Time-of-flight IC for optical object detection/ranging within 2m
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 for enhanced object detection capabilities.”
Features include;
– On-chip DSP calculates ToF for accurate proximity detection and distance measurement up to two metres
– Modulation frequency of 4.5 MHz prevents interference with other consumer products such as IR TV remote controls that operate at 40 kHz
– On-chip emitter DAC with programmable current up to 255 mA allows designers to choose the desired current level to optimise distance measurement and power budget
– Operates in single shot mode for initial object detection and approximate distance measurement, while continuous mode improve distance accuracy
– On-chip active ambient light rejection minimises or eliminates the influence of ambient light during distance measurement
– Programmable distance zones: allows the user to define three ToF distance zones for determining interrupt alerts
– Interrupt controller generates interrupt alerts using distance measurements and user defined thresholds
– Automatic gain control sets optimum analogue signal levels to achieve best SNR response
– Supply voltage range of 2.7V to 3.3V
– I²C interface supports 1.8V and 3.3V bus
The ISL29501 signal processing IC in a low profile 4 x 5 mm, 24-lead TQFN package is priced at $4.87 (1000). The ISL29501-ST-EV1Z reference design board is $250. Engineers can use it along with Intersil’s ToF GUI software and user’s guide.
Intersil; https://www.intersil.com/products/isl29501
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