Small isolation amplifier technology for automobiles based on ACPL-782T-EEWORLD

Collect

The ACPL-782T is a small isolation amplifier used in electronic motor drive and battery system monitoring for voltage and current sensing. In a typical application, the motor current flows through an external resistor, and the resulting analog voltage drop is sensed by the ACPL-782T. On the other side of the ACPL-782T optical isolation barrier, a differential output voltage is generated. The differential output voltage is proportional to the motor current and can be converted to a single-ended signal using an optical amplifier used in the recommended application circuit. Since voltage swings of hundreds of volts in a few billionths of a second are common in modern switch-commutated motor drives, the ACPL-782T can ignore very high (at least 10kV/µs) common mode transient slew rates. The

high CMR performance of the ACPL-782T isolation amplifier gives it the accuracy and stability required to accurately monitor motor current and DC voltage rails in a noisy motor control environment, enabling smoother control (less torque ripple) in a variety of motor control applications.

The product can also be used in general-purpose analog signal isolation applications that require high accuracy, high stability, and high linearity in the same harsh noise environment. The ACPL-782T uses Σ-Δ analog-to-digital converter technology, chopper-stabilized amplifiers, and a fully differential circuit topology.

These features result in high isolation mode noise rejection and good offset, gain accuracy, and stability over time and temperature. The device is packaged in a small 8-pin industry-standard DIP package that meets worldwide safety standards.

Figure 1 ACPL-782T functional block diagram

Figure 2 ACPL-782T application circuit diagram

[page] ACPL-782T main features

• ±2% gain tolerance at 25℃

• 15kV/μs common mode rejection at VCM=1000V

• 30ppm/℃ gain drift/temperature

• 0.3mV input offset voltage

• 100kHz bandwidth

• 0.004% nonlinearity

• Small, automatic insertion standard 8-pin DIP package

• Worldwide safety standards:

-UL1577 (3750VRMS/1min.)

-CSA

-IEC/EN/DINEN60747-5-5

• Meets AEC-Q100 test guide requirements

• Automotive grade operating temperature range: -40℃~125℃

• Advanced Sigma-Delta (Σ-Δ) A/D conversion technology

• Fully differential circuit topology

ACPL-782T Applications

• Automotive motor inverter current/voltage sensing

• Automotive AC/DC and DC/DC conversion current/

voltage sensing

• Automotive battery ECU

• Automotive motor phase current sensing

• Isolation interface for temperature sensing

• General purpose current sensing and monitoring

Keywords：ACPL-782T Reference address：Small isolation amplifier technology for automobiles based on ACPL-782T

Previous article：Simulation of RC circuit charging and discharging process and determination of time constant
Next article：The circuit principle of high input resistance broadband buffer amplifier composed of push-pull circuit

Popular Resources
Popular amplifiers