SHUNT-BASED DC CURRENT SENSING WITH INTEGRATED SAFETY
Melexis launches the new MLX91231, increasing its automotive current sensor range by adding a shunt-based sensing solution. Meeting functional safety requirements, this IVT (current, voltage, and temperature) device combines high accuracy with the intelligence and flexibility of a digital microcontroller unit (MCU). The MLX91231 is tailored for DCDC converters, battery terminal sensors, low and high-voltage power distribution, and disconnection devices. The MLX91231 is a shunt interface for DC current sensing. It integrates IVT measurement capability (current, voltage and temperature), embeds a microcontroller and supports safety applications.
HALL-BASED DC CURRENT SENSING WITH UNPRECEDENTED ACCURACY
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 MLX91230 is removing an important part of the burden from the integrator in developing all the safety mechanisms. Boosting accuracy of Hall-effect DC current sensing, the MLX91230 comes with 0.5% accuracy over temperature (-40°C to 125°C) for a 1% lifetime drift all-in. The MCU enables automatic gain control to cover higher dynamic ranges, and the on-board flash memory supports custom software and extensive compensation of system imperfections. Supplied with a regulated 5V or directly connected to the 12V battery, the MLX91230 in SOIC8 outputs measurements and diagnostics either on LIN bus or via UART.
Features and Benefits
IVT battery measurements:
- Shunt based current sensor-Internal (PTAT) temperature sensor
- Voltage measurement
▪ Internal dividers for 12V or 24V/48V batteries
▪ External divider required for HV batteries
- Internal (PTAT) temperature sensor16-bit MCU with 32 KB Flash, 128 B Flash CS, 20 KB ROM, 2 KB RAM and 512 B EEPROM Memory
LIN/UART communication interfaces
- LIN Physical Layer compliant to ISO17987-4 and SAE J2602
- UART as CAN MCU bridge
- Wake-up on LIN and UART or on internal timerOvercurrent detection functionality (<500μs)
Magnetic range of 512mT
Possible Automatic Gain Control (AGC) forhigher dynamic range
Low level SW libraries provided by Melexis
User programmable transfer characteristic
Supply voltage: 4.5 to 18V (12V battery supply capability)
Low current consumption (<21mA), programmable duty cycled sleep mode (RAM content maintained at <100μA)
Ambient temperature from -40°C to 125°C
ASIL compliant SEooC (Safety Element out of Context) according to ISO26262
AEC-Q100 Grade 1 automotive qualified
RoHS compliant package SOIC8 (DC)
Application Examples
- Battery Terminal Sensor 12V/24V
- Battery Management System 48V/HV
- Enabling Battery State of Charge (SoC), State of Health (SoH) and State of Function (SoF)
- Smart Battery Disconnect Unit, Junction Box or Power Relay Assembly
- Smart Pyrofuses
- Smart HV relays or contactors
- HV DC FastCharge current sensing
- Zone controller
2-wheelers
The current focus on electric vehicules is boosting the whole e-mobility industry. It is especially beneficial for the 2 and 3 wheelers which also require to solve similar constraints: from battery management (sufficient power, longevity and safety) to drive train efficiency and personalization.
E-bike
Combining exercise and mobility was never so easy thanks to E-bikes. Because they support you while moving, they are an attractive option. Modern technology optimizes the pedal assist by the electrical engine while minimizing the battery usage. Thanks to Melexis ICs you control the calories and the battery energy you burn.
E-forklift
Industrial e-vehicles only function well if a number of sensors keep an eye on battery management, actuator positions and people safety around the vehicle. Melexis has been very industrious designing the right ICs for this market.
Main DCDC
The DC/DC converter produces low voltage DC electricity (e.g. 12 V, 14 V, 24 V) from the high voltage battery (e.g. 48 V up to 800 V) to supply the boardnet and charge the low voltage battery.
