Voltage reference and temperature sensor

Abstract

A highly accurate voltage reference and temperature sensor circuit requires only several low-cost components in addition to a general-purpose microcontroller with an analog-to-digital converter. Unlike known circuits, the circuit disclosed does not rely on matching between a pair of semiconductor devices, as only a single semiconductor junction is used. All of the signal processing may be performed digitally.

Description

BACKGROUND[0001]Whenever voltages (or any parameters represented by voltages) need to be measured or digitized, it is necessary to have a voltage reference. Most electronic devices of any complexity have one or more references, for example in a signal processing chain or in the power supply circuitry.[0002]Depending on the desired overall system accuracy, the requirements for voltage references vary greatly; however it is clear that if well designed, a voltage reference should be relatively insensitive to deviations in its own power supply and to variations in its temperature.[0003]As with any other engineering challenge, the design of a voltage reference forces tradeoffs. Designing a voltage reference to be highly accurate despite changes in temperature, for example, usually makes it much more expensive.[0004]The designer of a voltage reference, in pursuit of temperature stability, will usually draw upon a bit of good luck, which is that nature will sometimes be so cooperative as t...

AI Technical Summary

Benefits of technology

[0029]Moreover, if a microcontroller with a built-in analog-to-digital converter is already a required part of the complete system, then a precise, high-accuracy, and low-power voltage reference can be formed by the mere addition of several low-cost components.

Problems solved by technology

As with any other engineering challenge, the design of a voltage reference forces tradeoffs.

Designing a voltage reference to be highly accurate despite changes in temperature, for example, usually makes it much more expensive.

In order to provide sufficiently-matched components, the designers have to resort to making the matched devices very large, so that the geometrical processing errors in the manufacture of the integrated circuits (ICs) have a diminishing effect on the matching; however, this increases the costs of manufacture, as more area is required on the surface of the IC die.

But the fact remains that a temperature gradient inside the IC will create errors, and these errors cannot be completely eradicated.

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