A High Precision Temperature Sensor with Correlated Double Sampling Function

A technology of temperature sensor and correlated double sampling, which is applied in the direction of instruments, control/regulation systems, and electric variable adjustment, can solve the problems of temperature sensor output error, high cost, deviation of detected temperature, etc., to eliminate triode error and improve Reliability and accuracy, effect of reducing output error

Active Publication Date: 2022-06-24
CHENGDU LIGHT COLLECTOR TECH
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  • Claims
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AI Technical Summary

Problems solved by technology

In practical applications, this kind of temperature sensor is mostly implemented by an external temperature sensor. Due to the fact that there is still a physical location difference with the CIS chip, there will be deviations in the actual detected temperature.
Moreover, most of the existing temperature sensors integrated in the CIS chip have a temperature voltage VPTAT (proportional to the absolute temperature) and a reference voltage VREF for comparison to generate an output of temperature information, because there will be process differences between chips Deviation will lead to an output error of the actual temperature sensor corresponding to each chip. This error can be completed by internal trimming. However, in mass production, due to the large number of chips, it is too expensive to adjust each chip individually. High, this adjustment method is almost impossible to achieve

Method used

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  • A High Precision Temperature Sensor with Correlated Double Sampling Function
  • A High Precision Temperature Sensor with Correlated Double Sampling Function
  • A High Precision Temperature Sensor with Correlated Double Sampling Function

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Embodiment 1

[0030] as attached figure 2 As shown, it is a reference voltage source with a general structure in the prior art, and many books and documents have related descriptions of this basic structure. Here, I will not repeat too much about its working principle, and directly give the first-order reference voltage VREF. The expression is

[0031]

[0032] where V REF is the reference voltage value, V BE3 is the emitter voltage of transistor Q3, R 1 , R 2 is the resistance value corresponding to the resistor R1 and the resistor R2, V T is the thermal voltage, and N is the ratio of the number of transistors Q1 and Q2. In the above expression, a negative and positive temperature characteristic voltage superposition is actually used to generate an output voltage with approximately zero temperature coefficient.

[0033] The current and temperature voltage values ​​of the branch where the temperature voltage VPTAT is located are:

[0034]

[0035]

[0036] Among them, I PT...

Embodiment 2

[0057] as attached Figure 5 As shown, this embodiment provides a high-precision temperature sensor with correlated double sampling function, wherein the analog-to-digital converter includes a ramp generator, a switch K1, a switch K2, a comparator and a counter, and the output end of the ramp generator is connected to compare The first input end of the comparator, one end of the switch K1 and the switch K2 are connected to the second input end of the comparator at the same time, the output end of the comparator is connected to the input end of the counter, and the output end of the counter outputs the count value; among them, the other end of the switch K1 Connect the temperature voltage VPTAT1, the other end of the switch K2 is connected to the temperature voltage VPTAT2, the input end of the ramp generator is connected to the reference voltage VREF, and the reference voltage VREF, the temperature voltage VPTAT1 and the temperature voltage VPTAT2 are output by the same referen...

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Abstract

The invention discloses a high-precision temperature sensor with correlated double sampling function, which includes a reference voltage source and an analog-to-digital converter, and the reference voltage VREF, temperature voltage VPTAT1 and temperature voltage VPTAT2 output by the reference voltage source are transmitted to the analog-to-digital converter The analog-to-digital converter quantizes the temperature voltage VPTAT1 and the temperature voltage VPTAT2 based on the reference voltage to generate digital temperature information; wherein the temperature voltage VPTAT1 and the temperature voltage VPTAT2 are output on the same branch of the reference voltage source. The invention provides a high-precision temperature sensor with correlated double sampling function, which reduces the output error of the temperature sensor and improves the precision of the temperature sensor.

Description

technical field [0001] The invention relates to the field of correlated temperature sensors, in particular to a high-precision temperature sensor with correlated double sampling function. Background technique [0002] CMOS image sensor chips have been developing continuously in recent years, and have gradually replaced CCD (Charge-coupled Device) and are widely used in various portable imaging electronic equipment, security monitoring equipment, vehicle electronics, etc. [0003] Many circuit modules and functions in a CMOS image sensor chip system are very sensitive to temperature. Therefore, it is necessary to change the operation configuration in real time according to the change of the chip temperature. For example, the dark level correction function uses an algorithm based on the actual temperature to control the output of the correction amount. In practical applications, this kind of temperature sensor is mostly realized by an off-chip temperature sensor. Since there...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G05F1/567
CPCG05F1/567
Inventor 陈飞蔡化芮松鹏高菊
Owner CHENGDU LIGHT COLLECTOR TECH
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