Guaranteed bootstrap hold-up circuit for buck high side switch

A buck regulator switching power supply ( 10 ) selectively enabling a low side device to effectively recharge a bootstrap capacitor (Cboot) during a high duty cycle of operation. The switching power supply ( 10 ) includes a gate driver ( 12 ) driving a gate of a high side FET (Q 1 ) responsive to a...

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Bibliographische Detailangaben
Hauptverfasser: FOWLER THOMAS LANE, DANIELS DAVID GENE, JOHNSON ALAN MICHAEL
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:A buck regulator switching power supply ( 10 ) selectively enabling a low side device to effectively recharge a bootstrap capacitor (Cboot) during a high duty cycle of operation. The switching power supply ( 10 ) includes a gate driver ( 12 ) driving a gate of a high side FET (Q 1 ) responsive to a controller circuit ( 14 ). Controller circuit ( 14 ) includes a controller ( 16 ) responsively controlled by a comparator ( 18 ). Comparator ( 18 ) senses the charge of the charging side of the bootstrap capacitor (Cboot) as compared to a voltage (Vref). The comparator ( 18 ) also responsively generates an output signal on an output line ( 20 ) as a function of the voltage at the phased output.