Domestic synchronous sampling 24 bit analog-to-digital converter replaces ADS1278 for high-precision power measurement of new energy inverters

The power measurement of new energy inverters is an important part of power generation efficiency evaluation, grid connected power quality monitoring, and fault warning. In order to meet the requirements of high-precision power measurement of new energy inverters for multi-channel synchronization and wide dynamic range signal acquisition, this article mainly introduces the application of synchronous sampling 24 bit analog-to-digital converter GX1278 in high-precision power measurement of new energy inverters. GX1278 can PIN TO PIN replace ADS1278, which is an ideal replacement solution.

The power fluctuation range of new energy inverters is large, and power calculation depends on the phase synchronization of voltage and current. GX1278 supports 8-channel and 24 bit high precision, which can achieve accurate acquisition of the full power range of the inverter. GX1278 supports a data sampling rate of up to 144kSPS, which enables extremely fine quantization of input analog signals, effectively improving measurement accuracy and system resolution.

GX1278 offers four mode options: High Speed (HS) mode, which has the fastest speed and can achieve 144kSps with a 37MHz clock, and a -3dB bandwidth of 70kHz; High precision (HR) mode, with the highest accuracy, SNR up to 111.7dB, THD up to -122.9dB, and power consumption of only 20.8mW/channel; Low power (LP) mode, with the same output rate as HR mode but almost halved power consumption; Low speed (LS) mode, suitable for low-speed acquisition, with power consumption as low as 2.7mW/channel. And the chip is directly controlled by PIN pins, without the need to compile registers, making it convenient for customers to use.

The GX1278 uses a high-order multi bit Delta sigma modulator to shape the in band noise and filter it out through an on-chip digital extraction filter, resulting in very low in band noise power. There are two types of on-chip digital filters to choose from: a high bandwidth FIR filter with an effective bandwidth of 90.6% of the Nyquist bandwidth and an in band ripple of less than ± 0.005dB; and a low latency SINC filter that can generate stable data output within 6 cycles and has better noise performance. Its characteristics are as follows:

8-channel synchronous sampling, data rate up to 144kSps

High bandwidth FIR filters and low latency SINC filters are optional

Low power consumption: HS mode: 34.0mW/channel;

HR mode: 20.8mW/channel;

LP mode: 10.9mW/channel;

LS mode: 2.7mW/channel;

Rail to rail input common mode level

Common mode rejection ratio: 116dB

Analog power supply 5V; digital power supply 1.8V

IO power supply: 1.8V~3.3V

SPI or frame synchronization interface, supporting daisy chain mode

ESD level: HBM ± 2kV, CDM ± 2kV; Latch up ± 600mA

• Operating temperature range: -40 ° C to+85 ° C