Active Resistance Generator for SLVS Output Driver Impedance
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Solution Overview
Problem
Conventional methods for correcting output impedance in scalable low voltage signaling (SLVS) require either external resistors, increasing fabrication costs and circuit area, or internal resistors with fabrication deviations that necessitate trimming and additional circuitry.
Innovation Solution
A resistance element generator that uses reference voltages and currents to generate fixed resistance values through transistors acting as active resistors, eliminating the need for internal or external resistors and allowing impedance correction without additional digital correction circuits or trimming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor is mounted outside the chip, then impedance correction is achieved, but fabrication costs and circuit area increase
Solution Approach 1:
The patent extracts the resistor function from external components and integrates it into the chip using transistors configured as active resistors. The resistance is generated dynamically through transistor operation rather than using physical resistor elements, thereby eliminating external SMD resistors and reducing circuit area while maintaining impedance correction capability
Solution Approach 2:
The patent changes the physical state of resistance from passive fixed resistors to active dynamically controllable resistance through transistor operation. By controlling transistor gate voltages and currents, the effective resistance values are adjusted to achieve precise impedance matching without requiring physical resistor components
2Area of stationary object
If a resistor is formed inside the chip, then circuit area is reduced, but fabrication process deviation increases resistance variability
Solution Approach 1:
The patent implements self-calibration through feedback mechanisms where the system automatically adjusts transistor operating parameters to compensate for fabrication variations. The resistance generation circuitry uses feedback from voltage and current references to self-correct resistance values, eliminating the need for external trimming components while maintaining precision despite manufacturing deviations
Solution Approach 2:
The patent incorporates feedback loops that continuously monitor and adjust the resistance values generated by transistors. By using feedback from reference voltages and currents, the system compensates for fabrication process variations and maintains accurate resistance values without requiring external trimming circuitry
3Manufacturing precision
If trimming is performed to correct resistance deviation, then resistance accuracy is improved, but additional circuit area and cost increase
Solution Approach 1:
The patent eliminates the need for external trimming components by implementing self-calibration functionality within the resistance generation circuitry itself. The system uses internal feedback mechanisms to automatically adjust and correct resistance values, thereby achieving precise resistance control without requiring additional trimming circuit area or one-time programmable memory
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 solution reduces chip area and power consumption, eliminates the need for separate digital correction circuits, and simplifies impedance matching in SLVS output drivers, while maintaining accurate impedance correction.
Implementation Method 1
The first resistance value may correspond to the first reference voltage divided by the first reference current. The second resistance value may correspond to the third reference voltage divided by the second reference current.
Data Source
AI summary
A resistance element generator includes a reference current generation unit suitable for receiving a source reference current to generate first and second reference currents, a first resistance generation unit suitable for generating a first resistance value by using a first reference voltage and the first reference current, and outputting a first voltage corresponding to the formed first resistance value, and a second resistance generation unit suitable for generating a second resistance value by using a third reference voltage and the second reference current, and outputting a second voltage corresponding to the formed second resistance value.