During his many years in the electronics industry working in design, sales, and marketing, Bruce Rose has focused on analog circuits and power delivery. His range of work experience includes organizing and chairing international workshops, publishing and presenting in more than 40 technical conferences and journals, and having been awarded seven patents.
While he enjoys his time at work, Bruce further enjoys the time he is able to spend with his family hiking, biking, and canoeing as well as pursuing his passion of full scale and model aviation. Keep current with the latest product releases, technical resources and company updates from CUI Devices. Toggle navigation. Cable Assemblies. Rotary Encoders. Stepper Servo Motors. Current Sensors. Ultrasonic Sensors. DIP Switches. Push Button Switches.
Slide Switches. Tactile Switches. Thermal Management. Dc Fans. Heat Sinks. Peltier Devices. Thermal Accessories. Parametric Search. From there, the required current and associated drive voltage can be determined.
The most important thermal conditions are the heat to be transferred across the module, the maximum temperature across the Peltier module, and the maximum hot side temperature of the module. Peltier manufacturers typically offer a range of thermoelectric modules which will serve a given set of thermal conditions and enable a range of supply current and voltage operating values.
For a more detailed discussion regarding selecting a Peltier device, please read our "How to Select a Peltier Module" blog post. Peltier modules are most easily characterized by their current draw.
The level of current required for the application is determined by evaluating the selected Peltier device's characteristic curves. Dominant parameters affecting the required current are the thermal power to be transferred, the temperature to be maintained, and the operating temperature of the module. Although the Peltier module characteristics are determined by the current, a controlled voltage source can be used to power the device and provide the desired operating current. The applied voltage required to supply the desired current can be determined by viewing the specification curves of the selected thermoelectric module see example.
In some applications, the intention is to operate the Peltier module in such a way that the maximum amount of cooling is continuously delivered. In these instances, a constant voltage is applied to the Peltier device and the resultant load current and cooling can be determined based upon the characterization graphs in the datasheets.
However, in other applications, Peltier modules are implemented to maintain an object at a controlled temperature. These designs utilize a thermal sensor, such as a thermocouple, a solid-state temperature sensor, or an infrared sensor to monitor the temperature of the object.
The temperature data is fed back to the power source via a thermal control loop to adjust the voltage or current applied to the Peltier module.
A common method to control the voltage applied to the thermoelectric module is to include a Pulse Width Modulation PWM stage on the output of a standard power supply.
The external PWM stage is necessary because many power supplies do not have the ability to easily adjust the output voltage over a wide range. Higher ripple voltages will not damage the Peltier module, but it will reduce its Coefficient of Performance COP and may cause electrical noise issues in the object being cooled. The design of the thermal control loop can be implemented in many forms due to the low loop bandwidth required.
In addition, polarity of the controlled voltage or current will need to be reversible if the temperature control system will be required to both cool and heat the object. Peltier devices transfer heat across the module when electrical power is supplied.
A voltage is applied across joined conductors to create an electric current. When the current flows through the junctions of the two conductors, heat is removed at one junction and cooling occurs. Heat is deposited at the other junction. The main application of the Peltie r effect is cooling. However, the Peltier effect can also be used for heating or control of temperature.
In every case, a DC voltage is required. When the current flows through the junctions of the two conductors, heat is removed at one junction and cooling occurs. Heat is deposited at the other junction. The main application of the Peltier effect is cooling. However the Peltier effect can also be used for heating or control of temperature. In every case, a DC voltage is required. A single stage thermoelectric cooler can produce a maximum temperature difference of about 70 degrees Celsius.
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