New Industry Products

Current, Voltage, and Charge Monitor for High Voltage Battery Packs

December 19, 2019 by Paul Shepard

The LTC2949 from Analog Devices is a high precision current, voltage, temperature, charge and energy meter for electrical and hybrid vehicles and other isolated current sense applications. It infers charge and energy flowing in and out of the battery pack by monitoring simultaneously the voltage drop over up to two sense resistors and the battery pack voltage.

Low offset ΔΣ ADCs ensure accurate measurement of voltage and current with insignificant power loss. Continuous integration of current and power ensures lossless tracking of charge and energy delivered or received by the battery pack. It is expected to find use in a variety of applications including; electric and hybrid vehicles, isolated current sensing, backup battery systems, high-power portable equipment, and so on.

The built-in serial interface can be configured to support isolated isoSPI communication to the host or as SPI interface.

The LTC2949 features 12 internally buffered high impedance inputs (V1 to V12) for measuring voltages from external sensors or resistor dividers allowing to measure temperatures, HV-Link voltages, chassis isolation and supervise contactor states. LTC2949 has up to five programmable digital outputs which can be set to ground, supply or toggling at 400kHz.

Programmable threshold and tracking registers reduce digital traffic to the host.

Summary of specifications and features

  • Measures Battery Stack Voltage, Current and Power
  • Indicates Accumulated Battery Charge and Energy
  • 20-Bit Current Measurement with <1μV Offset
  • Built-In Isolated isoSPI™ or SPI Interface
  • LTC68xx/ADBMS68xx Compatible, Supports Synchronous Measurements with Cell Monitors
  • Up to 12 Buffered Voltage Measurement Inputs
  • Up to 5 GPOs, Configurable to Drive Ground, Supply or Toggling at 400kHz
  • High or Low Side Current Sense
  • 3% Current and Voltage Accuracy
  • 1% Energy and Charge Accuracy
  • True Average ADCs
  • I2C EEPROM Interface to Store Board Calibration Factors
  • Threshold Registers for all Measured Quantities
  • Engineered for ISO26262 Compliant Systems
  • Open Wire Detection on Input Pins
  • Available in 48-Lead LQFP Package
  • AEC-Q100 Qualified for Automotive Applications