Illumination Driver Circuit for Barcode Readers
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Solution Overview
Problem
Imaging-based barcode readers face challenges in minimizing power supply noise interference, particularly when switching from pulse mode to continuous mode, which can affect the accuracy of barcode reading due to the Buck regulator's discontinuous operation.
Innovation Solution
An illumination driver circuit is introduced, combining a Buck regulator and a linear regulator with a selection switch, where the Buck regulator operates in continuous mode above a threshold current and switches to the linear regulator below it, maintaining a stable power supply and minimizing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Buck regulator is used to provide driving current for the illumination source, then power efficiency is improved, but power supply noise interference increases when operating in discontinuous mode
Solution Approach 1:
A linear regulator is introduced as an intermediary component between the power source and the illumination source to replace the Buck regulator during continuous mode operation. The linear regulator acts as a mediator that eliminates the switching noise generated by the Buck regulator while maintaining efficient power delivery, thus resolving the contradiction between power efficiency and noise interference.
Solution Approach 2:
The system dynamically switches between Buck regulator and linear regulator based on operating conditions (continuous vs. discontinuous mode). This dynamic adaptation allows the system to use the Buck regulator for power efficiency during discontinuous mode when noise is less critical, and switch to the linear regulator during continuous mode to minimize noise interference, thereby resolving the technical contradiction.
2Loss of energy
If the Buck regulator operates in discontinuous mode, then power consumption is reduced, but reading accuracy deteriorates due to noise interference
Solution Approach 1:
The linear regulator serves as an intermediary that filters out power supply noise during continuous mode operation, ensuring that the illumination source receives clean power. This intermediary component maintains reading accuracy by eliminating noise interference while allowing the system to operate in continuous mode with optimized power consumption.
Solution Approach 2:
The system dynamically selects the appropriate regulator based on the required reading accuracy and power consumption conditions. When high reading accuracy is required, the system switches to the linear regulator to eliminate noise. When power consumption optimization is the priority and noise interference is acceptable, the Buck regulator in discontinuous mode is used. This dynamic selection resolves the contradiction between power consumption and reading accuracy.
3Device complexity
If a single regulator is used for all current demands, then device complexity is reduced, but performance consistency deteriorates across varying current demands
Solution Approach 1:
The power regulation function is segmented into two specialized components: a Buck regulator optimized for discontinuous mode operation and a linear regulator optimized for continuous mode operation. Each regulator handles specific operating conditions where it performs optimally, ensuring consistent performance across varying current demands. This segmentation resolves the contradiction by allowing each component to excel in its designated operating range.
Solution Approach 2:
The system dynamically switches between the Buck regulator and linear regulator based on the current operating conditions and current demand. This dynamic adaptation ensures that the appropriate regulator is used for each specific operating scenario, maintaining performance consistency across the full range of current demands while managing complexity through intelligent control.
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 ensures consistent and noise-free power delivery to the illumination source, enhancing the accuracy and reliability of barcode reading across varying current demands, thereby improving the overall performance of imaging scanners.
Implementation Method 1
The illumination driver circuit, which includes a Buck regulator and a linear regulator
Implementation Method 2
The illumination driver circuit, which includes a Buck regulator and a linear regulator
Implementation Method 3
an illumination source for providing illumination directed toward a target object
Implementation Method 4
a solid-state imager having an array of photosensitive elements for capturing an image from the target object
Data Source
AI summary
Illumination driver circuit for using in an imaging-based barcode reader is configured to provide the driving current for the illumination source with a Buck regulator when the driving current is above a threshold current value and to provide the driving current for the illumination source with a linear regulator when the driving current is not above the threshold current value. The threshold current value is substantially close to the smallest current the Buck regulator operative to provide when operating in a continuous mode.