JP2006164924A

JP2006164924A - Discharge lamp lighting device

Info

Publication number: JP2006164924A
Application number: JP2004382291A
Authority: JP
Inventors: Takayuki Maruyama; 孝享丸山; Shinichi Nagao; 進一長尾
Original assignee: Hitachi Lighting Ltd
Current assignee: Hitachi Lighting Ltd
Priority date: 2004-12-03
Filing date: 2004-12-03
Publication date: 2006-06-22

Abstract

<P>PROBLEM TO BE SOLVED: To conduct control so that temperature rise of an inverter is restricted in the case that ambient temperature of a discharge lamp is high. <P>SOLUTION: A switching element 61 is provided between a reverse input terminal OPIN- of IC 20 for drive and a negative electrode terminal of a DC power source 1 and a temperature detection circuit 62 is provided to detect the ambient temperature of the discharge lamp 34 and to switch on/off the switching element 61. In the case that the ambient temperature of the discharge lamp rises to a high temperature, the switching element 61 is turned on, and electric power control is stopped. In the case that the ambient temperature of the discharge lamp becomes equal to or lower than room temperature, the switching element 61 is turned off and the electric power control is conducted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、数種類の放電灯を点灯することができる放電灯点灯装置に関するものである。特にその電力制御に関するものである。 The present invention relates to a discharge lamp lighting device capable of lighting several types of discharge lamps. In particular, it relates to the power control.

従来汎用の放電灯点灯装置を図２を用いて説明する。図２回路は、周波数可変形の高周波電圧を出力するインバータを備える。前記インバータは直流電源１を備え、順直列一対のスイッチング素子４１・４２を備え、前記スイッチング素子４１・４２をドライブするドライブ用ＩＣ２０を備え、前記スイッチング素子４１・４２の接続交点に接続されるコンデンサ３１、バラスト用インダクタ３２、共振用コンデンサ３３からなる直列共振回路を備え、前記共振用コンデンサ３３に並列接続される放電灯３４を備える。
前記ドライブ用ＩＣ２０は発振器２１を内蔵する。該発振器２１の出力周波数は、周波数設定コンデンサ接続端子ＣＦに接続される周波数設定コンデンサ５７と周波数設定抵抗接続端子ＲＩＮＧに接続される周波数設定抵抗５８で決定される。さらに前記ドライブ用ＩＣ２０はオペアンプ２２を内蔵する。該オペアンプ２２の反転入力端子ＯＰＩＮ−と出力端子ＯＰＯＵＴ間に接続されるコンデンサ５１を備え、前記周波数設定抵抗接続端子ＲＩＮＧと前記出力端子ＯＰＯＵＴ間に接続される直列接続されたダイオード５２と抵抗５３を備え、前記反転入力端子ＯＰＩＮ−と前記スイッチング素子４２のソース端子間に接続される抵抗５４を備え、前記スイッチング素子４２のソース端子と直流電源１の負極端子間に接続される電流検出用抵抗５５を備える。
前記ドライブ用ＩＣ２０は予熱時間設定端子ＣＰＲＥと予熱周波数設定端子ＲＰＲＥを備え、前記予熱時間設定端子ＣＰＲＥに接続される予熱時間設定コンデンサ５９を備え、前記予熱周波数設定端子ＲＰＲＥに接続されるランプ電流調整用半固定抵抗５６を備える。前記ランプ電流調整用半固定抵抗５６の中点端子は非反転入力端子ＯＰＩＮ＋に接続される。
図２回路の回路動作について説明する。直流電源１に流れる入力電流を電流検出用抵抗５５で検出し、電流検出用抵抗５５電圧が抵抗５４を介してオペアンプ２２の反転入力端子ＯＰＩＮ−に印加される。該反転入力端子ＯＰＩＮ−電圧がランプ電流調整用半固定抵抗５６で決定される非反転入力端子ＯＰＩＮ＋電圧より低い場合は、出力端子ＯＰＯＵＴには周波数設定抵抗端子ＲＩＮＧ電圧より高い電圧が発生するためダイオード５２、抵抗５３は遮断され、放電灯３４は周波数設定コンデンサ５７と周波数設定抵抗５８で決定される周波数で点灯する。該反転入力端子ＯＰＩＮ−電圧がランプ電流調整用半固定抵抗５６で決定される非反転入力端子ＯＰＩＮ＋電圧より高い場合は、出力端子ＯＰＯＵＴに電圧は発生しない。この場合、周波数設定抵抗接続端子ＲＩＮＧには周波数設定抵抗５８と並列に抵抗５３が接続される。この時、放電灯３４は非反転入力端子ＯＰＩＮ＋電圧と反転入力端子ＯＰＩＮ−電圧が等しくなるようなランプ電流が流れるように制御され、負荷に関わらず負荷電力が一定となるように制御される。
一般に放電灯３４、例えば蛍光ランプは高温や低温では室温よりランプ電圧が下がる特性がある。放電灯３４の周囲温度が高温になると、ランプ電流が増え、インバータの損失が多くなり、温度が高くなることが懸念される。A conventional general-purpose discharge lamp lighting device will be described with reference to FIG. The circuit shown in FIG. 2 includes an inverter that outputs a frequency-variable high-frequency voltage. The inverter includes a DC power source 1, a pair of forward-series switching elements 41 and 42, a drive IC 20 that drives the switching elements 41 and 42, and a capacitor connected to a connection intersection of the switching elements 41 and 42. 31 includes a series resonance circuit including a ballast inductor 32 and a resonance capacitor 33, and a discharge lamp 34 connected in parallel to the resonance capacitor 33.
The drive IC 20 incorporates an oscillator 21. The output frequency of the oscillator 21 is determined by the frequency setting capacitor 57 connected to the frequency setting capacitor connection terminal CF and the frequency setting resistor 58 connected to the frequency setting resistor connection terminal RING. Further, the drive IC 20 includes an operational amplifier 22. The operational amplifier 22 includes a capacitor 51 connected between the inverting input terminal OPIN− and the output terminal OPOUT, and includes a diode 52 and a resistor 53 connected in series connected between the frequency setting resistor connection terminal RING and the output terminal OPOUT. A resistor 54 connected between the inverting input terminal OPIN− and the source terminal of the switching element 42, and a current detection resistor 55 connected between the source terminal of the switching element 42 and the negative terminal of the DC power supply 1. Is provided.
The drive IC 20 includes a preheating time setting terminal CPRE and a preheating frequency setting terminal RPRE, a preheating time setting capacitor 59 connected to the preheating time setting terminal CPRE, and a lamp current adjustment connected to the preheating frequency setting terminal RPRE. A semi-fixed resistor 56 is provided. The midpoint terminal of the lamp current adjusting semi-fixed resistor 56 is connected to the non-inverting input terminal OPIN +.
The circuit operation of the circuit of FIG. 2 will be described. An input current flowing through the DC power source 1 is detected by the current detection resistor 55, and the current detection resistor 55 voltage is applied to the inverting input terminal OPIN− of the operational amplifier 22 via the resistor 54. When the inverting input terminal OPIN− voltage is lower than the non-inverting input terminal OPIN + voltage determined by the lamp current adjusting semi-fixed resistor 56, a voltage higher than the frequency setting resistance terminal RING voltage is generated at the output terminal OPOUT. 52 and the resistor 53 are cut off, and the discharge lamp 34 is lit at a frequency determined by the frequency setting capacitor 57 and the frequency setting resistor 58. When the inverting input terminal OPIN− voltage is higher than the non-inverting input terminal OPIN + voltage determined by the lamp current adjusting semi-fixed resistor 56, no voltage is generated at the output terminal OPOUT. In this case, a resistor 53 is connected in parallel with the frequency setting resistor 58 to the frequency setting resistor connection terminal RING. At this time, the discharge lamp 34 is controlled so that a lamp current flows so that the non-inverting input terminal OPIN + voltage and the inverting input terminal OPIN− voltage are equal, and the load power is controlled to be constant regardless of the load.
In general, the discharge lamp 34, for example, a fluorescent lamp, has a characteristic that the lamp voltage decreases from room temperature at high and low temperatures. When the ambient temperature of the discharge lamp 34 becomes high, there is a concern that the lamp current increases, the loss of the inverter increases, and the temperature increases.

本発明の目的は、放電灯の周囲温度が高温の場合においても、インバータの温度上昇を抑えるように制御することにある。 An object of the present invention is to control the temperature rise of the inverter to be suppressed even when the ambient temperature of the discharge lamp is high.

前記ドライブ用ＩＣ２０の前記反転入力端子ＯＰＩＮ−と前記直流電源１の負極端子間にスイッチング素子６１を備え、前記放電灯３４の周囲温度を検知して前記スイッチング素子６１をオン／オフさせる温度検知回路６２を備える。
この回路において、放電灯周囲温度が高温になった時に、前記スイッチング素子６１をオンし、電力制御を停止させ、放電灯周囲温度が室温以下になった時に、前記スイッチング素子６１をオフし、電力制御を行う。A temperature detection circuit that includes a switching element 61 between the inverting input terminal OPIN− of the drive IC 20 and the negative terminal of the DC power supply 1 and detects the ambient temperature of the discharge lamp 34 to turn on / off the switching element 61. 62.
In this circuit, when the discharge lamp ambient temperature becomes high, the switching element 61 is turned on, power control is stopped, and when the discharge lamp ambient temperature falls below room temperature, the switching element 61 is turned off, Take control.

