DIE TEMPERATURE SENSOR CIRCUIT
First Claim
1. A temperature sensor, comprising:
- an amplifier, the amplifier including a first bipolar transistor and a second bipolar transistor configured as an input differential pair of the amplifier, the first bipolar transistor having a first collector current density, and the second bipolar transistor having a second collector current density different from the first collector current density of the first bipolar transistor;
wherein the amplifier is configured such that, when the first and second bipolar transistor having a same temperature, an input offset voltage is equal to a voltage difference between a base-to-emitter voltage of the first bipolar transistor and a base-to-emitter voltage of the second bipolar transistor, such voltage difference being proportional to absolute temperature; and
an output stage for amplifying such voltage difference, wherein the temperature sensor generates, at an output terminal, a voltage VOUT that varies proportionally with temperature of the temperature sensor.
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Accused Products
Abstract
A die temperature sensor circuit (200) includes an amplifier (203) that has first and second stages of amplification and that has bipolar transistors (201 and 202) as an input differential pair. The bipolar transistors have different current densities. A difference between base-emitter voltages of the bipolar transistors is proportional to absolute temperature of the bipolar transistors. The bipolar transistors also provide amplification for the first stage of amplification. Multiple feedback loops maintain a same ratio between the current densities of the bipolar transistors over temperature by changing collector currents that bias the bipolar transistors. A feedback loop includes a second stage of amplification and such feedback loop cancels effect that base currents of the bipolar transistors have on an output signal of the die temperature sensor circuit.
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Citations
20 Claims
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1. A temperature sensor, comprising:
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an amplifier, the amplifier including a first bipolar transistor and a second bipolar transistor configured as an input differential pair of the amplifier, the first bipolar transistor having a first collector current density, and the second bipolar transistor having a second collector current density different from the first collector current density of the first bipolar transistor; wherein the amplifier is configured such that, when the first and second bipolar transistor having a same temperature, an input offset voltage is equal to a voltage difference between a base-to-emitter voltage of the first bipolar transistor and a base-to-emitter voltage of the second bipolar transistor, such voltage difference being proportional to absolute temperature; and an output stage for amplifying such voltage difference, wherein the temperature sensor generates, at an output terminal, a voltage VOUT that varies proportionally with temperature of the temperature sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An integrated circuit, comprising:
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a circuit-supporting substrate, the circuit-supporting substrate including; a differential pair including a first bipolar transistor and a second bipolar transistor, the first and second bipolar transistor disposed near each other on the circuit-supporting substrate so that they have nearly a same temperature, the first and second bipolar transistors having different current densities, the differential pair for generating a signal proportional to absolute temperature (PTAT), the signal being a voltage difference between base-to-emitter voltage of the first bipolar transistor and base-to-emitter voltage of the second bipolar transistor; a first feedback loop, coupled to the differential pair, to maintain a value for collector current through of the first bipolar transistor, and a second feedback loop, coupled to the differential pair, to maintain a value for collector current of the second bipolar transistor, wherein the first and second feedback loops maintain a ratio between current densities of the first and second bipolar transistors regardless of temperature; and an output terminal for providing an output signal that is representative of temperature of the integrated circuit. - View Dependent Claims (11, 12, 13)
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14. A temperature sensor circuit, comprising:
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a first amplification stage including an input differential pair, the input differential pair including a first bipolar transistor having a base-to-emitter voltage and a second bipolar transistor having a base-to-emitter voltage, the first amplification stage configured so that the first and second bipolar transistors can have a same temperature when operating, the input differential pair for generating a signal proportional to absolute temperature (PTAT) and for amplifying a differential input signal; a first feedback loop, coupled to the differential pair, for controlling a collector current of the first bipolar transistor; and a second feedback loop, coupled to the differential pair, for controlling a collector current of the second bipolar transistor, the second feedback loop including; a second amplification stage for amplifying a PTAT signal from the first amplification stage and for providing an output signal proportional to absolute temperature at an output terminal, the second amplification stage including an output transistor having a control electrode coupled to the first amplification stage, a first current electrode coupled to a first power supply voltage terminal, and a second current electrode, and a resistance divider comprising resistive element R1, resistive element R2 and resistive element R3, respectively, connected in series, with one end of the series coupled the second current electrode of the output transistor and with another end of the series coupled to a second power supply voltage terminal, and an output terminal at the second current electrode for providing a signal representative of absolute temperature of the temperature sensor circuit, wherein the first and second feedback loops maintain a constant ratio between collector current densities of the first and second bipolar transistors, regardless of temperature. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification