KR20100029590A - Arc protection apparatus for inverter - Google Patents

Abstract

PURPOSE: An arc protection apparatus for an inverter is provided to prevent damage to an output end part of and inverter due to overvoltage by stopping the inverter through outputting arc protect signal when output current at a secondary side of a transformer is abnormal. CONSTITUTION: An arc protection circuit(100) outputs an arc protection signal according to an abnormal current of secondary side output current of the transformer. A controller stops the operation of the inverter according to the arc protection signal from the arc protection circuit. A first detector(110) receives a secondary side output current of a transformer and outputs a detection voltage corresponding to the abnormal current. A second detection unit(120) outputs a switching control signal when a detection voltage outputted from the first detector is higher than the detection voltage.

Description

Arc Protection Apparatus for Inverter

Embodiments relate to an arc protection device of an inverter.

In general, the liquid crystal display (hereinafter referred to as "LCD") is a trend that the application range is gradually increasing due to the characteristics such as light weight, thin, low power consumption driving. According to this trend, LCD is applied to office automation equipment, audio / video equipment and the like. On the other hand, the LCD displays the image by adjusting the transmission amount of the light beam according to the image signal applied to the plurality of control switches arranged in a matrix form.

In general, since LCDs are light-receiving elements that do not emit light by themselves, a backlight having a large transmittance is provided on the rear side of the liquid crystal panel so that the image displayed on the LCD can be clearly seen with uniform brightness.

Cold Cathode Fluorescent Lamps (CCFLs) are commonly used as LCD backlights.

In order to drive the LCD backlight, an apparatus called an inverter is required, and the inverter drives the LCD backlight by converting a DC power into a high voltage AC power and applying the same to the LCD backlight.

In the inverter for LCD backlight, the inverter controller controls the switching operation of the switching unit of the master board and the switching unit of the slave board, respectively, and each switching unit input voltage of the transformer of the master board and the transformer of the slave board. Each transformer outputs an AC voltage boosted by the turns ratio.

The AC voltage output from the transformer is applied to the input terminal of the lamp through the connector of the master board and the connector of the slave board to drive the lamp.

However, since the high voltage is output to the secondary windings of the transformers of the inverter, when the connection of the connector is unstable, sparks are generated due to arc discharge, thereby causing a risk of fire.

The arc protection device of the inverter according to the embodiment can prevent the arc discharge generated when the connector connection of the inverter is unstable and the resulting fire.

The arc protection device of the inverter according to the embodiment includes a transformer provided with a connector on the secondary side, the arc protection circuit for outputting the arc protection signal according to the abnormal current of the secondary output current of the transformer, and the arc output from the arc protection circuit And a controller for stopping the operation of the inverter according to the protection signal.

The arc protection device of the inverter according to the embodiment prevents the arc discharge due to the unstable connection of the connector and the resulting fire, and further has the effect of preventing damage to the output-side components of the inverter due to overvoltage.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a schematic circuit diagram of an arc protection device of an inverter according to an embodiment of the present invention. An arc protection device of an inverter according to an embodiment of the present invention includes a transformer T1 of a master board, a transformer T2 of a slave board, an inverter controller U1, and an arc protection circuit 100.

The secondary windings W1 and W2 of the transformer T1 and the transformer T2 are connected with diodes D1 and D2, a plurality of resistors R1 to R10, IS_1 terminals, and IM_1 terminals.

The inverter control unit U1 has a TIMER stage (pin 15), an OVPT stage (pin 16) and a VREF stage (pin 21) connected to the arc protection circuit 100, and from the arc protection circuit 100 to the TIMER stage. When the arc protection signal is input is configured to turn off the output of the inverter.

As shown in FIG. 2, the arc protection circuit 100 includes a first detector 110, a second detector 120, and an arc protection signal output unit 130.

The first detector 110 includes a capacitor C10 connected in series with an IS_1 terminal, a diode D10 having an anode connected to the capacitor C10, a cathode connected to the second detector 120, and one end of a capacitor C10. ) And a resistor R10 connected between the diode D10 and the other end connected to the ground terminal.

In addition, the first detector 110 includes a capacitor C2O connected in series to the IM_1 terminal, a diode D20 connected to the capacitor C20 and an anode connected to the second detector 120, and one end of the capacitor C2O. The resistor R20 is connected between the C20 and the diode D20 and the other end is connected to the ground terminal.

One end of the second detector 120 is connected to the diode D10 and the diode D20 of the first detector 110, and one end is connected to the other end of the resistor R30, and the other end is grounded. And a capacitor C30 connected to one end of the resistor R30 and one end of the resistor R40 and the other end connected to the ground terminal.

