Hello,
We are doing a two transistor forward converter with LT1681.
VIN=48V; VOUT=-40V; FSW=250KHZ; POUT=160W.
The high side FET is driven by a bootstrap high side drive. The bootstrap capacitor stays charged up via a "bootstrap FET" (M3) which switches out of phase with the power-path FETs.
The problem is that the high side power path FET switchs ON just a few nanoseconds after the bootstrap FET has turned OFF. This is incredibly tight timing, i mean, if these FETs are ever both ON together then there would be serious shoot through current. All that prevents this is a few nanoseconds.
Do you believe, that the spacing between the switching transitions of these FETs is too close? and that in some parts, the timing will be poorer tolerance, and shoot through may occur?
LT1681 Datasheet
http://cds.linear.com/docs/en/datasheet/1681f.pdf
(LTspice simulation and schematic attached.)
We are doing a two transistor forward converter with LT1681.
VIN=48V; VOUT=-40V; FSW=250KHZ; POUT=160W.
The high side FET is driven by a bootstrap high side drive. The bootstrap capacitor stays charged up via a "bootstrap FET" (M3) which switches out of phase with the power-path FETs.
The problem is that the high side power path FET switchs ON just a few nanoseconds after the bootstrap FET has turned OFF. This is incredibly tight timing, i mean, if these FETs are ever both ON together then there would be serious shoot through current. All that prevents this is a few nanoseconds.
Do you believe, that the spacing between the switching transitions of these FETs is too close? and that in some parts, the timing will be poorer tolerance, and shoot through may occur?
LT1681 Datasheet
http://cds.linear.com/docs/en/datasheet/1681f.pdf
(LTspice simulation and schematic attached.)
