JPH1140384A - Discharge lamp lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the period of time during which large stress is applied to a switching element having an inverter circuit when power supply from an AC power source is stopped. SOLUTION: A power source circuit 4 for supplying an operation power to a control circuit 3 is constituted with a resistance R1 , a zener diode ZD, a capacitor C4 , a diode D3 , and a current amount switching circuit 5. The current amount switching circuit 5 is constituted with a parallel circuit of a resistance R2 and a series circuit of a resistance R3 and a switch SW2 . During low load operation, the switch SW2 is turned on, current I2 necessary and sufficient to pre-heat and start is supplied, and during lighting, the switch SW2 is turned off, and the supply amount of the current I2 is reduced to a degree necessary and sufficient to keep lighting. The period of time from stopping of power supply from the commercial AC power source Vs to stopping of the operation of the control circuit 3 by a reset circuit is shortened to shorten the period of time during which large stress is applied to switching elements Q1 , Q2 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device.

[0002]

[Prior art]

(Conventional Example 1) FIG. 8 is a circuit diagram showing a conventional discharge lamp lighting device. Connect the commercial AC power source Vs through the main switch SW ₁ between AC input terminals of the diode bridge DB,
The commercial AC power supply Vs is full-wave rectified. A smoothing capacitor C ₆ , a diode D ₅ , and a diode D ₄ are sequentially connected in series between the DC output terminals of the diode bridge DB, and a capacitor C is connected between both ends of the diode D _5.
15 are connected in parallel. A series circuit of switching elements Q ₁ and Q ₂ composed of FETs is connected in parallel between both ends of the capacitor C ₆ . Here, a parasitic diode (not shown) is connected in anti-parallel to each of the switching elements Q ₁ and Q ₂ .

A capacitor C ₈ is connected between a connection point between the switching elements Q ₁ and Q _{2 and} a connection point between the diodes D ₄ and D _5.
A leakage transformer (hereinafter, simply referred to as "trans".) Series circuit of a primary winding n ₁ of T ₃ is is connected. This secondary winding n ₂ of the transformer T _3, the parallel circuit of the capacitor C ₉ as a load circuit discharge lamp La _1, La ₂ is is connected. Thus, the transformer T ₃ and the capacitor C
₉ and the discharge lamps La ₁ and La ₂ constitute the lighting resonance circuit 10.

The capacitor C₆Between both ends of the
Kuta L_ThreeAnd capacitor C_FiveAnd the card inserted in the opposite direction
Iod D₇Series circuits are connected in parallel and capacitors
C_FiveAnd diode D₇Connection point and switch with cathode
Element Q₁, Q_TwoDiode D between the₆To
Inserted in the forward direction. Thus, the switching element
Q _Two, Diode D₆, D₇, Capacitor C_FiveAnd
Nacta L_ThreeConstitutes a so-called step-down chopper circuit 9
I have.

Further, a capacitor C₈And transformer T_ThreeOf 1
Next winding n₁And the diode D_Five, D₇Contact with
Preheating transformer T between the continuation point_FourPrimary winding n_FourAnd con
Densa C₁₆Are connected in series. This preheating tiger
Once T_FourSecondary winding n_Five, N ₆, N₇Are conde
Sensor C₁₁, C₁₂, C₁₃Through the discharge lamp La₁, La_Twoof
Connected to the filament. Thus, the preheating transformer
T_FourAnd capacitor C₁₆Thus, the preheating resonance circuit 11 is configured.
Is done.

On the other hand, the capacitor C₆Between both ends of the resistor R
₁And Zener diode ZD₁And capacitor C₁₄of
A series circuit with a parallel circuit is connected, and a resistor R₁And conden
Sa C ₁₄Is connected to the control circuit 3. This system
The control circuit 3 is a switching element Q₁, Q_TwoAlternating with high frequency
Control for turning on and off the power supply. Also Tran
S_ThreeSecondary winding n_ThreeOne terminal to ground
Connected and the other terminal is diode D_FiveAnd resistance R_TwoThrough
And the resistance R₁And capacitor C₁₄To the connection point with
You. Thus, the resistance R₁, Zener diode ZD₁,
Capacitor C₁₄, Diode D_FiveAnd resistance R_TwoBy
Thus, a power supply circuit 12 for supplying operating power to the control circuit 3 is configured.
Is done.

Next, the basic operation of the above-described conventional device will be described separately for the operation of the inverter circuit 1 having a series circuit of the switching elements Q ₁ and Q ₂ and the operation of the step-down chopper circuit 9. First, the operation of the inverter circuit 1, turns on the switching element Q ₁ by the control circuit 3, when turning off the Q _2, the capacitor C ₆ → the switching element Q ₁ → capacitor C ₈ → transformer T to the capacitor C ₆ as a power source ₃ primary winding n ₁ → capacitor C ₁₅ →
The current flowing in the path of the capacitor C _6
15 is charged. Also, from the AC power supply Vs, the diode bridge DB → the switching element Q ₁ → the capacitor C ₈ →
A current flows through the path of the primary winding n ₁ of the transformer T ₃ → the diode D ₄ → the diode bridge DB. The condition under which the current flows is the sum of the voltage across the capacitor C _{6 and} the voltage across the capacitor C _15. , When it is lower than the DC output terminal voltage of the diode bridge DB.

On the other hand, the control circuit 3 by turning off the switching element Q _1, when turning on the Q ₂ are capacitor C
₁₅ → the discharge current of the capacitor C ₁₅ in the path of the primary winding n ₁ → capacitor C ₈ → the switching element Q ₂ → capacitor C ₁₅ of the transformer T ₃ flows, discharge is completed, the diode through a diode D ₅ D ₅ → A loop current flows through the path of the primary winding n ₁ of the transformer T ₃ → the capacitor C ₈ → the switching element Q ₂ → the diode D ₅ .

As described above, the switching elements Q ₁ and Q ₂ are alternately turned on and off by the control circuit 3,
To generate a high frequency voltage between the secondary winding of n ₂ across the transformer T _3, can be turned by supplying a high-frequency voltage to the discharge lamp La _1, La _2. Next, the step-down chopper circuit 9
Will be described. First (clear Q ₁₎ on the switching element Q ₂ by the control circuit 3 and a diode D
_{When 5} is conducting, the diode bridge DB
→ Inductor L ₃ → Capacitor C ₅ → Diode D ₆ →
Switching element Q ₂ → Diode D ₅ → Diode D
Capacitor C ₅ is charged by the current flowing in the path of the ₄ → the diode bridge DB. Switching Q ₂
There when the discharge current of the capacitor C ₁₅ is flowing is on, the capacitor C ₆ → inductor L ₃ → capacitor C ₅
→ Diode D ₆ → Switching element Q ₂ → Capacitor C ₅ is also charged by current flowing through the path of capacitor C ₆ .

On the other hand, the switching element Q_TwoIs off (Q₁
Is ON), the inductor L _Three→ Capacitor C_Five
→ Diode D₆→ Switching element Q₁Parasitic Daio
To inductor L_ThreeCurrent flows in the path of
L_ThreeIs released. like this
The switching element Q by the control circuit 3_TwoAt high frequency
By being turned on and off, the capacitor C_FiveOn both ends of
A step-down voltage is generated.

Next, the operation of the power supply circuit 12 will be described. The power supply in the power supply circuit 12 has two paths. First supplies a current I ₁ One is through the resistor R ₁ from the high potential side of the capacitor C ₆ is a DC voltage source
The current supply amount is determined according to the voltage Vc ₆ across the capacitor C ₆ .
The main role of the first source to charge the capacitor C ₁₄ to the control circuit 3 can be started, up to V _CC (supply voltage for the operation of the control circuit 3) the voltage across the capacitor C ₁₄ to a predetermined level It is to raise. Since the consumption current I ₃ of the control circuit 3 before starting is extremely small, the supply current I ₁
May be small.

The second is a path from a second supply source for supplying the current I ₂ from the secondary winding n ₃ of the transformer T ₃ via the diode D ₅ and the resistor R ₂ . The high frequency voltage Vn ₃ generated in the secondary winding n ₃ of the transformer T ₃ is half-wave rectified by the diode D ₅ . The high-frequency voltage Vn generated in the secondary winding n _3
3, the discharge lamp La via the secondary winding n ₂ of the transformer T _3
1 and La ₂ change in accordance with the voltage V _La applied thereto. The main role of the second source is to supply most of the current I ₃ which control circuit 3 is consumed by the control circuit 3 after starting. That is, after the control circuit 3 is activated, the second
Supply current from the supply source occupies most of the consumption current I ₃ in the control circuit 3.

[0013] Here, the control circuit 3 supply voltage monitoring circuit (hereinafter, referred to as "reset circuit".) Which detects the rising and falling of the power supply voltage V _CC is provided. The reset circuit includes a comparator CP, compares the reference voltage Vk generated in the control circuit 3 with the power supply voltage V _CC, and operates the control circuit 3 when Vk ≦ V _CC , where Vk> V _CC In the case of, the function of stopping the operation of the control circuit 3 is provided.

By the way, the discharge lamp La₁, La_TwoIs lit
If the power supply from the AC power supply Vs is stopped
If the main switch SW₁Is turned off)
Then, as shown in FIG.₁
Immediately after turning off the discharge lamp La ₁, La_TwoOrchids flowing in
Current I_LaBegins to decay. On the other hand, the lamp voltage V_LaIs orchid
Current I_LaConversely, it rises while decay. Also transformer
T_ThreeSecondary winding n_ThreeHigh-frequency voltage Vn_ThreeIs a lamp
Voltage V_LaSupply to the control circuit 3
The current also increases. Therefore, the control circuit 3 continues to operate.
Thus, the inverter circuit 1 also continues to operate.

Therefore, the power supply from the AC power supply Vs is stopped.
Even after stopping, the high frequency voltage Vn of the second supply source_ThreeIs the lamp power
Pressure V_LaVoltage for a long time
(See FIG. 9), as a result, the operation of the control circuit 3,
Switching element Q of inverter circuit 1₁, Q_TwoOn
The off operation continues for a long time. This is shown in FIG.
Switching element Q_TwoCurrent I flowing through_DSQ2The waveform
As can be seen, the switching element Q_TwoBig for
That the stress is continuously applied for a long time
Means Note that, from the AC power supply Vs shown in FIG.
Current I after the supply of power is stopped_DSQ2Waveform is the DC power supply voltage
(Vc₆) Decreases and the discharge lamp La₁, La _TwoGoes out
Sometimes it is generated as a so-called advanced phase waveform.
Element Q ₁, Q_TwoSteep and high when are turned on at the same time
Peak current is stress.

That is, in the conventional device, it is necessary to minimize the time during which a large stress is applied to the switching elements Q ₁ and Q ₂ when the power supply from the AC power supply Vs is stopped. After the power supply from Vs is stopped, the current supplied to the control circuit 3 is quickly reduced, and the time until the reset circuit in the control circuit 3 stops the operation of the control circuit 3 by decreasing the power supply voltage V _CC quickly is set. Must be shorter. Here, the voltage (DC power supply voltage) Vc ₆ across the capacitor C ₆ rapidly drops after the power supply from the AC power supply is stopped (see FIG. 9). Therefore, the second supply source may be obtained from a high-frequency voltage generation source that changes according to the DC power supply voltage Vc ₆ .

(Conventional Example 2) FIG. 10 is a circuit diagram showing another conventional example. Parts common to the first conventional example are denoted by the same reference numerals. In this conventional example, the DC voltage Vc ₁ obtained by smoothing the pulsating output voltage of the diode bridge DB with the smoothing capacitor C ₁ is converted into a high-frequency rectangular wave voltage V ₀ by the inverter circuit 1, and is converted via the transformer T _1. The discharge lamp is lit by being supplied to the load circuit 2 having the discharge lamp. It should be noted that the inverter circuit 1 has a pair of switching elements Q
₁ and Q ₂ , and the control circuit 3 controls ON / OFF of the switching elements Q ₁ and Q ₂ .

[0018] As the source for supplying power to the control circuit 3, a first source for supplying a current I ₁ to the capacitor C ₄ from the high potential side of the smoothing capacitor C ₁ via the resistor R _1, trans resistor R ₂ from the primary winding n ₃ of the T _1, there is a second source for supplying a current I ₂ to the capacitor C ₄ via the diode D _1. During normal operation, the capacitor C
The voltage (power supply voltage) V _CC between both ends of ₄ is a Zener diode Z
It is maintained at a predetermined level by the D _1, the control circuit 3
And supplies the consumption current I ₃ of. Note that the reset circuit is provided in the control circuit 3 as in the conventional example 1, and the control circuit 3 is operated when Vk ≦ V _CC by comparing the reference voltage Vk with the power supply voltage V _CC . It has a function of stopping the operation of the control circuit 3 when Vk> V _CC .

Here, the transformer T which is the second supply source₁of
Primary winding n_ThreeVn generated at_ThreeLooking at
Voltage Vn_ThreeIs the square wave voltage V₀That is, the DC voltage Vc₁
And the main switch SW₁
Is turned off, the DC voltage Vc ₁Changes in response to
Become Therefore, the main switch SW₁After is turned off
Voltage Vn_ThreeIs the DC voltage Vc₁In response to a rapid voltage drop
Current I_TwoAlso decreases quickly, the power supply voltage V_CCEarly low
Vk> V_CCControl circuit 3 stops when
And the time required to do so is reduced. Thereby, in this conventional example,
Solves the problem of the conventional example 1 and solves the problem of the inverter circuit 1.
Switching element Q₁, Q_TwoLarge stress is applied to
Time can be shortened.

[0020]

However, the above conventional example 2
Has the following problems. FIG. 11 shows a case where the power supply from the AC power supply Vs starts at time t ₀ and then starts at time t ₄
In is a diagram showing the magnitude relation of current I ₁ ~I ₃ until after the stop, the time course of the magnitude relationship between the voltage across Vc ₂ and the reference voltage Vk of the capacitor C _2. After the power supply from the AC power source Vs at time t ₀ starts (turns on the main switch SW _1), a current I ₁ from the first source is supplied to the voltage across Vc ₁ of the capacitor C ₁ is increased Capacitor C
Voltage across Vc _{4 4} also rises. Vc ₄ = V at time t ₁
When the voltage rises to k, since the operation of the control circuit 3 is started by the reset circuit, the current consumption I ₃ of the control circuit ₃ also increases, but the switching elements Q ₁ and Q _{2 included in} the inverter circuit 1 also turn on and off. , The supply of the current I ₂ from the second supply source is started. At this point, the relationship of I ₁ + I ₂ ≧ I ₃ needs to be established.

[0021] On the other hand, a light load period to the load circuit 2 at time t ₁ ~t ₃ (time t ₁ ~t _2: preheating period, the time t ₂ ~
(t ₃ : starting period), and from time t ₃ , the lighting period of the discharge lamp starts. Here, a description will be given of a temporal change of the current consumption I ₃ in the control circuit 3 from the preheating period to the lighting period. Consumption current I ₃ is preheating, start-up, high in the order of lighting. This is because the frequency of the drive signal for turning on / off the switching elements Q ₁ and Q ₂ becomes lower as the transition from the preheating-starting-lighting is made. That when the frequency of the drive signal is high preheating has a larger consumed current I _3, when low lighting frequency is small consumption current I _3. However, the first
And the sum of the current amounts supplied from the second supply source (= I ₁ +
For I ₂ ), it is necessary to consider the preheating period in which the consumption current I ₃ is the highest, so that an excessive current is supplied to the consumption current I ₃ during lighting (FIG. 11).
reference).

Next, when the main switch SW ₁ is turned on at time t ₄ to stop the power supply, the voltage Vc ₁ across the capacitor C ₁ and the output voltage Vo of the inverter circuit 1 decrease, so that the transformer T ₁ The high-frequency voltage Vn ₃ generated in the primary winding n ₃ also decreases, and the supply current amount I ₁ + I ₂ from the first and second supply sources also starts to decrease. After it became I ₁ + I ₂ = I ₃ at time t ₅ is, I ₁ + I ₂ <voltage across Vc ₂ of the capacitor C ₂ to the I ₃ (= the power supply voltage V _CC) also starts to decrease.

And time t₆And V_CC<When it reaches Vk
The reset circuit in the control circuit 3 functions and the control circuit 3
The operation stops, and the switch included in the inverter circuit 1 is
Element Q₁, Q_TwoThe on / off operation of is also stopped. Also figure
11 to switching element Q ₁, Q_TwoGreat stress
Is applied at time t_Four~ T₆Period. Only
While the time t_Four~ T_FivePower supply during
Flow rate I₁+ I_TwoStarts to decrease and the current consumption I_ThreeIs equal to
Until the power supply voltage V_CCBegins to decline
It is time t_FiveAfter that. Therefore, this time t_Four~ T
_FiveIs the main switch SW₁Is turned off and the power
Pressure V_CCIs considered a time loss before it begins to decline
be able to.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce a period in which a large stress is applied to a switching element included in an inverter circuit when power supply from an AC power supply is stopped. It is an object of the present invention to provide a discharge lamp lighting device that can perform the operation.

[0025]

According to a first aspect of the present invention, a DC power source obtained by rectifying and smoothing an AC power source and one or more switching elements turned on / off at a high frequency are provided. An inverter circuit for converting a DC voltage supplied from the DC power supply into a high-frequency voltage, a load circuit having one or more discharge lamps and connected to an output side of the inverter circuit, and turning on the switching element. A discharge lamp lighting device including a control circuit that turns off and controls the operating frequency of the inverter circuit, and a power supply circuit that supplies power for operation to the control circuit, wherein a current is supplied from the DC power supply to the control circuit A first supply source that supplies a current that is generated based on a high-frequency voltage output from the inverter circuit and that quantitatively changes in accordance with a power supply voltage of the DC power supply to a control circuit; A power supply circuit having a second supply source, and a current for switching at least a supply current amount from the first and second supply sources under a light load so as to reduce a supply current amount when the discharge lamp is turned on. Characterized in that the current amount switching means reduces the supply current amount at the time of discharge lamp lighting from the supply current amount at the time of light load by the current amount switching means, and reduces the current consumption of the control circuit at the time of discharge lamp lighting. By supplying the minimum necessary current, the amount of current supplied from the power supply circuit after the power supply from the AC power supply stops and the time until the control circuit stops operating can be shortened. it can. as a result,
A period in which a large stress is applied to a switching element included in the inverter circuit when power supply from the AC power supply is stopped can be reduced.

