8.1 Overview

The UCC27712 consists of one ground-referenced channel (LO) and one floating channel (HO) which is designed for operating with bootstrap or isolated power supplies. The device features fast propagation delays and excellent delay matching between both channels. On the UCC27712, each channel is controlled by its respective input pins,

Developed with TI’s state of the art high-voltage technology, the device features robust drive with excellent noise and transient immunity including large negative voltage tolerance on its inputs, high dv/dt tolerance, and wide negative transient safe operating area (NTSOA) on the switch node (HS).

The UCC27712 includes protection features where the outputs are held low when the inputs are floating or when the minimum input pulse width specification is not met. Interlock and deadtime functions prevent both outputs from being turned on simultaneously. In addition, the device accepts a wide range bias supply range from 10 V ~ 20 V, and offers UVLO protection for both the VDD and HB bias supply.

High-current, gate-driver devices are required in switching power applications for a variety of reasons. In order to implement fast switching of power devices and reduce associated switching power losses, a powerful gate-driver device is employed between the PWM output of control devices and the gates of the power semiconductor devices. Further, gate-driver devices are indispensable when having the PWM controller device directly drive the gates of the switching devices is sometimes not feasible. In the case of digital power supply controllers, this situation is often encountered because the PWM signal from the digital controller is often a 3.3-V logic signal which is not capable of effectively turning on a power switch.

In bridge topologies, like hard-switch half bridge, hard-switch full bridge, half-bridge and full-bridge LLC, and phase-shift full bridge, the source and emitter pin of the top-side power MOSFET and IGBT switch is referenced to a node whose voltage changes dynamically; that is, not referenced to a fixed potential, so floating-driver devices are necessary in these topologies.

The UCC27712 is a high-side and low-side driver dedicated for offline AC-to-DC power supplies and inverters. The high side is a floating driver that can be biased effectively using a bootstrap circuit, and can handle up to 600-V. The driver can be used with 100% duty cycle as long as HB-HS can be above UVLO of the high side.

The device features industry best-in-class propagation delay and delay matching between both channels aimed at minimizing pulse width distortion in high-frequency switching applications. Each channel is controlled by its respective input pins (HI and LI), allowing independent flexibility to control on and off state of the output but does not allow the HO and LO outputs to be on at the same time. The UCC27712 includes an interlock feature which guarantees a 150ns dead time between the HO and LO outputs if the HI and LI inputs are complimentary. The UCC27712 includes protection features wherein the outputs are held low when inputs are floating or when the minimum input pulse width specification is not met. The driver inputs are CMOS and TTL compatible for easy interface to digital power controllers and analog controllers alike.