KR900000503B1 - Apparatus for discharge lamps - Google Patents

Abstract

The circuit for improving the illumination efficiency utilizing high speed switching of a switching transistor in an inverter includes comparators (COMP1,COMP2) for converting signals of a multivibrator to rectangular signals for supplying the power to a lamp by alternative turning on the switching transistors (TR1,TR2), a comparator (COMP3) generating low level signal which prevents the operation of the multivibrator (3) when a resistor (R1) detects the large loss-current and a comparator (COMP4) for preventing the overheat of an inverter (2).

Description

Fluorescent lamp lighting device

1 is a detailed circuit diagram of a fluorescent lamp lighting apparatus of the present invention.

2 and 3 are each waveform diagram of FIG.

* Explanation of symbols for main parts of the drawings

1: power supply 2: inverter circuit

3: unstable multivibrator LP ₁ : fluorescent lamp

TR ₁ -TR ₆ : Transistor COMP ₁ -COMP ₄ : Comparator

The present invention relates to a fluorescent lamp lighting device of the other half-bridge type, and more particularly to a fluorescent lamp lighting device to improve the luminous efficiency and lighting characteristics by lighting the fluorescent lamp at a high frequency. In the conventional fluorescent lamp lighting device, the output terminal of the fluorescent lamp has several lines, so not only the external terminal of the ballast is complicated, but the overall structure is complicated, and even if a lot of heat is generated in the ballast, there is no safety device. There were many shortcomings to be followed.

In order to solve the above-mentioned drawbacks, the present invention can simplify the external terminal of the ballast by using two output lines of the fluorescent lamp side, and block the switching drive signal of the fluorescent lamp when the ballast is heated above a certain temperature. In order to prevent the risk of fire in advance, and to prevent unnecessary power consumption in the state that the fluorescent lamp is not inserted, it will be described in detail with reference to the accompanying drawings.

1 is a circuit diagram of a fluorescent lamp lighting device of the present invention, as shown here, the power switch (SW) and fuse (F), choke coil (L ₁ ) for preventing the initial inrush current, bridge diode (BD ₁ ), smoothing capacitor The output side of the power supply unit 1 composed of (C ₁ ) includes a switching transistor (TR ₁ , TR ₂ ) and a discharge initiating capacitor (C ₂ ), an overcurrent flow prevention and resonant choke coil (L ₂ ), and a resonance capacitor ( C ₃ ), (C ₄ ), fluorescent lamp (LP ₁ ), and connected to the input side of the inverter circuit section 2 composed of the loss current detection resistor (R ₁ ), and the resistor (R ₄ -R ₇ ) and the capacitor (C _The reference voltages Verf ₁ and Vref ₂ are respectively inputted to the inverting input terminals A, B of the unstable multivibrator 3 composed of ₅ , C ₆ and transistors TR ₃ and TR ₄ . a comparator (COMP _1), connected to its output terminals and each connected to a non-inverting input terminal of the (COMP ₂₎ to the base of the transistor _{(TR 5), (TR 6} ), and a transistor _{(TR 5), (TR 6} ) Cole Condenser (C ₇ ), (connecting primary side (T ₁₁ ), (T ₂₁ ) of transformer (T ₁ ), (T ₂ ) to the selector and connecting secondary side (T ₁₂ ), (T ₂₂ ) in parallel C ₈ ) and the bases of the switching transistors TR ₁ and TR ₂ through resistors R ₂ and R ₃ .

On the other hand, the resistor R ₁ for detecting the loss current of the inverter circuit part 2 is connected to the resistor R ₈ and the capacitor C ₉ and the non-inverting through the diode D ₅ and the resistor R ₉ . reference voltage to the input terminal (Vref ₃₎ connected to the inverting input terminal of the comparator (COMP ₃₎ that is applied and, more Mr (TH ₁₎ a resistor (R ₁₀₎ and a reference voltage to the inverting input terminal (Vref ₄₎ is applied Is connected to the non-inverting input terminal of the comparator (COMP ₄ ), and the output side (A), (B) of the unstable multivibrator (3) through the diode (D ₆ ), (D ₇ ), respectively, the comparator (COMP _3). ), (COMP ₄ ) is configured by connecting to the output side of the common, the operation and effect of the present invention configured as described in detail as follows.

