Temperature detecting device
First Claim
1. A temperature detecting device comprising:
- a constant voltage circuit and a series circuit of a temperature detecting means and a constant current circuit connected to a power source in parallel, a resistance ladder circuit connected between an output terminal of said constant voltage circuit and one terminal of said power source, means connecting an output terminal of said resistance ladder circuit to a first input terminal of a differential amplifier, and means connecting a second input terminal of said differential amplifier to a connection point of said temperature detecting means and the constant current circuit, whereby a temperature signal is produced as an output voltage of said differential amplifier.
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Abstract
A temperature detecting device comprises a semiconductor diode temperature sensor having a resistance characteristic which varies with variations in temperature, and a constant current circuit connected in series. A power source is connected in parallel with the series circuit and connected in parallel with a constant voltage circuit. A resistance ladder circuit is connected between an output terminal of the constant voltage circuit and one terminal of the power source, and an output terminal of the resistance ladder circuit is connected to a first input terminal of a differential amplifier. A second input terminal of the differential amplifier is connected to a connection point of the semiconductor diode and the constant current circuit. In operation, the voltage drops across cumulatively successive resistors of the resistance ladder circuit are compared with the voltage drop across the semiconductor diode temperature sensor by the differential amplifier and in response to a favorable comparison, the output logic state of the differential amplifier changes to thereby provide an output temperature signal.
55 Citations
10 Claims
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1. A temperature detecting device comprising:
- a constant voltage circuit and a series circuit of a temperature detecting means and a constant current circuit connected to a power source in parallel, a resistance ladder circuit connected between an output terminal of said constant voltage circuit and one terminal of said power source, means connecting an output terminal of said resistance ladder circuit to a first input terminal of a differential amplifier, and means connecting a second input terminal of said differential amplifier to a connection point of said temperature detecting means and the constant current circuit, whereby a temperature signal is produced as an output voltage of said differential amplifier.
- View Dependent Claims (2, 3, 4)
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5. A temperature detecting device for detecting temperature comprising:
- temperature detecting means having a resistance characteristic which varies with variations in temperature;
constant current circuit means for flowing a constant current through the temperature detecting means to develop a voltage drop thereacross representative of the temperature to be detected; and
electric circuit means for sequentially comparing the voltage drop across the temperature detecting means with a plurality of predetermined reference voltage drops each of which corresponds to a different known temperature and producing an output temperature signal in response to a favorable comparison. - View Dependent Claims (6, 7, 8, 9, 10)
- temperature detecting means having a resistance characteristic which varies with variations in temperature;
Specification