JP2004152733A

JP2004152733A - Planar warmer

Info

Publication number: JP2004152733A
Application number: JP2002319735A
Authority: JP
Inventors: Hisayasu Katayama; 尚保片山
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-11-01
Filing date: 2002-11-01
Publication date: 2004-05-27
Anticipated expiration: 2022-11-01
Also published as: JP4165186B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar warmer having a controller which is cost-effective and effective in terms of mounting by making it easier to integrate a circuit in which a temperature sensor is used to show impedance characteristics composed of capacity component and resistance component integrally constituted with heaters such as an electric carpet and an electric blanket. <P>SOLUTION: The base is connected to the grounding point side of the alternate current power supply 6 and a direct current power source part 8, and an emitter is connected to a detection electrode wire 4, and by providing a current prevention part 21 wherein the signal current of a temperature sensor 3 is not flown during a positive cycle side period of an alternate current power supply 6 at an emitter of a transistor 9 in which the current determined by impedance of the temperature sensor 3 is flown in the collector, the emitter potential of the transistor 9 is prevented from turning into a negative potential during the positive cycle period of the alternate current power supply 6. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、電気カーペット、電気毛布などのヒータと一体に構成した容量分や抵抗分からなるインピーダンス特性を示す温度センサを使用する面状採暖具に関するものである。
【０００２】
【従来の技術】
従来この種の面状採暖具としては、例えば、図７〜図１０に示すものがあった。図７は温度センサ、検知電極線と一体構成にあるヒータの構造図を示したもので、１は芯線であり、その上にヒータ２を巻回し、その上にプラスチックサーミスタによる温度センサ３を被覆し、その上に検知電極線４を巻回し、更にその上に絶縁用外被５を被覆している。図８は温度センサ３の特性を示したもので、縦軸がインピーダンスＺ、横軸が温度ＴでＬが低い側、Ｈが高い側をあらわす。インピーダンスＺは容量分から決まるインピーダンスＺＣと抵抗分から決まるインピーダンスＺＲの合成値となり、高温側になるほど容量分のインピーダンスＺＣのウエイトが高くなる。
【０００３】
図９にこの温度センサ３を用いた従来例の構成図を示す。図において、６は交流電源、７はヒータ２へ交流電源６を供給制御する電力制御素子、８は直流電源部で各部に直流電圧を供給する。９はベース接地したトランジスタで、エミッタは検知電極線４に接続される（例えば、特許文献１参照）。１０は温度信号部でトランジスタ９のコレクタに流れる電流を電圧変換して信号ＶＴを出力する。１１は温度設定部でヒータ２の温度設定信号Ｖｓを出力する。１２は温度制御部で温度信号部１０の信号ＶＴと温度設定部１１の信号Ｖｓを比較処理して、ヒータ２の温度が設定より低い時、すなわち、ＶＴ＞Ｖｓの時はＨｉ出力となって電力制御素子７を駆動する。温度信号部１０の信号ＶＴは、ヒータ２の温度が低くて温度センサ３のインピーダンスが大きい時は、トランジスタ９のコレクタに流れる電流が小さいため、高い値を示す。逆にヒータ２の温度が高くなり温度センサ３のインピーダンスが小さくなると、トランジスタ９のコレクタに流れる電流が多くなるため、低い値を示すことになる。この温度信号部１０の信号ＶＴを検出することによってヒータ２の温度を、ある設定した温度に制御している。１３はダイオードでトランジスタ９のエミッタベース間の耐圧保証、及び、交流電源６の正サイクル側における温度センサ３の電流を流している。
【０００４】
【特許文献１】
特開平０８−１４５３８８号公報（図１）
【０００５】
【発明が解決しようとする課題】
