AMSCO AS3694

AS3694
Product Brief
AS3694
Product Brief
12 channel high precision LED driver for LCD backlight and
3 DCDC Step Up controller
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1 General Description
The AS3694 is a 12 cannels high precision LED
driver with build in PWM generators for building
backlight panels in LCD-TV-sets. 3 DCDC Step Up
controllers can be used to build the power supplies
for red, green and blue LED strings.
External clock and synchronizing inputs allow the
synchronization of the LCD backlight with the TV
picture. Local dimming and scan dimming is
supported by 12 independent PWM generators with
programmable delay, period and duty cycle. Three
free configurable dynamic power feedback circuits
make the device usable for white LED as well as
RGB backlights. Build in safety features include
thermal shutdown as well as open and short LED
detection. All circuit parameters are programmable
via I2C or SPI interface.
2 Key Features
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12 independent LED channels
Output current 70mA
Output voltage up to 50V
Absolute current accuracy ±0.5%
www.austriamicrosystems.com (mpa)
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Output slew rate limited to reduce EMI
Current programmable with external resistor
12 independent PWM generators with 12 bit
resolution
H-Sync, F-Sync inputs to synchronize with TVset
Three independent power feedback for R-, G-,
B-supply regulation
Build in 5V shunt regulator
I2C or SPI interface with 6 bit address
Fault interrupt output
Open LED detection
Short LED detection
Temperature shutdown
3 DCDC Step Up controller
ƒ Current mode
ƒ Efficiency > 90%
ƒ Input voltage range 15V to 50V
ƒ Output voltage up to 50V / 200mA
Package epTQFP64
3 Application
LED Backlighting for LCD – TV Sets and Monitors
Revision 1.1 / 2007-11-25
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AS3694
Product Brief
Block Diagram
V2_5
REF
FBR
Vsupply
V_BLUE
BOOST
GREEN
BOOST
BLUE
FBB
SMPS
feedback
Vsupply
V_RED
FBR
FBG
Vreg
Vsupply
V_GREEN
FBG
FBB
Vsupply
BOOST
RED
Fault detectors
Reference,
DAC
PWM
PWM
PWM
PWM
AS3694
PWM
PWM
PWM
PWM
86 byte
registers
www.austriamicrosystems.com (mpa)
PWM
Addr1
Addr2
SDO
CS
SCL
SPI / I2C
Interface
SDA
Hsync
Vsync
GND
PWM
PWM
Revision 1.1 / 2007-11-25
Fault
PWM
V2_5
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AS3694
Product Brief
Copyright
Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, AustriaEurope. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted,
merged, translated, stored, or used without the prior written consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Diclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions
appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by
description regarding the information set forth herein or regarding the freedom of the described devices from
patent infringement. Austriamicrosystems AG reserves the right to change specifications and prices at any time
and without notice. Therefore, prior to designing this product into a system, it is necessary to check with
austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applications requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-support
or lifesustaining equipment are specifically not recommended without additional processing by
austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might
show deviations from the standard production flow, such as test flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not
limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect,
special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing,
performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise
or flow out of austriamicrosystems AG rendering of technical or other services.
Contact Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstätten, Austria
T. +43 (0) 3136 500 0
F. +43 (0) 3136 5692
For Sales Offices, Distributors and Representatives, please visit:
http://www.austriamicrosystems.com/contact
www.austriamicrosystems.com (mpa)
Revision 1.1 / 2007-11-25
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