DEMO MANUAL DC1926A Dual Ideal Diode Controller DESCRIPTION Demonstration circuit 1926A features the LTC4353, a dual low voltage ideal diode controller, in a typical 12A application. The LTC4353 creates two near-ideal diodes using external N-channel MOSFETs thereby replacing high power Schottky diodes and their associated heat sinks. Ideal diodes enable low loss power ORing and supply holdup applications. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY Specifications are at TA = 25°C SYMBOL PARAMETER CONDITIONS MIN VIN VIN1 and VIN2 Input Voltage Operating Range With External VCC Supply 2.9 0 VIN1, VIN2 ≤ VCC 2.9 VCC(EXT) VCC External Supply Operating Range VCC(REG) VCC Regulated Voltage VCC(UVLO) VCC Undervoltage Lockout Threshold VCC Rising VFR Forward Regulation Voltage (VIN – VOUT) VIN =1.2V, VCC = 5V VIN =12V ΔVGATE MOSFET Gate Drive (GATE-VIN) IGATE TYP MAX UNITS 18 VCC V 6.0 V 4.5 5 5.5 V 2.3 2.55 2.7 V 2 2 12 25 25 50 mV mV VFWD = 0.2V; I = 0, –1μA; Highest VIN = 12V VFWD = 0.2V; I = 0, –1μA; Highest VIN = 2.9V 10 4.5 12 7 14 9 V V GATE1, GATE2 Fast Pull-Up Current GATE1, GATE2 Fast Pull-Down Current GATE1, GATE2 Off Pull-Down Current VFWD = 0.4V, ΔVGATE = 0, CPO=17V VFWD = –0.8V, ΔVGATE = 5V, Corresponding EN = 1V, ΔVGATE = 2.5V –0.9 0.9 65 –1.4 1.4 110 –1.9 1.9 160 A A μA VEN(TH) EN1, EN2 Threshold Voltage EN Falling 580 600 620 mV ΔVGATE(ON) MOSFET On-Detect Threshold (GATE-VIN) ONST Pulls Low 0.28 0.7 1.1 V IOUT Maximum Continuous Load Current for Si4126DY Limited by 0.6W power dissipation with maximum voltage regulation 50mV 12 A OPERATING PRINCIPLES The LTC4353 regulates the forward voltage drop across the external MOSFETs to ensure smooth current transfer in diode-OR applications. A fast turn-on reduces the load voltage droop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse current transients. The controller operates with rail voltages from 2.9V to 18V. Operation with rail voltages below 2.9V requires an additional supply of 2.9V to 6.0V at the VCC pin. The LTC4353 indicates the on state of each MOSFET with the ONST1 and ONST2 pin signals, when the gate voltage is at least 0.7V higher than VIN. Two enable pins (EN1, EN2) allow activating or blocking each MOSFET channel individually. Green LEDs ON1 and ON2 indicate the state of the associated MOSFET. dc1926af 1 DEMO MANUAL DC1926A QUICK START PROCEDURE Demonstration circuit DC1926A is easy to set up to evaluate the performance of the LTC4353. Controller performance can be verified over the full operating range of 2.9V to 18V. Ideal Diode Test 1. Connect a 12V power supply to VIN1(+) and GND (–) of the DC1926A. Place a millivoltmeter between the input (VIN1) and output (OUT1) turrets (refer to the diagram of Figure 1). This is the controller regulation voltage. The regulation voltage should be in the range of 2mV to 50mV. The installed MOSFETs in the SO-8 package are located on the top side of the board. Provision is made on the bottom side for using an additional SO-8 MOSFET in parallel with the MOSFET on the top side. To extend current capability the unstuffed PCB footprint (bottom side) also supports the D2PAK package. 2. LED1 should be illuminated. 3. Repeat the test with the second channel (VIN2, OUT2). The DC1926A test includes two parts: Ideal Diode Test and Ideal Diode-ORing test. 4. Record regulation voltage values. mV + POWER SUPPLY 12V – Figure 1. Ideal Diode Regulation Voltage Measurement dc1926af 2 DEMO MANUAL DC1926A QUICK START PROCEDURE Ideal Diode-ORing Test 1. Connect two identical power supplies adjusted to +12V to VIN1 and VIN2 inputs and provide a load to the parallel connected OUT1 and OUT2 turrets (refer to the diagram of Figure 2). The output load current should not exceed 12A for continuous operation. 