Auto-Tuned Pseudo Resistor for PVT Drift Compensation
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Solution Overview
Problem
Pseudo resistors are sensitive to process, voltage, and temperature (PVT) variations, leading to distortion in signal processing and inaccurate frequency response in amplifier applications due to changes in resistance, affecting signal gain and accuracy.
Innovation Solution
A pseudo resistor with an auto-tune function that calibrates its resistance based on the output signal of an amplifier or other electrical components, using a configuration of transistors and an adder to generate a bias voltage for dynamic adjustment, and includes a calibration circuit to detect and compensate for voltage drifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If pseudo resistor is used to generate resistance for circuit structures, then area occupation is reduced and power consumption is lowered, but resistance value becomes sensitive to PVT variation causing signal processing distortion
Solution Approach 1:
The patent implements a feedback mechanism where the output signal of the amplifier is fed back to the calibration circuit, which then adjusts the bias voltage of the pseudo resistor to compensate for resistance changes. This closed-loop feedback system continuously monitors and corrects PVT variations, maintaining stable resistance values while preserving the area and power consumption benefits of pseudo resistors.
Solution Approach 2:
The patent dynamically changes the bias voltage parameter applied to the pseudo resistor through the calibration circuit. By adjusting this voltage parameter in response to detected output signal variations, the system compensates for PVT-induced resistance changes, maintaining reliable performance without increasing physical area or power consumption.
2Device complexity
If pseudo resistor resistance changes due to PVT variation, then device complexity remains low, but manufacturing precision and signal processing accuracy deteriorate
Solution Approach 1:
The calibration circuit performs self-adjustment by automatically detecting output signal variations and correcting the pseudo resistor's resistance through bias voltage modulation. This self-service mechanism compensates for manufacturing variations and PVT effects without requiring external calibration equipment or complex manual adjustment procedures, maintaining both low device complexity and high precision.
3Reliability
If auto-tune function is added to calibrate pseudo resistor resistance, then resistance stability improves, but device complexity increases
Solution Approach 1:
The patent merges the calibration function with the existing amplifier output stage by using the amplifier's output signal directly for calibration purposes. The calibration circuit is integrated into the signal path, combining multiple functions (amplification, calibration, and compensation) into a unified structure that minimizes additional complexity while achieving improved resistance stability.
Data Source
AI summary
Pseudo resistor having an auto-tune function automatically calibrates resistance of the pseudo resistor and compensates for DC drift based on an output signal of an electrical circuit to which the pseudo resistor is coupled, as to mitigate signal phenomenon in the output signal caused by PVT variation. The pseudo resistor includes first transistor, second transistor, and adder. The first terminal of the second transistor is coupled to the first terminal of the first transistor and forms a first common node. The control terminal of the first transistor is coupled to the control terminal of the second transistor and forms second common node. The adder is coupled between the first and second common nodes and configured to receive adjustment voltage for generating a bias voltage for controlling the first and second transistors, where the adjustment voltage corresponds to the output signal coupled to the second terminal of the second transistor.