GaN FETs get more attention: This time it's a low-side gate driver
Feb. 9, 2012
The LM5114 drives GaN FETs and MOSFETs in low-side applications, such as synchronous rectifiers and power factor converters.
Chip makers continue to get ready for Gallium-Nitride semiconductors and the higher efficiencies they can bring. Among the latest devices targeting GaN is a low-side gate driver for use with MOSFETs and enhancement mode GaN power field-effect transistors (FETs) in high-density power converters.
The LM5114 chip developed by Texas Instruments works in such low-side applications as synchronous rectifiers and power factor converters. The LM5114 provides independent sink and source outputs from a 5-V supply. It enables a 7.6-A peak turn-off current capability in high-power applications that use paralleled FETs. It is the increased pull-down strength that enables the chip to drive GaN FETs properly.
The independent source and sink outputs eliminate the need for a diode in the driver path and allows tight control of the rise and fall times. Other features of the device include matching delay times between inverting and non-inverting inputs that reduce dead time losses, a 12-nsec typical propagation delay that promotes high switching frequency while maintaining high efficiency.
Samples and an evaluation module of the new GaN FET driver: www.ti.com/lm5114-pr
