GaN chip maker EPC has teamed up with Microchip on the design of a 300W DC-DC converter for 48V designs that measures just 33 x 23mm.
This 16th brick form factor combines the EPC2053 eGaN FET switches with Microchip’s dsPIC33CK digital signal controller. This two phase synchronous buck converter design gives an efficiency of 96 percent converting 48V down to 12V at 25A and a power density of 730 W/in 3. The GaN FETs have an RDS(on) resistance of 3.2 mΩ to reduce the converter size and conduction loss. Discrete GaN-specific gate drivers, the uP1966A from µPI semiconductor, are also selected. This eliminates the need for an anti-parallel diode and again reduces the losses. The 16-bit DSC has a maximum CPU speed of 100 MIPS, along with a pulse-width modulation (PWM) module that can be configured in high-resolution mode. This gives a 0.25ns resolution in duty cycle to reduce the dead time of the switching and boost the efficiency.
Additional phases can be added to the design to allow the input voltage to be adjusted from 8 V – 72 V and the output voltage from 3.3 V – 25 V.
The EPC9143 design is aimed at reducing the size of DC-DC converter bricks in data centres and telecoms designs, converting a nominal 48 V to a nominal 12 V distribution bus among other output voltages. The main trend has been towards higher power density given the form factor is fixed. A main application is high density 48V to 12V point-of-load (POL) converters, where a regulated 12V output voltage is required for devices such as commodity PCIe cards and storage.
These have also been targeted by new devices such as the single chip regulator from EmPower that can be embedded on the back of the controllers to distribute the 12V supply: CMOS SINGLE CHIP VOLTAGE REGULATOR TARGETS DATA CENTRES