JP3118458U - Fluorescent lamp current limit start electronic ballast - Google Patents

Abstract

Provided is a fluorescent lamp current limit starting electronic ballast with improved light emission control of a fluorescent lamp.
[Solution]
The fluorescent lamp current limit start electronic ballast is composed of a rectifier circuit 1, a filter circuit 2, an oscillation circuit 3, a high-frequency pulse transformer 4, a choke coil 5, and a current limit circuit 7. The current limit circuit 7 has a current limit resistor R1 connected in series. In other words, controllable diodes are connected in parallel at both ends, and this is triggered by the high-frequency pulse transformer 4. When the lamp is lit, the current is limited and started. When the fluorescent lamp tube 6 is started and emits light, the high-frequency pulse transformer 4 A high frequency pulse voltage is generated to turn on the controllable diode, and the voltage is all turned on to cause the fluorescent lamp tube 6 to emit light.
[Selection] Figure 1

Description

  The present invention relates to a fluorescent lamp current limit starting electronic ballast, in which a current limiting resistor is connected in series to a power source, a controllable diode is connected in parallel across the current limiting resistor, and this is triggered by a pulse transformer to limit the current when lighting. When the fluorescent lamp tube is started, the pulse transformer generates a high-frequency pulse voltage, and the controllable diode is turned on, so that all the voltage is passed to the fluorescent lamp tube to emit light, and the excessive current at the moment of starting The present invention relates to a fluorescent lamp current limit starting electronic ballast that prevents starting difficulties and failure and achieves practical effects.

Known fluorescent lamp electronic ballasts are mostly composed of a rectifier circuit, a filter capacitor, a pulse transformer, and a choke coil. The rectifier circuit converts alternating current into direct current, charges this with a capacitor, performs filtering, and then pulses. Provide to transformer to make fluorescent tube emit light. This has the following disadvantages:
1. The filter capacitor is charged quickly at start-up and the current is too large.
2. If electricity flows immediately after a momentary power failure, the starting current is too large, and an inrush current is generated in the filter capacitor, causing failure.
3. Since the filter capacitor is rapidly charged at the start, the voltage is too high, and the starting current is too large, the fluorescent lamp tube has a certain destructive action, and both ends tend to turn black, and the life of the fluorescent lamp tube is greatly shortened.
4). There is no protection when the output or circuit is short-circuited, and danger is likely to occur.
JP 2001-155889 A

  It is an object of the present invention to provide a fluorescent lamp current limit start electronic ballast that solves the drawbacks of the known techniques and prevents an excessive current at the start of the start, difficulty in starting, and occurrence of a failure.

In order to solve the above-mentioned problems, the present invention provides a fluorescent lamp current limit starting electronic ballast having the following features.
1. The fluorescent lamp current limit start electronic ballast according to claim 1 is a fluorescent lamp current limit start electronic ballast comprising a rectifier circuit, a filter circuit, an oscillation circuit, a high frequency pulse transformer, a choke coil, and a current limit circuit. The rectifier circuit includes several diodes, converts an AC power source into a DC power source, the filter circuit includes two series-connected capacitors, removes noise in the DC power source, and the oscillation circuit has 2 Each transistor is connected in parallel to the capacitor of the filter circuit and connected to the high-frequency pulse transformer, and the two transistors are alternately turned on and off. By exhibiting, high-frequency oscillation can be generated, and direct current can have a high-frequency effect. Connected to the oscillation circuit, the choke coil, and the fluorescent lamp tube, a pulse wave effect can be generated, thereby converting the high frequency current produced by the oscillation circuit into a high frequency pulse and passing through the choke coil to the fluorescent lamp tube The current limiting circuit includes a unidirectional controllable diode SCR and a current limiting resistor, which is connected to the capacitor of the filter circuit and the high frequency pulse transformer, The current limiting resistor limits the current and charges the capacitor of the filter circuit with a small current, and the unidirectional controllable diode SCR is triggered by the high-frequency oscillation signal of the high-frequency pulse transformer to conduct, and an instantaneous excessive current Capable of eliminating the damage to the capacitor due to overcurrent and preventing the short circuit and failure due to excessive current Characterized by comprising in.
2. The fluorescent lamp current limit starting electronic ballast according to claim 2 is the case of claim 1, wherein the current limit circuit employs a bi-directional controllable diode TRIAC to control conduction. It is characterized by that.

The following effects and advantages can be obtained by the control of the present invention.
1. Easy start-up: The present invention is a current-limited start, and the current is controlled below nano ampere and can be started easily.
2. Extending the life of the fluorescent lamp tube 6: The current starting resistance R1 of the current limiting circuit 7 reduces the instantaneous starting current, thereby reducing the damage to the fluorescent lamp tube 6 caused by the instantaneous high current and extending the service life.
3. Preventing damage due to current: When a short circuit occurs due to a short circuit or a failure of the fluorescent lamp tube 6, or when a circuit failure occurs, the SCR is not oscillated to be non-conductive, but is limited to a current limiting resistor and is in a small current state. It can prevent damage caused by a large current.
4). Flickerless: The high-frequency pulse is provided to the fluorescent lamp tube 6 by the oscillation circuit 3 and the high-frequency pulse transformer 4 so that the fluorescent lamp tube 6 emits light. it can.

  As shown in FIG. 1, when used for an AC power supply 220V and the fluorescent lamp tube 6 exhibits 4W-40W (or AC power supply 110V fluorescent lamp tube 4W-20W), four diodes D1, D2, D3, The bridge type rectifier circuit 1 is configured by adopting D4. In other words, it exhibits “full wave rectification”. Therefore, a unidirectional controllable diode SCR can be adopted as the drive diode of the current limiting circuit 7. When the fluorescent lamp tube 6 is desired to emit light, electricity is rectified from the rectifier circuit 1 to a direct current, passed through the current limiting circuit 7, and then charged to the capacitors C2 and C3 of the filter circuit 2. When the capacitance is saturated, the transistors TR1 and TR2 of the oscillation circuit 3 are turned on to generate oscillation and generate a high frequency. Further, the high-frequency pulse transformer 4 generates a high-frequency pulse, and the unidirectional controllable diode SCR of the current limiting circuit 7 is also turned on so that the fluorescent lamp tube 6 can emit light by supplying power normally.

  In particular, the current limiting circuit 7 of the present invention is provided with the unidirectional controllable diode SCR and the current limiting resistor R1, so that a high frequency pulse voltage can be generated by a high frequency pulse transformer to turn on the SCR. Since the resistor R1 is provided, the current value can be controlled not to become too large. That is, the capacitors C2 and C3 of the filter circuit 2 can be charged with a small current. For example, the current limiting resistance R1 is 47KΩ, the voltage is 220V, and the current value is 220V ÷ 47KΩ = 0.005A. This current is the maximum current that can pass through 0.005A. Therefore, the instantaneous start-up of the power supply is limited to a small current of 0.005 A and drives the fluorescent lamp 6.

  The present invention can also be used for AC 110V, 40W and 30W fluorescent lamp tubes 6. As shown in FIG. 2, the 110V, 40W (30W) fluorescent lamp tube 6 does not emit light unless it is "double pressure". The circuit 10 is rectified by two diodes D1 and D2, so as to obtain a doubled direct current, and the current limiting circuit 70 employs a bidirectionally controllable diode TRIAC and also includes a current limiting resistor R1. To do. If it carries out as mentioned above, the effect of control light emission will be acquired also to a 110V, 40W (30W) fluorescent lamp tube, and it will carry out after the start-up oscillation with a small electric current restricting current, and the effect of circuit output short circuit protection will also be acquired.

It is a circuit diagram of the structure of the present invention. It is a circuit diagram of the structure of the Example which applied this invention to 110V40W and 30W.

Explanation of symbols

1, 10 Rectifier circuit 2 Filter circuit 3 Oscillator circuit 4 High-frequency pulse transformer 5 Choke coil 6 Fluorescent lamp tube 7, 70 Current limiting circuit D1, D2, D3, D4 Diode C2, C3 Capacitor R1 Current limiting resistor R2, R3, R4 Bias Resistor TR1, TR2 Transistor SCR Unidirectional controllable diode TRIAC Bidirectional controllable diode

Claims (2)

A fluorescent lamp current limit starting electronic ballast composed of a rectifier circuit, a filter circuit, an oscillation circuit, a high frequency pulse transformer, a choke coil, a current limit circuit,
The rectifier circuit includes several diodes, converts an AC power source into a DC power source,
The filter circuit includes two capacitors connected in series, removes noise in the DC power supply,
The oscillation circuit is configured to include two transistors and a bias resistor, and each transistor is connected in parallel to the capacitor of the filter circuit, and is connected to the high-frequency pulse transformer, and the two transistors are connected to each other. By alternately showing conduction and non-conduction, the occurrence of high-frequency oscillation is obtained, so that the direct current has a high-frequency effect,
The high-frequency pulse transformer is connected to the oscillation circuit, the choke coil, and the fluorescent lamp tube, and can generate a pulse wave effect, whereby the high-frequency current produced by the oscillation circuit is converted into a high-frequency pulse and passed through the choke coil. The high frequency voltage required for the fluorescent lamp tube can be provided,
The current limiting circuit includes a unidirectional controllable diode SCR and a current limiting resistor, which are connected to the capacitor of the filter circuit and the high frequency pulse transformer, and the current limiting resistor limits the current. The capacitor of the filter circuit is charged with a small current, and the unidirectional controllable diode SCR is triggered and conducted by the high-frequency oscillation signal of the high-frequency pulse transformer, thereby eliminating the damage of the capacitor due to an instantaneous excessive current and the excessive current. A fluorescent lamp current limit starting electronic ballast characterized by being able to achieve an effect of preventing a circuit short circuit / fault. 2. The fluorescent lamp current limit start electronic ballast according to claim 1, wherein the current limit circuit employs a bi-directional controllable diode TRIAC to control conduction.

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