HCPL-7840-300E (BROADCOM LIMITED)

The HCPL-7840-300E is an Isolation Amplifier designed for current sensing in electronic motor drives. In a typical implementation, motor currents flow through an external resistor and the resulting analogue voltage drop is sensed by this. A differential output voltage is created on the other side of this 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 recommended application circuit. Since common-mode voltage swings of several hundred volts in tens of nanoseconds are common in modern switching inverter motor drives, this was designed to ignore very high common mode transient slew rates (of at least 10kV/µs).