MAX846AEEE Maxim Integrated Products, MAX846AEEE Datasheet - Page 9

• Manufacturer Part Number: MAX846AEEE
• Description: Battery Management Multichemistry Bat Charger System
• Manufacturer: Maxim Integrated Products

Specifications of MAX846AEEE

• Battery Type: Li-Ion, Li-Polymer, NiCd, NiMH
• Output Voltage: 3.3 V
• Operating Supply Voltage: 3.7 V to 20 V
• Supply Current: 5 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Package / Case: QSOP-16
• Mounting Style: SMD/SMT

The current-regulation loop attempts to maintain the
voltage on ISET at 1.65V. Selecting resistor R
mines the reflected voltage required at the current-
sense amplifier input.
Figure 2. Stand-Alone Li-Ion Charger
where VX is either GND or VL, and V
float voltage. In the circuit of Figure 1, R
400kΩ. R
divider, resulting in an adjustment range of approxi-
mately ±5%.
DCIN
3.7V TO 20V
VSET
R
VSET
4.7 F
and the internal 20kΩ resistor form a
_______________________________________________________________________________________
100k
= 20k
0.01 F
0.01 F
CCI
CCV
OFFV
ON
DCIN
VL
PWROK
1.65
4.2
CS+
V
F
V
(
X
R
4.2
0.165V
CS
I
BATT
GND
F
CS-
V
is the per-cell
)
10nF
F
ISET
MAX846A
VSET
660
R
CAN BE EITHER PNP OR PMOS FET.
Cost-Saving Multichemistry
DRV
deter-
EXTERNAL PASS TRANSISTOR
is
Battery-Charger System
DRV
PGND
• Calculate R
• Connect ON to PWROK to prevent the charge current
Minimize power dissipation in the external pass transis-
tor. Power dissipation can be controlled by setting the
DCIN input supply as low as possible, or by making
V
The MAX846A is highly adjustable, allowing for simple
interfacing with a low-cost µC to charge Ni-based and
Li-Ion batteries using one application circuit (Figure 3).
DCIN
R
R
where the recommended value for V
from turning on until the voltages have settled.
CS
ISET
track the battery voltage.
= V
BATT
CELL2
(in kΩ) = 1.65V / V
VSET
ISET
CS
/ I
CS
4.7 F
BATT
and R
R
R
10k
VSET
ISET
Microprocessor-Controlled
Multichemistry Operation
ISET
VL
VL
CS
ADJUST
(DOWN)
(2 CELLS)
(1 CELL)
as follows:
(UP)
CS
is 165mV.
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