The ACPL-7970 is an isolated sigma-delta modulator designed for voltage sensing in high-voltage applications. It converts an analog input signal into a high-speed single-bit data stream using sigma-delta modulation technology and provides galvanic isolation using optical coupling. This allows accurate measurement of voltages in noisy environments, particularly in motor drives and power inverters.

Applications:

• Voltage sensing in motor drives
• Voltage sensing in power inverters
• Isolated data acquisition
• Current sensing applications (with external shunt resistor)
• Renewable energy systems (solar, wind)

Features:

• Isolated sigma-delta modulator
• 16-bit resolution (typical)
• High common-mode transient immunity (CMTI)
• Over-sampling architecture
• Galvanic isolation barrier
• Compact SO-16 package
• RoHS compliant

Benefits:

• Provides accurate voltage measurements in high-voltage environments
• Eliminates ground loops and noise
• Simplifies system design with integrated isolation
• Enables safe and reliable operation
• Reduces component count and board space
• Improved system performance due to high resolution and CMTI

Additional Details:

The ACPL-7970 modulates the input voltage into a single-bit data stream that is transmitted across an isolation barrier. The receiving end uses a digital filter (typically a sinc3 filter) to reconstruct the original analog signal. The high CMTI ensures that the data stream is not corrupted by transient voltages. The isolation barrier provides a high degree of electrical isolation between the input and output circuits, protecting sensitive downstream components from high voltages. The ACPL-7970 is available in a compact SO-16 package for easy board mounting. It offers excellent linearity and stability over temperature.

The device requires an external clock signal and an external digital filter for proper operation. The recommended clock frequency is typically in the MHz range. The output data stream is in a digital format that can be easily processed by a microcontroller or a digital signal processor (DSP). The isolated modulator enables precision voltage measurement, which is crucial for applications where safety and accurate control are essential.