2. The steady state operation of the Ideal Diode ORing circuit is defined by the following parameters: –VDS(ON) is the voltage drop of the MOSFET RDS(ON) under maximum load current. This is measured by using only the power supply of the channel under test with the load connected and the measurement between VIN and OUTPUT. Record VDS(ON); –ΔVREG is the absolute value of the differences in voltage recorded in step 4 above; –ΔSUPPLIES is the difference of the power supply output voltages. 3. Adjust the voltage of the power supply connected to [ΔSUPPLIES-ΔVREG] > VDS(ON) > 0. The power supply will provide all of the current to the load. The LED associated with this channel will be illuminated 4. Adjust the voltage of the power supply to VDS(ON) > [ΔSUPPLIES-ΔVREG] > 0. The supply with the higher voltage will supply most of the current to the load, while the supply with the lower voltage will supply less current. Both LEDs diodes will be illuminated because both channels are providing current to the load. + POWER SUPPLY 1 12V – REGULATED LOAD – POWER SUPPLY 2 12V + Figure 2. Ideal Diode ORing Operation dc1926af 3 DEMO MANUAL DC1926A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 1 1 CVCC Cap., X7R, 0.1μF 50V 10%, 0805 AVX, 08055C104KAT2A 2 2 C1, C2 Cap., X7R, 0.056μF 50V 10%, 0805 AVX, 08055C563KAT2A 3 2 D1, D2 LED, GREEN Panasonic, LN1351C-TR 4 2 D3, D4 Diode, Current Limiting, 3.2V, SOD-80 Central Semi. Corp., CMJ3500-TR 5 9 E1-E9 Turret, 0.064" Mill Max, 2308-2-00-80-00-00-07-0 6 6 J1, J2, J3, J4, J5, J6 Connector, Banana Jack Keystone, 575-4 7 2 M1, M2 MOSFET, N-Channel, 30V, SO8-POWERPAK Vishay, Si4126DY 8 2 R3, R5 Resistor, Chip 10k 0.1W 5%,0805 Vishay, CRCW080510K0JNEA 9 0 R4, R6 Resistor, 0805 TBD 10 1 U1 I.C., Dual Ideal Diode, DFN16DE-4 × 3 Linear Technology, LTC4353IDE dc1926af 4 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. D C B A GND VIN2 18V MAX EN2 EN1 VCC VIN1 18V MAX 1 E8 J5 E7 J4 E5 E2 E3 E1 J1 1 R5 10K R3 10K R4 OPT R6 OPT VIN2 1 2 EN2 3 NC NC 15 17 GND EP VCC EN1 4 6 50V C2 0.056uF VIN2 CPO2 VIN1 CPO1 CUSTOMER NOTICE CVCC 0.1uF 14 16 13 0.056uF 50V C1 11 U1 LTC4353IDE VIN1 M2 Si4126DY GATE2 5 GATE2 OUT2 ONST2 ONST1 OUT1 GATE1 12 GATE1 M1 Si4126DY 3 2 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. D4 CCLM3500 ONST2 ONST1 1 REV D3 CCLM3500 __ ECO 4 2 2 (GREEN) ON2 D2 LN1351C-TR 1 (GREEN) ON1 D1 LN1351C-TR 1 1ST PROTOTYPE DESCRIPTION SCALE = NONE DATE: N/A SIZE DATE OUT2 GND OUT1 12-09-11 DEMO CIRCUIT 1926A LTC4353IDE 4 12/09/2011, 09:36 AM IC NO. 5 SHEET 1 1 REV. OF 1 DUAL IDEAL DIODE CONTROLLER TITLE: SCHEMATIC TECHNOLOGY E9 J6 E6 J3 E4 J2 VLADIMIR O. 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only 1. ALL RESISTORS AND CAPACITORS ARE 0805. 5 APPROVED REVISION HISTORY NOTE: UNLESS OTHERWISE SPECIFIED OUT2 APPROVALS 7 8 9 10 OUT1 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. KIM T. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APP ENG. VLADIMIR O. APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 2 D C B A DEMO MANUAL DC1926A SCHEMATIC DIAGRAM dc1926af 5 DEMO MANUAL DC1926A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1926af 6 Linear Technology Corporation LT 0812 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2012