STMicroelectronics L99BM2C Multicell Battery Monitoring/Balancing IC
STMicroelectronics L99BM2C Multicell Battery Monitoring and Balancing IC is a current, voltage, charge, and isolation monitor for HV battery packs. It is part of the L99BM2 chipset for battery management systems and can be inserted as an addressable element of the same isolated daisy chain (VIF).
The L99BM2C is a highly integrated pack monitor. It monitors instantaneous pack current via an external shunt resistor and provides current measurements synchronized with the battery cells' voltages when used with the L99BM218 cell-monitoring chip. Current is also integrated over time to accumulate pack charge information.
L99BM2C also monitors the pack current to detect overcurrent and short-circuit events. The current measurement function and short-circuit detection are fully redundant and embed safety checks. The IC also features 10 gate pre-drivers for driving external FETs and optocouplers. These devices can be used in conjunction with 11 analog inputs to perform fully differential voltage measurements and monitor several key voltages in the HV system.
The voltage ADC supports both absolute and ratiometric measurements, providing maximum flexibility and accuracy for temperature measurement via external NTCs. L99BM2C integrates 5V and 3.3V LDOs available for biasing external sensors and supplying companion chips such as ST automotive EEPROMs. An SPI Master and an I2C Master enable interfacing with external sensors and EEPROMs.
The STMicroelectronics L99BM2C has been designed to enable easy and reliable interaction with the L99BM2P companion pyro-switch driver. The chipset has been designed to achieve ultra-fast detection and reaction to short-circuit failures.
Features
- -40°C to +125°C operating temperature range
- HBM ESD classification level 2
- CDM ESD classification level C4B
- Two independent current sense ADCs
- 18-bit resolution
- Input range = ±100mV
- Integrated programmable digital filtering with a cut-off frequency from 3.5kHz to 5Hz for instantaneous current measurement
- Fully redundant architecture with cross-check on every current sample
- Integrated Coulomb counter
- Fully redundant short circuit detector with programmable threshold and ultra-fast reaction time
- Two programmable (level/PWM encoded) FAULT outputs
- 10 gate pre-drivers are also compatible with optocouplers
- 11 fully differential analog inputs
- Seven configurable GPIO
- SPI and I2C Controller peripherals to interface up to two external EEPROMs, L99BM2P pyro driver, and sensors
- SPI Target for direct MCU interface
- 3.3V (VTREF) and 5V (V5V) LDOs for external sensors supply and biasing
- Embedded NVM for configuration parameters storage and runtime configuration integrity check
- Ultra-fast vertical interface peripheral for isolated communication
- Compatible with 18S L99BM218 cell monitoring chip with a max desynchronization time of 7µs at a system level
Applications
- Energy storage systems
- UPS
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