JPH1027696A - Power source for separately excited inverter type sign lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make flow angle control dimming and high speed on/off lighting capable. SOLUTION: In a voltage section of small rectifying output, a Schmitt gate 55 is not triggered, a transistor 56 is turned off, an FET 51 is turned on, a capacitor 31 is rapidly charged through a current limiting resistor 52. Voltage of the capacitor 31 is generated in a start level Ec or more, the Schmidt gate 55 is triggered, the transistor 56 is turned on, the FET 51 is turned off. A switching control signal is generated from an IC 45, switching elements 21, 22 are alternately on/off controlled. Even when a switch 13 is on/off turned for flow angle control dimming and high speed flickering, corresponding to this operation, high frequency power is on/off controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention rectifies commercial AC power, converts the rectified output into high-frequency high-frequency power by a separately-excited inverter, and uses the high-voltage high-frequency power to neon tubes,
The present invention relates to a power supply for lighting a sign lamp such as an argon tube.

[0002]

2. Description of the Related Art Conventionally, in order to light a sign lamp, commercial AC power is boosted by a transformer and applied to the sign lamp. However, since the step-up transformer becomes large, a method of once rectifying the commercial AC power, converting the commercial AC power to high frequency power of about 20 kHz to 50 kHz, boosting the voltage, and applying it to a sign lamp has been partially commercialized. ing. In this case, the step-up transformer can be made significantly smaller than before.

If a self-excited inverter is used as this inverter, load fluctuations, that is, the number of illuminated sign lights will differ, or the oscillation frequency will fluctuate relatively largely due to fluctuations in the input voltage. There was a problem that the brightness changed greatly. As a countermeasure, a separately-excited inverter having a control signal generation unit for controlling the switching element to be turned on / off is used, especially for medium and high capacity applications.

FIG. 5 shows a conventional sign lamp power supply using the separately excited inverter. The input terminals 11 and 12 are connected to a commercial AC power supply 14 through a dimming or blinking AC switch 13. A full-wave rectifier 15 is connected between the input terminals 11 and 12, a series connection of capacitors 18 and 19 is connected between output terminals 16 and 17 of the full-wave rectifier 15, and switching elements 21 and 22 such as transistors and FETs are connected. A series connection is connected. The transformer 2 is connected between the connection point of the capacitors 18 and 19 and the connection point of the switching elements 21 and 22.
3 is connected, output terminals 26 and 27 are provided at both ends of a secondary winding 25 of the transformer 23, and a sign lamp 2 such as a neon tube or an argon tube is provided between the output terminals 26 and 27.
8 is connected.

[0005] The charging resistor 2 is connected to the output terminal 16 of the rectifier 15.
The other end of the charging resistor 29 is connected to the output terminal 17 of the rectifier 15 through the starting capacitor 31. A connection point 32 between the resistor 29 and the capacitor 31 is connected to a non-inverting input terminal of a starting level detector 33, and a reference power supply 34 is connected to an inverting input terminal of the starting level detector 33.
The output side of the starting level detector 33 is connected to one input terminal of the gate 35, the output side of the oscillator 36 is connected to the other input terminal of the gate 35, and the output of the gate 35 is
7, and further connected through a DC blocking capacitor 38 to a primary winding 41 of a pulse transformer 39. Secondary windings 42 and 43 of the pulse transformer 39 are connected between the control input electrodes of the switching elements 21 and 22 and the common electrode, respectively. Connected. The secondary windings 42 and 43 generate pulses of opposite polarities. The power supply unit 44 is connected to the connection point 32,
Starting level detector 33, oscillator 36, buffer 37
Operation power is supplied to such devices. The switching control signal generator 45 including the detector 33, the gate 35, the oscillator 36, the buffer 37, and the power supply 44 is configured as an IC. A tertiary winding 46 is provided on the transformer 23,
One end of the next winding 46 is connected to the connection point 32 through the rectifying diode 47, and the other end is connected to the output terminal 17 of the rectifier 15.

