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US 2009/0021182 A1Published application
Led driver circuit
AssigneeKoninklijke Philips Electronics N.V.
InventorGeorg Sauerlaender
Life of this patent
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Abstract
The present invention relates to a low cost LED driver module comprising a switched-mode power supply (smps) having down-converting characteristics (11) which is controlled by a comparator (31). The comparator is hysteresis configured, which reduces ripple and transients in the LED current, and the module can be accomplished with inexpensive standard components.
Claims6
A LED driver circuit (1), comprising a supply voltage input terminal (3), a control input terminal (5) and first and second output terminals (7, 9) for connecting the driver circuit to at least one LED, wherein
- a switched-mode power supply (smps) having down-converting characteristics (11) is connected between the supply input terminal (3) and the first output terminal (7),
- the said converter (11) is controlled by a hysteresis configured comparator circuit (13) in order to regulate the LED current, and
- wherein switching levels of the comparator are set by a voltage reference (+Vref) received at a reference terminal (15).
Dependencies are inferred from the claim text.