LED driver
AssigneeSignify Holding B.V.
InventorAndrew Ulrich Rutgers
Life of this patent
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Abstract
LED driver (1) comprising a switched-mode power converter (10) for providing power to an LED arrangement (100) connected across output terminals of the converter (10), and wherein the converter (10) comprises a number of energy storage elements (L, C) and a first semiconductor switch (Q1); a second semiconductor switch (Q2) connected in series with the LED arrangement (100); a control means (11) realized to generate a second control signal (G2) for the second semiconductor switch (Q2), such that a transition of the second control signal (G2) is delayed relative to a corresponding transition of a first control signal (G 1) for the first semiconductor switch (Q 1). The invention further describes a projection arrangement (2); and a method of driving an LED arrangement (100).
Claims15
A light emitting diode (LED) driver comprising:
- a switched-mode power converter for providing power to an LED arrangement connected across output terminals of the converter, and wherein the converter comprises a number of energy storage elements (L, C) and a first semiconductor switch (Q1);
- a second semiconductor switch (Q2) connected in series with the LED arrangement;
- a controller to generate a second control signal (G2) for the second semiconductor switch (Q2), such that a transition of the second control signal (G2) is delayed relative to a corresponding transition of a first control signal (G1) for the first semiconductor switch (Q1);
- wherein the energy storage elements (L, C) includes an inductor (L) and the controller generates a delay of a trailing edge transition of the second control signal (G2) as a function of a current level of the inductor (L).
A method of driving a light emitting diode (LED) arrangement, comprising the steps of:
- arranging a switched-mode power converter comprising at least a number of energy storage elements (L, C) and a first semiconductor switch (Q1) to provide power to the LED arrangement connected at the output of the converter;
- arranging a second semiconductor switch (Q2) in series with the LED arrangement;
- providing a control means to generate a second control signal (G2) for the second semiconductor switch (G2), such that a transition of the second control signal (G2) is delayed relative to a corresponding transition (G1) of a first control signal (G1) for the first semiconductor switch (Q1);
- and
- wherein the energy storage elements (L, C) comprise an inductor (L) and the step of providing the control means (11) comprising generating a delay of a trailing edge transition of the second control signal (G2) as a function of a current level of the inductor (L).
Dependencies are inferred from the claim text.