Solid-State Imaging Device Dual A/D Conversion Power Management
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Solution Overview
Problem
Solid-state image pickup devices face challenges in reducing power consumption as the number of pixels increases and imaging speed improves, leading to higher power consumption and potential heat generation issues.
Innovation Solution
The device incorporates a charge storing section for each pixel and a triggering photodiode region, allowing for differential power usage based on output periods, with a common output section operating at lower power during triggering data output and higher power during pixel data output, utilizing separate A/D converting circuits optimized for each mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of pixels is increased and imaging speed is improved, then imaging quality and productivity are enhanced, but power consumption increases
Solution Approach 1:
The output section is segmented into two separate A/D converting circuits: an imaging A/D converting circuit for processing pixel data and a triggering A/D converting circuit for processing triggering data. This segmentation allows independent optimization of each circuit's power consumption characteristics, enabling the triggering circuit to operate at lower power while the imaging circuit handles high-speed data conversion.
Solution Approach 2:
The patent implements dynamic operation modes where the output section can switch between different operating states. During triggering data output periods, the imaging A/D converting circuit is suspended and only the triggering A/D converting circuit operates at lower power. During pixel data output periods, the imaging A/D converting circuit operates at higher power. This dynamic switching optimizes overall power consumption while maintaining high-speed imaging capability when needed.
2Measurement precision
If the number of pixels is increased, then imaging resolution is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by suspending the imaging A/D converting circuit during periods when only triggering data needs to be output. Instead of continuously operating both A/D converting circuits at full capacity, the system activates only the necessary circuit for the current operational phase, reducing overall power consumption while maintaining the capability for high-resolution imaging when actually needed.
3Speed
If the output section operates at high speed to output pixel data, then imaging speed is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic action through time-division multiplexing, where the output section alternates between different operational phases. During triggering data output periods, the system operates in a low-power mode with only the triggering A/D converting circuit active. During pixel data output periods, the system switches to high-speed mode with the imaging A/D converting circuit active. This periodic switching between operational states reduces average power consumption while maintaining high-speed capability when required.
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 approach effectively suppresses power consumption increases while enabling higher pixel counts and faster imaging, particularly beneficial for applications like X-ray imaging in oral cavities where power efficiency is critical.
Implementation Method 1
each of the plurality of pixels included in the imaging region has a photodiode that generates electric charge of an amount according to an incident light amount
Data Source
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AI summary
The solid-state image pickup device 1 includes an imaging region 10, a triggering photosensitive region 20, a row selecting section 30, a column selecting section 40, a voltage holding section 50, an output section 60, and a controlling section 70. The solid-state image pickup device 1 reads out triggering data by the triggering photosensitive region 20, the integrating circuit 62, and the triggering A/D converting circuit 64 before light incidence, and senses the light incidence on the basis of the triggering data. After the solid-state image pickup device senses the light incidence, the solid-state image pickup device reads out pixel data by the imaging region 10, the voltage holding section 50, a differential operating circuit 61, and an imaging A/D converting circuit 63.