JP2007192690A - Power failure detection circuit - Google Patents

Power failure detection circuit Download PDF

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JP2007192690A
JP2007192690A JP2006011861A JP2006011861A JP2007192690A JP 2007192690 A JP2007192690 A JP 2007192690A JP 2006011861 A JP2006011861 A JP 2006011861A JP 2006011861 A JP2006011861 A JP 2006011861A JP 2007192690 A JP2007192690 A JP 2007192690A
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power failure
failure detection
schmitt trigger
reset
circuit
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Hironari Kawai
裕也 川合
Takenori Nakanishi
武徳 中西
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Tietech Co Ltd
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Tietech Co Ltd
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  • Emergency Protection Circuit Devices (AREA)
  • Stand-By Power Supply Arrangements (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power failure detection circuit which can stably detect the power failure of an AC power source and a return from the power failure. <P>SOLUTION: The power failure detection circuit is provided in various kinds of electronic instruments driven by an AC power source. A photocoupler 17 is connected to the AC power source 10, and an integration circuit 18 is connected to the output side of the photocoupler 17. A reset IC 22 and a Schmitt trigger IC 24 are connected to the integration circuit 18 in parallel. The output of the reset IC 22 is pulled up by the output of the Schmitt trigger IC 24. The difference between the power failure detection voltage and the return detection voltage is thereby reduced, allowing to stably detect the power failure detection voltage and the return detection voltage. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、交流電源の停電を検出する停電検出回路に関する。   The present invention relates to a power failure detection circuit that detects a power failure of an AC power supply.

交流電源で駆動する種々の電子機器、例えばコンピュータや通信機等においては、交流電源の停電（所定電圧以下への電圧低下）を検出する停電検出回路を備えている。   Various electronic devices driven by an AC power source, such as a computer or a communication device, are provided with a power failure detection circuit that detects a power failure (voltage drop below a predetermined voltage) of the AC power source.

従来、停電検出回路として、交流電源にフォトカプラを接続し、フォトカプラの出力側に積分回路とロジックＩＣを設け、積分回路の出力電圧がロジックＩＣのスレッショルド電圧レベルより高いときに入力交流電源が正常であると判断し、積分回路の出力電圧がロジックＩＣのスレッショルド電圧レベル以下になったときに停電（電源断または電圧低下）と判定するものがある。   Conventionally, as a power failure detection circuit, a photocoupler is connected to an AC power supply, an integration circuit and a logic IC are provided on the output side of the photocoupler, and when the output voltage of the integration circuit is higher than the threshold voltage level of the logic IC, the input AC power supply Some of them are determined to be normal, and when the output voltage of the integration circuit becomes lower than the threshold voltage level of the logic IC, it is determined that there is a power failure (power failure or voltage drop).

しかし、前記ロジックＩＣを設けた停電検出回路においては、ロジックＩＣの出力信号が不安定であるという問題がある。   However, the power failure detection circuit provided with the logic IC has a problem that the output signal of the logic IC is unstable.

特開平９−３１８６８０号公報JP 9-318680 A

本発明は前記の点に鑑みなされたものであり、交流電源の停電及び停電からの復帰を安定して検出することができる停電検出回路の提供を目的とする。   The present invention has been made in view of the above points, and an object thereof is to provide a power failure detection circuit capable of stably detecting a power failure of an AC power source and a return from a power failure.

本発明は、交流電源の停電を検出する回路において、交流電源にフォトカプラを接続し、前記フォトカプラの出力側には積分回路を接続すると共に、前記積分回路にリセットＩＣとシュミットトリガＩＣを並行に接続し、前記リセットＩＣの出力を前記シュミットトリガＩＣの出力でプルアップすることを特徴とする。   The present invention provides a circuit for detecting a power failure of an AC power supply, wherein a photocoupler is connected to the AC power supply, an integration circuit is connected to the output side of the photocoupler, and a reset IC and a Schmitt trigger IC are connected in parallel to the integration circuit And the output of the reset IC is pulled up by the output of the Schmitt trigger IC.

本発明とは異なり、図３に示すように、シュミットトリガＩＣを設けることなくプルアップ用抵抗６５をリセットＩＣ６２の出力側に接続すると、次の理由により、電源停電状態から復帰した際の復帰検出電圧と電源正常供給状態から停電した際の停電検出電圧とが異なり、電子機器の安定した作動が得難くなる問題がある。すなわち、電源復帰を検出する場合には、電源復帰までＶｏｕｔがＬｏｗとなっているため、プルアップ用抵抗６５にも電流が流れて積分回路５８のコンデンサ６０が充電され難くなり、その結果、交流電源の電圧が高くならないとＶＤＤが上昇せず、復帰検出電圧が高いものとなる。一方、停電を検出する場合には、電源正常供給状態から停電するまでＶｏｕｔがＨｉｇｈとなっているため、プルアップ用抵抗６５に電流が流れ難く、積分回路５８のコンデンサ６０が充電されやすくなり、交流電源の電圧が低くてもＶＤＤが高い電圧を維持できることから停電検出電圧が低くなる。実測では、抵抗６１が１０ｋΩ、抵抗６５が１０ｋΩの時に復帰検出電圧と停電検出電圧の差が１０〜３０Ｖ程度、抵抗６１が１０ｋΩ、抵抗６５が１００ｋΩの時に１０Ｖ以下であった。符号５１はトランス、５２は抵抗、５３〜５６はツェナーダイオード、５７はフォトカプラ、５８は積分回路、５９は抵抗、６０はコンデンサ、６１は抵抗、６２はリセットＩＣ、６３はコンデンサ、６５は抵抗である。 Unlike the present invention, as shown in FIG. 3, when the pull-up resistor 65 is connected to the output side of the reset IC 62 without providing a Schmitt trigger IC, the return detection upon recovery from the power failure state due to the following reason. There is a problem that it is difficult to obtain a stable operation of the electronic device because the voltage and the power failure detection voltage when a power failure occurs from the normal power supply state are different. That is, when power recovery is detected, Vout is low until power recovery, so that a current also flows through the pull-up resistor 65, making it difficult to charge the capacitor 60 of the integration circuit 58. If the voltage of the power supply does not increase, V DD does not increase and the return detection voltage becomes high. On the other hand, when detecting a power failure, Vout remains High until the power failure occurs from the normal power supply state, so that it is difficult for current to flow through the pull-up resistor 65, and the capacitor 60 of the integration circuit 58 is easily charged. Even if the voltage of the AC power supply is low, the power failure detection voltage is low because V DD can maintain a high voltage. In actual measurement, when the resistance 61 is 10 kΩ and the resistance 65 is 10 kΩ, the difference between the return detection voltage and the power failure detection voltage is about 10 to 30 V, and when the resistance 61 is 10 kΩ and the resistance 65 is 100 kΩ, it is 10 V or less. Reference numeral 51 is a transformer, 52 is a resistor, 53 to 56 are Zener diodes, 57 is a photocoupler, 58 is an integrating circuit, 59 is a resistor, 60 is a capacitor, 61 is a resistor, 62 is a reset IC, 63 is a capacitor, and 65 is a resistor It is.

それに対し、本発明においては、積分回路にリセットＩＣとシュミットトリガＩＣを並行に接続し、リセットＩＣの出力をシュミットトリガＩＣの出力でプルアップしている。シュミットトリガＩＣの入力抵抗は非常に大きいため、図１及び図２に示すように、シュミットトリガＩＣ２４は一種のバッファとしての役割を果たす。したがって、積分回路１８のコンデンサ２０に対するプルアップ用抵抗２６の影響を小さくすることができ、停電検出電圧と復帰検出電圧の差を小さくすることができる。実測では、停電検出電圧と復帰検出電圧の差は大きくても１Ｖ程度であった。   On the other hand, in the present invention, the reset IC and the Schmitt trigger IC are connected in parallel to the integration circuit, and the output of the reset IC is pulled up by the output of the Schmitt trigger IC. Since the input resistance of the Schmitt trigger IC is very large, as shown in FIGS. 1 and 2, the Schmitt trigger IC 24 serves as a kind of buffer. Therefore, the influence of the pull-up resistor 26 on the capacitor 20 of the integrating circuit 18 can be reduced, and the difference between the power failure detection voltage and the recovery detection voltage can be reduced. In actual measurement, the difference between the power failure detection voltage and the recovery detection voltage was about 1 V at most.

以下本発明の実施形態を説明する。図１は本発明の第１実施形態における停電検出回路の構成を示すブロック図、図２は第２実施形態における停電検出回路の構成を示すブロック図である。   Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a configuration of a power failure detection circuit according to the first embodiment of the present invention, and FIG. 2 is a block diagram showing a configuration of a power failure detection circuit according to the second embodiment.

