PN-junction temperature sensing apparatus
First Claim
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1. A PN-junction temperature sensing apparatus comprising:
- a plurality of current sources, wherein each current source comprises a p-type MOSFET transistor being source connected to a supply voltage;
a band gap based current reference, which is mirrored in the plurality of current sources;
switches having two selectable outputs controlled by a digital processor, wherein each switch is connected with the drain of each current source and wherein a first output of each switch is connected to an anode of a PN-junction thermal sensor and a second output of each switch is connected to an anode of a sink diode and wherein the cathodes of both components are connected to a common level, wherein the number of current sources connected to the switches consists of an odd number of three or more, and wherein each of the current sources exhibits a current gain ratio with respect to the band gap based current reference of 1;
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an integrated A/D converter to digitize the voltage across the PN-junction sensor, wherein the value of the digitized voltage is stored in a memory of the digital processor.
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Abstract
A PN-junction temperature sensing apparatus for applying input signals to a semiconductor device and measuring temperature-dependent output signals has an odd number of current sources (1, 2, n) switches (5, 6, 7) with selectable outputs to connect the current sources (5, 6, 7) with a thermal sensor (12) or a sink diode (13) and an A/D converter (17) to digitize the measured voltage of the thermal sensor (12). A digital processor (18) controls the switches (5, 6, 7) and stores the digitized voltage values in a memory. Provided algorithms allow the usage of these values to provide a calibrated measurement of temperature and also sensor life estimation.
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Citations
20 Claims
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1. A PN-junction temperature sensing apparatus comprising:
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a plurality of current sources, wherein each current source comprises a p-type MOSFET transistor being source connected to a supply voltage; a band gap based current reference, which is mirrored in the plurality of current sources; switches having two selectable outputs controlled by a digital processor, wherein each switch is connected with the drain of each current source and wherein a first output of each switch is connected to an anode of a PN-junction thermal sensor and a second output of each switch is connected to an anode of a sink diode and wherein the cathodes of both components are connected to a common level, wherein the number of current sources connected to the switches consists of an odd number of three or more, and wherein each of the current sources exhibits a current gain ratio with respect to the band gap based current reference of 1;
1;an integrated A/D converter to digitize the voltage across the PN-junction sensor, wherein the value of the digitized voltage is stored in a memory of the digital processor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 19)
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10. A PN-junction temperature sensing apparatus comprising:
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a plurality of current sources, wherein each current source comprises a p-type MOSFET transistor being source connected to a supply voltage; a band gap based current reference, which is mirrored in the plurality of current sources; switches having two selectable outputs controlled by a digital processor, wherein each switch is connected with the drain of each current source and wherein a first output of each switch is connected to an anode of a PN-junction thermal sensor and a second output of each switch is connected to an anode of another PN-junction thermal sensor device and wherein the cathodes of both components are connected to a common level, wherein the number of current sources connected to the switches consists of an odd number of three or more, and wherein each of the current sources exhibits a current gain ratio with respect to the band gap based current reference of 1;
1;an integrated A/D converter to digitize the voltage across the PN-junction sensor, wherein the value of the digitized voltage is stored in a memory of the digital processor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 20)
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Specification