AUXILIARY TURN-ON MECHANISMS FOR REDUCING CONDUCTION LOSS IN BODY-DIODE OF LOW SIDE MOSFET OF COUPLED-INDUCTOR DC-DC CONVERTER
First Claim
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1. A DC-DC converter comprising:
- a plurality of power switching stages, each of which includes a plurality of output power switches having current flow paths therethrough coupled through respective mutually-coupled output inductors to an output node; and
a controller that is operative to apply primary switching signals to power switches of at least one of said power switching stages for controlling times during which power switches thereof are conductive to provide current flow paths therethrough, said controller including logical functionality operative to monitor on/off stages of transistors comprising said power switches and to provide auxiliary switching signals that are effective to turn-on a first power switch of a first output power switching stage, in association with induced current in the output inductor of said first output power switching stage resulting from current flow through a mutually coupled inductor of a second output power switching stage, wherein said induced current is prevented from flowing through a body-diode of said first power switch of said first output power switching stages.
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Abstract
Conduction loss in the body-diode of a low side MOSFET of a power switching stage of one phase of a coupled-inductor, multi-phase DC-DC converter circuit, associated with current flow in the output inductor of that one phase that is induced by current flow in a mutually coupled output inductor of another phase, during normal switching of that other stage, is effectively prevented by applying auxiliary MOSFET turn-on signals, that coincide with the duration of the induced current, to that low side MOSFET, so that the induced current will flow through the turned-on low side MOSFET itself, thereby by-passing its body-diode.
7 Citations
16 Claims
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1. A DC-DC converter comprising:
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a plurality of power switching stages, each of which includes a plurality of output power switches having current flow paths therethrough coupled through respective mutually-coupled output inductors to an output node; and a controller that is operative to apply primary switching signals to power switches of at least one of said power switching stages for controlling times during which power switches thereof are conductive to provide current flow paths therethrough, said controller including logical functionality operative to monitor on/off stages of transistors comprising said power switches and to provide auxiliary switching signals that are effective to turn-on a first power switch of a first output power switching stage, in association with induced current in the output inductor of said first output power switching stage resulting from current flow through a mutually coupled inductor of a second output power switching stage, wherein said induced current is prevented from flowing through a body-diode of said first power switch of said first output power switching stages. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a DC-DC converter having a plurality of power switching stages, each of which includes a plurality of output power switches having current flow paths therethrough coupled through a respective output inductor to an output node, and wherein multiple ones of said output inductors are mutually coupled to one another, so that current through a first output inductor induces current in a second output inductor, and a controller that is operative to apply primary switching signals to power switches of at least one of said output power switching stages for controlling times during which said power switches are conductive to provide current flow paths therethrough, the improvement wherein:
said controller is operative to generate auxiliary switching signals that are effective to turn-on a first power switch of a first output power switching stage, in association with induced current in the output inductor of said first output power switching stage resulting from current flow through a mutually coupled inductor of a second output power switching stage, wherein said induced current is prevented from flowing through a body-diode of said first power switch of said first output power switching stages. - View Dependent Claims (8, 9, 10, 11)
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12. A method of controlling the operation of a DC-DC converter having a plurality of power switching stages, each of which includes a plurality of output power switches having current flow paths therethrough coupled through a respective output inductor to an output node, and wherein multiple ones of said output inductors are mutually coupled to one another, so that current through a first output inductor induces current in a second output inductor, said method comprising the steps of:
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(a) applying primary switching signals to power switches of at least one of said output power switching stages so as to control times during which said power switches are conductive to provide current flow paths therethrough; and (b) generating, in association with induced current in the output inductor of said first output power switching stage resulting from current flow through a mutually coupled inductor of a second output power switching stage, auxiliary switching signals that are effective to turn-on a first power switch of a first output power switching stage, wherein said induced current is prevented from flowing through a body-diode of said first power switch of said first output power switching stages. - View Dependent Claims (13, 14, 15, 16)
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Specification