adapted to receive an input clock signal selected by the input buffer circuitry and to generate a PLL clock signal based on the selected input clock signal. A clock output provides an output clock signal based on the PLL clock signal.

In one embodiment of the invention, a clock distribution (CD) chip has one or more input pins, input buffer circuitry, clock generation and distribution circuitry, fanout circuitry, one or more output pins, a feedback pin, and feedback buffer circuitry. Based on single-ended or differential input clock signals applied to the input pins, the CD chip can be programmably configured to generate zero, one, or more zero-delay (ZD) output clock signals and zero, one, or more non-zero-delay (NZD) output clock signals for simultaneous presentation at the output pins.

Clock distribution chip for generating both zero-delay and non-zero-delay clock signals

Improved common mode feedback techniques are provided for charge pumps, phase-locked loops (PLLs), and other circuits. For example, in accordance with an embodiment of the present invention, a circuit includes a loop filter having first and second loop filter nodes. An amplifier is provided having first and second differential inputs respectively coupled to the first and second loop filter nodes. A first current source is coupled to the first loop filter node and a second current source is coupled to the second loop filter node. The first and second current sources continuously adjust a common mode voltage of the loop filter nodes.

Phase-locked loop systems and methods

In accordance with one or more embodiments of the present invention, a system includes a phase-locked loop circuit that receives a reference signal and a feedback signal and provides an output signal. A control circuit also receives the reference signal and the feedback signal and provides a correction current for the phase-locked loop circuit to reduce a phase error of the output signal.

Systems and methods for reducing static phase error

Systems and methods are disclosed to provide clock generation. In accordance with one embodiment, a clock generator chip is provided that is configurable and in-system programmable and includes a flexible skew control architecture. The clock generator chip may also provide programmable input circuits, programmable output circuits, and permit a JTAG boundary scan.

Growing community of inventors

Bristol, United Kingdom

Harald Weller