Forward eSign Formula with airSlate SignNow

Forward esign formula

hello my name is kirk matthews i'm a senior applications engineer at linear technology today i'm going to talk about the ltc 3765 ltc 3766 synchronous forward converter chipset for use in high efficiency isolated dc to dc converters and battery chargers we'll learn how this product makes it easier to design a high performance and reliable ford converter for power levels ranging from 25 watts to over one kilowatt a ford converter is very similar to a buck converter each has an output inductor capacitor and synchronous switch the top switch in a buck converter is replaced by the ford converter's primary and forward switches diodes could be used in place of the forward and synchronous switches but switches make it more efficient on the forward converter a transformer provides isolation between grounds and allows the output voltage to be less than or greater than the input voltage the transform returns ratio is adjusted to optimize the duty cycle for example when stepping down from 100 to 1 volt with a buck converter the duty cycle would be one percent whereas a forward could operate at 20 percent or higher again this means higher efficiency every transformer must have balance positive and negative voltage applied to it if a transformer were ideal this wouldn't matter but a real transformer can be thought of as an ideal transformer with an additional magnetizing inductance across the primary when voltage is applied to the transformer the current and the magnetizing inductance will either ramp up or ramp down any imbalance in the transformer voltage will cause the magnetizing current to walk up or down towards saturation a saturated transformer behaves like a short circuit which can cause the power supply to fail activeclamp reset uses an additional capacitor and switch to apply a reset voltage during the converter's off time keeping the magnetizing current centered around zero now let's go into the lab and see an active clamp forward in action this is an 18 to 72 volt input to 12 volt 12 and a half amp output demo board powered from a bench supply the upper trace is the transformer magnetizing current and the lower trace is the primary drain voltage as i vary the input voltage the duty cycle and reset voltage change but the magnetizing current remains nicely centered around zero next i will use a mosfet and pulse generator to apply a 0 to 10 amp load step to the 12 volt output the magnetizing current temporarily increases then decreases to adjust the reset capacitor's voltage active clamp reset has some important advantages and challenges the reset capacitor applies the lowest possible reset voltage allowing the use of lower voltage mosfets which maximizes the efficiency however the voltage on the reset capacitor must change with duty cycle and if the duty cycle changes too quickly the capacitor's voltage may not be able to keep up resulting in saturation until now this basic issue has only been indirectly addressed...