Lighting control circuit, lamp, and lighting control method using the lighting control circuit

• US 9,271,350 B2
• Filed: 08/29/2013
• Issued: 02/23/2016
• Est. Priority Date: 08/31/2012
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Urano, Masaharu, Nakashima, Hidefumi, Hagiwara, Shigemi
• Primary Examiner(s): Lam, Tuan T
• Application Number:
  US14/013,455
• Publication Number:
  US 20140062320A1
• Time in Patent Office: 908 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H05B 45/3578 Emulating the electrical or functional characteristics of discharge lamps
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A lighting control circuit includes a rectifier connected to an electric ballast to which a commercial AC power is supplied, and configured to convert an AC to a DC, a series light emitter a plurality of solid-state light-emitting elements is connected in series, a smoothing capacitor provided in parallel with the series light emitter in a current supply line between the rectifier and the series light emitter, and configured to eliminate an AC component included in the DC from an output side of the rectifier, and a switching control circuit configured to generate an output voltage equal to an output voltage from the electric ballast when a fluorescent lamp starts up upon the connection of the fluorescent lamp to the electric ballast as a startup voltage in the startup of the series light emitter.

Claims

1. A lighting control circuit comprising:

a rectifier connected to an electric ballast to which a commercial AC power is supplied, and configured to convert an AC to a DC output;

a smoothing capacitor provided in parallel with a series light emitter in a current supply line between the rectifier and the series light emitter, and configured to eliminate an AC component included in the DC output from an output side of the rectifier;

an impedance element provided in series in the current supply line to generate an output voltage as a startup voltage in startup of the series light emitter, said output voltage applied in the startup of the series light emitter being equal to an output voltage from the electric ballast when a fluorescent lamp, connected instead of the series light emitter to the electric ballast, starts up while connected to the electric ballast;

a short-circuiting switching element provided in parallel with the impedance element; and

a timer control circuit configured to short-circuit the short-circuiting switching element after a predetermined time has passed since the startup of the series light emitter, wherein

the output voltage applied to the series light emitter in the startup of the series light emitter is equal to the output voltage from the electric ballast when the fluorescent lamp starts up while connected instead of the series light emitter to the electric ballast, and the output voltage from the electric ballast is set to be lower than the startup voltage after a predetermined time has passed since the startup of the series light emitter.

7. A lamp distinct from said fluorescent lamp and comprising:

the lighting control circuit according to claim 1; and

a series light emitter including a series connector of a plurality of solid-state light emitting elements.

2. A lamp comprising:

a straight tube, both ends of which are sealed by a cap having a pair of electrode pins,

the straight tube including inside thereof;

a rectifier connected to an electric ballast to which a commercial AC power is supplied, and configured to convert an AC to a DC output;

a smoothing capacitor provided in parallel with a series light emitter in a current supply line between the rectifier and the series light emitter, and configured to eliminate an AC component included in the DC output from an output side of the rectifier;

an impedance element provided in series in the current supply line to generate an output voltage as a startup voltage in startup of the series light emitter, said output voltage applied in the startup of the series light emitter being equal to an output voltage from the electric ballast when a fluorescent lamp, connected instead of the series light emitter to the electric ballast, starts up while connected to the electric ballast;

a short-circuiting switching element provided in parallel with the impedance element; and

a timer control circuit configured to short-circuit the short-circuiting switching element after a predetermined time has passed since the startup of the series light emitter, wherein

the output voltage applied to the series light emitter in the startup of the series light emitter is equal to the output voltage from the electric ballast when the fluorescent lamp starts up while connected instead of the series light emitter to the electric ballast, and the output voltage from the electric ballast is set to be lower than the startup voltage after a predetermined time has passed since the startup of the series light emitter.

3. A lighting control method of a lamp in which a series light emitter made up of a series connector including a plurality of solid-state light-emitting elements is provided inside a straight tube, both ends which are sealed by a cap having a pair of electrode pins, and the lamp being used instead of a fluorescent lamp by connecting to an electric ballast to which a commercial AC power is supplied, the lighting control method comprising:

providing an impedance element in a current supply line which supplies a current to the series light emitter upon electric connection of a smoothing capacitor in parallel with the series light emitter, and providing a short-circuiting switching element in parallel with the impedance element;

a control step of applying an output voltage as a startup voltage in startup of the series light emitter and equal to a startup voltage output from the electric ballast when the fluorescent lamp, connected instead of the series light emitter to the electric ballast, starts up while connected to the electric ballast; and

a control step of setting the output voltage from the electric ballast to be lower than the startup voltage after a predetermined time has passed since the startup of the series light emitter.

4. The lighting control method according to claim 3 further comprising:

a control step of maintaining the short-circuiting switching element in an open condition during a predetermined time after startup of the series light emitter.

5. The lighting control method according to claim 3 further comprising:

a control step of maintaining a current supply line which supplies a current to the series light emitter upon the electric connection of a smoothing capacitor in parallel with the series light emitter in an open condition during the predetermined time after startup of the series light emitter.

6. The lighting controlling method according to claim 3, wherein the output voltage from the electric ballast is set to be lower than the startup voltage by switching the connection condition of the series light emitter from a series connection condition to a parallel connection condition made up of series connection of a plurality of solid-state light-emitting elements.