Time-of-flight IC for optical object detection/ranging within 2m

October 15, 2015 // By Graham Prophet
Intersil’s ISL29501 signal processing IC detects objects up to two metres away; the device is a time-of-flight (ToF) signal processing IC that provides a complete object detection and distance measurement solution when combined with an external emitter (LED or laser) and photodiode.

The ISL29501 ToF device offers ultra-small size, low-power consumption and superior performance ideal for connected devices, as well as consumer mobile devices and the emerging commercial drone market.

The ISL29501 overcomes the shortcomings of traditional amplitude-based proximity sensors and other ToF solutions that perform poorly in lighting conditions above 2,000 lux, or cannot provide distance information unless the object is perpendicular to the sensor. Alternative solutions are – Intersil asserts – too expensive, bulky or power-hungry for use in small form factor, battery-powered applications. The ISL29501 sensor provides a small solution footprint and precision long-range accuracy up to two metres in both dark and bright ambient light conditions. It allows designers to select the emitter and photodiode of their choice and configure a low power ToF sensing system customised for their application. Intersil offers a reference design featuring the ISL29501, emitter and photodiode, along with graphical user interface (GUI) software and user’s guide.

The ISL29501 incorporates power saving and extends battery life through several innovations. The on-chip emitter DAC with programmable current up to 255 mA allows system designers to select the desired current level for driving the external infrared (IR) LED or laser. This feature enables optimisation of distance measurement, object detection and power budget. The device’s single shot mode saves power by allowing designers to define the sampling period for initial object detection and approximate distance, while continuous mode more accurately measures distance. The ISL29501 also performs system calibration to accommodate performance variations of the external components across temperature and ambient light conditions.

“Prior to Intersil’s time-of-flight technology breakthrough, there was no practical way to measure distance up to two metres in a small form factor,” said Andrew Cowell, senior vice president of Mobile Power Products at Intersil. “The ISL29501 provides customers a cost-effective, small footprint solution that also gives them the flexibility to use multiple devices to increase the field of view to a full 360 degrees