参数资料
型号: LTC4425IMSE#TRPBF
厂商: LINEAR TECHNOLOGY CORP
元件分类: 电源管理
英文描述: 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO12
封装: LEAD FREE, PLASTIC, MSOP-12
文件页数: 1/20页
文件大小: 239K
代理商: LTC4425IMSE#TRPBF
LTC4425
1
4425f
TYPICAL APPLICATION
FEATURES
DESCRIPTION
Linear SuperCap Charger
with Current-Limited Ideal
Diode and V/I Monitor
The LTC4425 is a constant-current/constant-voltage linear
charger designed to charge a 2-cell supercap stack from
either a Li-Ion/Polymer battery, a USB port, or a 2.7V to
5.5V current-limited supply. The part operates as an ideal
diode with an extremely low 50mΩ on-resistance making it
suitableforhighpeak-power/lowaveragepowerapplications.
The LTC4425 charges the output capacitors to an externally
programmed output voltage in LDO mode at a constant
charge current, or to VINinnormalmodewithasmartcharge
current prole to limit the inrush current until the VINtoVOUT
differential is less than 250mV. In addition the LTC4425 can
be set to clamp the output voltage to 4.9V or 5.4V.
Charge current (VOUT current limit) is programmed by
connecting a resistor between PROG and GND. The
voltage on the PROG pin represents the current owing
from VIN to VOUT for current monitoring. An internal active
balancing circuit maintains equal voltages across each
supercapacitor and clamps the peak voltage across each
cell to a pin-selectable maximum value. The LTC4425
operates at a very low 20μA quiescent current (shutdown
current <3μA) and is available in a low prole 12-pin
3mm
× 3mm DFN or a 12-lead MSOP package.
Charging 2-Cell Series Supercapacitor from Li-Ion Source
APPLICATIONS
n 50mΩ Ideal Diode from VIN to VOUT
n Smart Charge Current Prole Limits Inrush Current
n Internal Cell Balancer (No External Resistors)
n Programmable Output Voltage (LDO Mode)
n Programmable VIN to VOUT Current Limit
n Continuous Monitoring of VIN to VOUT Current via
PROG Pin
n Low Quiescent Current: 20μA
n VIN Power Fail, PGOOD Indicator
n 2.45V/2.7V Cell Protection Shunts
(4.9V/5.4V SuperCap Max Top-Off Voltage)
n 3A Peak Current Limit, Thermal Limiting
n Tiny Application Circuit, 3mm
× 3mm × 0.75mm DFN
and 12-Lead MSOP Packages
n High Peak Power Battery/USB Powered Equipment
n Industrial PDAs
n Portable Instruments/Monitoring Equipment
n Power Meters, SuperCap Backup Circuits
n PC Card/USB Modems
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
LTC4425
GND
+
Li-Ion
VIN
VOUT VIN
VIN
IMONITOR
1.5M
1.2M
2.2μF
PFI
PFI_RET
SEL
FROM
μC
EN
2.45V/2.7V
2k
PROG
PFO
470k
FB
1F
TO HIGH PEAK
POWER LOAD
VMID
4425 TA01
+
VIN – VOUT (V)
CHARGE
CURRENT
(A)
0.6
0.5
4425 TA02
0
0.1
0.2
0.3
0.4
0
0.2
0.4
0.6
0.8
1
1/10 CHARGE
CURRENT
CURRENT LIMITED
BY PMOS RDSON
IDEAL DIODE
FORWARD VOLTAGE = 15mV
FULL CHARGE CURRENT
VFB = VIN
RPROG = 2k
Charge Current vs VIN to VOUT Differential
相关PDF资料
PDF描述
LTC4425EMSE#PBF 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO12
LTC4425IDD#TRPBF 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO12
LTC6102IMS#TRPBF SPECIALTY ANALOG CIRCUIT, PDSO8
LTC6102HVIMS SPECIALTY ANALOG CIRCUIT, PDSO8
LTC6102CMS#TR SPECIALTY ANALOG CIRCUIT, PDSO8
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