Synchronous Rectified Buck MOSFET Drivers

The ISL6625A is a high frequency MOSFET driver designed to drive upper and lower power N-Channel MOSFETs in a synchronous rectified buck converter topology. In ISL6625A, the upper and lower gates are both driven to an externally applied voltage. This provides the capability to optimize applications involving trade-offs between gate charge and conduction losses. An advanced adaptive shoot-through protection is integrated to prevent both the upper and lower MOSFETs from conducting simultaneously and to minimize dead time. The ISL6625A has a 10kΩ integrated high-side gate-to-source resistor to prevent self turn-on due to high input bus dV/dt. This driver also has an overvoltage protection feature, which is operational while VCC is below the POR threshold. The PHASE node is connected to the gate of the low-side MOSFET (LGATE) via a 30kΩ resistor, limiting the output voltage of the converter close to the gate threshold of the low-side MOSFET. This is dependent on the current being shunted, which provides some protection to the load should the upper MOSFET(s) become shorted.