JP2008135820A - Heat generation protecting circuit and method - Google Patents

Heat generation protecting circuit and method Download PDF

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JP2008135820A
JP2008135820A JP2006318481A JP2006318481A JP2008135820A JP 2008135820 A JP2008135820 A JP 2008135820A JP 2006318481 A JP2006318481 A JP 2006318481A JP 2006318481 A JP2006318481 A JP 2006318481A JP 2008135820 A JP2008135820 A JP 2008135820A
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channel fet
temperature
terminal
temperature switch
detection output
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JP4826786B2 (en
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Takeshi Ishihara
剛 石原
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NEC Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat generation protecting circuit which is suitable to prevent a component which is large in peak current in operation from generating heat owing to a partial short. <P>SOLUTION: A positive terminal of a battery 104 is connected to a source (S) terminal of a P-channel FET (103), a power terminal of a GSM power amplifier (101) is connected to a drain (D) terminal of the P-channel FET, and a detection output of a temperature switch IC 102 is connected to a gate (G) terminal of the P-channel FET. The temperature switch IC is configured to generate a detection output HIGH when its detected temperature exceeds a predetermined value, and when the detection output HIGH is generated, the P-channel FET is turned off to cut off power supply from the battery to the GSM power amplifier. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、携帯端末のパワーアンプに適用して好適な発熱保護回路に関する。   The present invention relates to a heat generation protection circuit suitable for application to a power amplifier of a portable terminal.

従来、部品がパーシャルショートモードで故障して発熱するのを防ぐために、ヒューズが使われていた。動作時の電流変動が少ない部品では、ヒューズによる発熱保護は有効であるが、例えば、ＧＳＭ(Global System for Mobile communication)携帯端末のパワーアンプなどはバースト動作するため、動作時のピーク電流が２Ａ弱となり、定格２Ａ以上のヒューズが必要となる。   Conventionally, fuses have been used to prevent parts from failing in partial short mode and generating heat. For parts with little current fluctuation during operation, heat generation protection with fuses is effective. For example, power amplifiers for GSM (Global System for Mobile communication) mobile terminals operate in bursts, so the peak current during operation is less than 2A. Therefore, a fuse with a rating of 2A or more is required.

また、移動通信機において過電流による温度上昇を抑えるため、送信増幅器が発熱するとサーミスタの抵抗値が変化し、送信増幅器の温度が閾値を超えるとＦＥＴが送信増幅器の電源を切断することによって、送信増幅器の温度上昇を抑えることができる保護回路がある（例えば、特許文献１参照）。
特開２００５−２６０８６８号公報 Also, in order to suppress the temperature rise due to overcurrent in the mobile communication device, the resistance value of the thermistor changes when the transmission amplifier generates heat, and when the temperature of the transmission amplifier exceeds the threshold, the FET turns off the power of the transmission amplifier, thereby transmitting There is a protection circuit that can suppress the temperature rise of the amplifier (see, for example, Patent Document 1).
JP 2005-260868 A

しかしながら、定格２Ａ以上のヒューズでは、部品がパーシャルショートモードで故障した場合、装置表面の温度が高くなり、最悪の場合、ユーザが火傷を起こす危険がある。すなわち、部品がパーシャルショートモードで故障して、発熱が発生する場合、その部品が正常動作をしているピーク電流以下でも、火傷などの危険性は残ってしまう。このような場合は、ヒューズで保護回路を構成できない。また、発熱検出及び保護回路の制御にソフトウェアが介在している場合、発熱等でソフトウェア動作が正常でなくなる危険性がある。   However, in a fuse with a rating of 2 A or more, when a component fails in the partial short mode, the temperature of the surface of the device becomes high, and in the worst case, there is a risk that the user may be burned. That is, when a part fails in the partial short mode and heat is generated, there is a risk of burns or the like even if the part is below the peak current at which the part is operating normally. In such a case, the protection circuit cannot be configured with a fuse. Further, when software is present in the detection of heat generation and control of the protection circuit, there is a risk that the software operation will not be normal due to heat generation or the like.

また、特許文献１に記載の保護回路では、サーミスタを用いているため、温度上昇に伴い、抵抗値が連続的に変化し、ＦＥＴが完全にＯＦＦ状態とならないことがある。この場合、ＦＥＴのＯＮ抵抗により、ＦＥＴが発熱してしまう危険がある。   In addition, since the thermistor is used in the protection circuit described in Patent Document 1, the resistance value may continuously change as the temperature rises, and the FET may not be completely turned off. In this case, there is a risk that the FET generates heat due to the ON resistance of the FET.

さらに、上記保護回路では、ＦＥＴがＯＦＦ状態で温度が下がると、ＦＥＴがＯＮしてしまうため、部品がパーシャルショートモードで故障している場合、ＦＥＴがＯＮ／ＯＦＦを続けてしまい、完全に発熱を止めることができない。   Further, in the above protection circuit, when the temperature is lowered while the FET is OFF, the FET is turned ON. Therefore, when the component is in failure in the partial short mode, the FET continues to be turned ON / OFF, and completely generates heat. I can't stop.

そこで本発明は、動作時のピーク電流が大きい部品の故障により、パーシャルショートして発熱することを防止するのに適した発熱保護回路及び方法を提供することを目的とする。   Therefore, an object of the present invention is to provide a heat generation protection circuit and method suitable for preventing partial short-circuiting and heat generation due to a failure of a component having a large peak current during operation.

上述の課題を解決するため、本発明は、ヒューズの代わりに温度スイッチＩＣとＰチャネルＦＥＴを用い、故障により、温度異常を検出した場合に、ＰチャネルＦＥＴをＯＦＦにして、故障部品の発熱を防止することを特徴とする。また、温度スイッチＩＣは、規定温度よりも温度が上昇して、検出信号がＯＮすると、その後、故障部品の発熱が止まり、温度が下がっても検出信号をＯＦＦしない仕様とすることで、確実に発熱を止めることが可能となる。   In order to solve the above-described problems, the present invention uses a temperature switch IC and a P-channel FET instead of a fuse, and when a temperature abnormality is detected due to a failure, the P-channel FET is turned off to generate heat of the failed component. It is characterized by preventing. In addition, when the temperature switch IC rises above the specified temperature and the detection signal turns ON, the heat generation of the faulty part stops and the detection signal does not turn OFF even if the temperature drops. It becomes possible to stop the heat generation.

また、本発明では、発熱検出及び保護回路の制御をハードウェアのみで構成しているため、より安全性の高い回路となっている。   In the present invention, since the heat generation detection and control of the protection circuit are configured only by hardware, the circuit is more secure.

本発明によれば、部品が故障して、部品が正常動作して流れるピーク電流値よりも少ない電流が流れて発熱する場合においても、確実に発熱を防止することができ、ユーザが火傷などすることの無い安全性の高い装置を提供することが可能となる。   According to the present invention, even when a component breaks down and a current less than the peak current value that flows when the component operates normally flows and generates heat, it is possible to reliably prevent heat generation and burn the user. It is possible to provide a highly safe device without any problems.

さらに、部品が故障して保護回路が作動し、発熱が止まり温度が下がっても、再度、故障した部品への電源供給が再開されることはなく、再発熱を繰り返さないため、安全性の高い装置を提供することが可能となる。   Furthermore, even if a component breaks down and the protection circuit is activated, heat generation stops and the temperature drops, power supply to the failed component will not be resumed, and reheating will not be repeated. An apparatus can be provided.

また、ソフトウェアではなく、ハードウェアにより発熱を防止するため、誤動作の可能性が低く、安定した動作の装置を提供することが可能となる。   Further, since heat generation is prevented not by software but by hardware, it is possible to provide a device that operates stably with low possibility of malfunction.

次に、本発明の最良の形態について図面を参照して説明する。   Next, the best mode of the present invention will be described with reference to the drawings.

ＴＤＭＡ(Time Division Multiple Access)方式携帯端末において、送信用パワーアンプのメイン電源ラインにＰチャネル電界効果トランジスタ（以下、ＦＥＴ）を挿入し、ＰチャネルＦＥＴのゲートに、温度スイッチＩＣの検出信号出力を接続し、保護回路を構成する。   In a TDMA (Time Division Multiple Access) portable terminal, a P-channel field effect transistor (hereinafter referred to as FET) is inserted into the main power line of the transmission power amplifier, and the detection signal output of the temperature switch IC is output to the gate of the P-channel FET. Connect and configure the protection circuit.

第１の実施例の構成について、図１を参照して説明する。本実施例は、ＧＳＭ方式の送信用パワーアンプ（以下、ＧＳＭパワーアンプ）１０１、温度を検出する温度スイッチＩＣ１０２、ＰチャネルＦＥＴ１０３、バッテリ１０４、及びＧＳＭ携帯端末１０５から構成される。ＧＳＭ携帯端末の基板に、ＧＳＭパワーアンプ１０１、温度スイッチＩＣ１０２、ＰチャネルＦＥＴ１０３が実装されており、バッテリ１０４は外付けでＧＳＭ携帯端末１０５に接続される構成となっている。   The configuration of the first embodiment will be described with reference to FIG. This embodiment includes a GSM transmission power amplifier (hereinafter referred to as GSM power amplifier) 101, a temperature switch IC 102 for detecting temperature, a P-channel FET 103, a battery 104, and a GSM portable terminal 105. A GSM power amplifier 101, a temperature switch IC 102, and a P-channel FET 103 are mounted on the substrate of the GSM portable terminal, and the battery 104 is externally connected to the GSM portable terminal 105.

一般のＧＳＭ携帯端末では、バッテリ１０４のプラス端子は、ＧＳＭパワーアンプ１０１の電源端子に直接接続される。しかし、本発明では、バッテリ１０４のプラス端子は、ＰチャネルＦＥＴ１０３のソース（Ｓ）端子に接続され、ＧＳＭパワーアンプ１０１の電源端子は、ＰチャネルＦＥＴ１０３のドレイン（Ｄ）端子に接続される。また、ＰチャネルＦＥＴ１０３のゲート（Ｇ）端子は、温度スイッチＩＣ１０２の検出出力が接続される。なお、温度スイッチＩＣ１０２の電源端子には、バッテリ１０４のプラス端子が接続される構成となる。   In a general GSM portable terminal, the positive terminal of the battery 104 is directly connected to the power supply terminal of the GSM power amplifier 101. However, in the present invention, the positive terminal of the battery 104 is connected to the source (S) terminal of the P-channel FET 103, and the power supply terminal of the GSM power amplifier 101 is connected to the drain (D) terminal of the P-channel FET 103. Further, the detection output of the temperature switch IC 102 is connected to the gate (G) terminal of the P-channel FET 103. Note that the positive terminal of the battery 104 is connected to the power supply terminal of the temperature switch IC 102.

本発明に用いるＦＥＴは、ソースの電圧が常時ＨＩＧＨで、正常時にＯＮする必要があるため、ＰチャネルＦＥＴでなければならない。ＮチャネルＦＥＴを用いることはできない。   The FET used in the present invention must be a P-channel FET because the source voltage is always HIGH and needs to be turned on in a normal state. N-channel FETs cannot be used.

温度スイッチＩＣ１０２は、内蔵されている温度センサー部で温度を検出する。このため、装置表面にて、火傷する温度を考慮して、規定温度を設定している。本実施例では、温度センサー部にて規定温度（例えば、７５℃）を検出すると、検出出力がＬＯＷ→ＨＩＧＨとなる。その時の装置表面温度は、それよりも低くなる。装置表面温度と温度スイッチＩＣ部の温度差は、実装にもよるが、例えば１０℃程度と見込む。   The temperature switch IC 102 detects the temperature with a built-in temperature sensor unit. For this reason, the specified temperature is set on the surface of the apparatus in consideration of the burn temperature. In the present embodiment, when a specified temperature (for example, 75 ° C.) is detected by the temperature sensor unit, the detection output is changed from LOW to HIGH. The apparatus surface temperature at that time becomes lower than that. The temperature difference between the device surface temperature and the temperature switch IC portion is expected to be about 10 ° C., for example, though it depends on the mounting.

次に本実施例の動作について、図１を参照して説明する。まず初めに、ＧＳＭ携帯端末１０５にバッテリ１０４を接続した状態で、ＧＳＭパワーアンプ１０１が故障していない場合の動作を説明する。この状態では、温度スイッチＩＣ１０２は、規定温度以下のため、検出出力はＬＯＷ（グランドレベル）となる。温度スイッチＩＣ１０２の検出出力がＬＯＷであると、ＰチャネルＦＥＴ１０３はＯＮ状態となり、バッテリ１０４からＧＳＭパワーアンプ１０１へ電源が供給される。   Next, the operation of this embodiment will be described with reference to FIG. First, an operation when the GSM power amplifier 101 is not malfunctioning in a state where the battery 104 is connected to the GSM portable terminal 105 will be described. In this state, since the temperature switch IC 102 is below the specified temperature, the detection output is LOW (ground level). When the detection output of the temperature switch IC 102 is LOW, the P-channel FET 103 is turned on, and power is supplied from the battery 104 to the GSM power amplifier 101.

次に、上記状態でＧＳＭパワーアンプ１０１がＧＳＭ通話時に正常動作する場合の動作を説明する。この状態では、ＧＳＭパワーアンプ１０１には、ピークで２Ａ弱の電流が流れる場合があるが、正常動作しているため、設計どおりの発熱量となり、規定温度以下のため、検出出力はＬＯＷ（グランドレベル）となる。温度スイッチＩＣ１０２の検出出力がＬＯＷであると、ＰチャネルＦＥＴ１０３はＯＮ状態となり、バッテリ１０４からＧＳＭパワーアンプ１０１へ電源が供給される。   Next, an operation when the GSM power amplifier 101 operates normally during a GSM call in the above state will be described. In this state, a current of less than 2 A may flow through the GSM power amplifier 101 in a peak, but since it is operating normally, the amount of heat generated is as designed, and the detected output is LOW (ground) because it is below the specified temperature. Level). When the detection output of the temperature switch IC 102 is LOW, the P-channel FET 103 is turned on, and power is supplied from the battery 104 to the GSM power amplifier 101.

次に、ＧＳＭパワーアンプ１０１がパーシャルショートモードで故障した場合を考える。パーシャルショートモードで故障し、２Ａ程度の電流が流れる場合、ＧＳＭパワーアンプ１０１は発熱し、温度スイッチＩＣ１０２の検出温度が規定値を超えると、温度スイッチＩＣ１０２の検出出力はＨＩＧＨ（バッテリ電圧レベル）となる。検出出力がＨＩＧＨであると、ＰチャネルＦＥＴ１０３はＯＦＦ状態となり、バッテリ１０４からＧＳＭパワーアンプ１０１への電源供給が遮断する。ＧＳＭパワーアンプ１０１への電源供給が遮断すると、ＧＳＭパワーアンプ１０１の発熱は止まり、装置の表面温度はユーザが火傷するには至らない。   Next, consider a case where the GSM power amplifier 101 fails in the partial short mode. When a failure occurs in the partial short mode and a current of about 2 A flows, the GSM power amplifier 101 generates heat. When the detected temperature of the temperature switch IC 102 exceeds a specified value, the detected output of the temperature switch IC 102 becomes HIGH (battery voltage level). Become. When the detection output is HIGH, the P-channel FET 103 is turned off, and the power supply from the battery 104 to the GSM power amplifier 101 is cut off. When the power supply to the GSM power amplifier 101 is cut off, the heat generation of the GSM power amplifier 101 stops and the surface temperature of the apparatus does not cause burns to the user.

また、発熱が止まり、温度が規定値より下がっても、温度スイッチＩＣ１０２の検出出力はＨＩＧＨ（バッテリ電圧レベル）を維持するため、再度、発熱するには至らない。温度スイッチＩＣ１０２の検出出力は、バッテリ１０４を取り外すか、バッテリが所定の電圧値以下になった場合、リセットされる。このため、バッテリ１０４を接続したまま、電源をオン／オフしても、再びパーシャルショートによって発熱することはない。なお、外部からのリセット信号によって温度スイッチＩＣ１０２の検出出力をリセットする構成とすることもできる。   Even if the heat generation stops and the temperature falls below the specified value, the detection output of the temperature switch IC 102 maintains HIGH (battery voltage level), so that it does not generate heat again. The detection output of the temperature switch IC 102 is reset when the battery 104 is removed or when the battery becomes a predetermined voltage value or less. For this reason, even if the power is turned on / off with the battery 104 connected, the partial short circuit does not generate heat again. Note that the detection output of the temperature switch IC 102 can be reset by an external reset signal.

第２の実施例の構成について、図２を参照して説明する。温度スイッチＩＣ２０２の出力をＣＰＵ２０６へ入力し、ＣＰＵ２０６は、温度スイッチＩＣ１０２の検出出力がＨＩＧＨ（バッテリ電圧レベル）になると、装置の動作を止めて、表示デバイス２０７へアラーム（例えば、“故障したので、お近くのショップへご相談下さい”など）を表示させる。これによって、ユーザは、装置が故障したことをすぐに認識できるため、サービス品質を向上することができる。また、スピーカからの音声でアラームを出力する構成とすることもできる。他の構成は、第１の実施例と同様である。   The configuration of the second embodiment will be described with reference to FIG. The output of the temperature switch IC 202 is input to the CPU 206, and when the detection output of the temperature switch IC 102 becomes HIGH (battery voltage level), the CPU 206 stops the operation of the apparatus and alarms the display device 207 (for example, Please consult your local shop ". As a result, the user can immediately recognize that the device has failed, so that the service quality can be improved. Moreover, it can also be set as the structure which outputs an alarm with the audio | voice from a speaker. Other configurations are the same as those of the first embodiment.

本発明は、ＴＤＭＡ通信が可能な携帯端末（ＧＳＭ方式やＰＤＣ(Personal Digital Cellular)方式など）に利用すると好適である。さらに、バースト動作等を行う能動電子部品の発熱保護に利用できる。   The present invention is preferably used for a portable terminal capable of TDMA communication (GSM system, PDC (Personal Digital Cellular) system, etc.). Furthermore, it can be used for heat generation protection of active electronic components that perform burst operation and the like.

第１の実施例の構成図である。It is a block diagram of a 1st Example. 第２の実施例の構成図である。It is a block diagram of the 2nd Example.

符号の説明Explanation of symbols

１０１，２０１ ＧＳＭパワーアンプ
１０２，２０２ 温度スイッチＩＣ
１０３，２０３ ＰチャネルＦＥＴ
１０４，２０４ バッテリ
１０５，２０５ ＧＳＭ携帯端末
２０６ ＣＰＵ
２０７ 表示デバイス 101, 201 GSM power amplifier 102, 202 Temperature switch IC
103,203 P-channel FET
104, 204 Battery 105, 205 GSM mobile terminal 206 CPU
207 Display device

Claims (6)

能動電子部品と、温度を検出する温度スイッチＩＣと、ＰチャネルＦＥＴとを備え、
前記ＰチャネルＦＥＴのソース端子にバッテリのプラス端子が接続され、前記ＰチャネルＦＥＴのドレイン端子に前記能動電子部品の電源端子が接続され、前記ＰチャネルＦＥＴのゲート端子に温度スイッチＩＣの検出出力が接続され、
前記温度スイッチＩＣは、その検出温度が規定値を超えると、その検出出力がＨＩＧＨとなる様に構成され、
該検出出力がＨＩＧＨになると、前記ＰチャネルＦＥＴはＯＦＦ状態となり、前記バッテリから前記能動電子部品への電源供給を遮断することを特徴とする発熱保護回路。 An active electronic component, a temperature switch IC for detecting temperature, and a P-channel FET;
The positive terminal of the battery is connected to the source terminal of the P channel FET, the power supply terminal of the active electronic component is connected to the drain terminal of the P channel FET, and the detection output of the temperature switch IC is connected to the gate terminal of the P channel FET. Connected,
The temperature switch IC is configured such that when the detected temperature exceeds a specified value, the detected output becomes HIGH,
When the detection output becomes HIGH, the P-channel FET is turned off to cut off power supply from the battery to the active electronic component. 前記温度スイッチＩＣの検出出力は、温度が前記規定値より下がっても、ＨＩＧＨを維持することを特徴とする請求項１に記載の発熱保護回路。   2. The heat generation protection circuit according to claim 1, wherein the detection output of the temperature switch IC maintains HIGH even when the temperature falls below the specified value. 装置を制御するＣＰＵをさらに備え、
前記温度スイッチＩＣの検出出力を該ＣＰＵへ入力し、
該ＣＰＵは、温度スイッチＩＣの検出出力がＨＩＧＨになると、前記装置の動作を止めて、アラームを出力することを特徴とする請求項１に記載の発熱保護回路。 A CPU for controlling the apparatus;
The detection output of the temperature switch IC is input to the CPU,
2. The heat generation protection circuit according to claim 1, wherein when the detection output of the temperature switch IC becomes HIGH, the CPU stops the operation of the device and outputs an alarm. 前記能動電子部品が、ＴＤＭＡ通信用のパワーアンプであることを特徴とする請求項１に記載の発熱保護回路。   The heat protection circuit according to claim 1, wherein the active electronic component is a power amplifier for TDMA communication. 温度を検出する温度スイッチＩＣと、ＰチャネルＦＥＴを用いた能動電子部品の発熱保護方法であって、
前記ＰチャネルＦＥＴのソース端子にバッテリのプラス端子を接続し、
前記ＰチャネルＦＥＴのドレイン端子に前記能動電子部品の電源端子を接続し、
前記ＰチャネルＦＥＴのゲート端子に温度スイッチＩＣの検出出力を接続し、
前記温度スイッチＩＣは、その検出温度が規定値を超えると、その検出出力をＨＩＧＨとし、
該検出出力がＨＩＧＨになると、前記ＰチャネルＦＥＴはＯＦＦ状態となり、前記バッテリから前記能動電子部品への電源供給を遮断することを特徴とする発熱保護方法。 A temperature switch IC for detecting temperature and a heat protection method for active electronic components using a P-channel FET,
Connect the positive terminal of the battery to the source terminal of the P-channel FET,
Connecting the power supply terminal of the active electronic component to the drain terminal of the P-channel FET;
