Low voltage or'ing circuits and methods with zero recovery time

摘要

Low voltage drop ORing circuits with zero recovery time and reverse current protection. In use, a MOSFET is coupled between a power supply and a load in a multiple power supply, single load system, or between a power supply and a load in a single power supply, multiple load system, or in both locations in multiple power supply, multiple load systems. A controller senses the current through the MOSFET, and turns the MOSFET off when the current falls below a predetermined threshold current. This allows time for circuit delays and the discharge of the gate of the MOSFET to turn the MOSFET off before the current through the MOSFET car reverse. Turn-on of the MOSFET when the current exceeds the threshold may be purposely slowed to avoid current spikes. Addition of another MOSFET controlled by the controller adds a hot swap capability and the control of the V_C slew rate. Various other features and embodiments are disclosed, including various current sensing techniques and circuits using transistors other than MOSFETs.