AS3834

austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: [email protected] Please visit our website at www.ams.com Technical coantmesntAsGtill valid Datasheet AS3834 4 channel high-precision LED controller for 3D-LCD backlight with integrated step-up controller 1 General Description The AS3834 is a 4 channel high precision LED controller with PWM inputs for driving external bipolar transistors in LCD-backlight panels, optimized for 2D and 3D operation. The integrated step-up controller provides the necessary output voltage for the LED string supply. The SMPS feedback control optimizes the power efficiency by adjusting the LED string supply voltage. Build in safety features include under-voltage and thermal shutdown as well as open and short LED detection. 2 Key Features 4 channel LED controller Step-up controller optimized for 2D/3D mode Supply voltage range: 12V to 50V Output current up to 270mA per channel Absolute current accuracy +/- 0.8% Channel to channel accuracy+/- 0.6% 4 separated PWM inputs Open LED detection and disconnect Short LED protection and auto-turnoff Undervoltage shutdown Temperature shutdown Temperature supervision of external BJT BJT Beta compensation SMPS feedback control DCDC Softstart Function Over Voltage Protection (OVP) Package SOIC-28, TQPF-32 Package Figure 1....