According to a second aspect of the present invention, in the first aspect, the discharge lamp is preheated and started at the time of the light load. The invention of claim 3 is the invention of claim 1 or 2
In the invention, the second supply source is constituted by a vibration element included in the load circuit, and the circuit configuration can be simplified.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the second supply source supplies a current by a high-frequency voltage generated between both ends of a switching element provided in the inverter circuit. The circuit configuration can be simplified. According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the current amount switching means is configured by changing an impedance from the second supply source to the control circuit. With a simple circuit configuration, the amount of current supplied from the second supply source can be easily switched.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects of the present invention, the current amount switching means varies the amplitude of a high-frequency voltage generated in the second supply source. The amount of current supplied from the second supply source can be easily switched with a simple circuit configuration. According to a seventh aspect of the present invention, in the first or second or third aspect of the invention, the second supply source generates a current by a high frequency voltage generated in a resonance circuit connected in parallel with the load circuit on the output side of the inverter circuit. Wherein the resonance frequency of the resonance circuit is higher than the resonance frequency of the load circuit.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the control circuit operates the inverter circuit at a first operating frequency set near a resonance frequency of the resonance circuit to control the filament of the discharge lamp. While preheating
The discharge lamp is lit by operating the inverter circuit at a second operation frequency set near the resonance frequency of the load circuit, and the control circuit changes the operation frequency of the inverter circuit to the first operation frequency. To the second operating frequency, the supply current amount at the time of discharge lamp lighting is reduced from the supply current amount at the time of light load, and the necessary current consumption of the control circuit at the time of discharge lamp lighting is minimized. The current can be supplied, and the time from when the power supply from the AC power supply stops to when the amount of current supplied from the power supply circuit decreases and the control circuit stops operating can be shortened. When the power supply is stopped, the period during which a large stress is applied to the switching element included in the inverter circuit can be shortened. In addition, the circuit configuration can be simplified and the cost can be reduced.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION

 (Embodiment 1) FIG. 1 is a circuit diagram showing Embodiment 1 of the present invention.
It is. Between the AC input terminals of the diode bridge DB
Switch SW₁Connect the commercial AC power supply Vs through
Full-wave rectification and DC of diode bridge DB
Smoothing capacitor C connected between output terminals₁DC with smoothing
Voltage Vc₁Have gained. DC of diode bridge DB
Smoothing capacitor C between output terminals₁And a pair of switches in parallel
Ching element Q₁, Q_TwoAre connected in series.
A so-called half-bridge type inverter circuit 1 is configured.
You. These switching elements Q₁, Q_TwoAre each
Iod D₁, D _TwoAre connected in anti-parallel
Although it is composed of a transistor, it is
Consisting of field effect transistors with raw diodes
May be.

A series circuit of a DC component cutting capacitor C ₃ and a primary winding n ₁ of a leakage transformer (hereinafter simply referred to as a “transformer”) T ₁ is connected in parallel to the switching element Q ₂ on the low potential side. It is connected. The secondary winding n ₂ of the transformer T ₁ and the capacitor C ₂ is the discharge lamp La is connected in parallel, the transformer T _1, the load circuit 2 is constituted by the capacitor C ₂ and the discharge lamp La.

Switching element of inverter circuit 1
Q₁, Q_TwoIs alternately turned on at high frequency by the control circuit 3.
Turned off. Thereby, between the output terminals of the inverter circuit 1
High frequency rectangular wave voltage V₀And supplies it to the load circuit 2.
Thus, the discharge lamp La is turned on at a high frequency. On the other hand,
Capacitor C₁Between both ends of the resistor R₁And the Zener Dio
Lead ZD ₁And capacitor C_FourSeries circuit with parallel circuit
Is connected and the resistor R₁And capacitor C_FourAt the connection point with
The control circuit 3 (actually a power supply terminal) is connected. Again
Lance T₁Secondary winding n_ThreeOne terminal of
The other terminal is connected to the current amount switching circuit 5 and the die.
Aether D_ThreeThrough the resistor R₁And capacitor C_FourConnection with
Connected to a point. Thus, the resistance R₁, Zener Dio
Lead ZD₁, Capacitor C_Four, Diode D_ThreeAnd
Operation power is supplied to the control circuit 3 by the flow rate switching circuit 5
The power supply circuit 4 is configured. Here, the current amount switching circuit 5
Is the resistance R_TwoAnd the resistance R_ThreeAnd switch SW_TwoSeries times
And a switching circuit by the control circuit 3.
Switch_TwoIs controlled on / off. However, switch SW
_TwoMay be separately provided. What
The reset circuit is provided in the control circuit 3 as in the conventional examples 1 and 2.
Path (not shown), and is provided by the comparator CP.
The reference voltage Vk and the power supply voltage V_CCAnd Vk ≦
V_CCControl circuit 3 is operated when Vk> V_CCWhen
Has a function of stopping the operation of the control circuit 3.

The inverter circuit 1 of the present embodiment is conventionally well-known.
The half-bridge type inverter circuit of
A pair of switching elements Q₁, Q_TwoAlternately
DC voltage Vc by turning on / off at high frequency₁The high frequency
The voltage is converted to a voltage and supplied to the load circuit 2 to make the discharge lamp La
Waves are lit. Next, operation power is supplied to the control circuit 3.
The operation of the power supply circuit 4 will be described. For power supply circuit 4
Power supply has two paths, one of which is smooth
Capacitor C₁From the high potential side of the resistor R₁Through the current I
₁Is a first supply source. And the second one is Tran
S₁Secondary winding n_ThreeFrom the current amount switching circuit 5
Do D _ThreeAnd the current I through_TwoA second source that supplies
You. Here, the secondary winding n_ThreeHigh-frequency voltage Vn generated at_Three
Is the smoothing capacitor C₁(DC voltage) Vc₁To
A voltage that changes correspondingly.

FIG. 2 shows the currents I _{1 to} I ₃ from when the power supply from the commercial AC power supply Vs is started at time t ₀ to when it is stopped at time t ₄ (I ₃ is the current consumption in the control circuit 3).
FIG. 7 is a diagram showing a temporal change in the magnitude relationship between the voltage Vc ₄ across the capacitor C ₄ and the magnitude relationship between the reference voltage Vk and the voltage Vc ₄ . Time t
₀ after the power supply from the AC power source Vs starts (turns on the main switch SW _1), the electric current I ₁ from the first source is supplied to the voltage across Vc ₁ of the smoothing capacitor C ₁ is increased capacitor The voltage Vc ₄ across C ₄ also increases. When the voltage rises to Vc ₄ = Vk at time t ₁ , the operation of the control circuit 3 is started by the reset circuit, and the current consumption I ₃ of the control circuit ₃ also increases.
, The switching elements Q ₁ and Q _{2 included} therein also start the on / off operation, so that the supply of the current I ₂ from the second supply source is started. At this point, the relationship of I ₁ + I ₂ ≧ I ₃ needs to be established.

