JP3454708B2 - Current detector - Google Patents
Current detectorInfo
- Publication number
- JP3454708B2 JP3454708B2 JP09356998A JP9356998A JP3454708B2 JP 3454708 B2 JP3454708 B2 JP 3454708B2 JP 09356998 A JP09356998 A JP 09356998A JP 9356998 A JP9356998 A JP 9356998A JP 3454708 B2 JP3454708 B2 JP 3454708B2
- Authority
- JP
- Japan
- Prior art keywords
- reference voltage
- voltage
- current
- value
- voltage signal
- Prior art date
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- Expired - Fee Related
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- Amplifiers (AREA)
- Measurement Of Current Or Voltage (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、直流電源に負荷を
接続して構成される負荷回路に流れる電流値を、負荷回
路に直列に挿入接続されたシャント抵抗の端子間電圧差
から検出する如く構成された電流検出装置に係り、特
に、差動増幅回路の温度変化に起因する検出誤差を除去
して、高精度の電流検出値を得ることができる電流検出
装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to detect a current value flowing in a load circuit configured by connecting a load to a DC power source from a voltage difference between terminals of a shunt resistor inserted in series and connected to the load circuit. The present invention relates to a configured current detection device, and more particularly to a current detection device capable of obtaining a highly accurate current detection value by removing a detection error caused by a temperature change of a differential amplifier circuit.
【０００２】[0002]
【従来の技術】従来より、直流電源に負荷を接続して構
成される負荷回路に流れる電流値を、負荷回路に直列に
挿入接続されたシャント抵抗の端子間電圧差から検出す
る如く構成された電流検出装置が一般に知られている。2. Description of the Related Art Conventionally, a current value flowing in a load circuit formed by connecting a load to a DC power supply is configured to be detected from a voltage difference between terminals of a shunt resistor inserted and connected in series to the load circuit. Current sensing devices are generally known.
【０００３】ここで、従来の電流検出装置について、図
５を参照して説明すると、電流検出装置１０１は、所定
電圧Ｖb の供給源となる直流電源１０３に負荷１０５を
接続して構成される負荷回路１０２に直列に挿入接続さ
れ、既知の低抵抗値Ｒs を呈するシャント抵抗１０７
と、シャント抵抗１０７における両端子の電圧をそれぞ
れ入力するとともに、端子間電圧差を増幅してアナログ
形態の差分電圧信号として出力する差動増幅回路１０９
と、差動増幅回路１０９から入力したアナログ形態の差
分電圧信号ＶDFを、ディジタル形態の差分電圧信号に変
換して出力するＡ／Ｄ変換回路１１１と、Ａ／Ｄ変換回
路１１１から入力したディジタル形態の差分電圧信号
と、シャント抵抗１０７の抵抗値Ｒs とを参照して、負
荷回路１０２に流れる電流値Ｉb を演算し、この演算に
より得られた電流値Ｉb を、電流計１１５に表示させる
ＥＣＵ１１３と、を備えて構成される。A conventional current detecting device will now be described with reference to FIG. 5. The current detecting device 101 is a load constructed by connecting a load 105 to a DC power source 103 which is a supply source of a predetermined voltage Vb. A shunt resistor 107 that is inserted and connected in series with the circuit 102 and exhibits a known low resistance value Rs.
And a differential amplifier circuit 109 for inputting voltages of both terminals of the shunt resistor 107 and amplifying a voltage difference between the terminals to output as an analog difference voltage signal.
And an A / D conversion circuit 111 for converting the analog differential voltage signal V DF input from the differential amplifier circuit 109 into a digital differential voltage signal and outputting the digital differential voltage signal, and a digital input from the A / D conversion circuit 111. The ECU 113 for calculating the current value Ib flowing through the load circuit 102 with reference to the differential voltage signal of the form and the resistance value Rs of the shunt resistor 107 and displaying the current value Ib obtained by this calculation on the ammeter 115. And are configured.
【０００４】上述した電流検出装置１０１によれば、ま
ず、差動増幅回路１０９は、シャント抵抗１０７におけ
る両端子の電圧をそれぞれ入力する一方、端子間電圧差
を増幅してアナログ形態の差分電圧信号として出力す
る。Ａ／Ｄ変換回路１１１は、差動増幅回路１０９から
入力したアナログ形態の差分電圧信号ＶDFを、ディジタ
ル形態の差分電圧信号に変換して出力する。そして、Ｅ
ＣＵ１１３は、Ａ／Ｄ変換回路１１１から入力したディ
ジタル形態の差分電圧信号と、シャント抵抗１０７の抵
抗値Ｒs とを参照して、負荷回路１０２に流れる電流値
Ｉb を演算し、この演算により得られた電流値Ｉb を電
流計１１５に表示させる。According to the above-described current detecting device 101, first, the differential amplifier circuit 109 inputs the voltages of both terminals of the shunt resistor 107, respectively, and amplifies the voltage difference between the terminals to generate an analog differential voltage signal. Output as. The A / D conversion circuit 111 converts the analog differential voltage signal V DF input from the differential amplifier circuit 109 into a digital differential voltage signal and outputs it. And E
The CU 113 calculates the current value Ib flowing through the load circuit 102 with reference to the digital differential voltage signal input from the A / D conversion circuit 111 and the resistance value Rs of the shunt resistor 107, and obtains this value by this calculation. The current value Ib is displayed on the ammeter 115.
【０００５】したがって、電流計１１５の指示値を読む
ことにより、負荷回路１０２に流れる電流値Ｉb を知る
ことができる。Therefore, the current value Ib flowing through the load circuit 102 can be known by reading the indication value of the ammeter 115.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上述し
た従来の電流検出装置１０１にあっては、アナログレベ
ルの信号処理を行う差動増幅回路１０９の信号入出力特
性が温度依存性を有することに起因する電流検出誤差を
生じるという解決すべき課題があった。However, in the above-described conventional current detecting device 101, the signal input / output characteristic of the differential amplifier circuit 109 which performs analog level signal processing has temperature dependency. However, there is a problem to be solved that a current detection error occurs.
【０００７】これについて述べると、差動増幅回路１０
９において、シャント抵抗１０７における両端子の電圧
をそれぞれ入力する一方、端子間電圧差を増幅して差分
電圧信号ＶDFとして出力する場合を考察すれば、差動増
幅回路１０９の増幅倍率、いわゆるゲインが温度依存性
を有すること、及び差動増幅回路１０９中に含まれる抵
抗成分値が温度依存性を有すること等に起因して、例え
ば図６（ａ），（ｂ）に示すように、差動増幅回路１０
９に温度変化が生じたときの、電流値Ｉb の変動に対す
る差分電圧信号ＶDFの変化特性は、傾き及び切片が温度
変化に追従して変動することとなり、結果として、得ら
れた電流値Ｉb が誤差を含むものとなる。To describe this, the differential amplifier circuit 10
In FIG. 9, considering the case where the voltages of both terminals of the shunt resistor 107 are respectively input and the voltage difference between the terminals is amplified and output as the differential voltage signal V DF , the amplification factor of the differential amplifier circuit 109, the so-called gain. Has a temperature dependency, and the resistance component value included in the differential amplifier circuit 109 has a temperature dependency, for example, as shown in FIGS. 6A and 6B. Dynamic amplifier circuit 10
In the change characteristic of the differential voltage signal V DF with respect to the change of the current value Ib when the temperature change occurs in 9, the slope and the intercept change according to the temperature change, and as a result, the obtained current value Ib is obtained. Will include an error.
【０００８】この電流検出誤差を除去するには、例え
ば、差動増幅回路１０９の近傍に、差動増幅回路１０９
の温度を検出する温度センサを設けておくとともに、温
度センサで検出された差動増幅回路１０９の温度データ
にそれぞれ対応付けられた温度補正テーブルをあらかじ
めＥＣＵ１１３に記憶させておき、温度センサで検出さ
れた差動増幅回路１０９の温度データと、温度補正テー
ブルとを参照して、ＥＣＵ１１３での演算により得られ
た電流値Ｉb から温度依存成分を除去する補正を行うこ
とが考えられる。In order to remove this current detection error, for example, the differential amplifier circuit 109 is provided near the differential amplifier circuit 109.
A temperature sensor for detecting the temperature is provided, and a temperature correction table associated with the temperature data of the differential amplifier circuit 109 detected by the temperature sensor is stored in the ECU 113 in advance and detected by the temperature sensor. It is conceivable that the temperature data of the differential amplifier circuit 109 and the temperature correction table are referred to perform correction for removing the temperature dependent component from the current value Ib obtained by the calculation in the ECU 113.
【０００９】ところが、上述した電流検出誤差の除去手
法によれば、温度センサの追加を要するために、装置構
成が複雑化するという新たな課題を生じることになる。However, according to the method for removing the current detection error described above, a new problem arises in that the device configuration becomes complicated because it requires the addition of a temperature sensor.
【００１０】そこで、このような現状の下で、差動増幅
回路に温度変化が生じた場合であっても、簡素な装置構
成をもって、差動増幅回路の温度変化に起因する検出誤
差を除去して、高精度の電流検出値を得ることができる
新規な電流検出装置の開発が関係者の間で待望されてい
た。Under these circumstances, therefore, even if the differential amplifier circuit changes in temperature, the detection error caused by the temperature change in the differential amplifier circuit can be removed with a simple device configuration. Therefore, the development of a new current detection device capable of obtaining a highly accurate current detection value has been long awaited by the parties concerned.
【００１１】本発明は、上記した実情を鑑みてなされた
ものであり、Ａ／Ｄ変換回路からシャント抵抗の端子間
電圧差を表す差分電圧値が入力されたとき、入力された
差分電圧値に内包されている、差動増幅回路の温度変化
に起因する検出誤差を、複数の参照電圧値の組み合わせ
変数に関連付けて記憶された補正情報のうち、参照電圧
記憶手段に更新記憶されている複数の参照電圧値の組み
合わせに係る補正情報を用いて補正することにより、差
動増幅回路に温度変化が生じた場合であっても、簡素な
装置構成をもって、差動増幅回路の温度変化に起因する
検出誤差を除去して、高精度の電流検出値を得ることが
できる電流検出装置を提供することを課題とする。The present invention has been made in view of the above situation, and when a differential voltage value representing the voltage difference between terminals of a shunt resistor is input from the A / D conversion circuit, the input differential voltage value is Among the correction information stored in association with the detection error caused by the temperature change of the differential amplifier circuit associated with the combination variables of the plurality of reference voltage values, a plurality of pieces of update information stored in the reference voltage storage means are stored. By performing correction using the correction information related to the combination of the reference voltage values, even if the temperature of the differential amplifier circuit changes, the detection due to the temperature change of the differential amplifier circuit can be performed with a simple device configuration. An object of the present invention is to provide a current detection device that can obtain an accurate current detection value by removing an error.
【００１２】[0012]
【課題を解決するための手段】上記課題を解決するため
に、請求項１の発明は、直流電源に負荷を接続して構成
される負荷回路に流れる電流値を、当該負荷回路に直列
に挿入接続されたシャント抵抗の端子間電圧差から検出
する如く構成された電流検出装置であって、前記シャン
ト抵抗の端子間電圧差を増幅してアナログ形態の差分電
圧信号として出力する検出電圧差増幅手段と、相互に値
が異なる複数の参照電圧をそれぞれ増幅してアナログ形
態の参照電圧信号として各々出力する複数の参照電圧増
幅手段と、前記検出電圧差増幅手段から出力される差分
電圧信号と、前記複数の参照電圧増幅手段から各々出力
される複数の参照電圧信号とのうち、いずれか１つの電
圧信号を予め決められている優先度に基づいて順次選択
出力する電圧信号選択手段と、を含んで構成される差動
増幅回路と、当該差動増幅回路から入力したアナログ形
態の電圧信号を、ディジタル形態の電圧信号に変換して
出力するＡ／Ｄ変換回路と、当該Ａ／Ｄ変換回路から入
力した電圧信号のうち、複数の参照電圧値をそれぞれ更
新記憶する参照電圧記憶手段と、前記複数の参照電圧値
の組み合わせ変数に関連付けて、前記差動増幅回路の温
度変化に起因する検出誤差を補正する際に用いられる補
正情報を記憶する補正情報記憶手段と、前記Ａ／Ｄ変換
回路から前記シャント抵抗の端子間電圧差を表す差分電
圧値が入力されたとき、当該入力された差分電圧値に内
包されている、前記差動増幅回路の温度変化に起因する
検出誤差を、前記複数の参照電圧値の組み合わせ変数に
関連付けて記憶された補正情報のうち、前記参照電圧記
憶手段に更新記憶されている複数の参照電圧値の組み合
わせに係る補正情報を用いて補正するとともに、当該補
正後の差分電圧値と、前記シャント抵抗の抵抗値とを参
照して、前記負荷回路に流れる電流値を演算する検出電
流補正手段と、を備え、前記差動増幅回路のうち、少な
くとも前記検出電圧差増幅手段及び前記複数の参照電圧
増幅手段は、参照電圧を直接補正用の電圧値として利用
するために相互に熱結合されてほぼ共通の温度環境とな
る如く集積させて設けられることを要旨とする。In order to solve the above-mentioned problems, the invention of claim 1 inserts a current value flowing in a load circuit configured by connecting a load to a DC power supply in series to the load circuit. A current detection device configured to detect from a voltage difference between terminals of a connected shunt resistor, the detected voltage difference amplifying means amplifying the voltage difference between terminals of the shunt resistor and outputting the amplified voltage difference signal as an analog form. A plurality of reference voltage amplifying means for respectively amplifying a plurality of reference voltages having mutually different values to output as analog reference voltage signals, a differential voltage signal output from the detected voltage difference amplifying means, and of the plurality of reference voltage signals respectively outputted from the plurality of reference voltage amplifying means, the voltage signal for sequentially selecting outputs based on the priority being decided either one voltage signal in advance And a A / D conversion circuit for converting an analog voltage signal input from the differential amplifier circuit into a digital voltage signal and outputting the digital voltage signal. Among the voltage signals input from the A / D conversion circuit, reference voltage storage means for respectively updating and storing a plurality of reference voltage values, and a temperature change of the differential amplifier circuit in association with a combination variable of the plurality of reference voltage values. When the correction information storage unit that stores the correction information used when correcting the detection error caused by the difference and the differential voltage value that represents the voltage difference between the terminals of the shunt resistor are input from the A / D conversion circuit, The correction information stored in association with the combination variable of the plurality of reference voltage values includes the detection error caused by the temperature change of the differential amplifier circuit, which is included in the input differential voltage value. Correction is performed using correction information relating to a combination of a plurality of reference voltage values updated and stored in the reference voltage storage means, and the corrected differential voltage value and the resistance value of the shunt resistor are referred to. A detection current correction means for calculating a value of a current flowing through the load circuit, wherein at least the detection voltage difference amplification means and the plurality of reference voltage amplification means of the differential amplification circuit directly correct the reference voltage. Use as voltage value for
In order to achieve this, the gist is that they are thermally coupled to each other and integrated so as to have a substantially common temperature environment.
【００１３】請求項１の発明によれば、まず、差動増幅
回路において、検出電圧差増幅手段は、シャント抵抗の
端子間電圧差を増幅してアナログ形態の差分電圧信号と
して出力する一方、複数の参照電圧増幅手段は、相互に
値が異なる複数の参照電圧をそれぞれ増幅してアナログ
形態の参照電圧信号として各々出力する。これを受け
て、差動増幅回路の一構成部材である電圧信号選択手段
は、検出電圧差増幅手段から出力される差分電圧信号
と、複数の参照電圧増幅手段から各々出力される複数の
参照電圧信号とのうち、いずれか１つの電圧信号を順次
選択出力する。ここで、差動増幅回路のうち、少なくと
も検出電圧差増幅手段及び複数の参照電圧増幅手段は、
相互に熱結合されてほぼ共通の温度環境となる如く設け
られている。次に、Ａ／Ｄ変換回路は、差動増幅回路か
ら入力したアナログ形態の電圧信号を、ディジタル形態
の電圧信号に変換して出力する。According to the first aspect of the present invention, first, in the differential amplifier circuit, the detection voltage difference amplifying means amplifies the voltage difference between the terminals of the shunt resistor and outputs it as a differential voltage signal in analog form. The reference voltage amplifying means amplifies a plurality of reference voltages having different values and outputs the amplified reference voltages as analog reference voltage signals. In response to this, the voltage signal selection means, which is a component of the differential amplification circuit, is configured to detect the differential voltage signal output from the detected voltage difference amplification means and the plurality of reference voltages output from the plurality of reference voltage amplification means. One of the voltage signals is sequentially selected and output. Here, in the differential amplifier circuit, at least the detection voltage difference amplification means and the plurality of reference voltage amplification means are
They are provided so as to be thermally coupled to each other to have a substantially common temperature environment. Next, the A / D conversion circuit converts the analog voltage signal input from the differential amplifier circuit into a digital voltage signal and outputs the voltage signal.
【００１４】また、参照電圧記憶手段は、Ａ／Ｄ変換回
路から入力した電圧信号のうち、複数の参照電圧値をそ
れぞれ更新記憶する一方、補正情報記憶手段は、複数の
参照電圧値の組み合わせ変数に関連付けて、差動増幅回
路の温度変化に起因する検出誤差を補正する際に用いら
れる補正情報を記憶している。Further, the reference voltage storage means updates and stores a plurality of reference voltage values among the voltage signals input from the A / D conversion circuit, while the correction information storage means stores a combination variable of the plurality of reference voltage values. The correction information used when correcting the detection error caused by the temperature change of the differential amplifier circuit is stored in association with
【００１５】そして、検出電流補正手段は、Ａ／Ｄ変換
回路からシャント抵抗の端子間電圧差を表す差分電圧値
が入力されたとき、入力された差分電圧値に内包されて
いる、差動増幅回路の温度変化に起因する検出誤差を、
複数の参照電圧値の組み合わせ変数に関連付けて記憶さ
れた補正情報のうち、参照電圧記憶手段に更新記憶され
ている複数の参照電圧値の組み合わせに係る補正情報を
用いて補正するとともに、補正後の差分電圧値と、シャ
ント抵抗の抵抗値とを参照して、負荷回路に流れる電流
値を演算する。When the difference voltage value representing the voltage difference between the terminals of the shunt resistor is input from the A / D conversion circuit, the detection current correction means includes a differential amplification included in the input difference voltage value. The detection error due to the temperature change of the circuit,
Of the correction information stored in association with the combination variables of the plurality of reference voltage values, the correction information related to the combination of the plurality of reference voltage values updated and stored in the reference voltage storage means is used for correction, and The current value flowing in the load circuit is calculated with reference to the differential voltage value and the resistance value of the shunt resistor.
【００１６】このように、請求項１の発明によれば、差
動増幅回路のうち、少なくとも検出電圧差増幅手段及び
複数の参照電圧増幅手段を、相互に熱結合させることで
ほぼ共通の温度環境となる如く設けておくとともに、差
動増幅回路から出力される複数の参照電圧値をそれぞれ
更新記憶する一方、複数の参照電圧値の組み合わせ変数
に関連付けて、差動増幅回路の温度変化に起因する検出
誤差を補正する際に用いられる補正情報を記憶してお
き、Ａ／Ｄ変換回路からシャント抵抗の端子間電圧差を
表す差分電圧値が入力されたとき、入力された差分電圧
値に内包されている、差動増幅回路の温度変化に起因す
る検出誤差を、複数の参照電圧値の組み合わせ変数に関
連付けて記憶された補正情報のうち、参照電圧記憶手段
に更新記憶されている複数の参照電圧値の組み合わせに
係る補正情報を用いて補正するようにしたので、差動増
幅回路に温度変化が生じた場合であっても、簡素な装置
構成をもって、差動増幅回路の温度変化に起因する検出
誤差を除去して、高精度の電流検出値を得ることができ
る。As described above, according to the first aspect of the present invention, in the differential amplifier circuit, at least the detected voltage difference amplifying means and the plurality of reference voltage amplifying means are thermally coupled to each other, so that the temperature environment is substantially common. The reference voltage values output from the differential amplifier circuit are updated and stored, respectively, while being associated with the combination variables of the plurality of reference voltage values and caused by the temperature change of the differential amplifier circuit. The correction information used when correcting the detection error is stored, and when the differential voltage value representing the voltage difference between the terminals of the shunt resistor is input from the A / D conversion circuit, it is included in the input differential voltage value. The detection error caused by the temperature change of the differential amplifier circuit is updated and stored in the reference voltage storage means among the correction information stored in association with the combination variables of the plurality of reference voltage values. Since the correction information related to the combination of the plurality of reference voltage values is used for correction, even when the temperature of the differential amplifier circuit changes, the temperature change of the differential amplifier circuit can be achieved with a simple device configuration. It is possible to remove the detection error caused by the above and obtain a highly accurate current detection value.
【００１７】また、請求項２の発明は、前記複数の参照
電圧値は、前記負荷回路に流れる電流値が零時における
オフセット電圧値と、前記負荷回路に流れる電流値が飽
和時における飽和電圧値との両者、又は少なくともいず
れか一方を含むことを要旨とする。According to a second aspect of the present invention, the plurality of reference voltage values are the offset voltage value when the current value flowing in the load circuit is zero and the saturation voltage value when the current value flowing in the load circuit is saturated. It is a gist to include both and at least one of them.
【００１８】さらに、請求項３の発明は、前記複数の参
照電圧値は、前記負荷回路に流れる電流値が零時におけ
るオフセット電圧値と、前記負荷回路に流れる電流値が
飽和時における飽和電圧値との間の電圧値となることを
妨げないことを要旨とする。Further, in the invention of claim 3, the plurality of reference voltage values are an offset voltage value when a current value flowing through the load circuit is zero and a saturation voltage value when the current value flowing through the load circuit is saturated. The gist is that it does not prevent the voltage value between and.
【００１９】しかも、請求項４の発明は、前記電圧信号
選択手段は、前記検出電圧差増幅手段から出力される差
分電圧信号と、前記複数の参照電圧増幅手段から各々出
力される参照電圧信号とを、所定時間以内に全て選択出
力することを要旨とする。Moreover, in the invention of claim 4, the voltage signal selecting means includes a differential voltage signal output from the detected voltage difference amplifying means and a reference voltage signal output from each of the plurality of reference voltage amplifying means. It is a gist to select and output all within a predetermined time.
【００２０】請求項４の発明によれば、電圧信号選択手
段は、検出電圧差増幅手段から出力される差分電圧信号
と、複数の参照電圧増幅手段から各々出力される参照電
圧信号とを、所定時間以内に全て選択出力するので、し
たがって、Ａ／Ｄ変換回路からシャント抵抗の端子間電
圧差を表す差分電圧値が入力されたとき、入力された差
分電圧値に内包されている、差動増幅回路の温度変化に
起因する検出誤差を、複数の参照電圧値の組み合わせ変
数に関連付けて記憶された補正情報のうち、所定時間以
内に参照電圧記憶手段で記憶更新された複数の参照電圧
値の組み合わせに係る補正情報を用いて補正することが
でき、この結果、差動増幅回路に温度変化が生じた場合
であっても、簡素な装置構成をもって、差動増幅回路の
温度変化に起因する検出誤差を除去して、高精度の電流
検出値を得ることができる。According to the fourth aspect of the present invention, the voltage signal selecting means determines the difference voltage signal output from the detected voltage difference amplifying means and the reference voltage signal output from each of the plurality of reference voltage amplifying means. All of them are selected and output within the time. Therefore, when the differential voltage value representing the voltage difference between the terminals of the shunt resistor is input from the A / D conversion circuit, the differential amplification included in the input differential voltage value. A combination of a plurality of reference voltage values stored and updated in the reference voltage storage means within a predetermined time, out of the correction information stored by associating the detection error caused by the temperature change of the circuit with the combination variable of the plurality of reference voltage values. It is possible to perform correction by using the correction information according to the above. As a result, even when the temperature of the differential amplifier circuit changes, the temperature change of the differential amplifier circuit is caused by a simple device configuration. Removing the detected error can be obtained a current detection value with high accuracy.
【００２１】また、請求項５の発明は、前記電圧信号選
択手段は、前記検出電圧差増幅手段から出力される差分
電圧信号と、前記複数の参照電圧増幅手段から各々出力
される参照電圧信号とのうち、参照電圧信号を優先的に
選択出力することを要旨とする。According to a fifth aspect of the present invention, the voltage signal selecting means includes a differential voltage signal output from the detected voltage difference amplifying means and a reference voltage signal output from each of the plurality of reference voltage amplifying means. Of these, the gist is to preferentially output the reference voltage signal.
【００２２】請求項５の発明によれば、電圧信号選択手
段は、検出電圧差増幅手段から出力される差分電圧信号
と、複数の参照電圧増幅手段から各々出力される参照電
圧信号とのうち、参照電圧信号を優先的に選択出力する
ので、したがって、シャント抵抗の端子間電圧差を表す
差分電圧値の取り込みに優先して、差動増幅回路の温度
変化に起因する検出誤差の補正準備が推進されることと
なり、結果として、高精度の電流検出値の取得に寄与す
ることができる。According to the fifth aspect of the invention, the voltage signal selecting means includes the differential voltage signal output from the detected voltage difference amplifying means and the reference voltage signal output from each of the plurality of reference voltage amplifying means. Since the reference voltage signal is preferentially selected and output, therefore, the preparation for correction of the detection error caused by the temperature change of the differential amplifier circuit is promoted in preference to the acquisition of the differential voltage value representing the voltage difference between the terminals of the shunt resistor. As a result, it is possible to contribute to acquisition of a highly accurate current detection value.
【００２３】そして、請求項６の発明は、前記検出電流
補正手段で演算された電流値と、所定の電流値とを比較
参照して、前記負荷回路に当該所定の電流値を越える過
電流が流れているか否かを判定するとともに、当該判定
結果に基づいて、前記負荷回路における過電流の供給を
遮断制御する過電流遮断制御手段をさらに備えて構成さ
れることを要旨とする。According to a sixth aspect of the present invention, the current value calculated by the detected current correction means is compared with a predetermined current value, and an overcurrent exceeding the predetermined current value is applied to the load circuit. The gist of the present invention is to further include an overcurrent cutoff control unit that determines whether or not the current is flowing, and cuts off the overcurrent supply in the load circuit based on the determination result.
【００２４】請求項６の発明によれば、過電流遮断制御
手段は、検出電流補正手段で演算された電流値と、所定
の電流値とを比較参照して、負荷回路に所定の電流値を
越える過電流が流れているか否かを判定するとともに、
この判定結果に基づいて、負荷回路における過電流の供
給を遮断制御するので、この結果、検出電流補正手段で
得られた高精度の電流検出値に基づいて、きわめて緻密
な過電流供給遮断制御を実現することができる。According to the sixth aspect of the present invention, the overcurrent interruption control means compares the current value calculated by the detected current correction means with a predetermined current value and refers to the predetermined current value in the load circuit. In addition to determining whether an overcurrent that exceeds the current is flowing,
Since the overcurrent supply in the load circuit is controlled to be cut off based on this determination result, as a result, extremely precise overcurrent supply cutoff control is performed based on the highly accurate current detection value obtained by the detected current correction means. Can be realized.
【００２５】[0025]
【発明の実施の形態】以下に、本発明に係る電流検出装
置の一実施形態について、図に基づいて詳細に説明す
る。BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a current detecting device according to the present invention will be described below in detail with reference to the drawings.
【００２６】図１は、本発明に係る電流検出装置を示す
概略ブロック構成図、図２は、本発明に係る電流検出装
置の主要部を示す概略ブロック構成図、図３（ａ），
（ｂ），（ｃ）は、本発明に係る電流検出装置の動作フ
ローチャート図、図４は、本発明に係る電流検出装置の
動作説明に供するタイムチャート図である。FIG. 1 is a schematic block configuration diagram showing a current detecting device according to the present invention, FIG. 2 is a schematic block configuration diagram showing a main part of the current detecting device according to the present invention, FIG. 3 (a),
(B) and (c) are operation flow charts of the current detection device according to the present invention, and FIG. 4 is a time chart diagram for explaining the operation of the current detection device according to the present invention.
【００２７】まず、本発明に係る電流検出装置１の概略
構成について述べると、電流検出装置１は、図１に示す
ように、所定電圧ＶD の供給源となる直流電源３に負荷
５を接続して構成される負荷回路６に流れる電流値ＩD
を、負荷回路６に直列に挿入接続された既知の低抵抗値
ＲS を呈するシャント抵抗７の端子間電圧差から検出す
る如く構成されている。First, the schematic configuration of the current detecting device 1 according to the present invention will be described. In the current detecting device 1, as shown in FIG. 1, a load 5 is connected to a DC power source 3 which is a supply source of a predetermined voltage V D. Current value I D flowing through the load circuit 6 configured as
Is detected from the voltage difference between the terminals of the shunt resistor 7 having a known low resistance value R S that is inserted and connected in series to the load circuit 6.
【００２８】負荷回路６には、例えばＭＯＳ型ＦＥＴ９
等の半導体スイッチが直列に挿入接続されており、電流
検出装置１が有する後述の過電流遮断制御機能を用い
て、負荷回路６に過電流が流れることを未然に阻止する
ようにしている。The load circuit 6 includes, for example, a MOS FET 9
These semiconductor switches are connected in series, and the overcurrent cutoff control function of the current detection device 1 described later is used to prevent overcurrent from flowing through the load circuit 6.
【００２９】さらに詳しく述べると、電流検出装置１
は、図１に示すように、シャント抵抗７と、ＭＯＳ型Ｆ
ＥＴ９と、シャント抵抗７における両端子の電圧ＶSA，
ＶSBをそれぞれ入力するとともに、端子間電圧差を増幅
してアナログ形態の差分電圧信号として出力する等の機
能を有する差動増幅回路（ＡＳＩＣ）１３と、差動増幅
回路１３から入力したアナログ形態の電圧信号を、ディ
ジタル形態の電圧信号に変換して出力するＡ／Ｄ変換回
路１５と、ＥＣＵ１７と、ＥＣＵ１７から入力したディ
ジタル形態の電圧信号を、アナログ形態の電圧信号ＶSH
に変換して出力するＤ／Ａ変換回路１９と、を備えて構
成されている。More specifically, the current detecting device 1
Is a shunt resistor 7 and a MOS type F as shown in FIG.
ET9 and the voltage V SA at both terminals of the shunt resistor 7,
A differential amplifier circuit (ASIC) 13 having a function of inputting V SB respectively and amplifying a voltage difference between terminals and outputting as a differential voltage signal in an analog form, and an analog form input from the differential amplifier circuit 13. Of the analog voltage signal V SH, the A / D conversion circuit 15 for converting the digital voltage signal of FIG. 1 to a digital voltage signal and outputting the digital voltage signal, the ECU 17, and the digital voltage signal input from the ECU 17.
And a D / A conversion circuit 19 for converting and outputting.
【００３０】差動増幅回路（ＡＳＩＣ）１３は、図２に
示すように、シャント抵抗７の端子間電圧差を増幅して
アナログ形態の差分電圧信号ＶDFとして出力する検出電
圧差増幅手段として機能する第１の差動増幅器ＡＭＰ１
と、相互に値が異なる第１及び第２の参照電圧信号Ｖ
REF ，ＶOFF をそれぞれ増幅してアナログ形態の第１及
び第２の参照電圧信号ＶREF ，ＶOFF として各々出力す
る複数の参照電圧増幅手段としてそれぞれ機能する第
２，第３の差動増幅器ＡＭＰ２，ＡＭＰ３と、第１の差
動増幅器ＡＭＰ１から出力される差分電圧信号ＶDFと、
第２，第３の差動増幅器ＡＭＰ２，ＡＭＰ３から各々出
力される第１及び第２の参照電圧信号ＶREF，ＶOFF と
のうち、いずれか１つの電圧信号を順次選択出力する電
圧信号選択手段として機能する第１乃至第３のマルチプ
レクサ３５，３７，３９等の信号切換器と、第１乃至第
３のマルチプレクサ３５，３７，３９のうち、いずれか
１つから選択的に入力された電圧信号を出力する電圧信
号選択手段として機能する論理和回路４１と、ＥＣＵ１
７から送出される切換制御信号にしたがって、第１乃至
第３のマルチプレクサ３５，３７，３９における信号経
路の切換制御を実行する一方、ＥＣＵ１７から過電流遮
断制御信号が入力されたとき、入力信号を所定の電圧信
号に変換して次述する第４の差動増幅器ＡＭＰ４へ出力
する電圧信号選択手段として機能するコントローラ４３
と、コントローラ４３から送出された電圧信号を増幅す
るとともに、増幅された電圧をＭＯＳ型ＦＥＴ９のゲー
トに印加し、ＭＯＳ型ＦＥＴ９のドレイン電流ＩD を遮
断することにより、負荷回路６に過電流が流れることを
未然に阻止する機能を有する第４の差動増幅器ＡＭＰ４
と、を備えて構成されている。As shown in FIG. 2, the differential amplifier circuit (ASIC) 13 functions as a detection voltage difference amplifying means for amplifying the voltage difference between the terminals of the shunt resistor 7 and outputting it as a differential voltage signal V DF in an analog form. First differential amplifier AMP1
And the first and second reference voltage signals V having different values from each other.
REF, second and third differential amplifiers which respectively function as a plurality of reference voltage amplifying means for respectively outputting the first and second reference voltage signal V REF, V OFF of analog form and amplifies each V OFF AMP2 , AMP3 and the differential voltage signal V DF output from the first differential amplifier AMP1,
Voltage signal selecting means for sequentially selecting and outputting any one of the first and second reference voltage signals V REF and V OFF output from the second and third differential amplifiers AMP2 and AMP3, respectively. Signal switchers such as the first to third multiplexers 35, 37, 39, etc. that function as the above, and the voltage signal selectively input from any one of the first to third multiplexers 35, 37, 39. AND circuit 41 that functions as a voltage signal selection unit that outputs
In accordance with the switching control signal sent from 7, the signal path switching control in the first to third multiplexers 35, 37, 39 is executed, while the input signal is changed when the overcurrent cutoff control signal is input from the ECU 17. A controller 43 that functions as a voltage signal selection unit that converts the voltage signal into a predetermined voltage signal and outputs the voltage signal to a fourth differential amplifier AMP4 described below.
By amplifying the voltage signal sent from the controller 43 and applying the amplified voltage to the gate of the MOS type FET 9 to cut off the drain current I D of the MOS type FET 9, an overcurrent is applied to the load circuit 6. Fourth differential amplifier AMP4 having a function of blocking the flow
And are provided.
【００３１】なお、差動増幅回路１３の各種構成部材
は、相互に熱結合されてほぼ共通の温度環境となる如
く、１つの特定用途向け集積回路、いわゆるＡＳＩＣに
集積させて設けられている。The various components of the differential amplifier circuit 13 are integrated and provided in one application-specific integrated circuit, a so-called ASIC, so that they are thermally coupled to each other and have a substantially common temperature environment.
【００３２】また、差動増幅回路１３の各種構成部材の
うち、少なくとも第１の差動増幅器ＡＭＰ１、及び第
２，第３の差動増幅器ＡＭＰ２，ＡＭＰ３を、相互に熱
結合されてほぼ共通の温度環境となる如く設ける構成を
採用することもできる。Further, among the various components of the differential amplifier circuit 13, at least the first differential amplifier AMP1 and the second and third differential amplifiers AMP2 and AMP3 are thermally coupled to each other and are substantially common. It is also possible to employ a configuration in which the temperature environment is provided.
【００３３】本発明に係る電流検出装置１では、差動増
幅回路１３の各種構成部材のうち、少なくとも第１乃至
第３の差動増幅器ＡＭＰ１，ＡＭＰ２，ＡＭＰ３を、相
互に熱結合されてほぼ共通の温度環境となる如く設ける
構成を採用しているので、第１乃至第３の差動増幅器Ａ
ＭＰ１，ＡＭＰ２，ＡＭＰ３はほぼ共通の温度環境とな
る。In the current detecting device 1 according to the present invention, at least the first to third differential amplifiers AMP1, AMP2, AMP3 among the various constituent members of the differential amplifier circuit 13 are thermally coupled to each other and are substantially common. Therefore, the first to third differential amplifiers A are used.
MP1, AMP2, and AMP3 have almost common temperature environments.
【００３４】したがって、各自の差動増幅器を共通仕様
に統一しておけば、各差動増幅器に温度変化が生じた際
の、各差動増幅器間のゲインの変動及びドリフト量、つ
まり電流検出誤差の発生要因を、ほぼ横並びに整合して
変位するものとして取り扱うことができ、この結果、各
差動増幅器における電流検出誤差を補正する際に用いら
れる補正情報を、比較的単純化して構成することができ
る。Therefore, if the respective differential amplifiers are unified to have the common specifications, the variation and the drift amount of the gain between the differential amplifiers, that is, the current detection error, when the temperature of each differential amplifier changes. It is possible to treat the generation factors of the above as being displaced in a substantially horizontal alignment, and as a result, the correction information used when correcting the current detection error in each differential amplifier should be relatively simplified and configured. You can
【００３５】ＥＣＵ１７は、各種演算処理を行う図示し
ないＣＰＵ、プログラムを格納する図示しないＲＯＭ、
及びデータ等を格納する図示しないＲＡＭ等を含んで構
成されており、指令制御部２１と、参照電圧記憶手段と
して機能する参照電圧記憶部２３と、補正情報記憶手段
として機能する補正情報記憶部２５と、検出電流補正手
段として機能する検出電流補正部２７と、過電流遮断制
御手段として機能する過電流判定部２９と、を含んで構
成されている。The ECU 17 includes a CPU (not shown) for performing various arithmetic processes, a ROM (not shown) for storing programs,
And a RAM (not shown) that stores data and the like, and includes a command control unit 21, a reference voltage storage unit 23 that functions as a reference voltage storage unit, and a correction information storage unit 25 that functions as a correction information storage unit. And a detection current correction unit 27 that functions as a detection current correction unit, and an overcurrent determination unit 29 that functions as an overcurrent cutoff control unit.
【００３６】指令制御部２１は、差動増幅回路１３に内
蔵されたコントローラ４３へ各種切換制御信号を送出す
る機能を有している。The command controller 21 has a function of sending various switching control signals to the controller 43 built in the differential amplifier circuit 13.
【００３７】参照電圧記憶部２３は、Ａ／Ｄ変換回路１
５から入力した電圧信号のうち、第１及び第２の参照電
圧値ＶREF ，ＶOFF をそれぞれ更新記憶する機能を有し
ている。The reference voltage storage unit 23 includes the A / D conversion circuit 1
It has a function of updating and storing the first and second reference voltage values V REF and V OFF of the voltage signal input from the circuit 5.
【００３８】補正情報記憶部２５は、第１及び第２の参
照電圧値ＶREF ，ＶOFF の組み合わせ変数に関連付け
て、差動増幅回路１３の温度変化に起因する電流検出誤
差を補正する際に用いられる補正情報を記憶する機能を
有している。The correction information storage unit 25 relates to the combination variable of the first and second reference voltage values V REF and V OFF to correct the current detection error caused by the temperature change of the differential amplifier circuit 13. It has a function of storing the correction information used.
【００３９】検出電流補正部２７は、Ａ／Ｄ変換回路１
５からシャント抵抗７の端子間電圧差を表す差分電圧値
ＶDFが入力されたとき、入力された差分電圧値ＶDFに内
包されている、差動増幅回路１３の温度変化に起因する
検出誤差を、補正情報記憶部２５に記憶された補正情報
のうち、参照電圧記憶部２３に更新記憶されている第１
及び第２の参照電圧値ＶREF ，ＶOFF の組み合わせに係
る補正情報を用いて補正するとともに、補正後の差分電
圧値と、シャント抵抗７の抵抗値ＲS とを参照して、負
荷回路６に流れる電流値ＩD を演算する機能を有してい
る。The detected current correction unit 27 is composed of the A / D conversion circuit 1
When the differential voltage value V DF representing the voltage difference between the terminals of the shunt resistor 7 is input from 5, the detection error due to the temperature change of the differential amplifier circuit 13 included in the input differential voltage value V DF. Of the correction information stored in the correction information storage unit 25, the first stored in the reference voltage storage unit 23 is updated and stored.
And the second reference voltage values V REF and V OFF are corrected using the correction information, and the differential voltage value after correction and the resistance value R S of the shunt resistor 7 are referenced to refer to the load circuit 6 It has a function of calculating the value I D of the current flowing through.
【００４０】次に、本発明に係る電流検出装置１の動作
について、図３（ａ），（ｂ），（ｃ）に示す動作フロ
ーチャートにしたがって、図４に示すタイムチャート図
を参照しつつ詳細に説明する。Next, the operation of the current detecting device 1 according to the present invention will be described in detail with reference to the time chart shown in FIG. 4 in accordance with the operation flowcharts shown in FIGS. 3 (a), 3 (b) and 3 (c). Explained.
【００４１】なお、ＥＣＵ１７において実行されるプロ
グラムとしては、図３（ａ）に示すメインルーチンプロ
グラムと、図３（ｂ），（ｃ）に示す割り込みプログラ
ムとしての第１及び第２のサブルーチンプログラムＳＵ
Ｂ１，ＳＵＢ２が存在するが、各プログラムの割り込み
優先度は、優先度が高い順に並べると、第２のサブルー
チンプログラムＳＵＢ２、第１のサブルーチンプログラ
ムＳＵＢ１、メインルーチンプログラムとなる如くあら
かじめ設定されている。すなわち、本発明において、電
圧信号選択手段は、検出電圧差増幅手段から出力される
差分電圧信号と、複数の参照電圧増幅手段から各々出力
される参照電圧信号とのうち、参照電圧信号を優先的に
選択出力する如く構成されている。The programs executed in the ECU 17 are a main routine program shown in FIG. 3A and first and second subroutine programs SU as interrupt programs shown in FIGS. 3B and 3C.
Although there are B1 and SUB2, the interrupt priority of each program is set in advance so as to become the second subroutine program SUB2, the first subroutine program SUB1, and the main routine program when they are arranged in the descending order of priority. That is, in the present invention, the voltage signal selection means preferentially selects the reference voltage signal among the differential voltage signal output from the detection voltage difference amplification means and the reference voltage signal output from each of the plurality of reference voltage amplification means. It is configured to selectively output to.
【００４２】したがって、あるプログラムの実行中に、
これより優先度が高いプログラムの割り込みが発生した
とき、実行中のプログラムを中断させて、割り込みプロ
グラムが優先的に実行されることになる。すなわち、本
発明において、電圧信号選択手段は、検出電圧差増幅手
段から出力される差分電圧信号と、複数の参照電圧増幅
手段から各々出力される参照電圧信号とのうち、参照電
圧信号を優先的に選択出力するので、したがって、シャ
ント抵抗７の端子間電圧差を表す差分電圧値の取り込み
に優先して、差動増幅回路１３の温度変化に起因する検
出誤差の補正準備が推進されることとなり、結果とし
て、高精度の電流検出値の取得に寄与することができ
る。Therefore, during execution of a program,
When an interrupt of a program with a higher priority than this occurs, the program being executed is interrupted and the interrupt program is executed with priority. That is, in the present invention, the voltage signal selection means preferentially selects the reference voltage signal among the differential voltage signal output from the detection voltage difference amplification means and the reference voltage signal output from each of the plurality of reference voltage amplification means. Therefore, the preparation for the correction of the detection error caused by the temperature change of the differential amplifier circuit 13 is promoted prior to the acquisition of the differential voltage value representing the voltage difference between the terminals of the shunt resistor 7. As a result, it is possible to contribute to the acquisition of a highly accurate current detection value.
【００４３】さて、はじめに、第１及び第２のサブルー
チンプログラムＳＵＢ１，ＳＵＢ２の動作についてそれ
ぞれ説明する。Now, first, the operations of the first and second subroutine programs SUB1 and SUB2 will be described.
【００４４】まず、図３（ｂ）に示す第１のサブルーチ
ンプログラムＳＵＢ１では、指令制御部２１は、差動増
幅回路１３に内蔵されたコントローラ４３へ、第２のマ
ルチプレクサ３７における信号経路の閉止切換制御を実
行させる旨の切換制御信号ＲＥＱ１のハイ（Ｈ）状態を
送出する（図４参照）。これを受けて、ＭＯＳ型ＦＥＴ
９は、オン状態に切り換えられて負荷回路６に電流を流
す一方、第２のマルチプレクサ３７は、信号経路の閉止
切換制御を実行させる。すると、差動増幅回路１３は、
第２の差動増幅器ＡＭＰ２から出力されるアナログ形態
の第１の参照電圧信号ＶREF を選択出力する。Ａ／Ｄ変
換回路１５は、差動増幅回路１３から入力したアナログ
形態の第１の参照電圧信号ＶREF を、ディジタル形態の
第１の参照電圧信号ＶREF に変換して出力し、図４の
に示すように、変換後の第１の参照電圧信号ＶREF が、
参照電圧記憶部２３に入力される（ステップＳ１１）。
これを受けて、参照電圧記憶部２３は、Ａ／Ｄ変換回路
１５から入力した第１の参照電圧値ＶREF を更新記憶し
て（ステップＳ１２）、この更新記憶後に、ＥＣＵ１７
は、第１のサブルーチンプログラムＳＵＢ１を終了させ
て、処理の流れをメインルーチンプログラムに戻す。First, in the first subroutine program SUB1 shown in FIG. 3B, the command control section 21 switches the signal path in the second multiplexer 37 to the controller 43 incorporated in the differential amplifier circuit 13. The high (H) state of the switching control signal REQ1 for executing the control is sent (see FIG. 4). In response to this, MOS type FET
9 is switched to the ON state to allow a current to flow through the load circuit 6, while the second multiplexer 37 executes signal path closing switching control. Then, the differential amplifier circuit 13
The first reference voltage signal V REF in an analog form output from the second differential amplifier AMP2 is selectively output. The A / D conversion circuit 15 converts the analog first reference voltage signal V REF input from the differential amplifier circuit 13 into a digital first reference voltage signal V REF and outputs the converted first reference voltage signal V REF . As shown in, the converted first reference voltage signal V REF is
It is input to the reference voltage storage unit 23 (step S11).
In response to this, the reference voltage storage unit 23 updates and stores the first reference voltage value V REF input from the A / D conversion circuit 15 (step S12), and after this update storage, the ECU 17
Terminates the first subroutine program SUB1 and returns the flow of processing to the main routine program.
【００４５】一方、図３（ｃ）に示す第２のサブルーチ
ンプログラムＳＵＢ２では、指令制御部２１は、差動増
幅回路１３に内蔵されたコントローラ４３へ、第３のマ
ルチプレクサ３９における信号経路の閉止切換制御を実
行させる旨の切換制御信号ＲＥＱ２のハイ（Ｈ）状態を
送出する（図４参照）。これを受けて、ＭＯＳ型ＦＥＴ
９は、オン状態に切り換えられて負荷回路６に電流を流
す一方、第３のマルチプレクサ３７は、信号経路の閉止
切換制御を実行させる。すると、差動増幅回路１３は、
第３の差動増幅器ＡＭＰ３から出力されるアナログ形態
の第２の参照電圧信号ＶOFF を選択出力する。Ａ／Ｄ変
換回路１５は、差動増幅回路１３から入力したアナログ
形態の第２の参照電圧信号ＶOFF を、ディジタル形態の
第２の参照電圧信号ＶOFF に変換して出力し、図４の
に示すように、変換後の第２の参照電圧信号ＶOFF が、
参照電圧記憶部２３に入力される（ステップＳ２１）。
これを受けて、参照電圧記憶部２３は、Ａ／Ｄ変換回路
１５から入力した第２の参照電圧値ＶOFF を更新記憶し
て（ステップＳ２２）、この更新記憶後に、ＥＣＵ１７
は、第２のサブルーチンプログラムＳＵＢ２を終了させ
て、処理の流れをメインルーチンプログラムに戻す。On the other hand, in the second subroutine program SUB2 shown in FIG. 3 (c), the command control section 21 switches the signal path in the third multiplexer 39 to the controller 43 incorporated in the differential amplifier circuit 13 to close it. The high (H) state of the switching control signal REQ2 for executing the control is sent (see FIG. 4). In response to this, MOS type FET
9 is switched to the ON state to allow a current to flow through the load circuit 6, while the third multiplexer 37 executes the closing switching control of the signal path. Then, the differential amplifier circuit 13
The second reference voltage signal V OFF in the analog form output from the third differential amplifier AMP3 is selectively output. The A / D conversion circuit 15 converts the analog second reference voltage signal V OFF input from the differential amplifier circuit 13 into a digital second reference voltage signal V OFF , and outputs the second reference voltage signal V OFF . As shown in, the converted second reference voltage signal V OFF is
It is input to the reference voltage storage unit 23 (step S21).
In response to this, the reference voltage storage unit 23 updates and stores the second reference voltage value V OFF input from the A / D conversion circuit 15 (step S22), and after this update storage, the ECU 17
Terminates the second subroutine program SUB2 and returns the flow of processing to the main routine program.
【００４６】なお、本実施形態において、電圧信号選択
手段の一部を構成する指令制御部２１は、好ましくは、
第１の差動増幅器ＡＭＰ１から出力される差分電圧信号
ＶDFと、第２，第３の差動増幅器ＡＭＰ２，ＡＭＰ３か
ら各々出力される第１及び第２の参照電圧信号ＶREF ，
ＶOFF とを、所定時間以内に全て選択出力する如く切換
制御信号を送出する構成を採用することができる。この
ようにすれば、指令制御部２１は、Ａ／Ｄ変換回路１５
からシャント抵抗７の端子間電圧差を表す差分電圧値Ｖ
DFが入力されたとき、入力された差分電圧値ＶDFに内包
されている、差動増幅回路１３の温度変化に起因する電
流検出誤差を、補正情報記憶部２５に記憶されている補
正情報のうち、所定時間以内に参照電圧記憶部２３で記
憶更新された第１及び第２の参照電圧値ＶREF ，ＶOFF
の組み合わせに係る補正情報を用いて補正することがで
き、この結果、差動増幅回路１３に温度変化が生じた場
合であっても、簡素な装置構成をもって、差動増幅回路
１３の温度変化に起因する検出誤差を除去して、きわめ
て高精度の電流検出値を得ることができる。In this embodiment, the command control section 21 forming a part of the voltage signal selection means is preferably
The differential voltage signal V DF output from the first differential amplifier AMP1 and the first and second reference voltage signals V REF output from the second and third differential amplifiers AMP2 and AMP3, respectively.
A configuration can be adopted in which the switching control signal is sent so that all V OFF is selectively output within a predetermined time. With this configuration, the command control unit 21 causes the A / D conversion circuit 15
To the differential voltage value V representing the voltage difference between the terminals of the shunt resistor 7
When DF is input, the current detection error due to the temperature change of the differential amplifier circuit 13, which is included in the input differential voltage value V DF , is corrected by the correction information stored in the correction information storage unit 25. Of these, the first and second reference voltage values V REF and V OFF stored and updated in the reference voltage storage unit 23 within a predetermined time
It is possible to perform correction using the correction information related to the combination, and as a result, even if the temperature of the differential amplifier circuit 13 changes, the temperature change of the differential amplifier circuit 13 can be prevented with a simple device configuration. It is possible to obtain a highly accurate current detection value by removing the detection error caused by it.
【００４７】また、本実施形態では、好ましくは、第１
のサブルーチンプログラムＳＵＢ１で用いられる第１の
参照電圧値ＶREF として、負荷回路６に流れる電流値が
飽和時における飽和電圧値を設定する一方、第２のサブ
ルーチンプログラムＳＵＢ２で用いられる第２の参照電
圧値ＶOFF として、負荷回路６に流れる電流値が零時に
おけるオフセット電圧値を設定する形態を採用すること
ができる。Further, in this embodiment, preferably, the first
As the first reference voltage value V REF used in the subroutine program SUB1, the saturation voltage value when the current value flowing in the load circuit 6 is saturated is set, while the second reference voltage used in the second subroutine program SUB2 is set. As the value V OFF , it is possible to adopt a mode in which an offset voltage value when the current value flowing through the load circuit 6 is zero is set.
【００４８】次に、ＥＣＵ１７において実行されるメイ
ンルーチンプログラムについて説明する。Next, the main routine program executed by the ECU 17 will be described.
【００４９】図３（ａ）に示すように、まず、指令制御
部２１は、差動増幅回路１３に内蔵されたコントローラ
４３へ、ＭＯＳ型ＦＥＴ９のオン切換制御を実行させる
旨の切換制御信号ＳIGのハイ（Ｈ）状態を送出する（図
４参照）。これを受けて、ＭＯＳ型ＦＥＴ９は、オン状
態に切り換えられて負荷回路６に電流を流す一方、第１
のマルチプレクサ３５は、信号経路の閉止切換制御を実
行させる。すると、差動増幅回路１３は、第１の差動増
幅器ＡＭＰ１から出力されるアナログ形態の差分電圧信
号ＶDFを選択出力する。Ａ／Ｄ変換回路１５は、差動増
幅回路１３から入力したアナログ形態の差分電圧信号Ｖ
DFを、ディジタル形態の差分電圧信号ＶDFに変換して出
力し、変換後の差分電圧信号ＶDF（図４の通常モード時
参照）が、検出電流補正部２７に入力される（ステッ
プＳ１）。As shown in FIG. 3 (a), first, the command control section 21 causes the controller 43 built in the differential amplifier circuit 13 to execute the switching control signal S to execute the ON switching control of the MOS FET 9. It sends the high (H) state of IG (see FIG. 4). In response to this, the MOS type FET 9 is switched to the ON state to flow a current through the load circuit 6, while the first type
The multiplexer 35 of 5 executes the closing switching control of the signal path. Then, the differential amplifier circuit 13 selectively outputs the analog differential voltage signal V DF output from the first differential amplifier AMP1. The A / D conversion circuit 15 receives the analog differential voltage signal V input from the differential amplifier circuit 13.
The DF is converted into a differential voltage signal V DF in digital form and output, and the converted differential voltage signal V DF (see the normal mode in FIG. 4) is input to the detection current correction unit 27 (step S1). .
【００５０】検出電流補正部２７は、Ａ／Ｄ変換回路１
５からシャント抵抗７の端子間電圧差を表す差分電圧値
ＶDFが入力されたとき、入力された差分電圧値ＶDFに内
包されている、差動増幅回路１３の温度変化に起因する
電流検出誤差を、補正情報記憶部２５に記憶されている
補正情報のうち、参照電圧記憶部２３に更新記憶されて
いる第１及び第２の参照電圧信号ＶREF ，ＶOFF の組み
合わせに係る補正情報を用いて補正するとともに、補正
後の差分電圧値と、シャント抵抗７の抵抗値ＲS とを参
照して、負荷回路６に流れる電流値ＩD を演算する（ス
テップＳ２）。The detected current correction unit 27 is composed of the A / D conversion circuit 1
When the differential voltage value V DF representing the voltage difference between the terminals of the shunt resistor 7 is input from 5, the current detection due to the temperature change of the differential amplifier circuit 13 included in the input differential voltage value V DF is detected. Among the correction information stored in the correction information storage unit 25, the error is corrected information related to the combination of the first and second reference voltage signals V REF and V OFF updated and stored in the reference voltage storage unit 23. The current value I D flowing through the load circuit 6 is calculated with reference to the corrected differential voltage value and the resistance value R S of the shunt resistor 7 as well as correction (step S2).
【００５１】ここで、補正情報記憶部２５に記憶されて
いる補正情報の作成例を述べると、補正情報は、例え
ば、まず、第２の参照電圧値ＶOFF として設定される、
負荷回路６に流れる電流値が零時におけるオフセット電
圧値から、第１の参照電圧値ＶREF として設定される、
負荷回路６に流れる電流値が飽和時における飽和電圧値
に至る迄の電圧領域を、例えば１６、３２、６４等の適
宜の数に等分分割することで複数の分割領域を作成して
おき、各分割領域毎に、複数の参照電圧値の組み合わせ
変数に関連付けて、差動増幅回路１３の温度変化に起因
する電流検出誤差を補正する際に用いる補正係数を書き
込むことにより作成することができる。Here, to describe an example of creating the correction information stored in the correction information storage unit 25, the correction information is first set as the second reference voltage value V OFF , for example.
From the offset voltage value when the current value flowing through the load circuit 6 is zero, it is set as the first reference voltage value V REF .
A plurality of divided regions are created by equally dividing the voltage region until the current value flowing through the load circuit 6 reaches the saturated voltage value at the time of saturation into an appropriate number such as 16, 32, 64, It can be created by writing a correction coefficient used for correcting a current detection error caused by a temperature change of the differential amplifier circuit 13 in association with each combination variable of a plurality of reference voltage values for each divided area.
【００５２】次に、過電流判定部２９は、検出電流補正
部２７で演算された電流値ＩD と、所定の電流値とを比
較参照して、負荷回路６に所定の電流値を越える過電流
が流れているか否かを判定する（ステップＳ３）。Next, the overcurrent determination unit 29 compares and references the current value I D calculated by the detected current correction unit 27 with a predetermined current value to cause the load circuit 6 to exceed the predetermined current value. It is determined whether or not current is flowing (step S3).
【００５３】ステップＳ３の過電流判定の結果、ＥＣＵ
１７は、負荷回路６に所定の電流値を越える過電流が流
れていないと判定されたとき、処理の流れをステップＳ
１に戻し、以下の処理を繰り返し実行する一方、負荷回
路６に所定の電流値を越える過電流が流れていると判定
されたとき、負荷回路６における過電流の供給を遮断す
る過電流供給遮断処理を実行する（ステップＳ４）。こ
の結果、検出電流補正部２７で得られた高精度の電流検
出値に基づいて、きわめて緻密な過電流供給遮断制御を
実現することができる。As a result of the overcurrent determination in step S3, the ECU
When it is determined that the overcurrent exceeding the predetermined current value does not flow in the load circuit 6, the processing flow 17 is performed in step S
While returning to 1, the following process is repeatedly executed, and when it is determined that the overcurrent exceeding the predetermined current value is flowing in the load circuit 6, the overcurrent supply cutoff that cuts off the overcurrent supply in the load circuit 6 is performed. The process is executed (step S4). As a result, based on the highly accurate current detection value obtained by the detected current correction unit 27, it is possible to realize extremely precise overcurrent supply interruption control.
【００５４】このように、本発明に係る電流検出装置に
よれば、差動増幅回路のうち、少なくとも検出電圧差増
幅手段及び複数の参照電圧増幅手段を、相互に熱結合さ
せることでほぼ共通の温度環境となる如く設けておくと
ともに、差動増幅回路から出力される複数の参照電圧値
をそれぞれ更新記憶する一方、複数の参照電圧値の組み
合わせ変数に関連付けて、差動増幅回路の温度変化に起
因する検出誤差を補正する際に用いられる補正情報を記
憶しておき、Ａ／Ｄ変換回路からシャント抵抗の端子間
電圧差を表す差分電圧値が入力されたとき、入力された
差分電圧値に内包されている、差動増幅回路の温度変化
に起因する検出誤差を、複数の参照電圧値の組み合わせ
変数に関連付けて記憶された補正情報のうち、参照電圧
記憶手段に更新記憶されている複数の参照電圧値の組み
合わせに係る補正情報を用いて補正するようにしたの
で、差動増幅回路に温度変化が生じた場合であっても、
簡素な装置構成をもって、差動増幅回路の温度変化に起
因する検出誤差を除去して、高精度の電流検出値を得る
ことができる。As described above, according to the current detecting device of the present invention, at least the detection voltage difference amplifying means and the plurality of reference voltage amplifying means in the differential amplifying circuit are thermally coupled to each other to be substantially common. The reference voltage values output from the differential amplifier circuit are updated and stored, respectively, while the temperature environment is set so that the temperature change of the differential amplifier circuit can be realized by associating with the combination variable of the reference voltage values. Correction information used when correcting the detection error caused is stored, and when the differential voltage value representing the terminal voltage difference of the shunt resistor is input from the A / D conversion circuit, the input differential voltage value is The detection error due to the temperature change of the differential amplifier circuit included therein is updated in the reference voltage storage means among the correction information stored in association with the combination variable of the plurality of reference voltage values. Since so as to correct by using the correction information according to the combination of a plurality of reference voltage values are, even when a temperature change occurs in the differential amplifier circuit,
With a simple device configuration, it is possible to eliminate a detection error caused by a temperature change of the differential amplifier circuit and obtain a highly accurate current detection value.
【００５５】以上詳細に説明したが、本発明は、上述し
た実施形態の例に限定されることなく、適宜の変更を加
えることにより、その他の態様で実施することができ
る。Although described in detail above, the present invention is not limited to the examples of the embodiments described above, but can be implemented in other modes by making appropriate modifications.
【００５６】すなわち、例えば、本実施形態中、複数の
参照電圧値の設定形態として、第１のサブルーチンプロ
グラムＳＵＢ１で用いられる第１の参照電圧値ＶREF と
して、負荷回路６に流れる電流値が飽和時における飽和
電圧値を設定する一方、第２のサブルーチンプログラム
ＳＵＢ２で用いられる第２の参照電圧値ＶOFF として、
負荷回路６に流れる電流値が零時におけるオフセット電
圧値を設定する形態を例示して説明したが、本発明は、
これに限定されるものではなく、例えば、第１の参照電
圧値ＶREF として、負荷回路６に流れる電流値が零時に
おけるオフセット電圧値と、負荷回路６に流れる電流値
が飽和時における飽和電圧値との中間領域に存在する適
宜の電圧値を設定する一方、第２の参照電圧値ＶOFF と
して、負荷回路６に流れる電流値が零時におけるオフセ
ット電圧値を設定する形態を採用することもできる。That is, for example, in the present embodiment, as the setting mode of a plurality of reference voltage values, the current value flowing through the load circuit 6 is saturated as the first reference voltage value V REF used in the first subroutine program SUB1. While setting the saturation voltage value at the time, as the second reference voltage value V OFF used in the second subroutine program SUB2,
Although the form of setting the offset voltage value when the current value flowing through the load circuit 6 is zero has been described as an example, the present invention is
For example, the first reference voltage value V REF is not limited to this, and the offset voltage value when the current value flowing through the load circuit 6 is zero and the saturation voltage when the current value flowing through the load circuit 6 is saturated are set. It is also possible to adopt a mode in which, while setting an appropriate voltage value existing in an intermediate region between the values, the second reference voltage value V OFF is set as an offset voltage value when the current value flowing through the load circuit 6 is zero. it can.
【００５７】また、上記形態以外にも、例えば、第１の
参照電圧値ＶREF として、負荷回路６に流れる電流値が
飽和時における飽和電圧値を設定する一方、第２の参照
電圧値ＶOFF として、負荷回路６に流れる電流値が零時
におけるオフセット電圧値と、負荷回路６に流れる電流
値が飽和時における飽和電圧値との中間領域に存在する
適宜の電圧値を設定する形態を採用することもできる。In addition to the above-described form, for example, as the first reference voltage value V REF , the saturation voltage value when the current value flowing through the load circuit 6 is saturated is set, while the second reference voltage value V OFF is set. As an example, a mode is adopted in which an appropriate voltage value existing in an intermediate region between the offset voltage value when the current value flowing in the load circuit 6 is zero and the saturation voltage value when the current value flowing in the load circuit 6 is saturated is adopted. You can also
【００５８】すなわち、本発明では、参照電圧値とし
て、負荷回路６に流れる電流値が零時におけるオフセッ
ト電圧値から、負荷回路６に流れる電流値が飽和時にお
ける飽和電圧値に至る迄の電圧領域のうち、適宜の電圧
値を複数設定すればよい。That is, in the present invention, as the reference voltage value, the voltage range from the offset voltage value when the current value flowing through the load circuit 6 is zero to the saturation voltage value when the current value flowing through the load circuit 6 is saturated. Of these, a plurality of appropriate voltage values may be set.
【００５９】最後に、本実施形態中、複数の参照電圧値
として、一対の参照電圧値を採用する形態を例示して説
明したが、本発明はこの形態のみに限定されることな
く、３つ以上の複数の参照電圧値を適宜採用することが
できることは言うまでもない。Lastly, in the present embodiment, a mode in which a pair of reference voltage values is adopted as the plurality of reference voltage values has been described as an example, but the present invention is not limited to this mode and three reference voltage values are used. It goes without saying that the above plurality of reference voltage values can be appropriately adopted.
【００６０】[0060]
【発明の効果】請求項１の発明によれば、差動増幅回路
のうち、少なくとも検出電圧差増幅手段及び複数の参照
電圧増幅手段を、相互に熱結合させることでほぼ共通の
温度環境となる如く設けておくとともに、差動増幅回路
から出力される複数の参照電圧値をそれぞれ更新記憶す
る一方、複数の参照電圧値の組み合わせ変数に関連付け
て、差動増幅回路の温度変化に起因する検出誤差を補正
する際に用いられる補正情報を記憶しておき、Ａ／Ｄ変
換回路からシャント抵抗の端子間電圧差を表す差分電圧
値が入力されたとき、入力された差分電圧値に内包され
ている、差動増幅回路の温度変化に起因する検出誤差
を、複数の参照電圧値の組み合わせ変数に関連付けて記
憶された補正情報のうち、参照電圧記憶手段に更新記憶
されている複数の参照電圧値の組み合わせに係る補正情
報を用いて補正するようにしたので、差動増幅回路に温
度変化が生じた場合であっても、簡素な装置構成をもっ
て、差動増幅回路の温度変化に起因する検出誤差を除去
して、高精度の電流検出値を得ることができる。According to the first aspect of the present invention, in the differential amplifier circuit, at least the detected voltage difference amplifying means and the plurality of reference voltage amplifying means are thermally coupled to each other, so that a substantially common temperature environment is obtained. In this way, the plurality of reference voltage values output from the differential amplifier circuit are respectively updated and stored, and the detection error caused by the temperature change of the differential amplifier circuit is associated with the combination variable of the plurality of reference voltage values. When the differential voltage value representing the voltage difference between the terminals of the shunt resistor is input from the A / D conversion circuit, the correction information used for correcting the error is stored and included in the input differential voltage value. Among the correction information stored by associating the detection error caused by the temperature change of the differential amplifier circuit with the combination variables of the plurality of reference voltage values, the plurality of reference information updated and stored in the reference voltage storage means. Since the correction is performed using the correction information related to the combination of the voltage values, even if the temperature of the differential amplifier circuit changes, the temperature change of the differential amplifier circuit is caused by the simple device configuration. By removing the detection error, a highly accurate current detection value can be obtained.
【００６１】また、請求項４の発明によれば、電圧信号
選択手段は、検出電圧差増幅手段から出力される差分電
圧信号と、複数の参照電圧増幅手段から各々出力される
参照電圧信号とを、所定時間以内に全て選択出力するの
で、したがって、Ａ／Ｄ変換回路からシャント抵抗の端
子間電圧差を表す差分電圧値が入力されたとき、入力さ
れた差分電圧値に内包されている、差動増幅回路の温度
変化に起因する検出誤差を、複数の参照電圧値の組み合
わせ変数に関連付けて記憶された補正情報のうち、所定
時間以内に参照電圧記憶手段で記憶更新された複数の参
照電圧値の組み合わせに係る補正情報を用いて補正する
ことができ、この結果、差動増幅回路に温度変化が生じ
た場合であっても、簡素な装置構成をもって、差動増幅
回路の温度変化に起因する検出誤差を除去して、高精度
の電流検出値を得ることができる。Further, according to the invention of claim 4, the voltage signal selecting means selects the differential voltage signal output from the detected voltage difference amplifying means and the reference voltage signal output from each of the plurality of reference voltage amplifying means. , All of them are selected and output within a predetermined time. Therefore, when the differential voltage value representing the terminal voltage difference of the shunt resistor is input from the A / D conversion circuit, the difference voltage value included in the input differential voltage value is Of the correction information stored by associating the detection error caused by the temperature change of the dynamic amplifier circuit with the combination variable of the plurality of reference voltage values, the plurality of reference voltage values stored and updated in the reference voltage storage means within a predetermined time. It is possible to perform correction using the correction information related to the combination, and as a result, even if the temperature of the differential amplifier circuit changes, the temperature change of the differential amplifier circuit can be prevented with a simple device configuration. By removing the detection error factors, it is possible to obtain a current detection value with high accuracy.
【００６２】さらに、請求項５の発明によれば、電圧信
号選択手段は、検出電圧差増幅手段から出力される差分
電圧信号と、複数の参照電圧増幅手段から各々出力され
る参照電圧信号とのうち、参照電圧信号を優先的に選択
出力するので、したがって、シャント抵抗の端子間電圧
差を表す差分電圧値の取り込みに優先して、差動増幅回
路の温度変化に起因する検出誤差の補正準備が推進され
ることとなり、結果として、高精度の電流検出値の取得
に寄与することができる。Further, according to the invention of claim 5, the voltage signal selecting means includes a difference voltage signal output from the detected voltage difference amplifying means and a reference voltage signal output from each of the plurality of reference voltage amplifying means. Among them, the reference voltage signal is preferentially selected and output, and therefore, the preparation for the correction of the detection error caused by the temperature change of the differential amplifier circuit is given priority over the acquisition of the differential voltage value indicating the voltage difference between the terminals of the shunt resistor. Is promoted, and as a result, it is possible to contribute to acquisition of a highly accurate current detection value.
【００６３】そして、請求項６の発明によれば、過電流
遮断制御手段は、検出電流補正手段で演算された電流値
と、所定の電流値とを比較参照して、負荷回路に所定の
電流値を越える過電流が流れているか否かを判定すると
ともに、この判定結果に基づいて、負荷回路における過
電流の供給を遮断制御するので、この結果、検出電流補
正手段で得られた高精度の電流検出値に基づいて、きわ
めて緻密な過電流供給遮断制御を実現することができる
というきわめて優れた効果を奏する。According to the sixth aspect of the invention, the overcurrent interruption control means compares the current value calculated by the detected current correction means with a predetermined current value and refers to the predetermined current value in the load circuit. It is determined whether or not an overcurrent exceeding a value is flowing, and the overcurrent supply in the load circuit is controlled to be cut off based on this determination result. As a result, the high accuracy obtained by the detected current correction means is obtained. It is possible to realize an extremely precise overcurrent supply cutoff control based on the detected current value.
【図１】図１は、本発明に係る電流検出装置を示す概略
ブロック構成図である。FIG. 1 is a schematic block configuration diagram showing a current detection device according to the present invention.
【図２】図２は、本発明に係る電流検出装置の主要部を
示す概略ブロック構成図である。FIG. 2 is a schematic block configuration diagram showing a main part of a current detection device according to the present invention.
【図３】図３（ａ），（ｂ），（ｃ）は、本発明に係る
電流検出装置の動作フローチャート図である。3 (a), (b), and (c) are operation flowcharts of the current detection device according to the present invention.
【図４】図４は、本発明に係る電流検出装置の動作説明
に供するタイムチャート図である。FIG. 4 is a time chart diagram for explaining the operation of the current detection device according to the present invention.
【図５】図５は、従来例に係る電流検出装置を示す概略
ブロック構成図である。FIG. 5 is a schematic block configuration diagram showing a current detection device according to a conventional example.
【図６】図６は、従来例に係る不具合の説明に供する図
である。FIG. 6 is a diagram for explaining a defect in the conventional example.
１ 電流検出装置 ３ 直流電源 ５ 負荷 ７ シャント抵抗 ９ ＭＯＳ型ＦＥＴ １３ 差動増幅回路（ＡＳＩＣ） １５ Ａ／Ｄ変換回路 １７ ＥＣＵ １９ Ｄ／Ａ変換回路 ２１ 指令制御部 ２３ 参照電圧記憶部 ２５ 補正情報記憶部 ２７ 検出電流補正部 ２９ 過電流判定部 ３５，３７，３９ 第１乃至第３のマルチプレクサ ４１ 論理和回路 ４３ コントローラ ＡＭＰ１ 第１の差動増幅器 ＡＭＰ２ 第２の差動増幅器 ＡＭＰ３ 第３の差動増幅器 ＡＭＰ４ 第４の差動増幅器 1 Current detector 3 DC power supply 5 load 7 Shunt resistance 9 MOS type FET 13 Differential amplifier circuit (ASIC) 15 A / D conversion circuit 17 ECU 19 D / A conversion circuit 21 Command controller 23 Reference voltage storage unit 25 Correction information storage unit 27 Detection current correction unit 29 Overcurrent determination unit 35, 37, 39 First to third multiplexers 41 OR circuit 43 controller AMP1 First differential amplifier AMP2 second differential amplifier AMP3 Third differential amplifier AMP4 Fourth differential amplifier
フロントページの続き (56)参考文献 特開 平４−96618（ＪＰ，Ａ) 特開 平５−203459（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01R 19/00 - 19/32 H03F 1/30 Continuation of front page (56) Reference JP-A-4-96618 (JP, A) JP-A-5-203459 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) G01R 19 / 00-19/32 H03F 1/30
Claims (6)
荷回路に流れる電流値を、当該負荷回路に直列に挿入接
続されたシャント抵抗の端子間電圧差から検出する如く
構成された電流検出装置であって、 前記シャント抵抗の端子間電圧差を増幅してアナログ形
態の差分電圧信号として出力する検出電圧差増幅手段
と、 相互に値が異なる複数の参照電圧をそれぞれ増幅してア
ナログ形態の参照電圧信号として各々出力する複数の参
照電圧増幅手段と、 前記検出電圧差増幅手段から出力される差分電圧信号
と、前記複数の参照電圧増幅手段から各々出力される複
数の参照電圧信号とのうち、いずれか１つの電圧信号を
予め決められている優先度に基づいて順次選択出力する
電圧信号選択手段と、 を含んで構成される差動増幅回路と、 当該差動増幅回路から入力したアナログ形態の電圧信号
を、ディジタル形態の電圧信号に変換して出力するＡ／
Ｄ変換回路と、 当該Ａ／Ｄ変換回路から入力した電圧信号のうち、複数
の参照電圧値をそれぞれ更新記憶する参照電圧記憶手段
と、 前記複数の参照電圧値の組み合わせ変数に関連付けて、
前記差動増幅回路の温度変化に起因する検出誤差を補正
する際に用いられる補正情報を記憶する補正情報記憶手
段と、 前記Ａ／Ｄ変換回路から前記シャント抵抗の端子間電圧
差を表す差分電圧値が入力されたとき、当該入力された
差分電圧値に内包されている、前記差動増幅回路の温度
変化に起因する検出誤差を、前記複数の参照電圧値の組
み合わせ変数に関連付けて記憶された補正情報のうち、
前記参照電圧記憶手段に更新記憶されている複数の参照
電圧値の組み合わせに係る補正情報を用いて補正すると
ともに、当該補正後の差分電圧値と、前記シャント抵抗
の抵抗値とを参照して、前記負荷回路に流れる電流値を
演算する検出電流補正手段と、 を備え、 前記差動増幅回路のうち、少なくとも前記検出電圧差増
幅手段及び前記複数の参照電圧増幅手段は、参照電圧を
直接補正用の電圧値として利用するために相互に熱結合
されてほぼ共通の温度環境となる如く集積させて設けら
れることを特徴とする電流検出装置。1. A current detector configured to detect a current value flowing in a load circuit configured by connecting a load to a DC power source, from a voltage difference between terminals of a shunt resistor inserted and connected in series to the load circuit. A detection voltage difference amplifying means for amplifying a voltage difference between terminals of the shunt resistor and outputting it as a differential voltage signal in an analog form; Of a plurality of reference voltage amplification means each outputting as a reference voltage signal, a difference voltage signal output from the detection voltage difference amplification means, and a plurality of reference voltage signals output from each of the plurality of reference voltage amplification means , One of the voltage signals
A differential amplifier circuit configured to include a voltage signal selection unit that sequentially selects and outputs based on a predetermined priority , and an analog voltage signal input from the differential amplifier circuit, in a digital form. A / convert to voltage signal and output
A D conversion circuit, reference voltage storage means for updating and storing a plurality of reference voltage values of the voltage signal input from the A / D conversion circuit, and a combination variable of the plurality of reference voltage values,
Correction information storage means for storing correction information used when correcting a detection error caused by a temperature change of the differential amplifier circuit; and a differential voltage representing a voltage difference between the terminals of the shunt resistor from the A / D conversion circuit. When a value is input, a detection error caused by a temperature change of the differential amplifier circuit, which is included in the input differential voltage value, is stored in association with a combination variable of the plurality of reference voltage values. Of the correction information,
The correction is performed using the correction information related to the combination of the plurality of reference voltage values updated and stored in the reference voltage storage unit, and the corrected differential voltage value and the resistance value of the shunt resistor are referred to, and a detected current correcting means for calculating a value of current flowing in the load circuit, of the differential amplifier circuit, at least the detected voltage difference amplifying means and the plurality of reference voltage amplifying means, the reference voltage
A current detecting device, which is thermally integrated with each other so as to be directly used as a voltage value for correction, and is integrated so as to have a substantially common temperature environment.
に流れる電流値が零時におけるオフセット電圧値と、前
記負荷回路に流れる電流値が飽和時における飽和電圧値
との両者、又は少なくともいずれか一方を含むことを特
徴とする請求項１に記載の電流検出装置。2. The plurality of reference voltage values are both an offset voltage value when a current value flowing in the load circuit is zero and a saturation voltage value when a current value flowing in the load circuit is saturated, or at least one of them. The current detection device according to claim 1, wherein the current detection device includes one or the other.
に流れる電流値が零時におけるオフセット電圧値と、前
記負荷回路に流れる電流値が飽和時における飽和電圧値
との間の電圧値となることを妨げないことを特徴とする
請求項２に記載の電流検出装置。3. The plurality of reference voltage values are voltage values between an offset voltage value when a current value flowing in the load circuit is zero and a saturation voltage value when a current value flowing in the load circuit is saturated. The current detection device according to claim 2, wherein the current detection device does not interfere with the above.
差増幅手段から出力される差分電圧信号と、前記複数の
参照電圧増幅手段から各々出力される参照電圧信号と
を、所定時間以内に全て選択出力することを特徴とする
請求項１に記載の電流検出装置。4. The voltage signal selecting means outputs all of the differential voltage signal output from the detected voltage difference amplifying means and the reference voltage signal output from each of the plurality of reference voltage amplifying means within a predetermined time. The current detection device according to claim 1, wherein the current detection device selectively outputs the current.
差増幅手段から出力される差分電圧信号と、前記複数の
参照電圧増幅手段から各々出力される参照電圧信号との
うち、参照電圧信号を優先的に選択出力することを特徴
とする請求項１又は４に記載の電流検出装置。5. The voltage signal selection means selects a reference voltage signal from among the differential voltage signal output from the detected voltage difference amplification means and the reference voltage signal output from each of the plurality of reference voltage amplification means. The current detection device according to claim 1 or 4, wherein the selective output is performed with priority.
値と、所定の電流値とを比較参照して、前記負荷回路に
当該所定の電流値を越える過電流が流れているか否かを
判定するとともに、当該判定結果に基づいて、前記負荷
回路における過電流の供給を遮断制御する過電流遮断制
御手段をさらに備えて構成されることを特徴とする請求
項１乃至５に記載の電流検出装置。6. The current value calculated by the detected current correction means is compared with a predetermined current value to determine whether or not an overcurrent exceeding the predetermined current value is flowing through the load circuit. The current detection device according to claim 1, further comprising an overcurrent cutoff control unit that cuts off an overcurrent supply in the load circuit based on the determination result. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09356998A JP3454708B2 (en) | 1998-04-06 | 1998-04-06 | Current detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09356998A JP3454708B2 (en) | 1998-04-06 | 1998-04-06 | Current detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11295354A JPH11295354A (en) | 1999-10-29 |
| JP3454708B2 true JP3454708B2 (en) | 2003-10-06 |
Family
ID=14085896
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09356998A Expired - Fee Related JP3454708B2 (en) | 1998-04-06 | 1998-04-06 | Current detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3454708B2 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6927599B2 (en) | 2003-11-24 | 2005-08-09 | Fairchild Semiconductor Corporation | Failsafe for differential circuit based on current sense scheme |
| JP4556754B2 (en) * | 2005-04-20 | 2010-10-06 | 株式会社デンソー | Inductive load drive |
| DE102006001874B4 (en) * | 2006-01-13 | 2012-05-24 | Infineon Technologies Ag | Method and device for current and temperature measurement in a power electronic circuit |
| JP5188465B2 (en) * | 2009-06-30 | 2013-04-24 | 日立オートモティブシステムズ株式会社 | Current detection device and control system using the same |
| JP5509943B2 (en) * | 2010-03-11 | 2014-06-04 | 富士電機株式会社 | Current output device |
| JP2017161409A (en) * | 2016-03-10 | 2017-09-14 | 住友電気工業株式会社 | Voltage detector, current detector, and computer program |
-
1998
- 1998-04-06 JP JP09356998A patent/JP3454708B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11295354A (en) | 1999-10-29 |
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