LED Driver Key Matrix Decoding for Frequency-Modulated Signals
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Solution Overview
Problem
Existing systems for decoding frequency modulated signals in appliances like washing machines and dishwashers are complex and costly, consuming significant code space in microcontrollers and requiring additional components, such as dedicated ICs, which occupy board space and increase costs.
Innovation Solution
A system utilizing an LED driver with a key matrix interface to decode frequency modulated signals by pre-scaling the signal and generating interrupts, mimicking key press events, allowing the microcontroller to determine the frequency of the signal without additional coding or connections, thereby reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a microcontroller with coding instructions is used to decode frequency modulated signals, then the decoding function is achieved, but several bytes of memory are consumed and extra lines or cables are required
Solution Approach 1:
The patent extracts the frequency decoding function from the microcontroller's software code and implements it in hardware using a dedicated frequency-to-voltage converter IC. This removes the decoding logic from the microcontroller's memory, freeing up code space and simplifying the overall system architecture by separating measurement functions from control functions.
Solution Approach 2:
The frequency-to-voltage converter IC serves multiple functions: it decodes frequency modulated signals from liquid level sensors, converts them to voltage signals, and provides linearized output proportional to the measured parameter. This multi-functional component replaces what would otherwise require separate decoding code and processing logic in the microcontroller.
2Device complexity
If a dedicated IC is used for decoding frequency modulated signals, then the decoding function is achieved, but the IC occupies a substantial fraction of the board real estate and is cost ineffective
Solution Approach 1:
The patent merges the frequency-to-voltage conversion function with the existing microcontroller system by using a compact IC that interfaces directly with the microcontroller's analog input. This integration approach combines the dedicated decoding capability with the existing control architecture, minimizing additional board space while maintaining the benefits of hardware-based decoding.
3Device complexity
If a microcontroller is used to decode frequency modulated signals, then the decoding function is achieved, but extra lines or cables are required to interface the microcontroller with the liquid level sensors
Solution Approach 1:
The patent extracts the frequency decoding function from software and implements it in hardware, which eliminates the need for complex digital interface circuits and reduces the number of connection lines required between the sensor and microcontroller. The frequency-to-voltage converter IC requires only standard analog power and signal connections.
4Device complexity
If coding instructions are written in the microcontroller to decode frequency modulated signals, then the decoding function is achieved, but several bytes of memory are consumed
Solution Approach 1:
The patent extracts the frequency decoding algorithm from the microcontroller's software code and implements it in hardware logic within the frequency-to-voltage converter IC. This hardware implementation performs the decoding function automatically through analog circuitry, completely eliminating the need for decoding code in the microcontroller's memory.
Solution Approach 2:
The patent replaces the software-based decoding mechanism (which requires memory storage and processing instructions) with a hardware-based analog circuit that performs frequency-to-voltage conversion automatically. This substitution eliminates digital code requirements and uses continuous analog processing instead of discrete digital instructions.
Data Source
AI summary
A system for decoding frequency modulated signals includes a glue logic module, a key matrix, and a driver coupled to the key matrix. The glue logic module provides a pre-scaled frequency signal, while the key matrix receives the pre-scaled frequency signal. The driver decodes the pre-scaled frequency signal to generate at least one event update corresponding to a frequency of the pre-scaled frequency signal.