JPH06168792A - Inverter lighting circuit - Google Patents

Abstract

PURPOSE:To enable a general purpose IC to be used, and eliminate the necessity of adjustment by using a square wave resulting from the division of an output signal from the oscillation section made of a crystal oscillator, a NOT circuit and a resistor, into a desired frequency as a lighting control signal for a fluorescent lamp. CONSTITUTION:A control signal from a lighting control circuit 4 is outputted to the gate of a switching element Q1 for switching DC power from a DC power circuit 6 to rectify a commercial power supply 5. The circuit 4 is constituted of an oscillation section 12 where a crystal oscillator 8 having a desired oscillation frequency, a NOT circuit 1 and a resistor R are connected in parallel, and a counter 18 for outputting a square wave on/off signal resulting from the division of an output signal from the section 12, into a desired frequency. In this case, an upstream counter and a downstream comparator may be used, instead of the counter 18. According to this construction, adjustment for the electrical dispersion of components can be eliminated, as the main section of the circuit 4 comprises a digital circuit. Also, a dedicated LSI is not used. thereby allowing an easy design change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter lighting circuit, and more particularly to an inverter lighting circuit for exciting a discharge lamp such as a fluorescent lamp at a frequency higher than that of a normal commercial AC power source to light the discharge lamp.

[0002]

2. Description of the Related Art Generally, an inverter lighting circuit is more flicker than a conventional lighting circuit driven by a commercial AC power source by lighting a fluorescent lamp with a high frequency power of 40 to 50 kHz, which has a higher frequency than a commercial AC power source. It is low in number, bright, and capable of high-efficiency lighting, and is frequently used.

FIG. 10 shows a typical separately-excited inverter lighting circuit in this type of conventional inverter lighting circuit.

In FIG. 10, when the switch S10 is turned on, the AC power supplied from the external commercial AC power supply 5 is
It is supplied to the DC power supply circuit 6, and is converted into DC having a predetermined voltage by the DC power supply circuit 6. One end of the fluorescent lamp 2 is connected to the high potential output side of the output of the DC power supply circuit 6, and the other end of the fluorescent lamp 2 is connected to one end of the switching element Q1 via the coil L1. The other end of the switching element Q1 is connected to the low potential side of the output of the DC power supply circuit 6.

As the switching element Q1, for example, a field effect transistor may be used. The lighting control circuit 4 is provided at the gate terminal of the switching element Q1.
The output of A is connected. DC power having an appropriate voltage is supplied from the DC power supply circuit 6 to the lighting control circuit 4A.

A coil L2 and a capacitor C2 are connected in parallel between the high potential side of the output of the DC power supply circuit 6 and the connection portion of the switching element Q1 and the coil L1 to form a parallel resonance circuit. When a lighting control signal (for example, a frequency of 40 kHz) having a frequency higher than that of the commercial AC power supply is applied to the gate terminal of the switching element Q1 from the lighting control circuit 4A described above, the switching element Q1 is turned on / off according to the lighting control signal. Then, the DC power supplied to the fluorescent lamp 2 is switched and turned on.

A capacitor C1 is connected in parallel to the fluorescent lamp 2, and the coil L1 and the capacitor C1 form a series resonance circuit. The resonance frequencies of the series resonance circuit formed by the coils L1 and C1 and the parallel resonance circuit formed by the coil L2 and the capacitor C2 are set to approximately match the frequency of the lighting control signal supplied to the switching element Q1. .

The components constituting the lighting control circuit described above include those using an analog circuit and those using a digital circuit. For those using a digital circuit, a dedicated LSI or the like is used. Has been.

[0009]

Among the conventional inverter lighting circuits described above, in the case where an analog circuit is used for the lighting control circuit, there are variations in the circuit components used, and the lighting control circuit is caused by this variation. Since the frequency is different from the desired value, there is a drawback that a long adjustment time is required to correct this variation.

When a dedicated digital circuit is used for the lighting control circuit, when it is desired to perform additional heat start, protection of the inverter lighting circuit from overvoltage or overcurrent, or addition of additional functions such as remote control. L
Since the SI must be redesigned, it has a drawback that it is difficult to easily add or change the above-mentioned additional functions.

