Stmicroelectronics International N.v.

Pijush Kanti Panja

Atul Dwivedi

Kallol Chatterjee

Gautam Dey Kanungo

Rajesh Yadav

A method for determining temperature of a chip, includes generating a first voltage and a second voltage using a pair of bipolar-junction transistors, and generating a third voltage using another bipolar-junction transistor. When a most recent bit of a bitstream is a logic-zero, the difference between the first and second voltages is sampled using a switched-capacitor input-sampling circuit, and a difference between the first and second voltages is integrated, to produce a proportional-to-absolute-temperature voltage. The proportional-to-absolute-temperature voltage is quantized to produce a next bit of the bitstream. When the most recent bit of the bitstream is a logic-one, the third voltage is sampled using the switched-capacitor input-sampling circuit, and the third voltage is integrated, to produce a complementary-to-absolute-temperature voltage. The complementary-to-absolute-temperature voltage is quantized to produce a next bit of the bitstream. The bitstream is filtered and decimated to produce an output code representative of the temperature of the chip.

Method for implementing Vptat multiplier in high accuracy thermal sensor

Circuitry generates base-to-emitter voltages (Vbe, Vbe) of two BJTs biased at different current densities, a base-to-emitter voltage (Vbe) of a BJT biased so Vbe is complementary to absolute temperature and has a curved non-linearity across temperature, and base-to-emitter voltages (Vbe_c, Vbe_c) of two BJTs biased by a temperature independent constant current and a current proportional to absolute temperature so Vbe_c−Vbe_c has the same but opposite curved non-linearity across temperature as Vbe. A sampling circuit samples these voltages and provides them to inputs of a loop filter. Filter outputs are quantized to produce a bitstream. The sampling circuit: when the received bit of the bitstream is zero, causes integration of Vbe−Vbeto produce a voltage proportional to absolute temperature (αΔVbe); and when the received bit of the bitstream is one, causes integration of Vbe_c−Vbe_Vbe_c to produce a negative voltage complementary to absolute temperature −Vbe_c without non-linearity across temperature.

Controlled curvature correction in high accuracy thermal sensor

A temperature sensing circuit a switched capacitor circuit selectively samples ΔVbe and Vbe voltages and provides the sampled voltages to inputs of an integrator. A quantization circuit quantizes outputs of the integrator to produce a bitstream. When a most recent bit of the bitstream is a logic zero, operation includes sampling and integration of ΔVbe a first given number of times to produce a voltage proportional to absolute temperature. When the most recent bit of the bitstream is a logic one, operation includes cause sampling and integration of Vbe a second given number of times to produce a voltage complementary to absolute temperature. A low pass filter and decimator filters and decimates the bitstream produced by the quantization circuit to produce a signal indicative of a temperature of a chip into which the temperature sensing circuit is placed.

A reference current generator circuit generating a reference current that is proportional to absolute temperature as a function of a difference between bias voltages of first and second transistors. A voltage generator generates an input voltage from the reference current by applying the reference current that is proportional to absolute temperature through a plurality of transistors coupled in series between the bias voltage of the second transistor and ground, with the input voltage being generated at a node between given adjacent ones of the plurality of transistors. The input voltage is complementary to absolute temperature. A differential amplifier is biased by a current derived from the reference current and generates a temperature insensitive output reference voltage from the input voltage and a voltage proportional to absolute temperature.

Sub-bandgap compensated reference voltage generation circuit

A sub-bandgap reference voltage generator includes a reference current generator generating a reference current (proportional to absolute temperature), a voltage generator generating an input voltage (proportional to absolute temperature) from the reference current, and a differential amplifier. The differential amplifier is biased by the reference current and has an input receiving the input voltage and a resistor generating a voltage proportional to absolute temperature summed with the input voltage to produce a temperature insensitive output reference voltage. The reference current generator may generate the reference current as a function of a difference between bias voltages of first and second transistors. The voltage generator may generate the input voltage by applying the current proportional to absolute temperature through a plurality of transistors coupled in series between the bias voltage of the second transistor and ground, and tapping a node between given adjacent ones of the plurality of transistors.

A first signal received at a first transistor is compared to a second signal received at a second transistor taking into account a hysteresis value to generate a comparison output. At least one of the first and second transistors has a floating bulk. A switching circuit selectively applies first and second bulk bias voltages to the floating bulk of the first or second transistor in dependence on the comparison output. A third and fourth input signals, setting the hysteresis value, are received at third and fourth transistors and compared to generate differential outputs. At least one of the third and fourth transistors has a floating bulk. A differential amplifier determines a difference between the differential outputs for application to the floating bulk of the at least one of the third and fourth transistor and further for use as one of the first and second bulk bias voltages.

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West Bengal, India

Pijush Kanti Panja