Integrated Humidity and Pressure Sensor Layout for Higher SNR
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Solution Overview
Problem
Existing environmental monitoring 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 locations.
Innovation Solution
Integration of environmental and temperature sensors with measurement circuitry on an Application Specific Integrated Circuit (ASIC) die, co-packaged with a pressure sensor IC, featuring integrated local heating elements and control circuitry for efficient temperature control and power management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate sensor dies are used for pressure and humidity sensing, then the sensors can be independently optimized, but parasitic capacitance increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent combines the humidity sensor die and pressure sensor die into a single integrated sensor die. The humidity sensing capacitor and pressure sensing capacitor are formed on the same die, sharing common structures such as the lower electrode, dielectric layers, and interconnects. This integration eliminates the parasitic capacitance associated with separate dies and reduces the number of external connections, thereby improving the signal-to-noise ratio.
2Volume of moving object
If separate sensor dies are used for pressure and humidity sensing, then each sensor can function independently, but the package size cannot be minimized
Solution Approach 1:
The patent integrates both humidity and pressure sensing functionalities into a single sensor die, which is then co-packaged with the ASIC die in a compact configuration. This merging approach significantly reduces the overall package size compared to using separate dies for each sensor function.
Solution Approach 2:
The sensor die is stacked on top of the ASIC die in a three-dimensional configuration. This nesting arrangement allows the sensor functions to be vertically integrated rather than horizontally arranged, further minimizing the package footprint while maintaining all necessary sensing capabilities.
3Ease of operation
If a vent hole is provided in the protective shell, then ambient air can reach the sensors, but the vent hole location becomes sub-optimal for both sensor dies
Solution Approach 1:
The patent provides a single vent hole in the protective shell that serves both the humidity sensor and pressure sensor simultaneously. This unified venting approach eliminates the need for separate vent holes for each sensor, simplifying the design while ensuring both sensors receive ambient air for proper operation.
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 solution enhances the signal-to-noise ratio, enables compact design, optimizes sensor exposure, and efficiently uses battery power by integrating sensors and heating elements within the ASIC die.
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
an environmentally sensitive material formed between, and optionally around, the first and second capacitor terminals as a dielectric
Implementation Method 3
integrated local heating elements and control circuitry that are power supply independent, make efficient use of battery power
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.