An object of the present invention is to provide an inverter lighting circuit that uses a general-purpose digital circuit that can be adjusted as the above lighting control circuit.

[0012]

An inverter lighting circuit of the present invention rectifies external AC power into DC power, which is switched by a switching element controlled by a lighting control signal output from a lighting control circuit. In an inverter lighting circuit for lighting a fluorescent lamp at a high frequency, the lighting control circuit has an oscillation unit configured by connecting a crystal oscillator, a NOT circuit, and a resistor in parallel, and an output from the oscillation unit is predetermined. Square O divided into different frequencies
And a counter that outputs an N / OFF signal as the lighting control signal.

In the inverter lighting circuit of the second aspect of the invention, external AC power is once rectified into DC power, and the DC power is switched by a switching element controlled by a lighting control signal output from the lighting control circuit to cause fluorescence. In the inverter lighting circuit that lights the lamp at high frequency,
The lighting control circuit receives an oscillation unit configured by connecting a crystal unit, a NOT circuit, and a resistor in parallel, a predetermined first load value, and an output of the oscillation unit as input, and the emission unit. A low-order counter that counts the output waves of the above, adds the first load value, outputs the first count signal, outputs a carry signal when a carry occurs, and resets the value when a reset signal is received; The determined second load value and the output of the oscillating unit are input, the output wave of the oscillating unit is counted, the sum of the second load value is output as a second count signal, and the output is An upper counter that resets the value of the second count signal when a reset signal is received by outputting a part of the above as the lighting control signal, and the first and second count signals and a predetermined reference value. Force and to the first sum of the second count value is configured by a comparator for outputting the equal and the reset signal and the reference value.

[0014]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 (A) is a block diagram showing an embodiment of the inverter lighting circuit of the present invention, and FIG. 1 (B) is FIG.
It is a block diagram which shows one Example of a structure of the lighting control circuit used by the inverter lighting circuit of (A), and is FIG.
1 can be used in FIG. 1 (A), respectively.
It is a block diagram which shows the Example of the lighting control circuit different from (B).

FIGS. 6 and 7 are explanatory views showing the input / output relationship of the main part in the embodiment shown in FIG. 3, and FIG. 8 is a load value of the lighting control circuit of FIG. 5 and the lighting control output. It is explanatory drawing which shows an example with respect to the frequency of a signal, and a duty ratio, and FIG. 9 (A) and FIG. 9 (B) is a waveform diagram which shows the example of the output waveform of a lighting control signal.

The inverter lighting circuit shown in FIG. 1A is the same as the inverter lighting circuit shown in FIG. 7 except that the lighting control circuit 4 is used instead of the lighting control circuit 4A of the conventional inverter lighting circuit. First, only the lighting control circuit 4 will be described, and description of other parts will be omitted.

The lighting control circuit 4 of FIG. 2 includes a NOT circuit 1 and
One end is connected to the input end of this NOT circuit 1 and the other end is N
The oscillating unit 1 includes the crystal oscillator 8 connected to the output side of the OT circuit 1 and the resistor R connected in parallel to the crystal oscillator 8.
9 has a duty ratio of 50% obtained by dividing the frequency of the output of the NOT circuit 1 into an input and dividing it into a predetermined frequency.
The counter 18 outputs a square wave having a waveform as shown in (A) as a lighting control signal.

As the crystal oscillator 8, for example, one that oscillates at a frequency of 4.2 MHz is used, and as the counter 18, for example, the input signal is divided into 1/70 and a square wave having a duty ratio of 50% is output. If you set it to
A lighting control signal having a frequency of 60 kHz shown in FIG. 9A can be output.

The input terminals X1 and X2 and the output terminals Y1 and Y2 of the lighting control circuit shown in FIG. 1B respectively correspond to the same input terminal in FIG. 1A.

The duty ratio described above does not have to be 50%.

