JPH067197U - Fluorescent lamp lighting device - Google Patents

Abstract

(57) [Summary] [Object] To provide a fluorescent lamp lighting device having an auxiliary power supply circuit for an oscillation control circuit that is low in cost, space-saving, and has low power loss. [Constitution] In a fluorescent lamp lighting device that forms a series resonance circuit with a current limiting inductance CH1 at the output of the fluorescent lamp inverter circuit 19 and a capacitor C3 arranged in parallel with the fluorescent lamp FL, the output current load feedback path is connected in series. A capacitor C4 for cutting a DC component is inserted into the capacitor and the output current io is shunted so that the auxiliary power supply of the oscillation control circuit 12 of the inverter circuit is rectified only the AC component of the ripple voltage generated in the capacitor for cutting the DC component. The fluorescent lamp lighting device 20 configured to be operated by the DC power supply V obtained by the above.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fluorescent lamp lighting device. More specifically, the present invention relates to a fluorescent lamp lighting device, and more specifically, a rippleless voltage generated at both ends of a DC component cutting capacitor inserted in series in an output current load feedback path is adjusted to reduce a transformerless size. The present invention relates to auxiliary power supply for an oscillation control circuit that realizes power loss, a minimal number of parts, space saving, and low price.

[0002]

[Prior art]

 Generally, for the auxiliary power supply of the oscillation control circuit of the switching transistor in the inverter circuit of the fluorescent lamp lighting device, an example of using a small power transformer as shown in FIG. 3 or switching output in the inverter circuit as shown in FIG. In most cases, the A point) is stepped down by a pulse transformer, rectified and smoothed, and the auxiliary power V is supplied. Hereinafter, each of the conventional examples will be described.

In the circuit of FIG. 3, the AC power supply 1 input to the power supply transformer T1 is reduced in voltage by the transformer and rectified by the next full-wave rectifier diode D1. After rectification, it is smoothed by the smoothing capacitor C 1 to obtain the low voltage DC power supply V.

Although the above-mentioned circuit has the advantage that the voltage on the low-voltage side and the power can be set freely with the most basic circuit configuration, since the power transformer T1 is used, there are potential power loss, weight, and It has drawbacks in terms of occupied volume and cost, and its use is necessarily limited.

A circuit 10 in FIG. 4 is an example of a transistor inverter circuit in a fluorescent lamp lighting circuit, and includes an auxiliary power supply generation circuit 6 for supplying DC power to an oscillation control circuit 8.

The circuit operation of the auxiliary power supply generation circuit 6 in this circuit is such that the DC component from the switching output stage A of the MOSFETs Q1 and Q2 is cut by the capacitor C2 and the eddy current is suppressed by the resistor R1, and then the pulse transformer T2 is turned on. The voltage is stepped down via the diode D2, rectified by the diode D2 and smoothed by the smoothing capacitor C1 to obtain the DC power supply V.

The circuit has an advantage that a desired voltage can be freely obtained by changing the winding ratio of the pulse transformer and power loss can be relatively neglected, but the basic circuit configuration is the same as that of FIG. There are similar problems in terms of increased occupied volume and increased cost due to the use of transformers.

In FIG. 4, the output Vout of the inverter circuit 10 is a high-frequency AC voltage (about 50 kHz), and a fluorescent lamp (not shown) having a comparatively small power consumption is connected via a current limiting inductor for lighting. , It supplies power to the fluorescent lamp load circuit.

At this time, the oscillation control circuit 8 is a circuit for controlling the gate voltage of the switching transistors Q1 and Q2 at intermittent frequency to stabilize the output, and the DC power supply to the control circuit is 0. Approximately 0.5 W is usually required for fluorescent lamp lighting devices.

[0010]

[Problems to be solved by the device]

 As described above, the auxiliary power supply for the control circuit for oscillation (switching) in the fluorescent lamp lighting device does not need a large amount of power to drive a load, and a low voltage and a small amount of power sufficient to supply the gate potential of the transistor are sufficient. However, as shown in the example of FIG. 3, a circuit that uses the power supply transformer T1 for stepping down causes a power loss more than the required power, and also becomes a large heat source as well as a power loss. Therefore, there was a problem in adopting the circuit in response to an increasing demand for energy saving and miniaturization.

Even in the case of the auxiliary power generation circuit 6 in FIG. 4, in addition to the problems of occupied volume and cost due to the use of the pulse transformer T2, the circuit becomes complicated and the switching circuit is adversely affected. Detailed consideration and consideration are required such as design consideration to ensure that the circuit does not hinder the power and the operation of the entire circuit in the range that is not given, and the adoption of high withstand voltage parts to use the switched high voltage. .

The present invention has been made in view of the above circumstances, and the auxiliary power supply of the capacity required by the oscillation control circuit 8 is configured by a simple circuit, and the fluorescent lamp can be used as in the case of replacing a fluorescent lamp. (EN) Provided is a fluorescent lamp lighting device that avoids the danger of disconnecting the lamp from the circuit, realizes low cost, space saving, and low power loss.

[0013]

[Means for Solving the Problems]

 The present invention is a fluorescent lamp lighting device that forms a series resonance circuit by a current limiting inductance at the output of the fluorescent lamp inverter circuit and a capacitor arranged in parallel with the fluorescent lamp, and a DC component is connected in series to the output current load feedback path. It is obtained by inserting a cutting capacitor and shunting the output current to rectify only the AC component of the ripple voltage generated in the DC component cutting capacitor to supply auxiliary power to the oscillation control circuit of the inverter circuit. The above object is achieved by providing a fluorescent lamp lighting device characterized by being operated by a DC power supply.

[0014]

[Action]

 The DC component cut capacitor inserted in series in the output current return path works to cut the entire DC voltage flowing to the fluorescent lamp, avoiding the risk of disconnecting the fluorescent lamp from the circuit as when replacing the fluorescent lamp. It

In the steady state, a DC voltage including a ripple voltage of several volts is generated across the capacitor. Therefore, by shunting the output current and rectifying and smoothing the ripple voltage (AC), an auxiliary power supply for the oscillation control circuit can be obtained.

The power to be supplied is mainly determined by the capacity ratio of the shunt capacitor and the DC shunt capacitor of the auxiliary power circuit.

This auxiliary power supply generation circuit has a simple circuit configuration because it does not use a transformer, has a negligible power loss, and has a margin in terms of weight, space, and cost.

[0018]

【Example】

 An embodiment of an auxiliary power supply circuit of an oscillation control circuit in a fluorescent lamp lighting device of the present invention will be described with reference to the drawings.

FIG. 1 shows a so-called half-bridge type inverter circuit 19 having two NMOS switching transistors Q1 and Q2, a current limiting inductance CH1 connected to the inverter output, and a fluorescent lamp FL which are arranged in parallel. In the fluorescent lamp lighting device 20 that forms a series resonance circuit with the capacitor C3, a DC component cutting capacitor C4 is inserted in series in the load feedback path of the inverter output current io, and the output current io is reduced. The auxiliary power supply of the oscillation control circuit 12 of the inverter circuit 19 is diverted by C5, and only the AC component of the ripple voltage generated in the DC component cutting capacitor C4 is rectified by the rectifying diodes D4 and D5 to smooth it. The DC power source V obtained by smoothing the capacitor C6 is used.

The resistor R3 acts as a protection resistor against a pulse current and also acts as a limiter for the maximum value current.

The operation of the inverter circuit 19 is such that when the commercial AC power supply 1 (100 V or 200 V) is first applied, it is rectified and smoothed by the full-wave rectifier D1 and the smoothing capacitor C1 to become a DC voltage, and the NMOS switching transistor Q1 , Q2 drain current is supplied. Further, the start signal is flows through the resistors R2 and D3 to start the start circuit 16. The start circuit is a circuit for applying the gate voltages of Q1 and Q2 via a pulse transformer (not shown) in the oscillation control circuit 12, and the oscillation control circuit has an oscillation circuit and Q1 in a steady state after the start. , Q2 push-pull operation is controlled. The power supply of the oscillation control circuit 12 in the steady state after Q1 and Q2 are turned on once is supplied by the auxiliary power supply circuit 14.

Immediately after the power is turned on, a DC current flows through the load circuit, the DC component cut capacitor C4 is charged until the voltage becomes half of the voltage across C1, and after a few seconds, it shifts to a steady state.

