Solid-state imaging device intermittent driving
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Solution Overview
Problem
Conventional solid-state imaging devices achieve low power consumption through low-speed data output, resulting in limited power reduction and slow high-speed readout of pixel data.
Innovation Solution
A solid-state imaging device with a signal processing unit that digitizes and transfers pixel data at a high speed, followed by storage in a memory unit and low-speed readout, along with intermittent driving that stops the current source and AD converter operations to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the data output unit operates at low speed to reduce power consumption, then power consumption is reduced, but the readout speed of pixel data becomes slow
Solution Approach 1:
The patent segments the data transfer process into two distinct phases: a high-speed transfer phase where pixel data is rapidly transferred from the pixel array to the non-volatile memory, and a low-speed readout phase where data is read from the memory at lower speed. This segmentation allows the system to achieve both high readout speed (during transfer) and low power consumption (during readout and storage), resolving the contradiction between speed and energy consumption.
2Speed
If the data output unit operates at high speed to improve readout speed, then readout speed is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic action by alternating between high-speed data transfer operations and low-speed readout operations. The non-volatile memory serves as a buffer that allows the system to perform rapid data acquisition followed by slower data retrieval, creating a periodic pattern of high and low power consumption states that overall reduces energy usage while maintaining high effective readout speed.
3Productivity
If a non-volatile memory is used to store pixel data, then high-speed reading is enabled, but the data output unit must operate at low speed to maintain low power consumption
Solution Approach 1:
The non-volatile memory acts as an intermediary buffer between the high-speed pixel array and the low-speed data output unit. This mediator allows the pixel data to be rapidly stored in the memory during the transfer phase, then read out at lower speeds during the readout phase, enabling the system to decouple the speed requirements of data acquisition from data retrieval while managing power consumption effectively.
Data Source
AI summary
The solid-state imaging device of the present disclosure includes a signal processing unit including an AD converter that digitizes an analog pixel signal read from each pixel of the pixel array unit to a signal line, the signal processing unit transferring digitized pixel data at a first speed higher than a frame rate; a memory unit that stores the pixel data transferred from the signal processing unit; a data processing unit that reads pixel data at a second speed lower than the first speed from the memory unit; and a control unit that, when the pixel data is read from the memory unit, controls to stop operation of a current source connected with the signal line and operation of at least the AD converter of the signal processing unit.