1
dc2151af
DEMO MANUAL DC2151A
Description
LTC3331EUH
Nanopower Buck-Boost DC/DC with
Energy Harvesting Battery Charger
L
, L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered
trademarks of Linear Technology Corporation. Adaptive Power, C-Load, DirectSense, Easy Drive,
FilterCAD, Hot Swap, LinearView, µModule, Micropower SwitcherCAD, Multimode Dimming, No
Latency Δ∑, No Latency Delta-Sigma, No RSENSE, Operational Filter, PanelProtect, PowerPath,
PowerSOT, SmartStart, SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO
are trademarks of Linear Technology Corporation. Other product names may be trademarks of
the companies that manufacture the products.
BoarD photo
Figure 1. DC2151A Demoboard
Demonstration Circuit DC2151A is a nanopower buck-
boost DC/DC with energy harvesting battery charger
featuring the
LTC
®
3331
. The LTC3331 integrates a high
voltage energy harvesting power supply plus a DC/DC
converter powered by a rechargeable cell battery to create
a single output supply for alternative energy applications.
The energy harvesting power supply, consisting of an
integrated low-loss full-wave bridge with a high voltage
buck converter, harvests energy from piezoelectric, solar
or magnetic sources. The rechargeable cell input powers a
buck-boost converter capable of operating down to 1.8V
at its input. Either DC/DC converter can deliver energy to
a single output. The buck operates when harvested energy
is available, reducing the quiescent current drawn on the
battery to essentially zero. The buck-boost takes over
when harvested energy goes away.
A 10mA shunt allows simple battery charging with harvest
energy while a low battery disconnect function protects the
battery from deep discharge. A supercapacitor balancer
is also integrated, allowing for increased output storage.
Voltage and current settings for input and output as well
as the battery float voltage are programmable via pin-
strapped logic inputs.
The LTC3331EUH is available in a 5mm × 5mm 32-lead
QFN surface mount package with exposed pad.
Buck Efficiency vs I
LOAD
I
LOAD
(A)
EFFICIENCY (%)
3331 G34
100
90
60
80
70
40
50
20
10
30
0
1µ
10µ
10m
100m
1m
100µ
V
OUT
= 1.8V
V
OUT
= 2.5V
V
OUT
= 3.3V
V
OUT
= 5V
V
IN
= 6V, L = 22µH, DCR = 0.19Ω
Figure 2. Typical Efficiency of DC2151A
