Microprocessor Thermistor Sensing via Shared A/D Switching
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Solution Overview
Problem
The existing sensing apparatus requires a complex structure with multiple fixed resistors and filter circuits for each thermistor, leading to increased component count and circuit complexity when taking temperature information from multiple thermistors into a microprocessor.
Innovation Solution
A microprocessor with internal switches and switch ports that allow selective grounding of electrical elements, enabling the digital conversion of analog quantities without the need for multiple fixed resistors and filter circuits, thereby simplifying the circuit configuration and reducing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple thermistors are connected to multiple A/D conversion ports with separate fixed resistors and filter circuits, then each thermistor can be independently measured, but the structure becomes complicated and the number of components increases
Solution Approach 1:
The microprocessor's internal switches and switch ports are designed to serve multiple functions: they can selectively ground different electrical elements (thermistors) and route their analog quantities to a single A/D conversion port. This multi-functional design eliminates the need for separate dedicated circuits for each thermistor, thereby reducing component count while maintaining the ability to measure multiple temperatures independently
Solution Approach 2:
Multiple separate measurement circuits (each consisting of a thermistor, fixed resistor, and filter circuit) are merged into a unified circuit architecture where a single A/D conversion port serves all thermistors. The internal switches act as routing mechanisms that combine multiple signal paths into one, achieving circuit simplification without sacrificing measurement capabilities
2Measurement precision
If multiple fixed resistors and filter circuits are provided for each thermistor, then accurate temperature detection is achieved, but the number of components increases
Solution Approach 1:
A single fixed resistor and filter circuit are designed to serve multiple thermistors sequentially through the internal switching mechanism. The same components are reused for different measurement channels at different times, dramatically reducing the total number of components required while maintaining measurement accuracy for each thermistor
Solution Approach 2:
The measurement system operates in a periodic sequence where internal switches sequentially connect different thermistors to the shared A/D conversion port. Each thermistor is measured in turn during specific time intervals, allowing a single set of passive components (resistor and filter) to serve multiple sensing elements without interference, thus reducing component quantity while preserving detection accuracy
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 configuration allows for the effective digital conversion of analog quantities from multiple thermistors using a single A/D conversion port, reducing the number of components and simplifying the structure, while maintaining efficient temperature monitoring capabilities.
Implementation Method 1
a plurality of internal switches provided in the microprocessor; and a plurality of switch ports that are provided in the microprocessor and can be selectively grounded by the internal switches
Implementation Method 2
a microprocessor (an IC) having an A/D converting function has been developed. This type of microprocessor digital-converts an analog electric quantity (a voltage) given to an A/D conversion port thereof and takes in a conversion result
Implementation Method 3
temperature information (an analog voltage value) detected by a thermistor (a temperature sensing element) is inputted to the microprocessor
Data Source
AI summary
A sensing apparatus includes a microprocessor having an A/D converting function of digital-converting an analog electric quantity supplied to an A/D conversion port and taking in a conversion result, and a plurality of electrical elements that are connected with the microprocessor and generate analog electric quantities. The plurality of electrical elements are respectively connected with a plurality of switch ports in the microprocessor that can be selectively grounded by internal switches of the microprocessor. Analog electric quantities generated in the electrical elements can be selectively taken into the A/D converting function of the microprocessor by selectively switching the internal switches.