JPH0482200A - Dc lighting of fluorescent lamp - Google Patents

Abstract

PURPOSE:To reduce loss in power by connecting a preheat-starting type fluorescent lamp having a lamp voltage of 1V to 89V to a power supply having a voltage not less than the lamp starting voltage through elements having impedance and the like. CONSTITUTION:To cope with the negative characteristics in discharge of a preheat-starting type lamp having a lamp voltage of 1V-89V at the time of DC lighting operation, an element or circuit is connected to a power supply; or an element having impedance or circuit is connected to a power supply which can provide a voltage not less than the lamp starting voltage by a kick voltage the element or the like is connected; or an element having impedance or circuit is connected to a power supply having a voltage not less than the lamp starting voltage; or a transformer is connected to such power supply. With the constitution, power loss can be reduced.

Description

Detailed Description of the Invention (A) Industrial application field Lighting field (B) Prior art Direct current lighting of fluorescent lamps requires the use of a ballast resistor to cope with the negative characteristics of the discharge of fluorescent lamps. This has not been put into practical use because of the large power loss.

(C) Problem to be solved by the invention In conventional AC lighting, the optical output waveform blinks with a fundamental frequency twice the power supply frequency, or
If you use the circuit of this invention, 9 flashes will not occur. Also, since there are only 9 flashes, the lamp life is not as short as with inverter systems.

Furthermore, when a coil such as a choke coil is used as in the past, the choke coil etc. contains a pure resistance.In this invention, a capacitor (1 in Figure 1) is used, which reduces power loss. did.

(D) Means for solving the problem A transient current for charging the smoothing capacitor and a load current to the lamp are passed through the capacitor 1 in Figure 1, and the terminal voltage of the smoothing capacitor is The load current at point A in Figure 1 turns off when the voltage becomes larger than the voltage (Figure 3). It can be obtained by

Therefore, it is possible to use a capacitor as a current limiting element even in an AC lighting circuit of a power source near a commercial frequency.

(F) Power saving was achieved compared to the case where a coil was used to cope with the negative characteristics of the discharge of the example lamp.

In addition, since the load current waveform at the 8 points in Figure 9 is a direct current as shown in Figure 9 and Figure 2, we were able to obtain a larger light output than when using a conventional AC lighting circuit.

(G) Effects of the invention Since the lamp current is a direct current as shown in Figure 1 and Figure 2, it was possible to obtain a greater light output than when using a conventional AC lighting circuit. In addition, in order to deal with the negative characteristics of the lamp's discharge, we used a capacitor instead of a coil as in previous models, resulting in power savings.

[Brief explanation of the drawing]

1 - Capacitor - 2 - Lamp 3 - Starter 4 - Noise prevention capacitor 5 - Smoothing coil 6 - Smoothing condenser 7 - Brillant 8 - Power supply

Claims (1)

[Claims] "1" In order to deal with the negative characteristic of lamp discharge, a direct current voltage is obtained by a bridge after passing through an element having a current limiting effect (drooping characteristic) such as a coil (choke coil, etc.) . "2" A capacitor is used as a current-limiting element in an AC lighting circuit near the commercial power frequency. ``3'' After this, rectify with a bridge to obtain a DC voltage. "4" After the circuit according to the third claim, the obtained DC voltage is used with a smoothing coil and a smoothing capacitor to obtain a DC current with less superimposition of AC components, and this is supplied to a fluorescent lamp.