Application of an 8-Channel Simultaneous Sampling ADC (CM2248) in Power Systems

01 Introduction

The CM2248 is a 16-bit, 8-channel simultaneous sampling ADC launched by Simu Microelectronics. Each channel integrates analog input clamp protection, a second-order anti-aliasing filter, a track-and-hold amplifier, a 16-bit SAR ADC, and a flexible on-chip digital filter.

The CM2248 operates from a single 5 V supply while supporting true bipolar input signals of ±10 V or ±5 V. All channels can sample and output data at a throughput rate of 200 kSPS. The analog input impedance of each channel is 1 MΩ, and the input clamp protection circuitry can withstand overvoltage up to ±16.5 V. The device is pin-compatible with ADI’s AD7606 and TI’s ADS8588.

Appearance of the structure

Pin configuration

Architecture Diagram

Typical Connection Diagram

02 Features

(1)Bipolar analog input ranges: ±10 V, ±5 V

(2)5 V analog supply, VDRIVE: 2.3 V to 5 V

(3)8 simultaneous sampling input channels

(4)LQFP64 10 × 10 package

(5 )Fully integrated data acquisition solution

--Analog input clamp protection

--Input buffer with 1 MΩ analog input impedance

--Second-order anti-aliasing analog filter

--On-chip precision reference and buffer

--16-bit, 200 kSPS ADC (all channels)

--Oversampling capability via digital filtering

(6)Flexible parallel/serial interfaces

--SPI/QSPI/MICROWIRE/DSP compatible

(7)Performance

--Analog input ESD up to 8 kV

--92 dB SNR, –105 dB THD

--±1 LSB INL, ±0.8 LSB DNL

--Low power consumption: 150 mW in operating mode, 30 mW in standby mode

03 Solution Overview

A power system consists of two main components: the primary system (high voltage, including generators, power networks, and loads) and the secondary system (low voltage, ensuring the safe, reliable, and economic operation of the primary system through its information systems and control mechanisms). To reduce the total installed capacity and improve the reliability and economy of power supply, the interconnection of power systems has become a major trend. However, this also makes the grid more vulnerable, with localized faults potentially threatening the entire power system. Consequently, power monitoring systems have become an essential part of ensuring the reliable operation of the grid. The CM2248 is mainly used in two key areas of power systems:

Power Monitoring System

Power monitoring systems can continuously monitor the operational status of the power system while recording data and events occurring in the system. Key parameters monitored include:

1. Voltage: Instantaneous voltage, voltage phasors (RMS value and phase), fundamental voltage phasors, harmonic voltage phasors, etc.

2. Current: Instantaneous current, current phasors, fundamental and harmonic phasors

3. Frequency

4. Power: Active power, reactive power, apparent power

5. Energy: Active energy and reactive energy

6. Operational status of various components

The CM2248 is an 8-channel simultaneous sampling analog front end, making it easy to measure real-time voltage, current, and phase differences. This enables easy calculation of power factor, apparent power, energy, and more. Additionally, its high ESD protection and rigorous production testing make it highly suitable for power system applications.

New Energy Grid Integration (Wind, Solar, etc.)

For reliable grid operation, there are strict requirements for integrating renewable energy sources such as wind and solar power. This includes meeting frequency, power factor, and other criteria. The integration of renewable energy requires DC-AC inversion, and voltage/current monitoring for the inverter also demands a high-precision simultaneous sampling system to meet grid connection requirements. The CM2248 is well-suited to meet these demands.

04 Product Advantages

In summary, the CM2248 offers high integration, a high SNR of 92 dB, and excellent distortion performance with –105 dB THD, making it highly suitable for high-precision signal feedback acquisition in various ATE applications. In terms of performance, the CM2248 directly competes with ADI’s AD7606 and TI’s ADS8588.