Power-Domain Delay Circuit for Synchronized Logic Transitions
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Solution Overview
Problem
Integrated circuits with multiple power domains face challenges in maintaining synchronized signal propagation due to varying voltage levels across different power supply nodes, leading to inconsistent delay times for logic signals.
Innovation Solution
A voltage-controlled delay circuit that adjusts delay times based on the voltage level of a secondary power supply node, allowing for synchronized signal propagation across power domains without requiring a level shifter, by using inverting circuits that sink or source current based on the voltage level to control the delay of logic signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If different voltage levels are used in different power domains to optimize power consumption, then power efficiency is improved, but signal propagation delay becomes inconsistent across domains
Solution Approach 1:
The delay element uses a controllable current source that dynamically adjusts the delay time based on the voltage level of the second power domain. The current source is controlled by the voltage level signal to provide variable delay compensation, allowing the system to adapt to different voltage conditions while maintaining synchronized signal propagation across power domains with different voltage levels.
2Reliability
If delay elements are added to synchronize signals across power domains, then signal propagation consistency is improved, but device complexity increases
Solution Approach 1:
The delay element is designed to receive both a logic signal and a voltage level signal from the second power domain, using the voltage level information to control the delay amount. This multi-functional approach allows a single circuit element to perform both signal delay and voltage-level-dependent adaptation, reducing the need for separate control circuits and minimizing overall device complexity while ensuring synchronized propagation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures consistent delay times for logic signals across different power domains, even when voltage levels differ, preventing improper operation and potential issues like crowbar currents, while allowing for efficient power management and reduced power consumption.
Implementation Method 1
The first circuit may be configured to, based on a voltage level of a logic signal, sink a current from an intermediate circuit node. A value of the current may be based upon a voltage level of the second different power supply signal.
Implementation Method 2
The second circuit coupled to the first power supply signal. The second circuit may be configured to generate an output signal based upon a voltage level of the intermediate circuit node.
Data Source
AI summary
An apparatus for delaying a signal transition is disclosed. The apparatus includes a first circuit coupled to a first power supply signal and a second, different power supply signal. The first circuit may be configured to, based on a voltage level of a logic signal, sink a current from an intermediate circuit node. A value of the current may be based upon a voltage level of the second different power supply signal. The apparatus also includes a second circuit coupled to the first power supply signal. The second circuit may be configured to generate an output signal based upon a voltage level of the intermediate circuit node. An amount of time between a transition of the logic signal and a corresponding transition of the output signal may be based on an amount of the current.