LTC4079_15 Datasheet, PDF (1/20 Pages) Linear Technology – 60V, 250mA Linear Charger with Low Quiescent Current

LTC4079
60V, 250mA Linear Charger
with Low Quiescent Current
Features
n _{Wide Input Voltage Range: 2.7V to 60V}
n _{Adjustable Battery Voltage: 1.2V to 60V}
n _{Adjustable Charge Current: 10mA to 250mA}
n _{Low Quiescent Current While Charging: IIN = 4µA}
n _{Ultralow Battery Drain When Shutdown or Charged:}
I_BAT < 0.01µA
n _{Auto Recharge}
n _{Input Voltage Regulation for High Impedance Sources}
n _{Thermal Regulation Maximizes Output Current}
without Overheating
n _{Constant Voltage Feedback with ±0.5% Accuracy}
n _{NTC Thermistor Input for Temperature Qualified}
Charging
n _{Adjustable Safety Timer}
n _{Charging Status Indication}
n _{Thermally Enhanced 10-Lead (3mm × 3mm)}
DFN Package
Applications
n _{Embedded Automotive and Industrial}
n _{Backup Battery Charging from Another Battery}
n _{Energy Harvesting Charger}
n _{Thin Film Battery Products}
Description
The LTC^®4079 is a low quiescent current, high voltage
linear charger for most battery chemistry types including
Li-Ion/Polymer, Lead-Acid or NiMH battery stacks up to
60V. The maximum charge current is adjustable from
10mA to 250mA with an external resistor. The battery
charge voltage is set using an external resistor divider.
With an integrated power device, current sensing and
reverse current protection, a complete charging solution
using the LTC4079 requires very few external components.
Thermal regulation ensures maximum charge current up to
the specified limit without the risk of overheating. Charging
can be terminated by either C/10 or adjustable timer.
Input voltage regulation reduces charge current when
the input voltage falls to an adjustable level or the battery
voltage, making it well suited for energy harvesting
applications. Other features include temperature qualified
charging, bad battery detection, automatic recharge with
sampled feedback in standby for negligible battery drain,
and an open-drain CHRG status output. The device is
offered in a compact, thermally enhanced 10-lead (3mm
× 3mm) DFN package.
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
9V TO 60V
Charging a Backup Battery
IN
BAT
1µF
LTC4079
EN
FB
3.01k
CHRG
FBG
PROG NTCBIAS
TIMER NTC
GND
8.4V
1.54M
249k
10k
+
T 10k
Li-Ion
4079 TA01a
Li-Ion Battery Charge Cycle
140
8.6
500mAh 2-CELL LI-ION
120
V_BAT
8.4
100
I_BAT
8.2
80
8.0
60
7.8
40
C/10
TERMINATION
7.6
20
7.4
0
7.2
012345678
TIME (HOURS)
4079 TA01b
For more information www.linear.com/LTC4079
4079f
1