21 June 2011

Nat Semi launches first 100V half-bridge gate driver for E-mode GaN power FETs

National Semiconductor Corp of Santa Clara, CA, USA has made available samples of what is claimed to be the first 100V half-bridge gate driver optimized for use with enhancement-mode (E-mode) gallium nitride (GaN) power field-effect transistors (FETs) in high-voltage power converters. The new LM5113 is a highly integrated, high-side and low-side GaN FET driver integrated circuit (IC) that reduces component count by 75% and shrinks printed circuit board (PCB) area by up to 85% compared with discrete driver designs, the firm adds.

Designers of power bricks and communications infrastructure equipment require high power efficiency in the smallest form factor, Nat Semi says. Enhancement-mode GaN FETs enable new levels of efficiency and power density compared with standard silicon metal-oxide semiconductor field-effect transistors (MOSFETs) due to their low on-resistance (Rds(on)) and gate charge (Qg) as well as their ultra-small footprint, but driving them reliably presents significant new challenges. The LM5113 driver eliminates these challenges, it is claimed, enabling power designers to realize the benefits of GaN FETs in a variety of popular power topologies.

Meeting the stringent gate drive requirements of E-mode GaN FETs requires multiple discrete devices and significant circuit and PCB design effort. The fully integrated LM5113 driver greatly reduces circuit and PCB design effort and delivers what is claimed to be industry-best power density and efficiency.

“National’s LM5113 bridge driver helps designers unleash the performance of eGaN FETs by simplifying the design,” says Alex Lidow, co-founder & CEO of Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA, which makes E-mode GaN power FETs based on its proprietary gallium nitride on silicon (GaN-on-Si) technology for power management applications. “The LM5113 dramatically reduces component count, and paired with our eGaN FETs, enables a tremendous PCB area savings and higher level of power density versus equivalent MOSFET-based designs,” he adds.

Using proprietary technology, the LM5113 regulates the high-side floating bootstrap capacitor voltage at about 5.25V to optimally drive E-mode GaN power FETs without exceeding the maximum gate–source voltage rating. It also features independent sink and source outputs for flexibility of the turn-on strength with respect to the turn-off strength. A low-impedance pull-down path of 0.5Ω provides a fast, reliable turn-off mechanism for the low-threshold-voltage E-mode GaN power FETs, helping to maximize efficiency in high-frequency power supply designs.  

The LM5113 features an integrated high-side bootstrap diode, further minimizing PCB real estate. It also provides independent logic inputs for the high-side and low-side drivers, enabling flexibility for use in a variety of both isolated and non-isolated power supply topologies.

Offered in a 10-pin 4mm x 4mm LLP package and costing $1.65 each in quantities of 1000, production quantities of the LM5113 will be available in September.

Tags: E-mode GaN power FETs

Visit: www.national.com/pf/LM/LM5113.html