The detection output of the temperature switch IC is connected to the gate terminal of the P-channel FET,
When the detected temperature exceeds a specified value, the temperature switch IC sets its detected output to HIGH,
When the detection output becomes HIGH, the P-channel FET is turned off, and the power supply from the battery to the active electronic component is cut off. 前記温度スイッチＩＣの検出出力は、温度が前記規定値より下がっても、ＨＩＧＨを維持することを特徴とする請求項５に記載の発熱保護方法。   6. The heat generation protection method according to claim 5, wherein the detection output of the temperature switch IC maintains HIGH even when the temperature falls below the specified value.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010150891A1 (en) * 2009-06-26 2010-12-29 京セラ株式会社 Portable electronic device
WO2013151111A1 (en) 2012-04-05 2013-10-10 Yazaki Corporation Overheat protection circuit and overheat protection method
JP5695271B1 (en) * 2013-09-19 2015-04-01 株式会社小松製作所 Communication apparatus and work vehicle equipped with the same
JP2018014271A (en) * 2016-07-21 2018-01-25 浜井電球工業株式会社 Rectifier for outdoor led illumination, and outdoor led illumination device using the same
JP2022124173A (en) * 2021-02-15 2022-08-25 株式会社ミヤワキ Measuring device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06244414A (en) * 1993-02-22 1994-09-02 Hitachi Ltd Protective circuit and semiconductor device containing the same
JPH11201830A (en) * 1997-11-17 1999-07-30 Fuji Electric Co Ltd Temperature detection function incorporating driver ic
JP2005260868A (en) * 2004-03-15 2005-09-22 Nec Saitama Ltd Mobile communication apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06244414A (en) * 1993-02-22 1994-09-02 Hitachi Ltd Protective circuit and semiconductor device containing the same
JPH11201830A (en) * 1997-11-17 1999-07-30 Fuji Electric Co Ltd Temperature detection function incorporating driver ic
JP2005260868A (en) * 2004-03-15 2005-09-22 Nec Saitama Ltd Mobile communication apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010150891A1 (en) * 2009-06-26 2010-12-29 京セラ株式会社 Portable electronic device
JP2011010135A (en) * 2009-06-26 2011-01-13 Kyocera Corp Portable electronic apparatus
US8532702B2 (en) 2009-06-26 2013-09-10 Kyocera Corporation Mobile electronic device with sound output function
WO2013151111A1 (en) 2012-04-05 2013-10-10 Yazaki Corporation Overheat protection circuit and overheat protection method
CN104205635A (en) * 2012-04-05 2014-12-10 矢崎总业株式会社 Overheat protection circuit and overheat protection method
JP5695271B1 (en) * 2013-09-19 2015-04-01 株式会社小松製作所 Communication apparatus and work vehicle equipped with the same
KR20150068351A (en) * 2013-09-19 2015-06-19 가부시키가이샤 고마쓰 세이사쿠쇼 Communication device and working vehicle provided with the same
US9399857B2 (en) 2013-09-19 2016-07-26 Komatsu Ltd. Communication device and working vehicle provided with the same
KR101700258B1 (en) * 2013-09-19 2017-01-26 가부시키가이샤 고마쓰 세이사쿠쇼 Communication device and working vehicle provided with the same
JP2018014271A (en) * 2016-07-21 2018-01-25 浜井電球工業株式会社 Rectifier for outdoor led illumination, and outdoor led illumination device using the same
JP2022124173A (en) * 2021-02-15 2022-08-25 株式会社ミヤワキ Measuring device
JP7244118B2 (en) 2021-02-15 2023-03-22 株式会社ミヤワキ Measuring device

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