Controllable Gain Circuit Compensation for Voltage and Temperature Drift
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Solution Overview
Problem
Conventional electronic circuits fail to effectively compensate for second-order errors arising from variations in supply voltage and environmental temperature, which go uncorrected by existing error circuits designed for nominal conditions.
Innovation Solution
A circuit with a controllable gain element, differential shunt circuit, and sensing/control circuitry that detects deviations from nominal operating conditions, recalibrates gain and offset values by shorting differential inputs and updating error values based on sensed voltage and temperature changes, using programmable registers and look-up tables for precise compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional error circuits are used for gain and offset compensation at nominal conditions, then first order systematic errors are corrected, but second order errors from voltage and temperature variations remain uncorrected
Solution Approach 1:
The patent pre-characterizes the controllable gain element at multiple supply voltages and temperatures during manufacturing, storing the measured gain and offset values in lookup tables. During operation, the control circuit automatically selects the appropriate pre-characterized values based on sensed voltage and temperature conditions, eliminating the need for real-time complex calculations and enabling accurate compensation across varying conditions without continuous recalibration
Solution Approach 2:
The patent changes the operating parameters by sensing supply voltage and temperature conditions, then selecting different gain and offset compensation values from lookup tables that correspond to different voltage and temperature ranges. This allows the compensation circuit to adapt to varying operating conditions by switching between pre-determined parameter sets, effectively addressing second-order errors without requiring continuous complex recalibration
2Measurement precision
If continuous recalibration is implemented to maintain accuracy under varying conditions, then compensation precision is maintained, but circuit complexity and power consumption increase
Solution Approach 1:
The patent performs the complex calibration process during manufacturing rather than during operation. The controllable gain element is characterized at multiple supply voltages and temperatures, and the measured values are stored in lookup tables. During normal operation, the control circuit simply senses conditions and retrieves pre-stored values, avoiding the need for continuous complex recalibration operations and reducing both circuit complexity and power consumption
Solution Approach 2:
The patent implements recalibration only when necessary - specifically when supply voltage or temperature changes exceed predetermined thresholds. The control circuit monitors operating conditions and triggers recalibration or lookup table selection only when conditions change significantly, rather than continuously. This periodic action maintains accuracy while minimizing the complexity and power consumption associated with frequent recalibration operations
3Measurement precision
If manual recalibration procedures are used to adjust for voltage and temperature changes, then compensation accuracy can be maintained, but operational efficiency and reliability decrease
Solution Approach 1:
The patent implements an automatic compensation system where the control circuit independently senses supply voltage and temperature conditions, selects appropriate gain and offset values from lookup tables, and applies compensation without requiring manual intervention. The system self-calibrates by monitoring its own operating conditions and automatically adjusting compensation parameters, eliminating the need for manual recalibration procedures and thereby improving operational efficiency and reliability
Solution Approach 2:
The patent incorporates feedback mechanisms where the control circuit continuously monitors supply voltage and temperature conditions, compares them against reference ranges, and automatically adjusts the gain and offset compensation values accordingly. This closed-loop feedback system ensures compensation accuracy is maintained under varying conditions while operating autonomously, eliminating the need for manual recalibration and improving both efficiency and reliability
Data Source
AI summary
Gain offset and voltage offset compensation for a controllable gain element of a circuit is effected in response to a gain offset value and voltage offset value. A current operating condition of the circuit is sensed and compared to a nominal operating condition. If the current operating condition is outside the nominal operating condition by more than a threshold, a calibration operation to set the gain and voltage offset values is performed. The gain offset value is selected as a function of the sensed current operating condition. With respect to the voltage offset, differential input terminals of the controllable gain element are shunted and the output is measured. The measured output value of the controllable gain element is applied as the voltage offset value. The operating conditions at issue may be one or more of supply voltage and temperature.