QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 620 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATORS FOR TFT-LCD PANELS

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1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 60 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATORS FOR TFT-LCD PANELS DESCRIPTION LT94 Demonstration circuit 60 is a quad output power supply intended for use in large TFT-LCD panels. The circuit features the LT 94 high current quad-output switching regulator and generates a.v logic supply along with the triple output supply required for the TFT-LCD panels. With an input voltage range of 8V to 0V, a step down regulator provides.v VLOGIC with up to A current; a high power SEPIC converter, a lower power boost converter and an inverting converter provide three independent output voltages AV DD, VON and VOFF required by the LCD panels. A high side PNP provides delayed turn on of the VON signal and can source up to 0mA at 0V. All four switchers are synchronized to the internal.mhz clock, allowing the use of low profile inductors and ceramic capacitors. They all have softstart to limit start-up inrush current. Long wires run from input sources (such as wall adaptors) can cause large voltage spikes during initial plug-in. C7 is installed on DC60 to damp the possible voltage spikes. C7 is not required for applications when input source is close to the regulator. Please refer to Application Note 88 for details. Design files for this circuit board are available. Call the LTC factory. LT is a registered trademark of Linear Technology Corporation Table. Performance Summary (T A = 5 C unless otherwise noted) PARAMETER CONDITION VALUE Minimum Input Voltage -40 C to 85 C 8V Maximum Input Voltage -40 C to 85 C 0V Output Voltage V LOGIC V IN = 8V to 0V, I OUT = 0A to A.V ±% Maximum Output Current at V LOGIC V IN = 8V to 0V (Note ) A Typical Output Ripple V LOGIC V IN = V, load at V LOGIC = A (0MHz BW) mv P P Typical Output Ripple AV DD V IN = V, load at AV DD = 500mA (0MHz BW) 64mV P P Typical Switching Frequency On/Off Control Logic Low Voltage-Off, -40 C to 85 C Logic High Voltage-On.MHz 0.4V MAX.4V MIN Note : A maximum output current is guaranteed when V OFF is unloaded. Since V OFF is supplied from V LOGIC, the load at V OFF reduces the available current at V LOGIC. More output current is available at higher input voltage. Please refer to the LT94 data sheet for output current vs. input voltage curve. QUICK START PROCEDURE Demonstration circuit 60 is easy to set up to evaluate the performance of the LT94. Refer to Figure for proper measurement equipment setup and follow the procedure below: NOTE: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage ripple by touching the

2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 60 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATORS FOR TFT-LCD PANELS probe tip directly across the V IN or V OUT and terminals. See Figure for proper scope probe technique.. Make sure the input voltage does not exceed 0V. With power off, connect the input power supply to V IN and.. Turn on the power at the input.. Check for the proper output voltages. If there is no output, temporarily disconnect the load to make sure that the load is not set too high. 4. Once the proper output voltages are established, adjust the loads within the operating range and observe the output voltage regulation, ripple voltage, efficiency and other parameters. Figure. Proper Measurement Equipment Setup VIN Figure. Measuring Input or Output Ripple

3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 60 HIGH CURRENT QUAD OUTPUT SWITCHING REGULATORS FOR TFT-LCD PANELS

4 5 4 D C B Voff -0V@50mA RUNSS Vlogic.V@A * E C6.uF 0V E5 E7 C4 0pF R 80.6K C4 0.05uF C6 uf 0V D6 ZHCS400 R4 D ZHCS400 R 6.K C uf 6.V R C7 0.47uF 6V C5 0.05uF C9 opt. D CMDSH- L 4.7uH Vin 8-0V L4 0uH D B0A E C 0.uF 0V C0 00pF C 0uF 5V U LT94EFE SW4 NFB4 FB4 RUNSS SS4 BIAS BOOST SW SW FB + C7 47uF 5V VC 5 6 VIN VIN SW VC R0 C 8K R 00pF 6.8K C C 00pF 00pF R 7K C 680pF VC 9 L 0uH L6 uh SW SW FB PGOOD CT VON E FB S VC4 C R K 00pF C4 00pF C 00pF C6.0uF 5V L 0uH D5 B40A R4 opt. R9 K R8 C8 opt. R6 95.K R5 C uF C0.uF 5V C8 0uF 6V R5 00K C5 0.47uF 5V E C5 uf 6V E4 E6 AVdd V@500mA PGOOD Von 0V@0mA D C B E8 E9 A E0 E * Voff unloaded CONTRACT NO. APPROVALS DATE DRAWN June Wu 0//0 TITLE CHECKED APPROVED ENGINEER Gary Shockey 0//0 DESIGNER TECHNOLOGY 60 McCarthy Blvd. Milpitas, CA 9505 Phone: (408)4-900 Fax: (408) LT94EFE, High Current Quad Output Switching Regulator For TFT-LCD Panels SIZE CAGE CODE DWG NO REV DC60A A A Friday, September, 00 SCALE: FILENAME: SHEET OF 5 4

