austriamicrosystems - LED driver with front-panel activity control

The AS1115 can drive either eight 7-segment digits or 64 individual LEDs with 47mA per digit or 5mA per LED. An external resistor can easily adjust the current. With an excellent accuracy of ±3%, the AS1115 improves picture quality for LED displays, this is due to minimised intensity variations between the LEDs and LED modules. For either global digital brightness control, or separate dimming, of each single digit a 4-bit PWM is implemented. Additionally the AS1115 offers the read back of up to 16-keys completing the single chip UI solution.

A unique feature of austriamicrosystems’ AS1115 is the built-in LED error detection. Simple and intuitive to use, the user-friendly software interface allows the error diagnostics to be easily accessed during normal operation. This solution can detect any open- or short-circuit within the multiplexed 8x8 LED array, and a detailed error report can be read out with the exact position of the broken LED, this is especially helpful to reduce test time during production.

“Due to the extremely competitive market, today’s consumer electronics or home appliance producers are under constant pressure to reduce costs. Most user interfaces demand a display to show information and buttons to interact with. Additionally, LED error detection is a very important factor to reduce test, production and maintenance cost,” said Bruce Ulrich, Director Marketing Standard Linear at austriamicrosystems. “The AS1115 addresses all these needs and helps designers achieve a more efficient, more simplified design, for front panels, such as those found on set-top boxes, DVD players, washing machines, dryers and microwave ovens.”

The AS1115 operates from a single 2.7V to 5.5V supply while requiring the lowest supply current of 0.6mA during operation and 200nA in shutdown mode. The AS1115 interfaces via I²C and up to four devices can be addressed on a single I²C bus.