しかしながら、前記従来の構成では、回路を１チップの集積回路にする場合、寄生動作を発生させてしまう。その動作を図１０とともに説明する。図において、温度センサ３に流れる信号電流Ｉｓは、温度センサ３のインピーダンスが容量分で構成され、特に高温側においては殆どが容量分となるため、交流電源６（Ｖａｃ）に対して、位相が９０°近く進むことになる。温度信号部１０は信号電流Ｉｓの負サイクル側の電流を検出している。従って、温度信号部１０の検出電流は交流電源６（Ｖａｃ）のｂ側、トランジスタ９のベースからエミッタ、検知電極線４、温度センサ３、ヒータ２、交流電源６（Ｖａｃ）のａ側へと流れて、トランジスタ９がオンすると、検出電流の殆どはトランジスタ９のコレクタを流れることになる。そうすると温度検出部１０の抵抗１４とコンデンサ１５によって直流電圧の信号ＶＴに変換される。この時トランジスタ９のエミッタ電位Ｖｂは、回路の基準電圧ＧＮＤよりも負の電圧となってしまう。
【０００６】
そして回路を１チップの集積回路で構成すると、この負の電圧となることで集積回路内部において異常な回路ができる寄生動作が発生してしまう。この寄生動作で発生した回路が影響して温度制御部１２の出力がＨｉ出力となってしまい電力制御素子７のアノードとカソード間の電圧Ｖｓｃｒに示すように、電力制御素子７が交流電源６（Ｖａｃ）の正サイクル時、且つ、信号電流Ｉｓの負サイクル時において連続的にオンしてしまう異常動作が発生する。この異常動作によりヒータ２の温度が上昇し続け、非常に危険な状態となってしまう。
【０００７】
本発明は、前記従来の課題を解決するもので、電気カーペット、電気毛布などのヒータと一体に構成した容量分や抵抗分からなるインピーダンス特性を示す温度センサを使用する回路の集積回路化を容易にして、コスト面や実装面で有効な制御コントローラを有する面状採暖具の提供を目的とする。
【０００８】
【課題を解決するための手段】
前記従来の課題を解決するために、本発明の面状採暖具は、交流電源と直流電源部の接地点側にベースを接続、エミッタを検知電極線側に接続し、温度センサのインピーダンスから決まる電流をコレクタに流すトランジスタのエミッタに、交流電源の正サイクル側期間中は、温度センサの信号電流を流さない電流阻止部を備えたものである。この電流阻止部によってトランジスタのエミッタ電位を、交流電源の正サイクル期間において常に正電位とするものである。
【０００９】
【発明の実施の形態】
請求項１に記載の発明は、交流電源と直流電源部の接地点側にベースを接続、エミッタを検知電極線側に接続し、温度センサのインピーダンスから決まる電流をコレクタに流すトランジスタのエミッタに、交流電源の正サイクル側期間中は、エミッタに流れる電流を打ち消す方向に電流を流す電流阻止部を構成することにより、エミッタ電位を、交流電源の正サイクル期間において常に正電位とすることができる。
【００１０】
請求項２に記載の発明は、特に、交流電源の正サイクル側期間中は、検知電極線とトランジスタのエミッタとの間のインピーダンスを大きくする電流阻止部を構成することにより、エミッタ電位が、交流電源の正サイクル期間において負電位になることを防止することができる。
【００１１】
請求項３に記載の発明は、特に、交流電源の正サイクル側期間中は、トランジスタのベースとエミッタを短絡する電流阻止部を構成することにより、エミッタ電位が、交流電源の正サイクル期間において負電位になることを防止することができる。
【００１２】
【実施例】
以下、本発明の実施例について、図１〜図６を参照しながら説明する。尚、従来例と同一部については、同一番号を付与し、従って、その動作も同じであるので説明を省略する。
【００１３】
（実施例１）
図１は、本発明の第１の実施例における面状採暖具の構成図を示すものである。図１において、２１は電流阻止部で、ダイオード２２、抵抗２３で構成し、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクル期間中において、トランジスタ９のエミッタに流れる電流を打ち消す方向に電流を流す。次に、図２の特性図において、各部の電流と電圧の関係を交流電源６（Ｖａｃ）の波形を基準に説明する。
【００１４】
まず、温度センサ３に流れる信号電流Ｉｓは、温度センサ３のインピーダンスが容量分で構成され、特に高温側においては殆どが容量分となるため、交流電源６（Ｖａｃ）に対して、位相が９０°近く進んだ電流となる。そして、電流阻止部２１に流れる電流Ｉａは、交流電源６（Ｖａｃ）と同位相で、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクルの期間中のみに流れる。従って、トランジスタ９のエミッタに流れる電流Ｉｔは、温度センサ３に流れる信号電流Ｉｓと電流阻止部２１に流れる電流Ｉａの合成電流となる。
【００１５】
ここで電流阻止部２１に流れる電流Ｉａの値を温度センサ３に流れる信号電流Ｉｓの値よりも大きく設定することで、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクルの期間中において、トランジスタ９のエミッタに流れる電流Ｉｔの負側の電流を打ち消すことができ、電流Ｉｔは、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクルの期間中は正側の電流となる。ゆえに、トランジスタ９のエミッタ電位Ｖｂも交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクルの期間中は常に正電位となる。よって、集積回路化した時においても寄生動作の発生がなくなり、電力制御素子７のアノードとカソード間波形Ｖｓｃｒに示すように、オフすべき時には確実にオフさせることができる。
【００１６】
（実施例２）