図１に示す停電検出回路１Ａは、コンピュータ等の電子機器に設けられる。この停電検出回路１Ａは、交流電源１０に抵抗１２とツェナーダイオード１３〜１６が接続され、さらにフォトカプラ１７が接続されている。また、前記交流電源１０にはトランス１１が接続され、前記トランスの二次側には直流電源装置を介して負荷部が接続されている。前記抵抗１２はフォトカプラ１７への入力電流を制限し、一方、前記ツェナーダイオード１３〜１６は停電検出電圧を調整する。フォトカプラ１７は、発光素子と受光素子とで構成され、交流電源と直流間の絶縁と交流電源の整流を行うものであり、ツェナーダイオードで調整された交流電源によって発光素子が点灯し、それにより受光素子が高抵抗から低抵抗となる。   A power failure detection circuit 1A shown in FIG. 1 is provided in an electronic device such as a computer. In this power failure detection circuit 1A, a resistor 12 and Zener diodes 13 to 16 are connected to an AC power source 10, and a photocoupler 17 is further connected. A transformer 11 is connected to the AC power source 10, and a load unit is connected to the secondary side of the transformer via a DC power source device. The resistor 12 limits the input current to the photocoupler 17, while the Zener diodes 13-16 adjust the power failure detection voltage. The photocoupler 17 is composed of a light emitting element and a light receiving element, and performs insulation between the AC power source and DC and rectification of the AC power source. The light emitting element is turned on by the AC power source adjusted by the Zener diode, thereby The light receiving element changes from high resistance to low resistance.

フォトカプラ１７の受光素子には積分回路（整流回路）１８が接続されている。積分回路１８の抵抗１９はコンデンサ２０への突入電流を制限し、コンデンサ２０は交流電源整流後の平滑化を行い、また、抵抗２１は交流電源停電時におけるコンデンサ２０を放電させる。   An integrating circuit (rectifier circuit) 18 is connected to the light receiving element of the photocoupler 17. The resistor 19 of the integrating circuit 18 limits the inrush current to the capacitor 20, the capacitor 20 performs smoothing after AC power supply rectification, and the resistor 21 discharges the capacitor 20 at the time of AC power supply interruption.

積分回路１８にはリセットＩＣ２２とシュミットトリガＩＣ２４が並行に接続され、さらにシュミットトリガＩＣ２４にプルアップ用抵抗２６が接続されている。前記リセットＩＣ２２は、設定閾（しきい）値に対する入力ＶＤＤ電圧の変化を精度良く検出することができる。前記リセットＩＣ２２の出力は、オープンドレインであり、シュミットトリガＩＣ２４の出力によりプルアップされる。符号２３はコンデンサである。 A reset IC 22 and a Schmitt trigger IC 24 are connected in parallel to the integration circuit 18, and a pull-up resistor 26 is connected to the Schmitt trigger IC 24. The reset IC 22 can accurately detect a change in the input V DD voltage with respect to a set threshold value. The output of the reset IC 22 is an open drain and is pulled up by the output of the Schmitt trigger IC 24. Reference numeral 23 denotes a capacitor.

この停電検出回路１Ａにおいては、正常に交流電源が供給されている非停電のときは、ＶＤＤ、リセットＩＣ２２の出力及びＶｏｕｔがＨレベルとなり、一方、交流電源が停電（電圧低下）すると、シュミットトリガＩＣ２４の出力も落ちて、ＶＤＤ、リセットＩＣ２２の出力及びＶｏｕｔがＨからＬレベルになる。前記Ｖｏｕｔは、電子機器のＭＰＵによって検出される。 In this power failure detection circuit 1A, when the AC power supply is normally supplied and when there is no power failure, V DD , the output of the reset IC 22 and Vout become H level. The output of the trigger IC 24 also drops, and V DD , the output of the reset IC 22 and Vout change from H to L level. The Vout is detected by the MPU of the electronic device.

また、出力先の回路との干渉を避けるためには、図２に示す停電検出回路１Ｂのように、リセットＩＣ２２の出力側に、さらにシュミットトリガＩＣ２７を接続するのが好ましい。   In order to avoid interference with the output destination circuit, it is preferable to further connect a Schmitt trigger IC 27 to the output side of the reset IC 22 as in the power failure detection circuit 1B shown in FIG.

前記停電検出回路１Ａ及び１Ｂによれば、積分回路１８にリセットＩＣ２２とシュミットトリガＩＣ２４が並行に接続されていることにより、前記のように、積分回路１８におけるコンデンサ２０に対するプルアップ用抵抗２６の影響を小さくすることができ、停電検出電圧と復帰検出電圧の差を小さくすることができる。   According to the power failure detection circuits 1A and 1B, since the reset IC 22 and the Schmitt trigger IC 24 are connected in parallel to the integration circuit 18, the influence of the pull-up resistor 26 on the capacitor 20 in the integration circuit 18 as described above. And the difference between the power failure detection voltage and the return detection voltage can be reduced.

