INTEGRATED SAFETY
SMART IVT BATTERY SENSOR
The MLX91231 is a smart Shunt-based current sensor and is part of Melexis Gen 3 portfolio. With a measurement of three physical quantities (current, voltage and temperature) and a dedicated 32 KB Flash memory on a single IC, this ASIL compliant product is ideal for safety applications. With its diagnostics the MLX91231 is removing an important part of the burden from the integrator in developing all the safety mechanisms. That includes an on-chip overcurrent detection.
The MLX91231 comes with ±0.25% accuracy over temperature (-40° to 125°C) and over lifetime all-in. It is boosting the accuracy of Shunt DC current sensing. The integrated MCU enables automatic gain control to cover higher dynamic ranges. The on-board flash memory supports custom software deployment and extensive compensation of system imperfections. Supplied with a regulated 5V or directly connected to the 12V battery, the MLX91231 outputs measurements and diagnostics either on a LIN bus or via UART.
Application examples:
Battery Terminal Sensor 12V/24V
Smart Battery Disconnect Unit, Junction Box or Power Relay Assembly
HV DC FastCharge current sensing
Battery Management System 48V/HV
Smart Pyrofuses
Zone controller
Enabling Battery State of Charge (SoC), State of Health (SoH) and State of Function (SoF)
Smart HV relays or contactors
Power distribution unit
Key features of the MLX91231:
▪ IVT battery measurements:
- Shunt based current sensor
- Internal (PTAT) temperature sensor
- Voltage measurement
▪ Internal dividers for 12V or 24V/48V battery
▪ External divider required for high voltage batteries
▪ Possible Automatic Gain Control (AGC) for higher dynamic range
▪ User programmable transfer characteristic
▪ 16-bit MCU Memories:
- 32 KB Flash
- 128 B Flash Configuration Sector
- 20 KB ROM
- 2 KB RAM
- 512 B EEPROM
▪ Ambient temperature from -40°C to 125°C
▪ ISO 26262 ASIL compliant SEooC (Safety Element out of Context)
▪ LIN/UART communication
- LIN Physical Layer compliant to ISO17987-4 and SAE J2602
- UART as CAN MCU bridge
- Wake-up on LIN and UART or on internal timer
▪ Supply voltage: 4.5 to 18V (12V battery supply capability)
▪ Low level SW libraries provided by Melexis
▪ AEC-Q100 Grade 1 automotive qualified
▪ Overcurrent detection functionality (<500μs)
▪ Low current consumption (<21mA), programmable duty cycled sleep mode (RAM content maintained at <100µA)
▪ Magnetic range from -100mV to 256mV
▪ RoHS compliant package SOIC8 (DC)
Development kit for the smart MLX91231
The DVK91231 provides a mother board and a sensor board to enable comprehensive performance evaluation of the MLX91231’s capabilities. Note that a Melexis Universal Master MUM (not included) is also required.
The DVK91231 includes:
- Mother board: junction between the MUM Programmer (not included in the DVK) and the sensor board
- Sensor board: ready to use with a MLX91231 already soldered
- Connectors: between mother board and MUM programmer, between mother board and sensor board
- Shunt bar
- Spare MLX91231 ICs (x2)
The DVK91231 does not include:
- Melexis Universal Master (MUM): programmer tool and LIN master