図３、図４は、本発明の第２の実施例における面状採暖具の構成図および特性図を示すものである。図３において、３１は電流阻止部でフォトトライアックカプラ３２と抵抗３３で構成する。次に動作を図４とともに説明する。電流阻止部３１のフォトトライアックカプラ３２のＬＥＤ部３４には、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクル期間中においては電流が流れず、従って発光しないためにフォトトライアックカプラ３２のトライアック部３５はオフとなる。そして交流電源６（Ｖａｃ）のａ側がマイナス電位の期間である負サイクル期間中においてはＬＥＤ部３４に電流が流れ、発光してトライアック部３５をオン状態とする。ゆえに、温度センサ３に流れる信号電流Ｉｓは交流電源６（Ｖａｃ）の正サイクル期間中は負の電流が流れず、トランジスタ９のエミッタ電流Ｉｔは交流電源６（Ｖａｃ）のａ側がマイナス電位の期間である負サイクル期間中においてのみ流れることになる。よって、トランジスタ９のエミッタ電位Ｖｂも交流電源６（Ｖａｃ）のａ側がマイナス電位の期間である負サイクルの期間中のみ負電位となり、正サイクル期間中は負電位を防止できるので、集積回路化した時においても寄生動作の発生がなくなり、電力制御素子７のアノードとカソード間波形Ｖｓｃｒに示すように、オフすべき時には確実にオフさせることができる。
【００１７】
（実施例３）
図５、図６は、本発明の第３の実施例における面状採暖具の構成図および特性図を示すものである。図５において、４１は電流阻止部でフォトトランジスタカプラ４２と抵抗４３で構成する。次に動作を図６とともに説明する。電流阻止部４１のフォトトランジスタカプラ４２のＬＥＤ部４４には、交流電源６（Ｖａｃ）のａ側がプラス電位の期間である正サイクル期間中において電流が流れ、従ってＬＥＤ部４４は発光してフォトトランジスタカプラ４２のトランジスタ部４５はオンとなる。
【００１８】
そして交流電源６（Ｖａｃ）のａ側がマイナス電位の期間である負サイクル期間中においてはＬＥＤ部４４には電流が流れず、発光しないのでトランジスタ部４５はオフ状態となる。ゆえに、温度センサ３に流れる信号電流Ｉｓの負サイクル側の電流で交流電源６（Ｖａｃ）の正サイクル期間中の電流は、トランジスタ部４５の電流Ｉｃとして流れ、従って、温度センサ３に流れる信号電流Ｉｓの負サイクル側の電流で、交流電源６（Ｖａｃ）の負サイクル期間中の電流だけがトランジスタ９のエミッタ電流Ｉｔとして流れることになる。よって、トランジスタ９のエミッタ電位Ｖｂも交流電源６（Ｖａｃ）のａ側がマイナス電位の期間である負サイクルの期間中のみ負電位となり、正サイクル期間中は負電位を防止できるので、集積回路化した時においても寄生動作の発生がなくなり、電力制御素子７のアノードとカソード間波形Ｖｓｃｒに示すように、オフすべき時には確実にオフさせることができる。
【００１９】
【発明の効果】
以上のように、本発明によれば、交流電源と直流電源部の接地点側にベースを接続、エミッタを検知電極線側に接続し、温度センサのインピーダンスから決まる電流をコレクタに流すトランジスタのエミッタに、交流電源の正サイクル側期間中は、温度センサの信号電流を流さない電流阻止部を備えることにより、トランジスタのエミッタ電位を、交流電源の正サイクル期間においては負電位とならない回路構成とできるものであり、寄生動作が発生しないので回路の集積回路化が容易になり、ゆえに部品点数が少なくなってコストが安く、また、実装スペースが小さい制御コントローラを有する面状採暖具を提供することができるものである。
【図面の簡単な説明】
【図１】本発明の実施例１における面状採暖具の構成図
【図２】本発明の第１の実施例における面状採暖具の特性図
【図３】本発明の第２の実施例における面状採暖具の構成図
【図４】本発明の第２の実施例における面状採暖具の特性図
【図５】本発明の第３の実施例における面状採暖具の構成図
【図６】本発明の第３の実施例における面状採暖具の特性図
【図７】温度センサ、検知電極線と一体構成にあるヒータの構造図
【図８】温度センサの特性図
【図９】従来の面状採暖具の構成図
【図１０】従来の面状採暖具の特性図
【符号の説明】
２ヒータ
３温度センサ
４検知電極線
６交流電源
７電力制御素子
８直流電源部
９トランジスタ
１０温度信号部
１１温度設定部
１２温度制御部
１３ダイオード
２１、３１、４１電流阻止部[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a planar heating device using a temperature sensor exhibiting impedance characteristics composed of a capacitance component and a resistance component integrated with a heater such as an electric carpet or an electric blanket.
[0002]
[Prior art]
