LT8708-1
1
Rev 0
LT8708*
CSPOUT
CSNOUT
EXTV
CC
VOUTLOMON
FBOUT
INTV
CC
GATEV
CC
IMON_OP
IMON_ON
IMON_INP
IMON_INN
CLKOUT
SS
RT
V
C
MODE
CSNIN
TG1 BOOST1 SW1 BG1 CSP CSN
LT8708-1
SLAVE
GND BG2 SW2 BOOST2 TG2
CSPIN
V
INCHIP
SHDN
VINHIMON
SWEN
SYNC
RVSOFF
ICP
ICN
SWEN
RVSOFF
ICP
ICN
DIR
CLKOUT
FWD (3V)
RVS (0V)
FBIN
DIR
10V TO 16V
BATTERY
TO DIODE
DB1
LD033
87081 TA01a
TO DIODE
DB2
V
BAT1
10V TO
16V
BATTERY
V
BAT2
LD033
DB1
DB2
TO
BOOST1
TO
BOOST2
LD033
LD033
120kHz
MASTER
POWER TRANSFER
DECISION LOGIC
*REFER TO
LT8708 DATA
SHEET FOR
MASTER SETUP
TYPICAL APPLICATION
FEATURES
DESCRIPTION
80V Synchronous 4-Switch Buck-Boost DC/DC
Slave Controller for LT8708 Multiphase System
The
is a high performance buck-boost
switching regulator controller that is paralleled with the
LT8708 to add power and phases to an LT8708 system.
The LT8708-1 always operates as a slave to the master
LT8708 and has the capability of delivering as much cur-
rent or power as the master. One or more slaves can be
connected to a single master, proportionally increasing
power and current capability of the system.
The LT8708-1 has the same conduction modes as LT8708,
allowing the LT8708-1 to conduct current and power in
the same direction(s) as the master. The master controls
the overall current and voltage limits for an LT8708 mul-
tiphase system, and the slaves comply with these limits.
LT8708-1s can be easily paralleled with the LT8708 by
connecting four signals together. Two additional current
limits (forward V
IN
current and reverse V
IN
current) are
available on each slave that can be set independently.
APPLICATIONS
n
Slave Chip of LT8708 to Deliver Additional Power
n
Good Current Matching to the Average Output
Current of LT8708 Through Current Regulation
n
Easily Paralleled with LT8708 Through Four Pins
n
Synchronized Start-Up with LT8708
n
Same Conduction Modes as LT8708
n
Synchronous Rectification: Up to 98% Efficiency
n
Frequency Range: 100kHz to 400kHz
n
Available in 40-Lead (5mm × 8mm) QFN with High
Voltage Pin Spacing
n
High Voltage Buck-Boost Converters
n
Bidirectional Charging Systems
n
Automotive 48V Systems
All registered trademarks and trademarks are the property of their respective owners.
The LT8708-1 Two-Phase 12V Bidirectional Dual Battery System with FHCM and RHCM
Efficiency
V
BAT2
= 13.5V
V
BAT2
CHARGING CURRENT = 30A
V
BAT1
(V)
10
12
14
16
94
95
96
97
98
99
100
EFFICIENCY (%)
Efficiency
87081 TA01b
