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operating principle
Operation of the LTC6803-2 is detailed in the LTC6803-2
data sheet and the operation of the DC2064A GUI is similar
to the DC1652A GUI except additional functionality was
added to control the LTC3300-1 balancing devices. Refer
to the Quick Start Guide for the DC1652B for operation
of the LTC6803-2 GUI. The DC2064A has a two window
GUI, one window based on the DC1652A GUI to control
the LTC6803-2 with a tab to control the LTC3300-1 for
battery balancing and the second window to display the
status of the LTC3300-1 based on the command and status
registers read from the LTC3300-1.
The LTC3300-1 active balancer is a power stage control
IC. The LTC3300-1 does not have a balancer algorithm
built into it. The determination of the balancing times and
directions are performed at a system level and conveyed to
the LTC3300-1 through its SPI interface. The LTC3300-1
only accepts battery charge or discharge commands.
Quick start proceDure
The demonstration circuit is set up per Figure 29 to evaluate
the performance of the DC2064A bidirectional cell balancer
using the LTC3300-1.
Caution: BOT6_TS and TOP6_TS turrets must not be al-
lowed to float and must be connected to their respective
top of stack-battery terminal.
Using short twisted-pair leads for any power connec-
tions, refer to Figure 29 for the proper measurement and
equipment setup. The DC2064A will support a system of
4 to 12 batteries.
Recommended Cell Connection Sequence
The recommended cell connection sequence is to connect
–
the V
connection first followed by connecting cells 1
through cell 12. Disconnection of the cells should follow
this sequence in the reverse order with the V
being removed last. Connecting the V
removing last is recommended because the V
is the ground reference for the circuitry within the demo
board. After connecting the V
sequence is less critical as long as the cell circuit
capacitances are matched as they are in the demo board.
–
connection
–
connection first and
–
connection
–
, all other cell connection
DEMO MANUAL DC2064A
Charge is transferred to/from a cell (battery) from/to the
stack, a series connection of adjacent cells, through a
flyback converter that is operating in boundary mode.
During discharge of a cell, the current in the primary of
a coupled inductor transformer with a turns ratio of 1:2,
ramps up to 6.25A at which point the primary switch turns
off. The charge in the primary inductor is transferred to
the secondary inductor which is connected across the
12-cell pack. This pack current then passes through the
series connected cells thus distributing the charge equally
across each cell. When charging a cell, the current, in the
secondary of the coupled inductor transformer, ramps up
to 3.125A at which point the secondary switch turns off.
The charge in the secondary inductor is transferred to the
primary inductor which is connected across the cell. The
secondary current is drawn from the series connected
cells thus removing charge equally across each cell. The
efficiency through the flyback converter is ≈92%.
Following the recommended cell connection removes the
possibility of excessive voltage on any of the lower cells
due to an imbalance in cell circuit capacitance.
Follow the procedure outlined in the DC1835A Quick
Start Guide for general use of the modified LTC6803-2
GUI window. The 4-bit board ID code that is set by the
A0 through A3 jumpers on the DC2064A must match the
board Address box in the LTC6803-2 GUI window shown
in Figure 2 for each board in the system.
Figure 2. Board Address Box
dc2064afa
3
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