The commercial AC power is full-wave rectified by the rectifier 15, and the rectified output charges the capacitors 18 and 19, and starts the starting capacitor 31 through the resistor 29.
Charge. When the charging voltage of the starting capacitor 31 becomes equal to or higher than a predetermined level, a predetermined power supply voltage V _{CC is supplied} from the power supply unit 44.
Is output, and when the voltage of the starting capacitor 31 exceeds the reference value of the power supply 34, that is, the starting level, the gate 35 opens,
The oscillation output of the oscillator 36 is supplied to the pulse transformer 39, and the switching element 21 is turned on at the rise of the input square wave, and the switching element 22 is turned on at the fall, that is, the switching elements 21 and 22 are alternately turned on and off. Under the control, a current flows alternately in the reverse direction through the primary winding 24, the voltage is boosted to the secondary winding 25, and high-frequency power is output. The high-frequency power induced in the tertiary winding 46 is rectified by the diode 47 and charged in the starting capacitor 31. Once started, the switching control signal generator 45 operates with the power from the tertiary winding 46.

As described above, the switching control signal generator 4
5 is provided independently of the inverter 48 including the switching elements 21 and 22 and the transformer 23, so that the switching elements 21 and 22 can be stably turned on and off at a set frequency regardless of load fluctuations and input voltage fluctuations. Can be. When the tertiary winding 46 is provided to obtain the power of the power supply unit 44, a dedicated power transformer for obtaining the operation power of the switching control signal generation unit 45 is not required.

[0008]

When the AC switch 13 is turned on and off, for example, as shown in FIG. 6A, the commercial AC power input between the input terminals 11 and 12 also turns on and off the switch 13 as shown in FIG. 6B. As shown in FIG. 6C, the voltage of the starting capacitor 31 gradually increases with a time constant determined by the resistor 29 and the capacitor 31 during the ON period, and gradually discharges during the OFF period. Therefore, if the ON period is as short as t ₁ to t ₂ , the voltage of the starting capacitor 31 does not increase to the starting level E ₂ , and the ON period t ₁ to t ₂ does not rise.
The switching control signal at t ₂ is not generated, the voltage of the starting capacitor 31 becomes higher than the operation level E _C, made from that point t ₃ to the switching control signal as shown in FIG. 6D is generated, FIG from the transformer 23 High frequency power is output as shown in 6E.

The time Ts from when the switch 13 is turned on to when the switching control signal is generated is relatively long, for example, about 0.1 to 1.0. Sign light 2
If the light 8 is turned on only when necessary, this lighting delay is not a problem. However, for commercial AC power as shown in FIG.
As shown in FIG. 6G, the AC switch 13 is turned on during a section of a half cycle or less of the commercial AC power, the length of the ON section is controlled, and the commercial AC power input to the input terminals 11 and 12 is as shown in FIG. 6I, the output of the ON rectifier 15 becomes as shown in FIG. 6I, and an inverter output (high-frequency power) having this waveform as an envelope is obtained as shown in FIG. 6J. Even if the brightness is changed as shown in FIG. 6K, that is, the dimming control is performed, if the state where the OFF section of the AC switch 13 is long is repeated many times, the charging of the starting capacitor 31 is performed as described above. Because of the low speed, the voltage of the starting capacitor 31 becomes equal to or lower than the starting level Ec, and the high-frequency power is not output during the ON period of the AC switch 13, so that desired dimming control cannot be performed.

[0010] Similarly, high-speed blinking control for 0.1 second or less cannot be performed. The resistance value of the resistor 29 is usually 50k
Although it is about Ω, it is conceivable that the charging speed of the starting capacitor 31 is increased by reducing this to about several tens of Ω. However, in this case, the power loss in the resistor 29 becomes very large, which is not practical.

[0011]

According to the first aspect of the present invention, a period during which the voltage during the rectified output is smaller than a predetermined value is detected by the period detection means, and the period detection output inserts the voltage into the charging path to the starting capacitor. The turned on switch is controlled to be turned on. According to the second aspect of the present invention, in the first aspect of the present invention, the charging of the starting capacitor is completed during a small voltage period during the rectified output, and the charging up to the starting voltage is completed before the high frequency output becomes the discharge starting voltage of the sign lamp. Is done.

