1-MHz Bandwidth Current Sensor ICs with 3600-V(rms) Isolation

Allegro MicroSystems has added a new generation of high bandwidth current sensor ICs to their existing family of devices. The Allegro ACS732 and ACS733 current sensor ICs provide a compact, fast, and accurate solution for measuring high-frequency currents in dc-dc converters and other switching power applications.

These devices are the first 1MHz offerings from Allegro to offer 3600V(rms) galvanic isolation ratings. The current sensor ICs are Hall-effect-based and include user-configurable overcurrent fault detection.

These features make them ideally-suited for high-frequency transformer and current transformer replacement in applications running at high voltages.

The ACS732 and ACS733 are suitable for all markets, including automotive, industrial, commercial, and communications systems. They may be used in motor control, load detection and management, switch-mode power supplies, and overcurrent fault protection applications.

The block diagram below shows the internal architecture of the device. The temperature sensor allows Allegro to fine tune the zero amperage output voltage and sensitivity (signal path gain) over temperature.

Functional block diagram

The IC stores temperature compensation values in the EEPROM which provides a stable or high accuracy output signal over the full operating temperature range of the device. The devices are fully calibrated at the Allegro factory to provide a high accuracy solution over the entire operating temperature range.

The fully integrated wide body SOIC-16 package has a typical resistance of 1mΩ, providing low power loss and reduced bill of materials that allows for easy implementation. Applied current flowing through the copper conduction path generates a magnetic field that is sensed by the IC and converted to a proportional voltage.

Current is sensed differentially in order to reject external common-mode fields. The current-carrying pins (pins 1 through 8) are electrically isolated from the sensor leads (pins 9 through 16). This allows the devices to be used in high-side current sensing applications without the use of high-side differential amplifiers, isolators, or other costly isolation techniques.

The ACS732 and ACS733 are provided in a small, low profile, surface-mount SOIC-16 wide-body package. This package is lead (Pb) free, with 100% matt-tin leadframe plating (suffix -T).

Allegro MicroSystems Europe , Allegro MicroSystems, Inc.
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