JPH031496A - Fluorescent lamp lighting device - Google Patents

Abstract

PURPOSE:To accomplish a fluorescent lamp lighting device in small size and at a low cost by oscillating a timer IC when the charging voltage of a starter capacitor becomes a specified value, lighting the fluorescent lamp, and continuing the oscillation with the lamp current. CONSTITUTION:In a DC power supply circuit 20, the commercial AC voltage is rectified into a DC constant voltage, and timer IC 25 is oscillated with DC voltage. When the charging voltage of a starter capacitor charged with the DC voltage through a switching element 31 has attained a specified value, an IC 25 is oscillated with this voltage, and a fluorescent lamp 6 is lighted up. The current of the lamp 6 is impressed on the IC 25 as DC voltage through a feedback transformer 33, and the IC 25 continues oscillating. Now a feedback circuit is formed, and a lighting control circuit 36 is put in operation every time a touch switch 35 is touched by a human body to cause emission of the on/off control signal from the element 31 and the oscillation stop signal from the IC 25 in a specified sequence. Thus the lamp 6 is lighted with the aid of the feedback circuit, which eliminates use of a large power supply transformer to allow accomplishment of small sized and inexpensive lighting device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a passive type fluorescent lamp lighting device that lights a fluorescent lamp using a high frequency inverter by operating a touch switch.

[Conventional technology]

Fluorescent lamp lighting devices installed in fluorescent lamp lighting equipment such as lighting stands use a high-frequency inverter lighting method that modulates the commercial frequency to a high frequency of several tens of kilohertz to light the fluorescent lamp at high frequency.The light touch switch is lightly touched with a finger. Switches that can be used to turn on and off lamps are popular because they are easy to reduce in size and weight, have an excellent feel when operating the switch, and increase the commercial value of lighting equipment. A conventional example of this fluorescent lamp lighting device having a passive oscillation circuit is shown in FIG. 2, and will be explained.

In Figure 2, (1) is a commercial AC power supply, (2) is a DC power supply circuit that rectifies the AC voltage of the commercial AC power supply (1) and smoothes it to DC, and (3) is a passive oscillation circuit. . The oscillation circuit (3) is a timer IC (
4), an oscillation transistor (5) that performs switching operation by the oscillation of the timer IC (4), and an oscillation transistor (5).
) has an oscillation transformer (7) that oscillates to light the fluorescent lamp (6) at high frequency. (8) is an IC power supply circuit that steps down the AC voltage of the commercial AC power supply (1) using a power transformer (9) to obtain a DC voltage of 15V.
(10) is a touch switch, and (11) is a fluorescent lamp (
6) is a lighting control circuit that controls blinking, and is powered by the DC voltage of the IC power supply circuit (8).

The timer IC (4) oscillates when a DC voltage is applied from the IC power supply circuit (8) via the switching element (12), and the lighting control circuit controls the on/off of the switching element (12) that controls this oscillation. This is done using the control signal from (11). That is, the commercial AC power supply (1) is turned on,
When the switching element (12) is off and the fluorescent lamp (6) is in the off state, touch the touch switch (10) with one finger.
When touched twice, the lighting control circuit (11) operates and turns on the switching element (12).Then, the DC voltage of the IC power supply circuit (8) is applied to the timer IC (4). ) starts oscillating, the oscillation transistor (5) switches at that oscillation frequency, the oscillation transformer (7) oscillates, and the fluorescent lamp (6) lights up at high frequency. When touched once, the lighting control circuit (11) switches on the switching element (12).
) is switched from on to off, the oscillation of the timer IC (4) is stopped, and the fluorescent lamp (6) is turned off. A blinking operation of 0 or more is repeated every time the touch switch (10) is touched.

[Problem to be solved by the invention]

By the way, the passive oscillation circuit (3) of the lighting device allows the brightness of the fluorescent lamp (6) to be changed by changing the oscillation frequency of the timer IC (4). It has the advantage that it can be done easily and at low cost. However, in order to drive the timer IC (4), a relatively large capacity DC power source is required, and an IC power supply circuit (IC power supply circuit) that steps down and rectifies the commercial AC power source (1) with a power transformer (9). 8), but 10
Power transformer that steps down 0■ commercial AC to 15V (9)
This requires a large and expensive device, which makes it difficult to downsize and reduce the cost of the lighting device as a whole, making it difficult to downsize the lighting equipment in which this lighting device is mounted. Particularly in small lighting fixtures such as lighting stands, the above-mentioned fluorescent lamp lighting device makes it difficult to modify the lighting fixtures into smaller and more compact designs.

The present invention has been made in view of these problems, and an object of the present invention is to provide a compact and low-cost separately excited high frequency inverter lighting system fluorescent lamp lighting device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a DC power supply circuit that rectifies a commercial AC/power supply voltage to a constant DC voltage, and a separately excited oscillation system that lights a fluorescent lamp at the oscillation frequency of a timer IC that oscillates when DC voltage is applied. an IC startup circuit that instantaneously oscillates the timer IC at a charging voltage when a charging voltage of a startup capacitor charged via a switching element with the DC voltage of the DC power supply circuit reaches a predetermined value;
A feedback transformer has a secondary winding in which a voltage is induced by the current in the primary winding through which the lamp current of a lit fluorescent lamp flows, and a timer IC that rectifies the voltage induced in the secondary winding of the feedback transformer. A feedback circuit that has a rectifier circuit that is applied as a DC power supply voltage to continue the oscillation of the timer IC, and an on/off control signal for the switching element of the IC startup circuit and an oscillation circuit that operates every time a human body touches the touch switch. timer IC
and a lighting control circuit that outputs the oscillation stop signals in a predetermined order.

[Effect]

The starting capacitor of the IC starting circuit is charged with the DC voltage of the DC power supply circuit that rectifies the commercial AC, and when this charging voltage reaches a predetermined level, the timer IC is momentarily oscillated to turn on the fluorescent lamp momentarily. By making the timer IC continue to oscillate with the voltage induced in the secondary winding of the feedback transformer of the feedback circuit by the lamp current at this time, a special large-capacity power supply transformer is used to make the timer IC oscillate. This eliminates the need for an IC power supply circuit.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to FIG.

In Fig. 1, (20) is a DC power supply circuit, and when a commercial AC power supply (1) is applied via a noise filter circuit (21), it is full-wave rectified by a full-wave rectification circuit (22).
Smooth the voltage to a constant voltage using a smoothing capacitor (23). (24)
is a passive type oscillation circuit, which includes a timer IC (25) that oscillates when a DC voltage is applied, an oscillation transistor (26) that performs switching operation due to the oscillation of the timer IC (25), and a switching operation of the oscillation transistor (26). It has an oscillation transformer (27) that oscillates to light the fluorescent lamp (6). (28) is an IC startup circuit that instantaneously oscillates the timer IC (25), which connects a series circuit of a startup capacitor (29), a diode (30), and a switching element such as the first transistor (31) to a DC power supply circuit (20). and the power terminal of the timer IC (25).

(32) is a feedback circuit that continues the oscillation of the instantaneous oscillation of the timer IC (25), and includes a feedback transformer (33) and a rectifier circuit (34). The feedback transformer (33) has a primary winding N as a current limiting means through which the lamp current flows, and a secondary winding N2 in which an alternating current voltage is induced by the current flowing in the primary winding N1. ) rectifies the AC voltage induced in the secondary winding N1 of the feedback transformer (33) using two rectifier diodes D, , D2 and a capacitor C1, and applies the rectified voltage to the power supply terminal of the timer IC (25) as a power supply voltage.

(35) is a touch switch, and (36) is an on/off control signal for the first transistor (31) of the IC starting circuit (28) and a timer IC (25) each time a finger touches the touch switch (35). This is a lighting control circuit that sequentially outputs oscillation stop signals.

The lighting control circuit (36) includes, for example, a touch switch (35).
), which outputs one clock pulse each time a finger touches the circuit (37), and outputs one clock pulse to three first to third output terminals Q1 to Q3 each time one clock pulse is input from the signal conversion circuit (37). It has a Licade count IC (3B) that sequentially outputs voltage high level control signals, and these two step down the DC voltage of the DC power supply circuit (20) to 12V with a resistor (39) and a Zener diode (40). When a high-level signal is output to the first terminal Q1 of the Licade Count IC (38), which operates using the constant voltage as the power supply, the second transistor (41) turns on and shorts the capacitor C2.
When the oscillation of the timer IC (25) stops and a high level signal is output to the next second output terminal Q2, the first transistor (31) of the IC starting circuit (28) turns on and the starting capacitor ( 29) starts charging and a high-level signal is output to the third output terminal Q, this signal is input as a reset signal to the reset terminal R of the Ricade Count IC (3B), and the Ricade Count IC (3B) (38
) is reset to the initial state in which the first output terminal Q becomes high level.

Next, the operation procedure of the above embodiment will be explained.

Lighting control circuit (36) Glue counter IC (38)
When the timer IC (25) is in its initial state and the timer IC (25) is in an oscillation-stopped state, when the light is off, touch the touch switch (35) once with your finger. Then, one clock pulse is output from the signal conversion circuit (37) to the ricade count IC (38), a high level signal is transferred from the first output terminal Q1 to the second output terminal Q2, and the first output terminal Q is By going low level, the second transistor (41) is turned off and the timer IC (25) can oscillate, and at the same time, the first transistor (31) of the IC starting circuit (28) is turned off by the high level signal of the second output terminal Q2. Turn on. When turned on, the starting capacitor (28) is charged with the DC voltage of the DC power supply circuit (20), and the timer IC (25) oscillates at the moment the charging voltage reaches the oscillation voltage of the timer IC (25).

This oscillation is an instantaneous oscillation until the charging of the starting capacitor (29) is completed, and this instantaneous oscillation causes the oscillation transistor (26
) performs a switching operation, the oscillation transformer (27) oscillates, the fluorescent lamp (6) momentarily lights up, and a lamp current flows through the primary winding N of the feedback transformer (33).

Then, a voltage is induced in the secondary winding N2, and this voltage is rectified by the rectifier circuit (34) and applied as a power supply voltage to the timer IC (25), so that the timer IC (25) continues to oscillate. The fluorescent lamp (6) remains lit.

Next, when you touch the touch switch (35) with your finger once, the second output terminal Q2 of the Licade Count IC (38) is inverted to low level, and instead a high level signal is output to the third output terminal Q3, causing a reset. The code count IC (38) is reset to the initial state, the second transistor (41) is turned on, the oscillation of the timer IC (25) is stopped, and the fluorescent lamp (6) is turned off. At the same time, IC startup circuit (28)
The first transistor (31) is turned off, and the charging charge of the starting capacitor (29) is transferred to the resistor (42) connected in parallel.
is discharged through the timer IC when the next lamp is lit.
Prepare for the activation of (25).

The above fluorescent lamp (6) flashes when the touch switch (35)
) is repeated each time you touch the finger once. Further, when the oscillation circuit (24) is in an oscillation state, the fluorescent lamp (6)
When no load occurs, such as when the lamp is removed from the socket, no lamp current flows, so the feedback transformer (33
) is no longer induced in the secondary winding N2, the oscillation of the timer IC (25) automatically stops, and abnormal oscillation of the oscillation circuit (24) during no-load conditions is prevented.

〔Effect of the invention〕

As in the present invention, the timer IC of a separately excited oscillation circuit using a timer IC is instantaneously oscillated with the voltage at which the starting capacitor is charged with the DC voltage obtained by rectifying the commercial AC power supply, and this instantaneous oscillation is achieved. The voltage induced in the secondary winding of the feedback transformer by the lamp current flowing in the lamp is fed back to the timer IC, and the timer IC continues to oscillate.
The power supply circuit can be configured without using a special power transformer, and the entire lighting device can be made smaller and lower in cost. Particularly in a fluorescent lamp lighting device mounted on a small lighting fixture such as a lighting stand, miniaturization allows various modifications to the design of the lighting fixture.

[Brief explanation of drawings]

FIG. 1 is a lighting circuit diagram showing an embodiment of the present invention. FIG. 2 is a lighting circuit diagram of a conventional fluorescent lamp lighting device. (1”) - Commercial AC power supply, (6) - Fluorescent lamp, (
20) - DC power supply circuit, (24) - oscillation circuit, (25
)-m-timer IC1 (28)--IC starting circuit,
(29) - Starting capacitor, (31) - Switching element, (32) - Feedback circuit, (33) - Feedback transformer, N, -1
Next winding, N2--secondary winding, (34)--rectifier circuit, (35)--touch switch, (36)--lighting control circuit.

Claims (1)

[Claims] (1) A DC power supply circuit that rectifies a commercial AC/power supply voltage to a constant DC voltage, a separately excited oscillation circuit that lights a fluorescent lamp at the oscillation frequency of a timer IC that oscillates when DC voltage is applied, and the DC power supply circuit. an IC startup circuit that instantaneously oscillates the timer IC at a charging voltage when the charging voltage of a startup capacitor charged via a switching element reaches a predetermined value with a DC voltage of A feedback transformer has a secondary winding in which a voltage is induced by a flowing current in the primary winding, and the voltage induced in the secondary winding of the feedback transformer is rectified and applied as a DC power supply voltage to a timer IC, Timer IC
A feedback circuit has a rectifier circuit that continues the oscillation of the I
1. A fluorescent lamp lighting device comprising a lighting control circuit that outputs an on/off control signal for a switching element of a C starter circuit and an oscillation stop signal for a timer IC of an oscillation circuit in a predetermined order.