LT3652HV_15 Datasheet, PDF (1/24 Pages) Linear Technology – Power Tracking 2A Battery Charger

LT3652HV
Power Tracking 2A Battery
Charger
FEATURES
n _{Input Supply Voltage Regulation Loop for Peak}
Power Tracking in (MPPT) Solar Applications
n _{Wide Input Voltage Range: 4.95V to 34V (40V Abs Max)}
n _{Programmable Charge Rate Up to 2A}
n _{User Selectable Termination: C/10 or On-Board}
Termination Timer
n _{Resistor Programmable Float Voltage Up to 18V}
Accommodates 4-Cell Li-Ion/Polymer, 5-Cell
LiFePO₄, Lead-Acid Chemistries
n _{Parallelable for Higher Output Current}
n _{1MHz Fixed Frequency}
n _{0.5% Float Voltage Reference Accuracy}
n _{5% Charge Current Accuracy}
n _{2.5% C/10 Detection Accuracy}
n _{Binary-Coded Open-Collector Status Pins}
APPLICATIONS
n _{Solar Powered Applications}
n _{Remote Monitoring Stations}
n _{Portable Handheld Instruments}
n _{12V to 24V Automotive Systems}
n _{Battery Charging from Current Limited Adapter}
DESCRIPTION
The LT^®3652HV is a complete monolithic step-down bat-
tery charger that operates over a 4.95V to 34V input range.
The LT3652HV provides a constant-current/constant-voltage
charge characteristic, with maximum charge current
externally programmable up to 2A. The charger employs
a 3.3V float voltage feedback reference, so any desired
battery float voltage up to 18V can be programmed with a
resistor divider.
The LT3652HV employs an input voltage regulation loop,
which reduces charge current if the input voltage falls below
a programmed level, set with a resistor divider. When the
LT3652HV is powered by a solar panel, the input regulation
loop is used to maintain the panel at peak output power.
The LT3652HV can be configured to terminate charging when
charge current falls below 1/10 of the programmed maximum
(C/10). Once charging is terminated, the LT3652HV enters a
low-current (85µA) standby mode. An auto-recharge feature
starts a new charging cycle if the battery voltage falls 2.5%
below the programmed float voltage. The LT3652HV also
contains a programmable safety timer, used to terminate
charging after a desired time is reached. This allows top-off
charging at currents less than C/10.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
V_{IN_REG} Loop Servos Maximum Charge Current to Prevent AC Adapter Output from
Drooping Lower Than 24V 5-Cell LiFePO₄ Charger (18V at 1.5A) with C/10 Termination
Powered by Inexpensive 24VDC/1A Unregulated Wall Adapter.
AC ADAPTER
INPUT
24VDC AT 1A
MBRS340
750k
10µF
44.2k
51.1k
V_IN
SW
LT3652HV
V_{IN_REG}
BOOST
SHDN
SENSE
CHRG
BAT
FAULT
NTC
TIMER
V_FB
3652 TA01a
1µF 10V 1N4148
D3
MBRS340
20µH
0.068
SYSTEM
LOAD
665k
127k
150k
R1
10K
B = 3380
+
10µF
5-CELL LiFePO₄ PACK
(18V FLOAT)
1A/24VDC Unregulated Adapter
I vs V Characteristic
36
33
30
27
24
21
18
15
12
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
ADAPTER OUTPUT CURRENT (A)
3652 TA01b
3652hvfa
1