2 May 2023
Reference design uses new Analog Devices controller optimized to drive EPC GaN FETs
Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA – which makes enhancement-mode gallium nitride on silicon (eGaN) power field-effect transistors (FETs) and integrated circuits for power management applications – has announced the availability of the EPC9158, a dual-output synchronous buck converter reference design board operating at 500kHz switching frequency that converts an input voltage of 48–54V to a regulated 12V output and delivers up to 25A per phase or 50A total continuous current. The combination of the new LTC7890 synchronous GaN buck controller from Analog Devices Inc of Wilmington, MA, USA with GaN FETs from EPC enables a highly efficient solution in a small footprint for high-power-density applications. The solution achieves 96.5% efficient at 48V to 12V and 50A continuous current.
The high power density makes this solution suitable for computing, industrial, consumer and telecom power systems requiring small size and high efficiency. eGaN FETs provide the fast switching, high efficiency and small size that can meet the stringent power density requirements of these leading-edge applications, says EPC.
The EPC9158 reference design uses the EPC2218 100V enhancement-mode GaN FET and the LTC7890 two-phase analog buck controller with integrated GaN drivers.
The LTC7890 100V low-Iq, dual, 2-phase synchronous step-down controller is fully optimized to drive EPC GaN FETs and integrates a half-bridge driver and smart bootstrap diode. It offers optimized near-zero dead-time or programmable dead-time and programmable switching frequency up to 3MHz. The quiescent current of 5μA (VIN = 48V, VOUT = 5V, CH1 only) enables very low standby power consumption and excellent light load efficiency.
The EPC2218 is a 100V GaN FET with 3.2mΩ maximum RDS(on), 10.5nC QG, 1.5nC QGD, 46nC QOSS and zero QRR in a small 3.5mm x 1.95mm footprint and can deliver up to 60A continuous current and 231A peak current. The dynamic parameters allow very small switching losses at 500kHz switching frequency.
The efficiency of the EPC9158 is greater than 96.5% for 12V output and 48V input. In addition to light load operating mode and adjustable dead-time, the board offers UVLO, over-current protection, and power good output.
“GaN FETs are required to achieve the maxim power density for DC–DC converters,” notes CEO Alex Lidow. “We are delighted to work with Analog Devices to combine the benefits of their advanced controllers with the performance of GaN to provide customers with the highest-power-density and low-component-count solution that increases the efficiency, increases power density, and reduces system cost,” he adds.
“The Analog Device’s LTC7890 is designed to fully exploit the high performance of EPC’s eGaN FETs for high-power-density solutions,” says Tae Han, senior product marketing manager at Analog Devices, “The LTC7890 offers higher switching frequency and optimized dead-time that competes well above the current solution in the market while operating in very low power consumption,” he adds. “With these new controllers, customers can take advantage of the very fast switching of GaN for the highest power density.”
The EPC9158 demonstration board from EPC is priced $480 each and is available for immediate delivery from distributor Digi-Key Corp.