ISL78610 Datasheet, PDF (30/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
Figure 51 on page 31 shows the standard arrangement for
connecting the ISL78610 to a stack of 12 cells. The cell input
filter is designed to maximize EMI suppression. These
components should be placed close to the connector with a well
controlled ground to minimize noise for the measurement inputs.
The balance circuits shown in Figure 51 provide normal cell
monitoring when the balance circuit is turned off and a near zero
cell voltage reading when the balance circuit is turned on. This is
part of the diagnostic function of the ISL78610.
Figure 52 on page 32 shows connections for the daisy chain
system, setup pins, power supply and external voltage inputs for
daisy chain devices other than the master (stack bottom) device.
Figure 53 on page 33 shows the daisy chain system, setup pins,
microcontroller interface, power supply and external voltage
inputs for the daisy chain master device. Figure 53 is also
applicable to stand-alone (non-daisy chain) devices although in
this case, the daisy chain components connected to DHi2 and
DLo2 would be omitted.
Figure 54 on page 34 shows an alternate arrangement for the
battery connections in which the cell input circuits are connected
directly to the battery terminal and not via the balance resistor. In
this condition, the balance diagnostic function capability is
removed.
Operating with Reduced Cell Counts
When using the ISL78610 with fewer than 12 cells it is important
to ensure that each used cell has a normal input circuit
connection to the top and bottom monitoring inputs for that cell.
The simplest way to use the ISL78610 with any number of cells is
to always use the full input circuit arrangement for all inputs and
short together the unused inputs at the battery terminal. In this
way, each cell input sees a normal source impedance
independent of whether or not it is monitoring a cell.
The cell balancing components associated with unconnected cell
inputs are not required and can be removed. Unused cell balance
outputs should be tied to the adjacent cell voltage monitoring
pin.
The input circuit component count can be reduced in cases
where fewer than 10 cells are being monitored. It is important
that cell inputs that are being used are not connected to other
(unused) cell inputs as this would affect measurement accuracy.
Figures 55, through 57 starting on page 35, show examples of
systems with 10 cells, 8 cells, and 6 cells, respectively.
The component notations and values used in Figures 56 and 57
are the same as those used in Figures 51 to 54.
In Figure 57 the resistor associated with the input filter on VC9 is
noted as R₅, rather than R_5U. This value change is needed to
maintain the correct input network impedance in the absence of
the cell 9 balance circuits.
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FN8830.1
June 16, 2016