By the way, as described in the conventional example 2, the current consumption I in the control circuit 3 from the preheating period to the lighting period.
₃ is supplied from the first and second supply sources in the conventional example 2 in spite of the fact that the frequency of the drive signal of the switching elements Q ₁ and Q ₂ is large at the time of high preheating and small at the time of low frequency lighting. It has been performed excessive current supply for the current amount of the sum (= I ₁ + I ₂₎ current consumption I ₃ at the time of lighting in consideration of the highest becomes preheating period current consumption I ₃ is.

In the present embodiment, on the other hand, at time t ₁ to time t ₁
t light load period up to ₃ (time t ₁ ~t _2: preheating period, the time t ₂ ~t _3: starting period) current amount switching circuit turns on the switch SW ₂ of the current amount switching circuit 5 by the control circuit 3 5 with increasing current I ₂ by reducing the combined resistance of, reduces the current I ₂ by increasing the combined resistance of the current amount switching circuit 5 turns off the switch SW ₂ at the time of time t ₃ after lighting (See FIG. 2). That is,
Turns on the switch SW ₂ is in a light load period necessary and sufficient current I ₂ to the preheating and starting to allow supplied, the current I ₂ at the time of lighting to the extent required sufficient to maintain the lighting off the switch SW ₂ By reducing the supply amount, the time t
_The main switch SW ₁ is turned off at 4 and the commercial AC power supply V
s until the operation of the control circuit 3 is stopped by the reset circuit (time t _4).
To t ₆ ) can be reduced as compared with Conventional Example 2 (see FIGS. 2 and 11). However, I ₁ + I ₂ ≧ I
The resistance values of the resistors R ₂ and R ₃ are set so that the relationship of ₃ is satisfied.

In the present embodiment, the period from when the power supply by the commercial AC power supply Vs is stopped by providing the current amount switching circuit 5 to when the operation of the control circuit 3 is stopped by the reset circuit is set to the conventional example. As a result, it is possible to shorten the period during which a current that causes a large stress on the switching elements Q ₁ and Q _{2 of} the inverter circuit 1 flows.

(Embodiment 2) FIG. 3 shows Embodiment 2 of the present invention.
FIG. The basic configuration of the present embodiment is almost the same as that of the first embodiment, and the common portions are denoted by the same reference numerals and description thereof is omitted. A pair of switching elements Q ₁ and Q ₂ constituting the half-bridge type inverter circuit 1 are constituted by MOSFETs having a parasitic diode, and are connected to the low-potential side switching element Q ₂ via a DC component cutting capacitor C _3. 1 of T ₂
Winding n ₁ and the load circuit 2 'are connected in parallel. The load circuit 2 'are those formed by connecting to the filament of the discharge lamp La and capacitor C ₂ for preheating current application to form a choke coil L ₁ and the resonant circuit choke coil L _1. As in the first embodiment, the control circuit 3 alternately turns on and off the switching elements Q ₁ and Q ₂ at a high frequency, thereby converting the DC voltage Vc ₁ into a high-frequency rectangular wave voltage Vo. To discharge the discharge lamp La.

On the other hand, as in the first embodiment,
C₁Between both ends of the resistor R₁And Zener diode ZD
₁And capacitor C_FourThe parallel circuit and the series circuit are connected.
And the resistance R₁And capacitor C_FourControl circuit 3 at the connection point with
Is connected. Transformer T₁Secondary winding n_TwoOne
One terminal is connected to ground, and the other terminal is
Conversion circuit 5 'and diode D_ThreeThrough the resistor R₁And con
Densa C_FourIs connected to the connection point. Thus, the resistance R
₁, Zener diode ZD₁, Capacitor C _Four, Die
Aether D_ThreeThe control circuit is controlled by the current amount switching circuit 5 '.
A power supply circuit 4 ′ for supplying operating power to the path 3 is configured.
Here, the current amount switching circuit 5 'includes a resistor R_Two, R_ThreeSeries times
Road and resistance R_ThreeSW connected in parallel to_TwoComposed of
The switch SW is controlled by the control circuit 3._TwoIs on / off
Controlled. However, switch SW _TwoOn / off control
Means may be separately provided.

Next, with reference to FIG.
The operation of the source circuit 4 'will be described. First, time t₀Exchange with
Power supply from the power supply Vs starts (main switch SW
₁Is turned on), and then the smoothing capacitor C₁Voltage Vc
₁Rises in the first supply (smoothing capacitor C₁
From the high potential side of the resistor R₁Through the current I₁Supply)
From the current I₁Is supplied to the capacitor C_FourVoltage V
c_FourAlso rises. Time t₁At Vc_Four= Rise to Vk
Then, the operation of the control circuit 3 is started by the reset circuit.
Therefore, the consumption current I of the control circuit 3_ThreeIncrease
Switching element Q included in barter circuit 1₁, Q_TwoAlso
Since the on / off operation is started, the second power source (transformer
T₁Secondary winding n_TwoFrom the current amount switching circuit 5 '
Do D_ThreeAnd the current I through_TwoCurrent I)_Two
Is started to be supplied. At this point, I₁+ I_Two≧ I_Three
Must be established. Here, time t₁~ T_Three
In the light load period up to the current amount switching circuit by the control circuit 3
5 'switch SW_TwoTo the current amount switching circuit 5 '
Resistance R_ThreeSwitch SW_TwoLet through the
Current I_TwoAt time t_ThreeOr later
When switch is on, switch SW_TwoTurn off the current switching circuit
By increasing the combined resistance of the 5 ', the current I_TwoDecrease
(See FIG. 2). That is, during the light load period, the switch
Switch_TwoIs turned on to supply sufficient current I for preheating and starting.
_TwoCan be supplied, and when lit, switch SW_TwoTurn off
Current I to the extent necessary to maintain lighting_TwoSupply of
By reducing the amount, the time t_FourAnd the main switch S
W ₁Is turned off and the power supply from the commercial AC power supply Vs stops.
After the stop, the operation of the control circuit 3 is performed by the reset circuit.
Period until suspension (time t_Four~ T₆) To Conventional Example 2
(See FIGS. 2 and 11)
See). However, I₁+ I_Two≧ I_ThreeThe relationship is satisfied
So that the resistance R_Two, R_ThreeIs set.

