Circuit for driving an led string
Assigneeams-OSRAM AG
InventorsCarlo FIOCCHI, Salvador Enrique HOSTALET LEITZKE
Life of this patent
Estimating the term…
Abstract
A driving circuit for driving a light-emitting diode, LED, string including a first LED and plurality of further LEDs coupled in series. The driving circuit includes a current comparator, the current comparator being configured to compare a supply current dependent on a supply voltage supplied by a voltage source with a reference current, and to generate a difference current. The driving circuit further includes a control element for controlling a current steered into one of the further LEDs. The control element includes a bypass element coupled in parallel to the further LED, the bypass element being controlled in dependence from the difference current.
Claims17
A driving circuit for driving a light-emitting diode, LED, string comprising a first LED and plurality of further LEDs coupled in series, the driving circuit comprising:
- a current comparator, the current comparator being configured to compare a supply current dependent on a supply voltage supplied by a voltage source with a reference current, and to generate a difference current;
- and
- a control element for controlling a current steered into one of the further LEDs,
- the control element comprising a bypass element coupled in parallel to the further LED, the bypass element being controlled in dependence from the difference current.
A driving circuit for driving a light-emitting diode, LED, string comprising a first LED and plurality of further LEDs coupled in series, the circuit comprising:
- a current comparator, the current comparator being configured to compare a supply current dependent on a supply voltage supplied by a voltage source with a reference current, and to generate a difference current;
- a bypass element, and
- circuit elements for mirroring the difference current to the bypass element,
- the bypass element being configured to subtract a bypass current depending on the difference current from an LED current Iled fed to a corresponding one of the further LEDs, the LED current Iled depending on the supply current.
Dependencies are inferred from the claim text.