High-Current Quad Output Regulator Protects Large TFT Panels

Feb. 16, 2004

Optimal protection for large thin-film-transistor (TFT) flat-panel displays (FPDs), 22 in. in diameter and larger, is now a possibility with the LT1493. Linear Technology's high-current quad output adjustable switching regulator features an input range of 4.5 to 22 V, delivering independent outputs for V_LOGIC, A_DD, V_ON, and V_OFF signals as required by TFT FPDs. The IC contains a 2.4-V buck regulator to power V_LOGIC, a 2.6-A boost regulator to drive the TFTs, a high-voltage TFT biasing output, and a 0.4-A inverter for negative TFT biasing.

The LT1493 operates at 1.2 MHz. A Panel Protect feature disables the V_ON signal if any of the four outputs are more than 10% below the normal reset output-voltage level. This prevents the TFT panel from being exposed to an onrush of V_ON current that would essentially "flash light" and damage the entire FPD. A high-side pnp transistor provides a delayed turn-on of the V_ON signal, which has up to 30 mA of bias current, to ensure that it comes on only after all the other outputs are powered up.

A PGOOD output signal drives an optional PMOS pass device to provide an output disconnect for the A_DD output. A soft-start feature is also available for all channels.

Housed in a thermally enhanced TSSOP-28 package, the IC costs $4.75 each in 1000-unit quantities.

Linear Technology Corp. www.linear.com (408) 432-1900

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About the Author

Roger Allan

Roger Allan is an electronics journalism veteran, and served as Electronic Design's Executive Editor for 15 of those years. He has covered just about every technology beat from semiconductors, components, packaging and power devices, to communications, test and measurement, automotive electronics, robotics, medical electronics, military electronics, robotics, and industrial electronics. His specialties include MEMS and nanoelectronics technologies. He is a contributor to the McGraw Hill Annual Encyclopedia of Science and Technology. He is also a Life Senior Member of the IEEE and holds a BSEE from New York University's School of Engineering and Science. Roger has worked for major electronics magazines besides Electronic Design, including the IEEE Spectrum, Electronics, EDN, Electronic Products, and the British New Scientist. He also has working experience in the electronics industry as a design engineer in filters, power supplies and control systems.

After his retirement from Electronic Design Magazine, He has been extensively contributing articles for Penton’s Electronic Design, Power Electronics Technology, Energy Efficiency and Technology (EE&T) and Microwaves RF Magazine, covering all of the aforementioned electronics segments as well as energy efficiency, harvesting and related technologies. He has also contributed articles to other electronics technology magazines worldwide.

He is a “jack of all trades and a master in leading-edge technologies” like MEMS, nanolectronics, autonomous vehicles, artificial intelligence, military electronics, biometrics, implantable medical devices, and energy harvesting and related technologies.