Datasheet

LTC3300-1
16
33001fb
For more information www.linear.com/LTC3300-1
OPERATION
charge from the highest voltage cell(s) in the stack to other
lower voltage cells in the stack (active balancing). This
can be very efficient (in terms of charge recovery) for the
case where only a few cells in the overall stack are high,
but will be very inefficient (and time consuming) for the
case where only a few cells in the overall stack are low. A
bidirectional active balancing approach, such as employed
by the LTC3300-1, is needed to achieve minimum balanc
-
ing time and maximum charge recovery for all common
cell capacity errors.
V
CC
I
CHARGE
I
SECONDARY
I
PRIMARY
V
PRIMARY
V
SECONDARY
V
TOP_OF_STACK
L
PRI
10µH
G1P
I1P
R
SNS_SEC
25mΩ
R
SNS_PRI
25mΩ
G1S
I1S
I
LOAD
(48V)
(4V)
T: 1
•
•
5µs
Single-Cell Discharge Cycle for Cell 1 Single-Cell Charge Cycle for Cell 1
I
PEAK_PRI
= 2A
(I1P = 50mV)
t
I
PRIMARY
5µs
2A
t
–I
PRIMARY
~417ns
2A
t
–I
SECONDARY
52V
52.05V
t
V
PRIMARY
4V
50mV
50mV
50mV
48V
4V
48V
52V
t
V
SECONDARY
~417ns
I
PEAK_SEC
= 2A
(I1S = 50mV)
t
I
SECONDARY
33001 F02
52V
51.95V
t
V
PRIMARY
4V
50mV
4V
48V
50mV
50mV
52V
48V
t
V
SECONDARY
CELL 1
+
CELL 2
+
CELL 12
+
CELL 13
+
CELL N
+
Figure 2. Synchronous Flyback Balancing Example with T = 1, S = 12
Synchronous Flyback Balancer
The balancing architecture implemented by the LTC3300-1
is bidirectional synchronous flyback. Each LTC3300-1
contains six independent synchronous flyback controllers
that are capable of directly charging or discharging an
individual cell. Balance current is scalable with external
components. Each balancer operates independently of
the others and provides a means for bidirectional charge
transfer between an individual cell and a larger group of
adjacent cells. Refer to Figure 2.