Reduction of propagation delay dependence on supply voltage in a digital circuit

摘要

In one embodiment, a digital circuit element has a propagation delay that is substantially constant over a range of supply voltages applied to the digital circuit element. In another embodiment, a digital circuit element may include an input node, an output node, and at least one gate coupling the input node and the output node. A plurality of possible voltage transition curves may be associated with a corresponding change of a first voltage at the input node over time, each voltage transition curve being determined by a corresponding supply voltage and the curves intersecting within a relatively narrow range of voltages. The gate may be operable to change a second voltage at the output node in response to the first voltage reaching a threshold voltage of the gate, and the threshold voltage may be set within the relatively narrow range of voltages in which the voltage transition curves intersect in order to reduce the dependence of the propagation delay on the supply voltage. In yet another embodiment, a digital circuit element having a propagation delay that is substantially constant over a range of supply voltages applied to the digital circuit element includes an input node, an output node, and at least one gate coupling the input node and the output node. The gate is operable to change a first voltage at the output node in response to a second voltage at the input node reaching a threshold voltage of the gate, and the threshold voltage of the gate is set such that a delay separating an initial change in the first voltage from an initial change in the second voltage is substantially constant over a range of supply voltages applied to the digital circuit element.