Thus, in the present embodiment, similarly to the first embodiment, the operation of the control circuit 3 is stopped by the reset circuit after the power supply from the commercial AC power supply Vs is stopped by providing the current amount switching circuit 5 '. As a result, it is possible to shorten the period in which a current that causes a large stress on the switching elements Q ₁ and Q _{2 included in} the inverter circuit 1 flows.

(Embodiment 3) FIG. 4 shows Embodiment 3 of the present invention.
Since the basic configuration is the same as that of the second embodiment, the common parts are denoted by the same reference numerals, and the description thereof will be omitted. The power supply circuit 4 ″ which is a feature of the present embodiment will be described.
Only the configuration will be described. In this embodiment, a resistor R ₁ and a series circuit of a parallel circuit of a Zener diode ZD ₁ and a capacitor C ₄ are connected between both ends of a smoothing capacitor C ₁ , similarly to the first and second embodiments, and the resistor R ₁
Control circuit 3 and the connection point between the capacitor C ₄ is is connected. The intermediate tap is provided to the secondary winding n ₂ of the transformer T _2, together with one terminal of the secondary winding n ₂ is connected to ground, the switch SW ₂ and the other terminal, the resistor R _2, a diode Resistor R ₁ and capacitor C via D ₃
Yes connected to the connection point of the _4, is connected to a connection point of the switch SW ₂ and a resistor R ₂ further said intermediate tap via a switch SW _3. That is, the secondary winding n ₂ and two switches SW ₂ of the transformer T ₂ are in this embodiment, S
W ₃ "is configuration, the resistance R _1, the Zener diode ZD _1, capacitor C _4, the diode D ₃ and the current amount switching circuit 5" current amount switching circuit 5 by the supply operating power to the control circuit 3 a power supply circuit 4 The switches SW ₂ , SW of the current amount switching circuit 5 ″
₃ is turned on / off by the control circuit 3. However,
A means for turning on / off the switches SW ₂ and SW ₃ may be separately provided.

Next, the operation of the power supply circuit 4 ″ in this embodiment will be described with reference to FIG. 2. First, at time t ₀ , power supply from the AC power supply Vs starts (the main switch SW).
_{After 1} was turned on), the voltage Vc across the smoothing capacitor C _1
1 rises to the first source (smoothing capacitor C ₁
Supplying a current I ₁ from the high potential side through the resistor R ₁₎
Current I ₁ is supplied from the voltage V across the capacitor C ₄
c ₄ also rises. When the voltage rises to Vc ₄ = Vk at time t ₁ , the operation of the control circuit 3 is started by the reset circuit, so that the current consumption I ₃ of the control circuit ₃ also increases, but the switching elements Q ₁ , Q ₂ is also the current I ₂ from the second source so starting the on-off operation (for supplying a current I ₂ from the secondary winding n ₂ of the transformer T ₁₎ is initiated supplied. At this point, I ₁ + I ₂
The relationship of ≧ I ₃ needs to be satisfied.

Here, during the light load period from time t _{1 to} time t ₃ , the control circuit 3 controls the switch S of the current amount switching circuit 5 ″.
W ₂ ON, high secondary voltage of the transformer T ₂ to turn off the SW ₃ with increasing current I ₂ by (the amplitude increases), and the time t ₃ after the turning off the switch SW ₂ at the time of lighting, SW ₃ oN to lower the secondary voltage of the transformer T ₂ in which (a small amplitude) and decreased the current I ₂ (FIG. 2
reference). That is, light load on the switch SW ₂ is in the period, and turns off the SW ₃ the necessary and sufficient current I ₂ to the preheating and starting to allow supplying, turning off the switch SW ₂ at the time of lighting, the lighting is turned on and SW ₃ By reducing the supply amount of the current I _{2 to} an extent necessary and sufficient to maintain the time t ₄
In the main switch SW ₁ is turned off the commercial AC power source Vs
Period by since the power supply is stopped until the operation of the control circuit 3 is stopped by the reset circuit (time t ₄ ~
t ₆ ) can be reduced as compared with Conventional Example 2 (see FIGS. 2 and 11). However, the resistance values of the resistors R ₂ and R ₃ are set such that the relationship of I ₁ + I ₂ ≧ I ₃ is always satisfied.

In this embodiment, similarly to the first and second embodiments, the current amount switching circuit 5 ″ is provided, and after the power supply from the commercial AC power supply Vs is stopped, the control circuit 3 is reset by the reset circuit. The period until the operation is stopped can be shortened as compared with the conventional example 2, and as a result, the period during which a current that causes a large stress on the switching elements Q ₁ and Q _{2 included in} the inverter circuit 1 can be reduced. Becomes

(Embodiment 4) FIG. 5 shows Embodiment 4 of the present invention.
Since the basic configuration is the same as that of the third embodiment, common parts are denoted by the same reference numerals, and description thereof will be omitted. The configuration of the power supply circuit 6 which is a feature of the present embodiment will be described. Will be described only. In the present embodiment, a resistor R _{1 is connected} between both ends of the smoothing capacitor C ₁ as in the _first to third embodiments.
If, zener series circuit of a parallel circuit of diodes ZD ₁ and a capacitor C ₄ is connected, the resistance R ₁ and a control circuit 3 to a connection point between the capacitor C ₄ is connected. The connection point of the switching elements Q ₁ and Q ₂ (the drain terminal of the switching element Q ₂ on the low potential side) constituting the inverter circuit 1 is connected to the resistor R ₁ and the capacitor C ₄ via the diode D _{3 and the} current amount switching circuit 7. Is connected to the connection point.

The current amount switching circuit 7 includes capacitors C ₅ and C ₆
Configured to switch SW ₂ to the capacitor C ₆ with the series circuit and the resistor R ₂ connected in parallel with parallel connection of.
The power supply circuit 6 that supplies operating power to the control circuit 3 is configured by the resistor R ₁ , the Zener diode ZD ₁ , the capacitor C ₄ , the diode D ₃ , and the current amount switching circuit 7. The switch SW ₂ of the current amount switching circuit 7 is on / off controlled by the control circuit 3. However, it may be separately provided with means for on-off control of the switch SW _2.