Further, the lighting control circuit 4 of FIG.
When the same oscillation unit 12 as shown in (B) and the output from the oscillation unit 12 and the first load signal are input and a carry signal is output and a reset signal described later is added, the count value is changed. The lower counter 9 to be reset, the output of the oscillator 12, the second load signal, and the carry signal output from the lower counter 9 are input, and the above-mentioned lighting control signal is output.
The upper counter 10 that resets the count value when a reset signal is applied, and the outputs of the lower counter 9 and the upper counter 10 and the reference value are input, and the sum of the outputs of the lower counter 9 and the upper counter 10 is equal to the reference value. Then, it is composed of a comparator 11 which outputs a reset signal.

In FIG. 2, a low level (ground level) is applied to the input terminals A and B of the lower counter 9, and a high level (+5 volts) is applied to the input terminals C and D.
The least significant digit of the input terminal is A and the most significant digit is D, and the input terminals A to D of the lower counter 9 are input with 1100 in binary notation and C in hexadecimal notation as the first load signal. Has been done. The lower-order counter 9 has a 4-digit output terminal QA to QD in binary notation, and QC is the highest digit and QA is the lowest digit. The lower counter 9 has a terminal C which receives the output of the oscillator 12 in addition to the above-mentioned input terminals A to D.
Oscillator 12 that has LK and is added to terminal CLK
The output waves of the above are counted, and the sum of the counted value and the value of the first load signal applied to the input terminals A to D is output as a count value to the comparator 11 from the terminals QA to QD. When a carry occurs in the counted value, a carry signal is sent from the terminal RCO to the upper counter 10.
Output to. When a reset signal is applied to the terminal LOAD from the comparator 11, the count value is reset to 0.

The high-order counter 10 has terminals A to D as input terminals for the second load signal, the input terminal A being the lowest digit, and the input terminal D being the highest digit. In FIG. 2, the input terminals A to D have the same value as that applied to the input terminals A to D of the lower counter (that is, 1
C) in hexadecimal notation has been added as a second load signal.

The output of the oscillator 12 is applied to the terminal CLK of the upper counter 10, and the carry signal from the lower counter 9 is applied to the terminals ENP and ENT.

Of the output terminals QA to QD of the high-order counter 10, QA outputs the lowest digit and QD outputs the highest digit. The output of the highest digit among these output terminals becomes the output of the lighting control signal, and the outputs from the output terminals QA to QC excluding the output terminal QD are output to the comparator 11. That is, the output in binary notation is applied to the comparator 11 from the output terminals QA to QC.

The upper counter 10 counts the output wave of the oscillating unit 12 and the carry signal from the lower counter 9, and outputs the sum of the count value and the value of the second load signal to the comparator 11. When a reset signal is applied to the terminal LOAD from the comparator 11, the upper counter 10 resets its count value to zero.

The comparator 11 receives the outputs from the low-order counter 9 and the high-order counter 10 for each digit, compares them with a reference value input separately, and when both are equal, a reset signal is sent to the low-order counter 9 and the high-order counter 10.
And output to.

FIG. 8 shows a load value (1) in which the value of the second load signal is the upper digit and the value of the first load signal is the lower digit.
(Hexadecimal notation) and an explanatory diagram showing an example of a frequency and a duty ratio (%) of a lighting control signal output when the load value is added.

As is clear from the above description, the period of the lighting control signal is determined by adding an appropriate reference value for the oscillator 12 having a specific frequency to the comparator,
By giving appropriate values as the first and second load signals, a desired duty ratio can be given to the lighting control signal.

Although the upper and lower counters are used as counters in the embodiment of FIG. 2, instead of these counters, input terminals and output terminals each having twice as many input terminals are provided. Obviously, one counter having an output terminal may be used.

The lighting control circuit 4 shown in FIG. 3 has the same oscillating section 12, a lower counter 9, an upper counter 10 and a comparator 11 as shown in FIG.
Switches S1 to S9 that are turned on only when pressed
The input terminals A1 to A9 are individually connected to the high potential side contacts of the switches S1 to S9, respectively, and an encoder 14 for converting and outputting a code according to a predetermined conversion formula, and an output of the encoder 14 are provided. NAND as input
A gate 16 and a D flip-flop circuit 15 including a plurality of D flip-flops that receive the output of the NAND gate 16 as a clock input and the output of the encoder 14 as an input are provided.

