Automotive image sensors bring LED flicker mitigation

Taner Ozcelik, Senior Vice President and General Manager of ON Semiconductor’s Image Sensing Group estimates the market will reach $1bn by 2018. He reckons his company’s position as the number one supplier to the automotive market leaves it well placed to take advantage.

“Forward looking ADAS is becoming integral to driver and pedestrian safety,” says Ozcelik. This means viewings systems are starting to adopt ADAS, including object detection with automatic electronic braking.

“ADAS requirements in the future include low light SNR (signal to noise ratio), flicker free HDR (high dynamic range), high temperature operation, high resolution, improved colour definition, small size and with an eye on cost, Ozcelik explains.

ON Semicondiuctor’s answer is LED Flicker Mitigation image sensor mitigation (LFM) technology in a new 2.3 megapixel (MP) CMOS image sensor that sets a new benchmark for automotive Advanced Driver Assistance Systems (ADAS) applications.

Capable of capturing 1080p high dynamic range (HDR) video, the AR0231A also includes features that support Automotive Safety Integrity Level B (ASIL B).   

The LFM technology (patent pending) eliminates high frequency LED flicker from traffic signs and vehicle LED lighting and allows Traffic Sign Reading algorithms to operate in all light conditions. The sensor has a 1 / 2.7 in. (6.82 mm) optical format and a 1928 (horizontal) x 1208 (vertical) active pixel array. It uses the latest 3.0 micron Back Side Illuminated (BSI) pixel with ON Semiconductor’s DR-Pix technology, which offers dual conversion gain for improved performance under all lighting conditions. It captures images in linear, HDR or LFM modes, and offers frame-to-frame context switching between modes. 

The new device offers up to 4-exposure HDR, capturing more than 120dB dynamic range with superior noise performance. The AR0231AT is capable of multi-camera synchronisation support to ease implementation in vehicle applications with multiple sensor nodes, and user programmability is achieved via a simple two-wire serial interface. It also has multiple data interfaces including MIPI, parallel and HiSPi.

Other key features include selectable automatic or user controlled black level control, spread-spectrum input clock support and multiple colour filter array options. 

The AR0231AT is offered in an 11 mm x 10 mm iBGA-121 package and engineering samples are available now.  It has an operating temperature range of -40 to +105 degrees C (ambient) and will be fully AEC-Q100 qualified.  It will be available in mass production in 2016.