JPH02257599A - Electric discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To stabilize the starting characteristics of the title device by connecting a reset circuit comprising a differentiating circuit and a short- circuiting circuit to each of the capacitors of both a soft starter circuit and an entire light emission starter circuit via a diode. CONSTITUTION:A rectifier circuit(REC) is connected to an a.c. supply(AC). A reset circuit comprising a differentiating circuit made up of a resistor R21 and a capacitor C21, and also a short-circuiting circuit made up of a short- circuiting transistor Q4 is connected to the rectifier circuit(REC). The short- circuiting circuit is connected further to a time-limiting capacitor C7 in a soft starter circuit via a diode D21, while being connected to a capacitor C8 in an entire light emission starter circuit via a diode D22. As a result of this circuit structure, turning on a lighting switch causes the reset circuit to be operated, and therefore an ordinary lighting condition controlled by the soft starter circuit is allowed to set in without fail for providing stable starting characteristics of the title device.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a discharge lamp lighting device that is equipped with a soft start circuit and a full-light starting circuit and is capable of switching between full-light and dimming.

Conventional technology In general, this type of discharge lamp lighting circuit is provided with a soft start circuit that preheats the filament by setting a certain time when the power is turned on, and an all-light starting circuit that sets a time for full-light starting. ing.

In these soft start circuits and all-optical start circuits, time constant circuits including capacitors are used as timers for setting respective operating times.

Problems to be Solved by the Invention When the lighting switch is opened and closed in the dimming mode, the capacitors of the time constant circuits of the soft start circuit and the all-light starting circuit are in a charged state, so the adjustment occurs at the same time as the lighting switch is turned on. The discharge lamp does not turn on due to the light condition.

Therefore, in this case as well, only the capacitor of the time constant circuit of the all-light starting circuit is reset so that the discharge lamp is lit. As a result, the discharge lamp is turned on at the same time as the lighting switch is turned on, and after passing through a full light state for a certain period of time, it shifts to a dimming state. However, due to the combination of SS switches (try hooks), etc., the lighting state is not stable, and a so-called off-light condition occurs in which the discharge lamp blinks.

Means for Solving the Problem In a fluorescent lamp electronic lighting device that is equipped with a soft start circuit and a full-light starting circuit and is configured to switch between full-light and dimming, a differential circuit and a short circuit connected to the differential circuit are used. A reset circuit directly connected to the power supply circuit was connected to the capacitors of the soft start circuit and the all-optical start circuit via diodes, respectively.

When the operation lighting switch is turned on, the reset circuit operates and the capacitors of the time constant circuits of the soft start circuit and all-light starting circuit are discharged, so the normal lighting state under the control of the soft start circuit always starts. Therefore, even if the lighting switch is turned on immediately after being turned off by the lighting switch in dimming mode, both the capacitors of the time constant circuit of the soft start circuit and all-light starting circuit are discharged by the reset circuit. This makes it possible to obtain stable starting characteristics.

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

First, a rectifier circuit REC is connected to the alternating current power supply AC, and a smoothing capacitor C1 is connected to the rectifier circuit RFC. A primary winding N of the leakage transformer TR is connected to such a rectifier circuit RFC. A capacitor C3 is connected to the secondary winding N, and a primary side resonant circuit is formed by this capacitor C1 and the negative secondary winding N1.

Next, a lamp LT and a capacitor Cl are connected to the secondary winding N of the leakage transformer TR, and a series circuit of a capacitor C1 and a current transformer CT, and a bypass resistor RI I in parallel thereto are connected to the secondary winding N of the leakage transformer TR. are connected. The secondary winding N3 and the capacitor CI m
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 RFC, 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
1. A diode D8, a series circuit of a capacitor CIS, and an ON time control transistor Tr are connected in parallel. Further, a resistor Rl 4 and a diode D are connected between the oscillation transistor Q and the current transformer CT for resetting the capacitor CI 1 and the capacitor CI 1. In this way, a current transformer feedback inverter circuit is formed.

Next, a resistor R8 and a capacitor C7 forming a time constant circuit of the 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 C2, and a Zener diode ZD is connected in parallel with these. Further, a variable resistor VR is connected to the collector of the control transistor Q, 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 Q is connected to the connection midpoint of a series circuit of a resistor R1 and a resistor R6 connected to the rectifier circuit REC.

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 R1, which is connected to the dimming power supply terminal T1, and the capacitor C.
s is connected to a time constant circuit.

A resistor RI l is connected in parallel to the capacitor C1.

Further, the rectifier circuit RFC includes a differential circuit including a resistor Rl and a capacitor Cl, a short-circuit transistor Q,
short circuit and are connected. A resistor Rms for maintaining the base potential is connected to the base of the shorting transistor Q4, and a resistor R0 is connected in parallel to this resistor R0 and the capacitor Cl1.

Therefore, at the emitter of the shorting transistor Q4,
With the anode facing the emitter side, a diode D11 and a diode D3 for backflow prevention are connected to the positive polarization of the capacitor C7 of the soft start circuit and the capacitor C1 of the all-optical start circuit, respectively. are connected.

In such a configuration, when the power is turned on, the resistor R1
A differentiating circuit between capacitor C1 and capacitor C4 operates to turn on shorting transistor Q4 for a short period of time.

As a result, the capacitor C7 of the soft start circuit and the capacitor C1 of the all-optical start circuit are short-circuited via the diode DIIIDM, and even if there is any accumulated charge, it is discharged and reset. Then, at the same time as the power is turned on, a voltage is applied to the base of the oscillation transistor Q3 via the starting resistor R4, and the oscillation transistor Q is turned on. As a result, the primary winding N1 of the transformer TR is energized, and an induced voltage is generated in the secondary winding N.

Due to the voltage induced in the secondary winding N2, a current flows through the current transformer CT, and the capacitor Cs s,
By charging C1m and discharging the charge of capacitor C12 and Cl1 by diode D and resistor RI4, ON/OFF of oscillation transistor Q is controlled, and lamp L
Driving power is supplied to T.

Therefore, based on the resonant frequency of the primary winding N1 of the transformer TR and the capacitor C1 connected to the rectifier circuit RFC together with the diode D1, the voltage CE applied to the oscillating transistor Q is calculated as shown in FIG. -b
A voltage is applied between them. As mentioned above, between b and c, capacitors CI 1 and CI 3 are charged, and capacitor Cl is connected to diode D and resistor Rl 4.
1 is the ON time of the oscillation transistor Q, which is set by discharging the charge of CI3. During this ON time, the second
As shown in the figure, the collector current Ic of the oscillation transistor Q changes.

Therefore, in the control circuit including the control transistor Q, a resistor R6 and a resistor R connected in series with the diode D3 are connected.
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 Q8.
, a resistor RI 1 and a resistor RI m connected to the collectors of
A voltage corresponding to the voltage at the base of the control transistor Q8 generated at the midpoint of the connection with the ON time control transistor Tr
By changing the constants of the parallel circuits such as capacitor C0 and capacitor C0, the ON time of the oscillation transistor Q, specifically, the time between d and c in FIG. 2 is changed.

When the power is turned on, the resistor R1 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 C7 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 capacitor C7 has a small capacitance, sufficient charging time can be obtained, thereby providing the necessary function as a soft start circuit.

Also, in dimming mode, the lighting switch is turned off,
Immediately after that, the lighting switch may be turned on again. In this case, capacitor C7 of the soft start circuit
Since the capacitor C1 and the all-light starting circuit are charged, a certain amount of charge is accumulated, but the differential circuit between the resistor RM1 and the capacitor CII operates and the shorting transistor Q4 is turned on for a short period of time. By this, diode D
The capacitor C1 of the soft-start circuit and the capacitor C1 of the all-optical starting circuit are short-circuited via I I I D l m to discharge the accumulated charge, and the soft-start circuit and the all-optical starting circuit are reset. Therefore, reliable starting characteristics can be obtained.

In addition, the current transformer CT connected to the lamp LT
A capacitor C1 is connected to the capacitor C1, 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 series circuit between the current transformer CT and the capacitor C0. DC components generated due to unbalance of the lamp LT, end of life, etc., pass through the bypass resistor RII side.

Effects of the Invention As described above, the present invention provides an electronic lighting device for a fluorescent lamp which is equipped with a soft start circuit and a full-light starting circuit and is configured to switch between full-light and dimming. The reset circuit, which is connected directly to the power supply circuit as a short circuit, is connected to the capacitors of the soft start circuit and all-optical starting circuit through diodes, so that when the lighting switch is turned on, the reset circuit is activated. can discharge the capacitors of the time constant circuits of the soft-start circuit and the all-light starting circuit, which always initiates the normal lighting condition controlled by the soft-start circuit, and therefore the lighting in dimming mode. Even if the lighting switch is turned on immediately after the light is turned off by the switch, the reset circuit discharges both the capacitors of the time constant circuit of the soft start circuit and the all-light starting circuit, thereby ensuring stable starting characteristics. This has the effect of being able to obtain the following.

FIG. 3 is a waveform diagram showing the charging voltage for the time constant circuit of the soft start circuit.

Rl l I Cm +... Differential circuit, Q,... Short circuit, C7... Time constant circuit, C1... Time constant circuit, D 111 D I! ...Diode applicant Toshiba Electric Materials Corporation

[Brief explanation of drawings]

Claims (1)

[Claims] Equipped with a soft start circuit and an all-optical starting circuit, the all-optical
In a fluorescent lamp electronic lighting device that performs dimming switching, a reset circuit consisting of a differential circuit and a short circuit connected to the differential circuit and directly connected to the power supply circuit is combined with the soft start circuit and the all-light starting circuit. A discharge lamp lighting device characterized in that each of the capacitors is connected via a diode.