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CN-122016090-A - Temperature reading circuit, correction method, chip and electronic equipment

CN122016090ACN 122016090 ACN122016090 ACN 122016090ACN-122016090-A

Abstract

The application provides a temperature reading circuit, a correction method, a chip and electronic equipment, which relate to the technical field of temperature detection and comprise a digital operation circuit and a double-slope integral analog-to-digital conversion circuit, wherein the digital operation circuit comprises a voltage division circuit, a charge-discharge switching circuit and a counting control circuit; the voltage dividing circuit divides the band gap reference voltage to obtain a first reference voltage, a second reference voltage and a third reference voltage, the charge-discharge switching circuit determines a preset regulating value, the third reference voltage and the second reference voltage are connected in a first stage, the first temperature detection voltage and the second temperature detection voltage are connected in a third stage, the second reference voltage and the first reference voltage are connected in a second stage and a fourth stage, the counting control circuit counts to obtain a first measuring value and a second measuring value, the digital operation circuit calculates a first calibration value according to the first measuring value, the second measuring value and the preset regulating value, and the target temperature value is obtained according to the temperature offset value. So as to reduce the cost and improve the precision.

Inventors

  • Tang Rixian

Assignees

  • 珠海楠欣半导体科技有限公司

Dates

Publication Date
20260512
Application Date
20260212

Claims (10)

  1. 1. The temperature reading circuit is characterized by comprising a dual-slope integral analog-to-digital conversion circuit and a digital operation circuit, wherein the dual-slope integral analog-to-digital conversion circuit comprises a voltage division circuit, a charge-discharge switching circuit and a counting control circuit, and the charge-discharge switching circuit is respectively and electrically connected with the voltage division circuit and the counting control circuit; The voltage dividing circuit is used for dividing the band gap reference voltage to obtain a first reference voltage, a second reference voltage and a third reference voltage, wherein the difference value between the third reference voltage and the second reference voltage is equal to one third of the difference value between the first reference voltage and the second reference voltage, and the first reference voltage is larger than the second reference voltage; The charge-discharge switching circuit is used for determining a preset regulating value, and is also used for connecting the third reference voltage and the second reference voltage in a first stage so as to start charging, stopping charging when the counting control circuit counts to the preset regulating value, connecting the second reference voltage and the first reference voltage in a second stage so as to start discharging, stopping counting by the counting control circuit from zero when the output voltage of the counting control circuit is lower than a turnover threshold value, obtaining a first measured value, connecting the first temperature detection voltage and the second temperature detection voltage in a third stage so as to start charging, stopping charging when the counting control circuit counts to the preset regulating value, connecting the second reference voltage and the first reference voltage in a fourth stage so as to start discharging, and stopping counting by the counting control circuit when the output voltage of the counting control circuit is lower than the turnover threshold value, thereby obtaining a second measured value; The digital operation circuit is used for calculating a first calibration value according to the first measurement value, the second measurement value and the preset regulation value, and is also used for obtaining a current temperature value detected by the temperature reading circuit at normal temperature, calculating a difference value between the current temperature value and the normal temperature value to obtain a temperature offset value, and calculating a difference value between the first calibration value and the temperature offset value to obtain a target temperature value, wherein the normal temperature value is a digital quantity corresponding to normal temperature.
  2. 2. The temperature sensing circuit of claim 1, wherein the voltage divider circuit comprises a first resistor, a second resistor, a third resistor and a fourth resistor, wherein the resistance of the first resistor, the resistance of the third resistor and the resistance of the fourth resistor are equal, and the resistance of the second resistor is twice the resistance of the third resistor; The first end of the first resistor is connected to the band gap reference voltage, and the second end of the first resistor is electrically connected with the first end of the second resistor and is used as a first output end of the voltage dividing circuit for outputting the first reference voltage; The second end of the second resistor is electrically connected with the first end of the third resistor and is used as a third output end of the voltage dividing circuit for outputting the third reference voltage; the second end of the third resistor is electrically connected with the first end of the fourth resistor and is used as a second output end of the voltage dividing circuit for outputting the second reference voltage; the second end of the fourth resistor is grounded.
  3. 3. The temperature sensing circuit of claim 1, wherein the charge-discharge switching circuit comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a charge-discharge control switch, a reset switch, a fifth resistor, an integration capacitor, a first operational amplifier, and a second operational amplifier; The first end of the first switch is used for being connected with the first temperature detection voltage, the first end of the third switch is used for being connected with the first reference voltage, the first end of the fifth switch is used for being connected with the second reference voltage, and the second end of the first switch is electrically connected with the second end of the third switch, the second end of the fifth switch and the non-inverting input end of the first operational amplifier respectively; The first end of the second switch is used for being connected with the second temperature detection voltage, the first end of the fourth switch is used for being connected with the second reference voltage, the first end of the sixth switch is used for being connected with the third reference voltage, and the second end of the second switch is electrically connected with the second end of the fourth switch, the second end of the sixth switch and the non-inverting input end of the second operational amplifier respectively; The inverting input end of the first operational amplifier is electrically connected with the output end of the first operational amplifier and the first end of the charge-discharge control switch respectively, and the second end of the charge-discharge control switch is electrically connected with the first end of the fifth resistor; the second end of the fifth resistor is electrically connected with the inverting input end of the second operational amplifier, the first end of the integrating capacitor, the first end of the reset switch and the counting control circuit respectively; and the second end of the integrating capacitor is electrically connected with the second end of the reset switch, the output end of the second operational amplifier and the counting control circuit respectively.
  4. 4. The temperature sensing circuit of claim 3, wherein the count control circuit comprises a second comparator, a latch logic circuit, an oscillator, and a counter; the non-inverting input end of the second comparator is electrically connected with the output end of the second operational amplifier, the inverting input end of the second comparator is electrically connected with the second end of the fifth resistor, and the output end of the second comparator is electrically connected with the latch logic circuit which is respectively electrically connected with the counter and the charge-discharge switching circuit, and the oscillator is electrically connected with the counter; the oscillator is used for providing a clock signal; the comparator is used for comparing the output voltage of the charge-discharge switching circuit with the turnover threshold value and outputting a comparison result logic signal; The latch logic circuit is used for latching the comparison result logic signal to obtain a latch signal, so that the charge-discharge switching circuit controls the switch states of the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch according to the latch signal; the counter is used for counting according to the clock signal and the latch signal.
  5. 5. The temperature sensing circuit of claim 4, wherein a difference between the first temperature sensing voltage and the second temperature sensing voltage is a PTAT voltage.
  6. 6. The temperature sensing circuit of claim 5, wherein the charge-discharge switching circuit is specifically configured to control the third switch and the fourth switch to be in a conductive state, detect an absolute value of a difference between a voltage at the inverting input terminal of the first operational amplifier and a voltage at the inverting input terminal of the second operational amplifier, and obtain an error voltage; obtaining a temperature difference change voltage, wherein the temperature difference change voltage is the change amount of the PTAT voltage corresponding to each 1 ℃ of temperature change; and calculating the ratio between the error voltage and the temperature difference change voltage, and determining the preset regulating value.
  7. 7. The temperature sensing circuit of claim 4, wherein the digital operation circuit is configured to calculate the first calibration value according to the first measurement value, the second measurement value, and the preset adjustment value by a formula n3=n2- (3N 1-Nfix)/4, where N3 is the first calibration value, N1 is the first measurement value, N2 is the second measurement value, and Nfix is the preset adjustment value.
  8. 8. A temperature-readout-circuit correction method, characterized in that the temperature-readout-circuit correction method is applied to the temperature readout circuit according to claim 1, the temperature-readout-circuit correction method comprising: dividing the band gap reference voltage to obtain a first reference voltage, a second reference voltage and a third reference voltage, wherein the difference value between the third reference voltage and the second reference voltage is equal to one third of the difference value between the first reference voltage and the second reference voltage, and the first reference voltage is larger than the second reference voltage; Determining a preset adjustment value; The second reference voltage and the first reference voltage are connected in the second stage so that the charge-discharge switching circuit starts discharging, and the counting control circuit stops counting when the output voltage of the counting control circuit is lower than a turnover threshold value to obtain a first measurement value; The first temperature detection voltage and the second temperature detection voltage are connected in the third stage, so that the charge-discharge switching circuit starts to charge, and the charge is stopped when the counting control circuit counts to the preset regulating value; the second reference voltage and the first reference voltage are connected in a fourth stage so that the charge-discharge switching circuit starts discharging, the counting control circuit starts counting from zero, and when the output voltage of the counting control circuit is lower than the turnover threshold value, the counting control circuit stops counting to obtain a second measurement value; calculating a first calibration value according to the first measurement value, the second measurement value and the preset adjustment value; Acquiring a current temperature value detected by the temperature reading circuit at normal temperature, and calculating a difference value between the current temperature value and the normal temperature value to obtain a temperature offset value; And calculating the difference between the first calibration value and the temperature offset value to obtain a target temperature value, wherein the normal temperature value is a digital quantity corresponding to normal temperature.
  9. 9. A chip comprising the temperature sensing circuit according to any one of claims 1 to 7.
  10. 10. An electronic device comprising a chip as claimed in claim 9.

Description

Temperature reading circuit, correction method, chip and electronic equipment Technical Field The present application relates to the field of temperature detection technologies, and in particular, to a temperature readout circuit, a correction method, a chip, and an electronic device. Background The temperature detection function plays an important role in modern industry, agriculture, scientific research and daily life, and often needs to monitor the temperature of a closed environment, industrial equipment or electronic equipment, and take corresponding measures or alarm when the temperature is higher or lower. Referring to fig. 1, fig. 1 is a circuit architecture of a chip temperature acquisition circuit provided in the related art, as shown in fig. 1, a commonly used architecture for reading chip temperature includes an analog front-end circuit, an analog-to-digital conversion circuit and a digital circuit, wherein the analog front-end circuit generates a PTAT (Proportional to Absolute Temperature ) voltage V PTAT and a bandgap reference voltage V REF by using a bias circuit and a triode (Bipolar Junction Transistor, BJT), reads the PTAT voltage V PTAT by using the analog-to-digital conversion circuit (analog-Digital Conversion, ADC) as a reference voltage, and finally counts the temperature value by the digital circuit. In general, the greater the count value obtained by the digital circuit, the greater the corresponding temperature value, for example, the corresponding temperature value is 23 ℃ when the count value obtained by the digital circuit by the count process is 240, and the corresponding temperature value is 28 ℃ when the count value obtained by the digital circuit by the count process is 300. The analog-to-digital conversion circuit mostly adopts a sigma-delta architecture, and the architecture has the characteristics of high precision and low power consumption. In addition, after the chip is produced, temperature calibration is usually required, and two-point temperature calibration is usually adopted in the prior art, namely, two temperature points (for example, a high temperature point and a low temperature point) are selected for temperature calibration, so as to further improve the measurement accuracy of temperature. Although the analog-to-digital conversion circuit of the sigma-delta architecture has the advantages of high precision and low power consumption, the architecture occupies a larger layout area, so that the cost of a chip is higher, and the sigma-delta architecture is difficult to widely apply to a chip which is sensitive to the cost and needs a smaller layout area. Meanwhile, two-point calibration of the temperature also requires additional machine stations to perform high-temperature and low-temperature tests, so that the test cost is increased. In the related art, the dual-slope integral analog-to-digital conversion circuit (i.e. dual-slope ADC) provides a scheme with simple implementation and low cost, but the dual-slope integral analog-to-digital conversion circuit can introduce errors caused by operational amplifier imbalance, so that deviation occurs to temperature reading, and the measurement accuracy of the temperature is lower. Disclosure of Invention The application provides a temperature reading circuit, a correction method, a chip and electronic equipment, which are used for reducing the cost and improving the measurement accuracy of temperature. The application provides a temperature reading circuit, which comprises a double-slope integral analog-to-digital conversion circuit and a digital operation circuit, wherein the double-slope integral analog-to-digital conversion circuit comprises a voltage dividing circuit, a charge-discharge switching circuit and a counting control circuit, and the charge-discharge switching circuit is respectively and electrically connected with the voltage dividing circuit and the counting control circuit; The voltage dividing circuit is used for dividing the band gap reference voltage to obtain a first reference voltage, a second reference voltage and a third reference voltage, wherein the difference value between the third reference voltage and the second reference voltage is equal to one third of the difference value between the first reference voltage and the second reference voltage, and the first reference voltage is larger than the second reference voltage; The charge-discharge switching circuit is used for determining a preset regulating value, and is also used for connecting the third reference voltage and the second reference voltage in a first stage so as to start charging, stopping charging when the counting control circuit counts to the preset regulating value, connecting the second reference voltage and the first reference voltage in a second stage so as to start discharging, stopping counting by the counting control circuit from zero when the output voltage of the counting control circuit is lower than a turnover thre