Methods, systems, and devices for delay adjustment circuits are described. Amplifiers (e.g., differential amplifiers) may act like variable capacitors (e.g., due to the Miller-effect) to control delays of signals between buffer (e.g., re-driver) stages. The gains of the amplifiers may be adjusted by adjusting the currents through the amplifiers, which may change the apparent capacitances seen by the signal line (due to the Miller-effect). The capacitance of each amplifier may be the intrinsic capacitance of input transistors that make up the amplifier, or may be a discrete capacitor. In some examples, two differential stages may be inserted on a four-phase clocking system (e.g., one on 0 and 180 phases, the other on 90 and 270 phases), and may be controlled differentially to control phase-to-phase delay.

Methods, systems, and devices for delay adjustment circuits are described. Amplifiers (e.g., differential amplifiers) may act like variable capacitors (e.g., due to the Miller-effect) to control delays of signals between buffer (e.g., re-driver) stages. The gains of the amplifiers may be adjusted by adjusting the currents through the amplifiers, which may change the apparent capacitances seen by the signal line (due to the Miller-effect). The capacitance of each amplifier may be the intrinsic capacitance of input transistors that make up the amplifier, or may be a discrete capacitor. In some examples, two differential stages may be inserted on a four-phase clocking system (e.g., one on 0 and 180 phases, the other on 90 and 270 phases), and may be controlled differentially to control phase-to-phase delay.

The present description concerns a comparator (1) of a first voltage (V+) and of a second voltage (V−), comprising first (100) and second (102) branches each comprising a same succession of alternated first (106) and second (108) gates in series between a node (104) and an output (1002; 1022) of the branch (100; 102), wherein: each branch starts with a first gate (106), each gate (106; 108) has a second node (114) receiving a bias voltage, the second node (114) of each first gate (106) of the first branch (100) and of each second gate (108) of the second branch (102) receives the first voltage (V+), the second node of the other gates receiving the second voltage (V−), and an order of arrival of the edges on the outputs (1002; 1022) of the branches determines a result of a comparison.

The present description concerns a comparator (1) of a first voltage (V+) and of a second voltage (V−), comprising first (100) and second (102) branches each comprising a same succession of alternated first (106) and second (108) gates in series between a node (104) and an output (1002; 1022) of the branch (100; 102), wherein: each branch starts with a first gate (106), each gate (106; 108) has a second node (114) receiving a bias voltage, the second node (114) of each first gate (106) of the first branch (100) and of each second gate (108) of the second branch (102) receives the first voltage (V+), the second node of the other gates receiving the second voltage (V−), and an order of arrival of the edges on the outputs (1002; 1022) of the branches determines a result of a comparison.

Methods and systems are described for generating multiple phases of a local clock at a controllable variable frequency, using loop-connected strings of active circuit elements. A specific embodiment incorporates a loop of four active circuit elements, each element providing true and complement outputs that are cross-coupled to maintain a fixed phase relationship, and feed-forward connections at each loop node to facilitate high frequency operation. A particular physical layout is described that maximizes operating frequency and minimizes clock pertubations caused by unbalanced or asymmetric signal paths and parasitic node capacitances.

Methods and systems are described for generating multiple phases of a local clock at a controllable variable frequency, using loop-connected strings of active circuit elements. A specific embodiment incorporates a loop of four active circuit elements, each element providing true and complement outputs that are cross-coupled to maintain a fixed phase relationship, and feed-forward connections at each loop node to facilitate high frequency operation. A particular physical layout is described that maximizes operating frequency and minimizes clock pertubations caused by unbalanced or asymmetric signal paths and parasitic node capacitances.

Methods, systems, and devices for delay adjustment circuits are described. Amplifiers (e.g., differential amplifiers) may act like variable capacitors (e.g., due to the Miller-effect) to control delays of signals between buffer (e.g., re-driver) stages. The gains of the amplifiers may be adjusted by adjusting the currents through the amplifiers, which may change the apparent capacitances seen by the signal line (due to the Miller-effect). The capacitance of each amplifier may be the intrinsic capacitance of input transistors that make up the amplifier, or may be a discrete capacitor. In some examples, two differential stages may be inserted on a four-phase clocking system (e.g., one on 0 and 180 phases, the other on 90 and 270 phases), and may be controlled differentially to control phase-to-phase delay.

Methods and systems are described for generating multiple phases of a local clock at a controllable variable frequency, using loop-connected strings of active circuit elements. A specific embodiment incorporates a loop of four active circuit elements, each element providing true and complement outputs that are cross-coupled to maintain a fixed phase relationship, and feed-forward connections at each loop node to facilitate high frequency operation. A particular physical layout is described that maximizes operating frequency and minimizes clock pertubations caused by unbalanced or asymmetric signal paths and parasitic node capacitances.

A phase interpolating (PI) system includes: a PI stage configured to receive first and second clock signals and a multi-bit weighting signal, and generate an interpolated clock signal; and an amplifying stage configured to receive and amplify the interpolated clock signal, the amplifying stage including a capacitive component. The capacitive component is tunable to exhibit non-zero capacitances. The capacitive component has a Miller effect configuration resulting in a reduced footprint of the amplifying stage.

A phase interpolating (PI) system includes: a phase-interpolating (PI) stage configured to receive first and second clock signals and a multi-bit weighting signal, and generate an interpolated clock signal, the PI stage being further configured to avoid a pull-up/pull-down (PUPD) short-circuit situation by using the multi-bit weighting signal and a logical inverse thereof (multi-bit weighting_bar signal); and an amplifying stage configured to receive and amplify the interpolated clock signal, the amplifying stage including a capacitive component; the capacitive component being tunable; and the capacitive component having a Miller effect configuration resulting in a reduced footprint of the amplifying stage.