Lighting device for semiconductor light emitting elements and illumination apparatus including same

• US 9,226,353 B2
• Filed: 02/08/2012
• Issued: 12/29/2015
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Esaki, Sana, Hiramatu, Akinori
• Primary Examiner(s): Taningco, Alexander H
• Assistant Examiner(s): LOTTER, DAVID E
• Application Number:
  US13/368,722
• Publication Number:
  US 20120200231A1
• Time in Patent Office: 1,420 Days
• Field of Search: 315/210, 315/291, 315/185.R, 315/192, 315/193, 315/246, 315/186, 315/189, 315/191, 315/307, 315/250
• US Class Current: 1/1
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/375 using buck topology
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/385 using flyback topology
• 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 device includes a first and a second gate circuit having a first input to which a high frequency square wave signal generated from a high frequency oscillation circuit is inputted and a second input to which a first low frequency square wave signal is inputted; and a second gate circuit having a first input to which the high frequency square wave signal is inputted and a second input to which a second low frequency square wave signal is inputted. Each of the first and the second low frequency square wave signal has a frequency lower than that of the high frequency square wave signal, and the first and the second low frequency square wave signal determine whether the high frequency square wave signal is supplied, as on/off switching signals, to the first and the second switching power supply circuit, respectively.

Claims

1. A lighting device comprising:

a first switching power supply circuit and a second switching power supply circuit which are connected in parallel to an input DC power supply to drive a first semiconductor light emitting element emitting a first light having a first color temperature and a second semiconductor light emitting element emitting a second light having a second color temperature which is different from the first color temperature;

a high frequency oscillation circuit which generates a high frequency square wave signal serving as an on/off switching signal of each of the first switching power supply circuit and the second switching power supply circuit;

a low frequency oscillation circuit which generates a first low frequency square wave signal and a second low frequency square wave signal;

a first gate circuit connected to the first switching power supply circuit having a first input to which the high frequency square wave signal is inputted and a second input to which the first low frequency square wave signal is inputted; and

a second gate circuit connected to the second switching power supply circuit having a first input to which the high frequency square wave signal is inputted and a second input to which the second low frequency square wave signal is inputted,

wherein each of the first low frequency square wave signal and the second low frequency square wave signal has a frequency lower than that of the high frequency square wave signal,

wherein the first gate circuit and the second gate circuit determine whether the high frequency square wave signal is supplied as the on/off switching signal to the first switching power supply circuit and the second switching power supply circuit based on the first low frequency square wave signal and the second low frequency square wave signal, respectively,

wherein on/off duties of the first low frequency square wave signal and the second low frequency square wave signal are complementarily changed such that a color temperature of a mixed light of the first light and the second light is varied, and

wherein a brightness of each of the first semiconductor light emitting element and the second semiconductor light emitting element is changed by adjusting an on/off duty of the high frequency square wave signal.

2. The lighting device of claim 1, wherein the lighting device includes an integrated circuit in which six logic circuits are embedded in one chip, and

wherein two of the logic circuits serve as the first gate circuit and the second gate circuit, and the other logic circuits serve as the low frequency oscillation circuit and the high frequency oscillation circuit.

3. An illumination apparatus comprising:

a first semiconductor light emitting element emitting a first light having a first color temperature;

a second semiconductor light emitting element emitting a second light having a second color temperature which is different from the first color temperature; and

a lighting device configured to drive the first semiconductor light emitting element and the second semiconductor light emitting element,

wherein the lighting device includes a first switching power supply circuit and a second switching power supply circuit which are connected in parallel to an input DC power supply to drive the first semiconductor light emitting element and the second semiconductor light emitting element;

a high frequency oscillation circuit which generates a high frequency square wave signal serving as an on/off switching signal of each of the first switching power supply circuit and the second switching power supply circuit;

a low frequency oscillation circuit which generates a first low frequency square wave signal and a second low frequency square wave signal;

a first gate circuit connected to the first switching power supply circuit having a first input to which the high frequency square wave signal is inputted and a second input to which the first low frequency square wave signal is inputted; and

a second gate circuit connected to the second switching power supply circuit having a first input to which the high frequency square wave signal is inputted and a second input to which the second low frequency square wave signal is inputted,

wherein each of the first low frequency square wave signal and the second low frequency square wave signal has a frequency lower than that of the high frequency square wave signal,

wherein the first gate circuit and the second gate circuit determine whether the high frequency square wave signal is supplied as the on/off switching signal to the first switching power supply circuit and the second switching power supply circuit based on the first low frequency square wave signal and the second low frequency square wave signal, respectively,

wherein on/off duties of the first low frequency square wave signal and the second low frequency square wave signal are complementarily changed such that a color temperature of a mixed light of the first light and the second light is varied, and

wherein a brightness of each of the first semiconductor light emitting element and the second semiconductor light emitting element is changed by adjusting an on/off duty of the high frequency square wave signal.

4. The illumination apparatus of claim 3, wherein the lighting device includes an integrated circuit in which six logic circuits are embedded in one chip, and

wherein two of the logic circuits serve as the first gate circuit and the second gate circuit, and the other logic circuits serve as the low frequency oscillation circuit and the high frequency oscillation circuit.