Maxim MAX745C-D, MAX745EAP Datasheet

MAX745
Switch-Mode Lithium-Ion
Battery-Charger
________________________________________________________________
Maxim Integrated Products
1
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General Description
The MAX745 provides all functions necessary for charging lithium-ion battery packs. It provides a regu­lated charging current of up to 4A without getting hot, and a regulated voltage with only ±0.75% total error at the battery terminals. It uses low-cost, 1% resistors to set the output voltage, and a low-cost N-channel MOS­FET as the power switch.
The MAX745 regulates the voltage set point and charg­ing current using two loops that work together to transi­tion smoothly between voltage and current regulation. The per-cell battery voltage regulation limit is set between 4.0V and 4.4V using standard 1% resistors, and then the number of cells is set from 1 to 4 by pin­strapping. Total output voltage error is less than ±0.75%.
For a similar device with an SMBus™ microcontroller interface and the ability to charge NiCd and NiMH cells, refer to the MAX1647 and MAX1648. For a low-cost lithium-ion charger using a linear-regulator control scheme, refer to the MAX846A.
____________________________Features
Charges 1 to 4 Lithium-Ion Battery Cells±0.75% Voltage-Regulation Accuracy
Using 1% Resistors
Provides up to 4A without Excessive Heating90% EfficientUses Low-Cost Set Resistors and
N-Channel Switch
Up to 24V Input Up to 18V Maximum Battery Voltage300kHz PWM Operation: Low-Noise,
Small Components
Stand-Alone Operation; No Microcontroller
Needed
___________________________________________________Typical Operating Circuit
19-1182; Rev 2; 12/98
PART
MAX745EAP -40°C to +85°C
TEMP. RANGE PIN-PACKAGE
20 SSOP
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
Ordering Information
Pin Configuration appears on last page.
________________________Applications
Lithium-Ion Battery Packs Desktop Cradle Chargers Cellular Phones Notebook Computers Hand-Held Instruments
MAX745C/D 0°C to +70°C Dice*
*
Dice are tested at TA= +25°C.
SMBus is a trademark of Intel Corp.
(UP TO 24V)
REF
DCIN
V
IN
BST
VL
DHI
DLO
LX
CS
BATT
CELL
COUNT
SELECT
SET PER
CELL VOLTAGE
WITH 1% RESISTORS
ON
OFF
VADJ
STATUS
SETI
CELL0 CELL1
CCI PGNDGND
IBAT
CCV
N
N
I
CHARGE
R
SENSE
VOUT 1–4 Li+ CELLS (UP TO 18V)
MAX745
THM/SHDN
MAX745
Switch-Mode Lithium-Ion Battery Charger
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DCIN
= 18V, V
BATT
= 8.4V, TA= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DCIN to GND............................................................-0.3V to 26V
BST, DHI to GND......................................................-0.3V to 30V
BST to LX....................................................................-0.3V to 6V
DHI to LX............................................(LX - 0.3V) to (BST + 0.3V)
LX to GND................................................-0.3V to (DCIN + 0.3V)
VL to GND...................................................................-0.3V to 6V
CELL0, CELL1, IBAT, STATUS, CCI, CCV, REF, SETI, VADJ, DLO, THM/
SHDN to GND ..-0.3V to (VL + 0.3V)
BATT, CS to GND .....................................................-0.3V to 20V
PGND to GND..........................................................-0.3V to 0.3V
VL Current...........................................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
SSOP (derate 8.00mW/°C above +70°C) ......................640mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature.........................................-60°C to +150°C
Lead Temperature (soldering, 10sec).............................+300°C
6.0V < V
DCIN
< 24V, logic inputs = VL
VL < 3.2V, VCS= 12V
VL < 3.2V, V
BATT
= 12V
Output high or low
0 < I
REF
< 1mA
6.0V < V
DCIN
< 24V, no load
TA= +25°C
Output high or low
CONDITIONS
V019BATT, CS Input Voltage Range
µA
5
CS Input Current
µA
5
BATT Input Current
614DLO On-Resistance
47DHI On-Resistance
mA46DCIN Quiescent Supply Current
V624DCIN Input Voltage Range
% 89 93DHI Maximum Duty Cycle
kHz270 300 330Oscillator Frequency
mV/mA10 20REF Output Load Regulation
V5.15 5.40 5.65VL Output Voltage V
4.17 4.2 4.23
REF Output Voltage
UNITSMIN TYP MAXPARAMETER
4V < V
BATT
< 16V
6.0V < V
DCIN
< 24V
mV±1.5CS to BATT Offset Voltage (Note 1)
SETI = V
REF
(full scale)
mV
170 185 205
CS to BATT Current-Sense Voltage
Not including VADJ resistor tolerance
%
-0.65 0.65
Absolute Voltage Accuracy
With 1% tolerance VADJ resistors
4.16 4.2 4.24
-0.75 0.75
SWITCHING REGULATOR
SUPPLY AND REFERENCE
VL > 5.15V, V
BATT
= 12V
VL > 5.15V, VCS= 12V 400
500
SETI = 400mV 14 18 22
MAX745
_______________________________________________________________________________________
3
Switch-Mode Lithium-Ion
Battery Charger
Note 1: When V
SETI
= 0V, the battery charger turns off.
ELECTRICAL CHARACTERISTICS (continued)
(V
DCIN
= 18V, V
BATT
= 8.4V, TA= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS
(V
DCIN
= 18V, V
BATT
= 8.4V, TA= -40°C to +85°C, unless otherwise noted. Limits over temperature are guaranteed by design.)
6.0V < V
DCIN
< 24V
6.0V < V
DCIN
< 24V, no load
Output high or low
Output high or low
CONDITIONS
mV165 205
CS to BATT Full-Scale Current-Sense Voltage
Not including VADJ resistors %-1.0 1.0Absolute Voltage Accuracy
V4.14 4.26REF Output Voltage
V5.10 5.70VL Output Voltage
14DLO On-Resistance
7DHI On-Resistance
kHz260 340Oscillator Frequency
UNITS
MIN TYP MAX
PARAMETER
IBAT Compliance Voltage Range 02V
V
IBAT
= 2V
IBAT Output Current vs. Current-Sense Voltage
0.9
µA/mV
Charger in voltage-regulation mode, V
STATUS
= 5V
STATUS Output Leakage Current 1
µA
Charger in current-regulation mode, STATUS sinking 1mA
STATUS Output Low Voltage 0.2 V
THM/SHDN Falling Threshold
2.01 2.1 2.19 V
THM/SHDN Rising Threshold
2.20 2.3 2.34 V
1.1V < V
CCI
< 3.5VCCV Clamp Voltage with Respect to CCI
PARAMETER MIN TYP MAX UNITS
GMV Amplifier Output Current ±130
µA
GMI Amplifier Transconductance 200
µA/V
GMI Amplifier Output Current ±320
µA
CCI Clamp Voltage with Respect to CCV 25 80 200 mV
25 80 200 mV
CELL0, CELL1 Input Bias Current -1 1
µA
SETI Input Voltage Range (Note 1) 0V
REF
V
SETI, VADJ Input Bias Current -10 10 nA
VADJ Adjustment Range 10 %
CONDITIONS
VADJ Input Voltage Range 0 V
REF
1.1V < V
CCV
< 3.5V
V
SWITCHING REGULATOR (Note 1)
SUPPLY AND REFERENCE
GMV Amplifier Transconductance 800
µA/V
CONTROL INPUTS/OUTPUTS
ERROR AMPLIFIERS
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