JPH0862053A - Selection method of silicon diode for temperature sensor - Google Patents

Abstract

PURPOSE: To increase the yield by ranking silicon diode elements based on the degree of a curve in the temperature/voltage characteristics, combining silicon diode elements having characteristic curves offsetting each other and connecting them in series. CONSTITUTION: A silicon diode element 2 set in a thermostatic bath 1 is fed with a constant current from a constant current source 3 and the output potential is measured by means of a voltmeter 4. Temperature of the thermostatic bath 1 is then varied and the temperature/voltage characteristics of the element 2 are measured. Subsequently, the difference of temperature/voltage characteristics is determined between respective elements 2. A selection graph is determined such that the curve representative of the difference of characteristics intersects the temperature/voltage characteristics of a reference element at two points. The temperature at the middle point between the two point is then set on the selection curve and the voltage difference in the characteristics of the reference element is determined for each element. The elements are ranked according to a decision criteria based on the magnitude and the sign of the voltage difference. Two elements 2 having potential differences offsetting each other are then selected and combined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor constructed by connecting two silicon diode elements in series, and in order to obtain a temperature sensor with little variation in temperature / voltage characteristics, a combination of silicon diode elements is used. Regarding the method of selection.

[0002]

2. Description of the Related Art As a prior art, Japanese Patent Laid-Open No. 1-272323
There is a method disclosed in Japanese Patent No. 0. This method measures the temperature-voltage characteristics of a single silicon diode, calculates the average value, and based on this average value, a standard of the temperature-voltage characteristics obtained when a predetermined number of silicon diodes are connected in series. Calculate the value, set the range of parallel movement tolerance and tilt tolerance with respect to this reference value, add the temperature and voltage characteristics of the measured silicon diode unit by a predetermined number, and add this value to each tolerance. When it is within the range, the combination of the silicon diodes is the one of the temperature sensor.

[0003]

However, in this conventional method, since the selection standard of the temperature / voltage characteristics and the allowable range for the added value are set, the selection standard and the allowable range are set in order to obtain a temperature sensor with less variation. If it is narrowed, the yield will be deteriorated, and conversely, if the selection criteria and the allowable range are widened to increase the yield, the target temperature sensor cannot be obtained. For this reason, it was difficult to unify the quality of the temperature sensor, and the temperature sensor was poor in compatibility.

Therefore, an object of the present invention is to provide a method of selecting a silicon diode for a temperature sensor, which can not only improve the yield but also unify the quality and obtain a highly compatible temperature sensor. is there.

[0005]

The method according to the invention comprises two steps:
In order to configure a temperature sensor by connecting individual silicon diode elements in series, a silicon diode is selected by the following procedure. The process of measuring the temperature and voltage characteristics of each silicon diode element. The process of ranking according to the degree of the temperature / voltage characteristic curve. The process of combining two silicon diode elements of ranks that cancel each other's characteristic curves and connecting them in series.

The present invention can be more specifically selected by the following procedure. The process of measuring the temperature and voltage characteristics of each silicon diode element. The process of obtaining the difference between the temperature and voltage characteristics of the reference element for each silicon diode element. The curve of the difference is the temperature-voltage characteristic curve of the reference element and 2
A process of obtaining a selection graph that intersects at the temperatures Ta and Tb of points. In this selection graph, the temperature Tc at the midpoint between the temperatures Ta and Tb at two points is set, and the temperature of the reference element at this time
A process of obtaining a voltage difference Vx with respect to a voltage characteristic for each silicon diode element and ranking the difference according to the magnitude and positive / negative. A process in which two silicon diode elements of ranks that cancel each other's voltage difference Vx are combined and connected in series.

[0007]

According to the present invention, attention is paid to the temperature / voltage characteristic curve of the silicon diode element, and the two characteristic values are divided into ranks according to the degree of the characteristic curve, and the two silicon diode elements having ranks that cancel each other out. Therefore, the two silicon diode elements absorb each other's characteristic variations.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described in detail with reference to the drawings.

