Direct-to-digital temperature sensor

Details Direct-to-digital temperature sensor Direct-to-digital temperature sensor

1998-09-25

2001-04-10

Jackson, Stephen W. (Department: 2836)

Electricity: electrical systems and devices

Safety and protection of systems and devices

Circuit interruption by thermal sensing

C361S106000, C361S115000

Reexamination Certificate

active

06215635

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to electronic devices. More particularly, the present invention relates to thermal management by integrated circuits.
BACKGROUND OF THE INVENTION
Various processes require temperature monitoring for effective control. Such processes obviously include manufacturing processes, but can also include transportation, security, maintenance, and other types of processes during which monitoring the thermal characteristics of devices is necessary or advisable. Today, increasingly, manufacturing processes are automatically controlled; such processes generally require electronic temperature measurement. Further, microcontrollers and processors—common control means in automatic processes—require digital, as opposed to analog, temperature measurements.
Heretofore, the assignee of the present invention has developed thermal management products—primarily temperature sensors—that provide a direct-to-digital output. Because the sensors made by the assignee of the present invention provide a digital reading of temperature directly, any need for an A/D converter dedicated to temperature measurement is eliminated. Assignee's sensors also do not require inherently analog or external discrete components, such as thermistors, for proper operation. Because of the aforementioned characteristics, assignee's sensors can easily be incorporated into integrated circuits.
Notwithstanding the work mentioned above, direct-to-digital temperature sensors still have a number of shortcomings. First and foremost, the costs of manufacturing are high, primarily because the devices must be calibrated—generally trimmed—multiple times. Trimming, in turn, is essential to obtain even reasonable accuracy. Offset voltages and mismatched currents prevent even reasonable accuracy if not addressed by trimming. In many cases, trimming is extremely expensive because a bath is required, which necessitates prepackaging with non-volatile memory.
In view of all of the foregoing, there is a clear need for a direct-to-digital temperature sensor that has reduced manufacturing costs, but high accuracy.
SUMMARY OF THE INVENTION
The present invention meets the aforementioned need by providing a direct-to-digital temperature sensor made up of a single switched-capacitor integrator, with a digital sequencer used to control all required operations.
One advantage of the present invention is the fact that no precise matching is required of any component pairs, because all operations are reduced to a series of samples using the same capacitor.
Another advantage of the present invention is the degree to which accuracy can be easily obtained. This follows from the fact that the only error source in embodiments of the present invention is the offset voltage of the integrator. Since there is just one offset, sophisticated methods can be used to reduce it.
Accordingly, an object of the present invention is to provide an extremely accurate direct-to-digital temperature sensor.
Another object of the present invention is to provide a temperature sensor that can be relatively inexpensively made.


REFERENCES:
patent: 3855466 (1974-12-01), Schwarz
patent: 3999061 (1976-12-01), McLaughlin et al.
patent: 4814692 (1989-03-01), Baumann
patent: 5627316 (1997-05-01), De Winter et al.

Affiliated with

Also associated with

Rating

Direct-to-digital temperature sensor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Direct-to-digital temperature sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct-to-digital temperature sensor will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2552987