LT8228 Controller Datasheet

LT8228 Datasheet, PDF, Equivalent


Part Number

LT8228

Description

Bidirectional Synchronous 100V Buck/Boost Controller

Manufacture

Analog Devices

Total Page 30 Pages
Datasheet
Download LT8228 Datasheet


LT8228
LT8228
Bidirectional Synchronous
100V Buck/Boost Controller with Reverse Supply,
Reverse Current and Fault Protection
FEATURES
n Bidirectional Voltage or Current Regulation
n Bidirectional Reverse Current Protection
n Input and Output Negative Voltage Protection to –60V
n Bidirectional Inrush Current Limit and Boost Output
Short Protection
n Switching MOSFET Short Detection and Protection
n 10V Gate Drive
n Wide Input and Output Voltage Range Up to 100V
n Feedback Voltage Tolerance: ±1.0% Over Temperature
n Bidirectional Programmable Current Regulation and
Monitoring
n Extensive Self-Test, Diagnostics and Fault Reporting
n Programmable Fixed or Synchronizable Switching
Frequency: 80kHz to 600kHz
n Programmable Soft-Start and Dynamic Current Limit
n Masterless, Fault Tolerant Current Sharing
APPLICATIONS
n Dual Battery Automotive and Industrial Systems
n High Power System Backup and Supply Stabilization
n “N+1” Redundant, High Reliability Power Supplies
n Power Interrupt Protection System
DESCRIPTION
The LT®8228 is a 100V bidirectional constant-current or
constant-voltage synchronous buck or boost controller
with independent compensation network. The direction of
the power flow is automatically determined by the LT8228
or externally controlled. The input and output protec-
tion MOSFETs protect against negative voltages, control
inrush currents and provide isolation between terminals
under fault conditions such as switching MOSFET shorts.
In buck mode, the protection MOSFETs at the V1 termi-
nal prevents reverse current. In boost mode, the same
MOSFETs regulate the output inrush current and protects
itself with an adjustable timer circuit breaker.
The LT8228 offers bidirectional input and output cur-
rent limit as well as independent current monitoring.
Masterless, fault tolerant current sharing allows any
LT8228 in parallel to be added or subtracted while main-
taining current sharing accuracy. Internal and external
fault diagnostics and reporting are available via the FAULT
and REPORT pins. The LT8228 is available in a 38-lead
TSSOP package.
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
V1
SUPPLY
24V TO
54V
Simplified Bidirectional Battery Backup System
BOOST (48V AT 10A)
2mΩ
DRVCC
10µH
2mΩ
Buck and Boost Mode Transitions
BUCK (14V AT 40A)
IL
20A/DIV
V2
BATTERY
14V
DRXN
2V/DIV
SNS1P SNS1N TG BST SW BG
V1D
DS1
DG1
V1 BIAS
V2
DRVCC
LT8228
GND
SNS2P SNS2N
DS2
DG2
µC VDD
FAULT
REPORT
DRXN
8228 TA01a
µC I/O
Document Feedback
For more information www.analog.com
50µs/DIV
8228 TA01b
IL
20A/DIV
DRXN
2V/DIV
100µs/DIV
8228 TA1c
Rev. 0
1

LT8228
LT8228
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.................... 9
Buck Efficiency and Operation................................... 9
Typical Performance Characteristics................... 11
Boost Efficiency and Operation................................ 11
ENABLE, Supply Current and VCC.................................... 13
SS Current, Frequency, Thresholds and Driver ....... 15
Protection MOSFET Controller................................. 15
Pin Functions............................................... 16
Block Diagram.............................................. 23
Operation................................................... 24
Overview.................................................................. 24
Buck Mode Operation.............................................. 24
Boost Mode Operation.............................................25
V1 Protection MOSFET Controller Operation ...........26
V2 Protection MOSFET Controller Operation ........... 28
Mode of Operation (DRXN)...................................... 28
Enable and Soft-Start (Enable and SS)....................29
Paralleling Multiple Controllers (ISHARE 
and IGND)................................................................30
BIAS Supply and VCC Regulators............................. 31
Strong Gate Drivers................................................. 32
Frequency Selection, Spread Spectrum and Phase-
Locked Loop (RT and SYNC)................................... 32
FAULT Monitoring and REPORT Feature................... 32
Applications Information................................. 33
Introduction............................................................. 33
Programming the Switching Frequency...................33
Inductor Selection...................................................34
RSNS2 and RIN2 Selection for Peak Inductor 
Current..................................................................... 35
RSET2P Selection for V2 Output Current
Limit (Buck Mode) ..................................................36
RSET2N Selection for V2 Input Current
Limit (Boost Mode) ................................................. 37
RMON2 Selection for V2 Current Monitoring.............38
RSNS1 and RIN1 Selection.........................................38
RSET1P Selection for V1 Input Current
Limit (Buck Mode) .................................................. 39
RSET1N Selection for V1 Output Current
Limit (Boost Mode) .................................................40
RMON1 Selection for V1 Current Monitoring............. 41
Output Voltage, Input Undervoltage and Output
Overvoltage Programming....................................... 41
Power MOSFET Selection and Efficiency
Considerations......................................................... 42
Optional Schottky Diode (D2 and D3) Selection......45
Top MOSFET Driver Supply (CBST, DBST).................46
Power Path Capacitor Selection...............................46
Loop Compensation.................................................48
Inrush Current Control............................................. 49
Boost Output Short Protection and Timer...............50
FAULT Conditions..................................................... 52
Soft-Start................................................................. 53
REPORT Feature.......................................................53
Paralleling Multiple LT8228s....................................56
BIAS, DRVCC, INTVCC and Power Dissipation.......... 57
Thermal Shutdown..................................................58
Pin Clearance/Creepage Consideration.................... 59
Efficiency Considerations........................................ 59
PC Board Layout Checklist...................................... 59
Design Example.......................................................60
Package Description...................................... 67
Typical Application........................................ 68
Related Parts............................................... 68
Rev. 0
2 For more information www.analog.com


Features LT8228 Bidirectional Synchronous 100V B uck/Boost Controller with Reverse Suppl y, Reverse Current and Fault Protection FEATURES n Bidirectional Voltage or Current Regulation n Bidirectional Rev erse Current Protection n Input and Ou tput Negative Voltage Protection to – 60V n Bidirectional Inrush Current Lim it and Boost Output Short Protection n Switching MOSFET Short Detection and P rotection n 10V Gate Drive n Wide Inp ut and Output Voltage Range Up to 100V n Feedback Voltage Tolerance: ±1.0% O ver Temperature n Bidirectional Progra mmable Current Regulation and Monitorin g n Extensive Self-Test, Diagnostics a nd Fault Reporting n Programmable Fixe d or Synchronizable Switching Frequency : 80kHz to 600kHz n Programmable Soft- Start and Dynamic Current Limit n Mast erless, Fault Tolerant Current Sharing APPLICATIONS n Dual Battery Automotive and Industrial Systems n High Power S ystem Backup and Supply Stabilization n “N+1” Redundant, High Reliability Power Supplies n Power Interr.
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