Datasheet LT8228 (Analog Devices)

LT8228 Bidirectional Synchronous 100V Buck/Boost Controller with Reverse Supply, Reverse Current and Fault Protection
FEATURES DESCRIPTION
n
Bidirectional Voltage or Current Regulation
The LT®8228 is a 100V bidirectional constant-current or n
Bidirectional Reverse Current Protection
constant-voltage synchronous buck or boost controller n
Input and Output Negative Voltage Protection to –60V
with independent compensation network. The direction of n
Bidirectional Inrush Current Limit and Boost Output
the power flow is automatically determined by the LT8228
Short Protection
or externally controlled. The input and output protec- n
Switching MOSFET Short Detection and Protection
tion MOSFETs protect against negative voltages, control n
10V Gate Drive
inrush currents and provide isolation between terminals n Wide Input and Output Voltage Range Up to 100V under fault conditions such as switching MOSFET shorts. n Feedback Voltage Tolerance: ±1.0% Over Temperature In buck mode, the protection MOSFETs at the V1 termi- n Bidirectional Programmable Current Regulation and nal prevents reverse current. In boost mode, the same Monitoring MOSFETs regulate the output inrush current and protects n Extensive Self-Test, Diagnostics and Fault Reporting itself with an adjustable timer circuit breaker. n Programmable Fixed or Synchronizable Switching The LT8228 offers bidirectional input and output cur- Frequency: 80kHz to 600kHz rent limit as well as independent current monitoring. n Programmable Soft-Start and Dynamic Current Limit Masterless, fault tolerant current sharing allows any n Masterless, Fault Tolerant Current Sharing LT8228 in parallel to be added or subtracted while main- taining current sharing accuracy. Internal and external
APPLICATIONS
fault diagnostics and reporting are available via the FAULT n Dual Battery Automotive and Industrial Systems and REPORT pins. The LT8228 is available in a 38-lead n High Power System Backup and Supply Stabilization TSSOP package. n “N+1” Redundant, High Reliability Power Supplies All registered trademarks and trademarks are the property of their respective owners. n Power Interrupt Protection System
TYPICAL APPLICATION Simplified Bidirectional Battery Backup System Buck and Boost Mode Transitions
BOOST (48V AT 10A) 2mΩ V1 SUPPLY IL 24V TO 20A/DIV 54V BUCK (14V AT 40A) 10µH 2mΩ DRVCC V2 BATTERY 14V DRXN 2V/DIV SNS1P SNS1N TG BST SW BG SNS2P SNS2N 50µs/DIV 8228 TA01b V1D DS2 DS1 DG2 µC VDD DG1 LT8228 V1 BIAS FAULT IL V 20A/DIV 2 REPORT DRVCC DRXN µC I/O GND DRXN 2V/DIV 8228 TA01a 100µs/DIV 8228 TA1c Rev. 0 Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Buck Efficiency and Operation Typical Performance Characteristics Boost Efficiency and Operation ENABLE, Supply Current and VCC SS Current, Frequency, Thresholds and Driver Protection MOSFET Controller Pin Functions Block Diagram Operation Overview Buck Mode Operation Boost Mode Operation V1 Protection MOSFET Controller Operation V2 Protection MOSFET Controller Operation Mode of Operation (DRXN) Enable and Soft-Start (Enable and SS) Paralleling Multiple Controllers (ISHARE AND IGND) BIAS Supply and VCC Regulators Strong Gate Drivers Frequency Selection, Spread Spectrum and Phase-Locked Loop (RT and SYNC) FAULT Monitoring and REPORT Feature Applications Information Introduction Programming the Switching Frequency Inductor Selection RSNS2 and RIN2 Selection for Peak Inductor Current RSET2P Selection for V2 Output Current Limit (Buck Mode) RSET2N Selection for V2 Input Current Limit (Boost Mode) RMON2 Selection for V2 Current Monitoring RSNS1 and RIN1 Selection RSET1P Selection for V1 Input Current Limit (Buck Mode) RSET1N Selection for V1 Output Current Limit (Boost Mode) RMON1 Selection for V1 Current Monitoring Output Voltage, Input Undervoltage and Output Overvoltage Programming Power MOSFET Selection and Efficiency Considerations Optional Schottky Diode (D2 and D3) Selection Top MOSFET Driver Supply (CBST, DBST) Power Path Capacitor Selection Loop Compensation Inrush Current Control Boost Output Short Protection and Timer FAULT Conditions Soft-Start REPORT Feature Paralleling Multiple LT8228s BIAS, DRVCC, INTVCC and Power Dissipation Thermal Shutdown Pin Clearance/Creepage Consideration Efficiency Considerations PC Board Layout Checklist Design Example Package Description Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Typical Application Related Parts