First, the temperature of each silicon diode element
In order to examine the voltage characteristics, a silicon diode element (hereinafter referred to as an element) 2 is placed in a thermostatic chamber 1 as shown in FIG. 1, and a constant current is applied to the element 2 by a constant current source 3 so that the element 2
The output potential of is measured with a voltmeter 4. Then, the temperature inside the constant temperature bath 1 is changed, and the temperature / voltage characteristics of the element 2 are measured as shown in FIG.

Next, the temperature of the reference element
The difference of each element 2 with respect to the voltage characteristic (shown in FIG. 3) is obtained as shown in FIG. Further, by calculation, the curve of the difference is the temperature / voltage characteristic curve of the reference element and the two temperatures Ta / Tb.
4 is modified so as to intersect with each other, and a selection graph as shown in FIG. 5 is obtained.

Next, in this selection graph, the temperature Tc at the midpoint between the two temperatures Ta and Tb is set, and the voltage difference Vx with respect to the temperature / voltage characteristic of the reference element at this time is obtained for each element 2. According to the criterion, the rank is divided according to the magnitude and positive / negative, as shown in FIG. According to this rank division, two elements 2 having ranks that cancel each other's voltage difference Vx are selected and combined. For example, in FIG. 6, H1 and L1, H2 and L2, and H3 and L3 are combined. Then, as shown in FIG. 7, the two elements 2H and 2L whose combination is determined are connected to the case 5 as shown in FIG.
A temperature sensor is formed by connecting in series inside and drawing both ends out of the case 5 as output terminals 6 and 7.

[0012]

According to the present invention, since the silicon diode elements are ranked according to the degree of the temperature / voltage characteristic curve, and two silicon diode elements of different ranks that cancel each other characteristic curves are combined, The two silicon diode elements absorb each other's characteristic variation. Therefore, not only the yield is increased, but also the quality is unified, and the temperature sensor having excellent compatibility can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a measuring method for measuring a temperature / voltage characteristic of a silicon diode element in a method according to the present invention.

FIG. 2 is a graph of measured temperature / voltage characteristics of a silicon diode element.

FIG. 3 is a temperature / voltage characteristic graph of a reference element.

FIG. 4 is a graph showing a difference in temperature / voltage characteristics of a reference element.

FIG. 5 is a selection graph obtained by modifying FIG. 4 so that the difference curve of FIG. 4 intersects the temperature-voltage characteristic curve of the reference element at two temperatures.

FIG. 6 is a ranking diagram in which silicon diode elements are ranked according to a selection graph.

FIG. 7 is a schematic diagram of a temperature sensor in which two silicon diode elements are selected and combined from ranks.

[Explanation of symbols]

2 Silicon diode elements 2H and 2L combined silicon diode elements

Claims (2)

[Claims] 1. A temperature sensor comprising two silicon diode elements connected in series, wherein the temperature and voltage characteristics of each silicon diode element are measured and ranked according to the degree of the temperature / voltage characteristic curve. A method of selecting a silicon diode for a temperature sensor, which comprises a step and a step of connecting two silicon diode elements of ranks that cancel each other's characteristic curves and connecting them in series. 2. In a temperature sensor constituted by connecting two silicon diode elements in series, a process of measuring temperature / voltage characteristics of each silicon diode element and temperature / voltage characteristics of a reference element for each silicon diode element. And a step of obtaining a selection graph such that the curve of the difference intersects the temperature-voltage characteristic curve of the reference element at the temperatures Ta and Tb of two points, and the temperature Ta of the two points in this selection graph. The process of setting the temperature Tc at the midpoint between Tb, obtaining the voltage difference Vx with respect to the temperature / voltage characteristic of the reference element at this time for each silicon diode element, and classifying the voltage according to its magnitude and positive / negative, and each voltage The temperature sensor is composed of two silicon diode elements of different ranks that cancel each other out of the difference Vx and are connected in series. How to select silicon diode for service.