JPH0562784A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To improve the starting performance of a discharge lamp such as HID and reduce the stress of switching elements concurrently. CONSTITUTION:A serial circuit of switching elements S1, S2 and a serial circuit of capacitors C3, C4 are connected to both ends of a DC power source E respectively. A lighting circuit constituted of the first inductor L1, the secondary winding n2 of a pulse transformer PT1, a discharge lamp La, and a bypass capacitor C1 and a pulse generating means constituted of the second inductor L2, a pulse generating capacitor C2, the primary winding n1 of the pulse transformer PT1, and a pulse generating switch element S5 are connected between connection points (c), (d) of both serial circuits. Since the inductor L2 acts as part of the circuit elements of a step-down chopper, the inductor L2 can be used as the charging means of the pulse generating capacitor C2 without providing an energy releasing circuit in particular.

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 for lighting a discharge lamp at a high frequency.

[0002]

2. Description of the Related Art Conventionally, a discharge lamp lighting device that receives a DC voltage from a DC power source, converts it into a high frequency voltage, and lights a discharge lamp is often used. Further, when it is necessary to apply a high voltage at the time of starting the discharge lamp, a pulse generating means is generally often used.

FIG. 4 shows a conventional example of a discharge lamp lighting device which requires such a high pulse voltage.
The configuration is such that first and second switching elements S1 and S2 are connected in series at both ends of the DC power source E, and further, third and fourth switching elements S3 and S3 are connected at both ends of the DC power source E.
S4 is connected and the first and second switching elements S1,
The connection point of S2 and the third and fourth switching elements S3, S
The series circuit of the secondary winding n2 of the pulse transformer PT10 and the discharge lamp La is connected to the connection point of No. 4 via the first inductor L1, and the secondary winding n2 of the pulse transformer PT10 is connected.
In a discharge lamp lighting device in which a bypass capacitor C1 is connected in parallel with a series circuit of the discharge lamp La and the discharge lamp La, as a means for generating a pulse voltage in the secondary winding n2 of the pulse transformer PT10, A series circuit of a pulse generating capacitor C21 and a resistor R10 is connected in parallel with the series circuit of the secondary winding n2 of the pulse transformer PT10 and the discharge lamp La, and the primary circuit of the pulse transformer PT10 is connected to both ends of the pulse generating capacitor C21. The winding n1 and the pulse generating switch element S51 are connected in series.
In addition, diodes D1 to D4 are connected in antiparallel to each switching element.

The operation state will be briefly described below. First, a control circuit (not shown) receives a DC voltage E and starts operating. Drive signals are supplied from the control circuit to the switching elements S1 to S4.
The switching elements S1 and S4 and the second and third switching elements S2 and S3 alternately start turning on and off. An alternating voltage is generated between the terminals cd by the ON / OFF operation of each of the switching elements S1 to S4, and the pulse generating capacitor C21 is connected to the resistor R during the half cycle of the alternating voltage.
It is gradually charged via 10. When the charging voltage is sufficiently charged, the pulse generating switch element S51 (for example, a triac) receives a signal from a driving circuit (not shown) and shifts to an ON state.

When the pulse generating switch element S51 shifts to the ON state, the electric charge accumulated in the pulse generating capacitor C21 is rapidly released, and a transient current flows through the primary winding n1 of the pulse transformer PT10, and the secondary winding A high voltage pulse voltage is generated across n2. This high-voltage pulse voltage is applied to both ends of the discharge lamp La via the bypass capacitor C1, and the discharge lamp La starts and shifts to a lighting state.

By the way, in such a conventional example,
There is a problem that the charging voltage of the pulse generating capacitor C21 changes and the pulse voltage changes depending on whether the voltage across the discharge lamp La is high or low. Therefore, when the discharge lamp La starts discharge breakdown and shifts from glow discharge to arc discharge,
In particular, in the case of a high-pressure discharge lamp La such as a metal halide lamp, the pulse energy of the pulse voltage also decreases as the voltage across the discharge lamp La decreases, and some arcs cannot smoothly transition to arc discharge.

Therefore, in order to solve the above problem, FIG.
The inventors have also examined a device in which a resistor R11 and a pulse generating capacitor C21 are connected in series between the terminals cd as shown in FIG. Capacitor C for generating pulse from voltage
There is a problem that the loss of the resistor R11 that charges 21 is increased and the circuit efficiency is reduced.

