USB Hub PWM Arbitration for Uniform and Contextual LED Lighting
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Solution Overview
Problem
Automotive dashboard back-lighted modules require uniform luminance calibration, but existing methods involve altering the bill of materials, leading to increased production costs and lack of contextual lighting control based on vehicle states and ambient conditions.
Innovation Solution
An automotive USB hub with PWM master arbitration, comprising a first master for uniformity trimming, a second master for event-driven LED control, and a third master for USB host to PWM bridge, allowing for centralized arbitration and dynamic reconfiguration of PWM outputs to achieve luminance uniformity without altering the bill of materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If corrective actions are implemented through changes to the bill of materials on a per-module basis, then luminance uniformity can be achieved, but production cost increases
Solution Approach 1:
The patent introduces a USB hub as an intermediary device that centralizes PWM control functionality. Instead of modifying each individual module's bill of materials, the hub acts as a mediator that receives PWM signals and distributes them to multiple modules, achieving luminance uniformity through centralized control rather than per-module modifications
Solution Approach 2:
The USB hub provides multi-functional capability by serving as both a USB connection device and a PWM control distribution system. This universal device can control luminance across multiple different modules simultaneously, eliminating the need for separate corrective measures for each module and reducing overall production costs
2Adaptability or versatility
If discrete lighting control is provided for each module, then contextual lighting visualization can be achieved, but system complexity increases
Solution Approach 1:
The patent merges multiple PWM control functions into a single USB hub device. By combining the PWM reception, signal distribution, and contextual control capabilities in one centralized location, the system achieves adaptable lighting control for different modules while reducing the overall system complexity that would result from discrete control circuits in each module
Data Source
AI summary
A PWM lighting bridge manages hardware PWM compensation components. One or more PWM outputs are driven based upon a master PWM input signal. The master PWM input signal is processed through a mapping function to produce a desired output signal(s) on the one or more PWM outputs. The mapping function comprises a set of compensation bins having a maxim input duty cycle, a minimum input duty cycle and an output duty cycle. The mapping process selects a bin based on determining whether the input duty cycle is within the minimum and maximum duty cycle ranges of the bins and then uses the specified output duty cycle for the one or more PWM outputs. The PWM lighting bridge provides configuration and runtime management of the hardware PWM compensation components. Read/write access to the PWM compensation bins provides customizable configurations of the input and output PWM characteristics.