austriamicrosystems unveil third generation of LED drivers for use in both LCD edge – and direct-lit TVs
The new AS382x LED controller ICs are available as the 16-channel AS3820 and the 12-channel AS3821 to meet the needs of the most common architectures of both direct and edge-lit LED TVs. Both ICs feature ±0.2% channel-to-channel accuracy – the highest accuracy available – to guarantee the best possible light uniformity and picture quality. The ICs can be used for driving external power MOSFETs or, due to their base current error compensation, even drive less expensive low beta bipolar transistors.
Since low power consumption has increasingly become a key requirement in TVs, austriamicrosystems has designed the AS3820/21 LED driver ICs using a unique power supply control technique that enables the best system efficiency. This power supply control technique is used in austriamicrosystems’ previously introduced LED drivers which are designed in by austriamicrosystems’ broad customer base of TV designers and manufacturers. The technique has been further improved and requires fewer external components, provides fast response time, and direct control of the output voltage of any standard DC-DC converter. This direct control feature is especially useful for designing the latest 3D TVs.
In addition, austriamicrosystems’ AS3820 and AS3821 ICs utilize a totally new regulation concept which has no exposure to the high-voltage LED supply since no connection to the external transistor drain pin is required. This provides high flexibility regarding the maximum number of LEDs per string that can be driven and results in very high ESD robustness.
The devices are programmable via an SPI (serial peripheral interface) port and provide built-in safety features, including thermal shutdown and open and short LED detection. Other features include linear current setting using a 10-bit DAC, output slew rate programmability, H-Sync and V-Sync inputs to synchronize with a TV, direct PWM mode, undervoltage auto-turnoff, overvoltage auto-turnoff, temperature shutdown and fault interrupt output.
Availability and Pricing
The AS3820 and AS3821 LED driver ICs are available now in 0.5 mm pitch QFN and 0.8 mm pitch LQFP packages, with pricing starting at $1.80 in 1000s.
A demonstration board for the AS3820 and AS3821 is available.
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