Methods and circuits for generating output voltage to LED strings

A circuit for generating an output voltage to a top node of a plurality of LED strings. The circuit includes an inductor having a load current flowing therethrough and a switching transistor responsive to a switching control signal. An integrator generates a compensation voltage responsive to a volt...

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Bibliographische Detailangaben
Hauptverfasser: ARCHIBALD, NICHOLAS IAN, WARRINGTON, ALLAN RICHARD
Format: Patent
Sprache:chi ; eng
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Beschreibung
Zusammenfassung:A circuit for generating an output voltage to a top node of a plurality of LED strings. The circuit includes an inductor having a load current flowing therethrough and a switching transistor responsive to a switching control signal. An integrator generates a compensation voltage responsive to a voltage at a bottom node of the LED string and a reference voltage. Circuitry for combining an offset with the compensation voltage is responsive to the compensation voltage and the load current through the inductor. The offset is generated only during a step load change of the load current and substantially reduces voltage transients from the compensation voltage and the output voltage. A summation circuit sums the compensation voltage including the offset with at least the voltage at the bottom node of the LED string to generate a first control signal. A latch generates the switching control signal responsive to the first control signal and a leading edge blanking signal.