The encoder 14 has output terminals A to D, the least significant digit is A, the most significant digit is D,
Further, it has A1 to A9 as input terminals, the lowest input terminal is A1, and the highest input terminal is A9.

The D flip-flop circuit 15 has a NAN.
It is composed of four D flip-flops for inputting the output of the D gate 16 as a common clock signal, and the input terminal is D1.
~ D4, the output terminals have Q1 to Q4.

In FIG. 3, the D flip-flop 15
Output terminals Q1 and Q2 are connected to the input terminals C and D of the lower counter 9, respectively, and output terminals Q3 and Q4 are connected to the input terminals A and B of the upper counter 10, respectively.

The output terminals Q1 to Q4 are output terminals for outputting the input levels as inverted levels when the clock signal changes from the low level to the high level.

Each of the switches S1 to S9 is turned on when pressed, and the contact on the high potential side, that is, the contact connected to the input terminal of the encoder 14 becomes the ground potential (low level). .

When the switches S1 to S9 are not pressed, the input terminals of the encoder 14 connected to these switches are at high potential.

The encoder 14 is set so as to output 1111 in binary notation as an output when all its inputs are at a high level, that is, a high level signal from all of the output terminals A to D of the encoder 14. Is output.

When any one of the switches S1 to S9 is pressed, the output terminal A of the encoder 14 is pressed.
At least one of D is set to output a low level, that is, 0.

In the example shown in FIG. 6, when the switch S9 is pressed, the value of decimal 9 expressed in binary, that is, 0110 which is the value obtained by subtracting 1001 from 1111 is the output of the encoder 14. When the SN switch (N is an integer) is output from a terminal and the switch is generally pressed, the decimal number N is expressed in binary as 111.
The conversion formula of the encoder 14 is set so that the value subtracted from 1 is output.

In addition, two of the switches S1 to S9 are simultaneously operated.
When more than one is pressed, the encoder 14 is set so as to receive only the input of one switch connected to the higher digit among the input terminals of the encoder 14.

When none of the switches S1 to S9 is pressed, the output of the encoder 14 is 1111 and the output of the NAND gate 16 is at low level "0". At this time, the output of the D flip-flop circuit 15 outputs the value previously output from the encoder 14.

When any one of the switches S1 to S9 is pressed, a low level "0" is output from at least one of the output terminals A to D of the encoder 14 input to the NAND gate 16. "Is output, so NAN
Since the output level of the D gate 16 becomes a high level, at this time, the D flip-flop circuit 15 outputs an inverted version of the output level of the encoder 14 input immediately before.

For example, when the switch S9 is pressed, 0110 is output from each of the output terminals D to A of the encoder 14 as shown in FIG. These signals are applied to the input terminals of the D flip-flop circuit 15, and immediately after that, the output from the NAND gate 16 changes from the low level to the high level, so that the signals are input from the output terminals Q1 to Q4 of the D flip-flop circuit 15. A signal 1001 whose level is inverted is output.

The outputs of the output terminals Q1 and Q2 among them are respectively the input terminals C and D of the lower counter 9 already described.
Added to. In addition, the outputs of the output terminals Q3 and Q4 of the flip-flop circuit 15 respectively correspond to the upper counter 10
Input terminals C and D respectively.

Further, a constant high level signal is applied to the input terminals A and B of the lower counter 9, and similarly, a constant high level signal is also applied to the input terminals C and D of the upper counter 10. Has been added. Therefore, the input of the lower counter 9 is 0111, that is, 7 in hexadecimal notation.

At this time, the input of the upper counter 10 is 1
110, that is, E in hexadecimal notation.

That is, 011 is set as the first load signal.
1 and 1110 as a second load signal are added to the lower counter 9 and the upper counter 10, respectively.

