JPH0261118B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a discharge lamp lighting device that can switch the output of a discharge lamp between a full lighting state and a dimmed lighting state.

[Background Art] Conventionally, as a discharge lamp lighting device, as shown in FIG. 6 and FIG. Inverter circuit 3 that performs oscillation
The discharge lamp 4 is controlled by controlling the output of the inverter circuit 3.
A light control circuit 5 for controlling the light is provided. A power switch 6' is inserted between the AC power supply 1 and the rectifying and smoothing circuit 2, and a dimming changeover switch 7 is inserted between the output end of the rectifying and smoothing circuit 2 and the dimming control circuit 5. . That is, when the dimmer changeover switch 7 is in the OFF state, power is not supplied to the dimmer control circuit 5, so the discharge lamp 4 is lit 100%, and when the dimmer changeover switch 7 is in the ON state, the dimmer control circuit 5 is activated. Thus, the discharge lamp 4 is dimmed and turned on. In such a configuration, since two operation switches, the power switch 6' and the dimming changeover switch 7, are required, the problem is that the space occupied is large and the operation is troublesome. Furthermore, if it is attempted to interlock the power switch 6' and the dimming changeover switch 7, which are separate units, in order to improve operability, a problem arises in that the interlocking mechanism becomes complicated.

[Object of the Invention] The present invention has been made in view of the above points, and its main purpose is to enable a single switch to function as both a power switch and a dimming switch. An object of the present invention is to provide a discharge lamp lighting device with improved performance.

[Disclosure of the Invention] (Structure) A discharge lamp lighting device according to the present invention includes: an inverter circuit that outputs a high-frequency voltage in response to current and a voltage of the power source; a discharge lamp that lights up in response to the high-frequency voltage; a power supply contact section inserted between the power supply and the inverter circuit to turn on and off the power input to the inverter circuit; a dimming control circuit that receives the voltage of the power supply and controls the output of the inverter circuit; A dimming switching contact that is inserted between the power supply and the dimming control circuit and switches the output of the discharge lamp between the full lighting state and the dimming lighting state by turning on and off the power input to the dimming control circuit. and a power supply contact part and a dimming control circuit so that the dimming control circuit can be turned on and off by the dimming switching contact part only when the power supply contact part is closed. It is equipped with a changeover switch that can be operated with a single operator, with a power contact that turns on and off the power to the inverter, and a dimmer that turns on and off the power to the dimming control circuit. The switch is equipped with a switching contact section and a switch that operates both the power supply contact section and the dimming switching contact section using one operator, so only one switch is required to switch on the power supply. It is possible to turn on/off and switch on/off the lighting state, which occupies less space and makes the overall configuration more compact.
This makes it possible to improve operability without requiring a complicated mechanism that would be required for interlocking individual switches.

Embodiment 1 As shown in FIG. 1, the basic configuration is the same as the conventional one, and includes a rectifier circuit 8 that rectifies an AC power source 1, an inverter circuit 3 that performs high-frequency oscillation using the output of the rectifier circuit 8 as a power source, and an inverter circuit. 3, and a dimming control circuit 5 that controls the output of the inverter circuit 3 to switch the discharge lamp 4 between a full lighting state and a dimmed lighting state.

The rectifier circuit 8 is a bridge rectifier circuit consisting of four diodes D ₁ to D ₄ , and a smoothing capacitor C ₁ is connected between both output terminals to form the rectifier and smoothing circuit 2 .
is configured.

As shown in FIG. 2, the inverter circuit 3 is driven by a DC power source E, and the output of the rectifying and smoothing circuit 2 corresponds to this. This inverter circuit 3 is a series resonant inverter circuit, and a series circuit of a pair of transistors Q ₁ and Q ₂ is connected to a DC power source E.
Diodes D ₅ and D ₆ are connected in antiparallel between the collector and emitter of each transistor Q ₁ and Q ₂ , respectively. In addition, a discharge lamp 4 and a capacitor C ₃ are connected between the collector and emitter of one transistor Q ₁ .
A resonant circuit 10 in which a capacitor C ₄ and a chiyoke coil L are connected in series in a parallel circuit with the drive transformer
A series circuit of the primary winding n ₁₁ of T ₁ and the primary winding n ₂₁ of current transformer T ₂ is connected. Also,
A preheating switch SW is connected to the discharge lamp 4. The drive transformer T ₁ includes a pair of secondary windings n ₁₂ and n ₁₃ ,
One end of each of the secondary windings n ₁₂ and n ₁₃ is connected to the base of each transistor Q ₁ and Q ₂ , respectively. That is, the secondary windings n ₁₂ and n ₁₃ of the drive transformer T ₁ are used as feedback windings. Inverter circuit 3 has a resistor
A starting circuit 9 is provided which includes _R3 , a capacitor _C5 , and a trigger element Z such as a diagonal. resistance
R ₃ and capacitor C ₅ are connected in series, both ends of this series circuit are connected to DC power supply E, and one end of trigger element Z is connected to the connection point between both elements. The other end of the trigger element Z is connected to the base of one transistor _Q2 . A transistor _Q3 is connected between the base and emitter of one transistor _Q2 , and one end of the secondary winding _n22 of the current transformer _T2 is connected to the base of the transistor _Q3 via a diode _D7 . Furthermore, a transistor for dimming switching is connected between the base and emitter of transistor _Q3 .
_Q4 is connected, and the inverting circuit 11 is connected to the base of transistor _Q4 .

The operation of this inverter circuit 3 will be explained below. First, when the DC power supply E is connected, the resistance
Capacitor _C5 is charged via _R3 . When the terminal voltage of capacitor _C5 reaches the breakover voltage of trigger element Z, the charge of capacitor _C5 is discharged via the base-emitter junction of transistor _Q2 . This discharge current causes the transistor to
Since Q ₂ is turned on, current flows in the loop of DC power supply E → resonant circuit 10 → drive transformer T ₁ primary winding n ₁₁ → transistor Q ₂ → DC power supply E,
The capacitor _C4 forming the resonant circuit 10 is charged. This charging current is applied to the primary winding of drive transformer _T1 .
Since the current flows through n ₁₁ , an induced voltage is generated in the secondary windings n ₁₂ and n ₁₃ , and this induced voltage flows through the transistor
The polarity is set to keep Q ₂ on.
Once capacitor _C4 is charged, the drive transformer
The induced voltage of T ₁ is inverted, transistor Q ₁ is turned on, and transistor Q ₂ is turned off. In this state, a closed loop is formed by the primary winding _n11 of the drive transformer _T1 , the transistor _Q1 , and the resonant circuit 10, so the capacitor _C4 is discharged, and the voltage induced in the drive transformer _T1 due to this discharge current causes the transistor Q ₁ remains on. As the discharge progresses, the induced voltage is reversed again, and from then on, both transistors Q ₁ and Q ₂ are alternately turned on and off.
A high frequency current flows through the resonant circuit 10 by repeating the off state, and the terminal voltage of the capacitor _C3 is applied to the discharge lamp 4, thereby lighting the discharge lamp 4.

Next, the switching operation between the full lighting state and the dimming lighting state will be explained. Transistor _Q4 for dimming control
When is in the on state, the transistor _Q3 is in the off state, so the above operation is performed, and as shown in FIG.
As shown in the figure, both transistors Q ₁ and Q ₂ oscillate at a constant frequency so that the on period is approximately equal, and a fully lit state is achieved. On the other hand, when the dimming control transistor _Q4 is turned off, the oscillation cycle is shortened by the following operation. That is, during the on-period of the transistor _Q2 , the polarity of the voltage induced in the secondary winding _n22 of the current transformer _T2 is in the forward direction with respect to the diode _D7 , so the transistor _Q3 is turned on. This turns transistor _Q2 off. As a result, as shown in FIG. 3b, the on period of the transistor _Q2 becomes shorter than in the fully lit state, and the oscillation frequency becomes higher. Therefore, the impedance of the inductive load such as the chiyoke coil L becomes high, resulting in a dimmed lighting state.

The inverter circuit 3 is set to the full lighting state and the dimming lighting state in accordance with the on state and off state of the transistor _Q4 as described above.
Since the inverting circuit 11 is connected to the base of the transistor _Q4 , when a dimming switching signal that is positive with respect to the ground side of the inverter circuit 3 is input as an input signal to the inverting circuit 11, the dimming control is performed. The transistor _Q4 is turned off and the dimmed lighting state is entered. The dimming control circuit 5 is the inverter circuit 3
The dimming control circuit 5 is designed to generate a dimming switching signal that is positive with respect to the ground side of the dimming control circuit 5 when power is supplied to the control terminal. Power is supplied to the dimming control circuit 5 via the changeover switch 6 in the following manner. That is, the changeover switch 6 has a configuration equivalent to a general pull switch used in lighting equipment, and has six fixed contacts arranged at equal intervals on the circumference, as shown in FIG. It is constituted by a rotary switch including r ₁ to _{r 6} and a rotatable movable contact q that short-circuits two fixed contacts r ₁ to _{r 6} facing each other. The movable contact q is rotatably operated by an operator such as an operating string or an operating handle, and is connected to the AC power source 1, and is connected to an adjacent pair of fixed contacts r among the fixed contacts _r1 to _r6 . ₁ and _r2 are connected to one input end of the rectifying and smoothing circuit 2, and together with the movable contact q, form a power supply contact portion for turning on and off the power supply to the inverter circuit 3 and the dimming control circuit 5. _{A fixed contact r5 facing one fixed contact r2 of both fixed contacts r1 and r2 is connected to} the power supply part of the dimming control circuit 5 via a resistor _R2 . That is, the fixed contact r ₅ together with the movable contact q forms a dimming switching contact portion that turns on/off the continuation of power supply to the control terminal of the dimming control circuit 5 . The remaining fixed contacts r ₃ , r ₄ , and r ₆ are not connected to anything. The above resistor is connected between the fixed contact _R5 of the changeover switch 6 and the ground side output terminal of the rectifier and smoothing circuit 2.
A voltage dividing circuit made up of a series circuit of R ₂ and a resistor R ₁ is inserted, and _{a smoothing capacitor C 2 is} connected in parallel to the resistor R 1 . This capacitor C ₂
The power source for the dimming control circuit 5 is obtained from both ends of the dimming control circuit 5, and the dimming control circuit 5 is grounded to the output terminal on the ground side of the rectifying and smoothing circuit 2. When the movable contact q short-circuits the fixed contacts r ₂ and r ₅ , the potential of the fixed contact r ₅ seen from the ground side of the inverter circuit 3 is the same as that of the diode forming the rectifying bridge circuit 8.
Since it is equal to the potential difference between both ends of D ₁ , a voltage obtained by half-wave rectification of alternating current is applied as shown in _FIG . It is applied to the power supply section of In this way, when power is being supplied to the control terminal of the dimming control circuit 5, a dimming switching signal is obtained from the dimming control circuit 5, and the discharge lamp 4 is set to the dimming lighting state. In addition, the changeover switch 6
When the fixed contacts r ₁ and r ₄ are short-circuited by the movable contact q, power is not supplied to the dimming control circuit 5, so the discharge lamp 4 is fully lit, and the contacts are closed.
When the distance between r ₃ and r ₆ is shortened, the discharge lamp 4 is turned off. Here, a pull switch is used as the changeover switch 6, but it goes without saying that other types of switches can be used.

Embodiment 2 This embodiment uses a pair _of diodes D ₈ and D ₉ connected in series as shown in FIG.
A rectifier circuit 8 is constituted by a series circuit of a pair of capacitors C ₆ and C ₇ connected in parallel to a series circuit of D ₉ , and performs voltage doubler rectification. The changeover switch 6 has the same configuration as in the first embodiment, and its fixed contacts r ₄ and r ₅ are connected to the connection points of both capacitors C ₆ and C ₇ . Fixed contacts corresponding to fixed contacts r ₅
A voltage divider circuit in which a pair of resistors R ₁ and R ₂ are connected in series is inserted between r ₂ and the output terminal on the ground side of the rectifier circuit 8, and the dimming control circuit 5 is controlled from both ends of the resistor R ₁ . Power is being supplied to the terminal. Therefore, if the fixed contacts r ₂ and r ₅ are short-circuited by the movable contact q, power is supplied to the dimming control circuit 5.
As a result, the dimming control circuit 5 operates, a dimming switching signal is obtained, and the discharge lamp 4 enters the dimming lighting state. That is, the fixed contacts r ₄ and r ₅ function as power supply contacts, and the fixed contact r ₂ functions as a dimming control contact. Also, in this circuit, the power to the dimming control circuit 5 is obtained from both ends of the capacitor _C6 , so it has already been smoothed.
There is no need to provide a separate capacitor for smoothing, which simplifies the circuit configuration.

[Effects of the Invention] The present invention has the above configuration, and includes a power supply contact section for turning on and off the power to the inverter and a dimming switching contact section for turning on and off the power to the dimming control circuit. In addition, there is a changeover switch that operates both the power supply contact and the dimming switch with one operator, so you can turn the power on and off and change the lighting state with just one changeover switch. It is possible to realize both functions, occupy less space, make the overall configuration more compact, and improve operability without requiring a complicated mechanism such as when two switches are linked. It has the advantage of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing Embodiment 1 of the present invention;
Fig. 2 is a circuit diagram showing the inverter circuit used in the above, Fig. 3 is an explanatory diagram of the operation of the circuit shown in Fig. 2, Fig. 4 is an explanatory diagram of the operation of the first embodiment shown in Fig. 1, and Fig. 5 is an explanatory diagram of the operation of the circuit shown in Fig. 1. A block diagram showing a second embodiment of the present invention, and FIGS. 6 and 7 are block diagrams showing conventional examples, respectively. 1 is an AC power supply, 3 is an inverter circuit, 4 is a discharge lamp, 5 is a dimming control circuit, 6 is a changeover switch, 8 is a rectifier circuit, q is a movable contact, and r ₁ to _{r 6} are fixed contacts.

Claims (1)

[Claims] 1. A power source, an inverter circuit that receives the voltage of this power source and outputs a high-frequency voltage, a discharge lamp that lights up in response to this high-frequency voltage, and a voltage that is inserted between the power source and the inverter circuit and is input to the inverter circuit. A power supply contact section that turns on and off the power supply, a dimming control circuit that receives the voltage of the power supply and controls the output of the inverter circuit, and a dimming control circuit that is inserted between the power supply and the dimming control circuit. and a contact part for dimming switching that switches the output of the discharge lamp between a full lighting state and a dimmed lighting state by turning on and off the power input to the lamp, and the contact part for the power supply is closed. In order to turn on and off the power to the dimming control circuit using the dimming switching contact only in certain cases, the switch is equipped with a switch that operates both the power supply contact and the dimming switching contact with a single operator. A discharge lamp lighting device characterized by comprising: