Broadcom Inc. ACPL-785J Isolation Amplifier with Short Circuit and Overload Detection ACPL-785J-000E

The ACPL-785J isolation amplifier is designed for current sensing in electronic motor drives. In a typical implementation, motor currents flow through an external resistor and the resulting analog voltage drop is sensed by the ACPL-785J. A larger analog output voltage is created on the other side of the ACPL-785J’s optical isolation barrier. The output voltage is proportional to the motor current and can be connected directly to a single-supply A/D converter. A digital over-range output (/FAULT) and an analog rectified output (ABSVAL) are also provided. The wire OR-able over-range output (/FAULT) is useful for quick detection of short circuit conditions on any of the motor phases. The wire-OR-able rectified output (ABSVAL), simplifies measure-ment of motor load since it performs polyphase rectification. Since the common-mode voltage swings several hundred volts in tens of nanoseconds in modern electronic motor drives, the ACPL-785J was designed to ignore very high common-mode transient slew rates (10 kV/μs).