Antwerp-based CMOSIS has introduced an image sensor that yields a 89.5dB dynamic range using a dual-gain pixels.
The 1Mpixel device is a technology demonstrator that achieves its high dynamic range in two ways.
First is a very low dark noise, of less than 3.4 electrons for a full well capacity of 100,000 electrons.
Second is that the integration of the image charge takes place simultaneously at a low and a high amplification through two separate amplifiers.
This dual-gain read-out results in two different images which are output sequentially and combined externally into one final image."
"Due to the two-fold readout of each pixel, the sensor has twice the number of column amplifiers than columns. Their amplification factors are programmable at 1x to 16x," said the firm.
Multiplexers are provided to select the column and transfer the analogue signals to a three-stage output circuit, which consists of an amplifier for correlated double sampling at 1x, 2x or 4x and programmable offset, a limiter and an output driver.
"Analogue to digital conversion is done off-chip while programmable amplification and offset can adapt the sensor to different A/D converters," said the firm. "The limiter will spring into action when a subsequent converter needs more time to recover after a heavy overdrive, which is not tolerated by many applications."
A serial interface is included for setting the internal parameter selection registers, but all run-time control has to be provided externally on the demonstrator.
"Based on this 1Mpixel sample, CMOSIS will design and implement a number of future sensor products for specific applications," said the firm. "These products may integrate run-time control and ADC, and deliver higher frame rates or special pixel sizes."
Applications are foreseen in scene monitoring and analysis, medical diagnostics, astronomy, microscopy, spectroscopy, industrial image processing, X-ray radiography, and luminescence and fluorescence-based applications.
The demonstrator at a glance
Dubbed CLN1000, it features a 1024x1024 array laid out on a 10x10µm grid.
The 2048 amplifiers are combined by four 512:1 multiplexers which feed into four 16Msample/s analogue output channels.
These can be further combined by a 4:1 multiplexer to deliver 64Msample/s up to a maximum frame rate of 20frame/s.
It consumes 300 to 350mW, and is housed in a JLCC-84 package.