Renesas ISL784x4 family of MOSFET drivers

Renesas Electronics has announced the ISL784x4 family of automotive-grade 100 V, 4A half-bridge N-channel MOSFET drivers. The ISL78424 and ISL78444 feature single, tri-level PWM input for controlling both gate drivers, and the ISL78434 has dual independent inputs that separately control the high-side and low-side drivers.

The half-bridge N-MOSFET drivers complement the ISL78224 four-phase bidirectional controller, enabling it to provide up to 3 kW of power and greater than 95% efficiency in 12–48 V converters used in mild hybrid vehicles. The drivers are also suitable for 12–24 V bidirectional DC/DC converters, as well as other high-current buck or boost applications.

The drivers are designed to simplify driving high-current MOSFETs by offering independent sourcing and sinking MOSFET gate drive pins. This makes it easy for designers to use external gate resistors to tune the slew rate of the rising and falling DC/DC switch node transitions, thereby reducing electromagnetic interference. They also provide adaptive dead-time control to ensure break-before-make switching operations that prevent shoot-through current that would occur if both DC/DC converter switches were allowed to close simultaneously. The ISL78424 and ISL78434’s adaptive dead time function is able to sense at the gate of the MOSFETs, eliminating potential errors introduced by voltage drops across the external gate resistors controlling the switching node slew rate.

The drivers are suitable for high-current DC/DC applications, improving efficiency by delivering robust gate drive with 3 A peak sourcing current and 4 A peak sinking current. Strong gate drive allows them to rapidly switch high-current MOSFETs with large gate capacitance, which reduces switching losses. The half-bridge MOSFET drivers’ adaptive dead time control minimises excess dead time to reduce conduction losses and further increase DC/DC conversion efficiency.

The drivers offer voltage ratings that are suitable for 48 V automotive systems with the switching node tolerating 70 VDC and up to 86 V for infrequent transients. Similarly, the high-side driver’s bootstrap node can tolerate 86 VDC and up to 100 V during transients.