When these load signals are put together, it becomes E7 in hexadecimal notation. Here, by setting the reference value applied to the comparator 11 to an appropriate value, as shown in FIG. 7, when the value input to the counter is E7, the frequency of the lighting control signal output from the upper counter 10 is 6
At 9.9 kHz, the duty ratio can be 41.7%.

Further, for example, when the switch S2 is pressed, the upper and lower counters are set to 16 as shown in FIG.
C and B are entered in decimal notation, respectively.
A lighting control signal having a waveform as shown in (B), a duty ratio of about 60% and a frequency of about 48 kHz is output.

The configuration of the lighting control circuit 4 used in the present invention shown in FIG. 4 is similar to that of the switches S1 to S1 already described in FIG.
Instead of the S9, the NAND gate 16 and the D flip-flop circuit 15, a variable resistor VR having power supplies having appropriate potential levels respectively connected to both ends, the output of the sliding terminal of the variable resistor VR, and this variable resistor VR It is provided with an A-D converter 7 having inputs at both ends of the resistor VR. The output of the upper digit of the output of the A / D converter 7 is connected to the input terminal of the upper counter 10, and the output of the lower digit is connected to the input terminal of the lower counter 9. Other than that, it has the same configuration as the lighting control circuit described in FIG.

Therefore, by changing the sliding terminal of the variable resistor VR to change the level applied to the AD comparator 7, the first load value and the second load value are set to desired values. As a result, the frequency and duty ratio of the lighting control signal, which is the output of the most significant digit on the output side of the high-order counter 10, can be changed.

In the lighting control circuit of FIG. 5, a program of processing operation according to a brightening command and a dimming command applied from the outside is stored in advance, and the first and second load are carried out according to these external commands. It outputs a signal and a reference value to be given to the comparator 11, and the crystal oscillator 8
The microcomputer 17 which is connected to and outputs a predetermined oscillation signal, and the load value given by the first load signal are input, and the above-mentioned oscillation signal which is input separately to this load value is counted and the result is described later. Comparator 11
To a lower counter 9 for outputting a carry signal to an upper counter 10 which will be described later, and a load value given by the second load signal, and adding the above-mentioned oscillation signal separately input to this load value. And counts the result and outputs the result to the comparator 11 and outputs the uppermost digit as a lighting control signal, a preset reference value, and the outputs of the lower counter 9 and the upper counter 10 described above. A comparator which inputs a certain count value and compares it with the above-mentioned reference value, and when the count value becomes equal to the reference value, outputs a reset signal to the lower counter 9 and the upper counter 10, and resets the count values of these counters 9 and 10. 11 and 11.

FIG. 8 shows the load value of the load signal output from the microcomputer 17 and the upper counter 10.
It is explanatory drawing which shows an example of the relationship of the frequency and the duty ratio of the lighting control signal output from.

The load value shown in FIG. 8 is shown in hexadecimal notation. For example, the load value E3 is 11100011 in binary notation and the load value D7 is 11010111 in binary notation.

The lighting control circuit shown in FIG. 5 is supplied with DC power having an appropriate voltage from the DC power supply circuit 6 shown in FIG. 1A through terminals X1 and X2. To be done.

When the switch S10 of FIG. 1 is turned on, the microcomputer 17 and the crystal oscillator 8 output an oscillation signal having a frequency of, for example, 4.19 MHz. This is the operation of the lighting control circuit 4. It is also a clock signal.

This oscillation signal is applied to the lower counter 9 and the upper counter 10. At the same time, the load signal from the microcomputer 17 is also sent to the lower counter 9
Is added to the upper counter 10. Now, it is assumed that the microcomputer 17 outputs D7 which is an intermediate value among the load values shown in FIG. At this time, the load signal corresponding to the lower 7 values among these load values, that is, 0111 in binary notation is 2 as the first load signal.
It is added to the lower counter 9 for each digit of the base number. Further, a load value corresponding to D in hexadecimal notation, which is a higher value among the load values, that is, 1101 in binary notation is added to the upper counter 10 as a second load value for each digit.

