KR200417242Y1 - Current interception protection circuit - Google Patents

Abstract

The present invention is a ballast for outputting high frequency and high voltage in order to light a discharge lamp of a fluorescent lamp or a backlight unit of a display device, or a protection circuit for blocking output when a human body touches a high voltage output part while an inverter is being driven. Voltage is generated by pull dowm by applying voltage to the backlight unit and one-to-one connection with the transformer part of transformer T1 and transformer T2 which are in frequency phase and operate in reverse phase with each other and the transformer low voltage side of the transformer part. Determining the presence or absence of human body contact and detecting an abnormality by comparing a node portion consisting of a node point N1 and a node point N2 with a reference voltage Vref having a constant voltage and the voltage formed at the node point N1 and the node point N2. Receive the determination result of the touch sensing circuit unit and the touch sensing circuit unit to supply power. It is a current interruption protection circuit consisting of a control unit for supplying or blocking and a switching unit having a relay function that operates with an electrical signal of the control unit.

Discharge lamp, current, interruption, protection circuit, human body, contact, detection

Description

Current interception protection circuit

1 is a block diagram of a current blocking protection circuit according to the present invention.

2 is a specific circuit diagram of a current blocking protection circuit according to the present invention.

3 is a specific circuit diagram of a touch sensing circuit unit of a current interruption protection circuit according to the present invention.

** Explanation of symbols on the main parts of the drawing **

10: transformer 11: transformer T1

12: transformer T2 13: transformer high voltage side

14: transformer low pressure side 20: discharge lamp

30: node part 31, 41: node point N1

32, 42: node point N2 33: pull-down resistor R1

34 pull-down resistor R2 40 touch sensing circuit

43: comparator 44: reference voltage (Vref)

45: output Vc 46: transistor Q1

47: Transistor Q2 48: Emitter Power Ve of Q1

50: control unit 60: switching unit

The present invention relates to a protection circuit for outputting a high frequency and high voltage ballast for lighting a discharge lamp of a fluorescent lamp or a backlight unit of a display device, or an output circuit when a human body contacts a high voltage output part while an inverter is being driven.

It is used in the structure which the ballast is connected to discharge lamps, such as a metal-halide bulb and fluorescent lamp which are typical discharge lamps, and every said discharge lamp.

Therefore, in the case of using a large number of discharge lamps, it is a matter of course that a number of ballasts suitable for the number is required.

In addition, an inverter for the backlight unit is essential to drive an LCD (LCD) backlight unit used in a display device.

In order to turn on the fluorescent lamp or the backlight unit of the display device, a ballast or an inverter that outputs high frequency and high voltage must be used. However, since the output signal of the ballast or inverter is high voltage of high frequency, when a human body touches the high voltage output part, an electric shock occurs. There was a problem of a safety accident.

The present invention was devised to solve the above problems, and in addition to the function of blocking the output by detecting when the human body touches the high voltage output part while driving the ballast or inverter, it detects an abnormality of an electrode such as a high frequency, a high voltage transformer and a discharge that is a load The purpose is to provide a function.

Another object of the present invention is to use a non-inductive resistance (nonninductive resistance) having a value of 2000 [Ohm] for the human body corresponding to the current type passing through the inductive resistance corresponds to the output frequency of the ballast or inverter The purpose is to prevent the periodic current from flowing.

Therefore, the present invention uses a discharge lamp lighting device equipped with a human body contact detection circuit, voltage imbalance and transformer defect caused by problems such as short circuit of the human body, short circuit of the wire, excessive wiring capacity, electrode abnormality or failure of the discharge lamp, etc. The purpose is to prevent the electric shock by preventing the power supply to the load by the operation of the human body contact detection circuit.

In order to achieve the above object, the present invention is designed to block the output when a human body contacts the high voltage output part while driving a ballast or inverter that outputs high frequency and high voltage to turn on a discharge lamp of a fluorescent lamp or a backlight unit of a display device. In the protection circuit,

A transformer unit configured to apply a voltage to the discharge lamp or the backlight unit, the transformer T1 and the transformer T2 which are in frequency synchronization and operate in reverse phase with each other; and

A node unit having a node point N1 and a node point N2 connected to the transformer low voltage side of the transformer unit one-to-one and having a voltage formed by a pull-down resistor;

A touch sensing circuit unit configured to compare a voltage formed at the node point N1 and the node point N2 with the reference voltage Vref having a constant voltage and detect an abnormality in human body contact and discharge, etc .; and

A control unit for supplying or cutting off power in response to the determination result of the contact sensing circuit unit; and

And a switching unit having a relay function that operates as an electrical signal of the control unit.

