Integrated Humidity-Pressure Sensor Layout for Low Parasitic Capacitance
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Solution Overview
Problem
Existing integrated circuit (IC) products with separate pressure and humidity sensor dies suffer from increased parasitic capacitance, reduced signal-to-noise ratio, and limited miniaturization due to separate sensor dies, as well as sub-optimal vent hole placement affecting sensor exposure.
Innovation Solution
Integration of environmental and temperature sensors with measurement circuitry on an ASIC die, including capacitor structures, analog-to-digital converters, and local heating elements, which are power supply independent and provide digital closed-loop control, allowing for a compact and sensitive environment monitoring product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate sensor dies are used for pressure and humidity sensing, then sensor functionality is achieved, but parasitic capacitance increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent combines the humidity sensor, temperature sensor, and pressure sensor into a single integrated sensor die. The humidity sensor includes capacitor structures with environmentally sensitive dielectric material formed between capacitor terminals on the sensor die, eliminating the need for separate humidity sensor dies and reducing parasitic capacitance to the ASIC.
Solution Approach 2:
The integrated sensor die is divided into distinct functional regions including capacitor structures for humidity sensing, temperature sensor elements, and pressure sensing areas. This segmentation allows each sensor type to operate independently while being physically integrated, reducing inter-sensor interference and parasitic effects.
2Volume of moving object
If separate sensor dies are used for pressure and humidity sensing, then sensor functionality is achieved, but package miniaturization is limited
Solution Approach 1:
The patent integrates multiple sensor functions (humidity, temperature, pressure) into a single sensor die that can be stacked on the ASIC die. This consolidation reduces the total number of discrete components and enables smaller package sizes compared to using separate sensor dies for each sensing function.
Solution Approach 2:
The sensor die is stacked on top of the ASIC die in a three-dimensional configuration, utilizing vertical space rather than horizontal expansion. This nesting approach allows the sensor functions to be integrated within a compact volume, enabling product miniaturization.
3Ease of operation
If vent hole is placed in protective shell, then external air can reach sensors, but vent hole location may be sub-optimal for sensor exposure
Solution Approach 1:
The protective shell is designed with strategically positioned vent holes or openings located at specific regions that optimize exposure to the sensor elements. The vent hole placement is tailored to the local sensing requirements, ensuring maximum interaction between ambient air and the sensor surfaces while maintaining structural integrity.
4Measurement precision
If heating elements are added for temperature control, then temperature compensation is improved, but power consumption increases
Solution Approach 1:
The heating elements are controlled to operate in periodic or pulsed manner rather than continuously. The temperature control circuitry activates the heating elements only when temperature compensation is needed, such as during calibration phases or when temperature drift is detected, thereby reducing overall power consumption while maintaining measurement precision.
Solution Approach 2:
The temperature sensor provides continuous feedback to the control circuitry, which adjusts heating element activation based on actual temperature conditions. This closed-loop control ensures heating is applied only when and where needed for accurate temperature compensation, minimizing unnecessary power consumption.
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
This integration reduces parasitic capacitance, enhances signal-to-noise ratio, optimizes sensor placement, and enables efficient battery power use, resulting in a more compact and sensitive environment monitoring solution.
Implementation Method 1
an environmentally sensitive material formed between, and optionally around, the first and second capacitor terminals as a dielectric, the environmentally sensitive dielectric material being responsive to a selected environmental characteristic so as to cause a measurable change in capacitance and/or electrical charge across the capacitor structure
Implementation Method 2
integrated local heating elements and control circuitry
Data Source
AI summary
Novel integrated circuit environmental and temperature sensors in combination with measurement circuitry fully integrated as part of an ASIC die, which may be co-packaged with a pressure sensor integrated circuit to create a compact yet sensitive environment monitoring product. Embodiments may include one or more integrated local heating elements and control circuitry that are power supply independent, make efficient use of battery power, include an accurate in-built temperature detection capability, and provide digital close-loop control of the heating elements.