5

10

15

20

0

4

8

12

16

20

Supply Voltage (V)

G008

2

4

6

8

10

0

4

8

12

16

20

Supply Voltage (V)

G009

UCC27517

UCC27516

www.ti.com

SLUSAY4C – MARCH 2012 – REVISED MAY 2013

TYPICAL CHARACTERISTICS (continued)

RISE TIME

FALL TIME

vs

vs

SUPPLY VOLTAGE

SUPPLY VOLTAGE

Figure 17.

Figure 18.

APPLICATION INFORMATION

Introduction

High-current gate-driver devices are required in switching power applications for a variety of reasons. In order to

effect fast switching of power devices and reduce associated switching power losses, a powerful gate driver is

employed between the PWM output of controllers and the gates of the power-semiconductor devices. Further,

gate drivers are indispensable when there are times that the PWM controller cannot directly drive the gates of

the switching devices. With advent of digital power, this situation is often encountered since 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. A

level-shifting circuitry is needed to boost the 3.3-V signal to the gate-drive voltage (such as 12 V) in order to fully

turn on the power device and minimize conduction losses. Because traditional buffer-drive circuits based on

NPN/PNP bipolar transistors in totem-pole arrangement, being emitter-follower configurations, lack level-shifting

capability, the circuits prove inadequate with digital power. Gate drivers effectively combine both the level-shifting

and buffer-drive functions. Gate drivers also find other needs such as minimizing the effect of high-frequency

switching noise by locating the high-current driver physically close to the power switch, driving gate-drive

transformers and controlling floating power-device gates, reducing power dissipation and thermal stress in

controllers by moving gate-charge power losses into itself. Finally, emerging wide-bandgap power-device

technologies, such as GaN based switches, which are capable of supporting very high switching frequency

operation, are driving very special requirements in terms of gate-drive capability. These requirements include

operation at low VDD voltages (5 V or lower), low propagation delays and availability in compact, low-inductance

packages with good thermal capability. In summary gate-driver devices are extremely important components in

switching power combining benefits of high-performance, low cost, component count and board space reduction

with a simplified system design.

Copyright © 2012–2013, Texas Instruments Incorporated

Submit Documentation Feedback

11

Product Folder Links: UCC27517 UCC27516