When the power switch SW is short-circuited and AC power AC as shown in FIG. 2A is inputted, the AC power AC is rectified by the bridge diode BD ₁ , and FIG. It is output in a pulse wave waveform as shown in the figure, and the pulse wave waveform is smoothed as shown in (c) of FIG. 2 in the smoothing capacitor C ₁ and applied to the input side of the inverter circuit section 2, as will be described later. As the switching transistors TR ₁ and TR ₂ are turned on and off, the current waveforms through the switching transistors TR ₁ and TR _{2 become} as shown in FIG. On the other hand, the DC voltage (Vcc) is supplied to the waveform signal of a predetermined period as shown at the output side, the third degree (a), (b) the non-stable multivibrator (3) outputs as a comparator (COMP _1), Comparing the reference voltages Verf ₁ and Vref ₂ at (COMP ₂ ), respectively, the output terminals of the comparators (COMP ₁ ) and (COMP ₂ ) are shown in (c) and (d) of FIG. Similarly, the square wave path is output with a certain time difference.

In this way, when the square wave signal is output from the comparator COMP ₁ , the current amplifying transistor TR ₅ is turned on so that a current flows on the primary side T ₁₁ of the transformer T ₁ , and thus, the secondary side thereof. The voltage is induced at T ₁₂ to turn on the switching transistor TR ₁ . At this time, since the low potential signal is output to the output terminal of the comparator COMP ₂ and the transistor TR ₆ is turned off, the switching transistor TR ₂ is also turned off. On the contrary, when the square wave signal is output from the comparator COMP ₂ , the transistor TR ₆ is turned on so that the voltage is induced on the secondary side T ₂₂ of the transformer T ₂ , so that the switching transistor TR ₂ is turned on. The low potential signal is output to the output terminal of the comparator COMP ₁ so that the switching transistor TR ₁ is turned off. As described above, the switching transistors TR ₁ and TR ₂ are alternately turned on, and in particular, the comparators COMP ₁ and COMPP have a predetermined time difference according to the set values of the reference voltages Ver ₁ and Vref ₂ . _{Since the} square wave signal is output from ₂ ), the switching transistors TR ₁ and TR ₂ are not turned on at the same time.

As described above, when the switching transistor TR ₁ is turned on and the switching transistor TR ₂ is turned off, the output voltage of the power supply unit 1 is the switching transistor TR ₁ , the discharge initiating capacitor C ₂ , and the choke coil. (L ₂ ) and the capacitor (C ₄ ), when the switching transistor (TR ₁ ) is off and the switching transistor (TR ₂ ) is turned on, the output voltage of the power supply unit 1 is condenser (C ₃ ), choke coil L ₂ , the discharge start capacitor C ₂ , and the switching transistor TR ₂ .

Therefore, in the initial state in which the power switch SW is short-circuited, the high voltage is generated by the series resonant operation of the discharge start capacitor C ₂ and the choke coil L ₂ , and thus the fluorescent lamp LP ₁ starts to discharge. , one fluorescent lamp capacitor (LP ₁₎ is after the start of the discharge is, the reactive current that the fluorescent lamp, because current flows through the (LP ₁₎ capacitor for firing (C ₂₎ flows start the discharge (C ₂ ), There is no unnecessary power consumption.

On the other hand, where the fluorescent lamp the voltage across the large current flows that the resistance (R ₁₎ a (LP ₁₎ is equal does not occupied state, loss of the current detection resistor (R ₁₎ for a is higher, the resistance (R ₁₎ The voltage at both ends of is charged in the capacitor C ₉ through the diode D ₅ and the resistor R ₉ and applied to the inverting input terminal of the comparator COMP ₃ to be compared with the reference voltage Vref ₃ . Therefore, this time the reference voltage (Vref ₃₎ is a low potential signal to the output terminal of the release, but a set lower than the voltage applied to the inverting input terminal of the comparator (COMP ₃₎ the comparator (COMP ₃₎ is outputted, so that non-stable multi- Since the output side (A) and (B) signals of the vibrator 3 flow to the output terminal of the comparator COMP ₃ through the diodes D ₆ and D ₇ , the unstable multivibrator 3 starts the oscillation operation. The low-potential signal is continuously output to its output side (A) and (B), and accordingly, the switching transistors TR ₁ and TR ₂ remain off so that the fluorescent lamp LP ₁ is not inserted. This avoids unnecessary power consumption in the system.

Here, it is necessary to set the charging time constants of the resistor R ₉ and the capacitor C ₉ sufficiently long, in which case the fluorescent lamp LP ₁ is inserted for a certain time after the short circuit of the power switch SW. This is to prevent the oscillation operation of the unstable multivibrator 3 from being stopped. On the other hand, as the ambient temperature of the inverter circuit unit 2 rises, the resistance value of the dummyster TH ₁ increases, so that the voltage applied to the non-inverting input terminal of the comparator COMP ₄ decreases, thereby freezing the reference voltage Vref ₄ . placing the comparator to set (COMP ₄₎ of higher than the voltage applied to the non-inverting input terminal in the above temperature, and output the low-potential signal from the comparator (COMP _4), yiettara, unstable, as in the above-described multi-vibrator (3 ) Stops the oscillation operation and keeps the switching transistors TR ₁ and TR ₂ in the off state, so that the fluorescent lamp LP ₁ is not discharged, thereby preventing overheating.

On the other hand, in order to operate the unstable multivibrator 3 again in a state where the unstable multivibrator 3 has stopped oscillating as described above, the power switch SW may be opened and then shorted again to bring it to an initial state. . Since the comparators COMP ₁ and COMP ₂ operate as open collectors, the current amplifiers TR ₅ and TR ₆ are removed when the discharge lamp LP ₁ is for low power, and the comparator COMP ₁ ) Connect the primary terminals (T ₁₁ ) and (T ₂₁ ) of the transformers (T ₁ ) and (T ₂ ) directly to the output terminals of (COMP ₂ ).

As described in detail above, the present invention converts the output signal of the unstable multivibrator into a square wave to quickly control on / off of the switching transistor of the inverter circuit part, thereby improving the incremental efficiency of the fluorescent lamp and simplifying the overall structure. When two switching transistors are turned on at the same time, no overcurrent flows, and unnecessary power consumption is prevented when the fluorescent lamp is not inserted, and the ambient temperature of the inverter circuit portion rises above a certain temperature. In order to stop the operation of the inverter circuit portion has the effect of preventing the risk of fire in advance.

Claims (3)

As the AC power supply unit 1 and the switching transistors TR ₁ and TR ₂ are turned on and off by a commercial AC power source, the output voltage of the power supply unit 1 is converted to a high frequency to generate a fluorescent lamp. In the fluorescent lamp lighting device composed of the inverter circuit section (2) where LP ₁ ) is turned on, the output side (A) and (B) of the unstable multivibrator (3) are square wave conversion comparators (COMP ₁ ) and (COMP ₂ ), respectively. through transistor (TR _5), connected to the base of (TR6), a transistor (TR _5), the primary side of the transformer _{(T 1), (T 2} ) to the collector of _{(TR 6) (T 11,} ) and (T ₂₁ ), and the secondary side T ₁₂ and T _{22 thereof} are connected to the base side of the switching transistors TR ₁ and TR ₂ , and the resistor for detecting the loss current of the inverter circuit section 2 R ₁ ) is connected to the inverting input terminal of the capacitor C ₉ and the comparator COMP ₃ through the diode D ₅ and the resistor R ₉ , and to the output terminal of the comparator COMP ₃ . A fluorescent lamp lighting device, characterized in that the output side (A), (B) of the constant multi-vibrator (3) is connected via a diode (D ₆ ), (D ₇ ). _2. A fluorescent lamp lighting device according to claim ₁ , characterized in that the discharge start capacitor (C ₂ ) is connected in parallel to the discharge lamp (LP ₁ ) of the inverter circuit section (2). The non-inverting input terminal is configured by connecting the output terminal of the comparator COMP ₄ connected to the connection point of the dummyster TH ₁ and the resistor R ₁₀ to the output terminal of the comparator COMP ₃ . Fluorescent lamp lighting apparatus characterized in that.

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