JPH02257598A - Electric discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To decrease the capacity of a capacitor for a timer by connecting a time constant circuit in a soft soft starting circuit to a half-wave rectifier circuit connected to an input AC line. CONSTITUTION:A rectifier circuit(REC) is connected to an alternating current supply(AC). A time constant circuit comprising a resistor R1 and a capacitor C7, which is connected between the alternating current supply(AC) and one side of the rectifier circuit(REC), is allowed to regulate the operation time of a soft starting circuit which transfers to the entire light emitting condition after the lapse of a specified time based on the output of the time constant circuit. The capacitor C7 in the time constant circuit needs charging itself with a half-wave rectified voltage. For this reason, charging and discharging are repeated to lengthen the time for charging the capacitor so that the capacitor requires only capacity of less than half the capacity thereof required in use of a direct current for miniaturization of the capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a discharge lamp lighting device, and more particularly to a discharge lamp equipped with a soft start circuit and a full-light starting circuit to switch between full-light and dimming. This invention relates to a lighting device.

2. Description of the Related Art Generally, in this type of discharge lamp lighting circuit, a time constant circuit for setting the operating time of a soft start circuit is connected to a rectifier circuit.

Problems to be Solved by the Invention Since the power source of the time constant circuit of the soft start circuit is the DC output of the rectifier circuit, the timer capacitor constituting the time constant circuit needs to have a large capacity of about 220 μF. Therefore, it is disadvantageous in terms of cost and also becomes an obstacle to miniaturization of the device.

Means for Solving the Problem In a discharge lamp lighting device which is equipped with a soft start circuit and an all-light starting circuit and is configured to switch between all-intensity and dimming, the time constant circuit of the soft start circuit is connected to an input AC line. connected to a half-wave rectified waveform circuit.

The power supply that charges the capacitor of the time constant circuit of the soft start circuit is a half-wave rectified waveform power supply, so it repeats charging and discharging, which extends the charging time, so the capacitor capacity is reduced to less than half. can do.

Example An embodiment of the present invention will be described based on the drawings.

First, a rectifier circuit RFC is connected to the alternating current power supply AC, and a smoothing capacitor C6 is connected to the rectifier circuit REC. A primary winding N of the leakage transformer TR is connected to such a rectifier circuit REC. A capacitor C is connected to the secondary winding N, and a primary side resonant circuit is formed by this capacitor C1 and the secondary winding N.

Next, a lamp LT and a capacitor CI l are connected to the secondary winding N of the leakage transformer TR, and a series circuit of a capacitor Cte and a current transformer CT, and a bypass resistor R11 in parallel thereto are connected. is connected. the secondary winding N, and the capacitor CI 1
A secondary side resonant circuit is formed by this.

Further, an oscillation transistor Q forming an inverter circuit is connected between the primary winding N of the leakage transformer TR and the rectifier circuit REC, and a starting resistor R4 is connected to the base of the oscillation transistor Q. It is connected. A current transformer CT is interposed between the base and emitter of this oscillation transistor Q, and a capacitor C1
□, a diode D1, a series circuit of a capacitor 0.3, and an ON time control transistor Tr are connected in parallel. Further, the capacitor C is connected between the oscillation transistor Q and the current transformer CT.
A resistor Rl 4 and a diode D are connected for resetting t x and the capacitor CI 3. In this way, a current transformer feedback inverter circuit is formed.

Next, a resistor R1 and a capacitor C7 forming a time constant circuit of a soft start circuit are connected between the AC power supply AC and one side of the rectifier circuit REC. A resistor R10 and a control transistor Q are connected in series to the midpoint between the resistor R1 and the capacitor C7, and a Zener diode ZD is connected in parallel thereto. Further, a variable resistor VR is connected to the collector of the control transistor Q3, and the variable resistor V
The gate of the ON time control transistor Tr is connected to R.

Further, the base of the control transistor Q3 is connected to a connection midpoint of a series circuit of a resistor R8 and a resistor R1 connected to the rectifier circuit RFC.

Furthermore, a control transistor Q constituting an all-optical starting circuit,
A control transistor Q is provided.

The collector of the control transistor Q is connected to the collector of the control transistor Q. A Zener diode ZD is provided at the base of the control transistor Q.

The Zener diode ZD is connected to the resistor Rl and the capacitor C connected to the dimming power supply terminal T1.
1 and is connected to a time constant circuit.

A resistor R1m is connected in parallel to the capacitor C1.

In such a configuration, when the power is turned on, the oscillation transistor Q first passes through the starting resistor R1.

A voltage is applied to the base of the oscillating transistor Q,
turns on. As a result, the primary winding N of the transformer TR,
is energized, and an induced voltage is generated in the secondary winding N8. Due to the induced voltage induced in this secondary winding N, the current
Current flows through the transformer CT, and the capacitors CI m, CI
By charging S and discharging the charges of capacitors C11 and C11 by diode Ds and resistor Rl4, ON/OFF of oscillation transistor Q is controlled, and driving power is supplied to lamp LT.

Therefore, based on the resonance frequency of the diode D, the primary winding N of the transformer TR connected to the rectifier circuit RFC, and the capacitor C5, the voltage VCE applied to the oscillation transistor Q1 is determined as shown in FIG. A voltage is applied between a and b. As mentioned above, between b and c, capacitor C38 and CI 3 are charged, diode D and resistor RI 4 are connected to capacitor Ct
Oscillation transistor Q set by discharging a charge of 1
, 08 hours. During this ON time, as shown in FIG. 2, the collector current Ic of the oscillation transistor Q1 changes.

Therefore, in the control circuit including the control transistor Q3, the resistor R1 and the resistor R are connected in series to the diode D.
1. A voltage divided by the resistor R1 and the variable resistor VR and smoothed by the capacitor C1 is applied to the base of the control transistor Q3, and the voltage is applied to the base of the control transistor Q8.
A voltage corresponding to the voltage at the base of the control transistor Q2 generated at the midpoint of the connection between the resistor Rl 1 and the resistor R+ 1 connected to the collector of the transistor switches the ON time control transistor Tr, and the capacitor C1 and the capacitor CIS By changing the constant of the parallel circuit of , the time of the oscillation transistor Q, specifically, the time between d and c in FIG. 2 is changed.

When the power is turned on, resistor R8 and capacitor C
1 is operating, the control voltage to the ON time control transistor Tr is for filament preheating, and the resistor R
When a predetermined time period based on a time constant circuit formed by C.1 and capacitor C6 has elapsed, the state shifts to full light state. In the soft start circuit exhibiting such an operation, the charging voltage to the capacitor C7 of the time constant circuit is a half-wave rectified voltage, as shown in FIG. 3, and charging and discharging are repeated.

Therefore, even if the capacitance of the capacitor C1 is small, sufficient charging time can be obtained, thereby providing the necessary function as a soft start circuit.

Also, the current transformer CT connected to the lamp LT
A capacitor C8 is connected to the capacitor C8, and a bypass resistor RII is connected to these, but only the alternating current component when the lamp LT is turned on is passed through the current transformer CT and the capacitor C1, which series circuit side. A DC component generated due to unbalance of the lamp LT, end of life, etc. passes through the bypass resistor R11 side.

Effects of the Invention As described above, the present invention provides a discharge lamp lighting device that includes a soft start circuit and a full-light starting circuit and performs full-light/dimmer switching, in which a time constant circuit of the soft start circuit is input. Since it is connected to a half-wave rectified waveform circuit connected to the AC line, the power supply that charges the capacitor of the time constant circuit of the soft start circuit is a power supply with a half-wave rectified waveform, so it repeats charging and discharging. This has the effect of extending the charging time and reducing the capacitance of the capacitor.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a circuit diagram, Fig. 2 is a waveform diagram showing the relationship between the collector-emitter voltage and collector current of the oscillation transistor Q, and Fig. 3 is a soft start diagram. FIG. 3 is a waveform diagram showing a charging voltage for a time constant circuit of the circuit. AC...input AC line, RFC...rectifier circuit, C
1... Time constant circuit applicant Toshiba Electric Materials Corporation - Figures 2 and 3

Claims (1)

[Claims] In a discharge lamp lighting device that includes a soft start circuit and a full-light starting circuit and performs full-light/dimming switching, the time constant circuit of the soft start circuit is connected to a half-wave rectifier waveform circuit that is connected to an input AC line. A discharge lamp lighting device characterized by being connected to.