Temperature sensor applied to metering ammeter and temperature trimming method thereof

Abstract

The invention provides a temperature sensor applied to a metering ammeter. The temperature sensor comprises an analog circuit portion, a digital circuit portion and a user ARM portion. The analog circuit portion comprises a positive temperature coefficient current generator in direct-proportion current bias with an absolute temperature, a bias current mirror array, a low-temperature drift coefficient reference current source, a temperature-sensitive transistor and an analog-to-digital conversion integrator. The digital circuit portion comprises a switch control logic, a digital code output, a digital counter and a shift register. The analog-to-digital conversion integrator has a sampling capacitor and an integrating capacitor, of which the capacitance is same; and bias current of the temperature-sensitive transistor is biased by six unit current mirrors in turns in a proportion of 5:1. According to a temperature trimming method for the temperature sensor, the number of the bias current mirrors is 6, wherein 5 paths of currents are used for coarse tuning, and the other one path of current is used for fine tuning; when the output bias of the counter is relatively large, the 5 paths of coarse-tuning currents are used; and when the output of the counter is between the two paths of unit currents, fine tuning is used.

Description

technical field [0001] The invention relates to a temperature sensor, in particular to a temperature sensor used in a meter and a temperature trimming method. Background technique [0002] At present, there are more and more important places that need to strictly control the temperature, such as entertainment places, hotels, large supermarkets, grain depots, boilers, computer rooms, etc. These places generally need to set up a temperature monitoring system based on temperature sensors, so that It can protect specific assets or ensure the smooth operation of the system. In addition, in tunnels, railways, subways, airports, cabins and other transportation areas and dangerous goods areas such as oil tanks, coal bunkers, cargo holds, military factories and ammunition depots, temperature monitoring is usually It is the most basic detection element, and there are many patented technologies for this at home and abroad. However, the technology development of temperature sensors use...

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Problems solved by technology

[0014] The purpose of the present invention is to overcome the deficiencies in the prior art above, to provide a high-precision temperature sensor used in metering meters, to realize the gain coefficient in the analog circuit through the user's calculation in ARM, and to avoid the capacitance ratio in the analog circuit. If the gain is too large, the gain change is inaccurate. At the same time, it makes the analog circuit layout easier to match, greatly reduces the chip area of ​​the analog circuit, and reduces the cost. At the same time, the shift register is used to rotate the analog current mirror array, and the average dynamic matching ideas to reduce errors caused by mismatch

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