For this reason, the inventors have considered a charging means as shown in FIG. The one shown in FIG. 6 (a) uses the inductor L, but in this one, a closed circuit for discharging the energy accumulated in the inductor L when the switch S is off is required, and the resistor R is newly added. Will be needed. The one shown in FIG. 6B is the same as that shown in FIG. 5 described above, and the loss of the resistance R becomes a problem. Figure 6
Although what is shown in (c) is due to the partial pressure of the capacitors C0 and C, the capacitor C is placed between cd and d shown in FIG.
When 0 and C are connected, a low impedance circuit for high frequency current is formed, and each switching element S1 to
There is a problem that the current burden of S4 increases.

[0009]

In the above-mentioned conventional example, when the circuit efficiency is improved, it is difficult to smoothly shift the discharge lamp from the glow discharge to the arc discharge and the starting performance is deteriorated. On the other hand, When the starting performance is improved, there is a problem in that loss due to resistance increases, a new circuit for discharging energy of the inductor is newly formed, and stress to each switching element increases.

The present invention is intended to solve such a problem, and an object of the present invention is to prevent discharge of the circuit efficiency from being lowered and to maintain good starting performance of the discharge lamp. An object is to provide an electric lighting device.

[0011]

Means for Solving the Problems First and second switching elements connected in series to both ends of a DC power source, and first and second capacitors (switching elements may be connected in series to both ends of the DC power source). .), The secondary winding of the pulse transformer and the discharge lamp connected via the first inductor between the connection point of the first and second switching elements and the connection point of the first and second capacitors. And a bypass capacitor connected in parallel with the series circuit of the secondary winding of the pulse transformer and the discharge lamp, and the connection point of the first and second switching elements and the first and second Of the pulse generating capacitor connected via the second inductor to the connection point of the capacitor, and the primary winding of the pulse transformer and the pulse generating switch element connected to both ends of the pulse generating capacitor. It is characterized in that formed by and a column circuit.

[0012]

According to the present invention, the series circuit of the inductor and the pulse generating capacitor is formed in parallel with the series circuit of the first inductor, the secondary winding of the pulse transformer and the discharge lamp, and the pulse generation is performed. Since the series circuit of the primary winding of the pulse transformer and the switch element for pulse generation is provided at both ends of the capacitor for use in the discharge lamp, it is possible to prevent deterioration of circuit efficiency and maintain the starting performance of the discharge lamp.

[0013]

FIG. 1 shows a first embodiment of the present invention.
The configuration different from that of the conventional example shown in FIG.
1 is replaced with a second inductor L2, a series circuit of a die-auto D3 anti-parallel connected to the third switching element S3 and a diode D4 anti-parallel connected to the fourth switching element S4 is connected to a capacitor C3. Capacitor C
4 is replaced with a series circuit. It should be noted that the same components are denoted by the same reference numerals and redundant description is omitted.

By replacing the second inductor L2 with the second inductor L2 as described above, the energy stored in the second inductor L2 is changed to the second inductor L2 while each switching element is in the OFF state. Since it is discharged to the closed loop f from L2 to the capacitor C3 → DC power source E → diode D2 → second inductor L2, an excessive voltage is not generated across the second inductor L2 (first switching element). In the circuit in which S1 is turned on / off and the second switching element S2 is maintained in the off state, and then the rectangular wave voltage is generated by the reverse operation, the operation of the step-down chopper is alternately repeated. ).

FIG. 2 shows a second embodiment of the present invention. The configuration different from the first embodiment is that the capacitor C
3. The point is that a switching element or the like is used instead of the capacitor C4 to form a full bridge.

Even with such a configuration, the energy stored in the second inductor L2 is a closed loop f from the second inductor L2 to the diode D3 → DC power source E → diode D2 → second inductor L2. Therefore, the same effect as in the first embodiment is obtained, in which an excessive voltage is not generated across the second inductor L2.

FIG. 3 shows a third embodiment of the present invention. The configuration different from the first embodiment is that the pulse generating switch element S5 is specifically shown.

