US 2017/0325305 A1Published application

Lighting device

AssigneeRohm Co., Ltd.

InventorsNoboru Takizawa, Masaaki Nakayama

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Abstract

A lighting device includes light emitting element groups (HSB) including a light emitting element group (HS2) that emits light when being applied with a voltage (VH2), and a light emitting element group (HS12) that emits light when being applied with a voltage (VH12) higher than VH2, the light emitting element groups (HSB) emitting light when being applied with a voltage equal to or higher than a voltage (VHa); an IC1 including a light emission control unit (HC1) arranged to cause light emission of a light emitting element group (HS) if a voltage (Vk) is higher than VHa, and to stop the light emission if Vk is lower than the same; and an IC2 including a light emission control unit (HC2) arranged to cause light emission of a group (HSa) if Vk is higher than VHa, and to turn off the group (HSa) if Vk is lower than the same.

Claims24

Dependent claims

A lighting device comprising:

a power supply circuit arranged to supply a drive voltage;
light emitting element groups including a first light emitting element group having a plurality of first light emitting elements connected in series, arranged to emit light by a first light emission current flowing when being applied with a first light emission voltage based on the drive voltage, at a first light emission reference voltage or higher, and a second light emitting element group having a plurality of a second light emitting elements connected in series, arranged to emit light by a second light emission current flowing when being applied with a second light emission voltage based on the drive voltage, at a second light emission reference voltage higher than the first light emission reference voltage, the light emitting element groups emitting light when being applied with a light emission voltage equal to or higher than a light emission reference voltage based on the second light emission reference voltage;
a first semiconductor chip including a first light emission control unit arranged to detect a magnitude relationship between the drive voltage and the light emission reference voltage, to perform light emission control to cause light emission of the light emitting element group if the drive voltage is higher than the light emission reference voltage, and to perform light emission stop control to stop light emission of the light emitting element group if the drive voltage is lower than the light emission reference voltage, the first semiconductor chip being connected to the first light emitting element group;
and
a second semiconductor chip including a second light emission control unit arranged to detect a magnitude relationship between the drive voltage and the light emission reference voltage, to perform light emission control to cause light emission of the light emitting element group if the drive voltage is higher than the light emission reference voltage, and to perform light emission stop control to stop light emission of the light emitting element group if the drive voltage is lower than the light emission reference voltage, the second semiconductor chip being connected to the first semiconductor chip and the second light emitting element group.

2 more elements

A lighting device comprising:

a power supply circuit arranged to supply a drive voltage;
light emitting element groups including a first light emitting element group having a plurality of first light emitting elements connected in series, arranged to emit light by a first light emission current flowing when being applied with a first light emission voltage based on the drive voltage, at a first light emission reference voltage or higher, and a second light emitting element group having a plurality of a second light emitting elements connected in series, arranged to emit light by a second light emission current flowing when being applied with a second light emission voltage based on the drive voltage, at a second light emission reference voltage higher than the first light emission reference voltage, the light emitting element groups emitting light when being applied with a light emission voltage equal to or higher than a light emission reference voltage based on the second light emission reference voltage;
and
a light emission control unit arranged to detect a magnitude relationship between the drive voltage and the light emission reference voltage, to perform light emission control to cause light emission of the light emitting element group if the drive voltage is higher than the light emission reference voltage, and to perform light emission stop control to stop light emission of the light emitting element group if the drive voltage is lower than the light emission reference voltage.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 15/535,114Filed 4 Nov 2015
Priority: JP 2014-25177012 Dec 2014
Published: 9 Nov 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

H05B 45/46
With an active control inside an LED matrix: having LEDs disposed in parallel lines
H05B 45/10
Circuit arrangements for operating light-emitting diodes [LED]: controlling the intensity of the light
H05B 45/3725
Converter circuits: switched mode power supply [SMPS]
H02M 1/0067
Details of apparatus for conversion: converter structures employing plural converter units, other than for parallel operation of the units on a…