According to the third aspect of the present invention, the variable impedance means is inserted in series into the charging path of the starting capacitor,
The impedance of the variable impedance means is small when the voltage during the rectified output is small, and is large when the voltage is large. According to the fourth aspect of the present invention, the power supply unit for the switching control generation unit is operated by the commercial AC power branched by the branching unit upstream of the rectifier.

[0013]

FIG. 1 shows an embodiment of the first aspect of the present invention, in which parts corresponding to those in FIG. 5 are denoted by the same reference numerals. In this embodiment, an FET switch 51 is inserted in series in the charging path from the rectifying output terminal 16 on the positive side to the starting capacitor 31, and the conventional charging resistor 29 is omitted, but the rush current is limited as necessary. A current limiting resistor 52 of about 10Ω is inserted in series with the switch 51. Rectified output terminal 1
There is provided a period detecting means 53 for detecting a period of a predetermined voltage or less during the rectified output between the steps 6 and 17. For example, rectification output terminal 1
A voltage-dividing resistor circuit 54 is connected between 6 and 17, and a divided voltage output of the voltage-dividing resistor circuit 54 is supplied to a Schmitt gate 55,
The collector and the emitter of the transistor 56 are the switch 51.
Are connected to the control electrode and the rectification output terminal 17, respectively, the output side of the Schmitt gate 55 is connected to the base, and the collector of the transistor 56 is connected to the connection point of the switch 51 and the current limiting resistor 52 through the resistor 57. Further, a bleeder resistor 58 of about 100 kΩ for driving the Schmitt gate 55 is connected in parallel with the switch 51. The trigger level Et of the Schmitt gate 55 is selected to be higher than the reference voltage (start level) Ec of the start level detector 53 and lower than the allowable power supply voltage of the IC constituting the signal generator 45. For example, Ec = 16V, IC allowable voltage 3
Et = 24V at 1V.

In this configuration, the AC switch 13 is
When the on / off control is performed as indicated by Aa, the rectification output terminal 1
The rectified output shown in FIG. 2Ab is obtained between 6 and 17, and while the voltage in the rectified output is equal to or lower than the trigger level Et, FIG.
2, the output of the Schmitt gate 55 is at a low level, the transistor 56 is off, the voltage shown in FIG. 2Ad is applied to the control electrode (gate) of the switch 51, and the switch 51 is turned on as shown in FIG. 2Ae. While the switch 51 is on, charging of the starting capacitor 31 is rapidly performed. That is, the voltage of the starting capacitor 31 immediately becomes a value slightly larger than the starting level Ec. When the voltage of the rectified output exceeds the trigger level Et, the output of the Schmitt gate 55 goes high as shown in FIG. 2Ac, which turns on the transistor 56 and the control voltage of the switch 51 becomes zero as shown in FIG. 2Ad. And the switch 51 is turned off as shown in FIG. 2Ae.

To operate as described above, the AC switch 1
3 is turned on, the starting capacitor 31 is switched to the starting level Ec near the zero level during the first half cycle of the commercial AC power.
As described above, the inverter 48 operates immediately. The voltage of the starting capacitor 31 is in a state as shown in FIG. 2Af, and the high-frequency power is turned on and off by turning on and off the AC switch 13 as shown in FIG. 2Ag.

In the dimming control, the flow angle is usually controlled, and the phase angle from the zero level of the rectified output is controlled. Therefore, the brightness control faithfully responding to the dimming control by such a method is performed. Done. In addition, the flashing control at a high speed such as 0.1 second will operate correctly. As the period detecting means 53, as shown in FIG. 1, a current detecting resistor 59 is inserted in the rectified output current path of the rectifier 15, and when the voltage drop in the current detecting resistor 59 becomes a predetermined value or more, the transistor 56 is turned on. It may be configured to be turned on.

