HCPL-7800-000E

The HCPL-7800-000E is a high-precision isolation amplifier from Broadcom designed specifically for motor drive current sensing and other applications requiring accurate current measurement in the presence of high common-mode voltages. The device amplifies the small differential voltage developed across a shunt resistor while providing 3750 Vrms galvanic isolation between the high-voltage side and the low-voltage measurement side. With ±0.05% gain accuracy and 0.3 mV maximum input offset, it delivers measurement precision comparable to costly closed-loop Hall effect sensors but at a fraction of the cost. The sigma-delta modulation and digital isolation technique ensure excellent noise immunity and long-term stability.

The HCPL-7800-000E uses a sigma-delta analog-to-digital converter on the input side to digitize the differential voltage from the shunt resistor. The digitized signal is transmitted across an optical isolation barrier to the output side, where a DAC reconstructs the analog signal and an output amplifier drives the final voltage output. This approach provides excellent isolation, linearity, and noise immunity. The input amplifier has high common-mode rejection (95 dB at DC) to reject the large common-mode voltages present in motor drive applications. The gain is laser-trimmed to ±0.05% accuracy at the factory. The 100 kHz bandwidth captures the harmonic content of motor currents for accurate field-oriented control (FOC) algorithms.

• Three-phase motor drive current feedback for FOC
• Solar inverter MPPT current measurement
• UPS inverter output current monitoring
• EV/HEV battery current sensing
• Welding equipment current regulation