LTC3331_15 Datasheet, PDF (1/34 Pages) Linear Technology – Nanopower Buck-Boost DC/DC with Energy Harvesting Battery Charger

LTC3331
FEATURES
Nanopower Buck-Boost
DC/DC with Energy Harvesting
Battery Charger
DESCRIPTION
n _{Dual Input, Single Output DC/DCs with Input}
Prioritizer
Energy Harvesting Input: 3.0V to 19V Buck DC/DC
Battery Input: Up to 4.2V Buck-Boost DC/DC
n _{10mA Shunt Battery Charger with Programmable}
Float Voltages: 3.45V, 4.0V, 4.1V, 4.2V
n _{Low Battery Disconnect}
n _{Ultra Low Quiescent Current: 950nA at no Load}
n _{Integrated Supercapacitor Balancer}
n _{Up to 50mA of Output Current}
n _{Programmable DC/DC Output Voltage, Buck UVLO,}
and Buck-Boost Peak Input Current
n _{Integrated Low-Loss Full-Wave Bridge Rectifier}
n _{Input Protective Shunt: Up to 25mA at VIN ≥ 20V}
n _{5mm × 5mm QFN-32 Package}
APPLICATIONS
n _{Energy Harvesting}
n _{Solar Powered Systems with Battery Backup}
n _{Wireless HVAC Sensors and Security Devices}
n _{Mobile Asset Tracking}
The LTC^®3331 integrates a high voltage energy harvesting
power supply plus a buck-boost DC/DC powered from a
rechargeable battery to create a single output supply for
alternative energy applications. A 10mA shunt allows simple
charging of the battery with harvested energy while a low
battery disconnect function protects the battery from deep
discharge. The energy harvesting power supply, consisting
of an integrated full-wave bridge rectifier and a high voltage
buck DC/DC, harvests energy from piezoelectric, solar, or
magnetic sources. Either DC/DC converter can deliver en-
ergy to a single output. The buck operates when harvested
energy is available, reducing the quiescent current draw
on the battery to the 200nA required by the shunt charger,
thereby extending the life of the battery. The buck-boost
powers V_OUT only when harvested energy is unavailable.
A supercapacitor balancer is also integrated, allowing for
increased energy storage. Voltage and current settings
for both inputs and outputs are programmable via pin-
strapped logic inputs. The LTC3331 is available in a 5mm
× 5mm QFN-32 package.
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
+
SOLAR
PANEL
–
3V TO 19V
22µF
25V
AC1
V_IN
1µF
6.3V
AC2
SW
LTC3331
SWA
4.7µF, 6.3V
CAP
SWB
100k
4.7µF
6.3V
V_IN2
CHARGE
BB_IN
BAT_OUT
V_OUT
SCAP
BAL
+ ^Li-Ion
BATTERY
BAT_IN
EH_ON
4.7µF
6.3V
PGVOUT
2
FLOAT[1:0] OUT[2:0]
LBSEL
IPK[2:0]
SHIP
UV[3:0]
GND
V_IN3
22µH
22µH
10mF
2.7V
10mF
2.7V
3
OPTIONAL
3
4
0.1µF
6.3V
3331 TA01a
PIEZO
MIDE
V25W
1.8V TO 5V
50mA
47µF
6.3V
Charging a Battery with Harvested Energy
V_OUT
50mV/DIV
AC-COUPLED
EH_ON
4V/DIV
0V
I_{BB_IN}
200mA/DIV
0A
0A
I_CHARGE
1mA/DIV
BAT = 3.6V
V_OUT = 1.8V
I_LOAD = 50mA
ACTIVE ENERGY HARVESTER ENABLES
CHARGING OF THE BATTERY IN SLEEP
100µs/DIV
3331 TA01b
3331fb
For more information www.linear.com/LTC3331
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