LTC7871 Six-Phase, Synchronous Bidirectional Buck or Boost Controller FEATURES DESCRIPTION n Unique Architecture Allows Dynamic Regulation of The LTC 7871 is a high performance bidirectional buck or Input Voltage, Output Voltage or Current boost switching regulator controller that operates in either n Operates with External Gate Drivers and MOSFETs buck or boost mode on demand. It regulates in buck mode n V Voltages Up to 100V V Voltages Up to 60V from V -to-V and boost mode from V -to-V HIGH LOW HIGH LOW LOW HIGH n Synchronous Rectification: Up to 98% Efficiency depending on a control signal, making it ideal for 48V/12V n ADI-Proprietary Advanced Current Mode Control automotive dual battery systems. An accurate current pro- n 1% Voltage Regulation Accuracy Overtemperature gramming loop regulates the maximum current that can n Accurate, Programmable Inductor Current be delivered in either direction. The LTC7871 allows both Monitoring and Bidirectional Regulation batteries to supply energy to the load simultaneously by n SPI Compliant Serial Interface driving energy from either battery to the other. n Operation Status and Fault Report Its proprietary constant frequency current mode archi- n Programmable V , V Margining HIGH LOW tecture enhances the signal-to-noise ratio enabling low n Phase-Lockable Frequency: 60kHz to 750kHz noise operation and provides excellent current match- n Optional Spread Spectrum Modulation ing between phases. Additional features include an SPI- n Multiphase/Multi-ICs Operation Up to 24 Phases compliant serial interface, discontinuous or continuous n Selectable CCM/DCM/Burst Mode Operation mode of operation, OV/UV monitors, independent loop n Thermally Enhanced 64-Lead LQFP Package compensation for buck and boost operation, accurate n AEC-Q100 Qualification in Progress inductor current monitoring and overcurrent protection. The LTC7871 is available in a 64 pin 10mm 10mm APPLICATIONS LWEpackage. n Automotive 48V/12V Dual Battery Systems All registered trademarks and trademarks are the property of their respective owners. n Backup Power Systems TYPICAL APPLICATION High Voltage Bidirectional Controller with Programming and Monitoring Functions Boost-to-Buck Transition V HIGH 30V TO BUCK 2.2F VFB LOW 70V 3.01M 2.2 5V/DIV 12 OV LOW 10k 210k V EXTV LOW CC 10k OV HIGH 499k 2V/DIV + V 33F UV HIGH HIGH 12 I VFB L HIGH 90.9k 110k 5A/DIV V HIGH 48.7k 6.8H 1m 12.7k 10k V V 1F LOW HIGH PWM1 DRIVER 12V/180A 22F 2V/DIV 16.9k 1.5k 6 47pF 1nF 0.1F 0.1F V SW + LTC7060 LTC7871 100F 100V/DIV 6 0.1F 0.33F 499 499 1.69k 7871 TA01b + ITH SNSA1 HIGH 50s/DIV + SNSD1 PINS NOT USED ITH LOW SNS1 IN THIS CIRCUIT: IMON CLKOUT SS (PHASE 2 TO PHASE 5) DRVSET SETCUR MODE V HIGH DRVCC 45.3k ILIM V5 RUN 51k 100pF 4.7F 1m 6.8H PWMEN FAULT PWM6 DRIVER 37.4k PGOOD 0.1F 4.7F FREQ 16.9k 1.5k 0.1F 0.1F SGND LTC7060 BUCK BOOST BUCK SCLK 1.69k + SPI SDI SNSA6 + NOTE: SDO REQUIRES PULL-UP INTERFACE SDO SNSD6 CSB SNS6 7871 TA01a Rev. A 1 Document Feedback For more information www.analog.comLTC7871 TABLE OF CONTENTS Features ............................................................................................................................ 1 Applications ....................................................................................................................... 1 Typical Application ............................................................................................................... 1 Description......................................................................................................................... 1 Absolute Maximum Ratings ..................................................................................................... 3 Order Information ................................................................................................................. 3 Pin Configuration ................................................................................................................. 3 Electrical Characteristics ........................................................................................................ 4 Typical Performance Characteristics .......................................................................................... 8 Pin Functions .....................................................................................................................10 Block Diagram ....................................................................................................................12 Operation..........................................................................................................................13 Applications Information .......................................................................................................20 Serial Port ............................................................................................................................................................. 31 Serial Port Register Details ................................................................................................................................... 35 Typical Applications .............................................................................................................47 Package Description ............................................................................................................48 Revision History .................................................................................................................49 Typical Application ..............................................................................................................50 Related Parts .....................................................................................................................50 Rev. A 2 For more information www.analog.com