Bandgap Reference Circuit Stress Compensation
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Solution Overview
Problem
Bandgap reference circuits face instability and inaccuracy due to mechanical and environmental stresses, such as packaging and temperature variations, which existing solutions like open cavity hermetic packages or stress gauges cannot consistently compensate for.
Innovation Solution
A system incorporating a calibration circuit, multiplexer, and processing unit that uses calibrated pnp and npn transistors to generate stress-compensated bandgap voltage references by calculating a gain correction factor based on temperature-dependent values, adjusting the output signal to correct for stress-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional bandgap reference circuits are used, then temperature independence is achieved, but stress-induced voltage instability occurs
Solution Approach 1:
The patent implements a feedback mechanism where the bandgap reference voltage is continuously monitored and compared against expected values. Correction signals are generated based on detected deviations caused by mechanical stress, and these signals are fed back to adjust the reference voltage output, thereby maintaining stability despite stress-induced variations
Solution Approach 2:
The patent changes the operational parameters of the bandgap reference circuit by introducing stress compensation techniques. This includes modifying the voltage levels and current densities in response to detected stress conditions, allowing the circuit to adapt its parameters to maintain accurate reference voltage output under varying mechanical stress
2Reliability
If open cavity hermetic packages are used, then stress sensitivity is reduced, but cost increases
Solution Approach 1:
The patent enables the voltage reference circuit to self-compensate for stress effects through integrated monitoring and correction mechanisms. The system automatically detects stress-induced variations and applies corrections without requiring external calibration or specialized packaging, making standard packaging sufficient and reducing manufacturing costs
Solution Approach 2:
The patent replaces mechanical stress protection methods (such as hermetic packaging) with an electronic compensation system. Instead of using mechanical means to isolate the circuit from stress, the invention uses electronic sensing and correction circuits to compensate for stress effects, thereby eliminating the need for expensive specialized packaging
3Reliability
If stress gauge using MOS device is implemented, then stress compensation is attempted, but consistent stress response is not achieved
Solution Approach 1:
The patent uses bipolar transistors with matched characteristics and identical geometric structures to ensure uniform stress response. By employing homogeneous device structures throughout the compensation circuitry, the system achieves consistent and predictable stress responses that enable accurate compensation without the variability encountered with MOS-based approaches
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
The system effectively compensates for stress-induced inaccuracies in voltage references, ensuring stability and accuracy of analog-to-digital converter outputs, even under varying environmental conditions.
Implementation Method 1
generates a first calibrated pnp voltage based on a base-emitter voltage of one or more pnp transistors and a second calibrated npn voltage based on a base-emitter voltage of one or more npn transistors
Data Source
AI summary
In a system and method for correcting a stress-impaired signal in a circuit, a calibration circuit produces a first calibrated voltage based on a base-emitter voltage of one or more pnp transistors, a second calibrated voltage based on a base-emitter voltage of one or more npn transistors, and a voltage proportional to absolute temperature. A set of reference values are generated based on these voltages. A gain correction factor is calculated based on a function of the set of reference values and a set of temperature-dependent values, and the stress-impaired signal is corrected based on the gain correction factor.