CMOS Image Sensor Driver Switching Parallel Serial Modes
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Solution Overview
Problem
Solid-state imaging devices, such as CMOS image sensors, face challenges in adapting to different data transmission modes like parallel and serial transmission, which affects data transmission speed and frame rate in surveillance cameras and similar systems.
Innovation Solution
The implementation of a configuration that allows CMOS image sensors to switch between parallel and serial transmission modes by using single-end and differential drivers, enabling the output of single-end signals in parallel mode and differential signals in serial mode, thereby increasing data transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-end driver is used for parallel transmission mode, then the device can maintain compatibility with existing parallel interfaces, but the data transmission speed is limited compared to differential transmission
Solution Approach 1:
The driver circuit is designed to perform multiple functions by switching between single-end drive mode for parallel transmission and differential drive mode for serial transmission. The same physical driver can output either single-end signals (for compatibility with parallel interfaces) or differential signals (for high-speed serial transmission), making the device universally adaptable to different transmission modes without requiring separate dedicated drivers for each mode.
2Speed
If a differential driver is used for serial transmission mode, then the data transmission speed is increased, but the device cannot simultaneously support parallel transmission mode
Solution Approach 1:
The driver circuit incorporates dynamic switching capability that allows it to change its operating mode based on the required transmission protocol. Control signals dynamically switch the driver between single-end output configuration (for parallel mode compatibility) and differential output configuration (for high-speed serial mode), enabling the device to adapt its characteristics in real-time according to the operational requirements.
3Device complexity
If the same output terminal is used for both parallel and serial transmission modes, then the device structure is simplified, but signal interference may occur between the two modes
Solution Approach 1:
Before switching between parallel and serial transmission modes, the driver circuit performs preliminary actions including disabling the currently active driver, switching the output configuration (single-end or differential), and enabling the appropriate driver for the target mode. This preliminary switching sequence ensures that only one driver is active at any given time, preventing signal interference and ensuring reliable transmission while using the same physical output terminals.
Data Source
AI summary
A solid-state imaging device includes a pixel array, an AD converting unit converting each of a plurality of analog signals read from the pixel array to a plurality of digital signals and outputting the digital signals, a transmission mode selection register, first and second output terminals, a single-end driver which has first and second input terminals coupled to the digital signals and which has third and fourth terminals, and a differential driver which has third and fourth input terminals coupled to the digital signals and which has fifth and sixth terminals.