JPH0956057A - Constant current circuit protector - Google Patents
Constant current circuit protectorInfo
- Publication number
- JPH0956057A JPH0956057A JP7226988A JP22698895A JPH0956057A JP H0956057 A JPH0956057 A JP H0956057A JP 7226988 A JP7226988 A JP 7226988A JP 22698895 A JP22698895 A JP 22698895A JP H0956057 A JPH0956057 A JP H0956057A
- Authority
- JP
- Japan
- Prior art keywords
- constant current
- voltage
- load
- terminal
- comparator
- 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.)
- Pending
Links
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Protection Of Static Devices (AREA)
Abstract
(57)【要約】
【課題】簡単な回路によって駆動負荷を保護する。
【解決手段】ホール素子等の駆動負荷１の一方の端子は
抵抗２を介してグランドに接続され、他方の端子は定電
流駆動ドライバー３の出力端子に接続されている。抵抗
２と駆動負荷１との接続点は比較器４の＋入力端子に接
続されている。比較器４の−入力端子は基準電圧源５の
＋端子に接続され、比較器４の出力端子は定電流駆動ド
ライバー３の制御入力端子に接続されている。駆動負荷
１にはその最大定格以下の降伏電圧を有するツェナーダ
イオード６が並列に接続されている。
(57) Abstract: A drive load is protected by a simple circuit. SOLUTION: One terminal of a driving load 1 such as a Hall element is connected to a ground via a resistor 2, and the other terminal is connected to an output terminal of a constant current driving driver 3. The connection point between the resistor 2 and the driving load 1 is connected to the + input terminal of the comparator 4. The-input terminal of the comparator 4 is connected to the + terminal of the reference voltage source 5, and the output terminal of the comparator 4 is connected to the control input terminal of the constant current drive driver 3. The driving load 1 is connected in parallel with a Zener diode 6 having a breakdown voltage equal to or lower than its maximum rating.
Description
【０００１】[0001]
【発明の属する技術分野】本発明はホール素子等の駆動
負荷に定電流を供給する定電流回路に関わり、特に、そ
の駆動負荷の保護装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant current circuit for supplying a constant current to a drive load such as a Hall element, and more particularly to a protection device for the drive load.
【０００２】[0002]
【従来の技術】ホール素子等の駆動負荷に定電流を供給
する場合、温度上昇等により素子の抵抗値が上昇し、印
加電圧が最大定格を越えることがある。この場合定電流
を供給する回路の最大供給電圧が駆動負荷の最大定格以
下であれば問題ないが、最大定格を越えるときは駆動負
荷を保護するための対策が必要となる。このように駆動
負荷を保護するため、従来、駆動負荷の印加電圧を検出
し、その検出電圧によって印加電圧を押さえるための保
護手段を設けていた。2. Description of the Related Art When a constant current is supplied to a drive load such as a Hall element, the resistance value of the element increases due to temperature rise and the applied voltage may exceed the maximum rating. In this case, there is no problem if the maximum supply voltage of the circuit that supplies the constant current is equal to or lower than the maximum rating of the driving load, but if it exceeds the maximum rating, measures for protecting the driving load are required. In order to protect the drive load in this way, conventionally, a protection means for detecting the applied voltage of the drive load and suppressing the applied voltage by the detected voltage has been provided.
【０００３】[0003]
【発明が解決しようとする課題】上記した従来の定電流
回路の駆動負荷の保護方法によると、駆動負荷の印加電
圧の検出回路や検出回路の出力信号により定電流回路を
保護する制御回路が必要となり、回路構成が複雑かつ高
価なものとなる。According to the above-mentioned conventional method for protecting the constant current circuit drive load, a detection circuit for the applied voltage of the drive load and a control circuit for protecting the constant current circuit by the output signal of the detection circuit are required. Therefore, the circuit configuration becomes complicated and expensive.
【０００４】本発明は上記した点に鑑みてなされたもの
であって、その目的とするところは、簡単な回路によっ
て駆動負荷を保護することができる定電流回路の保護装
置を提供することである。The present invention has been made in view of the above points, and an object thereof is to provide a protection device for a constant current circuit capable of protecting a drive load with a simple circuit. .
【０００５】[0005]
【課題を解決するための手段】本発明の定電流回路の保
護装置は、駆動負荷と抵抗との直列回路に電圧を印加
し、前記抵抗に現れる電圧を一定とするように前記電圧
を制御して駆動負荷に定電流を供給する定電流回路にお
いて、前記駆動負荷に駆動負荷の最大定格以下の降伏電
圧を有するツェナーダイオードを並列に接続したもので
ある。A protective device for a constant current circuit according to the present invention applies a voltage to a series circuit of a driving load and a resistor and controls the voltage so that the voltage appearing at the resistor is constant. In a constant current circuit for supplying a constant current to a driving load, a zener diode having a breakdown voltage equal to or lower than the maximum rating of the driving load is connected in parallel to the driving load.
【０００６】このような構成において、駆動負荷の抵抗
値が増大しその印加電圧がツェナーダイオードの降伏電
圧を越えると、ツェナーダイオードに大きい電流が流れ
前記直列回路の抵抗に現れる電圧が大きくなり直列回路
に印加される電圧が減少するように制御される。駆動負
荷の最大定格はツェナーダイオードの降伏電圧より大き
いから駆動負荷に最大定格を越える電圧が印加されるこ
とを防止できる。In such a configuration, when the resistance value of the driving load increases and the applied voltage exceeds the breakdown voltage of the Zener diode, a large current flows through the Zener diode and the voltage appearing in the resistance of the series circuit increases, and the series circuit increases. The voltage applied to is controlled to decrease. Since the maximum rating of the driving load is higher than the breakdown voltage of the Zener diode, it is possible to prevent a voltage exceeding the maximum rating from being applied to the driving load.
【０００７】[0007]
【発明の実施の形態】以下、本発明を適用した定電流回
路の保護装置を図１を参照して説明する。図において、
１はホール素子等の駆動負荷であり、その一方の端子は
抵抗２を介してグランドに接続され、他方の端子は定電
流駆動ドライバー３の出力端子に接続されている。BEST MODE FOR CARRYING OUT THE INVENTION A protective device for a constant current circuit to which the present invention is applied will be described below with reference to FIG. In the figure,
Reference numeral 1 denotes a driving load such as a Hall element, one terminal of which is connected to the ground via a resistor 2 and the other terminal is connected to an output terminal of a constant current driving driver 3.
【０００８】抵抗２と駆動負荷１との接続点は比較器４
の＋入力端子に接続されている。比較器４の−入力端子
は基準電圧源５の＋端子に接続され、比較器４の出力端
子は定電流駆動ドライバー３の制御入力端子に接続され
ている。さらに、駆動負荷１にはその最大定格以下の降
伏電圧を有するツェナーダイオード６が並列に接続され
ている。The connection point between the resistor 2 and the driving load 1 is the comparator 4
Is connected to the + input terminal of. The-input terminal of the comparator 4 is connected to the + terminal of the reference voltage source 5, and the output terminal of the comparator 4 is connected to the control input terminal of the constant current drive driver 3. Further, a zener diode 6 having a breakdown voltage equal to or lower than the maximum rating is connected to the driving load 1 in parallel.
【０００９】上記構成において、駆動負荷１に印加され
る電圧がツェナーダイオード６の降伏電圧以下の場合に
はツェナーダイオード６に電流が流れず、駆動負荷に流
れる電流はすべて抵抗２に流れ駆動負荷１の電流に比例
する電圧Ｖｘが駆動負荷１と抵抗２の接続点に現れる。
電圧Ｖｘと定電圧源５の電圧Ｖref とが比較器４で比較
され、Ｖｘ＞Ｖref のときは比較器４はＨレベル信号を
出力する。定電流駆動ドライバー３は比較器４からのＨ
レベル信号を受けて、印加電圧Ｖy を減少させる。In the above structure, when the voltage applied to the driving load 1 is equal to or lower than the breakdown voltage of the Zener diode 6, no current flows through the Zener diode 6, and all the current flowing through the driving load flows through the resistor 2 and the driving load 1 The voltage V x proportional to the current of appears at the connection point between the driving load 1 and the resistor 2.
The voltage V x and the voltage V ref of the constant voltage source 5 are compared by the comparator 4, and when V x > V ref , the comparator 4 outputs an H level signal. The constant current drive driver 3 is the H from the comparator 4.
Upon receiving the level signal, the applied voltage V y is reduced.
【００１０】Ｖｘ＜Ｖref のときは比較器４はＬレベル
信号を出力する。定電流駆動ドライバー３は比較器４か
らのＬレベル信号を受けて、印加電圧Ｖy を増大させ
る。このようにして電圧Ｖｘが一定となるように印加電
圧Ｖy が制御されて駆動負荷１に一定電流が供給され
る。駆動負荷１の抵抗が異常に高くなると、ツェナーダ
イオード６に印加される電圧Ｖz がツェナーダイオード
６の降伏電圧を越えるようになり、ツェナーダイオード
６に大きい電流が流れる。When V x <V ref , the comparator 4 outputs an L level signal. The constant current drive driver 3 receives the L level signal from the comparator 4 and increases the applied voltage V y . In this way, the applied voltage V y is controlled so that the voltage V x becomes constant, and a constant current is supplied to the drive load 1. When the resistance of the driving load 1 becomes abnormally high, the voltage V z applied to the Zener diode 6 exceeds the breakdown voltage of the Zener diode 6, and a large current flows through the Zener diode 6.
【００１１】すると、電圧Ｖｘが増大し、Ｖｘ＞Ｖref
となり比較器４はＨレベル信号を出力する。そして、定
電流駆動ドライバー３は比較器４からのＨレベル信号を
受けて、印加電圧Ｖy を減少させる。このようにして、
駆動負荷１にツェナーダイオード６の降伏電圧を大きく
こえる電圧が印加されることがなくなり、駆動負荷１に
最大定格を越える電圧を印加されることが防止される。Then, the voltage V x increases and V x > V ref
The comparator 4 outputs an H level signal. Then, the constant current drive driver 3 receives the H level signal from the comparator 4 and reduces the applied voltage V y . In this way,
The drive load 1 is prevented from being applied with a voltage exceeding the breakdown voltage of the Zener diode 6, and the drive load 1 is prevented from being applied with a voltage exceeding the maximum rating.
【００１２】[0012]
【発明の効果】以上説明したように、本発明の定電流回
路の保護装置によると、簡単な回路によって駆動負荷を
保護することができるAs described above, according to the protection device for a constant current circuit of the present invention, the drive load can be protected by a simple circuit.
【図１】本発明を適用した定電流回路の保護装置を示す
回路図である。FIG. 1 is a circuit diagram showing a protection device for a constant current circuit to which the present invention is applied.
１ 駆動負荷 ２ 抵抗 ３ 定電流駆動ドライバー ４ 比較器 ５ 基準電圧源 ６ ツェナーダイオード 1 Drive load 2 Resistance 3 Constant current drive driver 4 Comparator 5 Reference voltage source 6 Zener diode
Claims (1)
加し、前記抵抗に現れる電圧を一定とするように前記電
圧を制御して駆動負荷に定電流を供給する定電流回路に
おいて、前記駆動負荷に駆動負荷の最大定格以下の降伏
電圧を有するツェナーダイオードを並列に接続したこと
を特徴とする定電流回路の保護装置。1. A constant current circuit for supplying a constant current to a drive load by applying a voltage to a series circuit of a drive load and a resistor and controlling the voltage so that a voltage appearing at the resistor is constant. A protective device for a constant current circuit, wherein a zener diode having a breakdown voltage equal to or lower than the maximum rating of the driving load is connected in parallel to the driving load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7226988A JPH0956057A (en) | 1995-08-14 | 1995-08-14 | Constant current circuit protector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7226988A JPH0956057A (en) | 1995-08-14 | 1995-08-14 | Constant current circuit protector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0956057A true JPH0956057A (en) | 1997-02-25 |
Family
ID=16853753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7226988A Pending JPH0956057A (en) | 1995-08-14 | 1995-08-14 | Constant current circuit protector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0956057A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008152978A1 (en) * | 2007-06-11 | 2008-12-18 | Sanken Electric Co., Ltd. | Multi-output switching power supply device |
-
1995
- 1995-08-14 JP JP7226988A patent/JPH0956057A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008152978A1 (en) * | 2007-06-11 | 2008-12-18 | Sanken Electric Co., Ltd. | Multi-output switching power supply device |
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Legal Events
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Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
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| R350 | Written notification of registration of transfer |
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