JPH0617832B2 - Electronic thermometer - Google Patents
Electronic thermometerInfo
- Publication number
- JPH0617832B2 JPH0617832B2 JP58149552A JP14955283A JPH0617832B2 JP H0617832 B2 JPH0617832 B2 JP H0617832B2 JP 58149552 A JP58149552 A JP 58149552A JP 14955283 A JP14955283 A JP 14955283A JP H0617832 B2 JPH0617832 B2 JP H0617832B2
- Authority
- JP
- Japan
- Prior art keywords
- resistance
- circuit
- body temperature
- battery
- oscillating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/32—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using change of resonant frequency of a crystal
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K13/00—Thermometers specially adapted for specific purposes
- G01K13/20—Clinical contact thermometers for use with humans or animals
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Measuring And Recording Apparatus For Diagnosis (AREA)
Description
【発明の詳細な説明】 〔発明の技術分野〕 この発明は電子体温計に関する。Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an electronic thermometer.
電子体温計ＬＳＩの電源としては電池を使用するのが一
般的である。しかし電池電圧が下がると、温度測定に大
きな誤差が生ずる。従つて従来の電子体温計では電池電
圧を監視し一定電圧以下になると警告を発するよう構成
されている。電池の電圧降下をか監視する為の従来一般
に使用されている方法は、ＦＥＴのドレインとソース間
の電圧降下によつて、ドレインとソース間の抵抗が大き
くなることを利用している。このＦＥＴの特性を利用し
た電池切れ回路は電源とグランドの間に抵抗ＦＥＴを直
列に結合し、電源電圧を分割するよう構成されている。
電池切れにより電源電圧が降下するＦＥＴ抵抗が増加
し、分割電圧が上昇し、次段に設けられたゲートの閾値
をこえる。このゲートの変化によつて電池切れの警告を
発してしる。しかしながらこの回路を使用しした場合、
ＦＥＴ抵抗がばらつく為、ＬＳＩ内にあるＦＥＴの抵抗
に適合した直列抵抗を外部から加える必要が生ずる。す
なわちＬＳＩ化することによつて部品数が減少したにも
かかわらず、電池切れ検出用に外部部品が増加し、しか
もＬＳＩ毎にＦＥＴ特性を測定し適合した抵抗をさがす
手間も必要となる。またＦＥＴ特性のばらつきが仕様範
囲外にある時はＩＣの本質的な機能でない電池切れ検出
回路によつて、不良ＩＣが続出しＩＣのコストを上げて
しまう。A battery is generally used as a power source of the electronic thermometer LSI. However, when the battery voltage drops, a large error occurs in the temperature measurement. Therefore, the conventional electronic thermometer is configured to monitor the battery voltage and issue a warning when the voltage drops below a certain level. A commonly used method for monitoring the voltage drop of a battery utilizes the fact that the resistance between the drain and the source increases due to the voltage drop between the drain and the source of the FET. The dead battery circuit utilizing the characteristics of the FET is configured to divide the power supply voltage by connecting a resistance FET in series between the power supply and the ground.
When the battery runs out, the power supply voltage drops, the FET resistance increases, and the division voltage rises, exceeding the threshold value of the gate provided in the next stage. This change in the gate gives a warning that the battery is dead. However, when using this circuit,
Since the FET resistance varies, it is necessary to add a series resistance suitable for the resistance of the FET in the LSI from the outside. That is, although the number of parts has decreased due to the use of LSI, the number of external parts for battery dead detection increases, and it is necessary to measure the FET characteristics of each LSI and find a suitable resistance. Further, when the variation of the FET characteristics is out of the specification range, the dead battery detection circuit, which is not an essential function of the IC, causes the defective IC to continue and increase the cost of the IC.
この発明は上述した従来の問題点を改良したもので、電
子体温計ＬＳＩの外部に電源電圧監視用回路の設けずに
電源の電圧降下を監視する電子体温計を提供することを
目的とする。The present invention is to improve the above-mentioned conventional problems, and an object thereof is to provide an electronic clinical thermometer for monitoring a voltage drop of a power supply without providing a power supply voltage monitoring circuit outside the electronic thermometer LSI.
この発明は温度によつて抵抗が変化するサーミスタＣＲ
発振器に組み込み、抵抗が変化することによる発振周波
数の変化を読み取り温度計測を行う電子体温計であつ
て、特に温度変化と関係のない発振周波数の変化を取り
除くためにＣＲ発振器の抵抗として温度によつて変化し
ない基準抵抗とサーミスタを交互に使用し、使用する抵
抗の違いによる発振周波数の比較を行うようにした電子
体温計において、基準抵抗によつて発振している時の発
振周波数が電源電圧の降下、特に一定電圧以下に降下し
たときに、急激に変化することを利用し、その時の発振
周波数の変化を検出することにより電源・電圧降下を検
出することを可能としたものである。This invention is a thermistor CR whose resistance changes with temperature.
An electronic thermometer that incorporates in an oscillator and reads the change in oscillation frequency due to changes in resistance to measure temperature.In particular, in order to eliminate changes in oscillation frequency that are unrelated to temperature changes, the temperature of CR oscillator is In an electronic thermometer that alternately uses a reference resistance and a thermistor that do not change, and compares the oscillation frequency according to the difference in the resistance used, the oscillation frequency when oscillating by the reference resistance is the drop in the power supply voltage, In particular, it is possible to detect the power supply / voltage drop by detecting the change in the oscillation frequency at that time by utilizing the rapid change when the voltage drops below a certain voltage.
本発明は体温測定に本来必要な機能を電源電圧の監視に
使用している為、新たに体温計用ＬＳＩの外部に部品を
取りつける必要がない。従つて電源電圧の監視の為に部
品が増加したり回路が複雑になつたりしない。Since the present invention uses the function originally required for body temperature measurement to monitor the power supply voltage, it is not necessary to newly install a part outside the thermometer LSI. Therefore, the number of parts and the circuit are not complicated due to the monitoring of the power supply voltage.
以下この発明を図面の参照して詳細に説明する。 The present invention will be described below in detail with reference to the drawings.
第１図はこの発明に使用されている体温測定用発振器を
示している。この発振器は直列に接続されたインバータ
１−ａ，１−ｂと、インバータ１−ａの入力流とインバ
ータ１−ｂの出力端間に設けられたコンデンサ４と、一
端がそれぞれインバータ１−ａの入力端に接続され他端
がスイツチ２によつて選択的にインバータ１−ａの出力
端に接続されるサーミスタ抵抗３および基準抵抗５とか
らなるＣＲ発振器である。この発振器はスイツチ２によ
つて抵抗３，５が交互に切り換えられる。サーミスタ抵
抗Rx３が回路に接続された時の発振周波数fxはコンデン
サ４の値をＣとすると となり、この発振周波数fxが体温を示している。基準抵
抗Rs５がスイツチ２によつて回路に接続された時の発振
周波数fsは となり、この発振周波数は前述した電源電圧の変動やコ
ンデンサ４の経時変化を補正する為に使用する。基準発
振周波数fsはイバータ１−ａ，１−ｂに印加される電源
電圧VDが一定電圧以下に下がると第２図に示すように急
激に減少する。すなわち発振周波数fsを監視していれば
電源電圧VDが一定値以下になつたことを発見できる。FIG. 1 shows a body temperature measuring oscillator used in the present invention. This oscillator has inverters 1-a and 1-b connected in series, a capacitor 4 provided between an input flow of the inverter 1-a and an output terminal of the inverter 1-b, and one end of the inverter 1-a. The CR oscillator is composed of a thermistor resistor 3 and a reference resistor 5 which are connected to the input end and the other end of which is selectively connected to the output end of the inverter 1-a by the switch 2. In this oscillator, the switch 3 alternately switches the resistors 3 and 5. The oscillation frequency fx when the thermistor resistance Rx3 is connected to the circuit is C when the value of the capacitor 4 is And this oscillation frequency fx shows the body temperature. The oscillation frequency fs when the reference resistance Rs5 is connected to the circuit by the switch 2 is This oscillating frequency is used to correct the above-mentioned fluctuations in the power supply voltage and aging of the capacitor 4. The reference oscillation frequency fs sharply decreases as shown in FIG. 2 when the power supply voltage V D applied to the inverters 1-a and 1-b falls below a certain voltage. That is, if the oscillation frequency fs is monitored, it can be found that the power supply voltage V D has dropped below a certain value.
第３図に体温測定用ＬＩＳ６のブロツク図を示す。この
ブロツク中の体温測定用発振回路７の中に第１図に示さ
れたインバータ１−ａ，インバータ１−ｂとスイツチ２
が含まれている。スイツチ２はCMOS LSI内に含まれてい
る為ＭＯＳの電子スイツチであり、体温測定回路８によ
つて切り換え制御が行なわれる。体温測定回路８は発振
周波数fs，fxを測定し、体温に変換しＬＣＤ端子９に出
力する。体温測定回路８は体温測定発振回路７の発振パ
ルスを一定時間計数することによつて発振周波数を測定
している。この一定時間を得る為水晶振動子１０を用い
た水晶発振器１１の出力パルスが体温測定回路８に入力
される。次に電源電圧を監視し、電池切れを検出する電
池切れ検出回路１２について説明する。この電池切れ検
出回路１２は体温測定回路８と同様に発振周波数を測定
することによつて電池切れを検出している。すなわち第
２図の説明で述べたように発振周波数fsを測定してい
る。この機能は体温測定発振回路７が発振周波数fsで発
振している時の出力パルスを一定時間計数することによ
つて達成されている。電池切れ検出回路１２は前述の機
能を果す為、時間計測用の水晶発振器１１の出力パルス
を得る。また現在体温測定発振回路７が発振周波数fsで
発振していることを知る為、電池切れ検出回路１２は体
温測定回路８の電子スイツチ切り換え制御信号を得る。
電池切れが発見されるとＬＣＤ出力端子１３に電池切れ
信号が出力される。第４図に電池切れ検出回路１２のブ
ロツク図を示す。体温測定回路８からの電子スイツチ切
り換え制御信号が端子１４に入力される。この信号はモ
ノマルチバイブレータ１５に入力される。フリツプフロ
ツプ１６はモノマルチバイブレータ１５の出力パルスに
よつてセツトされ、フリツプフロツプ１６の出力はゲー
ト１７に入力される。すなわちゲート１７は体温測定用
発振回路７が発振周波数fsで発振していることを知る。
体温測定用発振回路７からの入力端子１８より入力され
た発振パルスはフリツプフロツプ１６がセツトされてい
る時ゲート１７を通りカウンタ１９に入力される。カウ
ンタ１９は発振周波数を計測する為カウンタアツプす
る。ゲート２０は電子スイツチ切り換え信号によつて、
体温測定発振回路７が発振周波数fsで発振していること
を知り、端子２１に入力される水晶発振器１１からの出
力パルスをカウンタ２２に入力する。デコーダ２３はカ
ウンタ２２の内容を監視し一定時間になつた時フリツプ
フロツプ１６をリセツトし、ゲート１７を閉じる。この
ようにしてカウンタ１９は一定時間だけ体温測定発振回
路７の出力パルスを計数することにより発振周波数を測
定する。比較器２４は電池切れ時のカウンタ１９の値を
発生する定数発生回路２５の内容とカウンタ１９のカウ
ント結果を比較し、電池切れならばＬＣＤ出力端子１３
に電池切れ信号を出力する。FIG. 3 shows a block diagram of LIS6 for measuring body temperature. In the body temperature measuring oscillation circuit 7 in this block, the inverter 1-a, the inverter 1-b and the switch 2 shown in FIG.
It is included. The switch 2 is a MOS electronic switch because it is included in the CMOS LSI, and its switching control is performed by the body temperature measuring circuit 8. The body temperature measuring circuit 8 measures the oscillation frequencies fs and fx, converts them into body temperature, and outputs them to the LCD terminal 9. The body temperature measuring circuit 8 measures the oscillation frequency by counting the oscillation pulses of the body temperature measuring and oscillating circuit 7 for a certain period of time. In order to obtain this fixed time, the output pulse of the crystal oscillator 11 using the crystal oscillator 10 is input to the body temperature measuring circuit 8. Next, the battery dead detection circuit 12 that monitors the power supply voltage and detects the battery dead will be described. The battery dead detection circuit 12 detects the battery dead by measuring the oscillation frequency like the body temperature measurement circuit 8. That is, the oscillation frequency fs is measured as described in the explanation of FIG. This function is achieved by counting the output pulses for a certain period of time when the body temperature measurement oscillation circuit 7 is oscillating at the oscillation frequency fs. Since the dead battery detection circuit 12 performs the above-mentioned function, it obtains the output pulse of the crystal oscillator 11 for time measurement. Further, in order to know that the body temperature measuring / oscillating circuit 7 is currently oscillating at the oscillation frequency fs, the dead battery detecting circuit 12 obtains the electronic switch switching control signal of the body temperature measuring circuit 8.
When the battery is found dead, a battery dead signal is output to the LCD output terminal 13. FIG. 4 shows a block diagram of the battery dead detection circuit 12. An electronic switch switching control signal from the body temperature measuring circuit 8 is input to the terminal 14. This signal is input to the mono multivibrator 15. The flip-flop 16 is set by the output pulse of the mono-multivibrator 15, and the output of the flip-flop 16 is input to the gate 17. That is, the gate 17 knows that the body temperature measuring oscillation circuit 7 is oscillating at the oscillation frequency fs.
The oscillation pulse input from the input terminal 18 from the body temperature measuring oscillation circuit 7 is input to the counter 19 through the gate 17 when the flip-flop 16 is set. The counter 19 counts up to measure the oscillation frequency. The gate 20 receives an electronic switch switching signal,
Knowing that the body temperature measurement oscillation circuit 7 is oscillating at the oscillation frequency fs, the output pulse from the crystal oscillator 11 input to the terminal 21 is input to the counter 22. The decoder 23 monitors the contents of the counter 22 and resets the flip-flop 16 and closes the gate 17 when a fixed time elapses. In this way, the counter 19 measures the oscillation frequency by counting the output pulses of the body temperature measuring and oscillating circuit 7 for a fixed time. The comparator 24 compares the content of the constant generation circuit 25 that generates the value of the counter 19 when the battery is dead with the count result of the counter 19, and if the battery is dead, the LCD output terminal 13
Outputs the battery dead signal to.
〔発明の他の実施例〕 本実施例では一定時間パルスを計数する方法を用いて周
波数測定を行つているが、必ずしもこの方法を用いる必
要はなく、たとえばパルスをコンデンサや積分回路に入
力し、その電圧値を読み取ることによつて電池切れを検
出してもよい。[Other Embodiments of the Invention] In this embodiment, frequency measurement is performed using a method of counting pulses for a certain period of time, but it is not always necessary to use this method, for example, by inputting pulses to a capacitor or an integrating circuit, The dead battery may be detected by reading the voltage value.
第１図は体温測定用発振器、第２図は電源電圧に対する
発振周波数のグラフ、第３図は体温測定用ＬＳＩのブロ
ツク図、第４図は電池切れ検出回路のブロツク図であ
る。 ３……サーミスタ抵抗、４……コンデンサ ５……基準抵抗、６……体温測定用ＬＳＩ ７……体温測定発振回路、８……体温測定回路 １１……水晶発振器、１２……電池切れ検出回路FIG. 1 is a body temperature measuring oscillator, FIG. 2 is a graph of oscillation frequency against power supply voltage, FIG. 3 is a block diagram of a body temperature measuring LSI, and FIG. 4 is a block diagram of a dead battery detection circuit. 3 ... Thermistor resistance, 4 ... Capacitor 5 ... Reference resistance, 6 ... Body temperature measurement LSI 7 ... Body temperature measurement oscillator circuit, 8 ... Body temperature measurement circuit 11 ... Crystal oscillator, 12 ... Battery exhaustion detection circuit
Claims (1)
タ抵抗と、 温度によって抵抗値が変化しない基準抵抗と、 前記サーミスタ抵抗と前記基準抵抗を所定時間間隔で選
択的に切り換える切換部と、 この切換部によって切り換えられた前記サーミスタ抵抗
と前記基準抵抗が交互に接続されて発振する発振回路
と、 前記発振回路が前記基準抵抗と前記サーミスタ抵抗に交
互に切り換えられて発振している時のそれぞれの発振周
波数を比較して体温を測定する体温測定部と、 この体温測定部が体温を測定している時の前記基準抵抗
に切り換えられて発振している前記発振回路の発振周波
数に基づいて電池切れを検出する電池切れ検出回路を備
えたことを特徴とする電子体温計。1. A thermistor resistance when a resistance value changes with temperature, a reference resistance whose resistance value does not change with temperature, a switching section which selectively switches the thermistor resistance and the reference resistance at a predetermined time interval, and this switching section. An oscillation circuit in which the thermistor resistance and the reference resistance that are switched by are alternately connected to oscillate, and respective oscillation frequencies when the oscillation circuit is alternately switched to the reference resistance and the thermistor resistance and oscillates The battery temperature is detected based on the oscillating frequency of the oscillating circuit that is oscillating by switching to the reference resistance when the body temperature measuring unit measures the body temperature. An electronic thermometer, which is equipped with a battery exhaustion detection circuit that operates.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58149552A JPH0617832B2 (en) | 1983-08-18 | 1983-08-18 | Electronic thermometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58149552A JPH0617832B2 (en) | 1983-08-18 | 1983-08-18 | Electronic thermometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6042622A JPS6042622A (en) | 1985-03-06 |
| JPH0617832B2 true JPH0617832B2 (en) | 1994-03-09 |
Family
ID=15477653
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58149552A Expired - Lifetime JPH0617832B2 (en) | 1983-08-18 | 1983-08-18 | Electronic thermometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0617832B2 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4321933A (en) * | 1979-08-23 | 1982-03-30 | Baessler Medical Electronics, Inc. | Telemetry system for monitoring hospital patient temperature |
| JPS5873831A (en) * | 1981-10-27 | 1983-05-04 | Omron Tateisi Electronics Co | Electronic thermometer |
| JPS6021428A (en) * | 1983-07-15 | 1985-02-02 | Kyushu Hitachi Maxell Ltd | Electronic clinical thermometer |
-
1983
- 1983-08-18 JP JP58149552A patent/JPH0617832B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6042622A (en) | 1985-03-06 |
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