In addition, the second detector 120 may include: a switching element Q1 having a gate terminal commonly connected to the other end of the resistor R30, one end of the resistor R40, and one end of the capacitor C30, and a source end connected to the ground terminal; The anode includes a diode D30 connected to the OVPT end of the inverter control unit U1 and a cathode connected to the drain end of the switching element Q1.

In detail, the switching element Q1 may be a MOSFET.

One end of the arc protection signal output unit 130 may include a resistor R50 commonly connected to the cathode of the diode D30 of the second detector 120 and the drain terminal of the switching element Q1, and one end of the resistor R50. A resistor R60 connected to the other end and connected to the VREF end of the inverter control unit U1 is included.

In addition, the arc protection signal output unit 130 has a base terminal connected to the other end of the resistor R50 and one end of the resistor R60 in common, an emitter terminal connected to the VREF terminal of the inverter controller U1, and a collector terminal connected to the resistor ( R70 includes a switching element Q2 connected to the TIMER terminal of the inverter control unit U1.

In detail, the switching element Q2 may be a transistor.

With reference to the accompanying drawings will now be described the effect of the embodiment of the present invention configured as described above.

The abnormal current among the secondary output currents of the transformer T1 and the transformer T2 is detected by the capacitor C10 and the capacitor C20 of the first detector 110, respectively.

When the transformer T1 and the secondary connector (not shown) of the transformer T2 are stably connected and no arc occurs, an abnormal current occurs in the secondary output current of the transformer T1 and the transformer T2. As a result, a voltage (approximately 0 volts) or less is applied to the gate terminal of the switching element Q1 of the second detection unit 120 to operate the switching element Q1, so that the switching element Q1 operates. It doesn't work.

If the transformer T1 and the secondary connector or the secondary connector of the transformer T2 are unstablely connected, the arc of the secondary output of the transformer T1 or the secondary output current of the transformer T2 may cause a fluctuation of more than a predetermined value. Is generated, a voltage (approximately 2 to 5 volts depending on the connection state of the connector) of the voltage higher than the voltage for operating the switching element Q1 is applied to the gate terminal of the switching element Q1, so that the switching element Q1 is turned on. do.

When the switching element Q1 is turned on, the switching element Q2 of the arc protection signal output unit 130 is turned on so that the VREF terminal voltage (for example, about 5.5 volts) of the inverter control unit U1 is the arc control signal as the arc control signal. It is applied to the TIMER stage of (U1).

The inverter control unit U1 immediately turns off the output of the inverter as the arc protection signal is input to the TIMER stage, thereby preventing the arc discharge caused by the unstable connection of the transformer T1 or the secondary connector of the transformer T2 and the resulting fire. In addition to preventing the damage, the output component of the inverter is additionally prevented from being damaged by overvoltage.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

1 is a schematic circuit diagram of an arc protection device of an inverter according to an embodiment of the present invention.

2 is a detailed circuit diagram of the arc protection circuit shown in FIG.

<Description of the code used in the main part of the drawing>

T1, T2: Transformer U1: Inverter Control Unit

100: arc protection circuit 110: first detection unit

120: second detection unit 130: arc protection signal output unit

Claims (6)

In the inverter comprising a transformer provided with a connector on the secondary side, An arc protection circuit for outputting an arc protection signal according to an abnormal current among secondary output currents of the transformer; And And a control unit which stops the operation of the inverter in response to the arc protection signal output from the arc protection circuit. The method of claim 1, The arc protection circuit receives a secondary output current of the transformer and outputs a detection voltage having a level corresponding to the abnormal current, and a switching control signal when the detection voltage output from the first detection unit is equal to or higher than a set level. And an arc protection signal output unit configured to generate and output the arc protection signal by switching according to a switching control signal output from the second detection unit. The method of claim 2, The first detector includes a capacitor connected in series to one end of the secondary winding of the transformer, a diode connected at one end to the capacitor, and at the other end connected to the second detector, and one end connected between the capacitor and the diode and the other end. Arc protection of the inverter, which includes a resistor connected to this ground terminal. The method of claim 2, And the second detector includes a switching element that operates when the detected voltage output from the first detector is greater than or equal to a set level to output the switching control signal. The method of claim 2, And the arc protection signal output unit includes a switching element configured to switch according to the switching control signal output from the second detection unit to generate and output the arc protection signal. The method according to any one of claims 2 to 5, The transformer is provided in plural, and the first detection unit is provided in plural numbers corresponding to the plurality of transformers to receive the secondary output currents of the plurality of transformers, respectively, and output a detection voltage having a level corresponding to the abnormal current, respectively. And the second detector is operated by receiving respective detection voltages output from each of the plurality of first detectors.

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