DEMO CIRCUIT 1329 LTC4352 QUICK START GUIDE LTC4352 Low Voltage Ideal Diode Controller with Monitoring DESCRIPTION Demonstration circuit 1329 showcases the Design files for this circuit board are available. LTC4352, a Low Voltage Ideal Diode Controller w/ Call the LTC factory. Monitoring, in a DFN-12 package. The LTC4352 L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, creates a near-ideal diode using external N- DirectSense, Easy Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode Dimming, No Latency , No Latency Delta-Sigma, No channel MOSFET therby replacing high power R , Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SENSE Schottky diode and associated heat sink. Ideal di- SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names may be trade- odes enable low loss power ORing and supply marks of the companies that manufacture the products. holdup applications. PERFORMANCE SUMMARY Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Operating Range 2.9 18 V IN With External 2.9V to 4.7V V Supply 0 V CC CC With External 4.7V to 6V V Supply 0 CC 18 I Output Load Current 0 10 A OUT V V External Supply Range V < V 2.9 6 V CC(EXT) CC IN CC V V Internal Regulator Voltage 3.4 4.1 4.6 V CC(INT) CC V Forward Regulation Voltage (V V ) 10 25 40 mV FWD(REG) IN OUT OPERATING PRINCIPLES The LTC4352 regulates the forward voltage drop Undervoltage and overvoltage protection (not used across the external MOSFET to ensure smooth in the demo board circuit) allows the controller to current transfer in diode-OR applications. A fast operate in a restricted input voltage range. turn-on reduces the load voltage droop during The controller features an open MOSFET detect supply switch-over. If the input supply fails or is circuit that flags excessive voltage drop across the shorted, a fast turn-off minimizes reverse current. pass transistor in the on state. The controller operates with rail voltages from 2.9v The STATUS pin signal (green LED) indicates the to 18V. Operation with rail voltages below 2.9V re- MOSFET on state, and the FAULT pin signal (red quires additional supply on V from 2.9V to 6.0V. CC LED) indicates an undervoltage, overvoltage or open MOSFET fault. 1 L TC4352 QUICK START PROCEDURE Demonstration circuit 1329 is easy to set up to these pins set the overvoltage and undervolt- evaluate the performance of the LTC4352. Refer to age levels. Error Reference source not found. for proper 7. Place jumper JP1 in the HIGH position. Ap- measurement equipment setup. The DC1329 in- ply 5VVIN1. Measure voltage between VIN1 cludes two identical but separate circuits. In the and VOUT1 turrets with no load. The voltage sample test procedure below, each circuit tested should be lower than 1mV. Replace JP1 to as a single ideal diode (described for top-half cir- LOW position. cuit 1) and after that both circuit are tested for 8. With VIN1=5V apply 10A electronic load be- OR-ing operation with a common load. tween VOUT1 and GND. Measure VIN1- VOUT1 voltage, it should be between 40mV Ideal Diode Test. and 60mV. 1. Place jumper JP1 (REV1) in the LOW posi- 9. With VIN1=5V connect a 9V alkaline bat- tion terys negative terminal to GND and the posi- tive terminal to VOUT1. The STATUS green JP1 (REV1) LOW LED will turn off, as the circuit is preventing 2. Adjust lab power supply output voltage to reverse current from flowing. 2.9V. Place voltmeters to measure DC1329 input voltage (Vin1), voltage between VIN1 and VOUT1 turrets (Vin1-VOUT1), and VCC1 Ideal Diode-ORing Test. voltage. Turn switch SW1 on to apply 2.9V to 10. Adjust both supplies output voltage to 5V. the board. The STATUS green LED should Turn both switches SW1 and SW2 on. In the light. case when only one ideal-diode is on, slightly 3. Increase the input voltage from 2.9V up to increase the output voltage of the supply op- 17V and observe that voltage between VIN1 erating in the off channel to have both chan- and VOUT1 is the Forward Regulation Volt- nels on. If both channels are on, slightly age of 25mV15mV, the voltage at the VCC1 change the output voltage of one supply to turret follows closely below the input voltage check that one ideal-diode channel will be off from 2.9V up to 4.1V, and regulates to 4.1V when difference between input voltages ex- with higher input voltages. The STATUS LED ceeds difference between forward regulation should stay green. voltages (25mV15mV). 4. Adjust the board input voltage to +5.0V. Connect one terminal of a test lead to the 11. Adjust both supplies output voltage to 5V. GND turret and other to the UV pin (pin 3). Turn both switches SW1 and SW2 on. Make The FAULT red LED should light and STATUS both channels on as described in paragraph green LED goes off. 11. Apply a common load of 10A. Slightly 5. Connect one terminal of the test lead to the change the output voltage of one supply to VIN1 turret and other to the OV pin (pin4). check that one ideal-diode channel will be off The FAULT red LED should light and STATUS when difference between input voltages ex- green LED goes out. ceeds sum of difference between forward regulation voltages and difference between 6. Note: The UV and OV pin thresholds are voltage drops in the MOSFET and traces. 500mV +/-10mV. Appropriate dividers on 2