Programmable Sensor Interface for Offset Correction and Gain Control
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Solution Overview
Problem
Existing force and pressure sensors with Wheatstone bridge circuits face accuracy issues due to bridge offset voltage, which decreases system accuracy, and there is a need for a highly integrated and versatile sensor interface design for small portable devices with increasing sensor demands.
Innovation Solution
A programmable sensor interface that provides digital offset correction, programmable gain, and sensor biasing using an on-chip voltage regulator, allowing for per-channel calibration and multiplexing of inputs through a variable gain instrumentation amplifier and I2C serial interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bridge offset voltage correction is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple calibration functions (offset correction, gain adjustment, bias control) into a single integrated sensor interface chip. The offset correction circuit, programmable gain amplifier, and voltage regulator are merged into one device, eliminating the need for separate external components and reducing overall system complexity while maintaining high measurement precision.
Solution Approach 2:
The sensor interface chip provides multiple functions including offset correction, programmable gain control, bias voltage generation, and multiplexing capability. This multi-functional design allows a single device to handle various calibration and signal conditioning tasks that would otherwise require multiple separate components, improving precision without proportionally increasing complexity.
2Adaptability or versatility
If multiple sensors are supported on small portable devices, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements per-channel offset correction using individual DACs for each sensor channel, allowing independent calibration of multiple sensors. The multiplexing capability enables different input channels to be selectively activated, supporting multiple sensors while maintaining manageable complexity through organized channel management.
Solution Approach 2:
The sensor interface chip is designed to support multiple differential input channels with unified calibration and control mechanisms. The same offset correction, gain control, and biasing circuits serve multiple channels, enabling small portable devices to integrate various sensor types without requiring separate interface circuits for each sensor.
3Measurement precision
If per-channel calibration is implemented, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent provides individual offset correction DACs for each sensor channel, enabling independent per-channel calibration. Each channel can be calibrated separately to compensate for manufacturing variations and environmental effects, achieving high measurement precision without requiring complex external calibration equipment.
4Area of stationary object
If on-chip voltage regulator is used, then device footprint is reduced, but power consumption increases
Solution Approach 1:
The voltage regulator is integrated directly into the sensor interface chip, eliminating the need for external voltage regulation components. This reduces the overall device footprint and simplifies the bill of materials, accepting a moderate increase in power consumption as a trade-off for the compact integrated design.
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
Enhances sensor accuracy and sensitivity by enabling precise calibration and conditioning of multiple channels on a single chip, reducing noise and footprint, and supporting a wide range of applications with efficient power management.
Implementation Method 1
Many force and pressure sensors utilize a strain gauge or Wheatstone bridge circuit. The resistive elements in the bridge change resistance in response to changes in sensed condition, such as in pressure or acceleration, or mechanical strain, which in turn cause the electrical output (e.g., voltage or current) to change corresponding to a change in the sensed condition.
Implementation Method 2
The resistive elements in the bridge change resistance in response to changes in sensed condition, such as in pressure or acceleration, or mechanical strain
Implementation Method 3
the sensors may be biased by using a precision voltage regulator
Data Source
AI summary
A system supporting enhanced programmable signal adjustments may include a plurality of circuits configured to generate a corresponding plurality of input signals; a signal conditioner configured to condition the plurality of signals; and a controller configured to control the signal conditioner. The controller may generate one or more control signals for the controlling of the signal conditioner. The signal conditioner may select one or more input signals from the plurality of input signals, based on a first control signal generated by the controller; may generate an adjustment signal based on a second control signal generated by the controller; and may adjust at least one of the selected one or more input signals based on the adjustment signal and a third control signal generated by the controller.