KR20100022764A - Analog synchronize circuit of inverter - Google Patents

Abstract

PURPOSE: An analog synchronization circuit of an inverter is provided to accurately control luminance by synchronizing a triangular wave with a square wave. CONSTITUTION: An inverter comprises a synchronous circuit(30). The synchronous circuit is installed between a PWM output terminal of a reference frequency supply unit(10) and a triangular wave output power terminal of an inverter drive unit(20). The synchronous circuit synchronizes the square wave cycle with the period of the triangular wave. The synchronous circuit periodically changes the PWM signal to a high signal. The synchronous circuit discharges the triangular wave output power terminal. The inverter drive unit controls the luminance of the inverter. The synchronous circuit comprises a capacitor and a switching element.

Description

Inverter Analog Synchronization Circuit {ANALOG SYNCHRONIZE CIRCUIT OF INVERTER}

The present invention relates to an inverter analog synchronization circuit.

In general, an inverter refers to a DC / AC converter that converts a DC power source into an AC power source and generates a high voltage using a transformer to drive a load.

Among these inverters, a typical pulse width modulated inverter uses a pulse width modulated signal output from an inverter controller IC to turn on / off the FET, and accordingly, the amount of current supplied to the lamp by the transformer is adjusted to adjust the brightness of the lamp. do.

As shown in FIG. 1, the inverter driving device outputs a HIGH signal when the input VBR is greater than or equal to a preset reference value, and when the input VBR is less than or equal to the preset value, turns on the DUTY corresponding to the preset reference value according to the input value. Reference frequency generating means (1) for outputting an / OFF signal; And an inverter control means (2) for receiving the signal output from the reference frequency generating means (1) to adjust the brightness of the inverter and supply it to the load stage.

Here, VBR refers to a voltage for adjusting the brightness of the inverter, and DUTY refers to a ratio of on / off times generated during one period.

When the VBR for adjusting the brightness of the inverter is input in such a conventional inverter driving apparatus, the reference frequency generating means determines whether the input value is greater than or equal to a preset reference value, and outputs a HIGH signal if the reference value is greater than or equal to the reference value. If the value is less than the reference value, the ON / OFF signal is output to the duty corresponding to the preset reference value according to the input value.

When the output signal is inputted to the inverter control means, the inverter control means converts the input signal into an AC waveform, and outputs the electric field in the load by supplying the signal to each of the loads after the transformer (not shown) boosts. To generate light.

In more detail, when a square wave PWM signal is applied to a SYNC PWM stage from a timing controller (not shown), a triangular wave is charged / discharged through an RC circuit and a comparator (-) stage of the reference frequency generating means (1). Is inputted to the comparator (+) terminal of the reference frequency generating means 1 through the register via the VBR terminal, the voltage range of the luminance control voltage VBR ( 0 ~ 3.3V), the duty of the pulse width modulated signal is adjusted between 40 ~ 100% and output.

At this time, the frequency of the pulse width modulated signal is determined by the time constant circuit of the resistor and the capacitor connected to the reference frequency generating means 1 or the inverter driving means 2.

However, in the conventional inverter drive circuit as described above, the frequency of the pulse width modulated signal output from the reference frequency generating means 1 is determined by the time constant circuit of the resistor and capacitor connected to the reference frequency generating means 1, And an error of about 7% (about 13 Hz) occurs when the reference frequency of the pulse width modulated signal is 180 Hz due to the variation in the characteristic values of the capacitor.

In addition, since the triangular wave is made and applied outside the reference frequency generating means 1, there is a problem that the triangular wave itself is uneven.

 Inverter analog synchronizing circuit according to an embodiment of the present invention obtains a triangular wave that is exactly synchronized with the square wave provided by the reference frequency providing means from the inverter driving means, so that the correct luminance is adjusted.

The present invention converts the PWM signal provided from the reference frequency providing means into a periodic high signal of a predetermined level and provides it to the triangular wave output stage of the inverter driving means to force the discharge of the triangular wave output stage, thereby providing the square wave period and the triangular wave output stage of the reference frequency providing means. And a synchronizing circuit for synchronizing the period of the triangular wave output from the PWM output terminal of the reference frequency providing means and the triangular wave output terminal of the inverter driving means.

The present invention obtains a triangular wave from the inverter driving means which is precisely synchronized with the square wave provided by the reference frequency providing means, so that accurate luminance adjustment can be made.

2 is a block diagram briefly illustrating a configuration according to an embodiment of the present invention, and FIG. 3 is more specifically a configuration according to an embodiment of the present invention. 4 is a waveform diagram of the output signal of the ONE PULSE signal on the synchronization circuit side of the present invention, and FIG. 5 is a waveform diagram showing a triangular wave output state synchronized to a reference square wave.

The present invention will be described below with reference to the accompanying drawings presented as above.