Next, with reference to FIG.
The operation of the source circuit 6 will be described. First, time t₀Interact with
Power supply from power supply Vs starts (main switch SW₁
Is turned on), and then the smoothing capacitor C₁Voltage Vc₁
Rises in the first supply (smoothing capacitor C₁of
Resistance R from high potential side₁Through the current I₁Supply) or
Current I₁Is supplied to the capacitor C_FourVoltage Vc
_FourAlso rises. Time t ₁At Vc_Four= Rise to Vk
Then, the operation of the control circuit 3 is started by the reset circuit.
Therefore, the consumption current I of the control circuit 3_ThreeIncrease
Switching element Q included in barter circuit 1₁, Q_TwoAlso
Current from the second source to initiate on / off operation
I_TwoIs started to be supplied. At this point, I₁+ I_Two≧
I_ThreeMust be established. Here, the present embodiment
Is a source that constitutes the inverter circuit 1.
Switching element Q_TwoVoltage V_DSQ2Obtained from
Voltage V_DSQ2Is the main switch SW₁After turning off
Is a capacitor C₁Voltage Vc₁Responded to changes in
It shows the characteristics.

In this embodiment, at time t₁~ T_ThreeUp to light
During the load period, the control circuit 3 switches the current amount switching circuit 6.
Switch_TwoTurn on the capacitor C₆Switch SW_Two
The current I_TwoWith increasing
At time t_ThreeWhen the light is turned on, switch SW_TwoTurn off
To increase the combined impedance of the current amount switching circuit 6
The current I_Two(See FIG. 2). Sand
In the light load period, the switch SW_TwoTurn on and preheat
Sufficient current I for starting_TwoCan be supplied and when lit
Is a switch SW_TwoIt is necessary and sufficient to turn off the light
The current I_TwoBy reducing the supply of
Time t_FourAnd the main switch SW₁Is turned off and the commercial AC power
After the power supply from the source Vs is stopped,
Therefore, the period (time) until the operation of the control circuit 3 is stopped.
t_Four~ T₆) Can be shortened compared to the conventional example 2.
(See FIGS. 2 and 11). However, I₁+ I_Two≧
I _ThreeSo that the resistance R_TwoResistance value and
Capacitor C_Five, C₆Is set.

In this embodiment, similarly to the first to third embodiments, the operation of the control circuit 3 is stopped by the reset circuit after the power supply from the commercial AC power supply Vs is stopped by providing the current amount switching circuit 7. The time required for the switching operation can be shortened as compared with the conventional example 2. As a result, it is possible to shorten the period during which a current that causes a large stress on the switching elements Q ₁ and Q _{2 included in} the inverter circuit 1 flows.

(Embodiment 5) FIG. 6 shows Embodiment 5 of the present invention.
FIG. As shown in FIG. 6, the basic configuration of the present embodiment is the same as that of the conventional example 1. Therefore, the common portions are denoted by the same reference numerals, and description thereof will be omitted. Only the configuration of the circuit 8 will be described.

The features of the power supply circuit 8 in this embodiment are as follows.
Preheating transformer T constituting preheating resonance circuit 11_FourSet in
Secondary winding n_ThreeIs connected to ground and the other end is
Resistance R_TwoAnd diode D_FiveThrough the resistor R₁And conde
Sensor C₁₄And the current I_TwoSupply
That is, it is a second supply source. FIG. 7 illustrates the present embodiment.
Characteristics of the lighting resonance circuit 10 and the preheating resonance circuit 11
The horizontal axis represents the operating frequency of the inverter circuit 1.
f, the vertical axis is the voltage, and the curve a is the discharge lamp La₁, La
_TwoTransformer T before lights up_ThreeSecondary voltage Vn _Two, Song
Wire transformer T for preheating_FourPrimary side voltage Vn_Four, Curve c
Is the discharge lamp La₁, La_TwoTransformer T after lighting_ThreeSecondary side of
Voltage Vn_TwoIt is. Also f₁Are common to the lighting resonance circuit 10.
Vibration frequency, f_TwoIs the resonance frequency of the preheating resonance circuit 11.
(Note that f₁<F_Two).

Incidentally, the inverter circuit 1 in the present embodiment has a first operating frequency fa and a second operating frequency f.
b, and these operating frequencies f
a and fb are switched. First operating frequency fa is set in the vicinity of the resonance frequency f ₂ of the preheating resonant circuit 11, the inverter circuit 1 by the control circuit 3 in the first operating frequency fa
Is operated, a preheating current is supplied to the filaments of the discharge lamps La ₁ and La ₂ via the preheating resonance circuit 11.

Next, after sufficient preheating is performed, the control circuit 3
Switch from the first operating frequency fa to the second operating frequency fb
Change. The second operating frequency fb is equal to the operating frequency of the lighting resonance circuit 10.
Resonance frequency f₁Is set near the discharge lamp La₁,
La_TwoHigh voltage necessary for starting the inverter
It is supplied via the lighting resonance circuit 10. And discharge
Light La₁, La_TwoLights up, the lighting resonance circuit 10
Because the vibration conditions change, the resonance characteristics change from curve A to curve C.
Transition. At this time, a preliminary operation at the second operating frequency fb is performed.
The resonance voltage of the thermal resonance circuit 11 (the preheating transformer T_Four2
Secondary voltage) Vn _FourIs much lower than during preheating.
(Point B on the curve b).

On the other hand, the voltage Vn ₃ generated in the secondary winding n ₃ of the preheating transformer T ₄ constituting the power supply circuit 8 also has the same characteristics as the resonance voltage Vn _4. the amount of current I ₂ supplied to the 3 most at light load (during preheating and starting), will be reduced at the time of lighting. As a result, similarly to the _first to fourth embodiments, the period from when the main switch SW1 is turned off and the power supply from the commercial AC power supply Vs is stopped to when the operation of the control circuit 3 is stopped by the reset circuit is the second conventional example. Can be shortened as compared to Moreover, in the present embodiment, since making up the amount of current switching means by the secondary winding n ₃ of the preheating transformer T _4, the amount of current and the like resistors and switches SW ₂ as in the embodiment 1-4 There is no need to provide the switching circuits 4..., And there is an advantage that the cost can be greatly reduced.

Thus, in the present embodiment, similarly to the first to fourth embodiments, the period from when the power supply by the commercial AC power supply Vs is stopped to when the operation of the control circuit 3 is stopped by the reset circuit is the second conventional example. , And as a result,
Switching elements Q ₁ and Q included in the inverter circuit 1
_This makes it possible to shorten the period during which a current that causes a large stress to flow in the _second embodiment, and is more advantageous in cost than the first to fourth embodiments.

[0057]

According to the first aspect of the present invention, there is provided a DC power supply comprising a DC power supply obtained by rectifying and smoothing an AC power supply, and one or more switching elements which are turned on / off at a high frequency. Circuit, a load circuit having one or a plurality of discharge lamps connected to the output side of the inverter circuit, and controlling the operating frequency of the inverter circuit by turning on / off the switching element. A discharge lamp lighting device, comprising: a control circuit for performing the operation, and a power supply circuit for supplying an operation power supply to the control circuit, wherein a first supply source for supplying a current from the DC power supply to the control circuit;
A power supply circuit including a second supply source that supplies a control circuit with a current generated based on a high-frequency voltage output from the inverter circuit and that quantitatively changes according to a power supply voltage of the DC power supply; Current amount switching means for switching the amount of supply current from the first and second supply sources during load to reduce the amount of supply current when the discharge lamp is turned on. By reducing the amount of current supplied when the discharge lamp is lit from the amount of current supplied when the load is on, the minimum necessary current can be supplied to the control circuit when the discharge lamp is lit. After the power supply is stopped, the amount of current supplied from the power supply circuit decreases and the time required for the control circuit to stop operating can be shortened. As a result, the power supply from the AC power supply can be reduced. Great stress upon feeding stop switching element inverter circuit comprises that there is an effect that it is possible to shorten the time to be applied. Since the load circuit includes the vibrating element, the circuit configuration can be simplified.

According to a third aspect of the present invention, the second supply source comprises:
Since the load circuit includes the vibrating element, the circuit configuration can be simplified. According to the fourth aspect of the present invention, the second supply source supplies an electric current by using a high-frequency voltage generated between both ends of the switching element included in the inverter circuit, so that the circuit configuration can be simplified.

According to a fifth aspect of the present invention, the current amount switching means changes the impedance from the second supply source to the control circuit, so that the supply from the second supply source can be performed with a simple circuit configuration. There is an effect that the amount of current can be easily switched. According to a sixth aspect of the present invention, since the current amount switching means varies the amplitude of the high frequency voltage generated in the second supply source, the supply current amount from the second supply source can be easily reduced with a simple circuit configuration. There is an effect that can be switched to.

The invention according to claim 8 is characterized in that the control circuit operates the inverter circuit at a first operating frequency set near the resonance frequency of the resonance circuit to preheat the filament of the discharge lamp, and to load the filament of the discharge lamp. Since the discharge lamp is lit by operating the inverter circuit at a second operating frequency set near the resonance frequency of the circuit, the control circuit changes the operating frequency of the inverter circuit from the first operating frequency to the second operating frequency. By lowering the frequency, the supply current at the time of discharge lamp lighting is reduced from the supply current at light load, making it possible to supply the minimum necessary current for the control circuit current consumption at discharge lamp lighting. ,
After the power supply from the AC power supply stops, the amount of current supplied from the power supply circuit decreases and the time until the control circuit stops operating can be shortened. This has the effect of shortening the period during which a large stress is applied to the switching elements included in the circuit, and simplifying the circuit configuration and reducing the cost.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is an explanatory diagram for explaining the operation of the above.

FIG. 3 is a circuit diagram showing a second embodiment.

FIG. 4 is a circuit diagram showing a third embodiment.

FIG. 5 is a circuit diagram showing a fourth embodiment.

FIG. 6 is a circuit diagram showing a fifth embodiment.

FIG. 7 is an explanatory diagram for explaining the above operation.

FIG. 8 is a circuit diagram showing a first conventional example.

FIG. 9 is a waveform chart for explaining the above operation.

FIG. 10 is a circuit diagram showing a second conventional example.

FIG. 11 is an explanatory diagram for explaining the above operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Inverter circuit 2 Load circuit 3 Control circuit 4 Power supply circuit 5 Current amount switching circuit Vs AC power supply SW ₁ Main switch SW ₂ Switch La Discharge lamp T ₁ Transformer n ₃ Secondary winding Q ₁ , Q ₂ Switching element C ₁ Smoothing capacitor R ₁ to R ₃ resistor C ₄ capacitors ZD ₁ Zener diode D ₃ diode

Claims (8)

[Claims] An inverter for converting a DC voltage supplied from the DC power supply into a high-frequency voltage, comprising a DC power supply obtained by rectifying and smoothing an AC power supply, and one or more switching elements that are turned on and off at a high frequency. A circuit, a load circuit having one or a plurality of discharge lamps and connected to an output side of the inverter circuit, a control circuit for turning on / off the switching element to control an operating frequency of the inverter circuit, A discharge lamp lighting device comprising: a power supply circuit for supplying an operation power supply to a circuit; a first supply source for supplying a current from the DC power supply to the control circuit, based on a high-frequency voltage output from the inverter circuit. A power supply circuit comprising a second supply source that supplies a control circuit with a current that is generated and varies quantitatively according to a power supply voltage of the DC power supply;
Current supply switching means for switching at least the supply current from the first and second supply sources at light load to reduce the supply current at discharge lamp lighting. Lighting device. 2. The discharge lamp lighting device according to claim 1, wherein the preheating and starting of the discharge lamp are performed at the time of the light load. 3. The discharge lamp lighting device according to claim 1, wherein the second supply source includes a vibration element included in the load circuit. 4. The discharge lamp lighting device according to claim 1, wherein the second supply source supplies a current by using a high-frequency voltage generated between both ends of a switching element included in the inverter circuit. 5. The discharge lamp lighting device according to claim 1, wherein said current amount switching means changes an impedance from said second supply source to said control circuit. . 6. The discharge lamp lighting device according to claim 1, wherein said current amount switching means varies the amplitude of a high-frequency voltage generated in said second supply source. 7. The second supply source supplies a current to an output side of the inverter circuit by a high-frequency voltage generated in a resonance circuit connected in parallel with the load circuit,
4. The discharge lamp lighting device according to claim 1, wherein a resonance frequency of the resonance circuit is higher than a resonance frequency of the load circuit. 8. The control circuit operates the inverter circuit at a first operating frequency set near a resonance frequency of the resonance circuit to preheat a filament of the discharge lamp, and controls a frequency near a resonance frequency of the load circuit. 8. The discharge lamp lighting device according to claim 7, wherein the discharge lamp is lit by operating the inverter circuit at a second operating frequency set in (1).