LT3652 Datasheet, PDF (1/26 Pages) Linear Technology – Power Tracking 2A Battery Charger for Solar Power

LT3652
Power Tracking 2A Battery
Charger for Solar Power
FEATURES
n _{Input Supply Voltage Regulation Loop for Peak}
Power Tracking in (MPPT) Solar Applications
n _{Wide Input Voltage Range: 4.95V to 32V (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 14.4V}
Accommodates Li-Ion/Polymer, LiFePO₄, SLA,
NiMH/NiCd Chemistries
n _{No VIN Blocking Diode Required for Battery}
Voltages ≤ 4.2V
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}
n _{3mm × 3mm DFN12 or MSOP-12 Packages}
APPLICATIONS
n _{Solar Powered Applications}
n _{Remote Monitoring Stations}
n _{LiFePO4 (Lithium Phosphate) Applications}
n _{Portable Handheld Instruments}
n _{12V to 24V Automotive Systems}
DESCRIPTION
The LT^®3652 is a complete monolithic step-down bat-
tery charger that operates over a 4.95V to 32V input
voltage range. The LT3652 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 14.4V can be
programmed with a resistor divider.
The LT3652 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
LT3652 is powered by a solar panel, the input regulation
loop is used to maintain the panel at peak output power.
The LT3652 can be configured to terminate charging
when charge current falls below 1/10 of the programmed
maximum (C/10). Once charging is terminated, the LT3652
enters a low-current (85μA) standby mode. An auto-re-
charge feature starts a new charging cycle if the battery
voltage falls 2.5% below the programmed float voltage.
The LT3652 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 of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
2A Solar Panel Power Manager With 7.2V LiFePO₄ Battery
and 17V Peak Power Tracking
CMSH1-40MA
SOLAR PANEL INPUT
(<40V OC VOLTAGE)
10μF
CMSH3-40MA
SYSTEM LOAD
530k
100k
V_IN
SW
LT3652
V_{IN_REG}
BOOST
SHDN
SENSE
CHRG
BAT
FAULT
NTC
1μF
542k
10μH
0.05
CMSH3-40MA
10μF
TIMER
V_FB
459k
+
10k
B = 3380
2-CELL LiFePO₄ (2 × 3.6V) BATTERY PACK
3652 TA01a
Solar Panel Input Voltage
Regulation, Tracks Max Power
Point to Greater Than 98%
22
T_A = 25°C
20
18
100% TO 98% PEAK POWER
16
98% TO 95% PEAK POWER
14
12
10
0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
CHARGER OUTPUT CURRENT (A)
3652 TA01b
3652fb
1