The enable function is an extremely beneficial feature in gate driver devices, especially for certain applications such as synchronous rectification where the driver outputs are disabled in light-load conditions to prevent negative current circulation and to improve light-load efficiency.

The UCC27444-Q1 device is equipped with independent enable pins (ENx) for exclusive control of each driver channel operation. The enable pins are based on a non-inverting configuration (active-high operation). Thus, when ENx pins are driven high, the drivers are enabled and when ENx pins are driven low, the driver outputs are disabled. Similar to the input pins, the enable pins are also based on a TTL compatible threshold logic that is independent of the supply voltage and are effectively controlled using logic signals from 3.3-V or 5-V controllers. The ENx pins are internally pulled up to VDD using pullup resistors, as a result of which the outputs of the device are enabled in the default state. Hence even if the ENx pins are left floating the driver output is enabled. Essentially, this floating allows the UCC27444-Q1 device to be pin-to-pin compatible with TI’s previous generation of drivers (UCC27324, UCC27424, UCC27524), where Pin 1 and Pin 8 are either ENx or N/C pins.