Low-Swing Dynamic Circuit With Level-Detected Precharge Cutoff
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Solution Overview
Problem
Dynamic circuits face high power consumption and leakage issues due to their faster operation and higher leakage currents, leading to false logic detections and increased power dissipation.
Innovation Solution
A dynamic circuit design that includes a level detector circuit to control charging based on a logic high reference voltage, a second charge circuit to compensate for leakage currents, and pull-down logic circuitry with adjustable resistance, which helps maintain the voltage at the dynamic node and reduce power consumption by disconnecting the supply when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic circuits operate with full supply voltage swings, then logic detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the reference voltage level used for logic detection. Instead of using a fixed reference voltage, the circuit selectively switches between a first reference voltage (closer to VDD) and a second reference voltage (closer to VSS) based on the evaluation phase state. This allows the circuit to optimize between detection reliability and power consumption by using appropriate reference levels for different operating conditions.
Solution Approach 2:
The patent implements dynamics by making the reference voltage selection dynamic rather than static. The reference voltage changes dynamically during operation based on whether the evaluation phase is active or inactive. This dynamic adaptation allows the circuit to respond to changing operational requirements and optimize performance characteristics in real-time.
2Speed
If dynamic circuits use pre-charge intervals, then operation speed is improved, but leakage current increases
Solution Approach 1:
The patent applies preliminary action by performing the pre-charge operation during a dedicated pre-charge interval before the evaluation phase. The dynamic node is pre-charged to a predetermined voltage level in advance, ensuring that the node is ready for rapid evaluation when the evaluation phase begins. This preliminary charging action enables fast operation while the leakage current issue is managed separately through reference voltage selection.
Solution Approach 2:
The patent implements feedback by using the output of the dynamic circuit to control the selection of reference voltage. The circuit monitors the evaluation phase results and uses this feedback to determine whether to use the first or second reference voltage for subsequent operations. This feedback mechanism allows the circuit to adapt to actual operating conditions and minimize leakage current while maintaining operation speed.
3Measurement precision
If dynamic circuits maintain high voltage levels, then logic high detection accuracy is improved, but power dissipation increases
Solution Approach 1:
The patent applies parameter changes by varying the reference voltage parameter based on operational needs. When logic high detection accuracy is critical, the circuit uses the first reference voltage (closer to VDD) which provides better discrimination for high logic levels. When power dissipation is the primary concern and logic levels are well-defined, the circuit can use the second reference voltage (closer to VSS), thereby reducing power consumption while maintaining adequate detection accuracy.
Data Source
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AI summary
Embodiments of the present disclosure enable low swing dynamic circuits with reduced dynamic power and leakage power. In an embodiment, a level detector circuit monitors the pre-charge voltage level of the dynamic node of a dynamic circuit and discontinues the charging of the dynamic node when the pre-charge voltage exceeds a logic high reference voltage. The logic high reference voltage is selected below a supply voltage of the dynamic circuit, resulting in a low swing dynamic circuit. In another embodiment, the pull-down logic circuitry is disconnected from the dynamic node when the dynamic node voltage falls below a logic low reference voltage, above a ground voltage. In another embodiment, a DC keeper circuit of the dynamic circuit is configured based on the pre-charge level of the dynamic node.