Sensors offer 1.2 to 8.3MP resolution, ASIL-C safety, and high dynamic range.
By Murray Slovick, Contributing Editor
As the industry moves from Level 2 systems for emergency autonomous braking, adaptive cruise control, and lane change assistance toward fully autonomous driving, image sensors must enable increasingly demanding Advanced Driver Assistance Systems (ADAS) and self-driving capabilities. To that end, at the recent Consumer Electronics Show (CES) in Las Vegas, ON Semiconductor introduced a new family of CMOS image sensors with resolutions scaling from 8.3 megapixels (MP) down to 1.2 MP, with low-light performance claimed to be an industry-leading 4.2 µm pixels.
The AR0820AT, AR0220AT, and AR0138AT sensors provide a range of resolutions to address segmentation in automaker’s product lines, where specific safety features are standard, but additional or higher-resolution cameras enable more advanced safety and add-on capabilities as customer options.
Additional features include functional safety up to ASIL-C, high-dynamic range (HDR), a cybersecurity option, and second-generation wafer stacking technology that reduces package size. Individual products in this platform are said by the company to be under evaluation by technology partners such as Mobileye and NVIDIA, the latter for use with its DRIVE AI computing platform for autonomous vehicles.
The AR0820AT, for example, is a 1/2-in. CMOS digital image sensor with a 3848 H × 2168 V active-pixel array. This sensor captures images in either linear or high dynamic range, with rolling-shutter readout. (In rolling shutter mode, the frame rate is determined by the speed of the A/D [clocking frequency] and the number of rows on the sensor, whereas in Global Shutter mode, every pixel is exposed simultaneously at the same instant in time.) ON Semiconductor says AR0820AT is optimized for both low light and high dynamic range scene performance, with a 2.1 µm DR-Pix BSI (backside illuminated) pixel and on-sensor 140 dB HDR capture capability.
A quick word on dynamic response (DR). Although picture resolution is increasing in today’s camera systems, the DR of pixels continues to decrease as pixel sizes shrink, thereby limiting the ability to produce natural photos with both highlights and shadows preserved. ON Semiconductor’s DR-Pix technology offers dual conversion gain for improved performance under all lighting conditions, according to the company.
The AR0820AT includes functions such as in-pixel binning, windowing, and both video and single frame modes to provide flexible region of interest (ROI) or specific resolution in order to enhance performance in extreme low light conditions. The device is programmable through a two-wire serial interface and supports the MIPI output interface.
The 4.2 µm pixel’s architecture is useful in low-light scenarios such as night-time emergency braking for pedestrians and cyclists that is being added to safety tests defined by Euro NCAP. The sensor family’s cybersecurity technology helps ensure reliable and secure operation when multiple cameras around the vehicle are connected to a centralized system, where data and commands must travel by wires between the sensor and the processor.
For advanced imaging capabilities, software and algorithm testing is typically the longest task in the development program. With ON Semiconductor’s family of scalable image sensors, customers can start early development with one sensor to adapt their algorithms to the pixel performance and system features, and then extend to additional resolutions with further testing. This shortens project time-to-market and reduces overall development costs across a family of camera system implementations.
In related automotive news, ON Semiconductor announced it has joined the global Charging Interface Initiative e.V. (CharIN) ecosystem, whose aim is to promote standards for charging systems in electric vehicles (EVs), as well as developing a certification system for manufacturers to implement charging systems into their products.
“At ON Semiconductor, our core business is power management, and we support virtually every requirement with products that range from low drop-out regulators to switched mode power supplies to sophisticated power management ICs (PMICs),” said Ali Husain, senior manager, power conversion and motor control solutions. “We are seeing a ramp-up of our IGBT modules and FETs for electric vehicle charger designs.
“We expect next-generation semiconductor materials such as silicon carbide and gallium nitride to drive improving power density and efficiency,” Husain added. “We look forward to bringing this expertise to the CharIN ecosystem and collaborating with other industry leaders to create a Combined Charging System and supporting the continued evolution of EV charging infrastructure.”