本発明によれば、放電灯の周囲温度が高温の状態では電力制御を止め、インバータの温度の上昇を抑えることができ、放電灯の周囲温度が低温の状態では電力制御をすることで、電力低下を防ぎ、明るさの低下を抑えることができる。 According to the present invention, power control can be stopped when the ambient temperature of the discharge lamp is high, and the rise in the inverter temperature can be suppressed, and power control can be performed when the ambient temperature of the discharge lamp is low. It is possible to prevent a decrease and to suppress a decrease in brightness.

図１を用いて本発明の実施形態について説明する。前記従来と同一部分については説明を省略する。図１は従来の回路図２に対してドライブ用ＩＣ２０の反転入力端子ＯＰＩＮ−と直流電源１の負極端子間にスイッチング素子６１を備え、放電灯３４の周囲温度を検知して前記スイッチング素子６１をオン／オフさせる温度検知回路６２を備える回路である。
前記温度検知回路６２は放電灯周囲温度が高温になると、前記スイッチング素子６１をオンさせる。前記スイッチング素子６１がオンすることにより、前記ドライブ用ＩＣ２０の反転入力端子ＯＰＩＮ−電圧は非反転入力端子ＯＰＩＮ＋電圧より低くなり、出力端子ＯＰＯＵＴは周波数設定抵抗端子ＲＩＮＧ電圧より高い電圧が発生するためダイオード５２、抵抗５３は遮断され、放電灯３４は周波数設定コンデンサ５７と周波数設定抵抗５８で決定される周波数、すなわち電力制御をしていない高い周波数で点灯する。かくして、前記周囲温度が所定値を超えたとき定電力制御手段を停止させ前記ランプ電力を制限する。
このように、ランプの周囲温度が上昇すると、インバータは一定の高い周波数（電流）で発振するため、温度上昇を抑えることができる。
放電灯周囲温度が低温の場合には、前記スイッチング素子６１をオフするように前記温度検知回路６２が働き、従来の技術と同様に電力制御を行い、ランプ電流（明るさ）を低下させることなく放電灯を点灯させることができる。An embodiment of the present invention will be described with reference to FIG. The description of the same parts as those in the prior art is omitted. 1 includes a switching element 61 between the inverting input terminal OPIN− of the driving IC 20 and the negative terminal of the DC power supply 1 as compared with the conventional circuit diagram 2, and detects the ambient temperature of the discharge lamp 34 to detect the switching element 61. This circuit includes a temperature detection circuit 62 that is turned on / off.
The temperature detection circuit 62 turns on the switching element 61 when the discharge lamp ambient temperature becomes high. When the switching element 61 is turned on, the inverting input terminal OPIN− voltage of the driving IC 20 becomes lower than the non-inverting input terminal OPIN + voltage, and the output terminal OPOUT generates a voltage higher than the frequency setting resistance terminal RING voltage. 52 and the resistor 53 are cut off, and the discharge lamp 34 is lit at a frequency determined by the frequency setting capacitor 57 and the frequency setting resistor 58, that is, at a high frequency without power control. Thus, when the ambient temperature exceeds a predetermined value, the constant power control means is stopped to limit the lamp power.
As described above, when the ambient temperature of the lamp rises, the inverter oscillates at a constant high frequency (current), so that the temperature rise can be suppressed.
When the ambient temperature of the discharge lamp is low, the temperature detection circuit 62 works to turn off the switching element 61 and performs power control in the same manner as in the prior art without reducing the lamp current (brightness). The discharge lamp can be turned on.

本発明に係る放電灯点灯装置の回路図である。1 is a circuit diagram of a discharge lamp lighting device according to the present invention. 従来の放電灯点灯装置の回路図である。It is a circuit diagram of the conventional discharge lamp lighting device.

Explanation of symbols

１：直流電源
２０：ドライブ用ＩＣ
３１：コンデンサ
３２：バラスト用インダクタ
３３：共振用コンデンサ
３４：放電灯
４１・４２：スイッチング素子
４２：リセット手段
５６：ランプ電流調整用半固定抵抗
６１：制御用スイッチング素子
６２：ランプ周囲温度検出回路1: DC power supply 20: IC for drive
31: Capacitor 32: Ballast inductor 33: Resonance capacitor 34: Discharge lamp 41, 42: Switching element 42: Reset means 56: Lamp current adjusting semi-fixed resistor 61: Control switching element 62: Lamp ambient temperature detection circuit

Claims

A discharge lamp, an inverter for supplying high-frequency power to the discharge lamp, a control circuit for controlling the inverter, the control circuit being fixed even when the discharge lamps having different tube voltages are connected Constant power control means for supplying lamp power, temperature detection means for detecting the ambient temperature of the discharge lamp, and stopping the constant power control means when the ambient temperature exceeds a predetermined value, A discharge lamp lighting device comprising means for limiting.