LTC3305
Lead-Acid Battery Balancer
FEATURES DESCRIPTION
n
Single IC Balances Up to Four 12V Lead-Acid The LTC 3305 balances up to 4 lead-acid batteries
Batteries in Series connected in series. It is intended to be used in conjunction
n
All NFET Design with a separate pre-existing battery charger as part of a
n
Stackable to Balance Larger Series Battery Packs high performance battery system. All voltage monitoring,
n
Standalone Balancing Operation: Requires No gate drive, and fault detection circuitry is integrated.
External P or Additional Control Circuitry
The LTC3305 employs an auxiliary battery or an alternative
n
Balancing Current Limited by External PTC Thermistor
storage cell to transfer charge to or from each individual
n
Continuous Mode and Timer Mode
battery in the stack. A mode pin provides two operating
n
Programmable UV and OV Fault Thresholds
modes, timer mode and continuous mode. In timer mode,
n
Programmable Termination Time and Termination
once the balancing operation is completed, the LTC3305
Voltage
goes into a low power state for a programmed time and then
n
Thermally Enhanced 38-Lead TSSOP Package
periodically rebalances the batteries. In continuous mode,
the balancing operation continues even after the batteries
APPLICATIONS
are balanced to their programmed termination voltage.
n
Telecom Backup Systems
The LTC3305 is available in a thermally enhanced 38-lead
n
Home Battery Powered Backup Systems
TSSOP package.
n
Industrial Electric Vehicles
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
n
Energy Storage Systems (ESS)
Technology Corporation. All other trademarks are the property of their respective owners.
n
Medical Equipment
TYPICAL APPLICATION
4-Battery Balancer with Programmed High and Low Battery Voltage Faults
10F
25V
CHARGER
CM CP
V 1.33k
REG SUPPLY
249
EN1 NGATE5
EN2 6.04k I
BOOST CHARGE
BATTERY
Battery Voltages Converge
1F
MODE 10F
STACK
6V 25V
TERM1 CHARGER Over Time
V4
TERM2
NGATE4
+
10F 6.04k
16
BAT4
UVFLT
25V
OVFLT
14
DONE V3
NGATE3
100k EACH BAL +
12
BAT3
10F 3.01k
PTCFLT
25V
BATX
10
BATY
V2
CTON
LTC3305 NGATE2
+
10nF 10F 8
BAT2
6.04k
25V
CTOFF 6
100nF
V1
10F NGATE6 NGATE1
4
BATTERY 1
+
25V BAT1
CTBAT 6.04k
BATTERY 2
6.04k
10nF
2
BATTERY 3
9
BATTERY 4
NGATE1-9
NGATE7
V 0
L
6.04k
27.4k TIME
PTC
3305 TA01a
AUXP
+
V 10F
H
AUX
25V
42.2k
AUXN
6.04k
NGATE8
I
SET
GND
12.1k
3305 TA01
6.04k
NGATE9
3305fb
1
For more information www.linear.com/LTC3305
BATTERY VOLTAGE (V)LTC3305
ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION
(Note 1)
TOP VIEW
Stack Voltage, V4 to GND .........................................68V
BOOST 1 38 CM
Battery Voltages, V4 to V3, V3 to V2, V2 to V1,
V4 2 37 CP
V1 to GND .................................................. 0.3V to 20V
V3 3 36 NC
Auxiliary Cell Voltage, AUXP to AUXN ........ 0.3V to 20V
AUXP 4 35 MODE
V Voltage ................................................ 0.3V to 6V
REG
AUXN 5 34 EN1
V , V Voltage ..... 0.3V to Lesser of 6V or (V +0.3V)
H L REG
V2 6 33 EN2
UVFLT, OVFLT, PTCFLT, BAL, DONE, BATX,
V1 7 32 TERM1
BATY Voltage ............................................... 0.3V to 6V
NGATE1 8 31 TERM2
EN1, EN2, MODE, TERM1, TERM2
NGATE2 9 30 V
REG
Voltage ................ 0.3V to Lesser of 6V or (V +0.3V)
NGATE3 10 39 29 I
REG SET
GND
NGATE1, NGATE2, NGATE3, NGATE4, NGATE8, NGATE9 NGATE4 11 28 V
H
NGATE5 12 27 V
Voltage .............. 0.3V to Lesser of 68V or (V4+0.3V) L
NGATE6 13 26 CTBAT
NGATE5, NGATE6, NGATE7
NGATE7 14 25 CTON
Voltage .............. (Greater of 0.3V or BOOST68V) to
NGATE8 15 24 CTOFF
(BOOST+0.3V)*
NGATE9 16 23 PTCFLT
UVFLT, OVFLT, PTCFLT, BAL, DONE, BATX,
BATX 17 22 DONE
BATY Current .........................................................10mA
BATY 18 21 BAL
I Current ..............................................................1mA
SET
OVFLT 19 20 UVFLT
CP, CM Current.......................................................50mA
FE PACKAGE
Operating Junction Temperature Range
38-LEAD PLASTIC TSSOP
(Notes 2, 3) ............................................ 40C to 125C
= 28C/W
JA
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB
Storage Temperature Range .................. 65C to 150C
NC = No Connect
Lead Temperature (Soldering, 10 sec) ...................300C
*The BOOST voltage is generated by the LTC3305 and is typically 8.45V higher than V4.
ORDER INFORMATION
(