Hereinafter, with reference to the accompanying drawings to describe the present invention in detail.

1 is a block diagram of a current blocking protection circuit according to the present invention.

As shown in FIG. 1, the overall configuration of the current blocking protection circuit includes a transformer 10 having two transformers in which a secondary winding includes a transformer high voltage side 13 and a transformer low voltage side 14. 13 and the touch sensing circuit unit 40 and the touch sensing circuit unit receiving the voltage of the node unit 30 and the node unit 30 connected to the discharge lamp 20 connected to the transformer low voltage side 14. The control unit 50 controls the power of the discharge lamp 20 as a result value of the 40 and a switching unit 60 that operates by receiving a signal from the control unit 50.

2 is a specific circuit diagram of a current interruption protection circuit according to the present invention.

As shown in FIG. 2, the transformer unit 10 includes a transformer T1 (11) and a transformer T2 (12), which are in frequency synchronization, and the transformer T1 (11) and the transformer T2 (12) are out of phase with each other. It works.

Here, the transformer high voltage side 13 of the transformer T1 (11) and the transformer T2 (12) is connected to the discharge lamp 20, the voltage of the transformer high voltage side (13) of the transformer T1 (11) and transformer T2 (12) is If each of Vs, the voltage applied to the discharge lamp 20 is 2Vs.

In addition, the node part 30 includes a pull-down resistor R1 33 and a pull-down resistor R2 that are connected one-to-one with the transformer T1 11 and the transformer low voltage side 14 of the transformer T2 12. A voltage is formed by the 34 and the voltage applied to the pull down resistor R1 33 and the voltage applied to R2 34 are also out of phase with each other, so the pull down resistor R1 33 is in a normal state. And R2 (34) have the same value, the node point N1 (31) and the node point N2 (32) of the node portion 30 are in phase with each other, so that the node point N1 (31) and the node point N2 (32) At the time of contact, the voltage becomes 0 [V].

That is, the node 30 has a voltage of 0 [V] when the voltage applied to the pull down resistors R1 33 and R2 34 of the low voltage side 14 of the transformer driven in the reverse phase in the normal state is increased. It is characterized by.

Referring to the operation of the current blocking protection circuit, when the ballast or the inverter of the discharge lamp 20 is driven while the human body (2000 [Ohm] resistance) is in contact with the transformer high voltage side 13 Transformer outputs have an equivalently low load impedance, resulting in a lower output voltage. Therefore, the voltages of the node point N1 31 and the node point N2 32 of the node portion 30 have different values, and the voltage of the contact point even when the node point N1 31 and the node point N2 32 are in contact with each other. Does not become 0 [V] and maintains a constant value.

If a human body (2000 [Ohm] resistance) or the like comes into contact with the high voltage side 13 of the transformer while the ballast or the inverter of the discharge lamp 20 is being driven, the node point N1 31 and the node point N2 32 are contacted at the instant of contact. Glitch of an impulsive contact noise component occurs, and even when the node point N1 (31) and the node point N2 (32) are in contact with each other, only the periodic voltage component voltage disappears and the glitch component remains.

As described above, the contact point voltage of the node point N1 31 and the node point N2 32 of the node unit 30 determines whether the human body is in contact, and the node point N1 31 and the node point N2 32 are in contact with each other. When the voltage of the point rises above a certain level, or when glitches or noise components of a periodicity are detected, an error signal is transmitted to the controller 50 to cut off the output.

3 is a detailed circuit diagram of the touch sensing circuit unit of the current interruption protection circuit according to the present invention.

As shown in FIG. 3, the node point N1 41 and the node point N2 42 are in contact with each other and are connected to the non-inverting input of the comparator 43 of the touch sensing circuit 40, and to the inverting input of the comparator 43. The reference voltage Vref 44 having a constant value is always connected.

