Image Sensor Driver Circuit Power Reduction via Time-Division Amplifier Control
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Solution Overview
Problem
Conventional image reading apparatuses face increased power consumption and heat generation due to the constant operation of multiple amplifiers during image reading, either individually for each photosensor or a single amplifier operating at higher frequencies for serial conversion.
Innovation Solution
A driver circuit with a shift signal generator, amplifiers, current controllers, and a data converter that selectively activates amplifiers based on shift signals, allowing only one amplifier to operate at a time, reducing power consumption and heat generation by controlling the supply of electrical current to each amplifier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple amplifiers operate constantly to process detection signals from photosensors, then signal amplification and parallel-to-serial conversion are achieved, but power consumption and heat generation increase significantly
Solution Approach 1:
The patent implements periodic action by controlling amplifiers to operate only during specific time intervals when detection signals need processing. The control circuit activates amplifiers in a time-division manner, turning them on during signal processing periods and turning them off during idle periods, thereby reducing overall power consumption while maintaining amplification capability when needed.
Solution Approach 2:
The patent merges the functions of multiple amplifiers into a coordinated time-division system. Instead of having multiple amplifiers operate simultaneously and independently, the control circuit combines their operations into a sequential processing scheme where amplifiers share the amplification task across different time slots, reducing total power consumption while maintaining processing throughput.
2Productivity
If multiple amplifiers operate constantly to process detection signals, then signal processing is continuous, but heat generation increases
Solution Approach 1:
The patent applies periodic action by enabling amplifiers only during necessary processing intervals and disabling them during idle periods. This time-division operation maintains signal processing throughput by ensuring amplification capability is available when needed, while significantly reducing heat generation by eliminating continuous operation and allowing thermal dissipation during off periods.
Solution Approach 2:
The patent converts the potential harm of idle amplifier power consumption into benefit by using the idle periods for thermal dissipation. The control circuit intentionally creates off-periods where amplifiers are disabled, allowing accumulated heat to dissipate, thus preventing overheating while maintaining processing productivity during active periods.
3Device complexity
If a single amplifier operates at higher frequencies for serial conversion, then device complexity is reduced, but power consumption increases due to higher operating frequency
Solution Approach 1:
The patent applies periodic action to control the single amplifier's operation, enabling it to process signals from multiple photosensors in time-division manner. The amplifier operates at standard frequency but is activated periodically for different sensor groups, achieving serial conversion functionality without requiring continuous high-frequency operation, thus reducing power consumption compared to a single amplifier running at elevated frequency continuously.
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
The solution significantly reduces power consumption and heat generation in the image reading apparatus by ensuring that only the necessary amplifiers are active during image reading, optimizing energy use and thermal management.
Implementation Method 1
a photosensor array 110Y containing a plurality of photosensors PSy comprised of photodiodes PD
Data Source
AI summary
A driver circuit provided with a shift signal generator for sequentially outputting shift signals at a predetermined time interval; a plurality of amplifiers respectively receiving a plurality of detection signals read out in parallel corresponding to a detectable object image pattern and respectively receiving the shift signals, wherein the plurality of amplifiers respectively amplify and output the detection signals inputted thereto based on the output timing of each of the shift signals inputted thereto; a data converter for outputting in time series each of the amplified detection signals outputted from each of the amplifiers based on the output timing of each of the shift signals and for generating time series read data. Power consumption and the amount of heat generation are suppressed in the driver circuit provided with means to individually control a supply state of electrical current to each of the amplifiers.