LTC3350_15 Datasheet, PDF (1/46 Pages) Linear Technology – High Current Supercapacitor Backup Controller and System Monitor

LTC3350
Features
High Current Supercapacitor
Backup Controller and
System Monitor
Description
n _{High Efficiency Synchronous Step-Down CC/CV}
Charging of One to Four Series Supercapacitors
n _{Step-Up Mode in Backup Provides Greater}
Utilization of Stored Energy in Supercapacitors
n _{14-Bit ADC for Monitoring System Voltages/Currents,}
Capacitance and ESR
n _{Active Overvoltage Protection Shunts}
n _{Internal Active Balancers—No Balance Resistors}
n _{VIN: 4.5V to 35V, VCAP(n): Up to 5V per Capacitor,}
Charge/Backup Current: 10+A
n _{Programmable Input Current Limit Prioritizes System}
Load Over Capacitor Charge Current
n _{Dual Ideal Diode PowerPath™ Controller}
n _{All N-FET Charger Controller and PowerPath Controller}
n _{Compact 38-Lead 5mm × 7mm QFN Package}
Applications
n _{High Current 12V Ride-Through UPS}
n _{Servers/Mass Storage/High Availability Systems}
The LTC^®3350 is a backup power controller that can charge
and monitor a series stack of one to four supercapacitors.
The LTC3350’s synchronous step-down controller drives
N‑channel MOSFETs for constant current/constant voltage
charging with programmable input current limit. In addition,
the step-down converter can run in reverse as a step-up
converter to deliver power from the supercapacitor stack
to the backup supply rail. Internal balancers eliminate the
need for external balance resistors and each capacitor has
a shunt regulator for overvoltage protection.
The LTC3350 monitors system voltages, currents, stack
capacitance and stack ESR which can all be read over
the I²C/SMBus. The dual ideal diode controller uses
N-channel MOSFETs for low loss power paths from the
input and supercapacitors to the backup system supply.
The LTC3350 is available in a low profile 38-lead 5mm ×
7mm × 0.75mm QFN surface mount package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Patents pending.
Typical Application
High Current Supercapacitor Charger and Backup Supply
I_CHG (STEP-DOWN)
I_BACKUP
V_IN
V_OUT
INFET VOUTSP VOUTSN
PFI
OUTFB
Backup Operation
P_BACKUP = 25W
OUTFET
TGATE
SW
BGATE
LTC3350
ICAP
VCAP
I²C
CAP4
CAP3
CAP2
CAP1
CAPRTN
CAPFB
V_CAP < V_OUT
(STEP-UP)
V_CAP > V_OUT
(DIRECT
CONNECT)
V_CAP
10F
10F
10F
10F
3350 TA01a
V_OUT
2V/DIV
V_CAP
2V/DIV
V_IN
2V/DIV
V_IN
0V
400ms/DIV
BACK PAGE APPLICATION CIRCUIT
For more information www.linear.com/LTC3350
V_OUT
V_CAP
3350 TA01a
3350fb
1