JPH0447440B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device for an AC discharge lamp that drives and lights an AC discharge lamp.

[Conventional technology]

2. Description of the Related Art Conventionally, an AC discharge lamp power supply device for lighting and driving an AC discharge lamp has a configuration approximately as shown in FIG. 3.

In the figure, reference numeral 1 denotes a start signal input terminal, to which a start signal output from a start signal output section (not shown) is supplied in response to a start operation such as turning on a start switch. Reference numeral 2 denotes a DC power supply, and 3 a switching regulator main circuit section, in which switching elements such as transistors are driven by switching signals at a high frequency of 20 to 100 KHz to convert the DC power supply 2 into a high frequency output.

Reference numeral 4 designates a current detection unit consisting of a current transformer or the like that detects the output current of a rectification and smoothing unit, which will be described later, and outputs a detection signal proportional to the output current, and 5 designates an output terminal of a reference signal generation unit (not shown). Outputs a constant level reference signal with opposite polarity to the detection signal. 6 is an adder that adds the reference signal of the output terminal 5 and the detection signal; 7 is a feedback amplifier whose non-inverting input terminal (+) is grounded and whose inverting input terminal (-) is connected to the adder 6;
The output of adder 6 is amplified and output. 8 is a PWM control section that is activated by the start signal and outputs a PWM control signal according to the output of the amplifier 7; 9 is an output control section that supplies a switching signal according to the PWM control signal to the main circuit section 3; do. 10
is a rectifying and smoothing section that rectifies and smoothes the output of the main circuit section 3.

Then, the feedback control circuit of the current detection section 4, amplifier 7, PWM control section 8, and output control section 9 causes the output current of the rectification and smoothing section 10 to be set to a constant value based on the reference signal, for example, the rated current of the discharge lamp described later. Feedback control is performed so that

11 is a clock generator that generates and outputs a low-frequency clock pulse of about 200 Hz; 12 is an inverter controller that repeatedly outputs an on/off control signal in synchronization with the clock pulse; and 13 is an inverter, which is a well-known transistor bridge configuration. Similar to the inverter, it is formed by bridge-connecting inverter switching elements such as transistors.
The on/off control signals cause the elements on one side of the bridge and the elements on the other side of the bridge to be driven by low frequency switching in opposite phases, and this driving converts the output of the rectifying and smoothing section 10 into alternating current. .

14 is an AC discharge lamp that is driven to be lit by applying a low-frequency AC output voltage of the inverter section 13; 15;
16 is an automatic reset type trigger switch whose one end is connected to the connection terminal 1, and 16 is a high-pressure starter section whose trigger terminal is connected to the other end of the trigger switch 15. When the trigger switch 15 is turned on, it is activated for a predetermined period of time and then released. A high frequency and high voltage is applied to the electric lamp 14 to reduce the load impedance of the discharge lamp 14.

Then, when a start signal is generated by the start operation, the input of this signal activates the PWM control section 8 to drive the regulator main circuit section 3, and a constant current is output from the rectifying and smoothing section 10 to be driven by the inverter section 13. The output of the rectifying and smoothing section 10 is
It is converted to a low frequency alternating current of about 200Hz, and the discharge lamp 1
The AC output voltage of the inverter section 13 is applied to 4.

At this time, the switch 15 is turned on by manual operation or automatic control, and the start signal is supplied as a trigger to the high-voltage starter section 16. As a result of this supply, the high-frequency output voltage of the high-voltage starter section 16 is superimposed on the AC output voltage of the inverter section 13. A high voltage is applied, and the discharge lamp 14 is arc-started and driven to be lit by this application.

Then, the high-voltage starter section 16 stops operating, and from then on, only the output voltage of the inverter section 13 is continuously applied, and the discharge lamp 14 continues to be lit.

[Problem that the invention seeks to solve]

In the case of the conventional power supply device, since only AC lighting drive is performed, variations in lighting characteristics depending on the distance between the electrodes of the discharge lamp 14 used, the internal vapor pressure, etc., especially when the applied voltage of the discharge lamp 14 is changed when lighting the discharge lamp 14. When a zero-crossing point of the output of the inverter section 13 occurs and the energy decreases, there is a problem that lighting failure is likely to occur due to arc breakage at this timing.

Since the high-voltage starter section 16 is activated every time lighting fails, the surface of the electrodes of the discharge lamp 14 becomes rough and darkened due to sputtering, leading to deterioration of the electrodes of the discharge lamp 14 and shortening the life of the discharge lamp 14. There is a problem.

It is an object of the present invention to prevent lighting failure due to variations in lighting characteristics of a discharge lamp with a simple configuration, and to suppress polarization of the discharge lamp.

