Transistor Threshold Compensation for PVT-Stable Low-Voltage Circuits
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Solution Overview
Problem
Existing compensation devices for PVT variations in analog and/or digital circuits face significant challenges in maintaining stable power dissipation and optimal performance, especially when operating in sub- or near-threshold regions, due to large variability in reference voltage and increased sensitivity to process, voltage, and temperature variations.
Innovation Solution
A compensation device that adjusts the threshold voltage of a transistor by controlling the current flowing between its terminals, using a current generation module and compensation module to adaptively alter the voltage based on PVT variations, thereby minimizing the influence of these variations without the need for monitoring structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transistors are operated in sub-threshold or near-threshold region to reduce power consumption, then dynamic power dissipation is reduced, but sensitivity to PVT variations increases
Solution Approach 1:
The patent changes the operating parameters of transistors by applying adaptive body bias voltages to adjust threshold voltages dynamically. This allows the circuit to operate in sub-threshold or near-threshold regions while compensating for PVT variations through real-time parameter adjustment, thereby reducing power consumption without sacrificing reliability
Solution Approach 2:
The patent implements feedback mechanisms that monitor PVT variations and adjust body bias voltages accordingly. The compensation device continuously adapts the threshold voltages of transistors based on detected variations, creating a closed-loop system that maintains optimal performance despite operating in low-power sub-threshold or near-threshold regions
2Reliability
If reference voltage is generated using bandgap circuit in super-Vth region, then PVT-insensitive constant voltage output is achieved, but voltage headroom is increased
Solution Approach 1:
The patent changes the voltage headroom parameter by operating the bandgap circuit and compensation device at lower voltages. By using adaptive body biasing to maintain transistor threshold voltages, the system achieves PVT-insensitive reference voltage generation with reduced voltage headroom, enabling more efficient power consumption
3Measurement precision
If compensation device monitors PVT variations individually, then precise compensation is achieved, but device complexity increases
Solution Approach 1:
The patent merges the monitoring and compensation functions into a unified compensation device that simultaneously detects PVT variations and applies corrective body bias voltages. By combining these functions and using the fourth terminal for direct threshold voltage control, the system achieves precise compensation without requiring separate monitoring structures for each PVT parameter
4Loss of energy
If supply voltage is reduced to save power, then dynamic power consumption is reduced, but circuit speed performance deteriorates
Solution Approach 1:
The patent changes the threshold voltage parameter of transistors through adaptive body biasing, allowing the circuit to maintain adequate transistor switching speeds even at reduced supply voltages. By dynamically adjusting threshold voltages to compensate for process and temperature variations, the system achieves low power consumption without severe speed degradation
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
This approach reduces power dissipation variability, optimizes dynamic power consumption, and allows for lower supply voltages, eliminating deterministic PVT variations while maintaining circuit speed and reducing leakage currents, thus enhancing the efficiency and reliability of analog and digital circuits.
Implementation Method 1
the transistor is configured to be in saturation region... the difference between the voltage at the second terminal and the voltage at the third terminal is known or has a predetermined value
Data Source
AI summary
The present invention concerns a compensation device for compensating PVT variations of an analog and/or digital circuit, said compensation device comprising:- a transistor comprising - a first terminal (D), - a second terminal (G), - a third terminal (S), and - a fourth terminal (B, G', G'') allowing to modify a threshold voltage(Vth) of the transistor, wherein the transistor is configured to be in saturation region, wherein the voltage at the third terminal (S) has a predetermined value, wherein the difference between the voltage at the second terminal (G) and the voltage at the third terminal (S) has a predetermined value, - a current generation module, configured to generate a current of a predetermined value, - a compensation module, configured to force this current to flow between the first terminal (D) and the third terminal (S) by adjusting the voltage of the fourth terminal (B, G', G'').