MAX712_02 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – NiCd/NiMH Battery Fast-Charge Controllers

19-0100; Rev 5; 4/02
EVAALVUAAILTAIOBNLEKIT
NiCd/NiMH Battery
Fast-Charge Controllers
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 5µA from the battery when not
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.
________________________Applications
Battery-Powered Equipment
Laptop, Notebook, and Palmtop Computers
Handy-Terminals
Cellular Phones
Portable Consumer Products
Portable Stereos
Cordless Phones
Pin Configuration
TOP VIEW
VLIMIT 1
BATT+ 2
PGM0 3
PGM1 4
THI 5
TLO 6
TEMP 7
FASTCHG 8
MAX712
MAX713
16 REF
15 V+
14 DRV
13 GND
12 BATT-
11 CC
10 PGM3
9 PGM2
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
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX712CPE
0°C to +70°C
16 Plastic DIP
MAX712CSE
0°C to +70°C
16 Narrow SO
MAX712C/D
0°C to +70°C
Dice*
MAX712EPE
-40°C to +85°C
16 Plastic DIP
MAX712ESE
-40°C to +85°C
16 Narrow SO
MAX712MJE
-55°C to +125°C 16 CERDIP**
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
Q1
2N6109
C4
R1 0.01µF
R2
150Ω
WALL
CUBE
10µF
C1
1µF
R3
68kΩ
R4
22kΩ
THI
DRV
V+
D1
1N4001
VLIMIT
REF
BATT+
MAX712
MAX713
TEMP
BATTERY
CC BATT- TLO GND
C3
10µF
LOAD
C2
0.01µF
R_SENSE
DIP/SO
SEE FIGURE 19 FOR SWITCH-MODE CHARGER CIRCUIT.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.