QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 501 Universal High Input Voltage 12V/6A POWER SUPPLY LTC3703 DESCRIPTION

Transcription

1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 50 Universal High Input Voltage V/6A POWER SUPPLY LTC70 DESCRIPTION Demonstration circuit 50 is high power, high voltage, and high efficiency DC/DC buck converter featuring the LTC70. This is a general-purpose high voltage DC to DC with an input voltage range of 0V to 7V. The board is optimized for positive 8V input operation with high voltage surges up to 7VDC allowed. The limiting factor is the LTC70 GN6 package that will not meet UL/CSA/IEC60950 clearance and creepage distance requirements above the SELV 60VDC maximum due to pin spacing. If the user wishes to support higher continuous input voltages or compliance to 60950, the LTC70 is offered in a G-8 pin package. See Data Sheet. However, for the purposes of evaluation, the board will work reliably up to 7V. The maximum continuous current in free air is A. 6A is permissible with some forced air cooling. The output voltage is programmed with a voltage divider and configured for V. The demonstration circuit comes with jumpers preset to power up in the continuous switching mode. Test points are provided to monitor or control Mode/SYNC, BGRTN and VCC. Configuration jumpers allow Burst or Continuous Switch mode operation (JP), to turn the power supply On and OFF (JP) and Vcc or Boost Bias Supply select (JP). The board has been layed out to support up to A of DC current buy doubling the MOSFETs and input capacitors along with an inductor with lower DC resistance and higher current ratings. Some forced air cooling will be required. Special consideration must be given to the inductor chosen. The short circuit current has a very wide tolerance with initial transient spikes that work against the use of a Ferrite based inductor. A powder based magnetic core material is highly recommended. Whatever inductor is chosen, the circuit should be checked for proper short circuit operation by verifying the inductor does not saturate. The board can also support a boost converter configuration. See schematic. Design files for this circuit board are available. Call the LTC factory. Table. Performance Summary PARAMETER CONDITION/NOTES VALUE Maximum Input Voltage Limited by MOSFET Voltage Ratings. 7V ±0 % Minimum Input Voltage 0V ±0 % Efficiency Vin = 8V with amp load Vin = V with amp load 9% 95% Switching Frequency User adjustable. 60KHz Nominal Output Voltage 0 to 6 Amps measured at VOUT and GND terminals. V ± % Maximum Current Free Air Limited by temperature rise of inductor. A Maximum Current with Force Air cooling Accuracy and limit set by Rds-on value of bottom MOSFET. See Datasheet. 6A 0A / +A

2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 50 Universal High Input Voltage V/6A POWER SUPPLY QUICK START PROCEDURE Demonstration circuit 50 is easy to set up to evaluate the performance of the LTC70. Refer to Figure for proper measurement equipment setup and follow the procedure below:. Connect a power source to the VIN and GND. The power supply must be capable of at least 0 watts of power at the input voltage you choose provided it is within the Vin range permitted.. Connect a load to the VOUT and GND terminals and set it to 0Amps. Turn on the input power supply and DC50 should power up.. Adjust load as required for evaluation. Figure. Proper Measurement Equipment Setup

3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 50 Universal High Input Voltage V/6A POWER SUPPLY

