Temperature detecting apparatus
First Claim
1. A temperature detecting apparatus, comprising:
- a first transistor having an emitter, base and collector and having a thermal time constant with respect to ambient temperature;
a first current path including the emitter-collector path of said first transistor;
a semi-conductor element having an anode and a cathode and a rectifying PN junction therebetween, said semi-conductor element having a thermal time constant with respect to ambient temperature which is differentfrom the thermal time constant of said first transistor;
a second current path including said anode and cathode of said semi-conductor element, one of said anode and cathode terminals being coupled to said first transistor base; and
detection means responsive to current variations in said first or second current paths for detecting a rate of ambient temperature change which exceeds a predetermined value.
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Accused Products
Abstract
A temperature detecting apparatus having a first transistor connected in diode configuration or a first diode, with its forward current set in certain value. A second transistor has similar electrical characteristics as the first transistor or the first diode, with the anode or cathode of the first transistor or the first diode being connected to the base of the second transistor. The temperature difference between the first transistor or the first diode and the second transistor is detected by means of the variation of the collector current of the second transistor. In another embodiment, a third transistor matched to second one is used with common base connections. The first transistor is coupled to the common base coupling.
36 Citations
20 Claims
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1. A temperature detecting apparatus, comprising:
- a first transistor having an emitter, base and collector and having a thermal time constant with respect to ambient temperature;
a first current path including the emitter-collector path of said first transistor; a semi-conductor element having an anode and a cathode and a rectifying PN junction therebetween, said semi-conductor element having a thermal time constant with respect to ambient temperature which is differentfrom the thermal time constant of said first transistor; a second current path including said anode and cathode of said semi-conductor element, one of said anode and cathode terminals being coupled to said first transistor base; and detection means responsive to current variations in said first or second current paths for detecting a rate of ambient temperature change which exceeds a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 18, 19, 20)
- a first transistor having an emitter, base and collector and having a thermal time constant with respect to ambient temperature;
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16. A temperature detecting apparatus, comprising:
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a first transistor having an emitter, base and collector and having a first thermal time constant with respect to ambient temperature; a first current path including the emitter-collector path of said first transistor; a semi-conductor element coupled in diode configuration and having an anode and a cathode and a rectifying PN junction therebetween, said semi-conductor element having a second thermal time constant with respect to ambient temperature which differs from said first thermal time constant; a second current path including the anode and cathode of said semi-conductor element, one of said anode and cathode being coupled to said first transistor base; a second transistor having an emitter, base and collector and having a third thermal time constant with respect to ambient temperature which is substantially the same as said second thermal time constant, the base of said second transistor being coupled to the base of said first transistor; a third current path including the emitter-collector path of said second transistor; and means for comparing the currents through said first and third current paths to detect a rate of ambient temperature increase which exceeds a predetermined value. - View Dependent Claims (17)
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Specification