The voltage waveform across C4 in the steady state has a DC voltage component 17 (63 Vdc in the diagram) and a ripple voltage component 18 of the oscillation frequency (48 kHz in the diagram), as shown in FIG. 2, for example.

In the circuit 20, the auxiliary power supply circuit 14 for the oscillation control circuit according to the present invention is composed of a shunt capacitor C5, a resistor R3 and rectifying / smoothing diodes D4 and D5, and supplies a DC power V.

The power to be taken out is mainly determined by the capacity ratio of C4 and C3, but according to the study by the present inventor, an auxiliary power supply of about 0.5 W can be easily obtained and the power supply voltage As the voltage is lowered to about a dozen V which is easy to handle, it is possible to realize low cost, low loss and space saving without consideration of withstand voltage.

According to the measurement by the present inventor, in the one-lamp fluorescent lighting device using FL30S for the fluorescent lamp of FIG. 1, when the inverter circuit is output at an AC input power of 100 Vac and an oscillation frequency of 48 kHz, When a C4 capacitance of 0.2 μF and a C5 capacitance of 0.1 μF are applied, the C1 voltage is 126 V, io = 0.533 A, the C4 DC voltage is 63 Vdc (half the C1 voltage), and the C4 ripple voltage is 9.2 Vac. (Effective value at amplitude Vmax13V in FIG. 2), the result that the DC voltage between C6 was 17.7 Vdc and i3 = 40 mA was obtained as the auxiliary power supply circuit of the oscillation control circuit 12. This is sufficient power for auxiliary power supply.

The auxiliary power supply circuit according to the present invention described above is mainly intended to rectify and supply only the AC component of the ripple voltage generated in the DC component cut capacitor. It goes without saying that the auxiliary power supply circuit is not limited to the fluorescent lamp lighting device having the above, but also an auxiliary power supply circuit as a power supply to the control circuit in the fluorescent lamp lighting device of the other type of inverter circuit based on the above idea.

[0028]

[Effect of device]

 The fluorescent lamp lighting device according to the present invention has the following effects because the auxiliary power supply circuit of the oscillation control circuit is configured as described above.

(1) Since the auxiliary power supply circuit of the oscillation control circuit is configured by an extremely simple circuit, it has an excellent effect that the circuit design is easy and versatile.

(2) Further, it has excellent effects of low cost, small power loss, and space saving due to no transformer.

(3) Since the DC voltage component is cut off, there is an excellent effect that the safety of handling the fluorescent lamp is enhanced.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a fluorescent lamp lighting device according to the present invention.

FIG. 2 is a voltage waveform diagram across a DC component cut capacitor in a steady state.

FIG. 3 is an auxiliary power generation circuit using a conventional small power transformer.

FIG. 4 is an auxiliary power supply generation circuit using a pulse transformer in a conventional transistor inverter circuit.

[Explanation of symbols]

 1 (commercial) AC power supply 6 Auxiliary power supply circuit 8 Oscillation control circuit 10 Transistor inverter circuit 12 Oscillation control circuit 14 Auxiliary power supply circuit 16 Start circuit 17 DC voltage component 18 AC ripple voltage component 19 Inverter circuit 20 Fluorescent lamp lighting device T1 Small power supply transformer D1 Full wave rectifier diode D2 to D5 Rectifier diode V Low voltage DC voltage Vout Inverter circuit output Q1 and Q2 NMOS switching transistor T2 Pulse transformer R1 to R3 Resistance C1 to C6 Capacitor CH1 Current limiting inductor FL Fluorescent lamp is start signal io ~ I3 current

Claims (1)

[Scope of utility model registration request] 1. A fluorescent lamp lighting device comprising a series resonance circuit composed of a current limiting inductance at the output of a fluorescent lamp inverter circuit and a capacitor arranged in parallel with the fluorescent lamp, wherein a direct current is connected in series to an output current load feedback path. DC obtained by rectifying only the AC component of the ripple voltage generated in the DC component-cutting capacitor by inserting the component-cutting capacitor and shunting the output current to supply auxiliary power to the oscillation control circuit of the inverter circuit. A fluorescent lamp lighting device characterized by being operated by a power supply.