The low-order counter 9 and the high-order counter 10 add up counted input oscillation signals to the added first load value or second load value, and output to the comparator 11 as a count value. . The comparator 11 simultaneously receives the count values from the lower counter 9 and the upper counter 10 for each digit, compares them with a preset reference value, and resets when the reference value and the input count value become equal. The signal is output to the lower counter 9 and the upper counter 10 to reset the count value.

The carry signal from the lower counter 9 is input to the upper counter 10. If the reference value given to the comparator 11 in advance is set to an appropriate value, FIG.
When the load value as shown in FIG. 3 is output from the microcomputer 17, the lighting control signal having the corresponding frequency and duty ratio shown in this figure can be output from the upper counter 10.

For example, when the load value D7 is output from the microcomputer 17, as shown in FIG. 8, the frequency is 55.2 KHz and the duty ratio is 53.
The lighting control signal of 9% is output from the high-order counter 10.

Here, every time a brightening command is input to the microcomputer 17 from the outside, the microcomputer 17 outputs the load value shown in FIG. 8 immediately before the brightening command is output. The load values shown in the line below the load value are set to be output one by one, and each time the dimming command is added, the load value output immediately before is set according to FIG. The program stored in the microcomputer 17 is set so that the load value in the line immediately above the line shown in FIG.

By setting the program of the microcomputer 17 in this way, the fluorescent lamp 2 of the inverter lighting circuit shown in FIG. 1A can be dimmed. Further, by changing the program stored in the microcomputer 17, control other than the above dimming operation can be performed.

Although the lower counter 9 and the upper counter 10 are used in the embodiments of FIGS. 2 to 5,
It is obvious that the lower counter 9 and the upper counter 10 may be replaced by one counter having a number of digits twice that of these counters.

In the embodiments of FIGS. 3 to 5, the most significant digit on the output side of the high-order counter is output as the lighting control signal, but any one of the terminals on the output side of the high-order counter is output. Obviously, one output may be used as the lighting control signal.

[0067]

As described above, in the inverter lighting circuit of the present invention, since the main part of the lighting control circuit is composed of a digital circuit, it is not necessary to make adjustments due to electrical variations of parts, and Since it can be configured with general-purpose electronic components without using a dedicated LSI, it is easy to change the design by changing the program stored in the microcomputer or by changing some of the components. Has the effect of being

[Brief description of drawings]

1A is a block diagram showing an embodiment of an inverter lighting circuit of the present invention, and FIG. 1B is a block diagram of FIG.
It is a block diagram which shows an example of the lighting control circuit shown by (A).

FIG. 2 is a block diagram of a lighting control circuit used in the present invention, which is different from that shown in FIG.

FIG. 3 is a block diagram of a lighting control circuit used in the present invention, which is different from those in FIGS. 1B and 2.

FIG. 4 is a block diagram of a lighting control circuit used in the present invention, which is different from the lighting control circuit shown in FIG. 1B and FIGS.

5 is a block diagram of a lighting control circuit used in the present invention, which is different from that shown in FIG. 1B and FIGS.

FIG. 6 is an explanatory diagram showing the relationship between the input / output of the encoder and the input of the counter shown in FIG.

FIG. 7 is an explanatory diagram showing a relationship between the switch shown in FIG. 3 and a lighting control signal.

8 is an explanatory diagram showing a relationship between a load value of the lighting control circuit shown in FIG. 5 and a lighting control signal.

FIG. 9 is a waveform diagram showing a waveform of a lighting control signal.

FIG. 10 is a block diagram showing an example of a conventional inverter lighting circuit of this type.

