User-Interface LED Driver Provides Front-Panel Activity Control

The AS1115 user interface (UI) LED driver combines display driving and key scanning, providing a complete front panel solution that eliminates the need for a secondary microprocessor or other discrete devices. It can drive either eight 7-segment digits or 64 individual LEDs with 47 mA per digit or 5 mA per LED. An external resistor can easily adjust the current. With ±3% accuracy, the AS1115 improves picture quality for LED displays thanks to minimized intensity variations between the LEDs and LED modules. A 4-bit PWM controls global digital brightness or separate dimming of each single digit. In addition, the AS1115 driver offers the read back of up to 16 keys, completing the single-chip UI solution. A unique feature is the built-in LED error detection. The user-friendly software interface allows error diagnostics to be easily accessed during normal operation. Any open or short circuit within the multiplexed 8-by-8 LED array can be detected, and a detailed error report can be read out with the exact position of the broken LED. The AS1115 operates from a single 2.7- to 5.5-V supply while requiring a supply current of 0.6 mA during operation and 200 nA in shutdown mode. The AS1115 interfaces with up to four devices on a single I²C bus. Operating temperature ranges from -40°C to +85°C. The AS1115 comes in a 24-pin QSOP package. For space sensitive applications, a TQFN-24 package is also available. AUSTRIAMICROSYSTEMS, Unterpremstaetten, Austria. +43 3136 500-0.