ANALOG DEVICES DC839A

DC839A demonstration circuit is a triple input ideal diode based PowerPath circuit featuring the LTC4413 dual Ideal diode controller with dual integrated MOSFETs. The circuit allows one of 3 sources to become the primary power source. Under certain circumstance, current sharing is possible among all power sources at any given time. However, only the BAT and USB inputs can share current equally given identical sources. Furthermore, only the BAT and USB power inputs are protected from reverse current flow. Wall input FET Q1 is not driven as an Ideal diode. Careful PCB layout in terms of heat sinking is critical to obtaining maximum circuit current. Q1 has no short circuit or thermal overload protection and care must be taken to not destroy the MOSFET. The maximum continuous current in free air room. The LTC4413 has weak internal pull-downs that allow BAT and USB inputs to be on by default with no connections to the ENBA and ENBB control inputs.