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 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 V_SUPPLY(ON) greater than 6 to 7 V. Because the internal VCC regulator has a limited sourcing capability, the MOSFET gate charge should satisfy the following inequality.

Equation 18.

An internal 1-MΩ resistor is connected between GATE and GND to prevent a false turnon during shutdown. In boost topology, 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 C_DG parasitic capacitance of the MOSFET.