4 5 5 D D C C B B A A 5 SW GND FB VIN SHDN MODE/SYNC FSET COMP FB IMAX INV RUN/SS GND BGRTN BG DRVCC VCC SW TG BOOST VIN

5 Linear Technology Corporation LTC70EGN Bill Of Material Demo Bd. #50A Item Qty Reference Part Description Manufacture / Part # //005 CIN,CIN Cap., X7R uf 00V 0% TDK C5X7RA05M 0 CIN,CIN (Opt) Cap., X7R uf 00V 0% TDK C5X7RA05M CIN5 Cap., Alum 68uF 00V 5% SANYO 00MV68AX 0 CIN6 (Opt) Cap., Alum 68uF 00V 5% SANYO 00MV68AX 5 COUT Cap., Alum 70uF 6V 0% OSCON 6SP70M 6 0 COUT (Opt) Cap., Alum 70uF 6V 0% OSCON 6SP70M 7 COUT,COUT Cap., X7R 0uF 6V 0% Taiyo Yuden EMK5BJ06KN 8 0 COUT5 (Opt) Cap., X7R 0uF 6V 0% Taiyo Yuden EMK5BJ06KN 9 CSS,C,C Cap., X7R 000pF 00V 0% AVX 060C0KATA 0 CVCC Cap., Alum uf 5V 5% SANYO 5MVUAX C5,C Cap., X5R 0.uF 6V 0% Taiyo Yuden EMK07BJMA C Cap., NPO 70pF 5V 0% AVX 060A7KATA C6 Cap., X7R 0.uF 6V 0% Taiyo Yuden EMK07BJ0M C7 Cap., X5R uf 6V 0% Taiyo Yuden EMKBJ05MG 5 0 C8 (Opt) Cap., X7R 0.uF 6V 0% Taiyo Yuden EMK07BJ0M 6 C9 Cap., X7R 00pF 5V 0% AVX 060CMATA 7 0 C0 (Opt) Cap., X5R uf 6V 0% Taiyo Yuden EMKBJ05MG 8 0 C (Opt) Cap., NPO 0pF 5V 5% AVX 060AJATA 9 0 C (Opt) Cap., X5R.7uF 6.V 0% Taiyo Yuden JMKBJ75MG-T 0 0 C,C (Opt) Cap., 060 D Diode, Speed Switching Diodes Inc. BAS9-7 0 D (Opt) Schotkky Barrier Rectifier Diodes Inc. B00 D Schotkky Barrier Rectifier Diodes Inc. B00 - D Zener Diode, 8.V Diodes Inc. MMBZ57B D5 (Opt) Schottky Diode, 0V ZETEX ZHCS00 6 D6 Schottky Diode, Super-Mini Central Semi. Corp CMDSH- - LTC 7 D7 Zener Diode, V On Semi. MMBZ5B-7 8 JP,JP,JP Headers, Pins mm Ctrs. CommConn Con Inc. 80S-0G 9 XJ,XJ,XJ Shunt, Pins mm Ctrs. CommConn Con Inc. CCIJMM-8G 0 L Inductor, 7.8uH Vishay Dale IHLP-5050EZ-0-7R8-M Inductor, 8uH Sumida CDEP-8R0MC 0 L (Opt) Inductor, 0uH 00mA 0. Ohm murata LQHCN00K5 M,M Mosfet N-Chan., PowerPAK SO8 Vishay Siliconix Si785DP 0 M,M Mosfet N-Chan., PowerPAK SO8 Vishay Siliconix Si785DP Q XSTR,, DARLINGTON Zetex FZT600TA 5 R,R6 Res., Chip W 5% AAC CR6-0JM 6 6 R,R,R9-R,R Jumper, Chip 0 Ohm /6W 5% AAC CJ06-000M Page - of -

6 Linear Technology Corporation LTC70EGN Bill Of Material Demo Bd. #50A Item Qty Reference Part Description Manufacture / Part # //005 7 R Res., Chip 8.0K 0.W % AAC CR6-80FM 8 R5,R8 Res., Chip 0K 0.W 5% AAC CR6-0JM 9 R6 Res., Chip 0 0.W 5% AAC CR6-00JM 0 R7 Res., Chip 8.06K 0.W % AAC CR6-806FM R8 Res., Chip.K 0.W % AAC CR6-FM 0 R,R5 (Opt) Res., 060 R Res., Chip K 0.W % AAC CR6-FM R7 Res., Chip W 5% AAC CR8-0JM 5 0 R9 (Opt) Res., Chip 07K 0.W % AAC CR6-07FM 6 0 R0 (Opt) Res., Chip 0K 0.W 5% AAC CR6-0JM 7 0 R (Opt) Res., Chip.K 0.W % AAC CR6-FM 8 9 TP-TP9 Turret, Testpoint Mill Max 50- (sealed bags) 9 U I.C., Step-Down Reg. Linear Tech. Corp. LTC70EGN 50 0 U (Opt) I.C., DC/DC Converter Linear Tech. Corp. LT6CS5 5 SCREW, #-0, /" ANY (sealed bags) 5 STANDOFF, #-0 /" MICRO PLASTICS HTSP0 (sealed) 5 PRINTED CIRCUIT BOARD DEMO CIRCUIT 50A 5 STENCIL(Top & Bottom) STENCIL DC50A Page - of -