SLYY222 November   2023 ADC12DJ5200RF , ADS127L11 , REF35 , REF70 , TPS62912 , TPS62913 , TPS7A20 , TPS7A94 , TPSM82912 , TPSM82913

 

  1.   1
  2.   Overview
  3.   At a glance
  4.   Noise and ADCs
  5.   Defining noise and precision in a power architecture
  6.   Innovations in low-noise and low-power voltage references
  7.   Innovations in ultra-low-noise voltage references
  8.   Improving noise and thermal performance with simplified power architectures
  9.   High-current low noise with LDO supply rails
  10.   Innovations in precision battery monitoring
  11.   Conclusion
  12.   Additional resources

Innovations in precision battery monitoring

The BQ79718-Q1 battery monitor for electric vehicles has an accuracy of 1 mV for measuring cell voltages. This higher accuracy and precision enable automotive original equipment manufacturers to deliver extended ranges without increasing the cost or capacity of the EV battery pack. As expected, many system and environmental factors contribute to inaccuracies in voltage measurements, including drift with temperature and lifetime, supply noise, and die stress induced from board flex.

TI has incorporated several technologies on a single die to reduce environmental effects and achieve higher-accuracy voltage measurements. For example:

  • A buried Zener diode keeps the buried junction well below the surface and less susceptible to hot carriers. This diode enables a very stable voltage reference over an integrated circuit’s (IC) temperature and lifetime.
  • When soldering a battery monitor to a PCB, the flex of the PCB causes the die to bend very slightly, causing inaccuracies in voltage measurements. An integrated strain gauge measures this bend and corrects the voltage measurement.
  • Integrated cell balancing field-effect transistors and power supplies cause the die to heat up, which results in voltage-measurement errors caused by temperature deviations. The BQ79718-Q1 integrates temperature sensors so that the device can calibrate voltage measurements across temperature, ensuring the best accuracy.

Application-specific ICs such as the BQ79718 and BQ79731-Q1 can help solve system-level issues in a single chip, enabling system designers to achieve the best performance without sacrificing time to market.