SENSOR DRIVING LIGHTING

4 Channel High-Precision LED Controller for 3D-LCD Backlight with Integrated Step-Up Controller

The AS3834B is a 4 channel high precision LED controller with one PWM input for driving external bipolar transistors in LED backlight panels, also optimized for 2D and 3D operation in TV applications. The external PWM signal is automatically phase shifted and applied to all 4 channels in parallel, making the device perfect suitable for all kind of global dimming applications. 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.

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KEY FEATURES

• 4 channel LED controller
• 1 PMW input with phase shift
• Temperature supervision of external BJT
• 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%

AS3834B APPLICATIONS

• LED Backlighting for 3D-LCD Backlight TV Sets and Monitors

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AS3834B PRODUCT FACTS

Outputs [#]	4
LED current per output [mA]	270
Features	integrated step-up, 1 PWM input with phase shift, use of inexpensive BJTs with BETA compensation, LED string voltage only limited by BJT rating
Error detection	LED short/open with BJT temp. supervision
Read-back
LED-to-LED matching [%]	0.6
Supply voltage [V]	12-50
Package	SOIC28-1.27p