[Means to solve the problem]

In order to achieve the above object, the AC discharge lamp power supply device of the present invention includes a start signal output section that outputs a start signal in response to a start operation, and a switching signal for high output control for a predetermined period of time from input of the start signal. a switching regulator main circuit section that converts a DC power source into a high frequency output by high frequency switching drive based on the output signal of the output control section; a rectifying and smoothing section that rectifies and smoothes the output of the regulator main circuit section; an inverter control section that outputs an on control signal for a predetermined period of time from input of the start signal, and then repeatedly outputs an on and off control signal; and an inverter control section that repeatedly outputs an on and off control signal, and the on control signal an inverter section that outputs the output of the rectifying and smoothing section without conversion and converting the output of the rectifying and smoothing section into alternating current through low frequency switching drive based on the on/off control signal; The lamp includes: an AC discharge lamp that is lit and driven by applying an output voltage of an inverter; and a high-voltage starter that applies a high voltage to the discharge lamp in a superimposed manner for a predetermined period of time in response to input of the start signal.

[Effect]

In the power supply device of the present invention configured as described above, immediately after the start signal is input, a high frequency high current is output from the switching regulator main circuit section by the high output control switching signal of the output control section. The high frequency and high current of this regulator main circuit section is converted into direct current by the rectifying and smoothing section.

At this time, the output of the rectifying and smoothing section is directly supplied to the discharge lamp via the inverter section by an ON control signal from the inverter control section.

At the same time, the high voltage of the high voltage starter section is also superimposedly applied to the discharge lamp.

In addition, since the output of the inverter is a large DC output with no zero-crossing points, sufficient energy is always supplied to the discharge lamp at the start of lighting, preventing lighting failures that occur with conventional AC lighting drive. , the discharge lamp can be lit reliably, and deterioration of the electrodes of the discharge lamp can be suppressed.

〔Example〕

Next, one embodiment will be described with reference to FIGS. 1 and 2.

In FIG. 1, the same symbols as in FIG. 3 indicate the same or equivalent parts.

Then, two monostable multivibrators (hereinafter referred to as mono-multi) 17 and 18 are added, and the trigger terminals of both mono-multi vibrators 17 and 18 are connected to the start signal input terminal 1, and the t _s shown in FIG. Both monomultis 17 and 18 are activated by the rising edge of the start signal at the time, and based on this activation, the
The output signal of the monomulti 17 is added to the adder 6.

At this time, since the output signal of the monomulti 17 has the same polarity as the reference signal of the output terminal 5, the reference signal equivalently increases by the output signal of the monomulti 17, and the monomulti 17 operates based on this increase. During time T1, a switching signal for high output control is outputted from the output control unit 9 to make the output current of the regulator main circuit unit 3 as high as twice the rated current of the discharge lamp 14, and then the monomulti 1
7 is turned off, and the output of the output control section 9 is switched to a low output control switching signal that makes the output current of the regulator main circuit section 3 as low as the rated current of the discharge lamp 14, similar to conventional control.

Furthermore, the output shown in FIG.
During the T2 period in which the clock pulse is activated, it is held at a high level state, for example, as shown in FIG.

Then, the output of the clock generator 11 and the start signal are input to the AND gate 19, and the output of the inverter controller 12 is set as an ON control signal for the first time T2 by the output of the AND gate 19 shown in FIG. The signal prohibits switching of the inverter section 13, and then an on/off control signal for the clock pulse period is supplied to the inverter section 13.
Switching is driven at a low frequency of about 200Hz.

Furthermore, the output of the monomulti 18 is also supplied to the trigger terminal of the high-voltage starter section 16, and the high-voltage starter section 16 is operated for the time T2.

Therefore, when a start signal is generated by a start operation, the monomultis 17 and 18 are activated, and the output control section 9 outputs a switching signal for high output control due to the operation of the monomulti 17, and based on this signal, the start signal is output. from the leading edge of
T1 time is from regulator main circuit section 3 to discharge lamp 1.
A high frequency current approximately twice the rating of No. 4 is output, and this current is rectified and smoothed by the rectification and smoothing section 10.

In addition, due to the operation of the monomulti 18, an ON control signal is output from the inverter control unit 12, and based on this control signal, the inverter unit 13 operates one or the other opposing 2 for T2 time from the leading edge of the start signal.
The side switching elements are held in the on state, and the large DC output of the rectifying and smoothing section 10 is directly transmitted to the discharge lamp 1 through the on-state switching elements on the two sides.
4.

Furthermore, the T2 time from the leading edge of the start signal is
The high pressure starter section 16 is activated by the operation of the monomulti 18.
The high frequency high voltage of the high voltage starter section 16 is superimposed on the DC voltage from the rectifying and smoothing section 10 via the inverter section 13 and is applied to the discharge lamp 14 .

Immediately after the start signal is input, a large DC current approximately twice the rated value is supplied from the inverter unit 13 to the discharge lamp 14, and the lighting starts without a zero-crossing point occurring as in the case of conventional AC lighting drive. Sufficient energy is always supplied to the discharge lamp 14.
To surely light a discharge lamp 14 without failure in lighting, regardless of variations in lighting characteristics.

Incidentally, after the T1 and T2 times have elapsed, the outputs of the monomultis 17 and 18 are inverted and turned off, respectively.

Therefore, after the time T1 has elapsed, the output control section 9 outputs a switching signal for low output control similar to conventional control, and the regulator main circuit section 3 outputs a high frequency current approximately equal to the rated current of the discharge lamp 14.
This output is rectified and smoothed by the rectification and smoothing section 10.

In addition, after the T2 time elapses, the inverter control unit 1
The output signal of 2 is switched to an on/off control signal,
The inverter section 13 is driven by low frequency switching.

By this drive, the inverter section 13 converts the output direct current of the rectifying and smoothing section 10 into a low frequency alternating current of about 200 Hz and supplies it to the discharge lamp 14.

At this time, the high-voltage starter section 16 stops operating, and the lit discharge lamp 14 is maintained in a lit state by being supplied with only an alternating current of approximately the rated current from the inverter section 13.

Then, until the start signal is turned off, only the alternating current from the inverter section 13 continues to be supplied, and the discharge lamp 14 continues to be lit.

By the way, the operating time of Mono Multi 17 and 18
Assuming that T1 and T2 are T1>T2 and the rated current of the discharge lamp 14 is I, the current waveform supplied to the discharge lamp 14 via the inverter section 13 is as shown in FIG. 2a.

It goes without saying that the same effect can be obtained even if T1≦T2 is set.

In addition, in the above embodiment, two monomulti 1
7 and 18 are provided, however, the output of one monomultiple may be supplied to the adder 6, the clock generating section 11, and the high voltage starter section 16.

Furthermore, it goes without saying that the DC power supply 2 may have a circuit configuration that rectifies and smoothes alternating current.

〔Effect of the invention〕

Since this invention is configured as described above, it produces the effects described below.

When the lighting starts immediately after the output of the start signal starts, the output of the switching main circuit is increased by the high output switching control signal of the output control section to increase the output of the rectification and smoothing section, and the on control of the inverter control section is also performed. The large DC output of the rectifier and smoothing unit is directly supplied from the inverter unit to the discharge lamp according to the signal, and then the output of the inverter unit is switched to AC for sustaining lighting, so a simple configuration that switches the output of one inverter unit is used. , supplies a large current to the discharge lamp without causing a zero-crossing point, and reliably lights the discharge lamp with sufficient energy without failure, regardless of the lighting characteristics based on the distance between the electrodes of the discharge lamp or variations in internal vapor pressure. be able to.

In addition, it is possible to prevent the repetitive operation of the high-voltage starter section due to lighting errors in conventional AC lighting drive, and to suppress deterioration of the electrodes of the discharge lamp. Compared to this, the life of the lamp can be extended, and the effect is extremely large.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the AC discharge lamp power supply device of the present invention, FIG. 1 is a block diagram, FIGS. 2 a to f are waveform diagrams of various parts, and FIG. 3 is a conventional example. It is a block diagram. 2... DC power supply, 3... Switching regulator main circuit section, 9... Output control section, 12... Inverter control section, 13... Inverter section, 14...
Discharge lamp, 16...High voltage starter section.

Claims (1)

[Scope of Claims] 1. A start signal output unit that outputs a start signal in response to a start operation; and an output that outputs a switching signal for high output control for a predetermined time from input of the start signal, and then outputs a switching signal for low output control. a control section; a switching regulator main circuit section that converts DC power into a high frequency output by high frequency switching drive based on an output signal of the output control section; and a rectifying and smoothing section that rectifies and smoothes the output of the regulator main circuit section. an inverter control section that outputs an ON control signal for a predetermined period of time from input of the start signal, and then repeatedly outputs ON and OFF control signals; , an inverter section that converts the output of the rectifying and smoothing section into alternating current and outputs it by low-frequency switching drive based on an off control signal; and an alternating current that is connected to the inverter section and is driven to light by applying the output voltage of the inverter section. 1. A power supply device for an AC discharge lamp, comprising: a discharge lamp; and a high-voltage starter section that applies a high voltage in a superimposed manner to the discharge lamp for a predetermined period of time upon input of the start signal.