MAX1906VEEE Maxim Integrated, MAX1906VEEE Datasheet - Page 5

• Manufacturer Part Number: MAX1906VEEE
• Description: Battery Management
• Manufacturer: Maxim Integrated
• Series: MAX1906r

The MAX1906 protects 2-, 3-, or 4-series Li+ battery
packs from overcharge by controlling a three-terminal
protection fuse. Figures 1 and 2 show two application
circuits using the MAX1906. The MAX1906 checks the
voltage of each cell at regular intervals. An overcharge
condition is detected if any cell voltage exceeds the
overvoltage threshold for more than 2.1s. The MAX1906
responds to an overcharge condition by turning on an
internal SCR (Figure 1) or an external MOSFET (Figure 2)
to blow a three-terminal protection fuse placed in series
with the charging path.
The MAX1906 checks for disconnected voltage sense
pins every time it exits the standby mode or test mode. If
a disconnected pin is detected, the DISCON pin is
latched low. The MAX1906 also includes a test mode,
which determines if the circuit is operating correctly while
in an assembled battery pack. A pulse on the TEST pin
6, 11, 13, 15 6, 11, 13, 15 6, 11, 13, 15
MAX1906S
1, 9
10
12
—
—
2
3
4
5
7
8
MAX1906V
PIN
1, 9
10
12
14
—
2
3
4
5
7
8
_______________________________________________________________________________________
Detailed Description
MAX1906X
1, 9
10
12
14
16
2
3
4
5
7
8
Li+ Battery-Pack Protector with
DISCON
NAME
TEST
OUT
N.C.
DRV
PKN
B1P
B2P
B3P
B4P
I.C.
BN
Internal Connection. Float pins 1 and 9.
No Connection
MOSFET Driver Output. High when an overvoltage condition is detected.
Connect the DRV pin to the gate of an external MOSFET to blow the
protection fuse.
Test-Mode Input. Test mode is enabled with a pulse of minimum 50µs
duration on the TEST pin.
Disconnected Pin Output. This is an open-drain output and is high-Z during
normal operation. If B4P, B3P, B2P, or B1P is disconnected, this pin is
pulled low (see the Disconnected Pin Detection section).
Pack Negative. A sense resistor may be connected between BN and PKN.
Anode Output of the SCR. Connect OUT to the fuse’s heater connection (see
the Protection Fuse Selection section).
Negative Terminal of Cell 1. Connect BN to the negative terminal of the first
series Li+ cell. BN is also chip ground, which is connected to the backside
paddle on the QFN package.
Positive Terminal of Cell 1. Connect B1P to the positive terminal of the first
series Li+ cell.
Positive Terminal of Cell 2. Connect B2P to the positive terminal of the
second series Li+ cell.
Positive Terminal of Cell 3. Connect B3P to the positive terminal of the third
series Li+ cell.
Positive Terminal of Cell 4. Connect B4P to the positive terminal of the fourth
series Li+ cell.
enables the test mode. Figure 3 shows the cell connec-
tions for 2- and 3-series battery packs and Figure 4
shows the functional diagram for the MAX1906.
The MAX1906 can be used together with other
resettable protection circuits to provide a high level of
safety against overcharging Li+ batteries. Figure 5 shows
a typical application circuit using the MAX1906 together
with the MAX1924. The MAX1924 has a lower overvoltage
threshold than the MAX1906. If any cell voltage exceeds
4.35V (typ), the MAX1924 turns off the TKO and CGO
MOSFETs and opens the charging path. If the TKO or
CGO MOSFET fails and charging continues, the
MAX1906 blows the protection fuse and opens the charg-
ing path permanently once any cell voltage reaches
4.45V (typ). The MAX1924 also protects the battery pack
against undervoltage, charge current, discharge current,
and pack-short fault conditions. Refer to the MAX1894/
MAX1924 data sheets for complete details.
Integrated Fuse Driver
DESCRIPTION
Pin Description
5