LTC4020_15 Datasheet, PDF (1/42 Pages) Linear Technology – 55V Buck-Boost Multi-Chemistry Battery Charger

FEATURES
n _{Wide Voltage Range: 4.5V to 55V Input, Up to 55V}
Output (60V Absolute Maximums)
n _{Synchronous Buck-Boost DC/DC Controller}
n _{Li-Ion and Lead-Acid Charge Algorithms}
n _{±0.5% Float Voltage Accuracy}
n _{±5% Charge Current Accuracy}
n _{Instant-On for Heavily Discharged Batteries}
n _{Ideal Diode Controller Provides Low Loss}
PowerPath When Input Power is Limited
n _{Input Voltage Regulation for High Impedance Input}
Supplies and Solar Panel Peak Power Operation
n _{Onboard Timer for Protection and Termination}
n _{Bad Battery Detection with Auto-Reset}
n _{NTC Input for Temperature Qualified Charging}
n _{Binary Coded Open-Collector Status Pins}
n _{Low Profile (0.75mm) 38-Pin 5mm × 7mm QFN}
Package
APPLICATIONS
n _{Portable Industrial and Medical Equipment}
n _{Solar-Powered Systems}
n _{Military Communications Equipment}
n _{12V to 24V Embedded Automotive Systems}
LTC4020
55V Buck-Boost
Multi-Chemistry
Battery Charger
DESCRIPTION
The LTC^®4020 is a high voltage power manager provid-
ing PowerPath™ instant-on operation and high efficiency
battery charging over a wide voltage range. An onboard
buck-boost DC/DC controller operates with battery and/or
system voltages above, below, or equal to the input voltage.
The LTC4020 seamlessly manages power distribution
between battery and converter outputs in response to load
variations, battery charge requirements and input power
supply limitations.
The LTC4020 battery charger can provide a constant-current/
constant-voltage charge algorithm (CC/CV), constant-
current charging (CC), or charging with an optimized 4-step,
3-stage lead-acid battery charge profile. Maximum converter
and battery charge currents are resistor programmable.
The IC's instant-on operation ensures system load power
even with a fully discharged battery. Additional safety
features include preconditioning for heavily discharged
batteries and an integrated timer for termination and
protection.
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. Protected by U.S. Patents, including 7583113 and 8405362.
TYPICAL APPLICATION
Buck-Boost DC/DC Converter Controller with PowerPath Battery Charger Accepts
Inputs from 4.5V to 55V and Produces Output Voltages Up to 55V
R_SENSEA
V_IN
BUCK-BOOST
DC/DC CONVERTER
PowerPath BATTERY CHARGER
V_OUT
R_CS
R_SENSEB
LTC4020
R_NTC
5V to 30V 6-Cell Lead-Acid Supply/Charger
Maximum Power Efficiency vs V_IN
(Application Circuit on Page 37)
100
V_OUT = 14V
EFFICIENCY
95
90
INPUT POWER
85
80
P(LOSS)
75
5
10
15
20
V_IN (V)
100
90
80
70
60
50
40
30
20
10
0
25
30
4020 TA01b
4020 TA01a
For more information www.linear.com/LTC4020
4020fb
1