7.3.1.4 DRV (Gate Drive)

The DRV pin is connected to the MOSFET gate pin, usually through a series resistor. The DRV provides a gate drive signal which is clamped to 10-V internally. During turn-on the driver applies a typical 30-mA current source out of the DRV pin. When the DRV voltage rises to above 9 V the output current is reduced to about 100 µA. This current brings the DRV voltage to the 10-V clamp level, or to VDD, whichever is less. The 30-mA current provides adequate turn-on speed while automatically limiting noise generated at turn-on by the MOSFET drain dv/dt and by the leading edge turn-on current spike. The gate drive turn-off current is internally limited to about 400 mA when DRV is above about 4 V. At lower DRV voltages the current will reduce, eventually being limited by the low-side on resistance, R_DS(on). The drain turn-on and turn-off dv/dt can be further impacted by adding external resistor in series with DRV pin. The drain current resonances can be damped with a small series gate resistor, generally less than a 1 Ω.