The control of the switch 51 is added to the above conditions,
Before the sign lamp 28 reaches the discharge starting voltage, the starting level E
The starting capacitor 31 is charged up to c.
That is, for the rectified output as shown in FIG. 2Ba, the output high-frequency power becomes as shown in FIG. 2Bb, and at this time, the load current flowing through the sign lamp 28 becomes as shown in FIG. 2Bc. That is, when the amplitude of the high frequency power amplitude of the discharge start voltage becomes a V _S sign lamp 28 is discharged RF power sign lamp 28 in FIG 2Bb is final discharge voltage V _E of the sign lamps 28,
The sign light 28 goes out. In other words, as shown in FIG. 2Bc, the discharge starting voltage V _S starts from the time when the amplitude of the high frequency power is zero.
It is sufficient that the charging voltage of the starting capacitor 31 exceeds the starting level Ec during the interval Ts until the time becomes:
In the embodiment of the present invention, the level of the trigger voltage Et or the resistance value of the current limiting resistor 52 is selected and the starting capacitor 31 is selected.
Immediately before the discharge margin period Ts, the trigger voltage Et
To be For example, it is known that a neon tube discharges when an applied voltage with respect to a standard length tube becomes 1.5 kV. Therefore, the output of the transformer 23 is 6k
V, 9 kV, 12 kV, 15 kV, etc.
Further, the discharge margin period Ts is determined by the number of the sign lamps 28 connected between the output terminals 26 and 27, and the resistance value of the resistor 52, or Select the trigger voltage Et.

FIG. 3A shows a main part of an embodiment of the third aspect of the present invention. Variable impedance means 61 is inserted between the positive side rectified output terminal 16 and the starting capacitor 31 in the charging current path. In this example, the FET 62 is connected between the output terminal 16 and the starting capacitor 31, and the gate of the FET 62,
A resistor 63 is connected between the drain and a Zener diode 64 between the gate of the FET 62 and the rectified output terminal 17.
Is connected.

According to this configuration, the rectification output terminals 16, 17
When the voltage is low, the resistance (impedance) between the source and the drain of the FET 62 is small, and the starting capacitor is charged rapidly. Rectified output terminals 16, 17
When the voltage between them becomes large, the Zener diode 64 conducts, and both ends of the Zener diode 64 become the Zener voltage, and the starting capacitor 31
The resistance (impedance) between the source and the drain of the FET 61 increases so that the voltage of the FET 61 becomes a constant voltage. That is, the charging of the starting capacitor 31 is delayed. As described above, during the period when the voltage of the rectified output is small, the resistance value of the FET 62 becomes small, and rapid charging is performed with low loss. During the period when the voltage of the rectified output is large, the resistance value of the FET 62 becomes large and charging is performed gradually.

FIG. 3B shows a main part of another embodiment of the second aspect of the present invention, and portions corresponding to those in FIG. 3A are denoted by the same reference numerals. In this case, a resistor 65 is inserted between the FET 62 and the starting capacitor 31, and the Zener diode 64 is connected to the FE
It is connected between the gate of T62 and the connection point of the starting capacitor 31 and the resistor 65. Also in this case, the rectification output terminal 1
6 and 17, the resistance between the source and the drain of the FET 62 is small while the output rectified voltage is small.
When the voltage between the FETs 17 increases, the Zener diode 64 becomes conductive, the resistance value between the source and the drain of the FET 62 increases so that the gate and the starting capacitor of the FET 62 are maintained at the Zener voltage, and the starting capacitor 31 is charged. Is constant current charging.

FIG. 4 shows an embodiment of the fourth aspect of the present invention, in which parts corresponding to those in FIG. 1 are denoted by the same reference numerals. Rectifier 1
5, inverters 72 ₁ to 72 _N including an inverter unit 48 and the control unit 71 is provided, the control unit 71 consists of a switching control signal generator 45 and the pulse transformer 39 in FIG. 1, each of the inverters 72 ₁ to 72 _N Input terminal 11,
12 is connected to a commercial AC power source 14 through the AC switch 13 ₁ to 13 _N, respectively. Each of the inverters 72 _{1 to} 7
A power supply unit 73 is branched and connected to the commercial AC power supply 14 before 2 _N , especially before AC switches 13 _{1 to} 13 _N. The power supply terminal 73 is a rectifier circuit 7 for rectifying the output of the transistor 43.
5 and this rectified output is supplied to inverters 72 _{1 to} 72 _N
Are supplied to each of the control units 71 as operating power.