Conventionally, as this type of planar heating device, for example, there has been one shown in FIGS. FIG. 7 shows a structural diagram of a heater integrated with a temperature sensor and a detection electrode wire, wherein 1 is a core wire, on which a heater 2 is wound, and on which a plastic thermistor-covered temperature sensor 3 is provided. Then, the detection electrode wire 4 is wound thereon, and the insulating jacket 5 is further coated thereon. FIG. 8 shows the characteristics of the temperature sensor 3, in which the vertical axis represents the impedance Z, and the horizontal axis represents the temperature T and the side where L is low and the side where H is high. The impedance Z is a composite value of the impedance ZC determined by the capacitance and the impedance ZR determined by the resistance, and the higher the temperature, the higher the weight of the impedance ZC by the capacitance.
[0003]
FIG. 9 shows a configuration diagram of a conventional example using the temperature sensor 3. In the figure, 6 is an AC power supply, 7 is a power control element for controlling the supply of the AC power supply 6 to the heater 2, and 8 is a DC power supply unit for supplying a DC voltage to each unit. Reference numeral 9 denotes a transistor whose base is grounded, and the emitter is connected to the detection electrode line 4 (for example, see Patent Document 1). Reference numeral 10 denotes a temperature signal unit which converts a current flowing through the collector of the transistor 9 into a voltage and outputs a signal VT. A temperature setting unit 11 outputs a temperature setting signal Vs for the heater 2. Reference numeral 12 denotes a temperature control unit that compares the signal VT of the temperature signal unit 10 with the signal Vs of the temperature setting unit 11, and outputs a Hi output when the temperature of the heater 2 is lower than the setting, that is, when VT> Vs. The power control element 7 is driven. The signal VT of the temperature signal section 10 shows a high value when the temperature of the heater 2 is low and the impedance of the temperature sensor 3 is large because the current flowing through the collector of the transistor 9 is small. Conversely, when the temperature of the heater 2 increases and the impedance of the temperature sensor 3 decreases, the current flowing through the collector of the transistor 9 increases, and thus the value becomes low. By detecting the signal VT of the temperature signal section 10, the temperature of the heater 2 is controlled to a certain set temperature. Reference numeral 13 denotes a diode for guaranteeing the breakdown voltage between the emitter and the base of the transistor 9 and for flowing the current of the temperature sensor 3 on the positive cycle side of the AC power supply 6.
