The device provides an N-channel MOSFET driver that can source or sink a peak current of 1.5 A. The peak sourcing current is larger when supplying an external VCC that is higher than the 6.75-V VCC regulation target. During start-up, especially when the input voltage range is below the VCC regulation target, the VCC voltage must be sufficient to completely enhance the MOSFET. If the MOSFET drive voltage is lower than the MOSFET gate plateau voltage during start-up, the boost converter may not start up properly and it can stick at the maximum duty cycle in a high power dissipation state. This condition can be avoided by selecting a lower threshold N-channel MOSFET switch and setting the VSUPPLY(ON) greater than 6 to 7 V. Since the internal VCC regulator has a limited sourcing capability, the MOSFET gate charge should satisfy the following inequality.
An internal 1-MΩ resistor is connected between GATE and PGND to prevent a false turnon during shutdown. In boost topology, a switch node dV/dT must be limited during the 65-µs internal start-up delay to avoid a false turnon, which is caused by the coupling through CDG parasitic capacitance of the MOSFET.