According to this arrangement, when the respective control unit 72 commercial AC power is inputted, without delay, also dimming the AC switch 13 ₁ to 13 _N, regardless of the on-off based on the off controller The operating power is always supplied, and the desired dimming operation and high-speed blinking control can be performed. In addition, the inverters 71 _{1 to} 71 _N do not require a quick charging circuit for the tertiary winding 46, the diode 47, and the starting capacitor 31. 1 and 3, the tertiary winding 46 may be omitted.

[0023]

According to any one of the first to fourth aspects of the present invention, the dimming by the distribution angle control and the fast blinking control can be performed without losing the stability of the frequency and the stability of the control. Based on the improvement of the starting characteristics, the inverter can be started from a relatively low voltage, a wide control range of the dimming control can be secured, and the loss in the charging circuit can be greatly reduced.

According to the first to third aspects of the present invention, only two power supply wires are required, and the workability is excellent. According to the first and second aspects of the present invention, the loss of the charging circuit can be remarkably improved. According to the fourth aspect of the present invention, the number of control power supply wires is increased, but a circuit for improving the start-up and a tertiary winding are not required, and the internal circuit of the inverter is simplified, and the loss of the internal circuit can be reduced.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of the invention of claim 1;

FIG. 2A is a diagram showing an example of waveforms at various parts during the operation of the embodiment of FIG. 1, and FIG. 2B is a diagram for explaining a charging margin period in the embodiment of the second aspect of the present invention.

FIG. 3 is a connection diagram showing a main part of an embodiment of the invention according to claim 3;

FIG. 4 is a block diagram showing an embodiment of the invention of claim 4;

FIG. 5 is a diagram showing a conventional separately-excited inverter type sign light power supply.

6A to 6E are diagrams illustrating waveform examples of respective units in an operation state of the power supply in FIG. 4, and F to K are diagrams illustrating exemplary waveforms of respective units in a dimming operation by flow angle control.

Claims (4)

[Claims] 1. A commercial AC power is rectified by a rectifier, a starting capacitor is charged by the rectified output, an operating power is obtained from a charge of the starting capacitor, a switching control signal is generated from a switching control signal generator, and a switching control signal is generated. A control signal controls the inverter to which the rectified output is supplied, obtains boosted high-frequency power from the inverter, and turns on the sine lamp with the high-frequency power. And a switch inserted in series with the charging path for the starting capacitor and turned on by the period detection output. Power supply for separately excited inverter type sign light. 2. The constant of each part is selected so that the charging of the starting capacitor is performed in a period before the voltage from the zero voltage in the rectified output to the start of discharging of the sign lamp. The power supply for a separately-excited inverter sign light according to claim 1. 3. A rectifier rectifies commercial AC power, charges a starting capacitor with the rectified output, obtains operating power from the electric charge of the starting capacitor, generates a switching control signal from a switching control signal generator, and performs the switching. A control signal controls the inverter to which the rectified output is supplied, obtains boosted high-frequency power from the inverter, and turns on the sign lamp by using the high-frequency power. And a variable impedance means for providing a high impedance during a period when the voltage during the rectified output is low and a high impedance during a period when the voltage is high. Power supply for lights. 4. A commercial AC power is rectified by a rectifier, and the rectified output is converted to a high-voltage high-frequency power by a separately-excited inverter.
In the sign lamp power supply for lighting the sign lamp with the high-voltage high-frequency power, the power supply unit that branches and inputs the commercial AC power in a stage preceding the rectifier and generates operating power of a switching control signal generation unit of the separately excited inverter. A power supply for a separately-excited inverter type sign light, which is provided.