Here, the pulse generating switch element S5
Is composed of a triac TR1, and the triac TR1 is turned on when a trigger voltage is applied to the gate terminal. The trigger voltage input to the gate terminal is connected to the series circuit of the secondary winding and the discharge lamp in parallel with the series circuit of the charging resistor R1 and the trigger capacitor C5, and the SBS is connected across the trigger capacitor C5. Trigger element S6, etc.
The gate terminals of the triac TR1 are connected via the.

When the trigger capacitor C5 is charged by the resistor R1 and the voltage across the trigger capacitor C5 reaches the breakover voltage of the trigger element S6, the trigger element S6 is turned on and the charge accumulated in the trigger capacitor C5 is discharged. The triac TR1, which is the pulse generation switch element S5, shifts to the ON state.

When the triac TR1 shifts to the ON state, the electric charge of the pulse generating capacitor C2 is discharged, a high voltage is generated between the secondary windings of the pulse transformer PT1, and the discharge lamp La is started and lights up. When the discharge lamp La is turned on, the voltage across the discharge lamp La decreases, the voltage across the trigger capacitor C5 also decreases below the breakover voltage of the trigger element S6, and the generation of the high-voltage pulse voltage stops.

Therefore, in this embodiment, since the generation of the high-voltage pulse voltage can be automatically stopped when the discharge lamp La is turned on, there is an effect that the stopping means can be configured without adding a new circuit.

[0022]

As in the present invention, first and second switching elements connected in series at both ends of a DC power source, and first and second capacitors (switching elements connected in series at both ends of the DC power source). , And a secondary winding of a pulse transformer connected via a first inductor between the connection point of the first and second switching elements and the connection point of the first and second capacitors. A series circuit with a discharge lamp and a bypass capacitor connected in parallel with the series circuit of the secondary winding of the pulse transformer and the discharge lamp are provided, and the connection points of the first and second switching elements and the first and second switching elements. A pulse generating capacitor connected to the connection point of the second capacitor via a second inductor, a primary winding of a pulse transformer connected to both ends of the pulse generating capacitor, and a pulse generating switch element. When And then, is provided with a series circuit, in which a marked effect that while preventing a reduction in circuit efficiency, starting performance of the discharge lamp can be maintained.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a main part showing a second embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of essential parts showing a third embodiment of the present invention.

FIG. 4 is a circuit configuration diagram showing a conventional example of the present invention.

FIG. 5 is a circuit diagram of a main part of a conventional example of the present invention.

FIG. 6 is a circuit diagram of a main part showing a conventional example of the present invention.

[Explanation of symbols]

 E AC power supply S1 First switching element S2 Second switching element S3 Third switching element S4 Fourth switching element C3 First capacitor C4 Second capacitor L1 First inductor L2 Second inductor PT1 Pulse transformer n1 primary winding n2 secondary winding La discharge lamp C1 bypass capacitor C2 pulse generating capacitor S5 pulse generating switch element

Claims (2)

[Claims] 1. A direct current power supply, first and second switching elements connected in series at both ends of the direct current power supply, first and second capacitors connected in series at both ends of the direct current power supply, and first. , A series circuit of a secondary winding of a pulse transformer and a discharge lamp connected via a first inductor between a connection point of a second switching element and a connection point of first and second capacitors, A bypass capacitor connected in parallel with a series circuit of the secondary winding of the pulse transformer and the discharge lamp is provided, and the connection point of the first and second switching elements and the first,
A pulse generating capacitor connected to the connection point of the second capacitor via a second inductor, a primary winding of a pulse transformer connected to both ends of the pulse generating capacitor, and a pulse generating switch element. And a series circuit with the discharge lamp lighting device. 2. A DC power supply, first and second switching elements connected to both ends of the DC power supply, and third and fourth switching elements connected to both ends of the DC power supply.
A series of a secondary winding of a pulse transformer and a discharge lamp, which are connected via a first inductor between a connection point of first and second switching elements and a connection point of third and fourth switching elements. A circuit and a bypass capacitor connected in parallel with the series circuit of the secondary winding of the pulse transformer and the discharge lamp, and the connection point of the first and second switching elements and the third and fourth capacitors. A pulse generating capacitor connected between the connection point and the second inductor, and a series circuit of a primary winding of a pulse transformer connected to both ends of the pulse generating capacitor and a pulse generating switch element; A discharge lamp lighting device comprising: