Adaptive Bias Refresh Circuit for Low-Power Voltage Accuracy
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Solution Overview
Problem
Integrated circuits (ICs) face high power consumption due to active bias generators maintaining tight voltage and current tolerances, even in low power states, necessitating extensive lab characterization for conservative refresh rates that are higher than needed, delaying time to market and increasing current consumption.
Innovation Solution
An adaptive refresh rate generator (ARRG) with replica sampler circuits and comparators dynamically controls the refresh rate based on process, voltage, and temperature variations, using leakage current to adjust the frequency of bias reference refreshing, reducing power consumption and silicon characterization efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conservative refresh rate is chosen to cover worst corner cases, then reliability is improved, but power consumption increases and time to market is delayed
Solution Approach 1:
The patent implements a dynamic refresh rate adjustment mechanism that adapts the refresh rate based on actual operating conditions (temperature, process variations) rather than using a fixed conservative rate. The system monitors bias voltage drift and adjusts refresh timing accordingly, allowing lower refresh rates when conditions are stable and higher rates when drift is detected, thus reducing overall power consumption while maintaining reliability.
Solution Approach 2:
The system changes the refresh rate parameter dynamically based on measured drift characteristics and environmental conditions. By adjusting this key parameter according to actual needs rather than maintaining a fixed conservative value, the system achieves both reliability and power efficiency.
2Manufacturing precision
If extensive lab characterization is performed to optimize duty cycle, then manufacturing precision is improved, but time to market increases and device complexity increases
Solution Approach 1:
The system performs self-characterization by monitoring its own bias voltage drift over time and using this information to automatically optimize refresh rates. The on-chip drift detector and adaptive controller enable the device to learn and adapt to its specific process corner and environmental conditions without requiring extensive external lab characterization, thus reducing time to market while achieving optimal performance.
Solution Approach 2:
The patent implements a feedback mechanism where the drift detector continuously monitors bias voltage changes and feeds this information back to the refresh rate controller. This closed-loop system automatically optimizes operation based on real-time measurements, eliminating the need for extensive pre-characterization and enabling the device to self-tune to optimal performance.
3Measurement precision
If a higher refresh rate is used, then bias voltage accuracy is maintained, but current consumption increases
Solution Approach 1:
The system uses periodic refresh actions triggered by detected drift rather than continuous high-rate refreshing. The refresh operation is performed periodically at the minimum necessary rate to maintain accuracy, with the period dynamically adjusted based on actual drift measurements. This eliminates unnecessary current consumption during intervals when bias voltage remains within tolerance.
4Stability of the object's composition
If the bias generator is kept active continuously, then bias voltage stability is improved, but power consumption increases
Solution Approach 1:
The bias generator operates in a sampled mode with periodic refresh cycles rather than continuously active. The system determines optimal refresh intervals based on drift measurements and environmental conditions, keeping the bias generator dormant during stable periods and activating only when refresh is needed to maintain stability, thus dramatically reducing power consumption while preserving voltage stability.
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 ARRG ensures accurate bias voltage maintenance with reduced power consumption by adapting the refresh rate to match temperature and process variations, minimizing unnecessary current draw and simplifying scheduling circuits.
Implementation Method 1
a first comparator coupled to the first replica sampler circuit, the first comparator having a first input terminal to receive the sampled first voltage and a second input terminal to receive the reference voltage, where the first comparator is to output a first signal having a first value when the sampled first voltage departs from the reference voltage by at least a threshold amount
Implementation Method 2
a first capacitor coupled to the first switch circuit, the first capacitor to be charged by the first voltage
Implementation Method 3
a first switch circuit, when enabled, to pass the first voltage
Data Source
AI summary
In one embodiment, an apparatus includes: a replica sampler circuit to sample a first voltage that is based on a reference voltage, the replica sampler circuit to at least approximate a non-linearity of a bias generator. The replica sampler circuit may include: a switch circuit, when enabled, to pass the first voltage; and a capacitor coupled to the switch circuit, the capacitor to be charged by the first voltage. The apparatus also may include a comparator coupled to the replica sampler circuit, the comparator having a first input terminal to receive the sampled first voltage and a second input terminal to receive the reference voltage, where the comparator is to output a first signal having a first value when the sampled first voltage departs from the reference voltage by at least a threshold amount, to cause a refresh of at least a portion of the bias generator.