BQ29311_15 Datasheet, PDF (17/24 Pages) Texas Instruments – FOUR-CELL LITHIUM-ION

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Not Recommended for New Designs
bq29311
SLUS487D − DECEMBER 2001 − REVISED NOVEMBER 2003
SCD b7...b4 With Corresponding Delay Time
0000
0 µs
0100
244 µs
0001
61 µs
0101
305 µs
0010
122 µs
0110
366 µs
0011
183 µs
0111
427 µs
1000
1001
1010
1011
488 µs
549 µs
610 µs
671 µs
1100
1101
1110
1111
732 µs
793 µs
854 µs
915 µs
CELL_SELECT: CELL SELECTION
7
CELL4
6
CELL3
5
CELL2
CELL_SELECT REGISTER (0X06)
4
3
CELL1
CAL1
2
CAL0
1
VM1
0
VM0
This register determines cell selection for voltage measurement and translation, cell balancing and the operational mode
of the cell voltage monitoring.
CELL_SELECT b0−b1 (VM0−VM1)
These two bits select the series cell for voltage measurement translation.
VM1 VM0
SELECTED CELL
0
0 Bottom series element (default)
0
1 Second lowest series element
1
0 Second highest series element
1
1 Top series element
CELL_SELECT b2−b3 (CAL0, CAL1): These bits determine the mode of the voltage monitor block.
CAL1 CAL0
MEASUREMENT MODE
0
0 Cell translation for selected cell (default)
0
1 Offset measurement for selected cell
1
x
Monitor the VREF value for gain calibration
CELL_SELECT b3 −b6 (CELL1 −CELL4): These four bits select the series cell for cell balance discharge. Cell balance
discharge is disabled if bits b4...b7 are set to zero (default), and all cells are discharged if bits b4...b7 are set to 1.
CELL1 =1 = bottom series element
CELL2 =1 = second lowest series element
CELL3 =1 = second highest series element
CELL4 =1 = top series element
Figure 2 shows a typical application for the bq29311 smart lithium-ion battery protector. All functions required to protect
three- or four-series lithium-ion cells from overcharge and over-discharge, as well as provide short-circuit protection, are
included in a single chip.
An R-C filter is recommended at the VCELL pin where R_(VCELL) = 100 Ω (typ) and C_(VCELL) = 100 nF (typ)
CELL CONNECTION ORDER
The cells should be connected in the following order: Bat− to VC5, Bat+ to VC1, top of bottom cell to VC4, top of second
cell to VC3 and top of third cell to VC2.
3 OR 4 CELL CONFIGURATION
The 4-series cell configuration is shown in Figure 1. In a 3-cell configuration, VC1 is shorted to VC2, and R3 and C13 are
removed. VC2, VC3, VC4, and VC5 pins are used for three cells.
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