Ambient lighting control on small footprint

November 15, 2012 // By Christoph Hammerschmidt
Atmel Corp. has introduced a new family for automotive switch scan applications and in-vehicle ambient lighting control that communicates via LIN bus. The new devices ATA664151 and ATA664251, include a broad range of on-chip functionalities that competing solutions can achieve only by combining multiple devices.

Available in ultra-small packages measuring just 5x5mm and 7x7mm, these new LIN devices reduce the end-application footprint, cutting down the overall cost and development time for automotive ambient lighting applications.

Switch scan applications used in automotive doors, roof modules, and center stacks benefit from an extremely low sleep mode power consumption. The current sources are controlled by three independent pulse-width modulation (PWM) signals, which makes the devices suited for ambient lighting solutions controlling RGB LEDs.

The ATA664151 and ATA664251 LIN devices include an eight-channel high-voltage switch interface with current sources and analog voltage multiplexer to scan switches in automotive applications with currents up to 20mA. The integrated state change detector allows switch scan applications with extremely low current consumption. The current sources are controlled by three independent PWM signals enabling the device to act as an ambient light circuit to control RGB LEDs. A LIN 2.2 and SAEJ2602-2-compliant transceiver, based on Atmel's third-generation LIN transceiver IP as well a low-drop 5V voltage regulator with 80mA current capability and an adjustable window watchdog are also included.

The ATA664251 is a system-in-package solution with an ATA664151 chip and an Atmel AVR 8-bit ATtiny167 microcontroller (MCU). The low-power RISC-based MCU combines 16KB Flash memory, 512B EEPROM, 512-Byte SRAM, 16 general-purpose I/O lines, 32 general-purpose working registers, 8-bit and 16-bit timer/counter units with compare modes, a universal serial interface (USI), a LIN UART, internal and external interrupts, an 11-channel 10-bit A/D converter and three software selectable power-saving modes.