Delay circuits matching delays of synchronous circuits

Abstract

Delay circuits capable of providing delays closely matching propagation delays of synchronous circuits are described. In one design, an apparatus includes a synchronous circuit and a delay circuit. The synchronous circuit includes a forward path from a data input to a data output. The synchronous circuit receives input data and provides output data with a propagation delay. The delay circuit receives an input signal and provides a delayed input signal having a delay matching the propagation delay of the synchronous circuit. The delay circuit includes at least two logic gates in the forward path of the synchronous circuit. The synchronous and delay circuits may be implemented based on the same or similar circuit architecture. The delay circuit may be based on a replica of the synchronous circuit, with the replica having feedback loops broken and clock input coupled to appropriate logic value to always enable the delay circuit.

Description

technical field [0001] The present invention relates generally to electronic circuits and, more particularly, to delay circuits. Background technique [0002] A synchronous circuit is a circuit whose operation may be controlled by a control signal such as a clock signal, a strobe signal, an enable signal, and the like. A synchronous circuit is in contrast to a combinational circuit that changes its output when its input changes. Some examples of synchronous circuits include latches and flip-flops, which can operate in a synchronous manner based on a common clock signal. [0003] Synchronous circuits such as latches and flip-flops are widely used in various digital circuit designs. A latch is a circuit that can store one bit of information and that can be controlled by a control signal such as a clock signal. A flip-flop is a circuit that stores one bit of information and captures incoming data based on a clock edge. The main difference between a latch and a flip-flop is ...

AI Technical Summary

Problems solved by technology

The propagation delay can be attributed to the logic gates used to implement the synchronous circuit and can vary widely due to variations in integrated circuit (IC) process, supply voltage, and temperature (PVT)

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