ams – Sensor-driven system-on-chip to speed adoption of variable-CCT and daylight-responsive LED lighting


ams has introduced the AS7225 smart system-on-chip sensor for tunable white lighting, based on ams technology for closed-loop CCT tuning and daylight compensation.

Interfacing to an existing host microprocessor in a smart lighting design, the AS7225 enables lighting OEMs to benefit from higher precision, more flexible LED binning and lower system costs for tunable white lighting systems.

The AS7225 is equipped with an industry- first embedded tri-stimulus CIE XYZ colour sensor to enable precise colour sensing with direct mapping to the International Commission on Illumination (CIE) 1931 colour space, which is recognised as the standard co-ordinate definition for human perception of colour. CCT and daylighting tuning directives, or instructions, are communicated to the host processor via an industry-standard I2C interface.

The AS7225 is supplied in a 20-pin LGA package measuring 4.5mm x 4.7mm x 2.5mm. The package has an aperture offering a ±20.5° field of view. It allows for flexible integration into luminaires, light engines and larger replacement lamps, such as LED linear T-LED products.

Facing inward toward the light source, the device provides precise CCT tuning by balancing the output from configured warm and cool white LED strings in a luminaire. Facing outward, the AS7225 can be used in luminaire designs to provide precise daylight management. It can also provide combined CCT-tuning and daylighting directives with the addition of an ams TSL4531 ambient light sensor.

Also in the ams family of Cognitive Lighting products is the AS7221, a networking-enabled IoT Smart Lighting Manager with the same tri-stimulus colour sensor. IoT luminaire control is performed through a network connection, or by direct connection to 0-10V dimmers, with control outputs that include a direct PWM channel to LED drivers, and analogue 0 to 10V signals to dimming ballasts.

A simple text-based Smart Lighting Command Set and serial UART interface enable easy integration with standard network clients.


  • Comprehensive register-driven command set enabling complete sensor control plus management of precision tuning directives
  • Readable registers for CIE 1931 and CIE 1975 colour-point coordinates, CCT, du’v’ and lux
  • Simple register-based commands to control and configure key light-tuning supervisory functions
  • Calibrated nano-optic silicon interference filters


  • Tunable white LED lighting

The AS7225 demo kit consists of a mezzanine-style PCB which includes the AS7225 Smart Lighting Director, warm/ cool LED strings for tunable white capabilities, and an on-board 8051 microcontroller which interfaces to the graphical user interface and LED strings, and executes the colour tuning directives.

Orderable Part Number: AS7225 DEMO KIT