Repeater Circuit Reconfiguration for Long Interconnect RC Delay
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Solution Overview
Problem
Long signal interconnects in integrated circuits (ICs) lead to excessive resistance and capacitance, causing signal transition delays and potential circuit damage due to crowbar currents, which existing repeater circuits may not adequately address.
Innovation Solution
A method to convert a dynamic repeater circuit into a static repeater circuit by disconnecting the feedback path and electrically shorting the gate terminals of transistors in the second stage, reconfiguring selection devices to enable the repeater circuit to function as a static repeater, reducing power consumption and sensitivity to resistance and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If dynamic repeater circuits are used to overcome resistance and capacitance effects in long interconnects, then signal transition speed is improved, but power consumption increases due to continuous dynamic operation of output devices
Solution Approach 1:
The circuit employs dynamic output devices (P3, N5) that change state within a given cycle, turning on and off responsive to input transitions. This dynamic operation allows the output devices to provide drive only when needed, reducing continuous power consumption while maintaining fast signal transition capability.
Solution Approach 2:
The output devices operate periodically rather than continuously, activating only during signal transitions and remaining inactive during stable states. This periodic action reduces average power consumption while ensuring signal integrity is maintained during critical transition periods.
2Loss of time
If dynamic repeater circuits are used to reduce propagation delay, then signal transition time is improved, but sensitivity to resistance and capacitance increases leading to potential circuit damage
Solution Approach 1:
The circuit converts the potentially harmful crowbar current effect into a beneficial mechanism by using it to quickly charge or discharge the interconnect capacitance during transitions. The dynamic output devices leverage the RC time constant to achieve fast transitions while the feedback mechanism prevents sustained harmful current flow.
Solution Approach 2:
The feedback path with inverters I3-I5 provides regenerative action that reinforces the output transition and then terminates it when complete. This feedback mechanism ensures that the output devices remain active long enough to overcome RC effects but turn off promptly to prevent circuit damage from excessive current.
3Reliability
If complex dynamic repeater circuits are implemented to overcome long interconnect effects, then signal integrity is improved, but device complexity increases
Solution Approach 1:
The repeater circuit is segmented into distinct functional blocks: input stage (inverters I1-I2), output stage (P3, N5), and feedback path (inverters I3-I5). This segmentation allows each block to be optimized independently for its specific function while maintaining overall signal integrity through coordinated operation.
Data Source
AI summary
A method for converting a repeater circuit from a dynamic repeater circuit to a static repeater circuit. The method includes disconnecting a feedback path coupled to a first stage of the dynamic repeater circuit and electrically shorting gate terminals of first and second transistors of a second stage to each other, wherein the transistors of the second stage are configured to drive an output signal on an output node. Disconnecting the feedback path and electrically shorting the gate terminals is performed by reconfiguring a plurality of selection devices in the repeater circuit from a first configuration to a second configuration. The repeater circuit includes at least one keeper configured to provide an output signal on the output node.