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

The UCC27524 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 drivers are disabled. Like the input pins, the enable pins are also based on a TTL and CMOS compatible, input-threshold logic that is independent of the supply voltage and are effectively controlled using logic signals from 3.3-V and 5-V microcontrollers. The UCC27524 devices also feature tight control of the enable-function threshold-voltage levels which eases system design considerations and ensures stable operation across temperature (refer to Typical Characteristics). 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 the ENx pins are left floating or Not Connected (N/C) for standard operation, where the enable feature is not needed. Essentially, this floating allows the UCC27524 device to be pin-to-pin compatible with TI’s previous generation of drivers (UCC27323, UCC27324, and UCC27325 respectively), where Pin 1 and Pin 8 are N/C pins. If the channel A and Channel B inputs and outputs are connected in parallel to increase the driver current capacity, ENA and ENB are connected and driven together.