|
|
PDF MAX745 Data sheet ( Hoja de datos )
| Número de pieza | MAX745 | |
| Descripción | Switch-Mode Lithium-Ion Battery-Charger | |
| Fabricantes | Maxim Integrated | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MAX745 (archivo pdf) en la parte inferior de esta página. Total 8 Páginas | ||
|
No Preview Available !
19-1182; Rev 2; 12/98
EVFAOLLULAOTWIOSNDKAITTAMSAHNEUEATL
Switch-Mode Lithium-Ion
Battery-Charger
General Description ____________________________Features
The MAX745 provides all functions necessary for
charging lithium-ion battery packs. It provides a regu-
lated 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 MOS-
FET as the power switch.
The MAX745 regulates the voltage set point and charg-
ing current using two loops that work together to transi-
tion 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 pin-
strapping. 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.
o Charges 1 to 4 Lithium-Ion Battery Cells
o ±0.75% Voltage-Regulation Accuracy
Using 1% Resistors
o Provides up to 4A without Excessive Heating
o 90% Efficient
o Uses Low-Cost Set Resistors and
N-Channel Switch
o Up to 24V Input
o Up to 18V Maximum Battery Voltage
o 300kHz PWM Operation: Low-Noise,
Small Components
o Stand-Alone Operation; No Microcontroller
Needed
________________________Applications
Lithium-Ion Battery Packs
Desktop Cradle Chargers
PART
MAX745C/D
Ordering Information
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
Dice*
Cellular Phones
Notebook Computers
Hand-Held Instruments
MAX745EAP
-40°C to +85°C 20 SSOP
Pin Configuration appears on last page.
*Dice are tested at TA = +25°C.
___________________________________________________Typical Operating Circuit
VIN
(UP TO 24V)
CELL
COUNT
SELECT
ON
OFF
SET PER
CELL VOLTAGE
WITH 1% RESISTORS
DCIN VL
CELL0
CELL1
MAX745
THM/SHDN
REF
SETI
VADJ
BST
DHI
LX
DLO
CS
STATUS
BATT
CCV CCI GND IBAT PGND
N
N
ICHARGE
RSENSE
VOUT
1–4 Li+ CELLS
(UP TO 18V)
SMBus is a trademark of Intel Corp.
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
1 page  
Switch-Mode Lithium-Ion
Battery Charger
______________________________________________________________Pin Description
PIN
1
2
3
4
5
6
7
8
9
10
11, 12
13
14
15
16
17
18
19
20
NAME
IBAT
DCIN
VL
CCV
CCI
THM/
SHDN
REF
VADJ
SETI
GND
CELL1,
CELL0
STATUS
BATT
CS
PGND
DLO
DHI
LX
BST
FUNCTION
Current-Sense Amplifier’s Analog Current-Source Output. See Monitoring Charge Current section for
detailed description.
Charger Input Voltage. Bypass DCIN with a 0.1µF capacitor.
Chip Power Supply. Output of the 5.4V linear regulator from DCIN. Bypass VL with a 4.7µF capacitor.
Voltage-Regulation-Loop Compensation Point
Current-Regulation-Loop Compensation Point
Thermistor Sense-Voltage Input. THM/SHDN also performs the shutdown function. If pulled low,
the charger turns off.
4.2V Reference Voltage Output. Bypass REF with a 0.1µF or greater capacitor.
Voltage-Adjustment Pin. VADJ is tied to a 1% tolerance external resistor-divider to adjust the voltage set
point by 10%, eliminating the need for precision 0.1% resistors. The input voltage range is 0V to VREF.
SETI is externally tied to the resistor-divider between REF and GND to set the charging current.
Analog Ground
Logic Inputs to Select Cell Count. See Table 1 for cell-count programming.
An open-drain MOSFET sinks current when in current-regulation mode, and is high impedance when in volt-
age-regulation mode. Connect STATUS to VL through a 1kΩ to 100kΩ pull-up resistor. STATUS may also drive
an LED for visual indication of regulation mode (see MAX745 evaluation kit). Leave STATUS floating if not used.
Battery-Voltage-Sense Input and Current-Sense Negative Input
Current-Sense Positive Input
Power Ground
Low-Side Power MOSFET Driver Output
High-Side Power MOSFET Driver Output
Power Connection for the High-Side Power MOSFET Source
Power Input for the High-Side Power MOSFET Driver
_______________Detailed Description
The MAX745 is a switch-mode, lithium-ion battery
charger that can achieve 90% efficiency. The charge
voltage and current are set independently by external
resistor-dividers at SETI and VADJ, and at pin connec-
tions at CELL0 and CELL1. VADJ is connected to a
resistor-divider to set the charging voltage. The output
voltage-adjustment range is ±5%, eliminating the need
for 0.1% resistors while still achieving 0.75% set accu-
racy using 1% resistors.
The MAX745 consists of a current-mode, pulse-width-
modulated (PWM) controller and two transconductance
error amplifiers: one for regulating current (GMI) and
the other for regulating voltage (GMV) (Figure 2). The
error amplifiers are controlled via the SETI and VADJ
pins. Whether the MAX745 is controlling voltage or cur-
rent at any time depends on the battery state. If the bat-
tery is discharged, the MAX745 output reaches the
current-regulation limit before the voltage limit, causing
the system to regulate current. As the battery charges,
the voltage rises to the point where the voltage limit is
reached and the charger switches to regulating volt-
age. The STATUS pin indicates whether the charger is
regulating current or voltage.
Voltage Control
To set the voltage limit on the battery, tie a resistor-
divider to VADJ from REF. A 0V to VREF change at
VADJ sets a ±5% change in the battery limit voltage
around 4.2V. Since the 0 to 4.2V range on VADJ results
in only a 10% change on the voltage limit, the resistor-
divider’s accuracy does not need to be as high as the
output voltage accuracy. Using 1% resistors for the
voltage dividers typically results in no more than 0.1%
degradation in output voltage accuracy. VADJ is inter-
nally buffered so that high-value resistors can be used
to set the output voltage. When the voltage at VADJ is
_______________________________________________________________________________________ 5
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet MAX745.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MAX7400 | 8th-Order / Lowpass / Elliptic / Switched-Capacitor Filters | Maxim Integrated |
| MAX7401 | 8th-Order / Lowpass / Bessel / Switched-Capacitor Filters | Maxim Integrated |
| MAX7403 | 8th-Order / Lowpass / Elliptic / Switched-Capacitor Filters | Maxim Integrated |
| MAX7404 | 8th-Order / Lowpass / Elliptic / Switched-Capacitor Filters | Maxim Integrated |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |