MAX1737_07 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – Stand-Alone Switch-Mode Lithium-Ion Battery-Charger Controller

19-1626; Rev 4; 9/07
EVAALVUAAILTAIOBNLEKIT
Stand-Alone Switch-Mode
Lithium-Ion Battery-Charger Controller
General Description
The MAX1737 is a switch-mode lithium-ion (Li+) battery
charger that charges one to four cells. It provides a
regulated charging current and a regulated voltage
with only a ±0.8% total voltage error at the battery ter-
minals. The external N-channel switch and synchronous
rectifier provide high efficiency over a wide input volt-
age range. A built-in safety timer automatically termi-
nates charging once the adjustable time limit has been
reached.
The MAX1737 regulates the voltage set point and charg-
ing current using two loops that work together to transi-
tion smoothly between voltage and current regulation. An
additional control loop monitors the total current drawn
from the input source to prevent overload of the input
supply, allowing the use of a low-cost wall adapter.
The per-cell battery voltage regulation limit is set
between +4.0V and +4.4V and can be set from one to
four by pin strapping. Battery temperature is monitored
by an external thermistor to prevent charging if the bat-
tery temperature is outside the acceptable range.
The MAX1737 is available in a space-saving 28-pin
QSOP package. Use the evaluation kit (MAX1737EVKIT)
to help reduce design time.
Applications
Notebook Computers
Hand-Held Instruments
Li+ Battery Packs
Desktop Cradle Chargers
Pin Configuration
TOP VIEW
VL 1
ISETIN 2
ISETOUT 3
THM 4
REF 5
GND 6
BATT 7
VADJ 8
CCV 9
CCS 10
CCI 11
CELL 12
TIMER1 13
TIMER2 14
MAX1737
28 DCIN
27 CSSP
26 CSSN
25 DHI
24 LX
23 BST
22 VLO
21 DLO
20 PGND
19 CS
18 SHDN
17 FULLCHG
16 FASTCHG
15 FAULT
QSOP
Features
♦ Stand-Alone Charger for Up to Four Li+ Cells
♦ ±0.8% Accurate Battery Regulation Voltage
♦ Low Dropout: 98% Duty Cycle
♦ Safely Precharges Near-Dead Cells
♦ Continuous Voltage and Temperature Monitoring
♦ <1µA Shutdown Battery Current
♦ Input Voltage Up to +28V
♦ Safety Timer Prevents Overcharging
♦ Input Current Limiting
♦ Space-Saving 28-Pin QSOP
♦ 300kHz PWM Oscillator Reduces Noise
♦ 90% Conversion Efficiency
PART
MAX1737EEI
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
28 QSOP
Typical Operating Circuit
INPUT SUPPLY
ON
OFF
DCIN CSSP
VL
CSSN
DHI
REF ^{MAX1737 LX}
ISETIN
BST
ISETOUT
VLO
CELL
DLO
VADJ
PGND
CS
CCS
BATT
CCV
CCI
TIMER1
TIMER2
THM
FASTCHG
FULLCHG
FAULT
SHDN
GND
SYSTEM
LOAD
RS
Li+
BATTERY
1 TO 4
CELLS
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.