Programmable Active Inductor With Digitally Switched Resistance
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Solution Overview
Problem
Existing active inductor circuits face challenges in maintaining tunable bandwidth and linearity due to process, temperature, and supply variations, requiring large PMOS devices for resistance control.
Innovation Solution
The implementation of a programmable active inductor with a variable resistive circuit that allows selective bypassing of resistors using control signals, enabling digital control of resistance and inductance to achieve tunable bandwidth and improved linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If continuous tuning is used to achieve desired bandwidth, then bandwidth adjustability is improved, but device size becomes prohibitively large
Solution Approach 1:
The continuous tuning mechanism is segmented into discrete resistance steps using multiple switches (S1, S2, S3, S4) that can be independently controlled. This allows the active inductor to achieve bandwidth adjustment through digital control signals rather than continuous analog control, significantly reducing the required PMOS device size while maintaining adaptability.
Solution Approach 2:
The invention dynamically adjusts the resistance value by selectively enabling or disabling switches based on digital control signals. This dynamic switching mechanism allows the active inductor to adapt its bandwidth characteristics in response to varying operational requirements without requiring large oversized devices for maximum coverage.
2Ease of manufacture
If fixed resistance values are used for fabrication, then manufacturing simplicity is improved, but bandwidth stability deteriorates due to process and temperature variations
Solution Approach 1:
Instead of relying on fixed resistance values that are sensitive to process and temperature variations, the invention implements a dynamic resistance adjustment mechanism. Multiple switches can selectively connect different resistance paths, allowing the system to compensate for environmental variations and maintain stable bandwidth performance throughout the operational range.
Solution Approach 2:
The invention changes the resistance parameter dynamically through digital control signals that enable or disable specific switches. This allows the resistance value to be adjusted in discrete steps to maintain optimal bandwidth performance across varying process conditions, temperature ranges, and supply voltages, thereby improving reliability without sacrificing manufacturing simplicity.
Data Source
AI summary
Methods and apparatus are provided for programmable active inductance. The disclosed active inductor devices provide a tunable bandwidth with improved linearity. The disclosed active inductors have a variable frequency response corresponding to a variable inductance of the active inductor. The active inductor comprises a variable resistive circuit having an effective resistance, wherein the variable resistive circuit is comprised of at least one resistor that can be selectively bypassed in the variable resistive circuit to vary the effective resistive. The active inductor has an inductance that can be varied by varying the effective resistance.