On an Analog Controlled Precision Heat Power Source


On an Analog Controlled Precision Heat Power Source

Seilmayer, M.; Katepally, V.

The design of an analog controlled precision heat source is motivated by the measurement of the heat conductivity of liquids. In the framework of an online sensor which is able to measure physical properties like thermal conductivity or thermal diffusion in real time a precise and accurate heat source is required. Constant heat is applied to the material under test to acquire its different properties. Here, the common established methods of constant current or constant voltage may fail, because the heating resistor changes its resistance with temperature. The idea is to utilize a power monitor circuit like the LT2940, which contains an analog multiplier with a control loop around it. The initial design and its assumed uncertainties will be discussed. The first version of the power controller shows an outstanding performance in terms of precision in a steady state. Compared to conventional switching mode power sources the approach with an analog controlled heat source avoids EMI issues as well. The main goal of the present design is a precise heat source with less than 0.5% of error.

Keywords: precision heater; power control; analog controlled source

Permalink: https://www.hzdr.de/publications/Publ-25176
Publ.-Id: 25176