19-0100; Rev 3; 1/97
UALS
IT MAN
TION K
T
A
A SHEE
EVALU
W DAT
FOLLO
NiCd/NiMH Battery
Fast-Charge Controllers
____________________________Features
o
Fast Charge NiMH or NiCd Batteries
o
Voltage Slope, Temperature, and Timer
Fast-Charge Cutoff
o
Charge 1 to 16 Series Cells
o
Supply Battery’s Load while Charging (Linear Mode)
o
Fast Charge from C/4 to 4C Rate
o
C/16 Trickle-Charge Rate
o
Automatically Switch from Fast to Trickle Charge
o
Linear or Switch-Mode Power Control
o
5µA Max Drain on Battery when Not Charging
o
5V Shunt Regulator Powers External Logic
_______________General Description
The MAX712/MAX713 fast charge Nickel Metal Hydride
(NiMH) and Nickel Cadmium (NiCd) batteries from a DC
source at least 1.5V higher than the maximum battery
voltage. 1 to 16 series cells can be charged at rates up
to 4C. A voltage-slope detecting analog-to-digital convert-
er, timer, and temperature window comparator determine
charge completion. The MAX712/MAX713 are powered
by the DC source via an on-board +5V shunt regulator.
They draw a maximum of 5µ from the battery when not
A
charging. A low-side current-sense resistor allows the
battery charge current to be regulated while still
supplying power to the battery’s load.
The MAX712 terminates fast charge by detecting zero
voltage slope, while the MAX713 uses a negative
voltage-slope detection scheme. Both parts come in 16-
pin DIP and SO packages. An external power PNP tran-
sistor, blocking diode, three resistors, and three
capacitors are the only required external components.
For high-power charging requirements, the MAX712/
MAX713 can be configured as a switch-mode battery
charger that minimizes power dissipation. Two evaluation
kits are available: Order the MAX712EVKIT-DIP for quick
evaluation of the linear charger, and the MAX713EVKIT-
SO to evaluate the switch-mode charger.
MAX712/MAX713
______________Ordering Information
PART
MAX712CPE
MAX712CSE
MAX712C/D
MAX712EPE
MAX712ESE
MAX712MJE
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
PIN-PACKAGE
16 Plastic DIP
16 Narrow SO
Dice*
16 Plastic DIP
16 Narrow SO
16 CERDIP**
________________________Applications
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
Cellular Phones
Portable Consumer Products
Portable Stereos
Cordless Phones
Ordering Information continued at end of data sheet.
*Contact
factory for dice specifications.
**Contact
factory for availability and processing to MIL-STD-883.
__________Typical Operating Circuit
DC IN
C4
0.01µF
Q1
2N6109
R2
150Ω
R1
__________________Pin Configuration
TOP VIEW
VLIMIT 1
BATT+ 2
PGM0 3
PGM1 4
THI 5
TLO 6
TEMP 7
FASTCHG 8
16 REF
15 V+
14 DRV
WALL
CUBE
C1
1µF
R3
68kΩ
THI
V+
VLIMIT
REF
DRV
D1
1N4001
BATT+
C3
10µF
MAX712
MAX713
TEMP
BATTERY
MAX712
MAX713
13 GND
12 BATT-
11 CC
10 PGM3
9
PGM2
10µF
R4
22kΩ
LOAD
CC BATT- TLO GND
C2
0.01µF
R
SENSE
DIP/SO
SEE FIGURE 19 FOR SWITCH-MODE CHARGER CIRCUIT.
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
