DC to DC Power Supplies (Converters)
Quad DC/DC Converter is suited for TFT LCDs.
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Press Release Summary:
Packaged in 4 x 4 mm QFN, LT1942 integrated quad switching regulator provides necessary power supply functions for 2-7 in. TFT LCD panels and their white LED backlighting. It operates from input voltage of 2.6-16 V and has 1 MHz switching frequency. Incorporating 2 boost and one inverting DC/DC converters as well as Schottky diodes, product also features programmable power sequencing, independently set TFT supply output voltages, and soft-start.
Original Press Release:
Quad DC/DC Converter for Triple Output TFT Supply and LED Backlighting
Milpitas, CA - December 9, 2004 - Linear Technology Corporation announces the LT1942, a highly integrated quad switching regulator designed to provide all necessary power supply functions for TFT displays and their required white LED backlighting. The LT1942, packaged in a 4mm x 4mm QFN was designed to power 2" to 7" TFT-LCD panels in applications ranging from PDAs to automotive GPS displays. It operates from an input voltage range of 2.6V to 16V, making it ideal for applications ranging from Li-Ion powered handhelds to automotive applications. Its 1MHz switching frequency provides low noise operation by keeping external components tiny and providing a compact solution footprint and profile.
The TFT supply incorporates two boost and one inverting DC/DC converters. The TFT supply output voltages are independently set, unlike charge pump solutions which have several limitations, enabling greater flexibility in TFT-LCD designs. In order to make the solution as compact as possible, schottky diodes have been integrated into the device. Additional features include programmable power sequencing, soft-start, power good and output disconnect.
The LED driver is a boost DC/DC converter that can be independently controlled. The LED driver has built-in dimming control for precise control of LED current. An 8:1 dimming range is achieved by adjusting the control voltage. The user can elect to drive a single string (6 LEDs) or two strings of LEDs (12 LEDs). An LED ballast circuit is included to precisely match the LED currents if two strings of LEDs are used. Both soft-start and open LED protection are built into the LED driver.
The LT1942 is available in a 4mm x 4mm QFN-24 available from stock. Pricing starts at $2.75 each for 1,000-piece quantities.
Summary of Features: LT1942
Triple Output TFT Supply with Built-In Power Sequencing
Integrated White LED Backlight Driver
Integrated Schottky Diodes
Active Ballast Circuitry Ensures Precise Current Matching in White LEDs
Low Noise 1MHz Fixed Frequency Operation
2.6V to 16V Input Voltage Range
Soft-Start Limits Inrush Current
TFT Supply Output Voltages Independently Set
Power Good and Output Disconnect for TFT Supply
Built-In LED Dimming Capability
Open LED Protection for LED Driver
24-Lead (4mm x 4mm x 0.75mm) QFN Package
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include high performance amplifiers, comparators, voltage references, monolithic filters, linear regulators, DC-DC converters, battery chargers, data converters, communications interface circuits, RF signal conditioning circuits, and many other analog functions. Applications for Linear Technology's high performance circuits include telecommunications, cellular telephones, networking products such as optical switches, notebook and desktop computers, computer peripherals, video/multimedia, industrial instrumentation, security monitoring devices, high-end consumer products such as digital cameras and MP3 players, complex medical devices, automotive electronics, factory automation, process control, and military and space systems.
Note: LT, LTC and Burst Mode are registered trademarks of Linear Technology Corp.
Worldwide Contacts
North America
John Hamburger
Tel: (408) 432-1900 ext. 2419
jhamburger@linear.com
Doug Dickinson
Tel: (408) 432 1900 ext. 2233
ddickinson@linear.com
China (PRC)
Fanny Lau
Tel: 852-2428-0303
flau@linear.com
Angela Ao
Tel: (8610)6522 8081
angela@eba.com.cn
Germany
Ralf Stegmann
Tel: +49 (0) 7131/9234-0
ralf@ezwire.com
Japan
Kazuto Takahashi
Tel: 81-3-5226-7291
takahashi@linear-tech.co.jp
UK & Scandinavia
Alan Timmins
Tel: +44-1-252-629937
a.timmins@ntlworld.com
Korea
Desiree Park
Tel: +82 (0) 2812 1144
desiree@ezwire.com