なお、図１及び図２の実施形態においては、積分回路１８にリセットＩＣ２２と並行に接続されるシュミットトリガＩＣ２４を１つとしたが、複数のシュミットトリガＩＣを直列に設けてもよい。さらに、図２の実施形態においては、リセットＩＣ２２の出力側に接続されるシュミットトリガＩＣ２７を１つとしたが、複数のシュミットトリガＩＣを直列に設けてもよい。すなわち、前記実施形態で用いたシュミットトリガＩＣ２４，２７は正論理バッファであるが、例えば、前記シュミットトリガＩＣ２４，２７を正論理ＮＯＴ素子とする場合には、正論理ＮＯＴ素子を２つ直列に設ける等である。   In the embodiment of FIGS. 1 and 2, the integration circuit 18 has one Schmitt trigger IC 24 connected in parallel with the reset IC 22, but a plurality of Schmitt trigger ICs may be provided in series. Further, in the embodiment of FIG. 2, one Schmitt trigger IC 27 is connected to the output side of the reset IC 22, but a plurality of Schmitt trigger ICs may be provided in series. That is, the Schmitt trigger ICs 24 and 27 used in the embodiment are positive logic buffers. For example, when the Schmitt trigger ICs 24 and 27 are positive logic NOT elements, two positive logic NOT elements are provided in series. Etc.

第１実施形態における停電検出回路の構成を示すブロック図である。It is a block diagram which shows the structure of the power failure detection circuit in 1st Embodiment. 第２実施形態における停電検出回路の構成を示すブロック図である。It is a block diagram which shows the structure of the power failure detection circuit in 2nd Embodiment. 本発明とは異なり、シュミットトリガＩＣを設けない場合のブロック図である。Unlike the present invention, it is a block diagram when no Schmitt trigger IC is provided.

符号の説明Explanation of symbols

１Ａ，１Ｂ 停電検出回路
１０ 交流電源
１１ トランス
１２ 抵抗
１３，１４，１５，１６ ツェナーダイオード
１７ フォトカプラ
１８ 積分回路
１９ 抵抗
２０ コンデンサ
２１ 抵抗
２２ リセットＩＣ
２３ コンデンサ
２４ シュミットトリガＩＣ
２６ 抵抗
２７ シュミットトリガＩＣ
1A, 1B Power failure detection circuit 10 AC power supply 11 Transformer 12 Resistor 13, 14, 15, 16 Zener diode 17 Photocoupler 18 Integration circuit 19 Resistor 20 Capacitor 21 Resistor 22 Reset IC
23 Capacitor 24 Schmitt Trigger IC
26 Resistance 27 Schmitt Trigger IC

Claims (1)

交流電源の停電を検出する回路において、交流電源にフォトカプラを接続し、前記フォトカプラの出力側には積分回路を接続すると共に、前記積分回路にリセットＩＣとシュミットトリガＩＣを並行に接続し、前記リセットＩＣの出力を前記シュミットトリガＩＣの出力でプルアップすることを特徴とする停電検出回路。
In a circuit for detecting a power failure of an AC power supply, a photocoupler is connected to the AC power supply, an integration circuit is connected to the output side of the photocoupler, and a reset IC and a Schmitt trigger IC are connected in parallel to the integration circuit, A power failure detection circuit, wherein the output of the reset IC is pulled up by the output of the Schmitt trigger IC.
JP2006011861A 2006-01-20 2006-01-20 Power failure detection circuit Pending JP2007192690A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010121952A (en) * 2008-11-17 2010-06-03 Panasonic Electric Works Co Ltd Service interruption detecting device for power line communication, and power line communication system
JP2012055086A (en) * 2010-09-01 2012-03-15 Hitachi Maxell Energy Ltd Charging unit and electric apparatus including the same
JP2014219289A (en) * 2013-05-08 2014-11-20 株式会社希望電機 Electroscope
CN109342806A (en) * 2018-11-28 2019-02-15 上海节卡机器人科技有限公司 The exchange wire breakage detector and method of robot

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010121952A (en) * 2008-11-17 2010-06-03 Panasonic Electric Works Co Ltd Service interruption detecting device for power line communication, and power line communication system
JP2012055086A (en) * 2010-09-01 2012-03-15 Hitachi Maxell Energy Ltd Charging unit and electric apparatus including the same
CN103081296A (en) * 2010-09-01 2013-05-01 日立麦克赛尔株式会社 Charging unit and electrical device provided with same
EP2613425A1 (en) * 2010-09-01 2013-07-10 Hitachi Maxell, Ltd. Charging unit and electrical device provided with same
EP2613425A4 (en) * 2010-09-01 2013-07-31 Hitachi Maxell Charging unit and electrical device provided with same
JP2014219289A (en) * 2013-05-08 2014-11-20 株式会社希望電機 Electroscope
CN109342806A (en) * 2018-11-28 2019-02-15 上海节卡机器人科技有限公司 The exchange wire breakage detector and method of robot

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