All about peltier Module (TEC1-12706)

Many electronic components have a better signal-to-noise ratio at lower temperatures or are damaged when operating at temperatures above specifications. Similarly, certain chemical reactions must be kept at or below a certain temperature. A Peltier module can be used to solve thermal issues and cool objects below the ambient temperature in these applications, whereas a conventional heat sink and fan, cannot. Furthermore, Peltier modules and the appropriate control circuit allow an object to be kept at a constant temperature even when subjected to rapidly fluctuating thermal loads.

Peltier Module Basics

Peltier modules are made up of two external ceramic plates that are separated by semiconductor pellets. When a current is passed through the semiconductor pellets, one of the plates absorbs heat and the other plate dissipates heat (becomes hotter). This technical paper contains more information on the construction and operation of Peltier modules.

Heat Transfer Through Peltier Modules

The amount of heat transferred from the cold side to the hot side by a Peltier module is denoted Q and is specified in Watts. This parameter can be the heat generated by an object to be cooled or the heat conducted from the object to the ambient environment. Peltier modules are incapable of absorbing thermal energy. Peltier modules only transfer thermal energy, and the energy transferred must be dissipated on the module's hot side.

Temperature Difference Across Peltier Modules

The temperature difference specified in a TEC1-12706 Peltier module is measured on the module's two ceramic plates outside surfaces. It is critical to determine whether or not there is a temperature difference between the Peltier module plates and the external system temperatures of interest. 

The temperature of the Hot Side of Peltier Modules

Peltier module characteristics vary with operating temperature. CUI Devices, for example, provides specification data for more than one operating temperature. Because specification data for the application's specific operating temperatures is unlikely to be available, the closest available data should be used.

Surface Area of Peltier Modules

Peltier modules' surface area is typically specified based on the area of the object to be cooled or the area available for heat dissipation. A low thermal impedance heat spreader can compensate for an area mismatch between the available area and the area of the Peltier module. Aluminum or copper can be used to make a simple heat spreader.

Required Operating Current

Peltier modules, like LEDs, are current-driven devices. The most convenient way to achieve the desired operating parameters is to drive the module with a controlled current source and allow the current source to provide the required load voltage. This is equivalent to applying a specific voltage to a voltage-driven device and then allowing the voltage source to provide the necessary current.

Peltier modules can be driven by voltage sources, but this makes accurate control of the heat flow and temperature difference across the module more difficult.

Conclusion

Peltier modules can be an excellent solution when it is necessary to cool an object below its ambient temperature or to keep an object at a specific temperature. To ensure a successful design, choose a vendor who offers a variety of Peltier modules as well as adequate characterization data. In addition to working with a trustworthy vendor, it is critical to understand the nuances of module implementation and operation, such as the fundamentals outlined in this post.