HCPL-7840
Description
The HCPL-7840 isolation amplifier family was 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 HCPL-7840. A differential output voltage is created on the other side of the HCPL-7840 optical isolation barrier. This differential output voltage is proportional to the motor current and can be converted to a single-ended signal by using an op-amp as shown in the remended application circuit. Since mon-mode voltage swings of several hundred volts in tens of nanoseconds are mon in modern switching inverter motor drives, the HCPL-7840 was designed to ignore very high monmode transient slew rates (of at least 10 k V/μs).
The high CMR capability of the HCPL-7840 isolation amplifier provides the precision and stability needed to accurately monitor motor current in high noise motor control environ-ments, providing for smoother control (less “torque...
