| CPC G01K 7/24 (2013.01) [G01K 7/42 (2013.01); G01K 2219/00 (2013.01)] | 14 Claims |
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1. An electronic device for estimating a temperature value of a thermistor, comprising:
a first signal port, to be coupled to a first terminal of the thermistor;
a second signal port, to be coupled to a second terminal of the thermistor;
an analog-to-digital converter; and
a processing circuit, disposed and coupled between the first signal port and the analog-to-digital converter, the processing circuit comprising:
a first resistor unit, coupled between a first intermediate node and a supply voltage provided for the processing circuit;
a second resistor unit, coupled between the first intermediate node and a second intermediate node, the second intermediate node being coupled to the first signal port;
a third resistor unit, coupled between the second intermediate node and a first switch unit;
the first switch unit, coupled between the third resistor unit and a ground level; and
a second switch unit, coupled between the second signal port and the ground level;
wherein when the thermistor is coupled to the first signal port of the electronic device, the processing circuit is arranged to operate in a first switching condition to detect and generate a first voltage difference to the analog-to-digital converter, to operate in a second switching condition to detect and generate a second voltage difference to the analog-to-digital converter; the analog-to-digital converter is arranged to determine a resistance value of the thermistor based on the first voltage difference compared to the second voltage difference and to generate the estimated temperature value according to the determined resistance value; the first voltage difference is generated by the processing circuit in the first switching condition in which the first switch unit becomes closed and the second switch unit becomes open; the second voltage difference is generated by the processing circuit in the second switching condition in which the first switch unit becomes open and the second switch unit becomes closed; before being coupled to the thermistor, the first signal port and the second signal port are selectively coupled to two terminals of a reference resistor unit having a reference resistance value for estimating a process variation, and the processing circuit is arranged to detect and generate another first voltage difference to the analog-to-digital converter when the processing circuit operates in the first switching condition, to detect and generate another second voltage difference to the analog-to-digital converter when the processing circuit operates in the second switching condition; and, the analog-to-digital converter is arranged to determine a variation of a resistor unit comprised within the processing circuit according to the another first voltage difference and the another second voltage difference.
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