Miscellaneous active electrical nonlinear devices – circuits – and – External effect – Temperature
Reexamination Certificate
2000-04-19
2001-05-01
Callahan, Timothy P. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
External effect
Temperature
C327S574000, C374S170000
Reexamination Certificate
active
06225851
ABSTRACT:
The present invention concerns a temperature level detection circuit. In particular, the present invention relates to a detection circuit generating a temperature signal representative of a temperature greater than or less than a determined temperature threshold.
The detection circuit according to the present invention is intended in particular to be used in a battery protection circuit.
Circuits comparing a voltage to a reference voltage, which is stable in temperature, are known to those skilled in the art. In particular Swiss Patent No. 639 521 discloses a voltage level detection circuit used particularly to indicate the nearing of the end of life of batteries for electronic or electromechanical timepieces.
The voltage level detector circuit disclosed in this Patent compares an input voltage, namely the voltage across the battery terminals, to a reference level, and includes, on the one hand, means for generating a first, second and third diode voltage, formed by bipolar diode-connected transistors, in series with current sources, and on the other hands calculating means including capacitive elements and switching elements for selectively and sequentially connecting, during a first and second phase, the capacitive elements to the means generating the diode voltages and to an circuit input to which the input voltage is applied. The calculating means provide, during the second phase, a signal representative of the difference between the input voltage and the reference level defined from the sum of the first diode voltage and the product of the difference between the second and third diode voltages by a determined coefficient.
An object of the present invention is to provide a temperature threshold detection circuit allowing a voltage representative of the circuit temperature to a reference level to be compared.
The present invention therefore concerns a temperature level detection circuit the features of which are listed in claim
1
.
One advantage of the present invention lies in the fact that the temperature threshold of the detection circuit according to the present invention can be adjusted easily and accurately.
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patent: 639 521 (1983-11-01), None
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Freire R C S F et al: “A Highley Linear Single P-N Junction Temperature Sensor” IEEE Transactions on Instrumentation and Measurement, vol. 43, No. 2, Apr. 1, 1994, pp. 127-131, XP000438867; ISSN: 0018-9456.
Coughlin R F et al: “A System Approach to Linear Sensor Circuit Design” Electronic Engineering, vol. 65, No. 797, May. 1, 1993, p. 38 XP000362497; ISSN: 0013-4902.
Callahan Timothy P.
EM Microelectronic-Marin SA
Nguyen Hai L.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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