A novel data transmission circuit for digital image sensors

Abstract

A novel data transmission circuit for digital image sensors is presented. Large amounts of data are divided into m groups of n bits each. Each group of data is stored in an n-bit shift register. Under the control of a column scanner, at a time, only one group of data is selected to output serially to a common output line. Thus, as the scanner scans all the groups of data, the large amounts of data are serially output through the common line. A current-mode circuit transforms the output data into a low voltage swing signal which propagates over the common output line fast. A sense amplifier receives the low voltage swing signal and then recovers the full swing signal. Finally, a low-voltage differential signaling ( LVDS ) transmitter, which is fed with the full swing signal, transmits the data out chip. Because there is always only one of the m shift registers operating, the power consumption is greatly reduced. The simulation results show that the proposed circuit works correctly at a date rate of 400Mb/s. For n=14, and m=8, 32, 128, and 256, the power consumption of the prototype is as low as 1/4, 1/15, 1/50, and 1/80 that of the traditional serial link respectively.