Replacing the AD7656, the GX7656 ADC Is Applied to Online Power Grid Monitoring

The online monitoring system for power equipment consists of an online temperature monitoring device, an online arrester insulation monitoring device, and an online circuit breaker monitoring device. The system covers the monitoring of insulation state parameters of major electrical equipment in substations, with multiple monitoring parameters and complete functions.

In the monitoring system, a high-precision ADC module converts continuous time-domain analog signals into digital signals, and the main control unit analyzes and calculates the sampled data to achieve real-time assessment of power grid operating status, fault location, and online evaluation of power quality. Multi-channel synchronous sampling can complete the synchronous acquisition of three-phase voltage and three-phase current of the power grid in one go, avoiding the phase deviation problem of time-division sampling. This solution can use the GX7656.

The GX7656 is specially designed for multi-channel high-precision acquisition scenarios and meets the sampling requirements of multi-phase voltage and current. The chip has low input noise, and the conversion rate of each channel is as high as 250 kSPS, enabling precise acquisition of small-amplitude voltage and current variations and high-order harmonic signals in the power grid. It supports parallel mode or serial mode, configured through different connection modes of hardware pins. This function creates multiple connection conditions for interfacing the device with a microprocessor or DSP.

GX7656 performance advantages:

Supports Pin-To-Pin in-place replacement of the AD7656

Product dimensions, pins, functions, and timing are compatible with the reference product; single 5 V power supply, compatible with ±15 V power supply pins, facilitating application

Higher signal-to-noise ratio and higher linearity

Lower bipolar zero-level error and lower positive/negative full-scale error

Higher channel isolation

ENOB: 14.5 Bit (typical value)

SNR: 89.5 dB (typical value)

SNDR: 89 dB (typical value)

SFDR: -103 dB (typical value)

THD: -100 dB (typical value)

INL: ±1 LSB (typical value)

DNL: ±0.5 LSB (typical value)

Operating power consumption: 110 mW (internal reference)

Operating temperature: -55°C to +125°C

Uses a 64-pin QFP package, available in both ceramic package and plastic package forms