ADC Chipset Simplifies Motor Control

Optimized for measuring motor-phase currents in variable-speed, motor-drive control systems, the HCPL-7560 and HCPL-0872 optically-isolated, programmable, a/d converter chipset interfaces directly to microcontroller and DSP-based drive systems. The HCPL-7560 sigma-delta modulator allows direct measurement of current from less than 1A to 100A via a current-sensing resistor. It provides an isolation-mode transient immunity of 15 kV/ms. The HCPL-0872 digital interface IC is programmable, allowing tradeoffs between resolution and speed. These tradeoffs are achieved by programming the device to one of five available conversion modes. Additional programming features include a pre-trigger circuit that can reduce conversion time to 200 ns, an over-range detector that observes short circuits within 3 ms, offset calibration, and an adjustable threshold detector for non-short overload conditions. Both devices operate in temperatures from -40°C to +85°C. Prices for the HCPL-7560 and HCPL-0872 are $4.63 and $2.44 each/1,000, respectively. AGILENT TECHNOLOGIES INC., Palo Alto, CA. (800) 235-0312.