For the LM74700-Q1 to operate in full conduction mode the gate driver must be enabled as described in the Gate Driver section and the current from source to drain of the external MOSFET must be large enough to result in an ANODE to CATHODE voltage drop of greater than 50-mV typical. If these conditions are achieved the GATE pin is internally connected to the VCAP pin resulting in the GATE to ANODE voltage being approximately the same as the VCAP to ANODE voltage. By connecting VCAP to GATE the external MOSFET's RDS(ON) is minimized reducing the power loss of the external MOSFET when forward currents are large.
20V输入的仿真电路图