Datasheet LTC3108 (Analog Devices) - 13

link to page 12 link to page 5 link to page 13 LTC3108
APPLICATIONS INFORMATION
temperature differential between the plates. When used in source resistance will always provide more output current this manner, a Peltier cel is referred to as a thermoelectric capability by providing a higher input voltage under load. generator (TEG).
Peltier Cell (TEG) Suppliers
The low voltage capability of the LTC3108 design allows it to operate from a TEG with temperature differentials as Peltier cells are available in a wide range of sizes and low as 1°C, making it ideal for harvesting energy in appli- power capabilities, from less than 10mm square to over cations in which a temperature difference exists between 50mm square. They are typically 2mm to 5mm in height. two surfaces or between a surface and the ambient tem- A list of Peltier cell manufacturers is given in Table 3. perature. The internal resistance (ESR) of most cells is
Table 3. Peltier Cell Manufacturers
in the range of 1Ω to 5Ω, allowing for reasonable power CUI, Inc. transfer. The curves in Figure 2 show the open-circuit www.cui.com (Distributor) output voltage and maximum power transfer for a typi- Fujitaka www.fujitaka.com/pub/peltier/english/thermoelectric_power.html cal Peltier cell (with an ESR of 2Ω) over a 20°C range of Ferrotec temperature differential. www.ferrotec.com/products/thermal/modules Kryotherm
TEG Load Matching
www.kryothermusa.com Laird Technologies The LTC3108 was designed to present a minimum input www.lairdtech.com resistance (load) in the range of 2Ω to 10Ω, depending Marlow Industries on input voltage and transformer turns ratio (as shown www.marlow.com Micropelt in the Typical Performance Characteristics curves). For www.micropelt.com a given turns ratio, as the input voltage drops, the input Nextreme resistance increases. This feature allows the LTC3108 to www.nextreme.com optimize power transfer from sources with a few ohms of TE Technology www.tetech.com/Peltier-Thermoelectric-Cooler-Modules.html source resistance, such as a typical TEG. Note that a lower Tellurex www.tellurex.com
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 Rev. D For more information www.analog.com 13 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts