JP2007004472A

JP2007004472A - Hysteresis circuit and power supply circuit

Info

Publication number: JP2007004472A
Application number: JP2005183767A
Authority: JP
Inventors: Naonori Matsumoto; 尚能松本; Makoto Sakano; 誠坂野
Original assignee: Toyota Industries Corp
Current assignee: Toyota Industries Corp
Priority date: 2005-06-23
Filing date: 2005-06-23
Publication date: 2007-01-11
Anticipated expiration: 2025-06-23
Also published as: JP4534879B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hysteresis circuit that requires no power supply, and a power supply circuit that uses the hysteresis circuit. <P>SOLUTION: The hysteresis circuit includes zener diodes 2, 3 connected in series between an input terminal 10 and an input terminal 11; an FET 4 provided between the input terminal 11 and an output terminal 12 and which is turned on when the total voltage of voltages applied to the zener diodes 2, 3 exceeds a first predetermined voltage, outputs the voltage of the negative input terminal 11 from the output terminal 12; and a photocoupler 7 connected in parallel with the zener diode 2 and which applies the total voltage to the zener diode 3 when the FET 4 is turned on. After the FET 4 is turned on, when the voltage applied to the zener diode 3 becomes lower than a second predetermined voltage smaller than the first predetermined voltage, the FET 4 is turned off and the voltage outputted from the output terminal 12 is switched to the voltage of the positive input terminal 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、ヒステリシス回路及びそのヒステリシス回路を用いた電源回路に関する。 The present invention relates to a hysteresis circuit and a power supply circuit using the hysteresis circuit.

ヒステリシス回路は、入力電圧が閾値より高くなったり低くなったりすると、出力電圧を変化させたり元に戻したりする回路であり、出力電圧を変化させるための閾値と変化した出力電圧を元に戻すための閾値とを異ならせている。例えば、コンパレータの出力端子とそのコンパレータのプラスの入力端子とを抵抗を介して接続することによりヒステリシス回路を構成しているものがある（例えば、特許文献１参照）。 The hysteresis circuit is a circuit that changes or restores the output voltage when the input voltage becomes higher or lower than the threshold value. In order to restore the threshold value for changing the output voltage and the changed output voltage. The threshold value is different. For example, a hysteresis circuit is configured by connecting an output terminal of a comparator and a positive input terminal of the comparator via a resistor (see, for example, Patent Document 1).

このように、ヒステリシス回路は、出力電圧を変化させるための閾値と変化した出力電圧を元に戻すための閾値とを異ならせているため、例えば、入力電圧にノイズが含まれ入力電圧が多少変動していても、そのノイズの振幅が出力電圧を変化させるための閾値と変化した出力電圧を元に戻すための閾値との間に収まっていれば、ノイズの影響を抑えて出力電圧を出力することができる。
特開２００１−１４８６２１号公報（第３〜９頁、第１〜５図） In this way, the hysteresis circuit has a different threshold value for changing the output voltage and a threshold value for restoring the changed output voltage. For example, the input voltage includes noise and the input voltage varies slightly. If the amplitude of the noise is between the threshold for changing the output voltage and the threshold for returning the changed output voltage, the output voltage is output while suppressing the influence of noise. be able to.
JP 2001-148621 A (pages 3 to 9, FIGS. 1 to 5)

しかしながら、コンパレータを用いてヒステリシス回路を構成する場合では、コンパレータを動かすための電源が必要であり、電源のない回路内にコンパレータを用いたヒステリシス回路を設けようとする場合、そのコンパレータを動かすための電源を別に用意する必要があり、その分回路規模やコストが増大するという問題がある。 However, when a hysteresis circuit is configured using a comparator, a power source for moving the comparator is required. When a hysteresis circuit using a comparator is provided in a circuit without a power source, There is a problem that it is necessary to prepare a power supply separately, and the circuit scale and cost increase accordingly.

そこで、本発明では、電源を必要としないヒステリシス回路及びそのヒステリシス回路を用いた電源回路を提供することを目的とする。 Therefore, an object of the present invention is to provide a hysteresis circuit that does not require a power supply and a power supply circuit using the hysteresis circuit.

上記の課題を解決するために本発明では、以下のような構成を採用した。
すなわち、本発明のヒステリシス回路は、互いに直列接続される第１及び第２の素子と、前記第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧より高くなると、オンし出力端子の電位を第１の電位から第２の電位に切り替える切替スイッチング素子と、前記第１及び第２の素子のうちの一方の素子に受光素子が並列に接続され、前記切替スイッチング素子がオンすると、発光素子が発光し前記合計電圧を前記第１及び第２の素子のうちの他方の素子に印加させるフォトカプラとを備え、前記切替スイッチング素子がオンした後、前記他方の素子に印加される電圧が前記第１の所定電圧よりも小さい第２の所定電圧より低くなると、前記切替スイッチング素子がオフし前記出力端子の電位が前記第２の電位から前記第１の電位に切り替わることを特徴とする。 In order to solve the above problems, the present invention adopts the following configuration.
That is, in the hysteresis circuit of the present invention, when the total voltage of the first and second elements connected in series with each other and the voltage applied to each of the first and second elements is higher than the first predetermined voltage, A switching switching element that turns on and switches the potential of the output terminal from the first potential to the second potential; and a light receiving element connected in parallel to one of the first and second elements, and the switching switching element Is turned on, a light-emitting element emits light, and a photocoupler that applies the total voltage to the other element of the first and second elements. After the switching element is turned on, the other element When the applied voltage becomes lower than a second predetermined voltage that is lower than the first predetermined voltage, the switching element is turned off, and the potential of the output terminal is changed from the second potential to the first potential. Wherein the switch to the potential.

このように、第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧よりも高くなると、出力端子の電位を第１の電位から第２の電位に切り替え、さらに第１及び第２の素子のうちフォトカプラの受光素子に接続されない方の素子に印加される電圧が第１の所定電圧よりも小さい第２の所定電圧よりも低くなると、出力端子の電位を第２の電位から第１の電位に切り替えるので、出力端子の電位を第１の電位から第２の電位に切り替えるための閾値である第１の所定電圧と、出力端子の電位を第２の電位から第１の電位に切り替えるための閾値である第２の所定電圧とを異ならせることができる。これにより、コンパレータを用いることなく出力電圧を変化させるための閾値と変化した出力電圧を元に戻すための閾値とを異ならせることができるので、コンパレータのように電源を別に用意することなくヒステリシス回路を構成することができる。 Thus, when the total voltage applied to each of the first and second elements becomes higher than the first predetermined voltage, the potential of the output terminal is switched from the first potential to the second potential. When the voltage applied to the element that is not connected to the light receiving element of the photocoupler among the first and second elements becomes lower than a second predetermined voltage that is smaller than the first predetermined voltage, the potential of the output terminal is set to the second potential. Is switched from the first potential to the first potential, the first predetermined voltage which is a threshold for switching the potential of the output terminal from the first potential to the second potential, and the potential of the output terminal from the second potential to the first potential. The second predetermined voltage which is a threshold value for switching to the potential of 1 can be made different. As a result, the threshold for changing the output voltage without using a comparator can be made different from the threshold for returning the changed output voltage, so that a hysteresis circuit can be used without preparing a separate power supply like a comparator. Can be configured.

また、本発明のヒステリシス回路は、プラスの入力端子とマイナスの入力端子との間に互いに直列接続されて設けられる第１及び第２の素子と、前記マイナスの入力端子と出力端子との間に設けられ、前記第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧より高くなると、オンし前記出力端子の電位をある電位から前記マイナスの入力端子の電位に切り替える切替スイッチング素子と、前記第１及び第２の素子のうちの一方の素子に受光素子が並列に接続され、前記切替スイッチング素子がオンすると、発光素子が発光し前記合計電圧を前記第１及び第２の素子のうちの他方の素子に印加させるフォトカプラとを備え、前記切替スイッチング素子がオンした後、前記他方の素子に印加される電圧が前記第１の所定電圧よりも小さい第２の所定電圧より低くなると、前記切替スイッチング素子がオフし前記出力端子の電位が前記マイナスの入力端子の電位から前記ある電位に切り替わることを特徴とする。 The hysteresis circuit of the present invention includes a first element and a second element connected in series between a positive input terminal and a negative input terminal, and between the negative input terminal and the output terminal. When the total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage, the output terminal is turned on and the potential of the output terminal is switched from a certain potential to the potential of the negative input terminal. When a light receiving element is connected in parallel to the switching switching element and one of the first and second elements, and the switching switching element is turned on, the light emitting element emits light, and the total voltage is set to the first and second elements. A photocoupler applied to the other of the two elements, and after the switching switching element is turned on, a voltage applied to the other element is the first predetermined voltage. Becomes lower than the smaller second predetermined voltage than the switching switching elements, characterized in that the potential of off and the output terminal switches to the certain potential from the potential of the negative input terminal.

また、本発明のヒステリシス回路は、プラスの入力端子とマイナスの入力端子との間に互いに直列接続されて設けられる第１及び第２の素子と、前記マイナスの入力端子と出力端子との間に設けられ、前記第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧より高くなると、オンし前記出力端子の電位をある電位から前記マイナスの入力端子の電位に切り替える切替スイッチング素子と、前記プラスの入力端子と前記切替スイッチング素子との間に発光素子が設けられ、前記第１及び第２の素子のうち前記プラスの入力端子側に設けられる第１の素子に受光素子が並列に接続され、前記切替スイッチング素子がオンすると、前記発光素子が発光し前記合計電圧を前記第２の素子に印加させるフォトカプラとを備え、前記切替スイッチング素子がオンした後、前記第２の素子に印加される電圧が前記第１の所定電圧よりも小さい第２の所定電圧より低くなると、前記切替スイッチング素子がオフし前記出力端子の電位が前記マイナスの入力端子の電位から前記ある電位に切り替わることを特徴とする。 The hysteresis circuit of the present invention includes a first element and a second element connected in series between a positive input terminal and a negative input terminal, and between the negative input terminal and the output terminal. When the total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage, the output terminal is turned on and the potential of the output terminal is switched from a certain potential to the potential of the negative input terminal. A light emitting element is provided between the switching switching element and the positive input terminal and the switching switching element, and light is received by the first element provided on the positive input terminal side of the first and second elements. And a photocoupler that causes the light emitting element to emit light and apply the total voltage to the second element when the switching switching element is turned on. After the switching switching element is turned on, when the voltage applied to the second element becomes lower than a second predetermined voltage that is smaller than the first predetermined voltage, the switching switching element is turned off and the potential of the output terminal becomes The potential of the negative input terminal is switched to the certain potential.

なお、上記ある電位は、マイナスの入力端子の電位以外の電位とする。
また、前記第１及び第２の素子を、それぞれ、ツェナーダイオードとし、前記第１の所定電圧を、前記第１及び第２の素子のそれぞれの降伏電圧の合計電圧とし、前記第２の所定電圧を、前記第１及び第２の素子のうち前記受光素子に接続されない方の素子の降伏電圧としてもよい。 Note that the certain potential is a potential other than the potential of the negative input terminal.
Further, each of the first and second elements is a Zener diode, the first predetermined voltage is a total voltage of the breakdown voltages of the first and second elements, and the second predetermined voltage. May be the breakdown voltage of the element that is not connected to the light receiving element among the first and second elements.

また、前記第１及び第２の素子を、それぞれ、抵抗とし、前記第１及び第２の素子と直列に分圧用抵抗を接続し、前記第１の所定電圧を、前記切替スイッチング素子がオンするとき、前記第１及び第２の素子と前記分圧用抵抗とにより分圧される電圧とし、前記第２の所定電圧を、前記切替スイッチング素子がオフするとき、前記第１及び第２の素子のうち前記受光素子に接続されない方の素子と前記分圧電圧とにより分圧される電圧としてもよい。 Further, the first and second elements are resistors, respectively, a voltage dividing resistor is connected in series with the first and second elements, and the switching switching element turns on the first predetermined voltage. A voltage divided by the first and second elements and the voltage dividing resistor, and when the switching element is turned off, the second predetermined voltage is applied to the first and second elements. Of these, a voltage divided by the element not connected to the light receiving element and the divided voltage may be used.

また、本発明の電源回路は、電源とＧＮＤとの間に互いに直列接続されて設けられる第１及び第２の素子と、前記第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧より高くなると、オンする切替スイッチング素子と、前記切替スイッチング素子がオンすると、前記電源と負荷とをつなぐ経路を遮断させる遮断スイッチング素子と、前記第１及び第２の素子のうちの一方の素子に受光素子が並列に接続され、前記切替スイッチング素子がオンすると、発光素子が発光し前記合計電圧を前記第１及び第２の素子のうちの他方の素子にも印加させるフォトカプラとを備え、前記切替スイッチング素子がオンした後、前記他方の素子に印加される電圧が前記第１の所定電圧よりも小さい第２の所定電圧より低くなると、前記切替スイッチング素子がオフすると共に前記遮断スイッチング素子がオンし前記電源と前記負荷とをつなぐ経路の遮断が復帰することを特徴とする。 In the power supply circuit of the present invention, the total voltage of the first and second elements provided in series with each other between the power supply and GND and the voltage applied to each of the first and second elements is A switching switching element that is turned on when higher than a first predetermined voltage, a cutoff switching element that shuts off a path connecting the power source and the load when the switching switching element is turned on, and the first and second elements, When a light receiving element is connected in parallel to one of the elements and the switching switching element is turned on, the light emitting element emits light, and the total voltage is applied to the other element of the first and second elements. And after the switching switching element is turned on, when the voltage applied to the other element becomes lower than a second predetermined voltage smaller than the first predetermined voltage, Blocking of the blocking switching element is turned on connecting the said power source and the load path with exchange switching element is turned off, characterized in that the return.

これにより、第１及び第２の素子それぞれに印加される電圧の合計電圧が第１の所定電圧より高くなってからその合計電圧が第２の所定電圧より低くなるまで遮断スイッチング素子をオフさせ続けることができるので、合計電圧が多少変動しても遮断スイッチング素子のオン、オフを頻繁に行わせないようにすることができる。 As a result, after the total voltage applied to each of the first and second elements becomes higher than the first predetermined voltage, the cutoff switching element is kept off until the total voltage becomes lower than the second predetermined voltage. Therefore, it is possible to prevent the cutoff switching element from being frequently turned on and off even if the total voltage varies somewhat.

また、合計電圧が第１の所定電圧よりも小さい第２の所定電圧より低くなると、電源と負荷とをつなぐ経路の遮断を復帰させているので、例えば、電源と負荷との間にコイル及びコンデンサからなるフィルタ回路が設けられている場合、経路の遮断復帰後、そのフィルタ回路のコイルに流れる電流を抑えることができる。これにより、コイルの体格を小さくすることができフィルタ回路を小型化することができる。また、経路の遮断復帰後、遮断スイッチング素子に流れる電流を抑えることもできるので、その分許容電流の小さい安価な遮断スイッチング素子を使用することができ電源回路のコストを抑えることができる。 Further, when the total voltage becomes lower than the second predetermined voltage, which is smaller than the first predetermined voltage, the interruption of the path connecting the power source and the load is restored. For example, a coil and a capacitor between the power source and the load are restored. In the case where a filter circuit comprising: is provided, the current flowing through the coil of the filter circuit can be suppressed after the path is cut off and restored. Thereby, the physique of a coil can be made small and a filter circuit can be reduced in size. In addition, since the current flowing through the cutoff switching element can be suppressed after the path is cut off, an inexpensive cutoff switching element having a small allowable current can be used, and the cost of the power supply circuit can be suppressed.

本発明によれば、コンパレータのように電源を別に用意することなくヒステリシス回路を構成することができる。 According to the present invention, it is possible to configure a hysteresis circuit without preparing a separate power source like a comparator.

以下、本発明の実施形態を図面を用いて説明する。
図１は、本発明の実施形態のヒステリシス回路を示す図である。
図１に示すヒステリシス回路１は、ツェナーダイオード２（第１の素子）と、ツェナーダイオード３（第２の素子）と、ＮチャネルＭＯＳＦＥＴ（以下、ＦＥＴという）４（切替スイッチング素子）と、発光ダイオード５（発光素子）及び受光トランジスタ６（受光素子）からなるフォトカプラ７と、抵抗８（分圧用抵抗）と、抵抗９とを備えて構成されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a hysteresis circuit according to an embodiment of the present invention.
1 includes a Zener diode 2 (first element), a Zener diode 3 (second element), an N-channel MOSFET (hereinafter referred to as FET) 4 (switching switching element), and a light emitting diode. The photocoupler 7 includes 5 (light emitting element) and a light receiving transistor 6 (light receiving element), a resistor 8 (voltage dividing resistor), and a resistor 9.

すなわち、ツェナーダイオード２のカソードは、プラスの入力端子１０と接続され、ツェナーダイオード２のアノードは、ツェナーダイオード３のカソードと接続されている。また、ツェナーダイオード３のアノードは、抵抗８を介してマイナスの入力端子１１と接続されている。また、ＦＥＴ４のゲートは、ツェナーダイオード３のアノードと抵抗８との間に接続され、ＦＥＴ４のソースは、入力端子１１と接続され、ＦＥＴ４のドレインは、発光ダイオード５のカソードに接続されている。また、ＦＥＴ４のドレインと発光ダイオード５のカソードとの間には、出力端子１２が接続されている。また、発光ダイオード５のアノードは、抵抗９を介して入力端子１０と接続され、受光トランジスタ６のコレクタは、ツェナーダイオード２のカソードと接続され、受光トランジスタ６のエミッタは、ツェナーダイオード２のアノードと接続されている。 That is, the cathode of the Zener diode 2 is connected to the positive input terminal 10, and the anode of the Zener diode 2 is connected to the cathode of the Zener diode 3. The anode of the Zener diode 3 is connected to the negative input terminal 11 via the resistor 8. The gate of the FET 4 is connected between the anode of the Zener diode 3 and the resistor 8, the source of the FET 4 is connected to the input terminal 11, and the drain of the FET 4 is connected to the cathode of the light emitting diode 5. An output terminal 12 is connected between the drain of the FET 4 and the cathode of the light emitting diode 5. The anode of the light emitting diode 5 is connected to the input terminal 10 via the resistor 9, the collector of the light receiving transistor 6 is connected to the cathode of the Zener diode 2, and the emitter of the light receiving transistor 6 is connected to the anode of the Zener diode 2. It is connected.

次に、ヒステリシス回路１の動作について説明する。
まず、ツェナーダイオード２、３それぞれに印加される電圧の合計電圧（以下、入力電圧という）がツェナーダイオード２、３それぞれの降伏電圧の合計電圧（第１の所定電圧）より低い場合では、ツェナーダイオード２、３に電流が流れずＦＥＴ４のゲートに電圧が印加されないため、出力端子１２の電位はほぼ入力端子１０の電位（第１の電位）である。 Next, the operation of the hysteresis circuit 1 will be described.
First, in the case where the total voltage (hereinafter referred to as input voltage) applied to the Zener diodes 2 and 3 is lower than the total voltage (first predetermined voltage) of the breakdown voltages of the Zener diodes 2 and 3, respectively, Since no current flows through 2 and 3 and no voltage is applied to the gate of the FET 4, the potential of the output terminal 12 is substantially the potential of the input terminal 10 (first potential).

次に、入力電圧がツェナーダイオード２、３それぞれの降伏電圧の合計電圧より高くなると、ツェナーダイオード２、３それぞれに電流が流れＦＥＴ４のゲート電位がＦＥＴ４のオン電圧より高くなり、ＦＥＴ４がオンしＦＥＴ４のドレイン電位が入力端子１１の電位となり、出力端子１２の電位が入力端子１０の電位から入力端子１１の電位（第２の電位）に切り替わる。 Next, when the input voltage becomes higher than the total voltage of the breakdown voltages of the Zener diodes 2 and 3, current flows through the Zener diodes 2 and 3, the gate potential of the FET 4 becomes higher than the ON voltage of the FET 4, and the FET 4 is turned on. Becomes the potential of the input terminal 11, and the potential of the output terminal 12 is switched from the potential of the input terminal 10 to the potential of the input terminal 11 (second potential).

また、ＦＥＴ４がオンすると、発光ダイオード５に電流が流れ発光ダイオード５が発光し、受光トランジスタ６がオンする。そして、受光トランジスタ６がオンすると、受光トランジスタ６のコレクタ電位がエミッタ電位とほぼ同電位となり、入力電圧とほぼ同じ電圧がツェナーダイオード３に印加されるようになる。 When the FET 4 is turned on, a current flows through the light emitting diode 5 and the light emitting diode 5 emits light, and the light receiving transistor 6 is turned on. When the light receiving transistor 6 is turned on, the collector potential of the light receiving transistor 6 becomes substantially the same as the emitter potential, and a voltage substantially the same as the input voltage is applied to the Zener diode 3.

次に、ＦＥＴ４がオンした後、ツェナーダイオード３に印加される入力電圧がツェナーダイオード３の降伏電圧（第２の所定電圧）より低くなると、ツェナーダイオード２、３に電流が流れなくなり、ＦＥＴ４のゲート電位が低下しＦＥＴ４はオフする。そして、ＦＥＴ４がオフすると、発光ダイオード５にも電流が流れなくなり、受光トランジスタ６がオフし出力端子１２の電位が入力端子１１の電位から入力端子１０の電位に切り替わる。 Next, when the input voltage applied to the Zener diode 3 becomes lower than the breakdown voltage (second predetermined voltage) of the Zener diode 3 after the FET 4 is turned on, no current flows through the Zener diodes 2 and 3, and the gate of the FET 4 The potential decreases and the FET 4 is turned off. When the FET 4 is turned off, no current flows through the light emitting diode 5, the light receiving transistor 6 is turned off, and the potential at the output terminal 12 is switched from the potential at the input terminal 11 to the potential at the input terminal 10.

このように、入力電圧がツェナーダイオード２、３それぞれの降伏電圧の合計電圧より高くなると、出力端子１２の電位を入力端子１０の電位から入力端子１１の電位に切り替え、入力電圧がツェナーダイオード３の降伏電圧より低くなると、出力端子１２の電位を入力端子１１の電位から入力端子１０の電位に切り替えているので、出力端子１２の電位を入力端子１０の電位から入力端子１１の電位に切り替えるための閾値と、出力端子１２の電位を入力端子１１の電位から入力端子１０の電位に切り替えるための閾値とを異ならせることができる。これにより、コンパレータを用いることなく出力電圧を変化させるための閾値と変化した出力電圧を元に戻すための閾値とを異ならせることができるので、コンパレータのように電源を別に用意することなくヒステリシス回路を構成することができる。 Thus, when the input voltage becomes higher than the total voltage of the breakdown voltages of the Zener diodes 2 and 3, the potential of the output terminal 12 is switched from the potential of the input terminal 10 to the potential of the input terminal 11. When the breakdown voltage is lower than the breakdown voltage, the potential of the output terminal 12 is switched from the potential of the input terminal 11 to the potential of the input terminal 10, so that the potential of the output terminal 12 is switched from the potential of the input terminal 10 to the potential of the input terminal 11. The threshold value and the threshold value for switching the potential of the output terminal 12 from the potential of the input terminal 11 to the potential of the input terminal 10 can be made different. As a result, the threshold for changing the output voltage without using a comparator can be made different from the threshold for returning the changed output voltage, so that a hysteresis circuit can be used without preparing a separate power supply like a comparator. Can be configured.

次に、このヒステリシス回路１を用いて電源回路を構成する場合を考える。
図２は、ヒステリシス回路１を用いて構成された電源回路の一例を示す図である。なお、図１に示す構成と同じ構成には同じ符号を付している。 Next, a case where a power supply circuit is configured using the hysteresis circuit 1 will be considered.
FIG. 2 is a diagram illustrating an example of a power supply circuit configured using the hysteresis circuit 1. In addition, the same code | symbol is attached | subjected to the same structure as the structure shown in FIG.

図２に示す電源回路２０は、ヒステリシス回路１と、ＦＥＴ２１（遮断スイッチング素子）と、コイル２２及びコンデンサ２３からなるフィルタ回路２４と、抵抗２６と、ツェナーダイオード２５を備えて構成されている。 A power supply circuit 20 shown in FIG. 2 includes a hysteresis circuit 1, an FET 21 (cut-off switching element), a filter circuit 24 including a coil 22 and a capacitor 23, a resistor 26, and a Zener diode 25.

すなわち、ＦＥＴ２１のソースは、ＧＮＤと接続され、ＦＥＴ２１のゲートは、抵抗９、２６とダイオード５を介してコイル２２の一方端と接続されていると共にコンデンサ２３の一方端と接続され、ＦＥＴ２１のドレインは、コンデンサ２３の他方端と接続されている。また、コイル２２の他方端は、電源２９と接続されている。また、ツェナーダイオード２５はＦＥＴ２１のゲートの保護用である。また、負荷３０は、コンデンサ２３に並列に接続されている。 That is, the source of the FET 21 is connected to the GND, and the gate of the FET 21 is connected to one end of the coil 22 through the resistors 9 and 26 and the diode 5 and is connected to one end of the capacitor 23. Is connected to the other end of the capacitor 23. The other end of the coil 22 is connected to the power source 29. The Zener diode 25 is for protecting the gate of the FET 21. The load 30 is connected to the capacitor 23 in parallel.

次に、電源回路２０の動作について説明する。
図３は、ツェナーダイオード２のカソードとツェナーダイオード３のアノードとの間に印加される電圧（以下、ツェナーダイオード間電圧という）の一例を示す図である。なお、図３に示すグラフの縦軸は、ツェナーダイオード間電圧を示し、横軸は、時間を示している。また、図３のグラフ内に示す実線は、正常のとき（例えば、負荷３０以外にモータなど他の負荷に電源２９の電力が供給されている場合であって、ツェナーダイオード間電圧のピークがツェナーダイオード２、３それぞれの降伏電圧の合計電圧より低いとき）のツェナーダイオード間電圧の一例を示している。また、図３のグラフ内に示す破線は、異常のとき（例えば、負荷３０以外にモータなど他の負荷に電源２９の電力が供給されている場合であって、他の負荷により生じた電力が電源回路２０に回生しているときに電源２９が断線し、ツェナーダイオード間電圧のピークがツェナーダイオード２、３それぞれの降伏電圧の合計電圧より高くなるとき）のツェナーダイオード間電圧の一例を示している。また、図３に示す閾値１は、ツェナーダイオード２、３それぞれの降伏電圧の合計電圧を示し、この閾値１を超える電圧は、負荷３０にとって過電圧になるものとする。また、閾値２は、ツェナーダイオード３の降伏電圧を示している。 Next, the operation of the power supply circuit 20 will be described.
FIG. 3 is a diagram illustrating an example of a voltage applied between the cathode of the Zener diode 2 and the anode of the Zener diode 3 (hereinafter referred to as an Zener diode voltage). In addition, the vertical axis | shaft of the graph shown in FIG. 3 shows the voltage between Zener diodes, and the horizontal axis has shown time. Also, the solid line shown in the graph of FIG. 3 indicates a normal state (for example, when the power of the power source 29 is supplied to another load such as a motor in addition to the load 30, and the peak of the voltage between the zener diodes is An example of the voltage between the Zener diodes when the breakdown voltage is lower than the total breakdown voltage of the diodes 2 and 3 is shown. Also, the broken line shown in the graph of FIG. 3 indicates an abnormality (for example, when the power of the power source 29 is supplied to another load such as a motor in addition to the load 30, and the power generated by the other load is An example of the voltage between the Zener diodes when the power supply 29 is disconnected during regeneration in the power supply circuit 20 and the peak of the voltage between the Zener diodes is higher than the total voltage of the breakdown voltages of the Zener diodes 2 and 3 is shown. Yes. Further, the threshold value 1 shown in FIG. 3 indicates the total voltage of the breakdown voltages of the Zener diodes 2 and 3, and a voltage exceeding the threshold value 1 is an overvoltage for the load 30. The threshold 2 indicates the breakdown voltage of the Zener diode 3.

まず、図３の実線が示すように、ツェナーダイオード間電圧が正常のとき、ツェナーダイオード間電圧は、閾値１を超えないため、ＦＥＴ４はオフしたままである。そのため、ＦＥＴ２１のゲートには、ＦＥＴ２１のオン電圧よりも高い電圧が印加され、ＦＥＴ２１はオンしている。ＦＥＴ２１がオンしている間は、電源２９の電力がフィルタ回路２４を介して負荷３０に供給される。 First, as shown by the solid line in FIG. 3, when the voltage between the Zener diodes is normal, the voltage between the Zener diodes does not exceed the threshold value 1, so that the FET 4 remains off. Therefore, a voltage higher than the ON voltage of the FET 21 is applied to the gate of the FET 21, and the FET 21 is turned on. While the FET 21 is on, power from the power source 29 is supplied to the load 30 via the filter circuit 24.

次に、図３の破線が示すように、ツェナーダイオード間電圧が異常となり、ツェナーダイオード間電圧が閾値１より高くなると、ＦＥＴ４のゲート電位が上昇しＦＥＴ４はオンする。そのため、ダイオード５と抵抗２６との間の電位が入力端子１１の電位となり、ダイオード５と抵抗２６との間の電位が低下しＦＥＴ２１がオフする。ＦＥＴ２１がオフすると、電源２９と負荷３０とをつなぐ経路が遮断され電源２９の電力が負荷３０に供給されなくなる。これにより、過電圧が負荷３０に印加されることを防止することができる。 Next, as indicated by the broken line in FIG. 3, when the voltage between the Zener diodes becomes abnormal and the voltage between the Zener diodes becomes higher than the threshold value 1, the gate potential of the FET 4 rises and the FET 4 is turned on. Therefore, the potential between the diode 5 and the resistor 26 becomes the potential of the input terminal 11, the potential between the diode 5 and the resistor 26 is lowered, and the FET 21 is turned off. When the FET 21 is turned off, the path connecting the power source 29 and the load 30 is cut off, and the power of the power source 29 is not supplied to the load 30. Thereby, it is possible to prevent an overvoltage from being applied to the load 30.

また、例えば、回生が終了し、ツェナーダイオード間電圧が異常から正常に戻り、ツェナーダイオード間電圧が閾値２より低くなると、ＦＥＴ４のゲート電位が低下しＦＥＴ４がオフする。そのため、ＦＥＴ２１のゲート電位が上昇し、ＦＥＴ２１がオンし電源の断線が復帰すれば電源２９と負荷３０とをつなぐ経路の遮断が復帰し再び電源２９の電力が負荷３０に供給される。 Further, for example, when regeneration is completed, the voltage between the Zener diodes returns from normal to normal, and the voltage between the Zener diodes becomes lower than the threshold value 2, the gate potential of the FET 4 decreases and the FET 4 is turned off. Therefore, when the gate potential of the FET 21 rises and the FET 21 is turned on and the disconnection of the power source is restored, the disconnection of the path connecting the power source 29 and the load 30 is restored, and the power of the power source 29 is supplied to the load 30 again.

このように、電源回路２０では、ヒステリシス回路１を用いて電源２９と負荷３０とをつなぐ経路の遮断を復帰させるための閾値を、経路を遮断させるための閾値より低く設定しているため、ツェナーダイオード間電圧が閾値１より高くなってから閾値２より低くなるまでＦＥＴ２１をオフさせ続けておくことができる。これにより、図３に示すように、ツェナーダイオード間電圧が閾値１より高くなった後すぐに閾値１より低くなる場合が生じてもＦＥＴ２１のオン、オフを頻繁に行わせないようにすることができる。 Thus, in the power supply circuit 20, the threshold value for restoring the interruption of the path connecting the power supply 29 and the load 30 using the hysteresis circuit 1 is set lower than the threshold value for blocking the path. The FET 21 can be kept off until the voltage between the diodes becomes higher than the threshold value 1 and becomes lower than the threshold value 2. Thereby, as shown in FIG. 3, even when the voltage between the Zener diodes becomes lower than the threshold value 1 immediately after it becomes higher than the threshold value 1, the FET 21 is not frequently turned on and off. it can.

また、ツェナーダイオード間電圧が閾値１より高くなり電源２９と負荷３０とをつなぐ経路が一旦遮断されると、コンデンサ２３にたまった電荷が消費され、コンデンサ２３の両端電圧が０Ｖに近づいていく。そして、コンデンサ２３の両端電圧が０Ｖに近くなったときに、経路の遮断を復帰させてしまうと、コンデンサ２３の電圧が再び閾値１に近づき多くの電流が電源回路２０に流れる。この問題を解決するために、コイル２２の飽和電流を大きくしてインダクタンスを上げることにより経路の遮断が復帰したときの電流のピークを抑えることが考えられるが、この場合、コイル２２の飽和電流を高くするためにコイル２２を大きくする必要があり電源回路２０が大型化してしまうという問題がある。また、コンデンサ２３の両端電圧が０Ｖに近くなったときに、経路の遮断を復帰させてしまうと、電源回路２０に流れる電流のピークがＦＥＴ２１の許容電流を超え、ＦＥＴ２１が破壊されてしまうおそれがあるという問題もある。しかしながら、本実施形態の電源回路２０では、ヒステリシス回路１を用いているため、ツェナーダイオード間電圧が閾値１より高くなった後、すぐにツェナーダイオード間電圧が低くなっても経路の遮断をすぐに復帰させないので、経路の遮断が復帰するときに電源回路２０に流れる電流のピークが高くならない。これにより、体格が小さいコイル２２を使用することができフィルタ回路２４全体を小型化することができる。また、許容電流が小さいＦＥＴ２１を使用することができるので、その分安価なＦＥＴ２１を使用することができ電源回路２０のコストを抑えることができる。 Further, once the voltage between the Zener diodes becomes higher than the threshold value 1 and the path connecting the power source 29 and the load 30 is once interrupted, the electric charge accumulated in the capacitor 23 is consumed, and the voltage across the capacitor 23 approaches 0V. When the voltage across the capacitor 23 is close to 0V, if the interruption of the path is restored, the voltage of the capacitor 23 again approaches the threshold 1 and a large amount of current flows through the power supply circuit 20. In order to solve this problem, it is conceivable to suppress the peak of the current when the interruption of the path is restored by increasing the saturation current of the coil 22 and increasing the inductance. In this case, the saturation current of the coil 22 is reduced. In order to make it high, it is necessary to enlarge the coil 22, and there is a problem that the power supply circuit 20 becomes large. Further, if the interruption of the path is restored when the voltage across the capacitor 23 approaches 0V, the peak of the current flowing through the power supply circuit 20 may exceed the allowable current of the FET 21, and the FET 21 may be destroyed. There is also the problem of being. However, since the power supply circuit 20 of the present embodiment uses the hysteresis circuit 1, after the voltage between the Zener diodes becomes higher than the threshold value 1, the path is immediately interrupted even if the voltage between the Zener diodes immediately decreases. Since it is not restored, the peak of the current flowing through the power supply circuit 20 does not increase when the interruption of the path is restored. Thereby, the coil 22 with a small physique can be used, and the filter circuit 24 whole can be reduced in size. In addition, since the FET 21 having a small allowable current can be used, an inexpensive FET 21 can be used, and the cost of the power supply circuit 20 can be suppressed.

なお、上記実施形態のヒステリシス回路１では、入力端子１０と入力端子１１との間にツェナーダイオード２、３を設ける構成であるが、ツェナーダイオード２、３の代わりに２つの抵抗（第１及び第２の素子）を互いに直列接続して入力端子１０と入力端子１１との間に設けてヒステリシス回路１を構成してもよい。このように構成したヒステリシス回路１では、ＦＥＴ４がオンするとき、上記２つの抵抗と抵抗８とにより分圧される電圧が上記閾値１に対応し、ＦＥＴ４がオフするとき、上記２つの抵抗のうち受光トランジスタ６に並列に接続されない抵抗と抵抗８とにより分圧される電圧が上記閾値２に対応する。 In the hysteresis circuit 1 of the above embodiment, the Zener diodes 2 and 3 are provided between the input terminal 10 and the input terminal 11, but two resistors (first and second resistors) are used instead of the Zener diodes 2 and 3. 2) may be connected in series with each other and provided between the input terminal 10 and the input terminal 11 to constitute the hysteresis circuit 1. In the hysteresis circuit 1 configured as described above, when the FET 4 is turned on, the voltage divided by the two resistors and the resistor 8 corresponds to the threshold value 1, and when the FET 4 is turned off, The voltage divided by the resistor 8 not connected in parallel to the light receiving transistor 6 and the resistor 8 corresponds to the threshold value 2.

このようにヒステリシス回路１を構成しても、コンパレータを用いることなく出力電圧を変化させるための閾値に幅をもたせることができるので、コンパレータのように電源を別に用意することなくヒステリシス回路を構成することができる。
また、ＦＥＴ４やＦＥＴ２１は、ＩＧＢＴなどその他のスイッチング素子で構成されてもよい。 Even if the hysteresis circuit 1 is configured in this way, the threshold value for changing the output voltage can be widened without using a comparator, so that the hysteresis circuit can be configured without preparing a power source like a comparator. be able to.
Moreover, FET4 and FET21 may be comprised by other switching elements, such as IGBT.

また、上記実施形態では、受光トランジスタ６のコレクタ、エミッタがツェナーダオード２のカソード、アノードに接続される構成であるが、受光トランジスタ６のコレクタ、エミッタがツェナーダイオード３のカソード、アノードに接続されてもよい。 In the above embodiment, the collector and emitter of the light receiving transistor 6 are connected to the cathode and anode of the Zener diode 2, but the collector and emitter of the light receiving transistor 6 are connected to the cathode and anode of the Zener diode 3. May be.

また、フォトカプラ７の受光素子は、受光ダイオードなど受光トランジスタ６以外の素子で構成されてもよい。 Further, the light receiving element of the photocoupler 7 may be composed of an element other than the light receiving transistor 6 such as a light receiving diode.

本発明の実施形態のヒステリシス回路を示す図である。It is a figure which shows the hysteresis circuit of embodiment of this invention. 本実施形態のヒステリシス回路を用いた電源回路の一例を示す図である。It is a figure which shows an example of the power supply circuit using the hysteresis circuit of this embodiment. ツェナーダイオード間電圧の一例を示す図である。It is a figure which shows an example of the voltage between Zener diodes.

Explanation of symbols

１ヒステリシス回路
２、３ツェナーダイオード
４ＦＥＴ
５発光ダイオード
６受光トランジスタ
７フォトカプラ
８、９抵抗
１０プラスの入力端子
１１マイナスの入力端子
１２出力端子
２０電源回路
２１ＦＥＴ
２２コイル
２３コンデンサ
２４フィルタ回路
２５ツェナーダイオード
２６抵抗
２９電源
３０負荷 1 Hysteresis circuit 2, 3 Zener diode 4 FET
5 Light-emitting diode 6 Light-receiving transistor 7 Photocoupler 8, 9 Resistance 10 Positive input terminal 11 Negative input terminal 12 Output terminal 20 Power supply circuit 21 FET
22 Coil 23 Capacitor 24 Filter circuit 25 Zener diode 26 Resistance 29 Power supply 30 Load

Claims

First and second elements connected in series with each other;
A switching element that turns on and switches the potential of the output terminal from the first potential to the second potential when a total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage;
When a light receiving element is connected in parallel to one of the first and second elements, and the switching switching element is turned on, the light emitting element emits light and the total voltage is calculated from the first and second elements. A photocoupler applied to the other element of
With
After the switching switching element is turned on, when the voltage applied to the other element becomes lower than a second predetermined voltage that is smaller than the first predetermined voltage, the switching switching element is turned off and the potential of the output terminal becomes Switching from the second potential to the first potential;
A hysteresis circuit characterized by that.

A first element and a second element provided in series with each other between a positive input terminal and a negative input terminal;
Provided between the negative input terminal and the output terminal, and when the total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage, it is turned on and the potential of the output terminal is A switching element that switches from a certain potential to the potential of the negative input terminal;
When a light receiving element is connected in parallel to one of the first and second elements, and the switching switching element is turned on, the light emitting element emits light and the total voltage is calculated from the first and second elements. A photocoupler applied to the other element of
With
After the switching switching element is turned on, when the voltage applied to the other element becomes lower than a second predetermined voltage that is smaller than the first predetermined voltage, the switching switching element is turned off and the potential of the output terminal becomes The potential of the negative input terminal is switched to the certain potential;
A hysteresis circuit characterized by that.

A first element and a second element provided in series with each other between a positive input terminal and a negative input terminal;
Provided between the negative input terminal and the output terminal, and when the total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage, it is turned on and the potential of the output terminal is A switching element that switches from a certain potential to the potential of the negative input terminal;
A light emitting element is provided between the positive input terminal and the switching switching element, and a light receiving element is connected in parallel to the first element provided on the positive input terminal side of the first and second elements. A photocoupler that emits light when the switching switching element is turned on, and applies the total voltage to the second element;
With
After the switching switching element is turned on, when the voltage applied to the second element becomes lower than a second predetermined voltage smaller than the first predetermined voltage, the switching switching element is turned off and the potential of the output terminal Switches from the negative input terminal potential to the certain potential,
A hysteresis circuit characterized by that.

The hysteresis circuit according to any one of claims 1 to 3,
Each of the first and second elements is a Zener diode, and the first predetermined voltage is a total voltage of breakdown voltages of the first and second elements, and the second predetermined voltage. Is the breakdown voltage of the element that is not connected to the light receiving element among the first and second elements.
A hysteresis circuit characterized by that.

The hysteresis circuit according to any one of claims 1 to 3,
Each of the first and second elements is a resistor,
A voltage dividing resistor is connected in series with the first and second elements,
The first predetermined voltage is a voltage divided by the first and second elements and the voltage dividing resistor when the switching switching element is turned on, and the second predetermined voltage is the switching voltage. When the switching element is turned off, the voltage divided by the divided voltage and the element that is not connected to the light receiving element among the first and second elements,
A hysteresis circuit characterized by that.

A first element and a second element provided in series with each other between a power source and GND;
A switching element that turns on when a total voltage applied to each of the first and second elements becomes higher than a first predetermined voltage;
When the switching switching element is turned on, an interruption switching element that interrupts a path connecting the power source and the load;
When a light receiving element is connected in parallel to one of the first and second elements, and the switching switching element is turned on, the light emitting element emits light and the total voltage is calculated from the first and second elements. A photocoupler to be applied to the other element of
With
After the switching switching element is turned on, when the voltage applied to the other element becomes lower than a second predetermined voltage that is smaller than the first predetermined voltage, the switching switching element is turned off and the cutoff switching element is The interruption of the path connecting the power source and the load is restored.
A power supply circuit characterized by that.