5 Linear Technology Corporation LT94EFE Bill Of Material Demo Bd. #60A Item Qty Reference Part Description Manufacture / Part # 6/7/005 C CAP., X5R, 0uF, 5V, 0% 0 Taiyo Yuden, TMK5BJ06MM C8 CAP., X5R, 0uF, 6V, 0% 0 Taiyo Yuden, EMK5BJ06MN C CAP., X5R, uf, 6.V, 0% 06 Taiyo Yuden, JMK6BJ6ML 4 C CAP., X7R, 0.uF, 0V, 0% 060 AVX, 060ZC4MATA 5 C5,C4 CAP., X7R, 0.05uF, 6V, 0%, 040 AVX, 040YC5MATA 6 C6 CAP., X7R,.uF, 0V, 0% 0805 MuRata, GRMBR7A5KA0L 7 C7 CAP., X5R, 0.47uF, 6V, 0% 060 AVX, 060YD474MATA 8 C9 CAP., X5R, 0.047uF, 6V, 0% 040 AVX, 040YD47KATA 9 C0 CAP., X5R,.uF, 5V, 0% 0 Taiyo Yuden, GMK5BJ5MN 0 C,C,C4 CAP., X7R, 00pF, 50V, 0% 040 AVX, 0405CMATA C CAP., X7R, 680pF, 50V, 0% 040 AVX, 0405C68MATA C5 CAP., X5R, 0.47uF, 5V, 0% 0805 Taiyo Yuden, GMKBJ474MG C6 CAP., X5R,.0uF, 5V, 0% 0805 AVX, 0805D05KATA 4 C7 CAP., TANT, 47uF, 5V, 0% 74 AVX, TAJE476M05R 5 4 C0-C CAP., X7R, 00pF, 50V, 0%, 040 AVX, 0405C0MATA 6 0 C8,C9 (OPT.) CAP., C4 CAP., NPO, 0pF, 50V, 0% 040 AVX, 0405A00KATA 8 C5 CAP., X5R,.0uF, 6V, 0% 0805 TAIYO YUDEN, EMKBJ05MG 9 C6 CAP., X7R,.0uF, 0V, 0% 0805 TAIYO YUDEN, LMKBJ05MG 0 D Schottky Barrier REC., B0A SMA Diodes Inc., B0A D Schottky Diode, CMDSH- SOD- CENTRAL SEMI., CMDSH--LTC D,D6 Schottky Barries Dio., ZHCS400, SOD- ZETEX, ZHCS400 D5 Schottky Barrier REC., B40A SMA Diodes Inc., B40A 4 E-E TURRET, MILL-MAX, 50-5 L INDUCTOR, 4.7uH RLF700 TDK, RLF700T-4R7MR4 6 L,L INDUCTOR, 0uH SLF608 TDK, SLF608T-00MR 7 L4 INDUCTOR, 0uH RLF508 TDK, RLF508T-00MR94 8 L6 INDUCTOR, uh RLF508 TDK, RLF508T-0MR5 9 R0 RES., CHIP, 8K, /6W, 5% 040 AAC, CR05-8JM 0 R RES., CHIP, 6.8K, /6W, 5% 040 AAC, CR05-68JM 4 R,R5,R8,R4 RES., CHIP,, /6W, % 040 AAC, CR05-00FM R RES., CHIP, 7K, /6W, 5% 040 AAC, CR05-7JM R RES., CHIP, K, /6W, 5% 040 AAC, CR05-JM 4 R RES., CHIP, 6.K, /6W, % 040 AAC, CR05-6FM 5 R RES., CHIP, 80.6K, /6W, % 040 AAC, CR05-806FM 6 R6 RES., CHIP, 95.K, /6W, % 040 AAC, CR05-95FM Page - of -

6 Linear Technology Corporation LT94EFE Bill Of Material Demo Bd. #60A Item Qty Reference Part Description Manufacture / Part # 6/7/005 7 R9 RES., CHIP, K, /6W, % 040 AAC, CR05-FM 8 R5 RES., CHIP, 00K, /6W, 5% 060 AAC, CR6-04JM 9 0 R4 (OPT.) RES., CHIP, U (Tape & Reel) I.C.LT94EFE, TSSOP8FE LINEAR., LT94EFE 4 PRINTED CIRCUIT BOARD DEMO CIRCUIT #60A Page - of -