ROHM has announced the BD9G341AEFJ, a DC/DC converter IC incorporating a high-voltage (80 V) MOSFET. The high voltage rating of 80 V is in the top class of the industry for a non-isolated DC/DC converter IC with an internal power transistor, and positions this device as the highest-voltage model in ROHM's lineup of DC/DC converter products. With increasing use in telecom-related areas, industrial equipment, and more recently in applications employing battery stacks, demand for high-voltage DC/DC converters continues to rise. However, only a limited number of manufacturers are supplying DC/DC converter ICs with rated voltages above 60 V, and a variety of such devices is not currently available.
The BD9G341AEFJ is a DC/DC converter IC incorporating an 80 V/3.5 A-rated N-channel MOSFET as a power switch, and by adding only a small number of external components, can be used to construct a high-performance, high-voltage DC/DC converter. In general, high-voltage DC/DC converters often employ a circuit configuration in which a high-voltage MOSFET is added externally to achieve a high voltage rating. The BD9G341AEFJ integrates the high-voltage MOSFET, which requires advanced circuit integration technology, in order to reduce the required footprint and simplify the design. In addition, the on-resistance of the internal MOSFET is a low 150 mΩ, contributing to improved efficiency.
The conversion method used in the BD9G341AEFJ is a step-down method called diode rectification or asynchronous rectification. A high-side MOSFET is incorporated, but the catch diode is external. The catch diode is a Schottky barrier diode, and must have a high voltage rating to be able to tolerate the maximum voltage input to the circuit. ROHM also provides various diodes that are well-suited to switching power supplies, and can supply Schottky barrier diodes required by the BD9G341AEFJ.
Major features of the device and a typical circuit example are shown below. By adopting current mode control, phase compensation is made simple and fast transient response is obtained. The switching frequency can be set in the range from 50 kHz to 750 kHz, so that size and efficiency can be optimized. A further feature is the provision of nearly all the protection functions that might be required.
- ・Integrated 80 V/3.5 A rating,
Ron 150 mΩ Nch MOSFET
- ・Maximum output current: 3 A
- ・Input voltage range: 12 V to 76 V
- ・Output voltage range: 1.0 V to input voltage
- ・Switching frequency (adjustable): 50 kHz to 750 kHz
- ・Fast transient response in current mode
- ・Reference voltage: 1.0 V±1.5 % （at 25℃）,
±2% （over temperature）
- ・Precision EN threshold: ±3 %
- ・Soft-start function
- ・Standby function
- ・Over current protection （OCP）, Under voltage lockout （UVLO）,
Thermal shutdown （TSD）, and Over voltage protection（OVP） provided
- ・Operating temperature: -40℃ to +85℃
- ・Package: HTSOP-J8 (4.9 mm x 6.0 mm x 1.0 mm）