News and New Products

Linear optocoupler lets you look but not touch

By Bill Schweber -- EDN, 9/25/2003

Many power-supply and motor-control designs need to sense current and maintain galvanic isolation between the voltage-dropping sense resistor and the rest of the circuit. The HCPL-7510 and similar HCPL-7520 single-ended linear optocouplers from Agilent Technologies provide sensing along with low power consumption, targeting electronic-motor-drive uses (Picture). The optocouplers sense the voltage drop through the external sense resistor and develop a proportional output voltage on the other side of the optical isolation barrier. Agilent’s products use internal sigma-delta A/D conversion to ensure linear current sensing.

Common-mode rejection is 15 kV/μsec at 1000V common-mode levels, 100-kHz bandwidth, 0.06% nonlinearity, and ±3% gain tolerance for the HCPL-7510 and ±5% for the HCPL-7520. The eight-pin DIP devices meet UL safety standards, and Canadian CSA and European DIN certification are pending. The devices sell for $2.31 and $2.13 (5000) for the ±3 and ±5% versions, respectively.

Agilent Technologies, www.agilent.com/view/optocouplers.