[0004]
[Patent Document 1]
JP-A-08-145388 (FIG. 1)
[0005]
[Problems to be solved by the invention]
However, in the conventional configuration, when the circuit is a one-chip integrated circuit, a parasitic operation occurs. The operation will be described with reference to FIG. In the figure, the signal current Is flowing through the temperature sensor 3 has a phase corresponding to the capacitance of the impedance of the temperature sensor 3, and most of the signal current Is at the high temperature side, with respect to the AC power supply 6 (Vac). You will be traveling close to 90 °. The temperature signal section 10 detects the current on the negative cycle side of the signal current Is. Therefore, the detection current of the temperature signal unit 10 is from the b side of the AC power supply 6 (Vac), from the base of the transistor 9 to the emitter, the detection electrode wire 4, the temperature sensor 3, the heater 2, and the a side of the AC power supply 6 (Vac). When the transistor 9 turns on, most of the detection current flows through the collector of the transistor 9. Then, the voltage is converted into a DC voltage signal VT by the resistor 14 and the capacitor 15 of the temperature detecting unit 10. At this time, the emitter potential Vb of the transistor 9 becomes more negative than the reference voltage GND of the circuit.
[0006]
When the circuit is configured by a one-chip integrated circuit, the negative voltage causes a parasitic operation that causes an abnormal circuit inside the integrated circuit. The output of the temperature control unit 12 becomes Hi output due to the influence of the circuit generated by the parasitic operation, and as shown by the voltage Vscr between the anode and the cathode of the power control element 7, the power control element 7 In the positive cycle of Vac), and in the negative cycle of the signal current Is, an abnormal operation of turning on continuously occurs. Due to this abnormal operation, the temperature of the heater 2 continues to rise, resulting in a very dangerous state.
[0007]
The present invention solves the above-mentioned conventional problems, and facilitates integration of a circuit using a temperature sensor exhibiting an impedance characteristic composed of a capacitance component and a resistance component integrally formed with a heater such as an electric carpet and an electric blanket. Accordingly, an object of the present invention is to provide a planar heating device having a control controller effective in terms of cost and mounting.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the planar heating device of the present invention connects the base to the ground point side of the AC power supply and the DC power supply unit, connects the emitter to the detection electrode wire side, and is determined by the impedance of the temperature sensor. An emitter of a transistor that allows a current to flow to a collector is provided with a current blocking portion that does not allow a signal current of a temperature sensor to flow during a positive cycle side of an AC power supply. The current blocking section always sets the emitter potential of the transistor to a positive potential during the positive cycle of the AC power supply.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the first aspect of the present invention, the base of the AC power supply and the DC power supply unit is connected to the ground point side, the emitter is connected to the detection electrode line side, and the emitter of the transistor that flows the current determined by the impedance of the temperature sensor to the collector is By configuring the current blocking portion for flowing a current in a direction for canceling the current flowing through the emitter during the positive cycle side of the AC power supply, the emitter potential can be always kept positive during the positive cycle period of the AC power supply.
[0010]
The invention according to claim 2 provides a current blocking section that increases the impedance between the sensing electrode line and the emitter of the transistor, particularly during the positive cycle side of the AC power supply, so that the emitter potential is reduced. It is possible to prevent the potential from becoming a negative potential during the positive cycle period of the power supply.
[0011]
According to the third aspect of the present invention, in particular, during the positive cycle side of the AC power supply, a current blocking portion for short-circuiting the base and the emitter of the transistor is formed, so that the emitter potential becomes negative during the positive cycle period of the AC power supply. The potential can be prevented.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to FIGS. The same parts as those in the conventional example are given the same numbers, and the operations are the same, so that the description will be omitted.
