Abstract
A novel design of a circuit used for NTC thermistor linearization is
proposed. The novelty of the proposed design consists in a specific
combination of two linearization circuits, a serial-parallel resistive
voltage divider and a two-stage piecewise linear analog-to-digital
converter. At the output of the first linearization circuit the
quasi-linear voltage is obtained. To remove the residual voltage
nonlinearity, the second linearization circuit, i.e., a two-stage
piecewise linear analog-to-digital converter is employed. This circuit is
composed of two flash analog-to-digital converters. The first
analog-to-digital converter is piecewise linear and it is actually
performing the linearization, while the second analog-to-digital converter
is linear and it is performing the reduction of the quantization error
introduced by the first converter. After the linearization is performed,
the maximal absolute value of a difference between the measured and real
temperatures is 0.014°C for the temperature range between −25 and 75°C,
and 0.001°C for the temperature range between 10 and 40°C.
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