Ratiometric Sensor Circuit With Analog Gain Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ratiometric sensor circuits are either expensive and slow when realized using digital signal processing or lack complete ratiometric reaction with fixed sensitivity, making them unsuitable for low-cost microprocessors.
Innovation Solution
A sensor circuit design utilizing a control circuit to adjust a constant first signal to a ratiometric second signal through a first amplifier, with an adjustable second amplifier for the sensor signal, achieving a ratiometric gain by linearly coupling it to the supply signal, and employing replica amplifiers to ensure identical behavior under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital signal processing is used to achieve fully ratiometric output, then measurement accuracy is improved, but cost and processing time increase
Solution Approach 1:
The patent replaces complex digital signal processing systems with an analog circuit implementation. By using operational amplifiers configured in a specific topology where one amplifier processes the sensor signal and another processes a reference signal, the system achieves ratiometric output through analog computation rather than digital processing. This substitution maintains measurement accuracy while significantly reducing circuit complexity and cost.
2Measurement precision
If digitally controlled gain amplifiers are used, then ratiometric behavior is improved, but cost increases
Solution Approach 1:
The patent replaces digitally controlled gain amplifiers with standard operational amplifiers operating in analog mode. The ratiometric behavior is achieved through the circuit topology itself, where the output voltage represents a ratio of two input signals processed by analog amplifiers. This eliminates the need for expensive digital control circuits while maintaining full ratiometric functionality.
Solution Approach 2:
The patent changes the operating parameters of standard operational amplifiers to achieve variable gain behavior. By configuring the amplifiers with specific feedback networks and operating points, the circuit achieves gain that is controlled by the ratio of input signals rather than by digital control. This allows standard, low-cost amplifiers to perform the function of expensive digitally controlled amplifiers.
3Ease of manufacture
If fixed sensitivity sensors are used, then manufacturing simplicity is improved, but adaptability to supply voltage fluctuations deteriorates
Solution Approach 1:
The patent makes the sensor circuit universally adaptable to different supply voltage conditions by introducing a reference signal that tracks the supply voltage. The circuit processes both the sensor signal and the reference signal through matched amplifier paths, allowing the output to automatically compensate for supply variations. This multi-functional approach allows the same simple circuit to work across different operating conditions without requiring complex adaptive control.
Data Source
AI summary
The present disclosure relates to a sensor circuit including a control circuit configured to control a constant first signal to a ratiometric second signal using a first amplifier adjustable by an actuating signal, and an adjustable second amplifier for a sensor signal, the gain of which is adjustable by the actuating signal.