US 11,867,572 B2
Method for implementing Vptat multiplier in high accuracy thermal sensor
Pijush Kanti Panja, Singur (IN); Kallol Chatterjee, Kolkata (IN); and Atul Dwivedi, Benares (IN)
Assigned to STMicroelectronnternational N.V., Geneva (CH)
Filed by STMicroelectronics International N.V., Geneva (CH)
Filed on Nov. 8, 2021, as Appl. No. 17/521,123.
Claims priority of provisional application 63/129,244, filed on Dec. 22, 2020.
Prior Publication US 2022/0196485 A1, Jun. 23, 2022
Int. Cl. H03K 17/14 (2006.01); G01K 7/14 (2006.01); G01K 7/01 (2006.01); H03K 19/018 (2006.01); H03M 1/12 (2006.01)
CPC G01K 7/14 (2013.01) [G01K 7/01 (2013.01); H03K 17/14 (2013.01); H03K 19/018 (2013.01); H03M 1/1245 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A temperature sensing circuit, comprising:
voltage generation circuitry comprising:
first and second bipolar junction transistors having coupled collectors and bases, and biased at different current densities; and
a third bipolar junction transistor having its collector coupled to its base, the third bipolar junction transistor biased by a calibrated current;
an integrator;
a switched capacitor circuit configured to selectively sample voltages produced by the voltage generation circuitry and provide the sampled voltages to inputs of the integrator;
a quantization circuit configured to quantize outputs of the integrator to produce a bitstream;
wherein the switched capacitor circuit cooperates with the integrator under control of the bitstream to:
when a most recent bit of the bitstream is a logic zero, cause sampling and integration of a difference between a base-emitter voltage of the first bipolar junction transistor and a base-emitter voltage of the second bipolar junction transistor a first number of times to thereby produce a voltage proportional to absolute temperature; and
when the most recent bit of the bitstream is a logic one, cause sampling and integration of a base-emitter voltage of the third bipolar junction transistor a second number of times to thereby produce a voltage complementary to absolute temperature; and
a low pass filter and decimator configured to filter and decimate 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.