First, as shown in FIG. 2, the present invention converts the PWM signal provided from the reference frequency providing means 10 into a periodic high signal of a predetermined level and outputs a triangular wave output terminal BCT_A of the inverter driving means 20. By providing to the forcibly discharged triangular wave output terminal (BCT_A), the reference frequency providing means for synchronizing circuit 30 for synchronizing the period of the triangular wave output from the triangular wave output terminal (BCT_A) with the square wave period of the reference frequency providing means (10) It is characterized in that it is provided between the PWM output terminal (PWM) of (10) and the triangular wave output terminal (BCT_A) of the inverter driving means (20).

Referring to the configuration of the present invention in more detail, as shown in FIG.

Here, the reference frequency providing means 10 may be a timing controller for outputting a constant square wave.

In this case, the reference frequency providing means 10 may be a timing controller IC that outputs SYNC_PWM (180 Hz Duty 50%, 3.3V).

On the other hand, the inverter driving means 20 of the present invention may be an inverter controller for receiving a signal output from the reference frequency generating means 10 to adjust the brightness of the inverter to supply to the load stage.

On the other hand, the synchronization circuit 30 of the present invention is a capacitor 1 (C1) connected to the PWM output terminal (PWM) of the reference frequency providing means 10; And a switching device Q1 operating on / off according to the charge / discharge cycle of the capacitor 1 (C1).

The switching element Q1 may be a MOS-FET.

In addition, one side of the capacitor 1 (C1) may be connected to the PWM output terminal (PWM) of the reference frequency providing means 10, the other side may be connected to the gate terminal of the switching element (Q1).

In addition, the switching element Q1 has a gate terminal connected to the capacitor 1 (C1), a source terminal grounded through the capacitor 3 (C3), and the drain terminal of the switching element Q1 to the triangular wave output terminal BCT_A of the inverter driving means 20. Can be connected.

Referring to the operation of the present invention configured as described above are as follows.

First, a constant square wave, that is, SYNC_PWM (180 Hz Duty 50%, 3.3 V) is provided from the timing controller IC, which is the reference frequency providing means 10.

When SYNC_PWM (180Hz Duty 50%, 3.3V) is applied from the reference frequency providing means 10 to the capacitor 1 (C1) constituting the synchronous circuit 30, the capacitor 1 (C1) is attached through charge and discharge. A vertical ONE PULSE shown in FIG. 4 is output.

The ONE PULSE output through the capacitor 1 (C1) causes the triangular wave to start when Hi (2.2 V), and pulls it down to Lo (0.5 V) so that the triangular wave can start.

As described above, whenever the ONE PULSE is output through the capacitor 1 (C1), the MOS-FET Q1 repeats the turn-on operation, and a signal is output through the turn-on to output the triangular wave output terminal BCT_A of the inverter driving means 20. By directly applying), the triangle wave output terminal BCT_A of the inverter driving means 20 is forcibly discharged.

The period of the triangular wave is determined according to the discharge signal as described above, and the period of the square wave and the triangular wave of the reference frequency providing means 10 is exactly the same as shown in FIG. 5.

According to the present invention as described above, the triangular wave that is precisely synchronized with the square wave provided by the reference frequency providing means 10 is outputted from the inverter driving means 20 with a constant period while maintaining a constant level, thereby making accurate luminance adjustment. do.

While the invention has been described and illustrated in connection with a preferred embodiment for illustrating the principles of the invention, the invention is not limited to the configuration and operation as such is shown and described.

Rather, it will be apparent to those skilled in the art that many changes and modifications to the present invention are possible without departing from the spirit and scope of the appended claims.

Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is a circuit diagram showing a configuration according to a synchronous method of a conventional inverter.

2 is a block diagram schematically showing a configuration according to an embodiment of the present invention.

3 is a circuit diagram showing in more detail the configuration according to an embodiment of the present invention.

Figure 4 is a waveform diagram of the output signal of the ONE PULSE of the synchronization circuit side of the present invention.

5 is a waveform diagram showing a triangular wave output state synchronized to a reference square wave;

<Description of the symbols for the main parts of the drawings>

10: reference frequency providing means 20: inverter driving means

30: synchronous circuit

Claims (4)

By converting the PWM signal provided by the reference frequency providing means into a periodic high signal of a predetermined level and providing it to the triangular wave output terminal of the inverter driving means to force the discharge of the triangular wave output stage, which is output from the square wave period and the triangular wave output stage of the reference frequency providing means. An inverter analog synchronizing circuit comprising a synchronizing circuit for synchronizing a period of a triangular wave between a PWM output terminal of a reference frequency providing means and a triangular wave output terminal of an inverter driving means. The method of claim 1, And said reference frequency providing means is a timing controller IC for outputting SYNC_PWM 180Hz Duty 50%, 3.3V. The method of claim 2, The inverter driving means is an inverter analog synchronization circuit characterized in that the inverter controller for receiving the signal output from the reference frequency providing means to adjust the brightness of the inverter to supply to the load stage. The method of claim 2, The synchronization circuit includes a capacitor 1 connected to the PWM output terminal of the reference frequency providing means; And Inverter analog synchronization circuit, characterized in that it comprises a switching element to operate on / off in accordance with the charge / discharge period of the capacitor 1.

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