Temperature sensing circuit
First Claim
1. A temperature threshold sensing circuit for an integrated circuit comprising:
- a semiconductor junction device providing a VBE reference,a proportional-to-absolute-temperature (PTAT) current generator comprising;
a resistor and a PTAT current source connected in a first series circuit to terminals of a source of supply voltage, anda further PTAT current source connected in a second series circuit with the semiconductor junction device to said terminals of the supply voltage source, and wherein said temperature threshold sensing circuit further comprises;
means coupled to said resistor and to said semiconductor junction device for detecting whether a voltage developed across the resistor exceeds the VBE reference and for generating an output signal which thereby indicates whether the temperature of the integrated circuit is above or below a predetermined threshold temperature, and wherein the detecting means comprise a voltage comparator for comparing voltage drops across the resistor and the semiconductor junction device.
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Accused Products
Abstract
In order to sense the temperature of an integrated circuit chip, a semiconductor junction device (D1) integrated on the chip is used to generate a first signal (V1) having a known variation with temperature. A second signal (V2) is generated by passing a PTAT current (I2) through a resistor (R1) so that the second signal (V2) has a known variation with temperature which is opposite in sign to that of the first signal (V1). The two signals are compared (42) to generate an output signal (OT) which is dependent on whether the temperature of the chip is below or above a predetermined threshold temperature. The current (I1) through the junction device (D1) is also PTAT, which provides a more accurate definition of the threshold temperature in terms of integrated circuit parameters.
76 Citations
22 Claims
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1. A temperature threshold sensing circuit for an integrated circuit comprising:
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a semiconductor junction device providing a VBE reference, a proportional-to-absolute-temperature (PTAT) current generator comprising; a resistor and a PTAT current source connected in a first series circuit to terminals of a source of supply voltage, and a further PTAT current source connected in a second series circuit with the semiconductor junction device to said terminals of the supply voltage source, and wherein said temperature threshold sensing circuit further comprises; means coupled to said resistor and to said semiconductor junction device for detecting whether a voltage developed across the resistor exceeds the VBE reference and for generating an output signal which thereby indicates whether the temperature of the integrated circuit is above or below a predetermined threshold temperature, and wherein the detecting means comprise a voltage comparator for comparing voltage drops across the resistor and the semiconductor junction device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 19)
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- 17. A circuit as claimed in claim in 14 wherein the integrated circuit includes a power semiconductor device whose temperature is to be monitored and said second and third semiconductor junction devices are integrated in said integrated circuit in close thermal coupling relationship to the power semiconductor device.
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20. A temperature sensing circuit for an integrated circuit chip comprising:
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a resistor and a proportional-to-absolute-temperature (PTAT) current source connected in a first series circuit to terminals of a source of supply voltage, a semiconductor junction device integrated on the chip to provide a VBE reference, a further PTAT current source connected in a second series circuit with the semiconductor junction device to said terminals of the supply voltage source thereby to generate a first voltage having a given variation with temperature, said first series circuit generating a second voltage having a given inverse temperature variation relative to the temperature variation of said first generated voltage, and a voltage comparator which receives and compares said first and second voltages to derive an output signal which is determined by the temperature of the chip. - View Dependent Claims (21, 22)
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Specification