Here, referring to the operation principle of the comparator 43, if the non-inverting input voltage is greater than the inverting input voltage, the output voltage is high, and conversely, if the non-inverting input voltage is less than the inverting input voltage, the output voltage is low. )

The reference voltage (Vref) 44 is set to the maximum voltage deviation of the node point N1 (41) and the node point N2 (42) allowed in the normal state, so that the transformer T1 ( 11) even when excessive deviation between the transformer T2 (12) or the voltage difference between the two electrodes of the discharge lamp 20 is excessive, it can be protected by blocking the operation.

As described above, the noise component whose voltage at the node point N1 41 and the node point N2 42 which are the non-inverting input values of the comparator 43 is larger than the reference voltage Vref 44 which is the inverting input value of the comparator 43. In this case, the output of the comparator 43 becomes Vc 45, and the comparator output Vc 45 drives the NPN transistor Q2 47 to output an error signal through the collector of the PNP transistor Q1 46.

In addition, the comparator 43 is an output holding circuit including the PNP transistor Q1 46 and the NPN transistor Q2 47 that store values to output a continuous error signal even when the non-inverting input is a momentary signal of a glitch component. Make up.

Therefore, the touch sensing circuit unit 40 outputs an error signal until the emitter power supply Ve 48 of the PNP transistor Q1 46 is canceled (reset).

Therefore, the touch sensing circuit unit 40 detects a voltage difference between the transformer T1 11 and the transformer T2 12 of the transformer unit 10 and the noise generated when contacting the body, thereby detecting a human body connection situation. In addition to the human body contact is a current blocking protection circuit characterized in that it detects and cuts the voltage imbalance caused by the load electrode abnormality and the transformer imbalance of the transformer 10.

Although the preferred embodiment according to the present invention has been described as described above, the present invention is not limited to the above-described embodiment, and in the field to which the present invention belongs without departing from the gist of the present invention as claimed in the following Utility Model Claims. Anyone with ordinary knowledge will have the technical spirit of the present invention to the extent that various modifications can be made.

As discussed in detail above. The current cut-off protection circuit according to the present invention compares the voltage generated by the pull-down resistor connected to the low voltage side of the transformer with a comparator to cut off the current to prevent the risk of electric shock in advance, thereby preventing the occurrence of a safety accident. have.

In addition, the current cut-off protection circuit according to the present invention is a power supply to the load side by the operation of the human body contact detection circuit, the voltage imbalance and transformer failure caused by problems such as short circuit of the wiring, line leakage, excessive wiring capacity, in addition to the human body contact. This prevents electric shock by preventing the supply.

Claims (6)

In the protection circuit to cut off the output when a human body touches the high voltage output part while driving the ballast or inverter driving high frequency and high voltage to turn on the discharge lamp of the fluorescent lamp or the backlight unit of the display device, A transformer unit configured to apply a voltage to the discharge lamp or the backlight unit, the transformer T1 and the transformer T2 which are in frequency synchronization and operate in reverse phase with each other; A node unit having a node point N1 and a node point N2 connected to the transformer low voltage side of the transformer unit one-to-one and having a voltage formed by a pull-down resistor; A touch sensing circuit unit for comparing the voltage formed at the node point N1 and the node point N2 with the reference voltage Vref having a constant voltage and detecting an abnormality in human body contact and discharging; A control unit configured to supply or cut power by receiving a determination result of the touch sensing circuit unit; A switching unit having a relay function operating as an electrical signal of the control unit; Current blocking protection circuit. The method of claim 1, And said node portion becomes 0 [V] when the voltage applied to the pull-down resistor on the low voltage side of the transformer driven in the reverse phase in the normal state becomes 0 [V]. The method of claim 1, And determining whether human body contact is made using the connection point voltages of the node point N1 and the node point N2 of the node portion. The method of claim 1, And the reference voltage Vref of the touch sensing circuit unit is set to a maximum value of the voltage deviation between the node point N1 and the node point N2 of the node portion allowed in the normal state. The method of claim 1, The touch sensing circuit unit detects a voltage difference between the transformer T1 and the transformer T2 of the transformer and a noise generated when contacting to detect a human body connection situation. The method of claim 1, The touch detection circuit unit detects and cuts a voltage imbalance due to a load electrode abnormality and a transformer failure in addition to the human body contact, and cuts off the current blocking protection circuit.

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