[Explanation of symbols]

 1 NOT Circuit 2 Fluorescent Lamp 4 Lighting Control Circuit 6 DC Power Supply Circuit 7 A-D Converter 8 Crystal Resonator 9 Lower Counter 10 Upper Counter 11 Comparator 12 Transmitter 14 Encoder 15 D Flip-Flop Circuit 16 NAND Gate 17 Microcomputer 18 Counter

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[Procedure amendment]

[Submission date] December 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

Claims (5)

[Claims] 1. An inverter lighting circuit for rectifying external AC power into DC power and switching the DC power by a switching element controlled by a lighting control signal output from a lighting control circuit to light a fluorescent lamp at a high frequency. The lighting control circuit includes an oscillating unit configured by connecting a crystal oscillator, a NOT circuit, and a resistor in parallel, and a square ON / OFF signal obtained by dividing the output from the oscillating unit into a predetermined frequency. And a counter for outputting the lighting control signal as the lighting control signal. 2. An inverter lighting circuit for rectifying external AC power into DC power, which is switched by a switching element controlled by a lighting control signal output from a lighting control circuit to light a fluorescent lamp at a high frequency. The lighting control circuit receives an oscillation unit configured by connecting a crystal unit, a NOT circuit, and a resistor in parallel, a predetermined first load value, and an output of the oscillation unit as input, and the emission unit. A low-order counter that counts the output waves of the above, adds the first load value, outputs the first count signal, outputs a carry signal when a carry occurs, and resets the value when a reset signal is received; The predetermined second load value and the output of the oscillating unit are input, the output wave of the oscillating unit is counted, and the sum of the second load value is added to the second scale. A high-order counter that resets the value of the second count signal when a reset signal is received and a part of the output is output as the lighting control signal, and the first and second count signals are predetermined. An inverter lighting circuit, comprising: a comparator that outputs the reset signal when the sum of the first and second count values is equal to the reference value with the received reference value as an input. 3. An inverter lighting circuit for rectifying external AC power into DC power and switching the DC power by a switching element controlled by a lighting control signal output from a lighting control circuit to light a fluorescent lamp at a high frequency. The lighting control circuit is connected to the crystal unit and generates and outputs an oscillation signal having a predetermined frequency, and outputs a load signal corresponding to a brightening signal and a dimming signal externally applied. And a microcomputer, which temporarily stores a load value corresponding to the load signal, counts the oscillation signal, adds the count to the load value, outputs the count value, and outputs a part of the output of the count value as the lighting control signal. A counter that resets the count value when a reset signal is input, and a counter that inputs the count value An inverter lighting circuit, comprising: a comparator that outputs a reset signal when the count value and the reference value are equal to each other when compared with a predetermined reference value. 4. An inverter lighting circuit for rectifying external AC power into DC power and switching the DC power by a switching element controlled by a lighting control signal output from a lighting control circuit to light a fluorescent lamp at a high frequency. The lighting control circuit includes a transmitting unit configured by connecting a crystal unit, a NOT circuit, and a resistor in parallel, and turns on only when pressed, and outputs a low-level potential, and otherwise outputs a high-level potential. When the outputs of all the switches are high level and the outputs of all the switches are high level, the outputs of all the switches are high level and low level. The output of at least one output terminal is at a low level when the N-th input in the order of the An encoder for converting the digital amount according to the conversion formula and outputting from a plurality of terminals, a NAND gate for inputting all of the outputs of the encoder to each input terminal, and an output of the NAND gate as a common clock input, A plurality of D flip-flop circuits each receiving one output of the encoder, and ones in which outputs of the plurality of D flip-flop circuits are input as load values, the oscillation waves of the oscillation unit are counted, and the load values are added. Is output as a count signal and a part of the output is output as the lighting control signal, and a counter that resets the value of the count signal when a reset signal is received and the count value and a predetermined reference value are input. And a comparator that outputs the reset signal when the count value and the reference value are equal Inverter lighting circuit, characterized in that it comprises. 5. Instead of the plurality of switch circuits, the encoder, the NAND gate and the D flip-flop circuit, both terminals are connected to the low level and the high level of the DC power supply, and the level of the DC power supply is changed from the sliding terminal. And a variable resistor for outputting the variable resistor, and an A-D converter for connecting the sliding terminal of the variable resistor to an input terminal, converting the variable resistor into a digital value corresponding to the level of the sliding terminal, and outputting the digital value as the load value. The inverter lighting circuit according to claim 4, further comprising: