The UCC27321-Q1 and UCC27322-Q1 drivers serve as an interface between low-power controllers (discrete controllers, DSPs, MCUs, or microprocessors) and power MOSFETs. High-frequency power supplies often require high-speed, high-current drivers such as the UCC2732x-Q1 family. A leading application provides a high-power buffer stage between the PWM output of the control device and the gates of the primary power MOSFET or IGBT switching devices. In other cases, the device drives the power device gates through a drive transformer. Synchronous rectification supplies also have the need to drive multiple devices simultaneously, which can present an extremely large load to the control circuitry.

The inverting driver (UCC27321-Q1) is useful for generating inverted gate-drive signals from controllers that have outputs of the opposite polarity. For example, this driver can provide a gate signal for ground-referenced, N-channel synchronous rectifier MOSFETs in buck derived converters. This driver can also be used for generating a gate-drive signal for a P-channel MOSFET from a controller that is designed for N-channel applications.

MOSFET gate drivers are generally used when it is not feasible to have the primary PWM regulator device directly drive the switching devices for one or more reasons. The PWM device may not have the brute drive capability required for the intended switching MOSFET, limiting the switching performance in the application. In other cases, there may be a desire to minimize the effect of high-frequency switching noise by placing the high-current driver physically close to the load. Also, newer devices that target the highest operating frequencies may not incorporate onboard gate drivers at all. Their PWM outputs are only intended to drive the high-impedance input to a driver such as the UCC2732x-Q1. Finally, the control device may be under thermal stress due to power dissipation and an external driver can help by moving the heat from the controller to an external package.