Datasheet

LTC3108-1
13
31081fb
For more information www.linear.com/LTC3108-1
this manner, a Peltier cell is referred to as a thermoelectric
generator (TEG).
The low voltage capability of the LTC3108-1 design allows
it to operate from a TEG with temperature differentials
as low as 1°C, making it ideal for harvesting energy in
applications in which a temperature difference exists
between two surfaces or between a surface and the am
-
bient temperature. The internal resistance (ESR) of most
cells is in the range of 1Ω to 5Ω, allowing for reasonable
power transfer. The curves in Figure 2 show the open-
circuit output voltage and maximum power transfer for a
typical Peltier cell (with an ESR of 2Ω) over a 20°C range
of temperature differential.
TEG Load Matching
The LTC3108-1 was designed to present a minimum input
resistance (load) in the range of 2Ω to 10Ω, depending
on input voltage and transformer turns ratio (as shown
in the Typical Performance Characteristics curves). For
a given turns ratio, as the input voltage drops, the input
resistance increases. This feature allows the LTC3108-1
to optimize power transfer from sources with a few ohms
of source resistance, such as a typical TEG. Note that a
lower source resistance will always provide more output
current capability by providing a higher input voltage
under load.
Peltier Cell (TEG) Suppliers
Peltier cells are available in a wide range of sizes and
power capabilities, from less than 10mm square to over
50mm square. They are typically 2mm to 5mm in height.
A list of Peltier cell manufacturers is given in Table 3.
Table 3. Peltier Cell Manufacturers
Fujitaka
www.fujitaka.com/pub/peltier/english/thermoelectric_power.html
FerroTec
www.ferrotec.com/products/thermal/modules
Laird Technologies
www.lairdtech.com
Marlow Industries
www.marlow.com
Micropelt
www.micropelt.com
Nextreme
www.nextreme.com
TE Technology
www.tetech.com/Peltier-Thermoelectric-Cooler-Modules.html
Tellurex
www.tellurex.com
Kryotherm
www.kryothermusa.com
applicaTions inForMaTion
Table 4. Recommended TEG Part Numbers by Size
MANUFACTURER 15mm × 15mm 20mm × 20mm 30mm × 30mm 40mm × 40mm
CUI Inc. (Distributor) CP60133 CP60233 CP60333 CP85438
Ferrotec 9501/031/030 B 9501/071/040 B 9500/097/090 B 9500/127/100 B
Fujitaka FPH13106NC FPH17106NC FPH17108AC FPH112708AC
Kryotherm TGM-127-1.0-0.8 LCB-127-1.4-1.15
Laird Technology PT6.7.F2.3030.W6 PT8.12.F2.4040.TA.W6
Marlow Industries RC3-8-01 RC6-6-01 RC12-8-01LS
Tellurex C2-15-0405 C2-20-0409 C2-30-1505 C2-40-1509
TE Technology TE-31-1.0-1.3 TE-31-1.4-1.15 TE-71-1.4-1.15 TE-127-1.4-1.05