Avago Technologies Limited (Avago) has launched a new series of competitively priced isolation amplifiers with short circuit and overload detection. The new Avago’s ACPL-785J isolation amplifiers allow direct measurement of motor phase currents in power inverters. Typical applications include inverter current sensing, motor phase and rail current sensing, switching power supply signal isolation, industrial A/D converters and general-purpose current sensing and monitoring.

The new amplifiers are based on optical insulation technology and sigma-delta modulation for signal processing.

Motor control power stages require a combination of current sensing and power device protection to achieve accurate fail-safe motor operation. These current sensors, which feedback the motor phase or rail current to the microcontroller, are typically optimized for accuracy to provide precise control. Once a fault condition has been detected, the power device circuitry shuts off the device to prevent destruction of the power device and load.

Avago’s ACPL-785J series of isolation amplifiers come in a compact small outline-16 (SO-16) package with a footprint that is 10.3 mm (L) by 10.2 mm (W) by 3.5 mm (H). The addition of the ACPL-785J to its existing HCPL-78xx family of isolation amplifiers will enable motor control designers to reduce the printed circuit board (PCB) size required for their designs. These new SO-16 packages are compliant to most industrial safety standards such as IEC/EN/DIN EN 60747-5-5, UL 1577 and CSA.

Features and Benefits

— Integrated over-current and overload detection.

— 1µV/degrees-C offset change vs. temperature.

— High CMR (25 kV/µs at VCM = 1000 V) to ignore high common-mode noise and provide smoother control.

— Compact auto-insertable SO-16 package saves PCB space.

— 20 kHz minimum bandwidth.

— Advanced Sigma-Delta A/D converter technology.