PX3511B

Description

The PX3511A and PX3511B are high frequency MOSFET drivers specifically designed to drive upper and lower power N-Channel MOSFETs in a synchronous rectified buck converter topology. These drivers combined with the ISL6595 Digital Multi-Phase Buck PWM controller and N-Channel MOSFETs form a complete core-voltage regulator solution for advanced microprocessors. The PX3511A drives the upper gate to 12V, while the lower gate can be independently driven over a range from 5V to 12V. The PX3511B drives both upper and lower gates over a range of 5V to 12V. This drive-voltage provides the flexibility necessary to optimize applications involving trade-offs between gate charge and conduction losses. An adaptive zero shoot-through protection is integrated to prevent both the upper and lower MOSFETs from conducting simultaneously and to minimize the dead time. These products add an overvoltage protection feature operational before VCC exceeds its turn-on threshold, at which the PHASE node is connected to the gate of the low side MOSFET (LGATE). The output voltage of the converter is then limited by the threshold of the low side MOSFET, which provides some protection to the microprocessor if the upper MOSFET(s) is shorted during initial start-up. These drivers also feature a three-state PWM input which, working together with Intersils multi-phase PWM controllers, prevents a negative transient on the output voltage when the output is shut down. This feature eliminates the Schottky diode that is used in some systems for protecting the load from reversed output voltage events.