A control circuit of a DC/DC converter is provided for supplying a driving voltage to a light emitting element. A hysteresis comparator compares a detection voltage that corresponds to the output voltage of the DC/DC converter with two threshold voltages. If the detection voltage is smaller than the lower threshold voltage, the hysteresis comparator outputs a comparison signal at the low level. Otherwise, the comparison signal is set to the high level. The switching control unit uses the comparison signal as a reference. The switching control unit instructs the switching transistor of the DC/DC converter to perform the switching operation during a period when the comparison signal is at the low level. Otherwise, the switching operation is suspended. The control circuit inhibits light emission of the light emitting element during a period when the comparison signal is at the low level. Otherwise, the control circuit permits the light emission.

Claims

6 · 1 independent · depth 3

6 granted claims

›1.independentA light emitting apparatus comprising:na DC/DC converter including a switching transistor which allows step-up voltage operation to be controlled by p…+5

›2.↳ 1The light emitting apparatus according to claim 1, wherein light emission of the light emitting element is inhibited during a period when the comparis…d2

›3.↳ 1The light emitting apparatus according to claim 1, wherein said control circuit further comprises:na first voltage comparator which compares the volta…d2+1

›5.↳ 1The light emitting circuit according to claim 1, wherein said control circuit further comprises a transistor in which the comparison signal output fro…d2

›6.↳ 1The light emitting circuit according to claim 1, wherein said light emitting element comprises a xenon tube lamp,nand wherein the light emission state…d2

Classifications

4 codes

IPC · International Patent Classification

Section H — Electricity

H05B37/02

USPC · US Patent Classification

315/307315/209.R315/362

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Pendency

1.3 y

490 days filing → grant

Office actions

non-final + final

Responses

2 RCE

Examiner

Douglas W Owens

art unit 2821 · TC 2800

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Citations: 23 back · 0 forward

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1 priority documents

›Priority documents — 1

Type	Document	Date
related publication	US 20100270950 A1	28 Oct 2010

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