Adjustable Delay Line Voltage Control for Critical Path Accuracy
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Solution Overview
Problem
Typical closed-loop voltage control systems for integrated circuits do not accurately emulate the critical path, leading to inaccurate delay measurements and suboptimal power consumption, as they use delay lines with uniform delay properties that do not account for variations in process, voltage, and temperature (PVT) across different circuit elements.
Innovation Solution
An adjustable delay line with distinct delay elements, emulating the delay properties of physical elements like gates and wires, is used to accurately estimate the critical path delay, allowing for precise adjustment of the supply voltage to maintain target performance while minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a delay line with uniform delay properties is used to emulate the critical path, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision of delay time deteriorates because it cannot accurately account for PVT variations across different circuit elements
Solution Approach 1:
The delay line is segmented into multiple distinct delay elements, each emulating different physical elements (gates, wires) with different delay properties. This segmentation allows the system to accurately model the critical path's heterogeneous delay characteristics while maintaining a manageable structure through modular organization of delay elements.
Solution Approach 2:
Different delay elements within the delay line are assigned different delay properties to match the local characteristics of physical elements in the critical path. This local quality approach ensures that each segment of the delay line accurately reflects the PVT variations specific to the circuit elements it emulates, thereby improving overall measurement precision.
2Use of energy by moving object
If the supply voltage is reduced to minimize power consumption, then the use of energy is improved, but the reliability of proper operation deteriorates if the voltage is too low to maintain target performance level
Solution Approach 1:
The system employs feedback through the delay line measurement mechanism to continuously monitor the critical path delay and adjust the supply voltage accordingly. This feedback loop ensures that the voltage is reduced only to the extent that maintains target performance level, preventing operation below the reliability threshold while maximizing energy savings.
Solution Approach 2:
The supply voltage is dynamically changed based on the measured delay time from the delay line. By adjusting this critical parameter in response to real-time measurements, the system optimizes power consumption while ensuring that voltage remains sufficient to maintain proper circuit operation and target performance level.
3Measurement precision
If delay elements with different delay properties are used to accurately emulate the critical path, then the measurement precision is improved, but the device complexity increases due to the need for multiple distinct delay elements with different characteristics
Solution Approach 1:
The delay line is designed as a universal emulation structure that can represent multiple types of physical elements (gates, wires, interconnects) through its distinct delay elements. This multi-functionality allows a single delay line device to accurately model various critical path configurations without requiring separate measurement circuits for each element type, thereby improving ease of manufacture.
Data Source
AI summary
Controlling a power supply which supplies a voltage to target circuit of an integrated circuit. An adjustable delay line powered by the supply voltage is co-located on the IC with the target circuit. The adjustable delay line is subjected to substantially the same operating conditions as the target circuit. A control unit measures a delay time of the adjustable delay line. Based on the measured delay time, the control unit outputs a control signal by which the power supply adjusts the supply voltage. The adjustable delay line comprises multiple distinct delay elements, each with delay properties and responsivity to changes in operating conditions. Each delay element emulates delay properties of physical elements (e.g., gates and wires) in the target circuit. In this manner, power consumption may be reduced, while still maintaining proper operation of the target circuit.