12 January 2023
Richtek and EPC collaborate to create small 140W fast-charging solution
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 – and power management analog IC company Richtek Technology Corp of Hsinchu, Taiwan have announced the availability of a 4-switch bidirectional buck-boost controller reference design board that converts an input voltage of 12V–24V to a regulated 5V–20V output voltage and delivers up to 5A continuous current and 6.5A maximum current.
The combination of the new Richtek RT6190 controller with EPC2204 GaN FETs shrinks the solution size by more than 20% compared with traditional solutions for high-power-density applications, it is reckoned. The solution achieves greater than 98% efficiency for 20V and 12V output voltage and can operate without a heat-sink with maximum rise temperature below 15°C for 20V to 5V, and 55°C for 12V to 20V, at 5A continuous current.
The high power density makes this solution suitable for buck-boost converters with an input of 4V–36V and output of 3V–36V such as those used for 5V–36V battery chargers, battery stabilizers to 5V–36V and USB PD 3.1 charging (5V, 20V, 28V, 36V support). GaN FETs provide the fast switching, high efficiency and small size that can meet the stringent power density requirements of these leading-edge applications.
The reference design uses the EPC2204 100V enhancement-mode EPC GaN FET and the RT6190 4-switch buck-boost controller with integrated GaN drivers.
The RT6190 is a 4-switch bidirectional buck-boost controller with I2C interface using peak current mode control. The input voltage ranges between 4V and 36V and the output voltage is programmable between 3V and 36V and supports dynamic voltage scaling. The switching frequency reaches up to 1MHz for high power density and the device offers a power saving mode for high light load efficiency. Output current, voltage and soft start can be precisely programmed, and the device is fully protected and offers OCP, UVLO, OVP, OTP, cycle-by-cycle current limit, and PGOOD in a package measuring just 5mm by 5mm.
The EPC2204 is a 100V GaN FET with 6mΩ (maximum) RDS(on), 5.7nC QG, 0.8nC QGD, 1.8nC QGS and zero QRR in a super small 2.5mm x 1.5mm footprint and can deliver up to 29A continuous current and 125A peak current. The dynamic parameters allow very small switching losses at 500kHz–1MHz switching frequency, especially in hard-switching applications like buck-boost converters. Higher switching frequency enables a reduction in the inductor value, size and DC resistance (DCR) and in the capacitor count for less losses and higher power density.
“GaN FETs are required to achieve the maximum power density for DC–DC converters,” notes EPC’s CEO Alex Lidow. “We are delighted to work with Richtek 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 Richtek Device’s RT6190 is designed to fully exploit the high performance of EPC’s eGaN FETs for high-power-density solutions,” says Eason Chen, senior application marketing manager at Richtek, “The RT6190 offers higher switching frequency and integrates all protection features and functionality required for a 4-switch buck-boost controller for battery chargers and battery management/stabilizers to a fixed voltage, very common for consumer USB applications for PC and smart-phone, e-bike, e-scooter, battery-operated appliances and power tools, medical, industrial and solar applications. With these new controllers, customers can take advantage of the very fast switching of GaN for the highest power density.”
Both the Richtek RT6190 and the EPC2204 are in mass production now.