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Austriamicrosystems has introduced the AS1121, a 30V, 40mA, 16-channel LED driver designed to meet the needs of high-end LED video walls where excellent picture quality is demanded.

The LED driver has 12-bit pulse width modulation (PWM), dot correction and diagnostics.

With a 30V LED supply voltage, the AS1121 reduces the number of external support components compared with alternative devices and can therefore be used directly with 24V (or higher) supplies.

The AS1121 LED driver can be used for LED backlight driving in monitors and televisions, or to generate ambient light patterns.

It features a 6-bit dot correction feature for full-colour LED displays, such as stadium displays, outdoor and indoor displays, displays for public transport, street signs and LED video walls.

The AS1121 is 16-channel, constant-current sink LED driver.

Each of the 16 channels can be individually adjusted by a 4,096-step greyscale PWM brightness control (equals 6.8 billion colours) running at 10MHz as well as by a 64-step constant-current sink for dot correction.

The dot correction circuitry adjusts the typical brightness variations of LEDs on each channel.

The greyscale control and dot correction circuitry are accessible via the SPI-compatible serial interface.

A single external resistor sets the maximum current value of all 16 channels.

An open-LED detection function indicates a broken or disconnected LED at one or more of the outputs.

Other features include an over-temperature signal and a power-down pin that can put the AS1121 LED driver IC into a 40nA standby mode.

Austriamicrosystems’s AS1121 16-channel LED driver provides noise-reduction features to make sensitive LED applications easier to build.

To prevent high inrush currents, the AS1121 offers a controlled output delay grouped by four channels.

The controlled delay allows the best picture quality to be maintained, even with the shortest PWM cycles, while reducing current peaks that sometimes generate audible noise on capacitors.

For EMI-sensitive applications, the rise and fall times can be programmed at the factory.

Rene Wutte, marketing manager for lighting products at Austriamicrosystems, said: ‘Top-quality displays provide high colour depth and brightness, high frame rates and excellent contrast ratio in order to be used outdoors, especially in bright sunlight.

‘Additionally, LED error detection is an important factor for optimising maintenance cost and to guarantee high picture quality,’ Wutte added.

The AS1121 LED driver IC is ‘drop-in’ compatible with Austriamicrosystems’s previously introduced AS1112 and can be used with the same software.

Housed in a 5 x 5mm 32-pin TQFN package, the AS1121 LED driver is specified for operation from a 3.3V power supply over an ambient temperature range of -40C to +85C.


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