Unified dual mode physical layer for mobile CMOS image sensor interface

Abstract

This paper presents a new unified dual-mode physical layer (PHY) architecture that can handle both of Mobile Display Digital Interface (MDDI) and Mobile Industry Processor Interface (MIPI) in high speed mobile display application. For this, we propose a wide operation range differential Low Voltage Differential Signal (LVDS) pairs which can simultaneously handle MDDI packet and sub-LVDS MIPI stream high speed serial data. In addition, the strobe pair in MDDI mode can be used as the high speed clock transmission lane in MIPI mode with some circuit techniques such as interoperation repeater circuit and low jitter input dual mode buffer. After protocol level processing, each unpacked image data are easily connected to parallel interface for system compatibility. Therefore, this unification is very useful for an embedded camera module in mobile phone application. Several experimental results under different electrical conditions verify the good operation of the proposed architecture. The image test under two different standard Mega pixel image sensors with the random data of about 1-Gpbs shows that the unified structure works well for both MDDI and MIPI.