Optocoupler Improves System Efficiency in Industrial Designs

System design engineers for industrial applications, such as motor control inverter applications and high performance power systems, are looking for highly integrated gate driving and protection features in a single IC package to simplify design and improve efficiency. The newly-developed FOD8332 from Fairchild Semiconductor is a 2.5A output current IGBT/MOSFET drive optocoupler. The device's insulation working voltage rating (VIORM) of 1,414V is 13 percent higher than previous devices, permitting the device to directly drive 1200V IGBTs. Common Mode Transient Immunity (CMTI) is more than 100 percent better than competitive solutions, while Dynamic Power Consumption per cycle (ESW) during switching is 50 percent less than the competition.

These high voltage parts allow systems of a given power rating to operate at higher voltages and lower currents where the noise filtering becomes less lossy resulting in higher efficiency inverters. The FOD8332 integrates critical protection features necessary for preventing fault conditions that lead to destructive thermal runaway of IGBTs. It reduces design complexity as most protection features are built-in, eliminating the need for the board designer to specify additional components. Target applications include isolated IGBT and power MOSFET gate drives in renewable energy, solar and wind inverter systems, ac and brushless dc motor drives, industrial inverters, uninterruptible power supplies, and induction heating systems.

The device utilizes Fairchild’s proprietary Optoplanar® coplanar packaging technology and optimized IC design to achieve high insulation voltage and high noise immunity, characterized by high common mode rejection. The device is housed in a wide body 16-pin small outline plastic package which delivers high isolation performance in a compact package.

“Fairchild delivers a unique combination of power devices, design expertise and manufacturing experience to its customers, allowing them to power amazing electronic products,” said John Constantino, Director for Isolation and Optoelectronics at Fairchild. “The FOD8332 was developed after customer input and incorporates several features that specifically address the critical challenges they faced. This is part of our customer-centric focus and our goal of being the go-to source for innovative power management solutions.”

Key features include: Input LED drive facilitates receiving digitally-encoded signals from pwm output; Optically-isolated fault-sensing feedback; active Miller Clamp to shut off IGBT during high dv/dt without negative supply voltage; High noise immunity characterized by common mode rejection – 35 kV/μs minimum, VCM = 1500 VPEAK; 2.5A-peak output current driving capability for medium-power IGBT; P-channel MOSFETs at output stage enable output voltage swing close to supply rail (rail-to-rail output); Wide supply voltage range of 15V to 30V; UL1577, 4,243 V RMS for 1 minute; DIN-EN/IEC60747-5-5 (Pending); 1,414 VPEAK working insulation voltage; 8,000 VPEAK transient isolation voltage rating; and 8 mm creepage and clearance distances.