12-Channel High-Voltage Data Acquisition System

Description

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The MAX17823B is a data acquisition system for the management of high-voltage battery modules. The system features 12-bit SAR ADC that can measure 12 cell voltages and two temperatures in 161μs. There are 12 internal switches for cell balancing and extensive built-in diagnostics. Up to 32 devices can be daisy-chained together to manage 384 cells and monitor 64 temperatures.

Cell voltages (0 to 5V) are measured differentially over a 65V common-mode range. Cell measurements have a typical accuracy of 2mV (3.6V cell, +25°C). If oversampling is enabled, up to 128 measurements per channel can be averaged internally with 14-bit resolution. The system can shut itself down in the event of a thermal overload by measuring its own die temperature.

The system uses Maxim’s battery-management UART protocol for robust communications and when used in conjunction with the MAX17880 12-channel battery monitor, they are ideal for automotive battery-management systems that require a high safety integrity level.

Key Features

• AEC-Q100 Grade 2 Temperature Range
  • -40°C to +105°C
• Operating Voltage from 9V to 65V
• Ultra-Low-Power Operation
  • Standby Mode: 2mA
  • Shutdown Mode: 2μA
• 12 Cell-Voltage-Measurement Channels
  • 2mV Accuracy (3.6V, +25° C)
  • 5mV Accuracy (0°C to +45°C)
  • 10mV Accuracy (-40°C to +105°C)
• 12 Cell-Balancing Switches
  • Up to 150mA per Switch
  • Emergency-Discharge Mode
• Two Temperature-Measurement Channels
• Die Temperature Measurement
• Automatic Thermal Protection
• 29 Voltage Threshold Alerts
  • 12 Over-Voltage Faults
  • 12 Under-Voltage Faults
  • Two Over-Temperature Faults
  • Two Under-Temperature Faults
  • One Cell Mismatch Alert (highest cell versus lowest cell)
• Four GPIOs
• Built-in Diagnostics to Support ASIL D and FMEA Requirements
• Battery-Management UART Protocol
  • Daisy-Chain Up to 32 Devices
  • Communication Port Isolation
  • Up to 2Mbps Baud Rate (Autodetect)
  • 1.5µs Propagation Delay per Device
  • Packet-Error Checking (PEC)
• Factory-Trimmed Oscillators
  • No External Crystals Required
• 10mm x 10mm Package (64-Pin LQFP)

Applications/Uses

• Battery Packs
• Battery Systems
• Electric Bikes
• Electric Vehicles and Hybrid Vehicle (HEV)
• High-Power Battery Backup Systems
• High-Voltage, Multi-Cell Series-Stacked-
• Power Tools
• SuperCap Backup Systems