[0013]
(Example 1)
FIG. 1 shows a configuration diagram of a planar heating device according to a first embodiment of the present invention. In FIG. 1, reference numeral 21 denotes a current blocking unit which includes a diode 22 and a resistor 23, and cancels a current flowing through the emitter of the transistor 9 during a positive cycle in which the a side of the AC power supply 6 (Vac) has a positive potential. Apply current in the direction. Next, in the characteristic diagram of FIG. 2, the relationship between the current and the voltage of each section will be described with reference to the waveform of the AC power supply 6 (Vac).
[0014]
First, the signal current Is flowing through the temperature sensor 3 has the phase of 90 degrees with respect to the AC power supply 6 (Vac) because the impedance of the temperature sensor 3 is constituted by the capacitance, and especially on the high temperature side, almost becomes the capacitance. ° The current has advanced near. The current Ia flowing through the current blocking unit 21 has the same phase as that of the AC power supply 6 (Vac), and flows only during the positive cycle in which the a side of the AC power supply 6 (Vac) has a positive potential. Therefore, the current It flowing to the emitter of the transistor 9 is a combined current of the signal current Is flowing to the temperature sensor 3 and the current Ia flowing to the current blocking unit 21.
[0015]
Here, by setting the value of the current Ia flowing through the current blocking unit 21 to be larger than the value of the signal current Is flowing through the temperature sensor 3, a period of the positive cycle in which the a side of the AC power supply 6 (Vac) has a positive potential period. In this case, the current on the negative side of the current It flowing to the emitter of the transistor 9 can be canceled, and the current It becomes positive during the positive cycle in which the a side of the AC power supply 6 (Vac) has a positive potential. It becomes a current. Therefore, the emitter potential Vb of the transistor 9 is also always positive during the positive cycle in which the a side of the AC power supply 6 (Vac) has a positive potential. Therefore, even when an integrated circuit is formed, no parasitic operation occurs, and as shown by the waveform Vscr between the anode and the cathode of the power control element 7, the power control element 7 can be reliably turned off when it should be turned off.
[0016]
(Example 2)
FIG. 3 and FIG. 4 show a configuration diagram and a characteristic diagram of a planar heating device according to a second embodiment of the present invention. In FIG. 3, reference numeral 31 denotes a current blocking unit, which comprises a phototriac coupler 32 and a resistor 33. Next, the operation will be described with reference to FIG. No current flows to the LED section 34 of the phototriac coupler 32 of the current blocking section 31 during the positive cycle period in which the a-side of the AC power supply 6 (Vac) has a positive potential, and thus the phototriac coupler does not emit light. The triac unit 32 is turned off. Then, during a negative cycle period in which the a side of the AC power supply 6 (Vac) has a negative potential, a current flows through the LED unit 34 to emit light, and the triac unit 35 is turned on. Therefore, the signal current Is flowing through the temperature sensor 3 does not flow as a negative current during the positive cycle of the AC power supply 6 (Vac), and the emitter current It of the transistor 9 has a negative potential on the a side of the AC power supply 6 (Vac). Will flow only during the negative cycle. Therefore, the emitter potential Vb of the transistor 9 becomes negative only during the negative cycle in which the a side of the AC power supply 6 (Vac) is negative, and the negative potential can be prevented during the positive cycle. At this time, no parasitic operation occurs, and as shown by the waveform Vscr between the anode and the cathode of the power control element 7, it can be surely turned off when it should be turned off.
[0017]
(Example 3)
FIGS. 5 and 6 show a configuration diagram and a characteristic diagram of the planar warming device in the third embodiment of the present invention. In FIG. 5, reference numeral 41 denotes a current blocking unit, which comprises a phototransistor coupler 42 and a resistor 43. Next, the operation will be described with reference to FIG. A current flows through the LED section 44 of the phototransistor coupler 42 of the current blocking section 41 during the positive cycle period in which the a side of the AC power supply 6 (Vac) has a positive potential, so that the LED section 44 emits light and emits a phototransistor. The transistor section 45 of the coupler 42 is turned on.
