Temperature characteristic correction method and sensor amplification circuit

Abstract

A temperature characteristic correction method enabling easy setting of correction points, while reducing deviations of an output signal from a target value and preventing power supply noise and power consumption from increasing. The method includes storing correction patterns, each of which includes correction points set at a temperature interval that differs between the correction patterns. The method further includes storing correction data for each correction point in each correction pattern, selecting a correction pattern corresponding to the temperature dependent characteristic of the input signal from the correction patterns, and correcting the temperature dependent characteristic of the input signal with the selected correction pattern and the correction data corresponding to the selected correction pattern.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

FIG. 1 is a schematic circuit diagram showing a sensor amplification circuit in the prior art;

FIG. 2 is a graph showing a correction operation for correcting a temperature dependent characteristic performed by the prior art sensor amplification circuit;

FIG. 3 is a schematic circuit diagram showing a sensor amplification circuit in the prior art;

FIGS. 4( a) to 4(e) are graphs showing various temperature dependent characteristics;

FIG. 5 is a graph showing a correction operation for correcting a temperature dependent characteristic performed by a sensor amplification circuit in the prior art;

FIG. 6 is a schematic circuit diagram showing a sensor amplification circuit according to a first embodiment of the present invention;

FIG. 7 is a schematic block diagram showing a control unit of the sensor amplification circuit in the first embodiment;

FIG. 8 is a table showing a correction pattern map;

FIG. 9 is a table showing a correction pattern map;

FIG. 10 is a graph showing a correction pattern in the first embodiment;

FIG. 11 is a graph showing another correction pattern in the first embodiment;

FIG. 12 is a graph showing a further correction pattern in the first embodiment;

FIG. 13 is a graph showing a correction operation of the sensor amplification circuit in the first embodiment;

FIG. 14 is a graph showing a correction pattern according to a second embodiment of the present invention; and

FIG. 15 is a graph showing a correction pattern according to a third embodiment of the present invention.

Claims

1. A method for correcting a temperature dependent characteristic of an input signal, the method comprising: storing a plurality of correction patterns, each including a plurality of correction points set at a temperature interval that differs between the correction patterns;storing correction data for each of the correction points in each of the correction patterns;selecting a correction pattern corresponding to the temperature dependent characteristic of the input signal from the plurality of correction patterns; andcorrecting the temperature dependent characteristic of the input signal with the selected correction pattern and the correction data corresponding to the selected correction pattern.

2. The method according to claim 1, wherein the temperature interval of the correction points in each of the correction patterns is set in accordance with a gradient of the temperature dependent characteristic of the input signal.

3. The method according to claim 1, wherein each of the correction patterns includes gradient data for correcting the temperature dependent characteristic between the correction points.

4. The method according to claim 3, wherein the gradient data includes a gradient of a temperature dependent characteristic corresponding to the temperature interval of the correction points.

5. The method according to claim 1, further comprising: adjusting the temperature interval of the correction points in each of the correction patterns to generate a new correction pattern.

6. The method according to claim 1, further comprising: shifting the temperature of each of the correction points in each of the correction patterns to generate a new correction pattern.

7. An amplification circuit for a sensor, the amplification circuit comprising: a memory device for storing a plurality of correction patterns set in accordance with various temperature dependent characteristics of an input signal, wherein each of the correction pattern includes a plurality of correction points set at a temperature interval that differs between the correction patterns, and the memory device further stores correction data for each of the correction points;a correction circuit for correcting the temperature dependent characteristic of the input signal with the correction data for each of the correction points in the correction patterns;a temperature sensor for detecting ambient temperature; anda control circuit for operating the correction circuit based on the correction pattern and the correction data corresponding to the ambient temperature detected by the temperature sensor.

8. The amplification circuit according to claim 7, wherein the temperature interval for each of the correction patterns stored in the memory device is set in accordance with a gradient of the temperature dependent characteristic of the input signal.

9. The amplification circuit according to claim 7, wherein each of the correction patterns stored in the memory device includes gradient data for correcting the temperature dependent characteristic between the correction points.

10. The amplification circuit according to claim 9, wherein the gradient data includes a gradient of the temperature dependent characteristic corresponding to the temperature interval of the correction points.