[0018]
During a negative cycle period in which the a side of the AC power supply 6 (Vac) has a negative potential, no current flows to the LED unit 44 and no light is emitted, so the transistor unit 45 is turned off. Therefore, the current in the negative cycle side of the signal current Is flowing through the temperature sensor 3 during the positive cycle of the AC power supply 6 (Vac) flows as the current Ic of the transistor unit 45, and therefore, the signal current flowing through the temperature sensor 3 With the current on the negative cycle side of Is, only the current during the negative cycle of the AC power supply 6 (Vac) flows as the emitter current It of the transistor 9. Therefore, the emitter potential Vb of the transistor 9 becomes negative only during the negative cycle in which the a side of the AC power supply 6 (Vac) is negative, and the negative potential can be prevented during the positive cycle. At this time, no parasitic operation occurs, and as shown by the waveform Vscr between the anode and the cathode of the power control element 7, it can be surely turned off when it should be turned off.
[0019]
【The invention's effect】
As described above, according to the present invention, the base of the AC power supply and the DC power supply unit are connected to the ground point side, the emitter is connected to the detection electrode line side, and the emitter of the transistor that allows the current determined by the impedance of the temperature sensor to flow to the collector. In addition, by providing a current blocking portion that does not allow the signal current of the temperature sensor to flow during the positive cycle side of the AC power supply, a circuit configuration can be provided in which the emitter potential of the transistor does not become a negative potential during the positive cycle period of the AC power supply. Therefore, it is possible to provide a planar heating device having a control controller having a small number of components and a low cost, and having a small mounting space, since a parasitic operation does not occur and the circuit is easily integrated into a circuit. You can do it.
[Brief description of the drawings]
1 is a configuration diagram of a planar warming device according to a first embodiment of the present invention; FIG. 2 is a characteristic diagram of the planar warming device according to a first embodiment of the present invention; FIG. 3 is a second embodiment of the present invention; FIG. 4 is a configuration diagram of a planar warming device according to a second embodiment of the present invention. FIG. 5 is a configuration diagram of a planar warming device according to a third embodiment of the present invention. 6 is a characteristic diagram of a planar warming device according to a third embodiment of the present invention. FIG. 7 is a structural diagram of a heater integrated with a temperature sensor and a detection electrode wire. FIG. 8 is a characteristic diagram of a temperature sensor. Configuration diagram of conventional planar heating device [FIG. 10] Characteristic diagram of conventional planar heating device [Description of symbols]
2 Heater 3 Temperature sensor 4 Detection electrode wire 6 AC power supply 7 Power control element 8 DC power supply 9 Transistor 10 Temperature signal unit 11 Temperature setting unit 12 Temperature control unit 13 Diodes 21, 31, 41 Current blocking unit

Claims

An AC power supply, a heater disposed on the heater body, a detection electrode line integrally formed with the heater, and a temperature sensor exhibiting impedance characteristics including a capacitance component and a resistance component provided between the heater and the detection electrode line. A power control element that supplies power on the positive cycle side of the AC power supply to the heater; a DC power supply unit that rectifies the AC power supply to obtain a DC voltage; and a ground point side of the AC power supply and the DC power supply unit. A transistor having a base connected thereto and an emitter connected to the sensing electrode line side, a temperature signal section which converts a current determined by the impedance of the temperature sensor flowing through the collector of the transistor into a DC voltage to obtain a temperature signal, and the heater A temperature setting unit that sets the temperature of the temperature control unit, a signal from the temperature detection unit and a signal from the temperature setting unit are compared, and a control signal is output to the power control element. A diode connected in parallel with and opposite to the base and the emitter of the transistor, and a current blocking unit for flowing a current in a direction to cancel a current flowing to the emitter of the transistor during a positive cycle side of the AC power supply. Planar heating device.

The planar heater according to claim 1, further comprising a current blocking portion for increasing an impedance between the sensing electrode line and the emitter of the transistor during a positive cycle side period of the AC power supply.

The planar heater according to claim 1, further comprising a current blocking portion for short-circuiting the base and the emitter of the transistor during the positive cycle side of the AC power supply.